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alwayslearning
Audio / Video Sync and Impression
on Jan 14, 2003 at 5:21:20 am

I have a .avi file created in Premiere 6.5. I used the Adobe encoder to create a MPEG-2 file.
I imported the file and the .wav file into Impression (Pinnacle).
On the timeline in Premiere, I have the audio (music) start about 2 seconds before the video. I brought the mpeg2 file into DVDit LE and it played correctly, but I discovered that with LE I can't make chapters and buttons. I am just learning that.... or trying to. I started several months ago, but it all got put on the back burner due to life happening and now I am starting from scratch with DVD authoring. I remembered that I had Impression on my machine, so I opened that and imported my mpeg2 file into that. I can see how to do buttons (sort of :) ) in Impression, but when I play the video, it starts about 1-2 seconds before the audio.
Any thoughts on why this would be?
Thanks, AlwaysLearning


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alwayslearning
Thought this would fix it...... but......
on Jan 15, 2003 at 6:20:01 pm

I had a thought last night about my audio/video sync dilema.
I placed a 2 second clip of black in front of the video on the Premiere timeline. The leading edge of the black clip lined up with the start of the audio. I exported the "new" .avi file to mpeg, imported the new mpeg file into Impression, went to the start of the movie and clicked on play. Again, the video starts a second or so BEFORE the audio. It is supposed to be the other way around and indeed is, in Premiere.

What gives?

AlwaysLearning


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WTS
Re: Thought this would fix it...... but......
by
on Jan 17, 2003 at 12:59:08 am

I would check to see if the timecode duration of your video and audio match, and it they do, then they should be in-sync when you create your disc. Software emulation of the video and audio can appear to be out of sync from within the authoring application itself, but that is a limitation of these types of interfaces, and not a true relfection of the final product. The emulation interface is for testing your button linking, and setting chapter marks, and not to see if the audio and video are in sync. Don't insert blank video clips to try to 'line-up' your audio and video, you'll only frustrate yourself.

Jim


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alwayslearning
Re: Thought this would fix it...... but......
on Jan 17, 2003 at 4:16:39 am

Thanks WTS. I'll get rid of the black and see what happens with the burned DVD.
I don't know if you saw my other post concerning Impression SE and it's limitation about chapters, but could you take a glance at the post and maybe you'll have a thought on that?

Thanks, AlwaysLearning


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AD3
Re: Thought this would fix it...... but......
by
on Feb 14, 2003 at 6:47:00 am

Have had a similar problem with Impression and burned to DVD-RW to check. Sure enough, the audio sync issue was there. From my experimentation this only happens when I use an compressed AC3 audio stream with a VBR MPEG2 video file. If I use a CBR video stream, no prob. Let me know if you have more luck than I do.


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pjpfuchs
Re: Thought this would fix it...... but......
on Feb 18, 2003 at 7:20:17 pm

Many others have screamed about video/audio sync problems and I'm one of them. I acquire from an analog Hi8 camcorder (using a Pinnacle Pro-ONE RTDV card). The result is an .avi file in Premiere. I consistently get a sync problem in the sense that audio is about 0.3% slower than video.

The beginning of my avi files is always perfectly in sync (so it looks like your problem is different than mine).

If I acquire a 3 to 5 minutes file, the sync at the end of the file is good enough most of the time. Do the math: 0.3% of 5 minutes = 0.9 second. Though in some cases, 0.9 second already looks ugly (call me a perfectionnist if you will).

Of course, if I acquire a 20 minutes file, the sound at the end of the movie comes 3.6 seconds later than the image, no comment

I have tried in Premiere to "un-link" video and audio and then makes audio running a bit faster. The issue is that Premiere will not give you enough granularity. Either you play at 100% of speed, or 101% which is too fast. You can't set the speed of the audio clip at 100.3%.

The solution: when acquiring, limit to 3 minutes. It's a lengthy, boring process, but you'll get good results.

Or if you have even a 1 hour avi file, cut it into 20 clips of 3 minutes each (approx., wherever it makes sense to cut) and then shift the audio in each clip to have a perfect sync let's say in the middle of the clip. So you will be out of sync by at worst 300 milliseconds at the beginning and at the end of the clip. That's usually acceptable even if you have shot let's say a close-up of a singer!

If somebody has got a better work-around, I'm VERY interested!

JP


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