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.