On Thu, May 28, 2009 at 01:54:20PM +0200, Pierre Ossman wrote: > > I belive the problem is that WMVi is fundamentally broken. RFB is all > about putting complexity at the server and letting the client use > whatever formats it wants. As such, WMVi will always be a pain to > handle for clients, > > What should be done is to have an extension where the server informs > the client of the server pixfmt, not shoves it down the client's > throat. A client can then decide on its own if it wants/can follow this > change.
IIUC, forcing it on the client is an explicit goal of this extension. Historically the VNC server associated with a virtual machine has had to maintain a duplicate copy of the video RAM, track changes between the guest and what the VNC client has, and do pixel format conversions. This imposes both a memory and CPU overhead on the host, which becomes non-negligble with lots of guest machines running on a single host. With the WMVi extension enabled, the VNC client is set to always have its framebuffer in exactly the same format as the guest OS has. In combination with elimination of the video RAM duplicate, the VNC server now avoids the memory & CPU overheads, pushing these conversion out to each individual client. NB, this is assuming you have a low latency, high bandwidth link between client & server, but that's not totally unreasonable given the goal of this extension is to push resource utilization off the server to the client - which is sort of an opposite goal to traditional VNC desktop scenarios. As such it wouldn't make sense to recommend use of WMVi extension for most VNC servers, where the more common goal is to keep the overhead/complexity in the server. Regards, Daniel -- |: http://berrange.com/ -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://freshmeat.net/~danielpb/ -o- http://gtk-vnc.sourceforge.net :| ------------------------------------------------------------------------------ Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers & brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, & iPhoneDevCamp as they present alongside digital heavyweights like Barbarian Group, R/GA, & Big Spaceship. http://p.sf.net/sfu/creativitycat-com _______________________________________________ tigervnc-rfbproto mailing list tigervnc-rfbproto@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tigervnc-rfbproto
