Re: [Qemu-devel] Re: [RFC] qemu-gui based on wxWidgets and libvncclient

[Oliver Gerlich]

Here's a partial translation/explanation of the link that Johannes sent 
some days ago, concerning remote sound in VNC. The final documentation 
(in german) can be found at 
http://www.ks.uni-freiburg.de/download/studienarbeit/SS05/08-05-TonSpur-DRichter/Dokumentation/Dokumentation.pdf

According to that PDF, sound is transmitted by capturing it with a Java 
application, then converting it using JMF (Java Media Framework) and 
sending it out as RTP stream. A Java client receives the RTP stream and 
plays it. As far as I understand, handshaking is done with an own TCP 
connection, while actual RTP packets are sent via UDP. During 
handshaking, connection speed is measured (see 6.1.2) to decide on the 
encoding (see 6.2.2).

There's also an older document at 
http://www.ks.uni-freiburg.de/download/studienarbeit/WS03/Ton-Spur-VNC.pdf 
which indeed describes a way to use ESD for remote sound.


Regards,
Oliver


Anthony Liguori wrote:
> Johannes Schindelin wrote:
> > Hi,
> >
> > On Tue, 17 Oct 2006, Fabrice Bellard wrote:
> >
> > > Another point is that you should consider adding audio support. I can 
> > > help you on that (maybe malc would be interested too !). A simple 
> > > format could be 4 bit ADPCM at fixed frequency. Optionally A more 
> > > advanced codec such as Vorbis could be used.
> >
> > Please, please not _another_ vnc hack! The RFB protocol loses all of 
> > its appeal if everybody has proprietary, incompatible extensions! If 
> > you bother to search Google for prior art, here is a link:
> >
> > http://www.ks.uni-freiburg.de/php_arbeitdet.php?id=75
> >
> > Yes, it is in German, but it already works. No need to add yet another 
> > obscure extension.
>
> My German is not very good, but from what I was able to read, it seems 
> like they are just using VNC to transmit the port information for doing 
> esd forwarding.  Presumably this saved a lot of work because no server 
> side code was needed.
>
> Regards,
>
> Anthony Liguori
>
> > Ciao,
> > Dscho
>
>
>
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