Lines Matching +full:dynamic +full:- +full:power +full:- +full:switching
2 ALSA Compress-Offload API
5 Pierre-Louis.Bossart <pierre-[email protected]>
18 in system-on-chip designs, and DSPs are also integrated in audio
20 reduction of power consumption compared to host-based
27 provide a control and data-streaming interface for audio DSPs.
29 The design of this API was inspired by the 2-year experience with the
39 - separation between byte counts and time. Compressed formats may have
41 may vary from frame-to-frame. As a result, it is not possible to
44 reliable audio-video synchronization, which requires precise
47 - Handling of multiple formats. PCM data only requires a specification
52 dynamic download of libraries.
54 - Focus on main formats. This API provides support for the most
59 - Handling of multiple configurations. Even for a given format like
60 AAC, some implementations may support AAC multichannel but HE-AAC
65 - Rendering/Grabbing only. This API does not provide any means of
67 user-space for additional processing. This API focuses instead on
69 decoded samples are routed to a physical output or logical back-end.
71 - Complexity hiding. Existing user-space multimedia frameworks all
73 API assumes the existence of a platform-specific compatibility layer
118 dynamic and dependent on existing workloads. In addition to codec
145 - Addition of FLAC and IEC formats
146 - Merge of encoder/decoder capabilities
147 - Profiles/modes listed as bitmasks to make descriptors more compact
148 - Addition of set_params for decoders (missing in OpenMAX AL)
149 - Addition of AMR/AMR-WB encoding modes (missing in OpenMAX AL)
150 - Addition of format information for WMA
151 - Addition of encoding options when required (derived from OpenMAX IL)
152 - Addition of rateControlSupported (missing in OpenMAX AL)
159 +----------+
163 +----------+
169 compr_free() +----------+
170 +------------------------------------| |
172 | +-------------------------| |<-------------------------+
173 | | compr_write() +----------+ |
179 | | +----------+ |
183 | | +----------+ |
189 | +----------+ +----------+ |
191 | | PREPARE |------------------->| RUNNING |--------------------------+
193 | +----------+ +----------+ |
199 | +----------+ +----------+ |
201 +--->| FREE | | PAUSE |---------------------------+
203 +----------+ +----------+
211 switching from one track to another
213 Also, there might be low-intensity noises due to encoding. Perfect gapless is
238 - Open
239 - Get caps / codec caps
240 - Set params
241 - Set metadata of the first track
242 - Fill data of the first track
243 - Trigger start
244 - User-space finished sending all,
245 - Indicate next track data by sending set_next_track
246 - Set metadata of the next track
247 - then call partial_drain to flush most of buffer in DSP
248 - Fill data of the next track
249 - DSP switches to second track
260 +----------+
262 +------------------------>| RUNNING |
264 | +----------+
270 | +----------+
272 | +-----------|NEXT_TRACK|
274 | | +--+-------+
276 | +--------------+ |
281 | +----------+
283 +------------------------ | PARTIAL_ |
285 +----------+
289 - Support for VoIP/circuit-switched calls is not the target of this
290 API. Support for dynamic bit-rate changes would require a tight
291 coupling between the DSP and the host stack, limiting power savings.
293 - Packet-loss concealment is not supported. This would require an
297 - Volume control/routing is not handled by this API. Devices exposing a
302 - Embedded audio effects. Such effects should be enabled in the same
305 - multichannel IEC encoding. Unclear if this is required.
307 - Encoding/decoding acceleration is not supported as mentioned
312 - Audio policy/resource management. This API does not provide any
316 - No notion of underrun/overrun. Since the bytes written are compressed
319 maybe dealt in user-library
324 - Mark Brown and Liam Girdwood for discussions on the need for this API
325 - Harsha Priya for her work on intel_sst compressed API
326 - Rakesh Ughreja for valuable feedback
327 - Sing Nallasellan, Sikkandar Madar and Prasanna Samaga for