From 8de1392b607bd886b0a083452b85ce7144ad372c Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Sun, 6 Sep 2009 22:25:36 -0300 Subject: dvb-spec/sgml: Finish conversion to DocBook XML 4.1.2 From: Mauro Carvalho Chehab With the conversion of both v4l2 and dvb-spec to the same DocBook version used in kernel, it is now possible to do some interesting things like adding the docs upstream and/or merge or share chapters between the two specs. Also, after promoting this version to official, just one set of text tools will be needed to generate both DVB and V4L2 specs. Yet, more work is needed to validate the conversion, improve the layout of the documents, provide cross references, etc. Signed-off-by: Mauro Carvalho Chehab --- dvb-spec/sgml/audio.sgml | 1473 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1473 insertions(+) create mode 100644 dvb-spec/sgml/audio.sgml (limited to 'dvb-spec/sgml/audio.sgml') diff --git a/dvb-spec/sgml/audio.sgml b/dvb-spec/sgml/audio.sgml new file mode 100644 index 000000000..eeb96b8a0 --- /dev/null +++ b/dvb-spec/sgml/audio.sgml @@ -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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