On Mon, Dec 12, 2011 at 09:46:17AM -0500, Steven Carr wrote: > On Monday 12 December 2011 09:35:11 Daniel P. Berrange wrote: > > On Mon, Dec 12, 2011 at 02:27:51PM +0100, Gerd Hoffmann wrote: > > > One fundamental issue the vnc audio extension has is that both audio and > > > video travel over the same tcp pipe. So a bulky screen update can > > > easily disturb audio playback by delaying the audio stream. With slower > > > network it will be more noticeable of course. > > > > Yeah, I'm not really expecting this VNC audio support to be a serious > > alternative to SPICE with audio. It was still nice to have the audio > > support in GTK-VNC though > > I actually run 3 or 4 VM's on the same machine as the viewer. > > I do not think that the VNC protocol is significantly different than the MP4 > protocol. Both can interlace audio/video data. And both can provide a > quality experience. In my opinion, it is really up to the *encoder* to > ensure that the audio/video is multiplexed appropriately in the stream so that > the client can properly decode things. VNC protocol has the added benefit > that the server can detect how powerful the client/network is via measuring > the latency of updates. It is my opinion that if the MPEG protocol can do > it, so can the VNC protocol. > > Alternatively, the gtk-vnc client *could* make a second VNC connection to > the same server, log-in, negotiate audio encodings, and not perform framebuffer > requests. Just listen for audio (or request 1 pixel updates or something > like that). A dual connection approach that is also compatible with a single > connection approach. Sure, the QEMU server could be improved to cope better with audio vs large framebuffer updates, and the Audio-over-VNC protocol could be improved too. Given the inclusion of SPICE in QEMU though, I just don't see many developers caring enough to want todo this for VNC. The main benefit of VNC over SPICE is that VNC clients are widely deployed / available. This benefit is lost though in the context of audio-over-VNC since it is a custom extension defined by QEMU which few VNC clients implement. As such I think SPICE really has the upper hand for the future. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
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