| .. 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. |
