summaryrefslogtreecommitdiffstats
path: root/Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst')
-rw-r--r--Documentation/userspace-api/media/dvb/legacy_dvb_audio.rst1642
1 files changed, 1642 insertions, 0 deletions
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 0000000000..b46fe2becd
--- /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.