| .. -*- coding: utf-8; mode: rst -*- |
| |
| .. _VIDIOC_ENUMSTD: |
| |
| ******************************************* |
| ioctl VIDIOC_ENUMSTD, VIDIOC_SUBDEV_ENUMSTD |
| ******************************************* |
| |
| Name |
| ==== |
| |
| VIDIOC_ENUMSTD - VIDIOC_SUBDEV_ENUMSTD - Enumerate supported video standards |
| |
| |
| Synopsis |
| ======== |
| |
| .. c:function:: int ioctl( int fd, VIDIOC_ENUMSTD, struct v4l2_standard *argp ) |
| :name: VIDIOC_ENUMSTD |
| |
| .. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_ENUMSTD, struct v4l2_standard *argp ) |
| :name: VIDIOC_SUBDEV_ENUMSTD |
| |
| |
| Arguments |
| ========= |
| |
| ``fd`` |
| File descriptor returned by :ref:`open() <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{8.7cm}| |
| |
| .. 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{8.7cm}| |
| |
| .. 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{8.7cm}| |
| |
| .. _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) |
