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| author |   Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-27 06:32:31 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-28 20:08:19 -0300 |
| commit | 43f71d93a0cb342f0c918fba3f6abb7661e40ad2 (patch) | |
| tree | a1dc7288bc480e7027ca1827ca4876472fa12e40 /Documentation/DocBook/media/v4l/compat.xml | |
| parent | Merge tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media (diff) | |
| download | linux-dev-43f71d93a0cb342f0c918fba3f6abb7661e40ad2.tar.xz linux-dev-43f71d93a0cb342f0c918fba3f6abb7661e40ad2.zip | |
doc-rst: Remove the media docbook
Now that all media documentation was converted to Sphinx, we
should get rid of the old DocBook one, as we don't want people
to submit patches against the old stuff.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l/compat.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/compat.xml | 2723 |
1 files changed, 0 insertions, 2723 deletions
diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml deleted file mode 100644 index 82fa328abd58..000000000000 --- a/Documentation/DocBook/media/v4l/compat.xml +++ /dev/null @@ -1,2723 +0,0 @@ - <title>Changes</title> - - <para>The following chapters document the evolution of the V4L2 API, -errata or extensions. They are also intended to help application and -driver writers to port or update their code.</para> - - <section id="diff-v4l"> - <title>Differences between V4L and V4L2</title> - - <para>The Video For Linux API was first introduced in Linux 2.1 to -unify and replace various TV and radio device related interfaces, -developed independently by driver writers in prior years. Starting -with Linux 2.5 the much improved V4L2 API replaces the V4L API. -The support for the old V4L calls were removed from Kernel, but the -library <xref linkend="libv4l" /> supports the conversion of a V4L -API system call into a V4L2 one.</para> - - <section> - <title>Opening and Closing Devices</title> - - <para>For compatibility reasons the character device file names -recommended for V4L2 video capture, overlay, radio and raw -vbi capture devices did not change from those used by V4L. They are -listed in <xref linkend="devices" /> and below in <xref - linkend="v4l-dev" />.</para> - - <para>The teletext devices (minor range 192-223) have been removed in -V4L2 and no longer exist. There is no hardware available anymore for handling -pure teletext. Instead raw or sliced VBI is used.</para> - - <para>The V4L <filename>videodev</filename> module automatically -assigns minor numbers to drivers in load order, depending on the -registered device type. We recommend that V4L2 drivers by default -register devices with the same numbers, but the system administrator -can assign arbitrary minor numbers using driver module options. The -major device number remains 81.</para> - - <table id="v4l-dev"> - <title>V4L Device Types, Names and Numbers</title> - <tgroup cols="3"> - <thead> - <row> - <entry>Device Type</entry> - <entry>File Name</entry> - <entry>Minor Numbers</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry>Video capture and overlay</entry> - <entry><para><filename>/dev/video</filename> and -<filename>/dev/bttv0</filename><footnote> <para>According to -Documentation/devices.txt these should be symbolic links to -<filename>/dev/video0</filename>. Note the original bttv interface is -not compatible with V4L or V4L2.</para> </footnote>, -<filename>/dev/video0</filename> to -<filename>/dev/video63</filename></para></entry> - <entry>0-63</entry> - </row> - <row> - <entry>Radio receiver</entry> - <entry><para><filename>/dev/radio</filename><footnote> - <para>According to -<filename>Documentation/devices.txt</filename> a symbolic link to -<filename>/dev/radio0</filename>.</para> - </footnote>, <filename>/dev/radio0</filename> to -<filename>/dev/radio63</filename></para></entry> - <entry>64-127</entry> - </row> - <row> - <entry>Raw VBI capture</entry> - <entry><para><filename>/dev/vbi</filename>, -<filename>/dev/vbi0</filename> to -<filename>/dev/vbi31</filename></para></entry> - <entry>224-255</entry> - </row> - </tbody> - </tgroup> - </table> - - <para>V4L prohibits (or used to prohibit) multiple opens of a -device file. V4L2 drivers <emphasis>may</emphasis> support multiple -opens, see <xref linkend="open" /> for details and consequences.</para> - - <para>V4L drivers respond to V4L2 ioctls with an &EINVAL;.</para> - </section> - - <section> - <title>Querying Capabilities</title> - - <para>The V4L <constant>VIDIOCGCAP</constant> ioctl is -equivalent to V4L2's &VIDIOC-QUERYCAP;.</para> - - <para>The <structfield>name</structfield> field in struct -<structname>video_capability</structname> became -<structfield>card</structfield> in &v4l2-capability;, -<structfield>type</structfield> was replaced by -<structfield>capabilities</structfield>. Note V4L2 does not -distinguish between device types like this, better think of basic -video input, video output and radio devices supporting a set of -related functions like video capturing, video overlay and VBI -capturing. See <xref linkend="open" /> for an -introduction.<informaltable> - <tgroup cols="3"> - <thead> - <row> - <entry>struct -<structname>video_capability</structname> -<structfield>type</structfield></entry> - <entry>&v4l2-capability; -<structfield>capabilities</structfield> flags</entry> - <entry>Purpose</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry><constant>VID_TYPE_CAPTURE</constant></entry> - <entry><constant>V4L2_CAP_VIDEO_CAPTURE</constant></entry> - <entry>The <link linkend="capture">video -capture</link> interface is supported.</entry> - </row> - <row> - <entry><constant>VID_TYPE_TUNER</constant></entry> - <entry><constant>V4L2_CAP_TUNER</constant></entry> - <entry>The device has a <link linkend="tuner">tuner or -modulator</link>.</entry> - </row> - <row> - <entry><constant>VID_TYPE_TELETEXT</constant></entry> - <entry><constant>V4L2_CAP_VBI_CAPTURE</constant></entry> - <entry>The <link linkend="raw-vbi">raw VBI -capture</link> interface is supported.</entry> - </row> - <row> - <entry><constant>VID_TYPE_OVERLAY</constant></entry> - <entry><constant>V4L2_CAP_VIDEO_OVERLAY</constant></entry> - <entry>The <link linkend="overlay">video -overlay</link> interface is supported.</entry> - </row> - <row> - <entry><constant>VID_TYPE_CHROMAKEY</constant></entry> - <entry><constant>V4L2_FBUF_CAP_CHROMAKEY</constant> in -field <structfield>capability</structfield> of -&v4l2-framebuffer;</entry> - <entry>Whether chromakey overlay is supported. For -more information on overlay see -<xref linkend="overlay" />.</entry> - </row> - <row> - <entry><constant>VID_TYPE_CLIPPING</constant></entry> - <entry><constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant> -and <constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant> in field -<structfield>capability</structfield> of &v4l2-framebuffer;</entry> - <entry>Whether clipping the overlaid image is -supported, see <xref linkend="overlay" />.</entry> - </row> - <row> - <entry><constant>VID_TYPE_FRAMERAM</constant></entry> - <entry><constant>V4L2_FBUF_CAP_EXTERNOVERLAY</constant> -<emphasis>not set</emphasis> in field -<structfield>capability</structfield> of &v4l2-framebuffer;</entry> - <entry>Whether overlay overwrites frame buffer memory, -see <xref linkend="overlay" />.</entry> - </row> - <row> - <entry><constant>VID_TYPE_SCALES</constant></entry> - <entry><constant>-</constant></entry> - <entry>This flag indicates if the hardware can scale -images. The V4L2 API implies the scale factor by setting the cropping -dimensions and image size with the &VIDIOC-S-CROP; and &VIDIOC-S-FMT; -ioctl, respectively. The driver returns the closest sizes possible. -For more information on cropping and scaling see <xref - linkend="crop" />.</entry> - </row> - <row> - <entry><constant>VID_TYPE_MONOCHROME</constant></entry> - <entry><constant>-</constant></entry> - <entry>Applications can enumerate the supported image -formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device -supports grey scale capturing only. For more information on image -formats see <xref linkend="pixfmt" />.</entry> - </row> - <row> - <entry><constant>VID_TYPE_SUBCAPTURE</constant></entry> - <entry><constant>-</constant></entry> - <entry>Applications can call the &VIDIOC-G-CROP; ioctl -to determine if the device supports capturing a subsection of the full -picture ("cropping" in V4L2). If not, the ioctl returns the &EINVAL;. -For more information on cropping and scaling see <xref - linkend="crop" />.</entry> - </row> - <row> - <entry><constant>VID_TYPE_MPEG_DECODER</constant></entry> - <entry><constant>-</constant></entry> - <entry>Applications can enumerate the supported image -formats with the &VIDIOC-ENUM-FMT; ioctl to determine if the device -supports MPEG streams.</entry> - </row> - <row> - <entry><constant>VID_TYPE_MPEG_ENCODER</constant></entry> - <entry><constant>-</constant></entry> - <entry>See above.</entry> - </row> - <row> - <entry><constant>VID_TYPE_MJPEG_DECODER</constant></entry> - <entry><constant>-</constant></entry> - <entry>See above.</entry> - </row> - <row> - <entry><constant>VID_TYPE_MJPEG_ENCODER</constant></entry> - <entry><constant>-</constant></entry> - <entry>See above.</entry> - </row> - </tbody> - </tgroup> - </informaltable></para> - - <para>The <structfield>audios</structfield> field was replaced -by <structfield>capabilities</structfield> flag -<constant>V4L2_CAP_AUDIO</constant>, indicating -<emphasis>if</emphasis> the device has any audio inputs or outputs. To -determine their number applications can enumerate audio inputs with -the &VIDIOC-G-AUDIO; ioctl. The audio ioctls are described in <xref - linkend="audio" />.</para> - - <para>The <structfield>maxwidth</structfield>, -<structfield>maxheight</structfield>, -<structfield>minwidth</structfield> and -<structfield>minheight</structfield> fields were removed. Calling the -&VIDIOC-S-FMT; or &VIDIOC-TRY-FMT; ioctl with the desired dimensions -returns the closest size possible, taking into account the current -video standard, cropping and scaling limitations.</para> - </section> - - <section> - <title>Video Sources</title> - - <para>V4L provides the <constant>VIDIOCGCHAN</constant> and -<constant>VIDIOCSCHAN</constant> ioctl using struct -<structname>video_channel</structname> to enumerate -the video inputs of a V4L device. The equivalent V4L2 ioctls -are &VIDIOC-ENUMINPUT;, &VIDIOC-G-INPUT; and &VIDIOC-S-INPUT; -using &v4l2-input; as discussed in <xref linkend="video" />.</para> - - <para>The <structfield>channel</structfield> field counting -inputs was renamed to <structfield>index</structfield>, the video -input types were renamed as follows: <informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>struct <structname>video_channel</structname> -<structfield>type</structfield></entry> - <entry>&v4l2-input; -<structfield>type</structfield></entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry><constant>VIDEO_TYPE_TV</constant></entry> - <entry><constant>V4L2_INPUT_TYPE_TUNER</constant></entry> - </row> - <row> - <entry><constant>VIDEO_TYPE_CAMERA</constant></entry> - <entry><constant>V4L2_INPUT_TYPE_CAMERA</constant></entry> - </row> - </tbody> - </tgroup> - </informaltable></para> - - <para>Unlike the <structfield>tuners</structfield> field -expressing the number of tuners of this input, V4L2 assumes each video -input is connected to at most one tuner. However a tuner can have more -than one input, &ie; RF connectors, and a device can have multiple -tuners. The index number of the tuner associated with the input, if -any, is stored in field <structfield>tuner</structfield> of -&v4l2-input;. Enumeration of tuners is discussed in <xref - linkend="tuner" />.</para> - - <para>The redundant <constant>VIDEO_VC_TUNER</constant> flag was -dropped. Video inputs associated with a tuner are of type -<constant>V4L2_INPUT_TYPE_TUNER</constant>. The -<constant>VIDEO_VC_AUDIO</constant> flag was replaced by the -<structfield>audioset</structfield> field. V4L2 considers devices with -up to 32 audio inputs. Each set bit in the -<structfield>audioset</structfield> field represents one audio input -this video input combines with. For information about audio inputs and -how to switch between them see <xref linkend="audio" />.</para> - - <para>The <structfield>norm</structfield> field describing the -supported video standards was replaced by -<structfield>std</structfield>. The V4L specification mentions a flag -<constant>VIDEO_VC_NORM</constant> indicating whether the standard can -be changed. This flag was a later addition together with the -<structfield>norm</structfield> field and has been removed in the -meantime. V4L2 has a similar, albeit more comprehensive approach -to video standards, see <xref linkend="standard" /> for more -information.