Opus DTX issue report

Hello:

We noticed that opus reconstructed noise is pulsing with a 400ms pattern when dtx is enabled in silk mode. This is independent of the background noise level and is found with speech + non-speech period test files, as well as variable level noise-only test files. This issue can be easirly reproduced with opus v1.1 using this command: ./opus_demo voip 16000 1 25000 –dtx input.bin output.bin

We have attached a .wav file with the first channel as the input reference noise signal and the second channel as the opus codec output using the opus_demo application. It does not look like this has been reported already. We would like your feedback.

Thank you, Gonzalo Mariano and Pascal Huart Cisco Systems