Transmission error robust adpcm compressor with enhanced response

An audio communication receiver that receives an audio data stream conveying a sequence of quantized error values, the receiver comprising:

• a multiplier that uses corresponding envelope estimates to produce a sequence of reconstructed error values based on the sequence of quantized error values;
• a summation element that combines the sequence of reconstructed error values with a sequence of predicted audio sample values to produce a sequence of reconstructed audio samples;
• a predictor that produces the sequence of predicted audio sample values based on the sequence of reconstructed audio samples;
• and
• an envelope estimator including:
• an updater that applies a dynamic gain to the reconstructed error values to produce a sequence of update values;
• and
• an integrator that combines each of the update values with the corresponding envelope estimate to produce a subsequent envelope estimate.

An audio communication method that comprises:

• obtaining a sequence of quantized error values from an audio data stream;
• using corresponding envelope estimates to produce a sequence of reconstructed error values based on the sequence of quantized error values;
• combining the sequence of reconstructed error values with a sequence of predicted audio sample values to produce a sequence of reconstructed audio samples;
• producing the sequence of predicted audio sample values based on the sequence of reconstructed audio samples;
• and
• deriving the corresponding envelope estimates by:
• applying a dynamic gain to the reconstructed error values to produce a sequence of update values;
• and
• combining each of the update values with the corresponding envelope estimate to produce a subsequent envelope estimate.