[pulseaudio-discuss] network audio compression

[Lennart Poettering]

On Sun, 19.07.09 09:19, Heat (attila589 at gmail.com) wrote:

> Hi!
> I was thinking about writing a module to compress the audio stream with
> lossy low latency encoder. That way it would be possible to stream the audio
> through network in very little delay, thus supporting the collaborative play
> for musicians. The codec will be CELT ( www.celt-codec.org ), as it's the
> most suitable for this task, and also very easy to use. I have downloaded
> the git source of PulseAudio, and checked the modules. What's your opinion,
> i should implement this into the network streaming module, or create a new
> module? Also what is necessary to made this and to be simple?

I have been discussing this with Jean-Marc Valin since the very early
days CELT was created, and it has always been my plan to support CELT
in PA as an codec for encoding the PCM traffic. However, I have never
actually found the time to implement that.

CELT support should probably be built directly into PA's native
protocol from the lowest level on, which is not going to be easy
though. Also, if we add CELT support we probably should support
Vorbis/Speex and other codecs, too, for enabling pass-through and for
moving codec decoding to the server side.

I see supporting AC3 pass-thru, Vorbis/Speex decompression and CELT
compression+decompression as different sides of a (three-sided...)
medal. 

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4