</para> - </section> - - <section> - <title>Tuning</title> - - <para>The V4L <constant>VIDIOCGTUNER</constant> and -<constant>VIDIOCSTUNER</constant> ioctl and struct -<structname>video_tuner</structname> can be used to enumerate the -tuners of a V4L TV or radio device. The equivalent V4L2 ioctls are -&VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; using &v4l2-tuner;. Tuners are -covered in <xref linkend="tuner" />.</para> - - <para>The <structfield>tuner</structfield> field counting tuners -was renamed to <structfield>index</structfield>. The fields -<structfield>name</structfield>, <structfield>rangelow</structfield> -and <structfield>rangehigh</structfield> remained unchanged.</para> - - <para>The <constant>VIDEO_TUNER_PAL</constant>, -<constant>VIDEO_TUNER_NTSC</constant> and -<constant>VIDEO_TUNER_SECAM</constant> flags indicating the supported -video standards were dropped. This information is now contained in the -associated &v4l2-input;. No replacement exists for the -<constant>VIDEO_TUNER_NORM</constant> flag indicating whether the -video standard can be switched. The <structfield>mode</structfield> -field to select a different video standard was replaced by a whole new -set of ioctls and structures described in <xref linkend="standard" />. -Due to its ubiquity it should be mentioned the BTTV driver supports -several standards in addition to the regular -<constant>VIDEO_MODE_PAL</constant> (0), -<constant>VIDEO_MODE_NTSC</constant>, -<constant>VIDEO_MODE_SECAM</constant> and -<constant>VIDEO_MODE_AUTO</constant> (3). Namely N/PAL Argentina, -M/PAL, N/PAL, and NTSC Japan with numbers 3-6 (sic).</para> - - <para>The <constant>VIDEO_TUNER_STEREO_ON</constant> flag -indicating stereo reception became -<constant>V4L2_TUNER_SUB_STEREO</constant> in field -<structfield>rxsubchans</structfield>. This field also permits the -detection of monaural and bilingual audio, see the definition of -&v4l2-tuner; for details. Presently no replacement exists for the -<constant>VIDEO_TUNER_RDS_ON</constant> and -<constant>VIDEO_TUNER_MBS_ON</constant> flags.</para> - - <para> The <constant>VIDEO_TUNER_LOW</constant> flag was renamed -to <constant>V4L2_TUNER_CAP_LOW</constant> in the &v4l2-tuner; -<structfield>capability</structfield> field.</para> - - <para>The <constant>VIDIOCGFREQ</constant> and -<constant>VIDIOCSFREQ</constant> ioctl to change the tuner frequency -where renamed to &VIDIOC-G-FREQUENCY; and &VIDIOC-S-FREQUENCY;. They -take a pointer to a &v4l2-frequency; instead of an unsigned long -integer.</para> - </section> - - <section id="v4l-image-properties"> - <title>Image Properties</title> - - <para>V4L2 has no equivalent of the -<constant>VIDIOCGPICT</constant> and <constant>VIDIOCSPICT</constant> -ioctl and struct <structname>video_picture</structname>. The following -fields where replaced by V4L2 controls accessible with the -&VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls:<informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>struct <structname>video_picture</structname></entry> - <entry>V4L2 Control ID</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry><structfield>brightness</structfield></entry> - <entry><constant>V4L2_CID_BRIGHTNESS</constant></entry> - </row> - <row> - <entry><structfield>hue</structfield></entry> - <entry><constant>V4L2_CID_HUE</constant></entry> - </row> - <row> - <entry><structfield>colour</structfield></entry> - <entry><constant>V4L2_CID_SATURATION</constant></entry> - </row> - <row> - <entry><structfield>contrast</structfield></entry> - <entry><constant>V4L2_CID_CONTRAST</constant></entry> - </row> - <row> - <entry><structfield>whiteness</structfield></entry> - <entry><constant>V4L2_CID_WHITENESS</constant></entry> - </row> - </tbody> - </tgroup> - </informaltable></para> - - <para>The V4L picture controls are assumed to range from 0 to -65535 with no particular reset value. The V4L2 API permits arbitrary -limits and defaults which can be queried with the &VIDIOC-QUERYCTRL; -ioctl. For general information about controls see <xref -linkend="control" />.</para> - - <para>The <structfield>depth</structfield> (average number of -bits per pixel) of a video image is implied by the selected image -format. V4L2 does not explicitly provide such information assuming -applications recognizing the format are aware of the image depth and -others need not know. The <structfield>palette</structfield> field -moved into the &v4l2-pix-format;:<informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>struct <structname>video_picture</structname> -<structfield>palette</structfield></entry> - <entry>&v4l2-pix-format; -<structfield>pixfmt</structfield></entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry><constant>VIDEO_PALETTE_GREY</constant></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-GREY"><constant>V4L2_PIX_FMT_GREY</constant></link></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_HI240</constant></entry> - <entry><para><link -linkend="pixfmt-reserved"><constant>V4L2_PIX_FMT_HI240</constant></link><footnote> - <para>This is a custom format used by the BTTV -driver, not one of the V4L2 standard formats.</para> - </footnote></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_RGB565</constant></entry> - <entry><para><link -linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_RGB565</constant></link></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_RGB555</constant></entry> - <entry><para><link -linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_RGB555</constant></link></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_RGB24</constant></entry> - <entry><para><link -linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_BGR24</constant></link></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_RGB32</constant></entry> - <entry><para><link -linkend="pixfmt-rgb"><constant>V4L2_PIX_FMT_BGR32</constant></link><footnote> - <para>Presumably all V4L RGB formats are -little-endian, although some drivers might interpret them according to machine endianness. V4L2 defines little-endian, big-endian and red/blue -swapped variants. For details see <xref linkend="pixfmt-rgb" />.</para> - </footnote></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_YUV422</constant></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link></para></entry> - </row> - <row> - <entry><para><constant>VIDEO_PALETTE_YUYV</constant><footnote> - <para><constant>VIDEO_PALETTE_YUV422</constant> -and <constant>VIDEO_PALETTE_YUYV</constant> are the same formats. Some -V4L drivers respond to one, some to the other.</para> - </footnote></para></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-YUYV"><constant>V4L2_PIX_FMT_YUYV</constant></link></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_UYVY</constant></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-UYVY"><constant>V4L2_PIX_FMT_UYVY</constant></link></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_YUV420</constant></entry> - <entry>None</entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_YUV411</constant></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-Y41P"><constant>V4L2_PIX_FMT_Y41P</constant></link><footnote> - <para>Not to be confused with -<constant>V4L2_PIX_FMT_YUV411P</constant>, which is a planar -format.</para> </footnote></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_RAW</constant></entry> - <entry><para>None<footnote> <para>V4L explains this -as: "RAW capture (BT848)"</para> </footnote></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_YUV422P</constant></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-YUV422P"><constant>V4L2_PIX_FMT_YUV422P</constant></link></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_YUV411P</constant></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-YUV411P"><constant>V4L2_PIX_FMT_YUV411P</constant></link><footnote> - <para>Not to be confused with -<constant>V4L2_PIX_FMT_Y41P</constant>, which is a packed -format.</para> </footnote></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_YUV420P</constant></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-YVU420"><constant>V4L2_PIX_FMT_YVU420</constant></link></para></entry> - </row> - <row> - <entry><constant>VIDEO_PALETTE_YUV410P</constant></entry> - <entry><para><link -linkend="V4L2-PIX-FMT-YVU410"><constant>V4L2_PIX_FMT_YVU410</constant></link></para></entry> - </row> - </tbody> - </tgroup> - </informaltable></para> - - <para>V4L2 image formats are defined in <xref -linkend="pixfmt" />. The image format can be selected with the -&VIDIOC-S-FMT; ioctl.</para> - </section> - - <section> - <title>Audio</title> - - <para>The <constant>VIDIOCGAUDIO</constant> and -<constant>VIDIOCSAUDIO</constant> ioctl and struct -<structname>video_audio</structname> are used to enumerate the -audio inputs of a V4L device. The equivalent V4L2 ioctls are -&VIDIOC-G-AUDIO; and &VIDIOC-S-AUDIO; using &v4l2-audio; as -discussed in <xref linkend="audio" />.</para> - - <para>The <structfield>audio</structfield> "channel number" -field counting audio inputs was renamed to -<structfield>index</structfield>.</para> - - <para>On <constant>VIDIOCSAUDIO</constant> the -<structfield>mode</structfield> field selects <emphasis>one</emphasis> -of the <constant>VIDEO_SOUND_MONO</constant>, -<constant>VIDEO_SOUND_STEREO</constant>, -<constant>VIDEO_SOUND_LANG1</constant> or -<constant>VIDEO_SOUND_LANG2</constant> audio demodulation modes. When -the current audio standard is BTSC -<constant>VIDEO_SOUND_LANG2</constant> refers to SAP and -<constant>VIDEO_SOUND_LANG1</constant> is meaningless. Also -undocumented in the V4L specification, there is no way to query the -selected mode. On <constant>VIDIOCGAUDIO</constant> the driver returns -the <emphasis>actually received</emphasis> audio programmes in this -field. In the V4L2 API this information is stored in the &v4l2-tuner; -<structfield>rxsubchans</structfield> and -<structfield>audmode</structfield> fields, respectively. See <xref -linkend="tuner" /> for more information on tuners. Related to audio -modes &v4l2-audio; also reports if this is a mono or stereo -input, regardless if the source is a tuner.</para> - - <para>The following fields where replaced by V4L2 controls -accessible with the &VIDIOC-QUERYCTRL;, &VIDIOC-G-CTRL; and -&VIDIOC-S-CTRL; ioctls:<informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>struct -<structname>video_audio</structname></entry> - <entry>V4L2 Control ID</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry><structfield>volume</structfield></entry> - <entry><constant>V4L2_CID_AUDIO_VOLUME</constant></entry> - </row> - <row> - <entry><structfield>bass</structfield></entry> - <entry><constant>V4L2_CID_AUDIO_BASS</constant></entry> - </row> - <row> - <entry><structfield>treble</structfield></entry> - <entry><constant>V4L2_CID_AUDIO_TREBLE</constant></entry> - </row> - <row> - <entry><structfield>balance</structfield></entry> - <entry><constant>V4L2_CID_AUDIO_BALANCE</constant></entry> - </row> - </tbody> - </tgroup> - </informaltable></para> - - <para>To determine which of these controls are supported by a -driver V4L provides the <structfield>flags</structfield> -<constant>VIDEO_AUDIO_VOLUME</constant>, -<constant>VIDEO_AUDIO_BASS</constant>, -<constant>VIDEO_AUDIO_TREBLE</constant> and -<constant>VIDEO_AUDIO_BALANCE</constant>. In the V4L2 API the -&VIDIOC-QUERYCTRL; ioctl reports if the respective control is -supported. Accordingly the <constant>VIDEO_AUDIO_MUTABLE</constant> -and <constant>VIDEO_AUDIO_MUTE</constant> flags where replaced by the -boolean <constant>V4L2_CID_AUDIO_MUTE</constant> control.</para> - - <para>All V4L2 controls have a <structfield>step</structfield> -attribute replacing the struct <structname>video_audio</structname> -<structfield>step</structfield> field. The V4L audio controls are -assumed to range from 0 to 65535 with no particular reset value. The -V4L2 API permits arbitrary limits and defaults which can be queried -with the &VIDIOC-QUERYCTRL; ioctl. For general information about -controls see <xref linkend="control" />.</para> - </section> - - <section> - <title>Frame Buffer Overlay</title> - - <para>The V4L2 ioctls equivalent to -<constant>VIDIOCGFBUF</constant> and <constant>VIDIOCSFBUF</constant> -are &VIDIOC-G-FBUF; and &VIDIOC-S-FBUF;. The -<structfield>base</structfield> field of struct -<structname>video_buffer</structname> remained unchanged, except V4L2 -defines a flag to indicate non-destructive overlays instead of a -<constant>NULL</constant> pointer. All other fields moved into the -&v4l2-pix-format; <structfield>fmt</structfield> substructure of -&v4l2-framebuffer;. The <structfield>depth</structfield> field was -replaced by <structfield>pixelformat</structfield>. See <xref - linkend="pixfmt-rgb" /> for a list of RGB formats and their -respective color depths.