Encoding silence as VOIP results in low-level noise in output of decoder
In a scenario where speech is followed by pure silence (for example in a VoIP application where the user might mute their microphone), and DTX is disabled, it seems that the Opus (SILK) decoder generates very low-level noise (around -56dB). I am not sure whether this is a known, and potentially expected/desired behaviour, but I thought I would report it anyway. It feels that it would be nice if the transcoded output in this case could still be pure silence. This is the case if changing the application type from "voip" to "audio". Could you please comment? Many thanks.
Steps to reproduce (environment: Linux Ubuntu 18.04 64-bit, Opus 1.3.1):
./autogen.sh
./configure --enable-fixed-point --disable-doc --with-pic
./opus_demo voip 16000 1 64000 speech_and_silence.raw speech_and_silence_output.raw