diff options
Diffstat (limited to 'Documentation/userspace-api/media/v4l/vidioc-g-sliced-vbi-cap.rst')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-g-sliced-vbi-cap.rst | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-sliced-vbi-cap.rst b/Documentation/userspace-api/media/v4l/vidioc-g-sliced-vbi-cap.rst new file mode 100644 index 000000000000..7a62c4f4e37f --- /dev/null +++ b/Documentation/userspace-api/media/v4l/vidioc-g-sliced-vbi-cap.rst @@ -0,0 +1,202 @@ +.. Permission is granted to copy, distribute and/or modify this +.. document under the terms of the GNU Free Documentation License, +.. Version 1.1 or any later version published by the Free Software +.. Foundation, with no Invariant Sections, no Front-Cover Texts +.. and no Back-Cover Texts. A copy of the license is included at +.. Documentation/userspace-api/media/fdl-appendix.rst. +.. +.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections + +.. _VIDIOC_G_SLICED_VBI_CAP: + +***************************** +ioctl VIDIOC_G_SLICED_VBI_CAP +***************************** + +Name +==== + +VIDIOC_G_SLICED_VBI_CAP - Query sliced VBI capabilities + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, VIDIOC_G_SLICED_VBI_CAP, struct v4l2_sliced_vbi_cap *argp ) + :name: VIDIOC_G_SLICED_VBI_CAP + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``argp`` + Pointer to struct :c:type:`v4l2_sliced_vbi_cap`. + + +Description +=========== + +To find out which data services are supported by a sliced VBI capture or +output device, applications initialize the ``type`` field of a struct +:c:type:`v4l2_sliced_vbi_cap`, clear the +``reserved`` array and call the :ref:`VIDIOC_G_SLICED_VBI_CAP <VIDIOC_G_SLICED_VBI_CAP>` ioctl. The +driver fills in the remaining fields or returns an ``EINVAL`` error code if +the sliced VBI API is unsupported or ``type`` is invalid. + +.. note:: + + The ``type`` field was added, and the ioctl changed from read-only + to write-read, in Linux 2.6.19. + + +.. c:type:: v4l2_sliced_vbi_cap + +.. tabularcolumns:: |p{1.2cm}|p{4.2cm}|p{4.1cm}|p{4.0cm}|p{4.0cm}| + +.. flat-table:: struct v4l2_sliced_vbi_cap + :header-rows: 0 + :stub-columns: 0 + :widths: 3 3 2 2 2 + + * - __u16 + - ``service_set`` + - :cspan:`2` A set of all data services supported by the driver. + + Equal to the union of all elements of the ``service_lines`` array. + * - __u16 + - ``service_lines``\ [2][24] + - :cspan:`2` Each element of this array contains a set of data + services the hardware can look for or insert into a particular + scan line. Data services are defined in :ref:`vbi-services`. + Array indices map to ITU-R line numbers\ [#f1]_ as follows: + * - + - + - Element + - 525 line systems + - 625 line systems + * - + - + - ``service_lines``\ [0][1] + - 1 + - 1 + * - + - + - ``service_lines``\ [0][23] + - 23 + - 23 + * - + - + - ``service_lines``\ [1][1] + - 264 + - 314 + * - + - + - ``service_lines``\ [1][23] + - 286 + - 336 + * - + * - + - + - :cspan:`2` The number of VBI lines the hardware can capture or + output per frame, or the number of services it can identify on a + given line may be limited. For example on PAL line 16 the hardware + may be able to look for a VPS or Teletext signal, but not both at + the same time. Applications can learn about these limits using the + :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl as described in + :ref:`sliced`. + * - + * - + - + - :cspan:`2` Drivers must set ``service_lines`` [0][0] and + ``service_lines``\ [1][0] to zero. + * - __u32 + - ``type`` + - Type of the data stream, see :c:type:`v4l2_buf_type`. Should be + ``V4L2_BUF_TYPE_SLICED_VBI_CAPTURE`` or + ``V4L2_BUF_TYPE_SLICED_VBI_OUTPUT``. + * - __u32 + - ``reserved``\ [3] + - :cspan:`2` This array is reserved for future extensions. + + Applications and drivers must set it to zero. + +.. [#f1] + + See also :ref:`vbi-525` and :ref:`vbi-625`. + + +.. raw:: latex + + \scriptsize + +.. tabularcolumns:: |p{3.5cm}|p{1.0cm}|p{2.0cm}|p{2.0cm}|p{8.0cm}| + +.. _vbi-services: + +.. flat-table:: Sliced VBI services + :header-rows: 1 + :stub-columns: 0 + :widths: 2 1 1 2 2 + + * - Symbol + - Value + - Reference + - Lines, usually + - Payload + * - ``V4L2_SLICED_TELETEXT_B`` (Teletext System B) + - 0x0001 + - :ref:`ets300706`, + + :ref:`itu653` + - PAL/SECAM line 7-22, 320-335 (second field 7-22) + - Last 42 of the 45 byte Teletext packet, that is without clock + run-in and framing code, lsb first transmitted. + * - ``V4L2_SLICED_VPS`` + - 0x0400 + - :ref:`ets300231` + - PAL line 16 + - Byte number 3 to 15 according to Figure 9 of ETS 300 231, lsb + first transmitted. + * - ``V4L2_SLICED_CAPTION_525`` + - 0x1000 + - :ref:`cea608` + - NTSC line 21, 284 (second field 21) + - Two bytes in transmission order, including parity bit, lsb first + transmitted. + * - ``V4L2_SLICED_WSS_625`` + - 0x4000 + - :ref:`en300294`, + + :ref:`itu1119` + - PAL/SECAM line 23 + - + + :: + + Byte 0 1 + msb lsb msb lsb + Bit 7 6 5 4 3 2 1 0 x x 13 12 11 10 9 + * - ``V4L2_SLICED_VBI_525`` + - 0x1000 + - :cspan:`2` Set of services applicable to 525 line systems. + * - ``V4L2_SLICED_VBI_625`` + - 0x4401 + - :cspan:`2` Set of services applicable to 625 line systems. + +.. raw:: latex + + \normalsize + + +Return Value +============ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + +EINVAL + The value in the ``type`` field is wrong. |