From 8e080c2e6cadada82a6b520e0c23a1cb974822d5 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Sun, 13 Sep 2009 22:16:04 -0300 Subject: V4L/DVB (12761): DocBook: add media API specs The V4L and DVB API's are there for a long time. however, up to now, no efforts were done to merge them to kernel DocBook. This patch adds the current versions of the specs as an unique compendium. Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/dvb/audio.xml | 1473 +++++++++++++++++++++++++++++++++++ 1 file changed, 1473 insertions(+) create mode 100644 Documentation/DocBook/dvb/audio.xml (limited to 'Documentation/DocBook/dvb/audio.xml') diff --git a/Documentation/DocBook/dvb/audio.xml b/Documentation/DocBook/dvb/audio.xml new file mode 100644 index 00000000000..eeb96b8a086 --- /dev/null +++ b/Documentation/DocBook/dvb/audio.xml @@ -0,0 +1,1473 @@ +DVB Audio Device +The DVB audio device controls the MPEG2 audio decoder of the DVB hardware. It +can be accessed through /dev/dvb/adapter0/audio0. Data types and and +ioctl definitions can be accessed by including linux/dvb/video.h in your +application. + +Please note that some DVB cards don’t have their own MPEG decoder, which results in +the omission of the audio and video device. + + +
+Audio Data Types +This section describes the structures, data types and defines used when talking to the +audio device. + + +
+audio_stream_source_t +The audio stream source is set through the AUDIO_SELECT_SOURCE call and can take +the following values, depending on whether we are replaying from an internal (demux) or +external (user write) source. + + + typedef enum { + AUDIO_SOURCE_DEMUX, + AUDIO_SOURCE_MEMORY + } audio_stream_source_t; + +AUDIO_SOURCE_DEMUX selects the demultiplexer (fed either by the frontend or the +DVR device) as the source of the video stream. If AUDIO_SOURCE_MEMORY +is selected the stream comes from the application through the write() system +call. + + +
+
+audio_play_state_t +The following values can be returned by the AUDIO_GET_STATUS call representing the +state of audio playback. + + + typedef enum { + AUDIO_STOPPED, + AUDIO_PLAYING, + AUDIO_PAUSED + } audio_play_state_t; + + +
+
+audio_channel_select_t +The audio channel selected via AUDIO_CHANNEL_SELECT is determined by the +following values. + + + typedef enum { + AUDIO_STEREO, + AUDIO_MONO_LEFT, + AUDIO_MONO_RIGHT, + } audio_channel_select_t; + + +
+
+struct audio_status +The AUDIO_GET_STATUS call returns the following structure informing about various +states of the playback operation. + + + typedef struct audio_status { + boolean AV_sync_state; + boolean mute_state; + audio_play_state_t play_state; + audio_stream_source_t stream_source; + audio_channel_select_t channel_select; + boolean bypass_mode; + } audio_status_t; + + +
+
+struct audio_mixer +The following structure is used by the AUDIO_SET_MIXER call to set the audio +volume. + + + typedef struct audio_mixer { + unsigned int volume_left; + unsigned int volume_right; + } audio_mixer_t; + + +
+
+audio encodings +A call to AUDIO_GET_CAPABILITIES returns an unsigned integer with the following +bits set according to the hardwares capabilities. + + + #define AUDIO_CAP_DTS 1 + #define AUDIO_CAP_LPCM 2 + #define AUDIO_CAP_MP1 4 + #define AUDIO_CAP_MP2 8 + #define AUDIO_CAP_MP3 16 + #define AUDIO_CAP_AAC 32 + #define AUDIO_CAP_OGG 64 + #define AUDIO_CAP_SDDS 128 + #define AUDIO_CAP_AC3 256 + + +
+
+struct audio_karaoke +The ioctl AUDIO_SET_KARAOKE uses the following format: + + + typedef + struct audio_karaoke{ + int vocal1; + int vocal2; + int melody; + } audio_karaoke_t; + +If Vocal1 or Vocal2 are non-zero, they get mixed into left and right t at 70% each. If both, +Vocal1 and Vocal2 are non-zero, Vocal1 gets mixed into the left channel and Vocal2 into the +right channel at 100% each. Ff Melody is non-zero, the melody channel gets mixed into left +and right. + + +
+
+audio attributes +The following attributes can be set by a call to AUDIO_SET_ATTRIBUTES: + + + typedef uint16_t audio_attributes_t; + /⋆ bits: descr. ⋆/ + /⋆ 15-13 audio coding mode (0=ac3, 2=mpeg1, 3=mpeg2ext, 4=LPCM, 6=DTS, ⋆/ + /⋆ 12 multichannel extension ⋆/ + /⋆ 11-10 audio type (0=not spec, 1=language included) ⋆/ + /⋆ 9- 8 audio application mode (0=not spec, 1=karaoke, 2=surround) ⋆/ + /⋆ 7- 6 Quantization / DRC (mpeg audio: 1=DRC exists)(lpcm: 0=16bit, ⋆/ + /⋆ 5- 4 Sample frequency fs (0=48kHz, 1=96kHz) ⋆/ + /⋆ 2- 0 number of audio channels (n+1 channels) ⋆/ + +
+
+Audio Function Calls + + +
+open() +DESCRIPTION + + +This system call opens a named audio device (e.g. /dev/dvb/adapter0/audio0) + for subsequent use. When an open() call has succeeded, the device will be ready + for use. The significance of blocking or non-blocking mode is described in the + documentation for functions where there is a difference. It does not affect the + semantics of the open() call itself. A device opened in blocking mode can later + be put into non-blocking mode (and vice versa) using the F_SETFL command + of the fcntl system call. This is a standard system call, documented in the Linux + manual page for fcntl. Only one user can open the Audio Device in O_RDWR + mode. All other attempts to open the device in this mode will fail, and an error + code will be returned. If the Audio Device is opened in O_RDONLY mode, the + only ioctl call that can be used is AUDIO_GET_STATUS. All other call will + return with an error code. + + +SYNOPSIS + + +int open(const char ⋆deviceName, int flags); + + +PARAMETERS + + +const char + *deviceName + +Name of specific audio device. + + +int flags + +A bit-wise OR of the following flags: + + + +O_RDONLY read-only access + + + +O_RDWR read/write access + + + +O_NONBLOCK open in non-blocking mode + + + +(blocking mode is the default) + + +ERRORS + + +ENODEV + +Device driver not loaded/available. + + +EINTERNAL + +Internal error. + + +EBUSY + +Device or resource busy. + + +EINVAL + +Invalid argument. + + + +
