Very similar to this issue:

• Unexpected continuous noise when combining NoLACE with DTX #351

When decoding audio generated with 60ms packet time, there is a distinct clicking noise. This is most certainly related to the 400ms DTX interval, maybe it could be attenuated more? On iOS devices playing out the speaker, the clicking sound is very noticeable. I don't here the sound with the default 20ms packet time, but it could be there.

A very short example file (uncompress it first):
example.raw.zip

Encode with our settings (CBR, DTX, 60ms framesize):

$ ./opus_demo -e voip 48000 1 32000 -cbr -dtx -inbandfec -framesize 60 -complexity 9 example.raw example.enc

Decode it:

$ ./opus_demo -d 48000 1 example.enc example.dec

The resulting audio will contain the noise. The volume of it is very low, but it is there amongst the background noise.

Thanks!