On Thu, Dec 31, 2009 at 13:25, Kieran Kunhya <[email protected]> wrote: >> > This is windows-only right now (presumably because >> Apple won't give Adobe access to the necessary APIs). >> >> Er, what? Where did that presumption come from? >> >> Nothing else on the Mac or Linux has a problem with video >> compositing. >> VLC, which does it entirely in software too, has _no_ >> issues. Quartz, >> QuickTime, and OpenGL, which can be hardware-accelerated, >> are >> thoroughly documented. > > > GPU vendor agnostic H.264 bitstream decoding on Macs is only possible with > Quicktime - there is no public API for H.264 bitstreaming as far as I know. > Such a thing is not possible with Linux. (There are only separate vendor APIs > on Linux such as VDPAU) > > Compositing is done on the GPU in VLC (as part of whatever renderer VLC uses > - VMR9 on windows if I recall correctly) whereas in Flash it's a slow > software based YV12->RGB conversion in order for overlaying text/graphics > amongst other things. Also various issues with running inside a browser > window slow it down.
Right. The decoding is largely a non-issue. The issue is the compositing engine. Essentially: a) VLC, when _not_ using the GPU, doesn’t struggle remotely as much as Flash b) VLC also overlays text and graphics over video c) YV12->RGB _can_ be tightly optimised if you’re crazy enough to do things that way around The key there is that the YV12->RGB conversion that Flash does is slow, rather than it necessarily being software (i.e., it could be relatively efficient and still software). Either way, of course, it’s still Adobe’s problem, and was Macromedia’s before that, and one either could have expended significant resources improving upon when it was decided to position Flash as a universal video playback platform. Frankly, the sooner the codec mess behind <video /> gets sorted out and Flash can be avoided in the few remaining contexts that it’s used, the better. M. - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/[email protected]/