</para> - - <para>Instead of the special ioctls -<constant>VIDIOCGWIN</constant> and <constant>VIDIOCSWIN</constant> -V4L2 uses the general-purpose data format negotiation ioctls -&VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a -&v4l2-format; as argument. Here the <structfield>win</structfield> -member of the <structfield>fmt</structfield> union is used, a -&v4l2-window;.</para> - - <para>The <structfield>x</structfield>, -<structfield>y</structfield>, <structfield>width</structfield> and -<structfield>height</structfield> fields of struct -<structname>video_window</structname> moved into &v4l2-rect; -substructure <structfield>w</structfield> of struct -<structname>v4l2_window</structname>. The -<structfield>chromakey</structfield>, -<structfield>clips</structfield>, and -<structfield>clipcount</structfield> fields remained unchanged. Struct -<structname>video_clip</structname> was renamed to &v4l2-clip;, also -containing a struct <structname>v4l2_rect</structname>, but the -semantics are still the same.</para> - - <para>The <constant>VIDEO_WINDOW_INTERLACE</constant> flag was -dropped. Instead applications must set the -<structfield>field</structfield> field to -<constant>V4L2_FIELD_ANY</constant> or -<constant>V4L2_FIELD_INTERLACED</constant>. The -<constant>VIDEO_WINDOW_CHROMAKEY</constant> flag moved into -&v4l2-framebuffer;, under the new name -<constant>V4L2_FBUF_FLAG_CHROMAKEY</constant>.</para> - - <para>In V4L, storing a bitmap pointer in -<structfield>clips</structfield> and setting -<structfield>clipcount</structfield> to -<constant>VIDEO_CLIP_BITMAP</constant> (-1) requests bitmap -clipping, using a fixed size bitmap of 1024 × 625 bits. Struct -<structname>v4l2_window</structname> has a separate -<structfield>bitmap</structfield> pointer field for this purpose and -the bitmap size is determined by <structfield>w.width</structfield> and -<structfield>w.height</structfield>.</para> - - <para>The <constant>VIDIOCCAPTURE</constant> ioctl to enable or -disable overlay was renamed to &VIDIOC-OVERLAY;.</para> - </section> - - <section> - <title>Cropping</title> - - <para>To capture only a subsection of the full picture V4L -defines the <constant>VIDIOCGCAPTURE</constant> and -<constant>VIDIOCSCAPTURE</constant> ioctls using struct -<structname>video_capture</structname>. The equivalent V4L2 ioctls are -&VIDIOC-G-CROP; and &VIDIOC-S-CROP; using &v4l2-crop;, and the related -&VIDIOC-CROPCAP; ioctl. This is a rather complex matter, see -<xref linkend="crop" /> for details.</para> - - <para>The <structfield>x</structfield>, -<structfield>y</structfield>, <structfield>width</structfield> and -<structfield>height</structfield> fields moved into &v4l2-rect; -substructure <structfield>c</structfield> of struct -<structname>v4l2_crop</structname>. The -<structfield>decimation</structfield> field was dropped. In the V4L2 -API the scaling factor is implied by the size of the cropping -rectangle and the size of the captured or overlaid image.</para> - - <para>The <constant>VIDEO_CAPTURE_ODD</constant> -and <constant>VIDEO_CAPTURE_EVEN</constant> flags to capture only the -odd or even field, respectively, were replaced by -<constant>V4L2_FIELD_TOP</constant> and -<constant>V4L2_FIELD_BOTTOM</constant> in the field named -<structfield>field</structfield> of &v4l2-pix-format; and -&v4l2-window;. These structures are used to select a capture or -overlay format with the &VIDIOC-S-FMT; ioctl.</para> - </section> - - <section> - <title>Reading Images, Memory Mapping</title> - - <section> - <title>Capturing using the read method</title> - - <para>There is no essential difference between reading images -from a V4L or V4L2 device using the &func-read; function, however V4L2 -drivers are not required to support this I/O method. Applications can -determine if the function is available with the &VIDIOC-QUERYCAP; -ioctl. All V4L2 devices exchanging data with applications must support -the &func-select; and &func-poll; functions.</para> - - <para>To select an image format and size, V4L provides the -<constant>VIDIOCSPICT</constant> and <constant>VIDIOCSWIN</constant> -ioctls. V4L2 uses the general-purpose data format negotiation ioctls -&VIDIOC-G-FMT; and &VIDIOC-S-FMT;. They take a pointer to a -&v4l2-format; as argument, here the &v4l2-pix-format; named -<structfield>pix</structfield> of its <structfield>fmt</structfield> -union is used.</para> - - <para>For more information about the V4L2 read interface see -<xref linkend="rw" />.</para> - </section> - <section> - <title>Capturing using memory mapping</title> - - <para>Applications can read from V4L devices by mapping -buffers in device memory, or more often just buffers allocated in -DMA-able system memory, into their address space. This avoids the data -copying overhead of the read method. V4L2 supports memory mapping as -well, with a few differences.</para> - - <informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>V4L</entry> - <entry>V4L2</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry></entry> - <entry>The image format must be selected before -buffers are allocated, with the &VIDIOC-S-FMT; ioctl. When no format -is selected the driver may use the last, possibly by another -application requested format.</entry> - </row> - <row> - <entry><para>Applications cannot change the number of -buffers. The it is built into the driver, unless it has a module -option to change the number when the driver module is -loaded.</para></entry> - <entry><para>The &VIDIOC-REQBUFS; ioctl allocates the -desired number of buffers, this is a required step in the initialization -sequence.</para></entry> - </row> - <row> - <entry><para>Drivers map all buffers as one contiguous -range of memory. The <constant>VIDIOCGMBUF</constant> ioctl is -available to query the number of buffers, the offset of each buffer -from the start of the virtual file, and the overall amount of memory -used, which can be used as arguments for the &func-mmap; -function.</para></entry> - <entry><para>Buffers are individually mapped. The -offset and size of each buffer can be determined with the -&VIDIOC-QUERYBUF; ioctl.</para></entry> - </row> - <row> - <entry><para>The <constant>VIDIOCMCAPTURE</constant> -ioctl prepares a buffer for capturing. It also determines the image -format for this buffer. The ioctl returns immediately, eventually with -an &EAGAIN; if no video signal had been detected. When the driver -supports more than one buffer applications can call the ioctl multiple -times and thus have multiple outstanding capture -requests.</para><para>The <constant>VIDIOCSYNC</constant> ioctl -suspends execution until a particular buffer has been -filled.</para></entry> - <entry><para>Drivers maintain an incoming and outgoing -queue. &VIDIOC-QBUF; enqueues any empty buffer into the incoming -queue. Filled buffers are dequeued from the outgoing queue with the -&VIDIOC-DQBUF; ioctl. To wait until filled buffers become available this -function, &func-select; or &func-poll; can be used. The -&VIDIOC-STREAMON; ioctl must be called once after enqueuing one or -more buffers to start capturing. Its counterpart -&VIDIOC-STREAMOFF; stops capturing and dequeues all buffers from both -queues. Applications can query the signal status, if known, with the -&VIDIOC-ENUMINPUT; ioctl.</para></entry> - </row> - </tbody> - </tgroup> - </informaltable> - - <para>For a more in-depth discussion of memory mapping and -examples, see <xref linkend="mmap" />.</para> - </section> - </section> - - <section> - <title>Reading Raw VBI Data</title> - - <para>Originally the V4L API did not specify a raw VBI capture -interface, only the device file <filename>/dev/vbi</filename> was -reserved for this purpose. The only driver supporting this interface -was the BTTV driver, de-facto defining the V4L VBI interface. Reading -from the device yields a raw VBI image with the following -parameters:<informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>&v4l2-vbi-format;</entry> - <entry>V4L, BTTV driver</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry>sampling_rate</entry> - <entry>28636363 Hz NTSC (or any other 525-line -standard); 35468950 Hz PAL and SECAM (625-line standards)</entry> - </row> - <row> - <entry>offset</entry> - <entry>?</entry> - </row> - <row> - <entry>samples_per_line</entry> - <entry>2048</entry> - </row> - <row> - <entry>sample_format</entry> - <entry>V4L2_PIX_FMT_GREY. The last four bytes (a -machine endianness integer) contain a frame counter.</entry> - </row> - <row> - <entry>start[]</entry> - <entry>10, 273 NTSC; 22, 335 PAL and SECAM</entry> - </row> - <row> - <entry>count[]</entry> - <entry><para>16, 16<footnote><para>Old driver -versions used different values, eventually the custom -<constant>BTTV_VBISIZE</constant> ioctl was added to query the -correct values.</para></footnote></para></entry> - </row> - <row> - <entry>flags</entry> - <entry>0</entry> - </row> - </tbody> - </tgroup> - </informaltable></para> - - <para>Undocumented in the V4L specification, in Linux 2.3 the -<constant>VIDIOCGVBIFMT</constant> and -<constant>VIDIOCSVBIFMT</constant> ioctls using struct -<structname>vbi_format</structname> were added to determine the VBI -image parameters. These ioctls are only partially compatible with the -V4L2 VBI interface specified in <xref linkend="raw-vbi" />.</para> - - <para>An <structfield>offset</structfield> field does not -exist, <structfield>sample_format</structfield> is supposed to be -<constant>VIDEO_PALETTE_RAW</constant>, equivalent to -<constant>V4L2_PIX_FMT_GREY</constant>. The remaining fields are -probably equivalent to &v4l2-vbi-format;.</para> - - <para>Apparently only the Zoran (ZR 36120) driver implements -these ioctls. The semantics differ from those specified for V4L2 in two -ways. The parameters are reset on &func-open; and -<constant>VIDIOCSVBIFMT</constant> always returns an &EINVAL; if the -parameters are invalid.</para> - </section> - - <section> - <title>Miscellaneous</title> - - <para>V4L2 has no equivalent of the -<constant>VIDIOCGUNIT</constant> ioctl. Applications can find the VBI -device associated with a video capture device (or vice versa) by -reopening the device and requesting VBI data. For details see -<xref linkend="open" />.</para> - - <para>No replacement exists for <constant>VIDIOCKEY</constant>, -and the V4L functions for microcode programming. A new interface for -MPEG compression and playback devices is documented in <xref - linkend="extended-controls" />.</para> - </section> - - </section> - - <section id="hist-v4l2"> - <title>Changes of the V4L2 API</title> - - <para>Soon after the V4L API was added to the kernel it was -criticised as too inflexible. In August 1998 Bill Dirks proposed a -number of improvements and began to work on documentation, example -drivers and applications. With the help of other volunteers this -eventually became the V4L2 API, not just an extension but a -replacement for the V4L API. However it took another four years and -two stable kernel releases until the new API was finally accepted for -inclusion into the kernel in its present form.</para> - - <section> - <title>Early Versions</title> - <para>1998-08-20: First version.</para> - - <para>1998-08-27: The &func-select; function was introduced.</para> - - <para>1998-09-10: New video standard interface.</para> - - <para>1998-09-18: The <constant>VIDIOC_NONCAP</constant> ioctl -was replaced by the otherwise meaningless <constant>O_TRUNC</constant> -&func-open; flag, and the aliases <constant>O_NONCAP</constant> and -<constant>O_NOIO</constant> were defined. Applications can set this -flag if they intend to access controls only, as opposed to capture -applications which need exclusive access. The -<constant>VIDEO_STD_XXX</constant> identifiers are now ordinals -instead of flags, and the <function>video_std_construct()</function> -helper function takes id and transmission arguments.</para> - - <para>1998-09-28: Revamped video standard. Made video controls -individually enumerable.</para> - - <para>1998-10-02: The <structfield>id</structfield> field was -removed from struct <structname>video_standard</structname> and the -color subcarrier fields were renamed. The &VIDIOC-QUERYSTD; ioctl was -renamed to &VIDIOC-ENUMSTD;, &VIDIOC-G-INPUT; to &VIDIOC-ENUMINPUT;. A -first draft of the Codec API was released.</para> - - <para>1998-11-08: Many minor changes. Most symbols have been -renamed. Some material changes to &v4l2-capability;.</para> - - <para>1998-11-12: The read/write directon of some ioctls was misdefined.