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diff --git a/Documentation/userspace-api/media/dvb/legacy_dvb_video.rst b/Documentation/userspace-api/media/dvb/legacy_dvb_video.rst new file mode 100644 index 000000000000..40e002f507a9 --- /dev/null +++ b/Documentation/userspace-api/media/dvb/legacy_dvb_video.rst @@ -0,0 +1,798 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later OR GPL-2.0 + +.. c:namespace:: dtv.legacy.video + +.. _dvb_video: + +================ +DVB Video Device +================ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +The DVB video device controls the MPEG2 video decoder of the DVB +hardware. It can be accessed through ``/dev/dvb/adapter0/video0``. Data +types and ioctl definitions can be accessed by including +``linux/dvb/video.h`` in your application. + +Note that the DVB video device only controls decoding of the MPEG video +stream, not its presentation on the TV or computer screen. On PCs this +is typically handled by an associated video4linux device, e.g. +``/dev/video``, which allows scaling and defining output windows. + +Most DVB cards don’t have their own MPEG decoder, which results in the +omission of the audio and video device as well as the video4linux +device. + +These ioctls were also used by V4L2 to control MPEG decoders implemented +in V4L2. The use of these ioctls for that purpose has been made obsolete +and proper V4L2 ioctls or controls have been created to replace that +functionality. Use :ref:`V4L2 ioctls<video>` for new drivers! + + +Video Data Types +================ + + + +video_format_t +-------------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + typedef enum { + VIDEO_FORMAT_4_3, + VIDEO_FORMAT_16_9, + VIDEO_FORMAT_221_1 + } video_format_t; + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``VIDEO_FORMAT_4_3`` + + - Select 4:3 format. + + - .. + + - ``VIDEO_FORMAT_16_9`` + + - Select 16:9 format. + + - .. + + - ``VIDEO_FORMAT_221_1`` + + - Select 2.21:1 format. + +Description +~~~~~~~~~~~ + +The ``video_format_t`` data type +is used in the `VIDEO_SET_FORMAT`_ function to tell the driver which +aspect ratio the output hardware (e.g. TV) has. It is also used in the +data structures `video_status`_ returned by `VIDEO_GET_STATUS`_ +and `video_event`_ returned by `VIDEO_GET_EVENT`_ which report +about the display format of the current video stream. + + +----- + + +video_displayformat_t +--------------------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + typedef enum { + VIDEO_PAN_SCAN, + VIDEO_LETTER_BOX, + VIDEO_CENTER_CUT_OUT + } video_displayformat_t; + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``VIDEO_PAN_SCAN`` + + - Use pan and scan format. + + - .. + + - ``VIDEO_LETTER_BOX`` + + - Use letterbox format. + + - .. + + - ``VIDEO_CENTER_CUT_OUT`` + + - Use center cut out format. + +Description +~~~~~~~~~~~ + +In case the display format of the video stream and of the display +hardware differ the application has to specify how to handle the +cropping of the picture. This can be done using the +`VIDEO_SET_DISPLAY_FORMAT`_ call which accepts this enum as argument. + + +----- + + +video_size_t +------------ + +Synopsis +~~~~~~~~ + +.. code-block:: c + + typedef struct { + int w; + int h; + video_format_t aspect_ratio; + } video_size_t; + +Variables +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int w`` + + - Video width in pixels. + + - .. + + - ``int h`` + + - Video height in pixels. + + - .. + + - `video_format_t`_ ``aspect_ratio`` + + - Aspect ratio. + +Description +~~~~~~~~~~~ + +Used in the struct `video_event`_. It stores the resolution and +aspect ratio of the video. + + +----- + + +video_stream_source_t +--------------------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + typedef enum { + VIDEO_SOURCE_DEMUX, + VIDEO_SOURCE_MEMORY + } video_stream_source_t; + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``VIDEO_SOURCE_DEMUX`` + + - :cspan:`1` Select the demux as the main source. + + - .. + + - ``VIDEO_SOURCE_MEMORY`` + + - If this source is selected, the stream + comes from the user through the write + system call. + +Description +~~~~~~~~~~~ + +The video stream source is set through the `VIDEO_SELECT_SOURCE`_ call +and can take the following values, depending on whether