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diff --git a/Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst b/Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst new file mode 100644 index 000000000000..b46fe2becd02 --- /dev/null +++ b/Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst @@ -0,0 +1,1642 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later OR GPL-2.0 + +.. c:namespace:: dtv.legacy.audio + +.. _dvb_audio: + +================ +DVB Audio Device +================ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +The DVB audio device controls the MPEG2 audio decoder of the DVB +hardware. It can be accessed through ``/dev/dvb/adapter?/audio?``. Data +types and ioctl definitions can be accessed by including +``linux/dvb/audio.h`` in your application. + +Please note that most DVB cards don’t have their own MPEG decoder, which +results in the omission of the audio and video 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<audio>` for new drivers! + + +Audio Data Types +================ + +This section describes the structures, data types and defines used when +talking to the audio device. + + +----- + + +audio_stream_source_t +--------------------- + +Synopsis +~~~~~~~~ + +.. c:enum:: audio_stream_source_t + +.. code-block:: c + + typedef enum { + AUDIO_SOURCE_DEMUX, + AUDIO_SOURCE_MEMORY + } audio_stream_source_t; + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``AUDIO_SOURCE_DEMUX`` + + - :cspan:`1` Selects the demultiplexer (fed either by the frontend + or the DVR device) as the source of the video stream. + + - .. + + - ``AUDIO_SOURCE_MEMORY`` + + - Selects the stream from the application that comes through + the `write()`_ system call. + +Description +~~~~~~~~~~~ + +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. + +The data fed to the decoder is also controlled by the PID-filter. +Output selection: :c:type:`dmx_output` ``DMX_OUT_DECODER``. + + +----- + + +audio_play_state_t +------------------ + +Synopsis +~~~~~~~~ + +.. c:enum:: audio_play_state_t + +.. code-block:: c + + typedef enum { + AUDIO_STOPPED, + AUDIO_PLAYING, + AUDIO_PAUSED + } audio_play_state_t; + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``AUDIO_STOPPED`` + + - Audio is stopped. + + - .. + + - ``AUDIO_PLAYING`` + + - Audio is currently playing. + + - .. + + - ``AUDIO_PAUSE`` + + - Audio is frozen. + +Description +~~~~~~~~~~~ + +This values can be returned by the `AUDIO_GET_STATUS`_ call +representing the state of audio playback. + + +----- + + +audio_channel_select_t +---------------------- + +Synopsis +~~~~~~~~ + +.. c:enum:: audio_channel_select_t + +.. code-block:: c + + typedef enum { + AUDIO_STEREO, + AUDIO_MONO_LEFT, + AUDIO_MONO_RIGHT, + AUDIO_MONO, + AUDIO_STEREO_SWAPPED + } audio_channel_select_t; + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``AUDIO_STEREO`` + + - Stereo. + + - .. + + - ``AUDIO_MONO_LEFT`` + + - Mono, select left stereo channel as source. + + - .. + + - ``AUDIO_MONO_RIGHT`` + + - Mono, select right stereo channel as source. + + - .. + + - ``AUDIO_MONO`` + + - Mono source only. + + - .. + + - ``AUDIO_STEREO_SWAPPED`` + + - Stereo, swap L & R. + +Description +~~~~~~~~~~~ + +The audio channel selected via `AUDIO_CHANNEL_SELECT`_ is determined by +this values. + + +----- + + +audio_mixer_t +------------- + +Synopsis +~~~~~~~~ + +.. c:struct:: audio_mixer + +.. code-block:: c + + typedef struct audio_mixer { + unsigned int volume_left; + unsigned int volume_right; + } audio_mixer_t; + +Variables +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``unsigned int volume_left`` + + - Volume left channel. + Valid range: 0 ... 255 + + - .. + + - ``unsigned int volume_right`` + + - Volume right channel. + Valid range: 0 ... 255 + +Description +~~~~~~~~~~~ + +This structure is used by the `AUDIO_SET_MIXER`_ call to set the +audio volume. + + +----- + + +audio_status +------------ + +Synopsis +~~~~~~~~ + +.. c:struct:: audio_status + +.. code-block:: c + + typedef struct audio_status { + int AV_sync_state; + int mute_state; + audio_play_state_t play_state; + audio_stream_source_t stream_source; + audio_channel_select_t channel_select; + int bypass_mode; + audio_mixer_t mixer_state; + } audio_status_t; + +Variables +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - :rspan:`2` ``int AV_sync_state`` + + - :cspan:`1` Shows if A/V synchronization is ON or OFF. + + - .. + + - TRUE ( != 0 ) + + - AV-sync ON. + + - .. + + - FALSE ( == 0 ) + + - AV-sync OFF. + + - .. + + - :rspan:`2` ``int mute_state`` + + - :cspan:`1` Indicates if audio is muted or not. + + - .. + + - TRUE ( != 0 ) + + - mute audio + + - .. + + - FALSE ( == 0 ) + + - unmute audio + + - .. + + - `audio_play_state_t`_ ``play_state`` + + - Current playback state. + + - .. + + - `audio_stream_source_t`_ ``stream_source`` + + - Current source of the data. + + - .. + + - :rspan:`2` ``int bypass_mode`` + + - :cspan:`1` Is the decoding of the current Audio stream in + the DVB subsystem enabled or disabled. + + - .. + + - TRUE ( != 0 ) + + - Bypass disabled. + + - .. + + - FALSE ( == 0 ) + + - Bypass enabled. + + - .. + + - `audio_mixer_t`_ ``mixer_state`` + + - Current volume settings. + +Description +~~~~~~~~~~~ + +The `AUDIO_GET_STATUS`_ call returns this structure as information +about various states of the playback operation. + + +----- + + +audio encodings +--------------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + #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 + +Constants +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``AUDIO_CAP_DTS`` + + - :cspan:`1` The hardware accepts DTS audio tracks. + + - .. + + - ``AUDIO_CAP_LPCM`` + + - The hardware accepts uncompressed audio with + Linear Pulse-Code Modulation (LPCM) + + - .. + + - ``AUDIO_CAP_MP1`` + + - The hardware accepts MPEG-1 Audio Layer 1. + + - .. + + - ``AUDIO_CAP_MP2`` + + - The hardware accepts MPEG-1 Audio Layer 2. + Also known as MUSICAM. + + - .. + + - ``AUDIO_CAP_MP3`` + + - The