+
+close() +DESCRIPTION + + +This system call closes a previously opened audio device. + + +SYNOPSIS + + +int close(int fd); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + + +
+
+write() +DESCRIPTION + + +This system call can only be used if AUDIO_SOURCE_MEMORY is selected + in the ioctl call AUDIO_SELECT_SOURCE. The data provided shall be in + PES format. If O_NONBLOCK is not specified the function will block until + buffer space is available. The amount of data to be transferred is implied by + count. + + +SYNOPSIS + + +size_t write(int fd, const void ⋆buf, size_t count); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +void *buf + +Pointer to the buffer containing the PES data. + + +size_t count + +Size of buf. + + +ERRORS + + +EPERM + +Mode AUDIO_SOURCE_MEMORY not selected. + + +ENOMEM + +Attempted to write more data than the internal buffer can + hold. + + +EBADF + +fd is not a valid open file descriptor. + + + +
AUDIO_STOP +DESCRIPTION + + +This ioctl call asks the Audio Device to stop playing the current stream. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_STOP); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_STOP for this command. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor + + +EINTERNAL + +Internal error. + + + +
AUDIO_PLAY +DESCRIPTION + + +This ioctl call asks the Audio Device to start playing an audio stream from the + selected source. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_PLAY); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_PLAY for this command. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor + + +EINTERNAL + +Internal error. + + + +
AUDIO_PAUSE +DESCRIPTION + + +This ioctl call suspends the audio stream being played. Decoding and playing + are paused. It is then possible to restart again decoding and playing process of + the audio stream using AUDIO_CONTINUE command. + + +If AUDIO_SOURCE_MEMORY is selected in the ioctl call + AUDIO_SELECT_SOURCE, the DVB-subsystem will not decode (consume) + any more data until the ioctl call AUDIO_CONTINUE or AUDIO_PLAY is + performed. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_PAUSE); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_PAUSE for this command. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + + +
AUDIO_SELECT_SOURCE +DESCRIPTION + + +This ioctl call informs the audio device which source shall be used + for the input data. The possible sources are demux or memory. If + AUDIO_SOURCE_MEMORY is selected, the data is fed to the Audio Device + through the write command. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_SELECT_SOURCE, + audio_stream_source_t source); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SELECT_SOURCE for this command. + + +audio_stream_source_t + source + +Indicates the source that shall be used for the Audio + stream. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EINVAL + +Illegal input parameter. + + + +
AUDIO_SET_MUTE +DESCRIPTION + + +This ioctl call asks the audio device to mute the stream that is currently being + played. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_SET_MUTE, + boolean state); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SET_MUTE for this command. + + +boolean state + +Indicates if audio device shall mute or not. + + + +TRUE Audio Mute + + + +FALSE Audio Un-mute + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EINVAL + +Illegal input parameter. + + + +
AUDIO_SET_AV_SYNC +DESCRIPTION + + +This ioctl call asks the Audio Device to turn ON or OFF A/V synchronization. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_SET_AV_SYNC, + boolean state); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_AV_SYNC for this command. + + +boolean state + +Tells the DVB subsystem if A/V synchronization shall be + ON or OFF. + + + +TRUE AV-sync ON + + + +FALSE AV-sync OFF + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EINVAL + +Illegal input parameter. + + + +
AUDIO_SET_BYPASS_MODE +DESCRIPTION + + +This ioctl call asks the Audio Device to bypass the Audio decoder and forward + the stream without decoding. This mode shall be used if streams that can’t be + handled by the DVB system shall be decoded. Dolby DigitalTM streams are + automatically forwarded by the DVB subsystem if the hardware can handle it. + + +SYNOPSIS + + +int ioctl(int fd, int request = + AUDIO_SET_BYPASS_MODE, boolean mode); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SET_BYPASS_MODE for this + command. + + +boolean mode + +Enables or disables the decoding of the current Audio + stream in the DVB subsystem. + + + +TRUE Bypass is disabled + + + +FALSE Bypass is enabled + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EINVAL + +Illegal input parameter. + + + +