we are replaying +from an internal (demuxer) or external (user write) source. +VIDEO_SOURCE_DEMUX selects the demultiplexer (fed either by the +frontend or the DVR device) as the source of the video stream. If +VIDEO_SOURCE_MEMORY is selected the stream comes from the application +through the `write()`_ system call. + + +----- + + +video_play_state_t +------------------ + +Synopsis +~~~~~~~~ + +.. code-block:: c + + typedef enum { + VIDEO_STOPPED, + VIDEO_PLAYING, + VIDEO_FREEZED + } video_play_state_t; + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``VIDEO_STOPPED`` + + - Video is stopped. + + - .. + + - ``VIDEO_PLAYING`` + + - Video is currently playing. + + - .. + + - ``VIDEO_FREEZED`` + + - Video is frozen. + +Description +~~~~~~~~~~~ + +This values can be returned by the `VIDEO_GET_STATUS`_ call +representing the state of video playback. + + +----- + + +struct video_command +-------------------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + struct video_command { + __u32 cmd; + __u32 flags; + union { + struct { + __u64 pts; + } stop; + + struct { + __s32 speed; + __u32 format; + } play; + + struct { + __u32 data[16]; + } raw; + }; + }; + + +Variables +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``__u32 cmd`` + + - `Decoder command`_ + + - .. + + - ``__u32 flags`` + + - Flags for the `Decoder command`_. + + - .. + + - ``struct stop`` + + - ``__u64 pts`` + + - MPEG PTS + + - .. + + - :rspan:`5` ``stuct play`` + + - :rspan:`4` ``__s32 speed`` + + - 0 or 1000 specifies normal speed, + + - .. + + - 1: specifies forward single stepping, + + - .. + + - -1: specifies backward single stepping, + + - .. + + - >1: playback at speed / 1000 of the normal speed + + - .. + + - <-1: reverse playback at ( -speed / 1000 ) of the normal speed. + + - .. + + - ``__u32 format`` + + - `Play input formats`_ + + - .. + + - ``__u32 data[16]`` + + - Reserved + +Description +~~~~~~~~~~~ + +The structure must be zeroed before use by the application. This ensures +it can be extended safely in the future. + + +----- + + +Predefined decoder commands and flags +------------------------------------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + #define VIDEO_CMD_PLAY (0) + #define VIDEO_CMD_STOP (1) + #define VIDEO_CMD_FREEZE (2) + #define VIDEO_CMD_CONTINUE (3) + + #define VIDEO_CMD_FREEZE_TO_BLACK (1 << 0) + + #define VIDEO_CMD_STOP_TO_BLACK (1 << 0) + #define VIDEO_CMD_STOP_IMMEDIATELY (1 << 1) + + #define VIDEO_PLAY_FMT_NONE (0) + #define VIDEO_PLAY_FMT_GOP (1) + + #define VIDEO_VSYNC_FIELD_UNKNOWN (0) + #define VIDEO_VSYNC_FIELD_ODD (1) + #define VIDEO_VSYNC_FIELD_EVEN (2) + #define VIDEO_VSYNC_FIELD_PROGRESSIVE (3) + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - :rspan:`3` _`Decoder command` + + - ``VIDEO_CMD_PLAY`` + + - Start playback. + + - .. + + - ``VIDEO_CMD_STOP`` + + - Stop playback. + + - .. + + - ``VIDEO_CMD_FREEZE`` + + - Freeze playback. + + - .. + + - ``VIDEO_CMD_CONTINUE`` + + - Continue playback after freeze. + + - .. + + - Flags for ``VIDEO_CMD_FREEZE`` + + - ``VIDEO_CMD_FREEZE_TO_BLACK`` + + - Show black picture on freeze. + + - .. + + - :rspan:`1` Flags for ``VIDEO_CMD_STOP`` + + - ``VIDEO_CMD_STOP_TO_BLACK`` + + - Show black picture on stop. + + - .. + + - ``VIDEO_CMD_STOP_IMMEDIATELY`` + + - Stop immediately, without emptying buffers. + + - .. + + - :rspan:`1` _`Play input formats` + + - ``VIDEO_PLAY_FMT_NONE`` + + - The decoder has no special format requirements + + - .. + + - ``VIDEO_PLAY_FMT_GOP`` + + - The decoder requires full GOPs + + - .. + + - :rspan:`3` Field order + + - ``VIDEO_VSYNC_FIELD_UNKNOWN`` + + - FIELD_UNKNOWN can be used if the hardware does not know + whether the Vsync is for an odd, even or progressive + (i.e. non-interlaced) field. + + - .. + + - ``VIDEO_VSYNC_FIELD_ODD`` + + - Vsync is for an odd field. + + - .. + + - ``VIDEO_VSYNC_FIELD_EVEN`` + + - Vsync is for an even field. + + - .. + + - ``VIDEO_VSYNC_FIELD_PROGRESSIVE`` + + - progressive (i.e. non-interlaced) + + +----- + + +video_event +----------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + struct video_event { + __s32 type; + #define VIDEO_EVENT_SIZE_CHANGED 1 + #define VIDEO_EVENT_FRAME_RATE_CHANGED 2 + #define VIDEO_EVENT_DECODER_STOPPED 3 + #define VIDEO_EVENT_VSYNC 