</para> - - <para>1998-11-14: <constant>V4L2_PIX_FMT_RGB24</constant> -changed to <constant>V4L2_PIX_FMT_BGR24</constant>, and -<constant>V4L2_PIX_FMT_RGB32</constant> changed to -<constant>V4L2_PIX_FMT_BGR32</constant>. Audio controls are now -accessible with the &VIDIOC-G-CTRL; and &VIDIOC-S-CTRL; ioctls under -names starting with <constant>V4L2_CID_AUDIO</constant>. The -<constant>V4L2_MAJOR</constant> define was removed from -<filename>videodev.h</filename> since it was only used once in the -<filename>videodev</filename> kernel module. The -<constant>YUV422</constant> and <constant>YUV411</constant> planar -image formats were added.</para> - - <para>1998-11-28: A few ioctl symbols changed. Interfaces for codecs and -video output devices were added.</para> - - <para>1999-01-14: A raw VBI capture interface was added.</para> - - <para>1999-01-19: The <constant>VIDIOC_NEXTBUF</constant> ioctl - was removed.</para> - </section> - - <section> - <title>V4L2 Version 0.16 1999-01-31</title> - <para>1999-01-27: There is now one QBUF ioctl, VIDIOC_QWBUF and VIDIOC_QRBUF -are gone. VIDIOC_QBUF takes a v4l2_buffer as a parameter. Added -digital zoom (cropping) controls.</para> - </section> - - <!-- Where's 0.17? mhs couldn't find that videodev.h, perhaps Bill - forgot to bump the version number or never released it. --> - - <section> - <title>V4L2 Version 0.18 1999-03-16</title> - <para>Added a v4l to V4L2 ioctl compatibility layer to -videodev.c. Driver writers, this changes how you implement your ioctl -handler. See the Driver Writer's Guide. Added some more control id -codes.</para> - </section> - - <section> - <title>V4L2 Version 0.19 1999-06-05</title> - <para>1999-03-18: Fill in the category and catname fields of -v4l2_queryctrl objects before passing them to the driver. Required a -minor change to the VIDIOC_QUERYCTRL handlers in the sample -drivers.</para> - <para>1999-03-31: Better compatibility for v4l memory capture -ioctls. Requires changes to drivers to fully support new compatibility -features, see Driver Writer's Guide and v4l2cap.c. Added new control -IDs: V4L2_CID_HFLIP, _VFLIP. Changed V4L2_PIX_FMT_YUV422P to _YUV422P, -and _YUV411P to _YUV411P.</para> - <para>1999-04-04: Added a few more control IDs.</para> - <para>1999-04-07: Added the button control type.</para> - <para>1999-05-02: Fixed a typo in videodev.h, and added the -V4L2_CTRL_FLAG_GRAYED (later V4L2_CTRL_FLAG_GRABBED) flag.</para> - <para>1999-05-20: Definition of VIDIOC_G_CTRL was wrong causing -a malfunction of this ioctl.</para> - <para>1999-06-05: Changed the value of -V4L2_CID_WHITENESS.</para> - </section> - - <section> - <title>V4L2 Version 0.20 (1999-09-10)</title> - - <para>Version 0.20 introduced a number of changes which were -<emphasis>not backward compatible</emphasis> with 0.19 and earlier -versions. Purpose of these changes was to simplify the API, while -making it more extensible and following common Linux driver API -conventions.</para> - - <orderedlist> - <listitem> - <para>Some typos in <constant>V4L2_FMT_FLAG</constant> -symbols were fixed. &v4l2-clip; was changed for compatibility with -v4l. (1999-08-30)</para> - </listitem> - - <listitem> - <para><constant>V4L2_TUNER_SUB_LANG1</constant> was added. -(1999-09-05)</para> - </listitem> - - <listitem> - <para>All ioctl() commands that used an integer argument now -take a pointer to an integer. Where it makes sense, ioctls will return -the actual new value in the integer pointed to by the argument, a -common convention in the V4L2 API. The affected ioctls are: -VIDIOC_PREVIEW, VIDIOC_STREAMON, VIDIOC_STREAMOFF, VIDIOC_S_FREQ, -VIDIOC_S_INPUT, VIDIOC_S_OUTPUT, VIDIOC_S_EFFECT. For example -<programlisting> -err = ioctl (fd, VIDIOC_XXX, V4L2_XXX); -</programlisting> becomes <programlisting> -int a = V4L2_XXX; err = ioctl(fd, VIDIOC_XXX, &a); -</programlisting> - </para> - </listitem> - - <listitem> - <para>All the different get- and set-format commands were -swept into one &VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctl taking a union -and a type field selecting the union member as parameter. Purpose is to -simplify the API by eliminating several ioctls and to allow new and -driver private data streams without adding new ioctls.</para> - - <para>This change obsoletes the following ioctls: -<constant>VIDIOC_S_INFMT</constant>, -<constant>VIDIOC_G_INFMT</constant>, -<constant>VIDIOC_S_OUTFMT</constant>, -<constant>VIDIOC_G_OUTFMT</constant>, -<constant>VIDIOC_S_VBIFMT</constant> and -<constant>VIDIOC_G_VBIFMT</constant>. The image format structure -<structname>v4l2_format</structname> was renamed to &v4l2-pix-format;, -while &v4l2-format; is now the envelopping structure for all format -negotiations.</para> - </listitem> - - <listitem> - <para>Similar to the changes above, the -<constant>VIDIOC_G_PARM</constant> and -<constant>VIDIOC_S_PARM</constant> ioctls were merged with -<constant>VIDIOC_G_OUTPARM</constant> and -<constant>VIDIOC_S_OUTPARM</constant>. A -<structfield>type</structfield> field in the new &v4l2-streamparm; -selects the respective union member.</para> - - <para>This change obsoletes the -<constant>VIDIOC_G_OUTPARM</constant> and -<constant>VIDIOC_S_OUTPARM</constant> ioctls.</para> - </listitem> - - <listitem> - <para>Control enumeration was simplified, and two new -control flags were introduced and one dropped. The -<structfield>catname</structfield> field was replaced by a -<structfield>group</structfield> field.</para> - - <para>Drivers can now flag unsupported and temporarily -unavailable controls with <constant>V4L2_CTRL_FLAG_DISABLED</constant> -and <constant>V4L2_CTRL_FLAG_GRABBED</constant> respectively. The -<structfield>group</structfield> name indicates a possibly narrower -classification than the <structfield>category</structfield>. In other -words, there may be multiple groups within a category. Controls within -a group would typically be drawn within a group box. Controls in -different categories might have a greater separation, or may even -appear in separate windows.</para> - </listitem> - - <listitem> - <para>The &v4l2-buffer; <structfield>timestamp</structfield> -was changed to a 64 bit integer, containing the sampling or output -time of the frame in nanoseconds. Additionally timestamps will be in -absolute system time, not starting from zero at the beginning of a -stream. The data type name for timestamps is stamp_t, defined as a -signed 64-bit integer. Output devices should not send a buffer out -until the time in the timestamp field has arrived. I would like to -follow SGI's lead, and adopt a multimedia timestamping system like -their UST (Unadjusted System Time). See -http://web.archive.org/web/*/http://reality.sgi.com -/cpirazzi_engr/lg/time/intro.html. -UST uses timestamps that are 64-bit signed integers -(not struct timeval's) and given in nanosecond units. The UST clock -starts at zero when the system is booted and runs continuously and -uniformly. It takes a little over 292 years for UST to overflow. There -is no way to set the UST clock. The regular Linux time-of-day clock -can be changed periodically, which would cause errors if it were being -used for timestamping a multimedia stream. A real UST style clock will -require some support in the kernel that is not there yet. But in -anticipation, I will change the timestamp field to a 64-bit integer, -and I will change the v4l2_masterclock_gettime() function (used only -by drivers) to return a 64-bit integer.</para> - </listitem> - - <listitem> - <para>A <structfield>sequence</structfield> field was added -to &v4l2-buffer;. The <structfield>sequence</structfield> field counts -captured frames, it is ignored by output devices. When a capture -driver drops a frame, the sequence number of that frame is -skipped.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 Version 0.20 incremental changes</title> - <!-- Version number didn't change anymore, reason unknown. --> - - <para>1999-12-23: In &v4l2-vbi-format; the -<structfield>reserved1</structfield> field became -<structfield>offset</structfield>. Previously drivers were required to -clear the <structfield>reserved1</structfield> field.</para> - - <para>2000-01-13: The - <constant>V4L2_FMT_FLAG_NOT_INTERLACED</constant> flag was added.</para> - - <para>2000-07-31: The <filename>linux/poll.h</filename> header -is now included by <filename>videodev.h</filename> for compatibility -with the original <filename>videodev.h</filename> file.</para> - - <para>2000-11-20: <constant>V4L2_TYPE_VBI_OUTPUT</constant> and -<constant>V4L2_PIX_FMT_Y41P</constant> were added.</para> - - <para>2000-11-25: <constant>V4L2_TYPE_VBI_INPUT</constant> was -added.</para> - - <para>2000-12-04: A couple typos in symbol names were fixed.</para> - - <para>2001-01-18: To avoid namespace conflicts the -<constant>fourcc</constant> macro defined in the -<filename>videodev.h</filename> header file was renamed to -<constant>v4l2_fourcc</constant>.</para> - - <para>2001-01-25: A possible driver-level compatibility problem -between the <filename>videodev.h</filename> file in Linux 2.4.0 and -the <filename>videodev.h</filename> file included in the -<filename>videodevX</filename> patch was fixed. Users of an earlier -version of <filename>videodevX</filename> on Linux 2.4.0 should -recompile their V4L and V4L2 drivers.</para> - - <para>2001-01-26: A possible kernel-level incompatibility -between the <filename>videodev.h</filename> file in the -<filename>videodevX</filename> patch and the -<filename>videodev.h</filename> file in Linux 2.2.x with devfs patches -applied was fixed.</para> - - <para>2001-03-02: Certain V4L ioctls which pass data in both -direction although they are defined with read-only parameter, did not -work correctly through the backward compatibility layer. -[Solution?]</para> - - <para>2001-04-13: Big endian 16-bit RGB formats were added.</para> - - <para>2001-09-17: New YUV formats and the &VIDIOC-G-FREQUENCY; and -&VIDIOC-S-FREQUENCY; ioctls were added. (The old -<constant>VIDIOC_G_FREQ</constant> and -<constant>VIDIOC_S_FREQ</constant> ioctls did not take multiple tuners -into account.)</para> - - <para>2000-09-18: <constant>V4L2_BUF_TYPE_VBI</constant> was -added. This may <emphasis>break compatibility</emphasis> as the -&VIDIOC-G-FMT; and &VIDIOC-S-FMT; ioctls may fail now if the struct -<structname>v4l2_fmt</structname> <structfield>type</structfield> -field does not contain <constant>V4L2_BUF_TYPE_VBI</constant>. In the -documentation of the &v4l2-vbi-format; -<structfield>offset</structfield> field the ambiguous phrase "rising -edge" was changed to "leading edge".</para> - </section> - - <section> - <title>V4L2 Version 0.20 2000-11-23</title> - - <para>A number of changes were made to the raw VBI -interface.</para> - - <orderedlist> - <listitem> - <para>Figures clarifying the line numbering scheme were -added to the V4L2 API specification. The -<structfield>start</structfield>[0] and -<structfield>start</structfield>[1] fields no longer count line -numbers beginning at zero. Rationale: a) The previous definition was -unclear. b) The <structfield>start</structfield>[] values are ordinal -numbers. c) There is no point in inventing a new line numbering -scheme. We now use line number as defined by ITU-R, period. -Compatibility: Add one to the start values. Applications depending on -the previous semantics may not function correctly.</para> - </listitem> - - <listitem> - <para>The restriction "count[0] > 0 and count[1] > 0" -has been relaxed to "(count[0] + count[1]) > 0". Rationale: -Drivers may allocate resources at scan line granularity and some data -services are transmitted only on the first field. The comment that -both <structfield>count</structfield> values will usually be equal is -misleading and pointless and has been removed. This change -<emphasis>breaks compatibility</emphasis> with earlier versions: -Drivers may return EINVAL, applications may not function -correctly.</para> - </listitem> - - <listitem> - <para>Drivers are again permitted to return negative -(unknown) start values as proposed earlier. Why this feature was -dropped is unclear. This change may <emphasis>break -compatibility</emphasis> with applications depending on the start -values being positive. The use of <constant>EBUSY</constant> and -<constant>EINVAL</constant> error codes with the &VIDIOC-S-FMT; ioctl -was clarified. The &EBUSY; was finally documented, and the -<structfield>reserved2</structfield> field which was previously -mentioned only in the <filename>videodev.h</filename> header -file.</para> - </listitem> - - <listitem> - <para>New buffer types -<constant>V4L2_TYPE_VBI_INPUT</constant> and -<constant>V4L2_TYPE_VBI_OUTPUT</constant> were added. The former is an -alias for the old <constant>V4L2_TYPE_VBI</constant>, the latter was -missing in the <filename>videodev.h</filename> file.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 Version 0.20 2002-07-25</title> - <para>Added sliced VBI interface proposal.