Hi, I have done some investigation recently into the comparative bit error handling of Codec2 and Opus over the air with a VHF modem. I have saved some audio files from the results which can be loaded in Audacity. Codec2 samples had a bitrate of 1400 bps, Opus samples had a bitrate of 9400 bps. Both codecs were used with a 40 ms frame duration, Opus was configured with fixed bitrate and no DTX.
For both codecs I have recorded samples with and without audio compressor on. My conclusion is that Codec2 handles bit errors in the audio stream a lot better than Opus with default settings as you can see in the wav files below. Opus has high pitch high amplitude artefacts which are difficult to listen to when bit errors are present in a default configuration. Using an aggressive audio compressor setting with Opus improves the response to bit errors quite a lot, while for Codec2 there is not much improvement added by audio compression, except for a little improved readability resulting from less dynamic range. Hope this is useful to someone. Audio samples: - no audio compression http://qradiolink.org/images/opus_errors_no_compressors.wav[1] http://qradiolink.org/images/codec2_errors_no_compressor.wav[2] - with audio compression http://qradiolink.org/images/opus_errors_with_compressors.wav[3] http://qradiolink.org/images/codec2_errors_with_compressor.wav[4] Adrian -------- [1] http://qradiolink.org/images/opus_errors_no_compressors.wav [2] http://qradiolink.org/images/codec2_errors_no_compressor.wav [3] http://qradiolink.org/images/opus_errors_with_compressors.wav [4] http://qradiolink.org/images/codec2_errors_with_compressor.wav
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