diff options
Diffstat (limited to '')
| -rw-r--r-- | Documentation/sound/designs/compress-offload.rst | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/Documentation/sound/designs/compress-offload.rst b/Documentation/sound/designs/compress-offload.rst index ad4bfbdacc83..935f325dbc77 100644 --- a/Documentation/sound/designs/compress-offload.rst +++ b/Documentation/sound/designs/compress-offload.rst @@ -151,6 +151,57 @@ Modifications include: - Addition of encoding options when required (derived from OpenMAX IL) - Addition of rateControlSupported (missing in OpenMAX AL) +State Machine +============= + +The compressed audio stream state machine is described below :: + + +----------+ + | | + | OPEN | + | | + +----------+ + | + | + | compr_set_params() + | + v + compr_free() +----------+ + +------------------------------------| | + | | SETUP | + | +-------------------------| |<-------------------------+ + | | compr_write() +----------+ | + | | ^ | + | | | compr_drain_notify() | + | | | or | + | | | compr_stop() | + | | | | + | | +----------+ | + | | | | | + | | | DRAIN | | + | | | | | + | | +----------+ | + | | ^ | + | | | | + | | | compr_drain() | + | | | | + | v | | + | +----------+ +----------+ | + | | | compr_start() | | compr_stop() | + | | PREPARE |------------------->| RUNNING |--------------------------+ + | | | | | | + | +----------+ +----------+ | + | | | ^ | + | |compr_free() | | | + | | compr_pause() | | compr_resume() | + | | | | | + | v v | | + | +----------+ +----------+ | + | | | | | compr_stop() | + +--->| FREE | | PAUSE |---------------------------+ + | | | | + +----------+ +----------+ + Gapless Playback ================ @@ -199,6 +250,38 @@ Sequence flow for gapless would be: (note: order for partial_drain and write for next track can be reversed as well) +Gapless Playback SM +=================== + +For Gapless, we move from running state to partial drain and back, along +with setting of meta_data and signalling for next track :: + + + +----------+ + compr_drain_notify() | | + +------------------------>| RUNNING | + | | | + | +----------+ + | | + | | + | | compr_next_track() + | | + | V + | +----------+ + | | | + | |NEXT_TRACK| + | | | + | +----------+ + | | + | | + | | compr_partial_drain() + | | + | V + | +----------+ + | | | + +------------------------ | PARTIAL_ | + | DRAIN | + +----------+ Not supported ============= |