3 ms·

Basically all audio codecs meant for real time communication are built to maintain constant but rate — because even though it is nice to save a few bits occasio

Basically all audio codecs meant for real time communication are built to maintain constant but rate — because even though it is nice to save a few bits occasionally when you can, you can’t use present silence to encode future speech (you haven’t heard it yet...); So, no. The filler is part of the protocol and is not undoing any of the PCM compression; silence would let you compress the stream more than the plain voice codec would - and THAT would interact with encryption. But that’s quite unusual for real time systems.

corty 6y ago
Not really. Silence is encoded with silence frames containing just a length of silence marker in most VoIP protocols. On the receiving end, silence frames are then filled with "comfort noise". If you pay attention and have a crappy phone you can hear this, because the comfort noise generator will produce noticably different "silence". Yes, one often does CBR, but even there, variable difficulty of compression often produces variable jitter, which can then be used to infer information about the plaintext stream. There are constant runtime CBR codecs, but one has to take care to use them.