</para> - </section> - - <section> - <title>V4L2 in Linux 2.5.46, 2002-10</title> - - <para>Around October-November 2002, prior to an announced -feature freeze of Linux 2.5, the API was revised, drawing from -experience with V4L2 0.20. This unnamed version was finally merged -into Linux 2.5.46.</para> - - <orderedlist> - <listitem> - <para>As specified in <xref linkend="related" />, drivers -must make related device functions available under all minor device -numbers.</para> - </listitem> - - <listitem> - <para>The &func-open; function requires access mode -<constant>O_RDWR</constant> regardless of the device type. All V4L2 -drivers exchanging data with applications must support the -<constant>O_NONBLOCK</constant> flag. The <constant>O_NOIO</constant> -flag, a V4L2 symbol which aliased the meaningless -<constant>O_TRUNC</constant> to indicate accesses without data -exchange (panel applications) was dropped. Drivers must stay in "panel -mode" until the application attempts to initiate a data exchange, see -<xref linkend="open" />.</para> - </listitem> - - <listitem> - <para>The &v4l2-capability; changed dramatically. Note that -also the size of the structure changed, which is encoded in the ioctl -request code, thus older V4L2 devices will respond with an &EINVAL; to -the new &VIDIOC-QUERYCAP; ioctl.</para> - - <para>There are new fields to identify the driver, a new RDS -device function <constant>V4L2_CAP_RDS_CAPTURE</constant>, the -<constant>V4L2_CAP_AUDIO</constant> flag indicates if the device has -any audio connectors, another I/O capability -<constant>V4L2_CAP_ASYNCIO</constant> can be flagged. In response to -these changes the <structfield>type</structfield> field became a bit -set and was merged into the <structfield>flags</structfield> field. -<constant>V4L2_FLAG_TUNER</constant> was renamed to -<constant>V4L2_CAP_TUNER</constant>, -<constant>V4L2_CAP_VIDEO_OVERLAY</constant> replaced -<constant>V4L2_FLAG_PREVIEW</constant> and -<constant>V4L2_CAP_VBI_CAPTURE</constant> and -<constant>V4L2_CAP_VBI_OUTPUT</constant> replaced -<constant>V4L2_FLAG_DATA_SERVICE</constant>. -<constant>V4L2_FLAG_READ</constant> and -<constant>V4L2_FLAG_WRITE</constant> were merged into -<constant>V4L2_CAP_READWRITE</constant>.</para> - - <para>The redundant fields -<structfield>inputs</structfield>, <structfield>outputs</structfield> -and <structfield>audios</structfield> were removed. These properties -can be determined as described in <xref linkend="video" /> and <xref -linkend="audio" />.</para> - - <para>The somewhat volatile and therefore barely useful -fields <structfield>maxwidth</structfield>, -<structfield>maxheight</structfield>, -<structfield>minwidth</structfield>, -<structfield>minheight</structfield>, -<structfield>maxframerate</structfield> were removed. This information -is available as described in <xref linkend="format" /> and -<xref linkend="standard" />.</para> - - <para><constant>V4L2_FLAG_SELECT</constant> was removed. We -believe the select() function is important enough to require support -of it in all V4L2 drivers exchanging data with applications. The -redundant <constant>V4L2_FLAG_MONOCHROME</constant> flag was removed, -this information is available as described in <xref - linkend="format" />.</para> - </listitem> - - <listitem> - <para>In &v4l2-input; the -<structfield>assoc_audio</structfield> field and the -<structfield>capability</structfield> field and its only flag -<constant>V4L2_INPUT_CAP_AUDIO</constant> was replaced by the new -<structfield>audioset</structfield> field. Instead of linking one -video input to one audio input this field reports all audio inputs -this video input combines with.</para> - - <para>New fields are <structfield>tuner</structfield> -(reversing the former link from tuners to video inputs), -<structfield>std</structfield> and -<structfield>status</structfield>.</para> - - <para>Accordingly &v4l2-output; lost its -<structfield>capability</structfield> and -<structfield>assoc_audio</structfield> fields. -<structfield>audioset</structfield>, -<structfield>modulator</structfield> and -<structfield>std</structfield> where added instead.</para> - </listitem> - - <listitem> - <para>The &v4l2-audio; field -<structfield>audio</structfield> was renamed to -<structfield>index</structfield>, for consistency with other -structures. A new capability flag -<constant>V4L2_AUDCAP_STEREO</constant> was added to indicated if the -audio input in question supports stereo sound. -<constant>V4L2_AUDCAP_EFFECTS</constant> and the corresponding -<constant>V4L2_AUDMODE</constant> flags where removed. This can be -easily implemented using controls. (However the same applies to AVL -which is still there.)</para> - - <para>Again for consistency the &v4l2-audioout; field -<structfield>audio</structfield> was renamed to -<structfield>index</structfield>.</para> - </listitem> - - <listitem> - <para>The &v4l2-tuner; -<structfield>input</structfield> field was replaced by an -<structfield>index</structfield> field, permitting devices with -multiple tuners. The link between video inputs and tuners is now -reversed, inputs point to their tuner. The -<structfield>std</structfield> substructure became a -simple set (more about this below) and moved into &v4l2-input;. A -<structfield>type</structfield> field was added.</para> - - <para>Accordingly in &v4l2-modulator; the -<structfield>output</structfield> was replaced by an -<structfield>index</structfield> field.</para> - - <para>In &v4l2-frequency; the -<structfield>port</structfield> field was replaced by a -<structfield>tuner</structfield> field containing the respective tuner -or modulator index number. A tuner <structfield>type</structfield> -field was added and the <structfield>reserved</structfield> field -became larger for future extensions (satellite tuners in -particular).</para> - </listitem> - - <listitem> - <para>The idea of completely transparent video standards was -dropped. Experience showed that applications must be able to work with -video standards beyond presenting the user a menu. Instead of -enumerating supported standards with an ioctl applications can now -refer to standards by &v4l2-std-id; and symbols defined in the -<filename>videodev2.h</filename> header file. For details see <xref - linkend="standard" />. The &VIDIOC-G-STD; and -&VIDIOC-S-STD; now take a pointer to this type as argument. -&VIDIOC-QUERYSTD; was added to autodetect the received standard, if -the hardware has this capability. In &v4l2-standard; an -<structfield>index</structfield> field was added for &VIDIOC-ENUMSTD;. -A &v4l2-std-id; field named <structfield>id</structfield> was added as -machine readable identifier, also replacing the -<structfield>transmission</structfield> field. The misleading -<structfield>framerate</structfield> field was renamed -to <structfield>frameperiod</structfield>. The now obsolete -<structfield>colorstandard</structfield> information, originally -needed to distguish between variations of standards, were -removed.</para> - - <para>Struct <structname>v4l2_enumstd</structname> ceased to -be. &VIDIOC-ENUMSTD; now takes a pointer to a &v4l2-standard; -directly. The information which standards are supported by a -particular video input or output moved into &v4l2-input; and -&v4l2-output; fields named <structfield>std</structfield>, -respectively.</para> - </listitem> - - <listitem> - <para>The &v4l2-queryctrl; fields -<structfield>category</structfield> and -<structfield>group</structfield> did not catch on and/or were not -implemented as expected and therefore removed.</para> - </listitem> - - <listitem> - <para>The &VIDIOC-TRY-FMT; ioctl was added to negotiate data -formats as with &VIDIOC-S-FMT;, but without the overhead of -programming the hardware and regardless of I/O in progress.</para> - - <para>In &v4l2-format; the <structfield>fmt</structfield> -union was extended to contain &v4l2-window;. All image format -negotiations are now possible with <constant>VIDIOC_G_FMT</constant>, -<constant>VIDIOC_S_FMT</constant> and -<constant>VIDIOC_TRY_FMT</constant>; ioctl. The -<constant>VIDIOC_G_WIN</constant> and -<constant>VIDIOC_S_WIN</constant> ioctls to prepare for a video -overlay were removed. The <structfield>type</structfield> field -changed to type &v4l2-buf-type; and the buffer type names changed as -follows.<informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>Old defines</entry> - <entry>&v4l2-buf-type;</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry><constant>V4L2_BUF_TYPE_CAPTURE</constant></entry> - <entry><constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant></entry> - </row> - <row> - <entry><constant>V4L2_BUF_TYPE_CODECIN</constant></entry> - <entry>Omitted for now</entry> - </row> - <row> - <entry><constant>V4L2_BUF_TYPE_CODECOUT</constant></entry> - <entry>Omitted for now</entry> - </row> - <row> - <entry><constant>V4L2_BUF_TYPE_EFFECTSIN</constant></entry> - <entry>Omitted for now</entry> - </row> - <row> - <entry><constant>V4L2_BUF_TYPE_EFFECTSIN2</constant></entry> - <entry>Omitted for now</entry> - </row> - <row> - <entry><constant>V4L2_BUF_TYPE_EFFECTSOUT</constant></entry> - <entry>Omitted for now</entry> - </row> - <row> - <entry><constant>V4L2_BUF_TYPE_VIDEOOUT</constant></entry> - <entry><constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant></entry> - </row> - <row> - <entry><constant>-</constant></entry> - <entry><constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant></entry> - </row> - <row> - <entry><constant>-</constant></entry> - <entry><constant>V4L2_BUF_TYPE_VBI_CAPTURE</constant></entry> - </row> - <row> - <entry><constant>-</constant></entry> - <entry><constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant></entry> - </row> - <row> - <entry><constant>-</constant></entry> - <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant></entry> - </row> - <row> - <entry><constant>-</constant></entry> - <entry><constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant></entry> - </row> - <row> - <entry><constant>V4L2_BUF_TYPE_PRIVATE_BASE</constant></entry> - <entry><constant>V4L2_BUF_TYPE_PRIVATE</constant> (but this is deprecated)</entry> - </row> - </tbody> - </tgroup> - </informaltable></para> - </listitem> - - <listitem> - <para>In &v4l2-fmtdesc; a &v4l2-buf-type; field named -<structfield>type</structfield> was added as in &v4l2-format;. The -<constant>VIDIOC_ENUM_FBUFFMT</constant> ioctl is no longer needed and -was removed. These calls can be replaced by &VIDIOC-ENUM-FMT; with -type <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para> - </listitem> - - <listitem> - <para>In &v4l2-pix-format; the -<structfield>depth</structfield> field was removed, assuming -applications which recognize the format by its four-character-code -already know the color depth, and others do not care about it. The -same rationale lead to the removal of the -<constant>V4L2_FMT_FLAG_COMPRESSED</constant> flag. The -<constant>V4L2_FMT_FLAG_SWCONVECOMPRESSED</constant> flag was removed -because drivers are not supposed to convert images in kernel space. A -user library of conversion functions should be provided instead. The -<constant>V4L2_FMT_FLAG_BYTESPERLINE</constant> flag was redundant. -Applications can set the <structfield>bytesperline</structfield> field -to zero to get a reasonable default. Since the remaining flags were -replaced as well, the <structfield>flags</structfield> field itself -was removed.</para> - <para>The interlace flags were replaced by a &v4l2-field; -value in a newly added <structfield>field</structfield> -field.<informaltable> - <tgroup cols="2"> - <thead> - <row> - <entry>Old flag</entry> - <entry>&v4l2-field;</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry><constant>V4L2_FMT_FLAG_NOT_INTERLACED</constant></entry> - <entry>?</entry> - </row> - <row> - <entry><constant>V4L2_FMT_FLAG_INTERLACED</constant> -= <constant>V4L2_FMT_FLAG_COMBINED</constant></entry> - <entry><constant>V4L2_FIELD_INTERLACED</constant></entry> - </row> - <row> - <entry><constant>V4L2_FMT_FLAG_TOPFIELD</constant> -= <constant>V4L2_FMT_FLAG_ODDFIELD</constant></entry> - <entry><constant>V4L2_FIELD_TOP</constant></entry> - </row> - <row> - <entry><constant>V4L2_FMT_FLAG_BOTFIELD</constant> -= <constant>V4L2_FMT_FLAG_EVENFIELD</constant></entry> - <entry><constant>V4L2_FIELD_BOTTOM</constant></entry> - </row> - <row> - <entry><constant>-</constant></entry> - <entry><constant>V4L2_FIELD_SEQ_TB</constant></entry> - </row> - <row> - <entry><constant>-</constant></entry> - <entry><constant>V4L2_FIELD_SEQ_BT</constant></entry> - </row> - <row> - <entry><constant>-</constant></entry> - <entry><constant>V4L2_FIELD_ALTERNATE</constant></entry> - </row> - </tbody> - </tgroup> - </informaltable></para> - - <para>The color space flags were replaced by a -&v4l2-colorspace; value in a newly added -<structfield>colorspace</structfield> field, where one of -<constant>V4L2_COLORSPACE_SMPTE170M</constant>, -<constant>V4L2_COLORSPACE_BT878</constant>, -<constant>V4L2_COLORSPACE_470_SYSTEM_M</constant> or -<constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant> replaces -<constant>V4L2_FMT_CS_601YUV</constant>.