diff options
Diffstat (limited to 'Documentation/DocBook/media/v4l/pixfmt.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/pixfmt.xml | 61 |
1 files changed, 56 insertions, 5 deletions
diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml index 91dcbc84f3f8..df5b23d46552 100644 --- a/Documentation/DocBook/media/v4l/pixfmt.xml +++ b/Documentation/DocBook/media/v4l/pixfmt.xml @@ -112,9 +112,34 @@ see <xref linkend="colorspaces" />.</entry> <row> <entry>__u32</entry> <entry><structfield>priv</structfield></entry> - <entry>Reserved for custom (driver defined) additional -information about formats. When not used drivers and applications must -set this field to zero.</entry> + <entry><para>This field indicates whether the remaining fields of the +<structname>v4l2_pix_format</structname> structure, also called the extended +fields, are valid. When set to <constant>V4L2_PIX_FMT_PRIV_MAGIC</constant>, it +indicates that the extended fields have been correctly initialized. When set to +any other value it indicates that the extended fields contain undefined values. +</para> +<para>Applications that wish to use the pixel format extended fields must first +ensure that the feature is supported by querying the device for the +<link linkend="querycap"><constant>V4L2_CAP_EXT_PIX_FORMAT</constant></link> +capability. If the capability isn't set the pixel format extended fields are not +supported and using the extended fields will lead to undefined results.</para> +<para>To use the extended fields, applications must set the +<structfield>priv</structfield> field to +<constant>V4L2_PIX_FMT_PRIV_MAGIC</constant>, initialize all the extended fields +and zero the unused bytes of the <structname>v4l2_format</structname> +<structfield>raw_data</structfield> field.</para> +<para>When the <structfield>priv</structfield> field isn't set to +<constant>V4L2_PIX_FMT_PRIV_MAGIC</constant> drivers must act as if all the +extended fields were set to zero. On return drivers must set the +<structfield>priv</structfield> field to +<constant>V4L2_PIX_FMT_PRIV_MAGIC</constant> and all the extended fields to +applicable values.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Flags set by the application or driver, see <xref +linkend="format-flags" />.</entry> </row> </tbody> </tgroup> @@ -201,9 +226,15 @@ codes can be used.</entry> and the number of valid entries in the <structfield>plane_fmt</structfield> array.</entry> </row> + <row> + <entry>__u8</entry> + <entry><structfield>flags</structfield></entry> + <entry>Flags set by the application or driver, see <xref +linkend="format-flags" />.</entry> + </row> <row> <entry>__u8</entry> - <entry><structfield>reserved[11]</structfield></entry> + <entry><structfield>reserved[10]</structfield></entry> <entry>Reserved for future extensions. Should be zeroed by the application.</entry> </row> @@ -248,7 +279,7 @@ has just as many pad bytes after it as the other rows.</para> <para>In V4L2 each format has an identifier which looks like <constant>PIX_FMT_XXX</constant>, defined in the <link -linkend="videodev">videodev.h</link> header file. These identifiers +linkend="videodev">videodev2.h</link> header file. These identifiers represent <link linkend="v4l2-fourcc">four character (FourCC) codes</link> which are also listed below, however they are not the same as those used in the Windows world.</para> @@ -828,6 +859,9 @@ interface only.</para> &sub-sdr-cu08; &sub-sdr-cu16le; + &sub-sdr-cs08; + &sub-sdr-cs14le; + &sub-sdr-ru12le; </section> @@ -1060,4 +1094,21 @@ concatenated to form the JPEG stream. </para> </tbody> </tgroup> </table> + + <table frame="none" pgwide="1" id="format-flags"> + <title>Format Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_PIX_FMT_FLAG_PREMUL_ALPHA</constant></entry> + <entry>0x00000001</entry> + <entry>The color values are premultiplied by the alpha channel +value. For example, if a light blue pixel with 50% transparency was described by +RGBA values (128, 192, 255, 128), the same pixel described with premultiplied +colors would be described by RGBA values (64, 96, 128, 128) </entry> + </row> + </tbody> + </tgroup> + </table> </section> |