google / lyra

A Very Low-Bitrate Codec for Speech Compression
Apache License 2.0
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Enhance Lyra Quality on μ-Law Decoded Audio Stream #145

Open shlomiez opened 5 months ago

shlomiez commented 5 months ago

I am currently working with Lyra on an audio stream that has been decoded from μ-law (u-law) encoding for VoIP application. Maybe because Lyra was not trained on μ-law decoded samples, the quality of the output, assessed both by listening and using the PESQ test, results in a mean score of approximately 2.4 for the 3200 bitrate mode (It's even less than codec2 results on same input 😭). I am seeking ways to improve the quality of the results.

Current Setup:

Input: μ-law encoded audio stream. Decoding: μ-law to signed 16 bit PCM using audioop. Lyra-Encoding: Lyra for further processing. --Sending Lyra-encoded packets-- Lyra-Decoding. μ-law Encoding.

Challenges: The decoded audio lacks clarity, resulting in suboptimal PESQ scores. The audio output could be more intelligible and natural (at the moment the audio output sounds a bit hoarse.).

Request for Suggestions: I am looking for advice or techniques that could help improve the quality of the audio output, potentially through: Adjustments to the u-law decoding process. Any other relevant enhancements to the Lyra configuration or processing. Thank you for your help! 🙌