Am Montag 30 Juli 2007 01:48 schrieb Ben Blout: [...] > >I have a NTSC DVD and want to create a PAL DVD from it. > >I copied the VOBs to my disk using dvdunauthor. Then I used > >the following command to convert video to 25fps: > > > >transcode -i vob_01t_001.vob -x vob,null -a 0,0 \ > >-y mpeg2enc,null -F8 -w 7800 -J modfps --export_fps 25 \ > >--export_asr 2 --export_prof dvd_pal -o my_output > > > >This produces my_output.m2v with 25fps in good quality. > >(Ben, does this work for you?) > > You have one error in the command line > you need dvd-pal, not dvd_pal. > [shouldn't transcode report an error?]
Thanks for that hint! No, transcode doesn't report an error. It simply ignores that option. In fact, I got 720x480 instead of 720x576. With the correct syntax, everything is fine. > > do you see a line like > [filter_modfps.so] converting from 29.9700fps to 25.0000fps Yes, and tcprobe (and other applications) report 25fps for the resulting video. [...] > >I then used mplayer -dumpaudio to get the stream. > >This worked. But although the audio file has exactly > >the same length as my converted video (within a few > >10 milliseconds), I didn't manage to get it in sync > >with my video. After about 3600 frames (2 min 24 sec), > >audio is already one second behind the video. This > >further increases towards the end of the video. > >Audio is simply played too slow, which means the > >player has a lot of audio left when the video ends. > > If you play the audio and video separately, are they both the same > length? Yes, within a few 100 milliseconds. > > My guess is that your video is 25fps being played at ntsc (29.9xxx) > frames per second. But that is a guess. No, the difference is much less, only about 0.6%. It seems to be some kind of round-off error. I made another experiment: I took a scene near the end of the movie where I could exactly determine the delay (a shot from a gun...), and changed the tempo of the sound file accordingly using audacity's "Change Tempo" effect. The result is that now audio and video are in sync at the beginning and at the end of the video, but not in the middle. That means the delay error is not constant. As I took audio from the original VOB, it can only mean that transcode's 29.97 to 25 fps conversion algorithm is broken and slightly changes the speed up and down during conversion. No chance to get audio in sync with that. > > >How can that be explained? If I multiplex one hour > >of video with one hour of audio, how can they be > >out-of-sync? > > They really can't be. Yes, they can. Any other way of converting NTSC to PAL I could try? Thanks, Hans
