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diff --git a/Documentation/userspace-api/media/dvb/video_types.rst b/Documentation/userspace-api/media/dvb/video_types.rst new file mode 100644 index 000000000000..bdba1d48f647 --- /dev/null +++ b/Documentation/userspace-api/media/dvb/video_types.rst @@ -0,0 +1,255 @@ +.. Permission is granted to copy, distribute and/or modify this +.. document under the terms of the GNU Free Documentation License, +.. Version 1.1 or any later version published by the Free Software +.. Foundation, with no Invariant Sections, no Front-Cover Texts +.. and no Back-Cover Texts. A copy of the license is included at +.. Documentation/userspace-api/media/fdl-appendix.rst. +.. +.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections + +.. _video_types: + +**************** +Video Data Types +**************** + + +.. _video-format-t: + +video_format_t +============== + +The ``video_format_t`` data type defined by + + +.. code-block:: c + + typedef enum { + VIDEO_FORMAT_4_3, /* Select 4:3 format */ + VIDEO_FORMAT_16_9, /* Select 16:9 format. */ + VIDEO_FORMAT_221_1 /* 2.21:1 */ + } video_format_t; + +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: + +video_displayformat_t +===================== + +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 + + +.. code-block:: c + + typedef enum { + VIDEO_PAN_SCAN, /* use pan and scan format */ + VIDEO_LETTER_BOX, /* use letterbox format */ + VIDEO_CENTER_CUT_OUT /* use center cut out format */ + } video_displayformat_t; + +as argument. + + +.. _video-stream-source-t: + +video_stream_source_t +===================== + +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. + + +.. code-block:: c + + typedef enum { + VIDEO_SOURCE_DEMUX, /* 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 */ + } video_stream_source_t; + +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: + +video_play_state_t +================== + +The following values can be returned by the VIDEO_GET_STATUS call +representing the state of video playback. + + +.. code-block:: c + + typedef enum { + VIDEO_STOPPED, /* Video is stopped */ + VIDEO_PLAYING, /* Video is currently playing */ + VIDEO_FREEZED /* Video is freezed */ + } video_play_state_t; + + +.. c:type:: video_command + +struct video_command +==================== + +The structure must be zeroed before use by the application This ensures +it can be extended safely in the future. + + +.. code-block:: c + + struct video_command { + __u32 cmd; + __u32 flags; + union { + struct { + __u64 pts; + } stop; + + struct { + /* 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. */ + __s32 speed; + __u32 format; + } play; + + struct { + __u32 data[16]; + } raw; + }; + }; + + +.. _video-size-t: + +video_size_t +============ + + +.. code-block:: c + + typedef struct { + int w; + int h; + video_format_t aspect_ratio; + } video_size_t; + + +.. c:type:: video_event + +struct video_event +================== + +The following is the structure of a video event as it is returned by the +VIDEO_GET_EVENT call. + + +.. 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; /* in frames per 1000sec */ + unsigned char vsync_field; /* unknown/odd/even/progressive */ + } u; + }; + + +.. c:type:: video_status + +struct video_status +=================== + +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; /* blank video on freeze? */ + 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;/* selected cropping mode */ + }; + +If video_blank is set 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 selected cropping mode in +case the source video format is not the same as the format of the output +device. + + +.. c:type:: video_still_picture + +struct video_still_picture +========================== + +An I-frame displayed via the VIDEO_STILLPICTURE call is passed on +within the following structure. + + +.. code-block:: c + + /* pointer to and size of a single iframe in memory */ + struct video_still_picture { + char *iFrame; /* pointer to a single iframe in memory */ + int32_t size; + }; + + +.. _video_caps: + +video capabilities +================== + +A call to VIDEO_GET_CAPABILITIES returns an unsigned integer with the +following bits set according to the hardwares capabilities. + + +.. code-block:: c + + /* bit definitions for capabilities: */ + /* can the hardware decode MPEG1 and/or MPEG2? */ + #define VIDEO_CAP_MPEG1 1 + #define VIDEO_CAP_MPEG2 2 + /* can you send a system and/or program stream to video device? + (you still have to open the video and the audio device but only + send the stream to the video device) */ + #define VIDEO_CAP_SYS 4 + #define VIDEO_CAP_PROG 8 + /* can the driver also handle SPU, NAVI and CSS encoded data? + (CSS API is not present yet) */ + #define VIDEO_CAP_SPU 16 + #define VIDEO_CAP_NAVI 32 + #define VIDEO_CAP_CSS 64 |