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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
af4a4d0d | 3 | .. _VIDIOC_G_STD: |
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4 | |
5 | ******************************** | |
6 | ioctl VIDIOC_G_STD, VIDIOC_S_STD | |
7 | ******************************** | |
8 | ||
15e7d615 | 9 | Name |
586027ce | 10 | ==== |
5377d91f | 11 | |
586027ce | 12 | VIDIOC_G_STD - VIDIOC_S_STD - Query or select the video standard of the current input |
5377d91f | 13 | |
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14 | |
15 | Synopsis | |
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16 | ======== |
17 | ||
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18 | .. c:function:: int ioctl( int fd, VIDIOC_G_STD, v4l2_std_id *argp ) |
19 | :name: VIDIOC_G_STD | |
5377d91f | 20 | |
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21 | .. c:function:: int ioctl( int fd, VIDIOC_S_STD, const v4l2_std_id *argp ) |
22 | :name: VIDIOC_S_STD | |
5377d91f | 23 | |
586027ce | 24 | |
15e7d615 | 25 | Arguments |
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26 | ========= |
27 | ||
28 | ``fd`` | |
29 | File descriptor returned by :ref:`open() <func-open>`. | |
30 | ||
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31 | ``argp`` |
32 | ||
33 | ||
15e7d615 | 34 | Description |
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35 | =========== |
36 | ||
37 | To query and select the current video standard applications use the | |
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38 | :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a |
39 | :ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` | |
5377d91f | 40 | can return a single flag or a set of flags as in struct |
e8be7e97 | 41 | :c:type:`v4l2_standard` field ``id``. The flags must be |
5377d91f | 42 | unambiguous such that they appear in only one enumerated |
fc78c7c7 | 43 | struct :c:type:`v4l2_standard` structure. |
5377d91f | 44 | |
2212ff25 | 45 | :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it |
4e03cb76 | 46 | does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When |
5377d91f | 47 | no flags are given or the current input does not support the requested |
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48 | standard the driver returns an ``EINVAL`` error code. When the standard set |
49 | is ambiguous drivers may return ``EINVAL`` or choose any of the requested | |
5377d91f | 50 | standards. If the current input or output does not support standard |
7347081e | 51 | video timings (e.g. if :ref:`VIDIOC_ENUMINPUT` |
cdb4af0f | 52 | does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is |
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53 | returned. |
54 | ||
55 | ||
15e7d615 | 56 | Return Value |
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57 | ============ |
58 | ||
59 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
60 | appropriately. The generic error codes are described at the | |
61 | :ref:`Generic Error Codes <gen-errors>` chapter. | |
62 | ||
63 | EINVAL | |
2212ff25 | 64 | The :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable. |
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65 | |
66 | ENODATA | |
67 | Standard video timings are not supported for this input or output. |