</para> - </listitem> - - <listitem> - <para>In &v4l2-requestbuffers; the -<structfield>type</structfield> field was properly defined as -&v4l2-buf-type;. Buffer types changed as mentioned above. A new -<structfield>memory</structfield> field of type &v4l2-memory; was -added to distinguish between I/O methods using buffers allocated -by the driver or the application. See <xref linkend="io" /> for -details.</para> - </listitem> - - <listitem> - <para>In &v4l2-buffer; the <structfield>type</structfield> -field was properly defined as &v4l2-buf-type;. Buffer types changed as -mentioned above. A <structfield>field</structfield> field of type -&v4l2-field; was added to indicate if a buffer contains a top or -bottom field. The old field flags were removed. Since no unadjusted -system time clock was added to the kernel as planned, the -<structfield>timestamp</structfield> field changed back from type -stamp_t, an unsigned 64 bit integer expressing the sample time in -nanoseconds, to struct <structname>timeval</structname>. With the -addition of a second memory mapping method the -<structfield>offset</structfield> field moved into union -<structfield>m</structfield>, and a new -<structfield>memory</structfield> field of type &v4l2-memory; was -added to distinguish between I/O methods. See <xref linkend="io" /> -for details.</para> - - <para>The <constant>V4L2_BUF_REQ_CONTIG</constant> -flag was used by the V4L compatibility layer, after changes to this -code it was no longer needed. The -<constant>V4L2_BUF_ATTR_DEVICEMEM</constant> flag would indicate if -the buffer was indeed allocated in device memory rather than DMA-able -system memory. It was barely useful and so was removed.</para> - </listitem> - - <listitem> - <para>In &v4l2-framebuffer; the -<structfield>base[3]</structfield> array anticipating double- and -triple-buffering in off-screen video memory, however without defining -a synchronization mechanism, was replaced by a single pointer. The -<constant>V4L2_FBUF_CAP_SCALEUP</constant> and -<constant>V4L2_FBUF_CAP_SCALEDOWN</constant> flags were removed. -Applications can determine this capability more accurately using the -new cropping and scaling interface. The -<constant>V4L2_FBUF_CAP_CLIPPING</constant> flag was replaced by -<constant>V4L2_FBUF_CAP_LIST_CLIPPING</constant> and -<constant>V4L2_FBUF_CAP_BITMAP_CLIPPING</constant>.</para> - </listitem> - - <listitem> - <para>In &v4l2-clip; the <structfield>x</structfield>, -<structfield>y</structfield>, <structfield>width</structfield> and -<structfield>height</structfield> field moved into a -<structfield>c</structfield> substructure of type &v4l2-rect;. The -<structfield>x</structfield> and <structfield>y</structfield> fields -were renamed to <structfield>left</structfield> and -<structfield>top</structfield>, &ie; offsets to a context dependent -origin.</para> - </listitem> - - <listitem> - <para>In &v4l2-window; the <structfield>x</structfield>, -<structfield>y</structfield>, <structfield>width</structfield> and -<structfield>height</structfield> field moved into a -<structfield>w</structfield> substructure as above. A -<structfield>field</structfield> field of type %v4l2-field; was added -to distinguish between field and frame (interlaced) overlay.</para> - </listitem> - - <listitem> - <para>The digital zoom interface, including struct -<structname>v4l2_zoomcap</structname>, struct -<structname>v4l2_zoom</structname>, -<constant>V4L2_ZOOM_NONCAP</constant> and -<constant>V4L2_ZOOM_WHILESTREAMING</constant> was replaced by a new -cropping and scaling interface. The previously unused struct -<structname>v4l2_cropcap</structname> and -<structname>v4l2_crop</structname> where redefined for this purpose. -See <xref linkend="crop" /> for details.</para> - </listitem> - - <listitem> - <para>In &v4l2-vbi-format; the -<structfield>SAMPLE_FORMAT</structfield> field now contains a -four-character-code as used to identify video image formats and -<constant>V4L2_PIX_FMT_GREY</constant> replaces the -<constant>V4L2_VBI_SF_UBYTE</constant> define. The -<structfield>reserved</structfield> field was extended.</para> - </listitem> - - <listitem> - <para>In &v4l2-captureparm; the type of the -<structfield>timeperframe</structfield> field changed from unsigned -long to &v4l2-fract;. This allows the accurate expression of multiples -of the NTSC-M frame rate 30000 / 1001. A new field -<structfield>readbuffers</structfield> was added to control the driver -behaviour in read I/O mode.</para> - - <para>Similar changes were made to &v4l2-outputparm;.</para> - </listitem> - - <listitem> - <para>The struct <structname>v4l2_performance</structname> -and <constant>VIDIOC_G_PERF</constant> ioctl were dropped. Except when -using the <link linkend="rw">read/write I/O method</link>, which is -limited anyway, this information is already available to -applications.</para> - </listitem> - - <listitem> - <para>The example transformation from RGB to YCbCr color -space in the old V4L2 documentation was inaccurate, this has been -corrected in <xref linkend="pixfmt" />.<!-- 0.5670G should be -0.587, and 127/112 != 255/224 --></para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 2003-06-19</title> - - <orderedlist> - <listitem> - <para>A new capability flag -<constant>V4L2_CAP_RADIO</constant> was added for radio devices. Prior -to this change radio devices would identify solely by having exactly one -tuner whose type field reads <constant>V4L2_TUNER_RADIO</constant>.</para> - </listitem> - - <listitem> - <para>An optional driver access priority mechanism was -added, see <xref linkend="app-pri" /> for details.</para> - </listitem> - - <listitem> - <para>The audio input and output interface was found to be -incomplete.</para> - <para>Previously the &VIDIOC-G-AUDIO; -ioctl would enumerate the available audio inputs. An ioctl to -determine the current audio input, if more than one combines with the -current video input, did not exist. So -<constant>VIDIOC_G_AUDIO</constant> was renamed to -<constant>VIDIOC_G_AUDIO_OLD</constant>, this ioctl was removed on -Kernel 2.6.39. The &VIDIOC-ENUMAUDIO; ioctl was added to enumerate -audio inputs, while &VIDIOC-G-AUDIO; now reports the current audio -input.</para> - <para>The same changes were made to &VIDIOC-G-AUDOUT; and -&VIDIOC-ENUMAUDOUT;.</para> - <para>Until further the "videodev" module will automatically -translate between the old and new ioctls, but drivers and applications -must be updated to successfully compile again.</para> - </listitem> - - <listitem> - <para>The &VIDIOC-OVERLAY; ioctl was incorrectly defined with -write-read parameter. It was changed to write-only, while the write-read -version was renamed to <constant>VIDIOC_OVERLAY_OLD</constant>. The old -ioctl was removed on Kernel 2.6.39. Until further the "videodev" -kernel module will automatically translate to the new version, so drivers -must be recompiled, but not applications.</para> - </listitem> - - <listitem> - <para><xref linkend="overlay" /> incorrectly stated that -clipping rectangles define regions where the video can be seen. -Correct is that clipping rectangles define regions where -<emphasis>no</emphasis> video shall be displayed and so the graphics -surface can be seen.</para> - </listitem> - - <listitem> - <para>The &VIDIOC-S-PARM; and &VIDIOC-S-CTRL; ioctls were -defined with write-only parameter, inconsistent with other ioctls -modifying their argument. They were changed to write-read, while a -<constant>_OLD</constant> suffix was added to the write-only versions. -The old ioctls were removed on Kernel 2.6.39. Drivers and -applications assuming a constant parameter need an update.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 2003-11-05</title> - <orderedlist> - <listitem> - <para>In <xref linkend="pixfmt-rgb" /> the following pixel -formats were incorrectly transferred from Bill Dirks' V4L2 -specification. Descriptions below refer to bytes in memory, in -ascending address order.<informaltable> - <tgroup cols="3"> - <thead> - <row> - <entry>Symbol</entry> - <entry>In this document prior to revision -0.5</entry> - <entry>Corrected</entry> - </row> - </thead> - <tbody valign="top"> - <row> - <entry><constant>V4L2_PIX_FMT_RGB24</constant></entry> - <entry>B, G, R</entry> - <entry>R, G, B</entry> - </row> - <row> - <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry> - <entry>R, G, B</entry> - <entry>B, G, R</entry> - </row> - <row> - <entry><constant>V4L2_PIX_FMT_RGB32</constant></entry> - <entry>B, G, R, X</entry> - <entry>R, G, B, X</entry> - </row> - <row> - <entry><constant>V4L2_PIX_FMT_BGR32</constant></entry> - <entry>R, G, B, X</entry> - <entry>B, G, R, X</entry> - </row> - </tbody> - </tgroup> - </informaltable> The -<constant>V4L2_PIX_FMT_BGR24</constant> example was always -correct.</para> - <para>In <xref linkend="v4l-image-properties" /> the mapping -of the V4L <constant>VIDEO_PALETTE_RGB24</constant> and -<constant>VIDEO_PALETTE_RGB32</constant> formats to V4L2 pixel formats -was accordingly corrected.</para> - </listitem> - - <listitem> - <para>Unrelated to the fixes above, drivers may still -interpret some V4L2 RGB pixel formats differently. These issues have -yet to be addressed, for details see <xref - linkend="pixfmt-rgb" />.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.6, 2004-05-09</title> - <orderedlist> - <listitem> - <para>The &VIDIOC-CROPCAP; ioctl was incorrectly defined -with read-only parameter. It is now defined as write-read ioctl, while -the read-only version was renamed to -<constant>VIDIOC_CROPCAP_OLD</constant>. The old ioctl was removed -on Kernel 2.6.39.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.8</title> - <orderedlist> - <listitem> - <para>A new field <structfield>input</structfield> (former -<structfield>reserved[0]</structfield>) was added to the &v4l2-buffer; -structure. Purpose of this field is to alternate between video inputs -(⪚ cameras) in step with the video capturing process. This function -must be enabled with the new <constant>V4L2_BUF_FLAG_INPUT</constant> -flag. The <structfield>flags</structfield> field is no longer -read-only.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 spec erratum 2004-08-01</title> - - <orderedlist> - <listitem> - <para>The return value of the -<xref linkend="func-open" /> function was incorrectly documented.</para> - </listitem> - - <listitem> - <para>Audio output ioctls end in -AUDOUT, not -AUDIOOUT.</para> - </listitem> - - <listitem> - <para>In the Current Audio Input example the -<constant>VIDIOC_G_AUDIO</constant> ioctl took the wrong -argument.</para> - </listitem> - - <listitem> - <para>The documentation of the &VIDIOC-QBUF; and -&VIDIOC-DQBUF; ioctls did not mention the &v4l2-buffer; -<structfield>memory</structfield> field. It was also missing from -examples. Also on the <constant>VIDIOC_DQBUF</constant> page the &EIO; -was not documented.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.14</title> - <orderedlist> - <listitem> - <para>A new sliced VBI interface was added. It is documented -in <xref linkend="sliced" /> and replaces the interface first -proposed in V4L2 specification 0.8.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.15</title> - <orderedlist> - <listitem> - <para>The &VIDIOC-LOG-STATUS; ioctl was added.</para> - </listitem> - - <listitem> - <para>New video standards -<constant>V4L2_STD_NTSC_443</constant>, -<constant>V4L2_STD_SECAM_LC</constant>, -<constant>V4L2_STD_SECAM_DK</constant> (a set of SECAM D, K and K1), -and <constant>V4L2_STD_ATSC</constant> (a set of -<constant>V4L2_STD_ATSC_8_VSB</constant> and -<constant>V4L2_STD_ATSC_16_VSB</constant>) were defined. Note the -<constant>V4L2_STD_525_60</constant> set now includes -<constant>V4L2_STD_NTSC_443</constant>. See also <xref - linkend="v4l2-std-id" />.</para> - </listitem> - - <listitem> - <para>The <constant>VIDIOC_G_COMP</constant> and -<constant>VIDIOC_S_COMP</constant> ioctl were renamed to -<constant>VIDIOC_G_MPEGCOMP</constant> and -<constant>VIDIOC_S_MPEGCOMP</constant> respectively. Their argument -was replaced by a struct -<structname>v4l2_mpeg_compression</structname> pointer. (The -<constant>VIDIOC_G_MPEGCOMP</constant> and -<constant>VIDIOC_S_MPEGCOMP</constant> ioctls where removed in Linux -2.6.25.)