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Normalize loudness
Open, Needs TriagePublic

Description

Should LinguaLibre normalize the loudness of recordings to EBU R 128, so that pronunciations are perceived equally loud irrespective of user microphones?

ffmpeg can do this, either if you call it directly (rather painful), or via the ffmpeg-normalize wrapper script. It’s also possible to embed metadata with loudness parameters, which some (but not all) players recognize. But in the context of LinguaLibre, which does not use a lossy audio compression, it might be best to normalize loudness on the server at preprocessing time.

See discussion in the Lingua Libre chatroom for the thoughts of others.