[CELT-dev] adding celt support to netjack some questions.

"Alexander Carôt" alexander_carot at gmx.net
Tue Nov 25 05:20:53 PST 2008

> I guess I'll have to think about it. Last time I checked, I found that
> there was no gain in going above 512-sample frames because you easily
> get pre-echo and the pitch predictor no longer works. Of course, one
> possibility would be to pretend we're using 1024-sample frames and just
> pack two 512-sample frames per packet.

Yes, this is what I do with the ULD, which only works with 128 samples i.e. Nevertheless it is more convenient in terms of the actual implementation if the codec supports other modi as CELT does. Well, it really not that important, simply more convenient.

> Why not use a jitter buffer along with a smaller audio buffer. If you
> look at the celtclient code (in the main repo under tools/), I use a
> jitter buffer with just 256 sample audio buffer (could be made even
> smaller). That would also help you handle lost/reordered/late packets
> correctly. Also, it means that you can handle any amount of jitter
> (adaptively) without requiring a large soundcard buffer.

Yes, that is also the way I do it. Run the card with a framing as low as possible, collect the codec specific amount, send it and receive with a manually adjusted jitter buffer. One question: How does your adaption of the buffer work ? If the size changes doesn't it imply dropping a certain amount of audio buffers ?

-- A l e x
Dipl.-Ing. Alexander Carôt
PhD Candidate
Email : Alexander at Carot.de
Tel.: +49 (0)177 5719797

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