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diff --git a/Documentation/userspace-api/media/v4l/vidioc-enumstd.rst b/Documentation/userspace-api/media/v4l/vidioc-enumstd.rst new file mode 100644 index 000000000..6af71b74d --- /dev/null +++ b/Documentation/userspace-api/media/v4l/vidioc-enumstd.rst @@ -0,0 +1,351 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L + +.. _VIDIOC_ENUMSTD: + +******************************************* +ioctl VIDIOC_ENUMSTD, VIDIOC_SUBDEV_ENUMSTD +******************************************* + +Name +==== + +VIDIOC_ENUMSTD - VIDIOC_SUBDEV_ENUMSTD - Enumerate supported video standards + +Synopsis +======== + +.. c:macro:: VIDIOC_ENUMSTD + +``int ioctl(int fd, VIDIOC_ENUMSTD, struct v4l2_standard *argp)`` + +.. c:macro:: VIDIOC_SUBDEV_ENUMSTD + +``int ioctl(int fd, VIDIOC_SUBDEV_ENUMSTD, struct v4l2_standard *argp)`` + +Arguments +========= + +``fd`` + File descriptor returned by :c:func:`open()`. + +``argp`` + Pointer to struct :c:type:`v4l2_standard`. + +Description +=========== + +To query the attributes of a video standard, especially a custom (driver +defined) one, applications initialize the ``index`` field of struct +:c:type:`v4l2_standard` and call the :ref:`VIDIOC_ENUMSTD` +ioctl with a pointer to this structure. Drivers fill the rest of the +structure or return an ``EINVAL`` error code when the index is out of +bounds. To enumerate all standards applications shall begin at index +zero, incrementing by one until the driver returns ``EINVAL``. Drivers may +enumerate a different set of standards after switching the video input +or output. [#f1]_ + +.. c:type:: v4l2_standard + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| + +.. flat-table:: struct v4l2_standard + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``index`` + - Number of the video standard, set by the application. + * - :ref:`v4l2_std_id <v4l2-std-id>` + - ``id`` + - The bits in this field identify the standard as one of the common + standards listed in :ref:`v4l2-std-id`, or if bits 32 to 63 are + set as custom standards. Multiple bits can be set if the hardware + does not distinguish between these standards, however separate + indices do not indicate the opposite. The ``id`` must be unique. + No other enumerated struct :c:type:`v4l2_standard` structure, + for this input or output anyway, can contain the same set of bits. + * - __u8 + - ``name``\ [24] + - Name of the standard, a NUL-terminated ASCII string, for example: + "PAL-B/G", "NTSC Japan". This information is intended for the + user. + * - struct :c:type:`v4l2_fract` + - ``frameperiod`` + - The frame period (not field period) is numerator / denominator. + For example M/NTSC has a frame period of 1001 / 30000 seconds. + * - __u32 + - ``framelines`` + - Total lines per frame including blanking, e. g. 625 for B/PAL. + * - __u32 + - ``reserved``\ [4] + - Reserved for future extensions. Drivers must set the array to + zero. + + +.. c:type:: v4l2_fract + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| + +.. flat-table:: struct v4l2_fract + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``numerator`` + - + * - __u32 + - ``denominator`` + - + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| + +.. _v4l2-std-id: + +.. flat-table:: typedef v4l2_std_id + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u64 + - ``v4l2_std_id`` + - This