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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/userspace-api/media/dvb/audio_data_types.rst | |
parent | Initial commit. (diff) | |
download | linux-upstream/5.10.209.tar.xz linux-upstream/5.10.209.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | Documentation/userspace-api/media/dvb/audio_data_types.rst | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/dvb/audio_data_types.rst b/Documentation/userspace-api/media/dvb/audio_data_types.rst new file mode 100644 index 000000000..474452913 --- /dev/null +++ b/Documentation/userspace-api/media/dvb/audio_data_types.rst @@ -0,0 +1,116 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later + +.. _audio_data_types: + +**************** +Audio Data Types +**************** + +This section describes the structures, data types and defines used when +talking to the audio device. + +.. c:type:: audio_stream_source + +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. + + +.. code-block:: c + + 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. + + +.. c:type:: audio_play_state + +The following values can be returned by the AUDIO_GET_STATUS call +representing the state of audio playback. + + +.. code-block:: c + + typedef enum { + AUDIO_STOPPED, + AUDIO_PLAYING, + AUDIO_PAUSED + } audio_play_state_t; + + +.. c:type:: audio_channel_select + +The audio channel selected via AUDIO_CHANNEL_SELECT is determined by +the following values. + + +.. code-block:: c + + typedef enum { + AUDIO_STEREO, + AUDIO_MONO_LEFT, + AUDIO_MONO_RIGHT, + AUDIO_MONO, + AUDIO_STEREO_SWAPPED + } audio_channel_select_t; + + +.. c:type:: audio_status + +The AUDIO_GET_STATUS call returns the following structure informing +about various states of the playback operation. + + +.. code-block:: c + + 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_mixer_t mixer_state; + } audio_status_t; + + +.. c:type:: audio_mixer + +The following structure is used by the AUDIO_SET_MIXER call to set the +audio volume. + + +.. code-block:: c + + typedef struct audio_mixer { + unsigned int volume_left; + unsigned int volume_right; + } audio_mixer_t; + + +.. _audio_encodings: + +audio encodings +=============== + +A call to AUDIO_GET_CAPABILITIES returns an unsigned integer with the +following bits set according to the hardwares capabilities. + + +.. 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 |