nermal
9th April 2003, 04:25
Hi!
I've got some mpeg-files in VCD format (ripped episodes of a popular cartoon tv series) and instead of creating VCDs I'd like to put them all on a single DVD. There are several guides on the net that suggest to only convert the audio from 44.1 to 48 khz but keeping the video in the original format (no recompression), because it's resolution is already a valid DVD resolution (352x240 NTSC).
I demuxed the file with bbmpeg (I also tried at least four other demuxers, including tmpgenc) and noticed that with some VCD-movies the demuxed audio stream is a few seconds shorter than the video stream. When remuxing the streams (with or without audio 44.1->48 kHz conversion) the audio gets more and more out of sync as the video plays. The delay increases from zero to the length difference between video and audio.
I've read several threads about this topic, and some people said that it has something to do with "dropped frames" within the video and "anchors" that connect video and audio to make it playback in sync. When demuxing, these "anchors" get lost and the sync cannot be restored.
I stretched the demuxed audio stream to the length of the video with CoolEdit. The result was in sync at the beginning and also in sync at the end, but in the middle of the movie it was out of sync again. It seems that the playback speed of the video (framerate) varies during playback, while the audio playback is constant. I've read about that in this thread (http://virtualdub.everwicked.com/index.php?act=ST&f=14&t=2320&hl=).
The tool PVAStrumento didn't help me as it is for MPEG-2 only.
My question is now: is there any way to transform my VCD files to a DVD-compatible format without losing audio sync (and, if possible, without reencoding the video)? Is it possible to remux these files with some tool that keeps the sync?
Thanks alot!
Christoph
I've got some mpeg-files in VCD format (ripped episodes of a popular cartoon tv series) and instead of creating VCDs I'd like to put them all on a single DVD. There are several guides on the net that suggest to only convert the audio from 44.1 to 48 khz but keeping the video in the original format (no recompression), because it's resolution is already a valid DVD resolution (352x240 NTSC).
I demuxed the file with bbmpeg (I also tried at least four other demuxers, including tmpgenc) and noticed that with some VCD-movies the demuxed audio stream is a few seconds shorter than the video stream. When remuxing the streams (with or without audio 44.1->48 kHz conversion) the audio gets more and more out of sync as the video plays. The delay increases from zero to the length difference between video and audio.
I've read several threads about this topic, and some people said that it has something to do with "dropped frames" within the video and "anchors" that connect video and audio to make it playback in sync. When demuxing, these "anchors" get lost and the sync cannot be restored.
I stretched the demuxed audio stream to the length of the video with CoolEdit. The result was in sync at the beginning and also in sync at the end, but in the middle of the movie it was out of sync again. It seems that the playback speed of the video (framerate) varies during playback, while the audio playback is constant. I've read about that in this thread (http://virtualdub.everwicked.com/index.php?act=ST&f=14&t=2320&hl=).
The tool PVAStrumento didn't help me as it is for MPEG-2 only.
My question is now: is there any way to transform my VCD files to a DVD-compatible format without losing audio sync (and, if possible, without reencoding the video)? Is it possible to remux these files with some tool that keeps the sync?
Thanks alot!
Christoph