type is a set, each bit representing another video standard + as listed below and in :ref:`video-standards`. The 32 most + significant bits are reserved for custom (driver defined) video + standards. + + +.. code-block:: c + + #define V4L2_STD_PAL_B ((v4l2_std_id)0x00000001) + #define V4L2_STD_PAL_B1 ((v4l2_std_id)0x00000002) + #define V4L2_STD_PAL_G ((v4l2_std_id)0x00000004) + #define V4L2_STD_PAL_H ((v4l2_std_id)0x00000008) + #define V4L2_STD_PAL_I ((v4l2_std_id)0x00000010) + #define V4L2_STD_PAL_D ((v4l2_std_id)0x00000020) + #define V4L2_STD_PAL_D1 ((v4l2_std_id)0x00000040) + #define V4L2_STD_PAL_K ((v4l2_std_id)0x00000080) + + #define V4L2_STD_PAL_M ((v4l2_std_id)0x00000100) + #define V4L2_STD_PAL_N ((v4l2_std_id)0x00000200) + #define V4L2_STD_PAL_Nc ((v4l2_std_id)0x00000400) + #define V4L2_STD_PAL_60 ((v4l2_std_id)0x00000800) + +``V4L2_STD_PAL_60`` is a hybrid standard with 525 lines, 60 Hz refresh +rate, and PAL color modulation with a 4.43 MHz color subcarrier. Some +PAL video recorders can play back NTSC tapes in this mode for display on +a 50/60 Hz agnostic PAL TV. + +.. code-block:: c + + #define V4L2_STD_NTSC_M ((v4l2_std_id)0x00001000) + #define V4L2_STD_NTSC_M_JP ((v4l2_std_id)0x00002000) + #define V4L2_STD_NTSC_443 ((v4l2_std_id)0x00004000) + +``V4L2_STD_NTSC_443`` is a hybrid standard with 525 lines, 60 Hz refresh +rate, and NTSC color modulation with a 4.43 MHz color subcarrier. + +.. code-block:: c + + #define V4L2_STD_NTSC_M_KR ((v4l2_std_id)0x00008000) + + #define V4L2_STD_SECAM_B ((v4l2_std_id)0x00010000) + #define V4L2_STD_SECAM_D ((v4l2_std_id)0x00020000) + #define V4L2_STD_SECAM_G ((v4l2_std_id)0x00040000) + #define V4L2_STD_SECAM_H ((v4l2_std_id)0x00080000) + #define V4L2_STD_SECAM_K ((v4l2_std_id)0x00100000) + #define V4L2_STD_SECAM_K1 ((v4l2_std_id)0x00200000) + #define V4L2_STD_SECAM_L ((v4l2_std_id)0x00400000) + #define V4L2_STD_SECAM_LC ((v4l2_std_id)0x00800000) + + /* ATSC/HDTV */ + #define V4L2_STD_ATSC_8_VSB ((v4l2_std_id)0x01000000) + #define V4L2_STD_ATSC_16_VSB ((v4l2_std_id)0x02000000) + +``V4L2_STD_ATSC_8_VSB`` and ``V4L2_STD_ATSC_16_VSB`` are U.S. +terrestrial digital TV standards. Presently the V4L2 API does not +support digital TV. See also the Linux DVB API at +`https://linuxtv.org <https://linuxtv.org>`__. + +.. code-block:: c + + #define V4L2_STD_PAL_BG (V4L2_STD_PAL_B | + V4L2_STD_PAL_B1 | + V4L2_STD_PAL_G) + #define V4L2_STD_B (V4L2_STD_PAL_B | + V4L2_STD_PAL_B1 | + V4L2_STD_SECAM_B) + #define V4L2_STD_GH (V4L2_STD_PAL_G | + V4L2_STD_PAL_H | + V4L2_STD_SECAM_G | + V4L2_STD_SECAM_H) + #define V4L2_STD_PAL_DK (V4L2_STD_PAL_D | + V4L2_STD_PAL_D1 | + V4L2_STD_PAL_K) + #define V4L2_STD_PAL (V4L2_STD_PAL_BG | + V4L2_STD_PAL_DK | + V4L2_STD_PAL_H | + V4L2_STD_PAL_I) + #define V4L2_STD_NTSC (V4L2_STD_NTSC_M | + V4L2_STD_NTSC_M_JP | + V4L2_STD_NTSC_M_KR) + #define V4L2_STD_MN (V4L2_STD_PAL_M | + V4L2_STD_PAL_N | + V4L2_STD_PAL_Nc | + V4L2_STD_NTSC) + #define V4L2_STD_SECAM_DK (V4L2_STD_SECAM_D | + V4L2_STD_SECAM_K | + V4L2_STD_SECAM_K1) + #define V4L2_STD_DK (V4L2_STD_PAL_DK | + V4L2_STD_SECAM_DK) + + #define V4L2_STD_SECAM (V4L2_STD_SECAM_B | + V4L2_STD_SECAM_G | + V4L2_STD_SECAM_H | + V4L2_STD_SECAM_DK | + V4L2_STD_SECAM_L | + V4L2_STD_SECAM_LC) + + #define V4L2_STD_525_60 (V4L2_STD_PAL_M | + V4L2_STD_PAL_60 | + V4L2_STD_NTSC | + V4L2_STD_NTSC_443) + #define V4L2_STD_625_50 (V4L2_STD_PAL | + V4L2_STD_PAL_N | + V4L2_STD_PAL_Nc | + V4L2_STD_SECAM) + + #define V4L2_STD_UNKNOWN 0 + #define V4L2_STD_ALL (V4L2_STD_525_60 | + V4L2_STD_625_50) + +.. raw:: latex + + \begingroup + \tiny + \setlength{\tabcolsep}{2pt} + +.. NTSC/M PAL/M /N /B /D /H /I SECAM/B /D /K1 /L +.. tabularcolumns:: |p{1.43cm}|p{1.38cm}|p{1.59cm}|p{1.7cm}|p{1.7cm}|p{1.17cm}|p{0.64cm}|p{1.71cm}|p{1.6cm}|p{1.07cm}|p{1.07cm}|p{1.07cm}| + +.. _video-standards: + +.. flat-table:: Video Standards (based on :ref:`itu470`) + :header-rows: 1 + :stub-columns: 0 + + * - Characteristics + - M/NTSC [#f2]_ + - M/PAL + - N/PAL [#f3]_ + - B, B1, G/PAL + - D, D1, K/PAL + - H/PAL + - I/PAL + - B, G/SECAM + - D, K/SECAM + - K1/SECAM + - L/SECAM + * - Frame lines + - :cspan:`1` 525 + - :cspan:`8` 625 + * - Frame period (s) + - :cspan:`1` 1001/30000 + - :cspan:`8` 1/25 + * - Chrominance sub-carrier frequency (Hz) + - 3579545 ± 10 + - 3579611.49 ± 10 + - 4433618.75 ± 5 + + (3582056.25 ± 5) + - :cspan:`3` 4433618.75 ± 5 + - 4433618.75 ± 1 + - :cspan:`2` f\ :sub:`OR` = 4406250 ± 2000, + + f\ :sub:`OB` = 4250000 ± 2000 + * - Nominal radio-frequency channel bandwidth (MHz) + - 6 + - 6 + - 6 + - B: 7; B1, G: 8 + - 8 + - 8 + - 8 + - 8 + - 8 + - 8 + - 8 + * - Sound carrier relative to vision carrier (MHz) + - 4.5 + - 4.5 + - 4.5 + - 5.5 ± 0.001 [#f4]_ [#f5]_ [#f6]_ [#f7]_ + - 6.5 ± 0.001 + - 5.5 + - 5.9996 ± 0.0005 + - 5.5 ± 0.001 + - 6.5 ± 0.001 + - 6.5 + - 6.5 [#f8]_ + +.. raw:: latex + + \endgroup + + +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 struct :c:type:`v4l2_standard` ``index`` is out + of bounds. + +ENODATA + Standard video timings are not supported for this input or output. + +.. [#f1] + The supported standards may overlap and we need an unambiguous set to + find the current standard returned by :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`. + +.. [#f2] + Japan uses a standard similar to M/NTSC (V4L2_STD_NTSC_M_JP). + +.. [#f3] + The values in brackets apply to the combination N/PAL a.k.a. + N\ :sub:`C` used in Argentina (V4L2_STD_PAL_Nc). + +.. [#f4] + In the Federal Republic of Germany, Austria, Italy, the Netherlands, + Slovakia and Switzerland a system of two sound carriers is used, the + frequency of the second carrier being 242.1875 kHz above the + frequency of the first sound carrier. For stereophonic sound + transmissions a similar system is used in Australia. + +.. [#f5] + New Zealand uses a sound carrier displaced 5.4996 ± 0.0005 MHz from + the vision carrier. + +.. [#f6] + In Denmark, Finland, New Zealand, Sweden and Spain a system of two + sound carriers is used. In Iceland, Norway and Poland the same system + is being introduced. The second carrier is 5.85 MHz above the vision + carrier and is DQPSK modulated with 728 kbit/s sound and data + multiplex. (NICAM system) + +.. [#f7] + In the United Kingdom, a system of two sound carriers is used. The + second sound carrier is 6.552 MHz above the vision carrier and is + DQPSK modulated with a 728 kbit/s sound and data multiplex able to + carry two sound channels. (NICAM system) + +.. [#f8] + In France, a digital carrier 5.85 MHz away from the vision carrier + may be used in addition to the main sound carrier. It is modulated in + differentially encoded QPSK with a 728 kbit/s sound and data + multiplexer capable of carrying two sound channels. (NICAM system) |