Enum item ALSpeexCompressor.TALSpeexBandMode.alSpeexNarrowBand

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Package: AudioLabPkg

Unit: ALSpeexCompressor

Enum: TALSpeexBandMode

Description

This section looks at how Speex works for narrowband (8kHz sampling rate) operation.

The frame size for this mode is 20 ms, corresponding to 160 samples. Each frame is

also subdivided into 4 sub-frames of 40 samples each.

Also many design decisions were based on the original goals and assumptions:

• Minimizing the amount of information extracted from past frames (for robustness

to packet loss)

• Dynamically-selectable codebooks (LSP, pitch and innovation)

• sub-vector fixed (innovation) codebooks