For those of you using this document (the DV-to-DVD-HOWTO)... http://zebra.fh-weingarten.de/~transcode/docs/DV-to-DVD-HOWTO.txt
...if you follow the method described in it, which, essentially, is based on dvdauthor's "One chapter, one source" template... http://dvdauthor.sourceforge.net/doc/ex-title.html#AEN37 ...then perhaps you know that there are A/V sync issues if you use AC3 for sound instead of MP2. With MP2, the sync is perfect no matter what. With AC3, the sync starts drifting, the size of the drift depends on the number of chapters - the more chapters, the bigger the drift. If there are more than 5...7 chapters, the problem becomes obvious. The cause of the problem is probably manifold. There were some thread locking issues in transcode (due to ffmpeg being not thread-safe). Tilmann had some fixes for that, which were included in transcode-0.6.12, but didn't solve the problem. mplex had it's own issues with audio tracks not equal with the video tracks - in that case bad truncation occured. Scott fixed that in mjpegtools-1.6.1.93. That didn't solve the problem either. Then, dvdauthor itself tries its best to deal with audio tracks being shorter than the video tracks, filling in the gaps in a best-effort manner (i.e. "not truly always perfect"). Some bugfixes by Scott were included in dvdauthor-0.6.9, which didn't solve the problem. (It would be interesting to know why MP2 works without any issues whatsoever. I suspect the audio stream is not perfectly equal with the video stream in this case either, but probably dvdauthor does a better job in this case of filling in the gaps.) In any case, the alpha 859 version of dvdauthor made a big step forward: Scott made it reset the 'presented seamlessly' flag between cells when a gap in audio is detected. It's a hack, but it definitely fixes the AC3 A/V sync problem. On the flipside, the DVD player has a sub-second freeze in such a case (between chapters if there's an audio gap). To me, that's actually good. It provides a better visual cue that the chapter changed. But then again, i never need seamless continuation between chapters in my movies, just because of the completely disjunct nature of those chapters (and i'm too lazy to come up with a nicer scene change anyway). But i can see why some users might not like this solution. So, long story short: if you use dvdauthor-alpha-859 or newer (and also upgrade transcode and mjpegtools to the very latest), then you can use AC3 for sound encoding, but on hardware DVD players there will be a split-second pause between chapters (the last frame of the previous chapter stays on the screen for like 0.3 seconds and there's no sound for the duration). As for a software player, i tested with xine and there's no pause. -- Florin Andrei http://florin.myip.org/ ------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