</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 spec erratum 2005-11-27</title> - <para>The capture example in <xref linkend="capture-example" /> -called the &VIDIOC-S-CROP; ioctl without checking if cropping is -supported. In the video standard selection example in -<xref linkend="standard" /> the &VIDIOC-S-STD; call used the wrong -argument type.</para> - </section> - - <section> - <title>V4L2 spec erratum 2006-01-10</title> - <orderedlist> - <listitem> - <para>The <constant>V4L2_IN_ST_COLOR_KILL</constant> flag in -&v4l2-input; not only indicates if the color killer is enabled, but -also if it is active. (The color killer disables color decoding when -it detects no color in the video signal to improve the image -quality.)</para> - </listitem> - - <listitem> - <para>&VIDIOC-S-PARM; is a write-read ioctl, not write-only as -stated on its reference page. The ioctl changed in 2003 as noted above.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 spec erratum 2006-02-03</title> - <orderedlist> - <listitem> - <para>In &v4l2-captureparm; and &v4l2-outputparm; the -<structfield>timeperframe</structfield> field gives the time in -seconds, not microseconds.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 spec erratum 2006-02-04</title> - <orderedlist> - <listitem> - <para>The <structfield>clips</structfield> field in -&v4l2-window; must point to an array of &v4l2-clip;, not a linked -list, because drivers ignore the struct -<structname>v4l2_clip</structname>.<structfield>next</structfield> -pointer.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.17</title> - <orderedlist> - <listitem> - <para>New video standard macros were added: -<constant>V4L2_STD_NTSC_M_KR</constant> (NTSC M South Korea), and the -sets <constant>V4L2_STD_MN</constant>, -<constant>V4L2_STD_B</constant>, <constant>V4L2_STD_GH</constant> and -<constant>V4L2_STD_DK</constant>. The -<constant>V4L2_STD_NTSC</constant> and -<constant>V4L2_STD_SECAM</constant> sets now include -<constant>V4L2_STD_NTSC_M_KR</constant> and -<constant>V4L2_STD_SECAM_LC</constant> respectively.</para> - </listitem> - - <listitem> - <para>A new <constant>V4L2_TUNER_MODE_LANG1_LANG2</constant> -was defined to record both languages of a bilingual program. The -use of <constant>V4L2_TUNER_MODE_STEREO</constant> for this purpose -is deprecated now. See the &VIDIOC-G-TUNER; section for -details.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 spec erratum 2006-09-23 (Draft 0.15)</title> - <orderedlist> - <listitem> - <para>In various places -<constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> and -<constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant> of the sliced VBI -interface were not mentioned along with other buffer types.</para> - </listitem> - - <listitem> - <para>In <xref linkend="vidioc-g-audio" /> it was clarified -that the &v4l2-audio; <structfield>mode</structfield> field is a flags -field.</para> - </listitem> - - <listitem> - <para><xref linkend="vidioc-querycap" /> did not mention the -sliced VBI and radio capability flags.</para> - </listitem> - - <listitem> - <para>In <xref linkend="vidioc-g-frequency" /> it was -clarified that applications must initialize the tuner -<structfield>type</structfield> field of &v4l2-frequency; before -calling &VIDIOC-S-FREQUENCY;.</para> - </listitem> - - <listitem> - <para>The <structfield>reserved</structfield> array -in &v4l2-requestbuffers; has 2 elements, not 32.</para> - </listitem> - - <listitem> - <para>In <xref linkend="output" /> and <xref - linkend="raw-vbi" /> the device file names -<filename>/dev/vout</filename> which never caught on were replaced -by <filename>/dev/video</filename>.</para> - </listitem> - - <listitem> - <para>With Linux 2.6.15 the possible range for VBI device minor -numbers was extended from 224-239 to 224-255. Accordingly device file names -<filename>/dev/vbi0</filename> to <filename>/dev/vbi31</filename> are -possible now.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.18</title> - <orderedlist> - <listitem> - <para>New ioctls &VIDIOC-G-EXT-CTRLS;, &VIDIOC-S-EXT-CTRLS; -and &VIDIOC-TRY-EXT-CTRLS; were added, a flag to skip unsupported -controls with &VIDIOC-QUERYCTRL;, new control types -<constant>V4L2_CTRL_TYPE_INTEGER64</constant> and -<constant>V4L2_CTRL_TYPE_CTRL_CLASS</constant> (<xref - linkend="v4l2-ctrl-type" />), and new control flags -<constant>V4L2_CTRL_FLAG_READ_ONLY</constant>, -<constant>V4L2_CTRL_FLAG_UPDATE</constant>, -<constant>V4L2_CTRL_FLAG_INACTIVE</constant> and -<constant>V4L2_CTRL_FLAG_SLIDER</constant> (<xref - linkend="control-flags" />). See <xref - linkend="extended-controls" /> for details.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.19</title> - <orderedlist> - <listitem> - <para>In &v4l2-sliced-vbi-cap; a buffer type field was added -replacing a reserved field. Note on architectures where the size of -enum types differs from int types the size of the structure changed. -The &VIDIOC-G-SLICED-VBI-CAP; ioctl was redefined from being read-only -to write-read. Applications must initialize the type field and clear -the reserved fields now. These changes may <emphasis>break the -compatibility</emphasis> with older drivers and applications.</para> - </listitem> - - <listitem> - <para>The ioctls &VIDIOC-ENUM-FRAMESIZES; and -&VIDIOC-ENUM-FRAMEINTERVALS; were added.</para> - </listitem> - - <listitem> - <para>A new pixel format <constant>V4L2_PIX_FMT_RGB444</constant> (<xref -linkend="rgb-formats" />) was added.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 spec erratum 2006-10-12 (Draft 0.17)</title> - <orderedlist> - <listitem> - <para><constant>V4L2_PIX_FMT_HM12</constant> (<xref -linkend="reserved-formats" />) is a YUV 4:2:0, not 4:2:2 format.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.21</title> - <orderedlist> - <listitem> - <para>The <filename>videodev2.h</filename> header file is -now dual licensed under GNU General Public License version two or -later, and under a 3-clause BSD-style license.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.22</title> - <orderedlist> - <listitem> - <para>Two new field orders - <constant>V4L2_FIELD_INTERLACED_TB</constant> and - <constant>V4L2_FIELD_INTERLACED_BT</constant> were - added. See <xref linkend="v4l2-field" /> for details.</para> - </listitem> - - <listitem> - <para>Three new clipping/blending methods with a global or -straight or inverted local alpha value were added to the video overlay -interface. See the description of the &VIDIOC-G-FBUF; and -&VIDIOC-S-FBUF; ioctls for details.</para> - <para>A new <structfield>global_alpha</structfield> field -was added to <link -linkend="v4l2-window"><structname>v4l2_window</structname></link>, -extending the structure. This may <emphasis>break -compatibility</emphasis> with applications using a struct -<structname>v4l2_window</structname> directly. However the <link -linkend="vidioc-g-fmt">VIDIOC_G/S/TRY_FMT</link> ioctls, which take a -pointer to a <link linkend="v4l2-format">v4l2_format</link> parent -structure with padding bytes at the end, are not affected.</para> - </listitem> - - <listitem> - <para>The format of the <structfield>chromakey</structfield> -field in &v4l2-window; changed from "host order RGB32" to a pixel -value in the same format as the framebuffer. This may <emphasis>break -compatibility</emphasis> with existing applications. Drivers -supporting the "host order RGB32" format are not known.</para> - </listitem> - - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.24</title> - <orderedlist> - <listitem> - <para>The pixel formats -<constant>V4L2_PIX_FMT_PAL8</constant>, -<constant>V4L2_PIX_FMT_YUV444</constant>, -<constant>V4L2_PIX_FMT_YUV555</constant>, -<constant>V4L2_PIX_FMT_YUV565</constant> and -<constant>V4L2_PIX_FMT_YUV32</constant> were added.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.25</title> - <orderedlist> - <listitem> - <para>The pixel formats <link linkend="V4L2-PIX-FMT-Y16"> -<constant>V4L2_PIX_FMT_Y16</constant></link> and <link -linkend="V4L2-PIX-FMT-SBGGR16"> -<constant>V4L2_PIX_FMT_SBGGR16</constant></link> were added.</para> - </listitem> - <listitem> - <para>New <link linkend="control">controls</link> -<constant>V4L2_CID_POWER_LINE_FREQUENCY</constant>, -<constant>V4L2_CID_HUE_AUTO</constant>, -<constant>V4L2_CID_WHITE_BALANCE_TEMPERATURE</constant>, -<constant>V4L2_CID_SHARPNESS</constant> and -<constant>V4L2_CID_BACKLIGHT_COMPENSATION</constant> were added. The -controls <constant>V4L2_CID_BLACK_LEVEL</constant>, -<constant>V4L2_CID_WHITENESS</constant>, -<constant>V4L2_CID_HCENTER</constant> and -<constant>V4L2_CID_VCENTER</constant> were deprecated. -</para> - </listitem> - <listitem> - <para>A <link linkend="camera-controls">Camera controls -class</link> was added, with the new controls -<constant>V4L2_CID_EXPOSURE_AUTO</constant>, -<constant>V4L2_CID_EXPOSURE_ABSOLUTE</constant>, -<constant>V4L2_CID_EXPOSURE_AUTO_PRIORITY</constant>, -<constant>V4L2_CID_PAN_RELATIVE</constant>, -<constant>V4L2_CID_TILT_RELATIVE</constant>, -<constant>V4L2_CID_PAN_RESET</constant>, -<constant>V4L2_CID_TILT_RESET</constant>, -<constant>V4L2_CID_PAN_ABSOLUTE</constant>, -<constant>V4L2_CID_TILT_ABSOLUTE</constant>, -<constant>V4L2_CID_FOCUS_ABSOLUTE</constant>, -<constant>V4L2_CID_FOCUS_RELATIVE</constant> and -<constant>V4L2_CID_FOCUS_AUTO</constant>.</para> - </listitem> - <listitem> - <para>The <constant>VIDIOC_G_MPEGCOMP</constant> and -<constant>VIDIOC_S_MPEGCOMP</constant> ioctls, which were superseded -by the <link linkend="extended-controls">extended controls</link> -interface in Linux 2.6.18, where finally removed from the -<filename>videodev2.h</filename> header file.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.26</title> - <orderedlist> - <listitem> - <para>The pixel formats -<constant>V4L2_PIX_FMT_Y16</constant> and -<constant>V4L2_PIX_FMT_SBGGR16</constant> were added.</para> - </listitem> - <listitem> - <para>Added user controls -<constant>V4L2_CID_CHROMA_AGC</constant> and -<constant>V4L2_CID_COLOR_KILLER</constant>.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.27</title> - <orderedlist> - <listitem> - <para>The &VIDIOC-S-HW-FREQ-SEEK; ioctl and the -<constant>V4L2_CAP_HW_FREQ_SEEK</constant> capability were added.</para> - </listitem> - <listitem> - <para>The pixel formats -<constant>V4L2_PIX_FMT_YVYU</constant>, -<constant>V4L2_PIX_FMT_PCA501</constant>, -<constant>V4L2_PIX_FMT_PCA505</constant>, -<constant>V4L2_PIX_FMT_PCA508</constant>, -<constant>V4L2_PIX_FMT_PCA561</constant>, -<constant>V4L2_PIX_FMT_SGBRG8</constant>, -<constant>V4L2_PIX_FMT_PAC207</constant> and -<constant>V4L2_PIX_FMT_PJPG</constant> were added.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.28</title> - <orderedlist> - <listitem> - <para>Added <constant>V4L2_MPEG_AUDIO_ENCODING_AAC</constant> and -<constant>V4L2_MPEG_AUDIO_ENCODING_AC3</constant> MPEG audio encodings.</para> - </listitem> - <listitem> - <para>Added <constant>V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC</constant> MPEG -video encoding.</para> - </listitem> - <listitem> - <para>The pixel formats -<constant>V4L2_PIX_FMT_SGRBG10</constant> and -<constant>V4L2_PIX_FMT_SGRBG10DPCM8</constant> were added.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 2.6.29</title> - <orderedlist> - <listitem> - <para>The <constant>VIDIOC_G_CHIP_IDENT</constant> ioctl was renamed -to <constant>VIDIOC_G_CHIP_IDENT_OLD</constant> and <constant>VIDIOC_DBG_G_CHIP_IDENT</constant> -was introduced in its place. The old struct <structname>v4l2_chip_ident</structname> -was renamed to <structname id="v4l2-chip-ident-old">v4l2_chip_ident_old</structname>.</para> - </listitem> - <listitem> - <para>The pixel formats -<constant>V4L2_PIX_FMT_VYUY</constant>, -<constant>V4L2_PIX_FMT_NV16</constant> and -<constant>V4L2_PIX_FMT_NV61</constant> were added.</para> - </listitem> - <listitem> - <para>Added camera controls -<constant>V4L2_CID_ZOOM_ABSOLUTE</constant>, -<constant>V4L2_CID_ZOOM_RELATIVE</constant>, -<constant>V4L2_CID_ZOOM_CONTINUOUS</constant> and -<constant>V4L2_CID_PRIVACY</constant>.</para> - </listitem> - </orderedlist> - </section> - <section> - <title>V4L2 in Linux 2.6.30</title> - <orderedlist> - <listitem> - <para>New control flag <constant>V4L2_CTRL_FLAG_WRITE_ONLY</constant> was added.</para> - </listitem> - <listitem> - <para>New control <constant>V4L2_CID_COLORFX</constant> was added.</para> - </listitem> - </orderedlist> - </section> - <section> - <title>V4L2 in Linux 2.6.32</title> - <orderedlist> - <listitem> - <para>In order to be easier to compare a V4L2 API and a kernel -version, now V4L2 API is numbered using the Linux Kernel version numeration.</para> - </listitem> - <listitem> - <para>Finalized the RDS capture API. See <xref linkend="rds" /> for -more information.</para> - </listitem> - <listitem> - <para>Added new capabilities for modulators and RDS encoders.