Video Stuttering With Ac3 Sound... Options

[stholt]

Anyone else been having issues with divx/xvid files with 5.1 ac3 sound? It seems like every way I try to get this to work, while watching it streamed over a network hardline through WMP11, about every five minutes or so the video stutters/skips for a second or two and then it's fine. I've demuxed the video and converted the ac3 to a stereo mp3 and remuxed it and the whole thing plays just fine(I've done this on more than one source), so i figure it's something with the divx/xvid/ac3 "support" MS has given us. Any thoughts? I usually use VirtualDubMod for the muxing, is there a better program out there? I like to use divx/avid because I get almost realtime encoding with great quality, whereas WMV takes 12-15 hours to encode.

[reddragon72]

Ok first read up here on some issues with openDML http://www.alexander-noe.com/video/amg/en_about_opendml.html then go here and read through all the issues that they had with the XBMP http://forums.afterdawn.com/thread_view.cfm/229672 that will give you some insight as to how crappy and shoddy the openDML extention is.

I have however made a small breakthrough. I have produced an Xvid-HS(1280x544) vid with AC3 5.1ch that does not skip! BUT....... it is not smooth, you can tell that there is a framerate issue in there somewhere as it kinda skips a frame every 4 seconds, it is noticable, but not entirely a killer... My problem with this output is that it is not perfect, and it uses VBR with spike in the 12000k range and the movie never skips a beat. so now I have to figure out why the video is skipping one frame every 4 seconds or so.

I use nandub to meld Xvid and AC3 files together. it is super easy and takes no time at all.

Also MS resonded to my question as to the skipping in Xvid AC3 videos and they said "We have no issues using our encoding method and keeping within the bitrates provided in the December update FAQ."

well now I emeailed them back asking them about there method and what length the video was, we shall see what they have to say about that.

[Dat720]

so now I have to figure out why the video is skipping one frame every 4 seconds or so.

You video is skipping because you have applied frame rate conversion, i would think you have converted a 23.976fps video to a 25fps video, for this frame rate conversion the encoder has to insert a duplicate frame or 2 to pad the video upto 25fps, generally i would pretty much leave the frame rate alone, unless for instance it had to be convert from a ntsc film to a pal dvd which would require a frame rate conversion...

anyway getting to my orginal intent for this post, i do not think the skipping issue is to do with a bug in ac3 5.1ch audio i think it is a issue with the hardware itself, My transformers HD DVD rip 11mbps 1920x800 256k mp3 (behaves the same with ac3 2.0 and 5.1) 12gb avi that exhibits these issues, even if i reencode at 1280x534 at high bitrate it skips, it seems to stop skipping when the bitrate goes low, below about 6-7mbps it must be a hardware constraint, either not having enough memory or gpu not being fast enough to decode and playback a high bitrate video, even my Pentium D 3.2ghz 2gb ram 512mb ati 2400pro pc has problems with video at this res and bitrate