hardware accepts MPEG-1 Audio Layer III. + Commomly known as .mp3. + + - .. + + - ``AUDIO_CAP_AAC`` + + - The hardware accepts AAC (Advanced Audio Coding). + + - .. + + - ``AUDIO_CAP_OGG`` + + - The hardware accepts Vorbis audio tracks. + + - .. + + - ``AUDIO_CAP_SDDS`` + + - The hardware accepts Sony Dynamic Digital Sound (SDDS). + + - .. + + - ``AUDIO_CAP_AC3`` + + - The hardware accepts Dolby Digital ATSC A/52 audio. + Also known as AC-3. + +Description +~~~~~~~~~~~ + +A call to `AUDIO_GET_CAPABILITIES`_ returns an unsigned integer with the +following bits set according to the hardwares capabilities. + + +----- + + +Audio Function Calls +==================== + + +AUDIO_STOP +---------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_STOP + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_STOP) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - File descriptor returned by a previous call to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_STOP`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to stop playing the current +stream. + +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. + + +----- + + +AUDIO_PLAY +---------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_PLAY + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_PLAY) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - File descriptor returned by a previous call to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_PLAY`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to start playing an audio stream +from the selected source. + +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. + + +----- + + +AUDIO_PAUSE +----------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_PAUSE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_PAUSE) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_PAUSE`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +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. + +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. + + +----- + + +AUDIO_CONTINUE +-------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_CONTINUE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_CONTINUE) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_CONTINUE`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl restarts the decoding and playing process previously paused +with `AUDIO_PAUSE`_ command. + +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. + + +----- + + +AUDIO_SELECT_SOURCE +------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SELECT_SOURCE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SELECT_SOURCE, + audio_stream_source_t source) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` 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. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +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. If ``AUDIO_SOURCE_DEMUX`` is selected, the data +is directly transferred from the onboard demux-device to the decoder. +Note: This only supports DVB-devices with one demux and one decoder so far. + +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. + + +----- + + +AUDIO_SET_MUTE +-------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_MUTE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_MUTE, int state) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_SET_MUTE`` for this command. + + - .. + + - :rspan:`2` ``int state`` + + - :cspan:`1` Indicates if audio device shall mute or not. + + - .. + + - TRUE ( != 0 ) + + - mute audio + + - .. + + - FALSE ( == 0 ) + + - unmute audio + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl is for DVB devices only. To control a V4L2 decoder use the +V4L2 :ref:`VIDIOC_DECODER_CMD` with the +``V4L2_DEC_CMD_START_MUTE_AUDIO`` flag instead. + +This ioctl call asks the audio device to mute the stream that is +currently being played. + +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. + + +----- + + +AUDIO_SET_AV_SYNC +----------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_AV_SYNC + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_AV_SYNC, int state) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_AV_SYNC`` for this command. + + - .. + + - :rspan:`2` ``int state`` + + - :cspan:`1` Tells the DVB subsystem if A/V synchronization + shall be ON or OFF. + + - .. + + - TRUE ( != 0 ) + + - AV-sync ON. + + - .. + + - FALSE ( == 0 ) + + - AV-sync OFF. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to turn ON or OFF A/V +synchronization. + +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. + + +----- + + +AUDIO_SET_BYPASS_MODE +--------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_BYPASS_MODE + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_BYPASS_MODE, int mode) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - :cspan:`1` Equals ``AUDIO_SET_BYPASS_MODE`` for this command. + + - .. + + - :rspan:`2` ``int mode`` + + - :cspan:`1` Enables or disables the decoding of the current + Audio stream in the DVB subsystem. + - .. + + - TRUE ( != 0 ) + + - Disable bypass + + - .. + + - FALSE ( == 0 ) + + - Enable bypass + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +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. + +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. + + +----- + + +AUDIO_CHANNEL_SELECT +-------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_CHANNEL_SELECT + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_CHANNEL_SELECT, + audio_channel_select_t) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` 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). + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl is for DVB devices only. To control a V4L2 decoder use the +V4L2 ``V4L2_CID_MPEG_AUDIO_DEC_PLAYBACK`` control instead. + +This ioctl call asks the Audio Device to select the requested channel if +possible. + +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. + + +----- + + +AUDIO_GET_STATUS +---------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_GET_STATUS + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_GET_STATUS, + struct audio_status *status) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` 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. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to return the current state of the +Audio Device. + +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. + + +----- + + +AUDIO_GET_CAPABILITIES +---------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_GET_CAPABILITIES + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_GET_CAPABILITIES, + unsigned int *cap) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` 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. + Bits are defined in `audio encodings`_. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to tell us about the decoding +capabilities of the audio hardware. + +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. + + +----- + + +AUDIO_CLEAR_BUFFER +------------------ + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_CLEAR_BUFFER + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_CLEAR_BUFFER) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_CLEAR_BUFFER`` for this command. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl call asks the Audio Device to clear all software and hardware +buffers of the audio decoder device. + +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. + + +----- + + +AUDIO_SET_ID +------------ + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_ID + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_ID, int id) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_SET_ID`` for this command. + + - .. + + - ``int id`` + + - Audio sub-stream id. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +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 range [0xC0,0xDF] +for MPEG sound, in [0x80,0x87] for AC3 and in [0xA0,0xA7] for LPCM. +See ITU-T H.222.0 | ISO/IEC 13818-1 for further description. + +If the stream type is set with `AUDIO_SET_STREAMTYPE`_, specifies the +id just the sub-stream id of the audio stream and only the first 5 bits +(& 0x1F) are recognized. + +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. + + +----- + + +AUDIO_SET_MIXER +--------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_MIXER + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_SET_MIXER, audio_mixer_t *mix) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_SET_MIXER`` for this command. + + - .. + + - ``audio_mixer_t *mix`` + + - Mixer settings. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl lets you adjust the mixer settings of the audio decoder. + +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. + + +----- + + +AUDIO_SET_STREAMTYPE +-------------------- + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_SET_STREAMTYPE + +.. code-block:: c + + int ioctl(fd, int request = AUDIO_SET_STREAMTYPE, int type) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_SET_STREAMTYPE`` for this command. + + - .. + + - ``int type`` + + - Stream type. + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +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. + +Stream types defined in ITU-T H.222.0 | ISO/IEC 13818-1 are used. + + +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. + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``EINVAL`` + + - Type is not a valid or supported stream type. + + +----- + + +AUDIO_BILINGUAL_CHANNEL_SELECT +------------------------------ + +Synopsis +~~~~~~~~ + +.. c:macro:: AUDIO_BILINGUAL_CHANNEL_SELECT + +.. code-block:: c + + int ioctl(int fd, int request = AUDIO_BILINGUAL_CHANNEL_SELECT, + audio_channel_select_t) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + + - .. + + - ``int request`` + + - Equals ``AUDIO_BILINGUAL_CHANNEL_SELECT`` for this command. + + - .. + + - ``audio_channel_select_t ch`` + + - Select the output format of the audio (mono left/right, stereo). + +Description +~~~~~~~~~~~ + +.. attention:: Do **not** use in new drivers! + See: :ref:`legacy_dvb_decoder_notes` + +This ioctl has been replaced by the V4L2 +``V4L2_CID_MPEG_AUDIO_DEC_MULTILINGUAL_PLAYBACK`` control +for MPEG decoders controlled through V4L2. + +This ioctl call asks the Audio Device to select the requested channel +for bilingual streams if possible. + +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. + + +----- + + +open() +------ + +Synopsis +~~~~~~~~ + +.. code-block:: c + + #include <fcntl.h> + +.. c:function:: int open(const char *deviceName, int flags) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``const char *deviceName`` + + - Name of specific audio device. + + - .. + + - :rspan:`3` ``int flags`` + + - :cspan:`1` 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) + +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. + +Return Value +~~~~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``ENODEV`` + + - Device driver not loaded/available. + + - .. + + - ``EBUSY`` + + - Device or resource busy. + + - .. + + - ``EINVAL`` + + - Invalid argument. + + +----- + + +close() +------- + +Synopsis +~~~~~~~~ + +.. c:function:: int close(int fd) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` File descriptor returned by a previous call + to `open()`_. + +Description +~~~~~~~~~~~ + +This system call closes a previously opened audio device. + +Return Value +~~~~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``EBADF`` + + - Fd is not a valid open file descriptor. + +----- + + +write() +------- + +Synopsis +~~~~~~~~ + +.. code-block:: c + + size_t write(int fd, const void *buf, size_t count) + +Arguments +~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``int fd`` + + - :cspan:`1` 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. + +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. + +Return Value +~~~~~~~~~~~~ + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + - .. + + - ``EPERM`` + + - :cspan:`1` 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. |