Looks like I was chasing ghosts (or my own tail) with this one. Seems the table of contents file was corrupt. When I manually created a table of contents for my HDV source file, the render worked properly.
Ugh. What a lovely way to spend three evenings. thanks for the help. scott On Thu, 2007-02-08 at 14:18 +0000, [EMAIL PROTECTED] wrote: > Jonathan, > Thank you for taking the time to write out a detailed response. My responses > are below. > scott > > >>I'll have to take your word for it; the waveforms as presented are rather > >>difficult to use to verify sync. > The drummer's snare hit should be clear enough to see. > > >>Hmm, I assume you mean 48 kHz. > Sorry..too long working with CDs (44.1kHz) > > >>One question before we start. Was your multitrack and camera synced to the > >>same clock during the recording session (be it word clock, smtpe etc)? > No. > > >>the end. The only way to resolve this with unlocked sources is to > >>resample the audio from the multitrack in such a way that you correct for > >>the subtle clock differences of the gear used. > Wouldn't this difference show up in Cinelerra? > > >> http://www.physics.adelaide.edu.au/~jwoithe/audiosync-0.4.tgz > I will try your program out..definetly. Thank you for the detailed > explanation! > > >>As far as the software you need to work out the sample number of these > >>events I use audacity. > That is a good idea..I will load up both audio files and see about syncing > them there. > > >>This seems rather strange. If there's a sync problem you should hear it in > >>cinelerra unless for some odd reason the tracks aren't always being mixed. > >>I must admit that I do *all* my audio mixing in ardour (I export the camera > >>audio to WAV, import that to ardour and then sync off that), so have no > >>experience doing multitrack audio mixes in cinelerra. > Strange indeed..I would think we should hear it in Cin as well. > > >>>> sync.mov: Xine shows sync problems, mplayer no problems > >>>> sync.mpg: Xine shows no sync problems, mplayer shows problems > > >>That sounds bizarre. While you can get sync problems in certain situations > >>with different AV container formats this would cause the entire audio track > >>to drift out of sync. As I understand it from your opening statements, > >>"sync problem" here refers to an audible echo indicating one source track > >>being out of sync with the other. > I should clarify that when I say sync, I mean the synchronization between the > audio from the multitrack recording to the video. In my case, the sync looks > good in Cinelerra, but not in the rendered output. > > I will let you know how I fare after work tonight. > scott > > email message attachment > On Thu, 2007-02-08 at 14:18 +0000, [EMAIL PROTECTED] wrote: > > email message attachment, "Forwarded message - [CinCVS] Re: audio > > sync problem on rendered output, but not when viewing in compositor" > > On Thu, 2007-02-08 at 14:18 +0000, [EMAIL PROTECTED] wrote: > > > > I'm having a problem with the audio sync on a rendered video. This is a > > > > video of a rock band playing. I have used the original audio from the > > > > cam (720P HDV, MPEGTS, 48.1khz audio) to sync up a multi-track recording > > > > of the same session (WAV, 48.1khz audio). When reviewing the audio > > > > waveform in Cinelerra, the new and old audio tracks align perfectly: > > > > http://content.serveftp.net/video/sync_audioalignment.png > > > > > > I'll have to take your word for it; the waveforms as presented are rather > > > difficult to use to verify sync. The other thing to note that at least at > > > the scale in the above screen grab, two tracks can *look* in sync but > > > be far enough out to make the sync mismatch audible. > > > > > > Hmm, I assume you mean 48 kHz. > > > > > > One question before we start. Was your multitrack and camera synced to > > > the > > > same clock during the recording session (be it word clock, smtpe etc)? If > > > not, the reality is that the sampling of your multitrack and that of > > > the camera audio will differ slightly. The difference might not be large, > > > but even over 4 minutes I would expect a detectable sync problem towards > > > the end. The only way to resolve this with unlocked sources is to > > > resample the audio from the multitrack in such a way that you correct for > > > the subtle clock differences of the gear used. > > > > > > I routinely do this kind of thing and wrote a program to do this > > > resampling. > > > You can check it out at > > > > > > http://www.physics.adelaide.edu.au/~jwoithe/audiosync-0.4.tgz > > > > > > It's quick and dirty but does the job for me. In the context of your > > > job you would pick to points in the recordings which are easily > > > identifiable > > > in both waveforms - preferably at the start and end of the audio. You > > > then > > > work out the exact sample number that this event corresponds to. While > > > this > > > can be easy for direct audio (from the multitrack in your case) room > > > reverb > > > can make picking events difficult in the camera audio (unless you piped > > > the direct sound into the camera as well). Usually I pick things like the > > > snare hits, for obvious reasons. These sample numbers are then used by > > > audiosync to resample the multitrack recordings so those events line up > > > exactly. So long as you've chosen accurate samples you will end up with > > > very good sync over the long term (for example, using this method I > > > often achieve synchronisation to within 10 samples over a period of 90 > > > minutes). > > > > > > As far as the software you need to work out the sample number of these > > > events I use audacity. I set it to work directly with the audio files > > > since > > > it loads the files much quicker (although with only 4 minutes of audio > > > you are unlikely to have problems either way). You can set the location > > > display to be in samples using an item about half-way down the "View" > > > menu. > > > The zoom buttons are then your friend. > > > > > > > Also, when playing back the video in the compositor, I hear no evidence > > > > of a sync problem. I can turn on both cam and externally recorded > > > > stereo tracks and listen the whole way through the four minute recording > > > > without any reverb or noticeable sync issues. However, after rendering > > > > the files to a final format, I get inconsistent results in xine and > > > > mplayer. > > > > > > This seems rather strange. If there's a sync problem you should hear it > > > in > > > cinelerra unless for some odd reason the tracks aren't always being > > > mixed. > > > I must admit that I do *all* my audio mixing in ardour (I export the > > > camera > > > audio to WAV, import that to ardour and then sync off that), so have no > > > experience doing multitrack audio mixes in cinelerra. > > > > > > > sync.mov: Xine shows sync problems, mplayer no problems > > > > sync.mpg: Xine shows no sync problems, mplayer shows problems > > > > > > That sounds bizarre. While you can get sync problems in certain > > > situations > > > with different AV container formats this would cause the entire audio > > > track > > > to drift out of sync. As I understand it from your opening statements, > > > "sync problem" here refers to an audible echo indicating one source track > > > being out of sync with the other. > > > > > > Regards > > > jonathan > > > > > > _______________________________________________ > > > Cinelerra mailing list > > > [email protected] > > > https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