</para> - </listitem> - <listitem> - <para>Add description for libv4l API.</para> - </listitem> - <listitem> - <para>Added support for string controls via new type <constant>V4L2_CTRL_TYPE_STRING</constant>.</para> - </listitem> - <listitem> - <para>Added <constant>V4L2_CID_BAND_STOP_FILTER</constant> documentation.</para> - </listitem> - <listitem> - <para>Added FM Modulator (FM TX) Extended Control Class: <constant>V4L2_CTRL_CLASS_FM_TX</constant> and their Control IDs.</para> - </listitem> -<listitem> - <para>Added FM Receiver (FM RX) Extended Control Class: <constant>V4L2_CTRL_CLASS_FM_RX</constant> and their Control IDs.</para> - </listitem> - <listitem> - <para>Added Remote Controller chapter, describing the default Remote Controller mapping for media devices.</para> - </listitem> - </orderedlist> - </section> - <section> - <title>V4L2 in Linux 2.6.33</title> - <orderedlist> - <listitem> - <para>Added support for Digital Video timings in order to support HDTV receivers and transmitters.</para> - </listitem> - </orderedlist> - </section> - <section> - <title>V4L2 in Linux 2.6.34</title> - <orderedlist> - <listitem> - <para>Added -<constant>V4L2_CID_IRIS_ABSOLUTE</constant> and -<constant>V4L2_CID_IRIS_RELATIVE</constant> controls to the - <link linkend="camera-controls">Camera controls class</link>. - </para> - </listitem> - </orderedlist> - </section> - <section> - <title>V4L2 in Linux 2.6.37</title> - <orderedlist> - <listitem> - <para>Remove the vtx (videotext/teletext) API. This API was no longer -used and no hardware exists to verify the API. Nor were any userspace applications found -that used it. It was originally scheduled for removal in 2.6.35. - </para> - </listitem> - </orderedlist> - </section> - <section> - <title>V4L2 in Linux 2.6.39</title> - <orderedlist> - <listitem> - <para>The old VIDIOC_*_OLD symbols and V4L1 support were removed.</para> - </listitem> - <listitem> - <para>Multi-planar API added. Does not affect the compatibility of - current drivers and applications. See - <link linkend="planar-apis">multi-planar API</link> - for details.</para> - </listitem> - </orderedlist> - </section> - <section> - <title>V4L2 in Linux 3.1</title> - <orderedlist> - <listitem> - <para>VIDIOC_QUERYCAP now returns a per-subsystem version instead of a per-driver one.</para> - <para>Standardize an error code for invalid ioctl.</para> - <para>Added V4L2_CTRL_TYPE_BITMASK.</para> - </listitem> - </orderedlist> - </section> - <section> - <title>V4L2 in Linux 3.2</title> - <orderedlist> - <listitem> - <para>V4L2_CTRL_FLAG_VOLATILE was added to signal volatile controls to userspace.</para> - </listitem> - <listitem> - <para>Add selection API for extended control over cropping - and composing. Does not affect the compatibility of current - drivers and applications. See <link - linkend="selection-api"> selection API </link> for - details.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.3</title> - <orderedlist> - <listitem> - <para>Added <constant>V4L2_CID_ALPHA_COMPONENT</constant> control - to the <link linkend="control">User controls class</link>. - </para> - </listitem> - <listitem> - <para>Added the device_caps field to struct v4l2_capabilities and added the new - V4L2_CAP_DEVICE_CAPS capability.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.4</title> - <orderedlist> - <listitem> - <para>Added <link linkend="jpeg-controls">JPEG compression control - class</link>.</para> - </listitem> - <listitem> - <para>Extended the DV Timings API: - &VIDIOC-ENUM-DV-TIMINGS;, &VIDIOC-QUERY-DV-TIMINGS; and - &VIDIOC-DV-TIMINGS-CAP;.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.5</title> - <orderedlist> - <listitem> - <para>Added integer menus, the new type will be - V4L2_CTRL_TYPE_INTEGER_MENU.</para> - </listitem> - <listitem> - <para>Added selection API for V4L2 subdev interface: - &VIDIOC-SUBDEV-G-SELECTION; and - &VIDIOC-SUBDEV-S-SELECTION;.</para> - </listitem> - <listitem> - <para> Added <constant>V4L2_COLORFX_ANTIQUE</constant>, - <constant>V4L2_COLORFX_ART_FREEZE</constant>, - <constant>V4L2_COLORFX_AQUA</constant>, - <constant>V4L2_COLORFX_SILHOUETTE</constant>, - <constant>V4L2_COLORFX_SOLARIZATION</constant>, - <constant>V4L2_COLORFX_VIVID</constant> and - <constant>V4L2_COLORFX_ARBITRARY_CBCR</constant> menu items - to the <constant>V4L2_CID_COLORFX</constant> control.</para> - </listitem> - <listitem> - <para> Added <constant>V4L2_CID_COLORFX_CBCR</constant> control.</para> - </listitem> - <listitem> - <para> Added camera controls <constant>V4L2_CID_AUTO_EXPOSURE_BIAS</constant>, - <constant>V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE</constant>, - <constant>V4L2_CID_IMAGE_STABILIZATION</constant>, - <constant>V4L2_CID_ISO_SENSITIVITY</constant>, - <constant>V4L2_CID_ISO_SENSITIVITY_AUTO</constant>, - <constant>V4L2_CID_EXPOSURE_METERING</constant>, - <constant>V4L2_CID_SCENE_MODE</constant>, - <constant>V4L2_CID_3A_LOCK</constant>, - <constant>V4L2_CID_AUTO_FOCUS_START</constant>, - <constant>V4L2_CID_AUTO_FOCUS_STOP</constant>, - <constant>V4L2_CID_AUTO_FOCUS_STATUS</constant> and - <constant>V4L2_CID_AUTO_FOCUS_RANGE</constant>. - </para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.6</title> - <orderedlist> - <listitem> - <para>Replaced <structfield>input</structfield> in - <structname>v4l2_buffer</structname> by - <structfield>reserved2</structfield> and removed - <constant>V4L2_BUF_FLAG_INPUT</constant>.</para> - </listitem> - <listitem> - <para>Added V4L2_CAP_VIDEO_M2M and V4L2_CAP_VIDEO_M2M_MPLANE capabilities.</para> - </listitem> - <listitem> - <para>Added support for frequency band enumerations: &VIDIOC-ENUM-FREQ-BANDS;.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.9</title> - <orderedlist> - <listitem> - <para>Added timestamp types to - <structfield>flags</structfield> field in - <structname>v4l2_buffer</structname>. See <xref - linkend="buffer-flags" />.</para> - </listitem> - <listitem> - <para>Added <constant>V4L2_EVENT_CTRL_CH_RANGE</constant> control event - changes flag. See <xref linkend="ctrl-changes-flags"/>.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.10</title> - <orderedlist> - <listitem> - <para>Removed obsolete and unused DV_PRESET ioctls - VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET, VIDIOC_QUERY_DV_PRESET and - VIDIOC_ENUM_DV_PRESET. Remove the related v4l2_input/output capability - flags V4L2_IN_CAP_PRESETS and V4L2_OUT_CAP_PRESETS. - </para> - </listitem> - <listitem> - <para>Added new debugging ioctl &VIDIOC-DBG-G-CHIP-INFO;. - </para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.11</title> - <orderedlist> - <listitem> - <para>Remove obsolete <constant>VIDIOC_DBG_G_CHIP_IDENT</constant> ioctl. - </para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.14</title> - <orderedlist> - <listitem> - <para> In struct <structname>v4l2_rect</structname>, the type -of <structfield>width</structfield> and <structfield>height</structfield> -fields changed from _s32 to _u32. - </para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.15</title> - <orderedlist> - <listitem> - <para>Added Software Defined Radio (SDR) Interface. - </para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.16</title> - <orderedlist> - <listitem> - <para>Added event V4L2_EVENT_SOURCE_CHANGE. - </para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.17</title> - <orderedlist> - <listitem> - <para>Extended &v4l2-pix-format;. Added format flags. - </para> - </listitem> - <listitem> - <para>Added compound control types and &VIDIOC-QUERY-EXT-CTRL;. - </para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.18</title> - <orderedlist> - <listitem> - <para>Added <constant>V4L2_CID_PAN_SPEED</constant> and - <constant>V4L2_CID_TILT_SPEED</constant> camera controls.</para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 3.19</title> - <orderedlist> - <listitem> - <para>Rewrote Colorspace chapter, added new &v4l2-ycbcr-encoding; -and &v4l2-quantization; fields to &v4l2-pix-format;, &v4l2-pix-format-mplane; -and &v4l2-mbus-framefmt;. - </para> - </listitem> - </orderedlist> - </section> - - <section> - <title>V4L2 in Linux 4.4</title> - <orderedlist> - <listitem> - <para>Renamed <constant>V4L2_TUNER_ADC</constant> to -<constant>V4L2_TUNER_SDR</constant>. The use of -<constant>V4L2_TUNER_ADC</constant> is deprecated now. - </para> - </listitem> - <listitem> - <para>Added <constant>V4L2_CID_RF_TUNER_RF_GAIN</constant> -RF Tuner control.</para> - </listitem> - <listitem> - <para>Added transmitter support for Software Defined Radio (SDR) -Interface.</para> - </listitem> - </orderedlist> - </section> - - <section id="other"> - <title>Relation of V4L2 to other Linux multimedia APIs</title> - - <section id="xvideo"> - <title>X Video Extension</title> - - <para>The X Video Extension (abbreviated XVideo or just Xv) is -an extension of the X Window system, implemented for example by the -XFree86 project. Its scope is similar to V4L2, an API to video capture -and output devices for X clients. Xv allows applications to display -live video in a window, send window contents to a TV output, and -capture or output still images in XPixmaps<footnote> - <para>This is not implemented in XFree86.</para> - </footnote>. With their implementation XFree86 makes the -extension available across many operating systems and -architectures.</para> - - <para>Because the driver is embedded into the X server Xv has a -number of advantages over the V4L2 <link linkend="overlay">video -overlay interface</link>. The driver can easily determine the overlay -target, &ie; visible graphics memory or off-screen buffers for a -destructive overlay. It can program the RAMDAC for a non-destructive -overlay, scaling or color-keying, or the clipping functions of the -video capture hardware, always in sync with drawing operations or -windows moving or changing their stacking order.</para> - - <para>To combine the advantages of Xv and V4L a special Xv -driver exists in XFree86 and XOrg, just programming any overlay capable -Video4Linux device it finds. To enable it -<filename>/etc/X11/XF86Config</filename> must contain these lines:</para> - <para><screen> -Section "Module" - Load "v4l" -EndSection</screen></para> - - <para>As of XFree86 4.2 this driver still supports only V4L -ioctls, however it should work just fine with all V4L2 devices through -the V4L2 backward-compatibility layer. Since V4L2 permits multiple -opens it is possible (if supported by the V4L2 driver) to capture -video while an X client requested video overlay. Restrictions of -simultaneous capturing and overlay are discussed in <xref - linkend="overlay" /> apply.</para> - - <para>Only marginally related to V4L2, XFree86 extended Xv to -support hardware YUV to RGB conversion and scaling for faster video -playback, and added an interface to MPEG-2 decoding hardware. This API -is useful to display images captured with V4L2 devices.</para> - </section> - - <section> - <title>Digital Video</title> - - <para>V4L2 does not support digital terrestrial, cable or -satellite broadcast. A separate project aiming at digital receivers -exists. You can find its homepage at <ulink -url="https://linuxtv.org">https://linuxtv.org</ulink>. The Linux DVB API -has no connection to the V4L2 API except that drivers for hybrid -hardware may support both.</para> - </section> - - <section> - <title>Audio Interfaces</title> - - <para>[to do - OSS/ALSA]</para> - </section> - </section> - - <section id="experimental"> - <title>Experimental API Elements</title> - - <para>The following V4L2 API elements are currently experimental -and may change in the future.</para> - - <itemizedlist> - <listitem> - <para>&VIDIOC-DBG-G-REGISTER; and &VIDIOC-DBG-S-REGISTER; -ioctls.</para> - </listitem> - <listitem> - <para>&VIDIOC-DBG-G-CHIP-INFO; ioctl.</para> - </listitem> - </itemizedlist> - </section> - - <section id="obsolete"> - <title>Obsolete API Elements</title> - - <para>The following V4L2 API elements were superseded by new -interfaces and should not be implemented in new drivers.</para> - - <itemizedlist> - <listitem> - <para><constant>VIDIOC_G_MPEGCOMP</constant> and -<constant>VIDIOC_S_MPEGCOMP</constant> ioctls. Use Extended Controls, -<xref linkend="extended-controls" />.</para> - </listitem> - <listitem> - <para>VIDIOC_G_DV_PRESET, VIDIOC_S_DV_PRESET, VIDIOC_ENUM_DV_PRESETS and - VIDIOC_QUERY_DV_PRESET ioctls. Use the DV Timings API (<xref linkend="dv-timings" />).</para> - </listitem> - <listitem> - <para><constant>VIDIOC_SUBDEV_G_CROP</constant> and - <constant>VIDIOC_SUBDEV_S_CROP</constant> ioctls. Use - <constant>VIDIOC_SUBDEV_G_SELECTION</constant> and - <constant>VIDIOC_SUBDEV_S_SELECTION</constant>, <xref - linkend="vidioc-subdev-g-selection" />.</para> - </listitem> - </itemizedlist> - </section> - </section> |