4 + long timestamp; + union { + video_size_t size; + unsigned int frame_rate; + unsigned char vsync_field; + } u; + }; + +Variables +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - :rspan:`4` ``__s32 type`` + + - :cspan:`1` Event type. + + - .. + + - ``VIDEO_EVENT_SIZE_CHANGED`` + + - Size changed. + + - .. + + - ``VIDEO_EVENT_FRAME_RATE_CHANGED`` + + - Framerate changed. + + - .. + + - ``VIDEO_EVENT_DECODER_STOPPED`` + + - Decoder stopped. + + - .. + + - ``VIDEO_EVENT_VSYNC`` + + - Vsync occurred. + + - .. + + - ``long timestamp`` + + - :cspan:`1` MPEG PTS at occurrence. + + - .. + + - :rspan:`2` ``union u`` + + - `video_size_t`_ size + + - Resolution and aspect ratio of the video. + + - .. + + - ``unsigned int frame_rate`` + + - in frames per 1000sec + + - .. + + - ``unsigned char vsync_field`` + + - | unknown / odd / even / progressive + | See: `Predefined decoder commands and flags`_ + +Description +~~~~~~~~~~~ + +This is the structure of a video event as it is returned by the +`VIDEO_GET_EVENT`_ call. See there for more details. + + +----- + + +video_status +------------ + +Synopsis +~~~~~~~~ + +The `VIDEO_GET_STATUS`_ call returns the following structure informing +about various states of the playback operation. + +.. code-block:: c + + struct video_status { + int video_blank; + video_play_state_t play_state; + video_stream_source_t stream_source; + video_format_t video_format; + video_displayformat_t display_format; + }; + +Variables +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - :rspan:`2` ``int video_blank`` + + - :cspan:`1` Show blank video on freeze? + + - .. + + - TRUE ( != 0 ) + + - Blank screen when freeze. + + - .. + + - FALSE ( == 0 ) + + - Show last decoded frame. + + - .. + + - `video_play_state_t`_ ``play_state`` + + - Current state of playback. + + - .. + + - `video_stream_source_t`_ ``stream_source`` + + - Current source (demux/memory). + + - .. + + - `video_format_t`_ ``video_format`` + + - Current aspect ratio of stream. + + - .. + + - `video_displayformat_t`_ ``display_format`` + + - Applied cropping mode. + +Description +~~~~~~~~~~~ + +If ``video_blank`` is set ``TRUE`` video will be blanked out if the +channel is changed or if playback is stopped. Otherwise, the last picture +will be displayed. ``play_state`` indicates if the video is currently +frozen, stopped, or being played back. The ``stream_source`` corresponds +to the selected source for the video stream. It can come either from the +demultiplexer or from memory. The ``video_format`` indicates the aspect +ratio (one of 4:3 or 16:9) of the currently played video stream. +Finally, ``display_format`` corresponds to the applied cropping mode in +case the source video format is not the same as the format of the output +device. + + +----- + + +video_still_picture +------------------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + struct video_still_picture { + char *iFrame; + int32_t size; + }; + +Variables +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``char *iFrame`` + + - Pointer to a single iframe in memory. + + - .. + + - ``int32_t size`` + + - Size of the iframe. + + +Description +~~~~~~~~~~~ + +An I-frame displayed via the `VIDEO_STILLPICTURE`_ call is passed on +within this structure. + + +----- + + +video capabilities +------------------ + +Synopsis +~~~~~~~~ + +.. code-block:: c + + #define VIDEO_CAP_MPEG1 1 + #define VIDEO_CAP_MPEG2 2 + #define VIDEO_CAP_SYS 4 + #define VIDEO_CAP_PROG 8 + +Constants +~~~~~~~~~ +Bit definitions for capabilities: + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``VIDEO_CAP_MPEG1`` + + - :cspan:`1` The hardware can decode MPEG1. + + - .. + + - ``VIDEO_CAP_MPEG2`` + + - The hardware can decode MPEG2. + + - .. + + - ``VIDEO_CAP_SYS`` + + - The video device accepts system stream. + + You still have to open the video and the audio device + but only send the stream to the video device. + + - .. + + - ``VIDEO_CAP_PROG`` + + - The video device accepts program stream. + + You still have to open the video and the audio device + but only send the stream to the video device. + +Description +~~~~~~~~~~~ + +A call to `VIDEO_GET_CAPABILITIES`_ returns an unsigned integer with the +following bits set according to the hardware's capabilities. |