That's exactly right -- so if an AVI player works by directly addressing the video card, it will not work under VNC. When you run the AVI player directly on the server's monitor, you see the movie directly via the video card, bypassing the usual screen buffer. When you run the AVI player under VNC, VNC shows you the screen buffer, but it has no access to the video card, so you don't see the video.
--Robert > Forgive me for my ignorance, but I was under the impression that the unix > versions did nothing whatsoever with the video card? Isn't that why I can > be logged on to my home server from work, yet my wife doesn't see anything > different on the server screen itself? > > Ben > ----- Original Message ----- > From: "Jonathan Morton" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Cc: "Jerry McBride" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> > Sent: Tuesday, April 01, 2003 7:30 PM > Subject: Re: VNC & AVI files > > > > >>> Easy answer. The RFB protocol picjs up the video information before > > >>> it > > >>> gets to the videocard. this menas that the Video overlay is not > > >>> picked > > >>> up as this is done at the card. For vidoe not using overlay, VNc > > >>> refresh > > >>> rates are just to slow to mantain a stream( this is the reason Quake > > >>> sux > > >>> in a remote client) > > >> > > >> I dunno about that. On my home lan I'm able to view .avi,etc with > > >> pretty darn > > >> good results. I just wish there was an easy way to get sound from the > > >> server to > > >> the client as well as the video portion... > > > > I should probably clarify. VNC picks up screen data from the video > > card's framebuffer - so it does NOT pick it up "before" the video card. > > The reason why video doesn't show on some systems, is because such > > video is being played into a separate buffer, which is then "mixed in" > > by the video card's RAMDAC - this is often known as "overlay mode". > > > > Overlay mode is very common on modern PC-based video cards. It is > > almost universal for TV applications (since the Macintosh Quadra AV > > series, and early "feature connector" equipped SVGA cards), and > > probably DVD as well (if only for "copyright protection" *cough*). It > > is also used, to a lesser extent, for certain "ordinary" video codecs, > > but normally only the more modern ones such as MPEG and Sorenson, > > rather than Indeo and Cinepak. > > > > VNC is incapable of reading the overlay buffer. If overlay is in use, > > you will see a black, blue or purple hole (depending on your particular > > overlay implementation) where the video should be. > > > > VNC *may* be capable of playing video at an "acceptable" rate, if and > > only if the following conditions hold: > > > > - You have a fast, low-latency network - such as switched 100base-TX. > > > > - Your video card has a high-efficiency "read pixels from framebuffer" > > implementation. This is surprisingly uncommon - ATI only implemented > > this in one of their most recent Catalyst drivers. Keep up to date > > with your video and m/board drivers. Matrox and recently ATI probably > > have the best solutions in this particular field. > > > > - Your server and client have fast enough CPUs to encode and decode > > each frame *very* quickly, in addition to the server decompressing the > > video. > > > > - Your server is not using overlay mode to display the original video. > > > > -------------------------------------------------------------- > > from: Jonathan "Chromatix" Morton > > mail: [EMAIL PROTECTED] > > website: http://www.chromatix.uklinux.net/ > > tagline: The key to knowledge is not to rely on people to teach you it. > > _______________________________________________ > > VNC-List mailing list > > [EMAIL PROTECTED] > > http://www.realvnc.com/mailman/listinfo/vnc-list > _______________________________________________ > VNC-List mailing list > [EMAIL PROTECTED] > http://www.realvnc.com/mailman/listinfo/vnc-list _______________________________________________ VNC-List mailing list [EMAIL PROTECTED] http://www.realvnc.com/mailman/listinfo/vnc-list
