Loud static noise generated by decoder when encoding using Auto signal type and DTX mode for Opus 1.3.1.

Open kingweih opened this issue 3 years ago • 1 comments

Loud static noise is generated after certain type of audio content followed by (digital) silence is being encoded. I've attached the image of the input and output waveforms. Debugging shows the encoder transitions from hybrid to CELT mode during DTX. Upon 20th frame, the encoder encodes in CELT mode. The decoder receives the CELT packet and decodes subsequently causing a reset of the CELT state (https://github.com/xiph/opus/blob/master/src/opus_decoder.c#L516) and then generates noise (https://github.com/xiph/opus/blob/master/celt/celt_decoder.c#L538) while in PLC mode.

The encoder parameters are the following: signal type = auto dtx = enabled frame length/size = 60 sample rate = 48000 max playback rate = 24000 vbr = enabled bitrate = 32000 complexity = 10 Compiled in fixed point.

I've attached the audio wave files for reproduction: noise.zip

Jun 16 '22 03:06 kingweih

Thanks for the report. This has been fixed by 8101b33e6c59b51b22aeeeaf39045e34a402b01f and 63855aff731dcf58875c159dc2fa7463a444d617.

Jun 26 '22 18:06 mark4o