| .. -*- coding: utf-8; mode: rst -*- |
| |
| .. _vidioc-g-sliced-vbi-cap: |
| |
| ***************************** |
| ioctl VIDIOC_G_SLICED_VBI_CAP |
| ***************************** |
| |
| *man VIDIOC_G_SLICED_VBI_CAP(2)* |
| |
| Query sliced VBI capabilities |
| |
| |
| Synopsis |
| ======== |
| |
| .. c:function:: int ioctl( int fd, int request, struct v4l2_sliced_vbi_cap *argp ) |
| |
| Arguments |
| ========= |
| |
| ``fd`` |
| File descriptor returned by :ref:`open() <func-open>`. |
| |
| ``request`` |
| VIDIOC_G_SLICED_VBI_CAP |
| |
| ``argp`` |
| |
| |
| 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 |
| :ref:`v4l2_sliced_vbi_cap <v4l2-sliced-vbi-cap>`, clear the |
| ``reserved`` array and call the ``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. |
| |
| |
| .. _v4l2-sliced-vbi-cap: |
| |
| .. flat-table:: struct v4l2_sliced_vbi_cap |
| :header-rows: 0 |
| :stub-columns: 0 |
| :widths: 3 3 2 2 2 |
| |
| |
| - .. row 1 |
| |
| - __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. |
| |
| - .. row 2 |
| |
| - __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 (see also :ref:`vbi-525` |
| and :ref:`vbi-625`) as follows: |
| |
| - .. row 3 |
| |
| - |
| - |
| - Element |
| |
| - 525 line systems |
| |
| - 625 line systems |
| |
| - .. row 4 |
| |
| - |
| - |
| - ``service_lines``\ [0][1] |
| |
| - 1 |
| |
| - 1 |
| |
| - .. row 5 |
| |
| - |
| - |
| - ``service_lines``\ [0][23] |
| |
| - 23 |
| |
| - 23 |
| |
| - .. row 6 |
| |
| - |
| - |
| - ``service_lines``\ [1][1] |
| |
| - 264 |
| |
| - 314 |
| |
| - .. row 7 |
| |
| - |
| - |
| - ``service_lines``\ [1][23] |
| |
| - 286 |
| |
| - 336 |
| |
| - .. row 8 |
| |
| - |
| |
| - .. row 9 |
| |
| - |
| - |
| - :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`. |
| |
| - .. row 10 |
| |
| - |
| |
| - .. row 11 |
| |
| - |
| - |
| - :cspan:`2` Drivers must set ``service_lines`` [0][0] and |
| ``service_lines``\ [1][0] to zero. |
| |
| - .. row 12 |
| |
| - __u32 |
| |
| - ``type`` |
| |
| - Type of the data stream, see :ref:`v4l2-buf-type`. Should be |
| ``V4L2_BUF_TYPE_SLICED_VBI_CAPTURE`` or |
| ``V4L2_BUF_TYPE_SLICED_VBI_OUTPUT``. |
| |
| - .. row 13 |
| |
| - __u32 |
| |
| - ``reserved``\ [3] |
| |
| - :cspan:`2` This array is reserved for future extensions. |
| Applications and drivers must set it to zero. |
| |
| |
| |
| .. _vbi-services: |
| |
| .. flat-table:: Sliced VBI services |
| :header-rows: 1 |
| :stub-columns: 0 |
| :widths: 2 1 1 2 2 |
| |
| |
| - .. row 1 |
| |
| - Symbol |
| |
| - Value |
| |
| - Reference |
| |
| - Lines, usually |
| |
| - Payload |
| |
| - .. row 2 |
| |
| - ``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. |
| |
| - .. row 3 |
| |
| - ``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. |
| |
| - .. row 4 |
| |
| - ``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. |
| |
| - .. row 5 |
| |
| - ``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 |
| |
| - .. row 6 |
| |
| - ``V4L2_SLICED_VBI_525`` |
| |
| - 0x1000 |
| |
| - :cspan:`2` Set of services applicable to 525 line systems. |
| |
| - .. row 7 |
| |
| - ``V4L2_SLICED_VBI_625`` |
| |
| - 0x4401 |
| |
| - :cspan:`2` Set of services applicable to 625 line systems. |
| |
| |
| |
| 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. |
| |
| |
| .. ------------------------------------------------------------------------------ |
| .. This file was automatically converted from DocBook-XML with the dbxml |
| .. library (https://github.com/return42/sphkerneldoc). The origin XML comes |
| .. from the linux kernel, refer to: |
| .. |
| .. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook |
| .. ------------------------------------------------------------------------------ |