Algorithms

Supplied Processing Algorithms

SOF contains several permissively-licensed and royalty-free audio processing algorithms that can be used alongside proprietary processing components to build pipelines.

Table 2 Supplied Audio Processing Algorithms
Processing Description Generic C SIMD Support Status Milestone
Acoustical Echo Cancellation (mockup) Attenuates speaker originated acoustical coupling in microphone capture signal Yes N/A Planned 1.6
Asynchronous sample rate conversion Converts between common sample rates and connects pipelines with different clock domains Yes Xtensa HiFi3 Upstream 1.5
Channel selector Copies the selected channel from the source buffer to the sink buffer Yes N/A Upstream 1.4
Crossover Splits up audio into at most four different bands for individual processing Yes No Planned  
DCBlocker Simple highpass filter to remove DC components from audio Yes N/A Planned  
Demultiplexer Copies PCM sample frames from one source buffer to multiple sink buffers with configurable channels Yes N/A Upstream 1.4
Dynamic Range Processor Compresses and expands an audio signal to bring out quiet sounds and dampening loud sounds Yes Yes Planned  
FIR equalizer Enhances frequency response with a finite impulse response filter, e.g. improve speaker sound Yes Xtensa HiFi3 Upstream 1.4
IIR equalizer Enhances frequency response with an infinite impulse response filter, e.g. cancel DC component or improve speaker sound Yes Xtensa HiFi3 Upstream 1.4
Mixer Sums with unity gain and saturation source buffers of multiple pipelines to a single output sink buffer Yes No Upstream 1.0
Multi-microphone beamformer Enhances directivity of microphone array towards steer direction and attenuates diffuse noise Yes Yes Planned 1.6
PCM converter Not a dedicated component but provides for DAI and host components conversion between PCM formats e.g. S16_LE, S24_LE, and S32_LE Yes Xtensa HiFi3 Upstream 1.5
Sample rate conversion Converts between common sample rates to connect multi-rate synchronous pipelines Yes Xtensa HiFi3 Upstream 1.3
Volume Provides real-time stream gain controls to the user Yes Xtensa HiFi3 Upstream 1.0

Algorithm Specific Information

Further information on specific algorithms is forthcoming.