AUDIO_CHANNEL_SELECT +DESCRIPTION + + +This ioctl call asks the Audio Device to select the requested channel if possible. + + +SYNOPSIS + + +int ioctl(int fd, int request = + AUDIO_CHANNEL_SELECT, audio_channel_select_t); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_CHANNEL_SELECT for this + command. + + +audio_channel_select_t + ch + +Select the output format of the audio (mono left/right, + stereo). + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EINVAL + +Illegal input parameter ch. + + + +
AUDIO_GET_STATUS +DESCRIPTION + + +This ioctl call asks the Audio Device to return the current state of the Audio + Device. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_GET_STATUS, + struct audio_status ⋆status); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_GET_STATUS for this command. + + +struct audio_status + *status + +Returns the current state of Audio Device. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EFAULT + +status points to invalid address. + + + +
AUDIO_GET_CAPABILITIES +DESCRIPTION + + +This ioctl call asks the Audio Device to tell us about the decoding capabilities + of the audio hardware. + + +SYNOPSIS + + +int ioctl(int fd, int request = + AUDIO_GET_CAPABILITIES, unsigned int ⋆cap); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_GET_CAPABILITIES for this + command. + + +unsigned int *cap + +Returns a bit array of supported sound formats. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EFAULT + +cap points to an invalid address. + + + +
AUDIO_CLEAR_BUFFER +DESCRIPTION + + +This ioctl call asks the Audio Device to clear all software and hardware buffers + of the audio decoder device. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_CLEAR_BUFFER); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_CLEAR_BUFFER for this command. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + + +
AUDIO_SET_ID +DESCRIPTION + + +This ioctl selects which sub-stream is to be decoded if a program or system + stream is sent to the video device. If no audio stream type is set the id has to be + in [0xC0,0xDF] for MPEG sound, in [0x80,0x87] for AC3 and in [0xA0,0xA7] + for LPCM. More specifications may follow for other stream types. If the stream + type is set the id just specifies the substream id of the audio stream and only + the first 5 bits are recognized. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_SET_ID, int + id); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SET_ID for this command. + + +int id + +audio sub-stream id + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EINVAL + +Invalid sub-stream id. + + + +
AUDIO_SET_MIXER +DESCRIPTION + + +This ioctl lets you adjust the mixer settings of the audio decoder. + + +SYNOPSIS + + +int ioctl(int fd, int request = AUDIO_SET_MIXER, + audio_mixer_t ⋆mix); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SET_ID for this command. + + +audio_mixer_t *mix + +mixer settings. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor. + + +EINTERNAL + +Internal error. + + +EFAULT + +mix points to an invalid address. + + + +
AUDIO_SET_STREAMTYPE +DESCRIPTION + + +This ioctl tells the driver which kind of audio stream to expect. This is useful + if the stream offers several audio sub-streams like LPCM and AC3. + + +SYNOPSIS + + +int ioctl(fd, int request = AUDIO_SET_STREAMTYPE, + int type); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SET_STREAMTYPE for this + command. + + +int type + +stream type + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor + + +EINVAL + +type is not a valid or supported stream type. + + + +
AUDIO_SET_EXT_ID +DESCRIPTION + + +This ioctl can be used to set the extension id for MPEG streams in DVD + playback. Only the first 3 bits are recognized. + + +SYNOPSIS + + +int ioctl(fd, int request = AUDIO_SET_EXT_ID, int + id); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SET_EXT_ID for this command. + + +int id + +audio sub_stream_id + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor + + +EINVAL + +id is not a valid id. + + + +
AUDIO_SET_ATTRIBUTES +DESCRIPTION + + +This ioctl is intended for DVD playback and allows you to set certain + information about the audio stream. + + +SYNOPSIS + + +int ioctl(fd, int request = AUDIO_SET_ATTRIBUTES, + audio_attributes_t attr ); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SET_ATTRIBUTES for this command. + + +audio_attributes_t + attr + +audio attributes according to section ?? + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor + + +EINVAL + +attr is not a valid or supported attribute setting. + + + +
AUDIO_SET_KARAOKE +DESCRIPTION + + +This ioctl allows one to set the mixer settings for a karaoke DVD. + + +SYNOPSIS + + +int ioctl(fd, int request = AUDIO_SET_STREAMTYPE, + audio_karaoke_t ⋆karaoke); + + +PARAMETERS + + +int fd + +File descriptor returned by a previous call to open(). + + +int request + +Equals AUDIO_SET_STREAMTYPE for this + command. + + +audio_karaoke_t + *karaoke + +karaoke settings according to section ??. + + +ERRORS + + +EBADF + +fd is not a valid open file descriptor + + +EINVAL + +karaoke is not a valid or supported karaoke setting. + + +
+
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