> > > 1080p > > > Mpeg 1, 2 up to 80 Mbps > > > Mpeg 4 up to 20 Mbps ( Is this really the worst case? Seems low. ) > > > H.264 up to 40 Mbps > > > > Are these right? According to my PS3 info display when playing a BluRay disk > > (XMen-3, Mpeg-2 encoded I believe), the bandwidth is 20Mbps. That's playing > > at 1080i. Assuming 1080p needs twice the bandwidth, that makes around > > 40Mbps. > > Even for MPEG2. > > > > So your figures seem a little high... I'm not sure how accurate they are, > > but > > figures I've seen show DB tops out at 48Mbps, and HDDVD at 30Mbps... (HDDVD > > uses mpeg4, while BD is mpeg2 IIUC). [Someone correct me if I'm wrong here]/
In engineering you need to design for the worst case. I have read lots of complaints about players that cannot handle high bitrate video, so this *is* a problem. Bad engineering. :-( The numbers are from http://xbitlabs.com/articles/video/display/video-playback.html If someone knows of a more authorative source for maximum bitrates please post it. If there even *is* a hard number for maximum bitrate? OTA DTV has a hard max bitrate due to available RF bandwidth, and presumably cable/sat do also. But are there hard limits on Blu-Ray and HD-DVD? On something you download from the Internet? If someone gets "artsy" and makes a video where every frame is completely different from the previous frame, it is not going to be very compressable, so the bitrate will skyrocket. And yes, people do make videos like this. (I don't like the effect, but that is a personal subjective opinion.) A real-time decoder has to handle the peak rate, not just the average rate. > isnt that the data rate for the decoded/uncompressed video stream? > maybe that bandwidth is from video framebuffer to the tv not the > compressed data from the hd dvd to cpu/memory. Uncompressed 1080 with 24 bit color is 2,985,984,000 bits/sec @60 fps minus whatever the 4:2:2 / 4:2:0 / 4:1:1 type compression gets you. Is it as simple as 4:2:2 being 8/12 and 4:2:0 & 4:1:1 being 6/12? I've read that most 1080 material was originally recorded as 24 fps progressive. If that is true, you can multiply the above figure by 24/60 to get the actual data content. It would certainly be true for most movies shot on film. If the 40 Mbps H.264 figure is correct, I fear it will be a real bear to decode in real time. :-( _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
