AVI to Mpeg2 Sync Problem

NaperRick wrote on 11/9/2003, 11:22 PM

I recorded a show off tv using my ATI AIW tuner. The file created was an AVI. When I brought it into MS3 it has the following properties:
Video: 640x480x16, 29.970 fps, 00:29:59;01 (progressive) no compression
Audio: 44,100 Hz, 16-bit, Stereo, 00:29:58;18
I can play the AVI files in several different players, including WMP9 and it plays fine (audio and video in sync).
When I play it in MS3 preview the audio is out of sync. When I create a Mpeg2 in MS3 the resulting mpg file has the audio out of sync when played in various players also.
Is there something I need to do or is there something about the AVI file that isn't quite right?

Comments

NaperRick wrote on 11/9/2003, 11:38 PM

I did another test with a short file and I noticed that in both cases the length of the video stream is slightly longer than the length of the audio stream. So I went in MS3 and zoomed in on the end of both tracks and moved the audio track so it ends at the same time that the video track ends - when I did that the audio was in sync with the video.
That fixes the problem but I'm confused as to why I should have to do it (shift the audio).

discdude wrote on 11/10/2003, 8:07 AM

This is a common problem with low-end capture devices. The AIW relies on a soundcard in order to capture sound. The sync problems arise because you are using two different devices with different clocks.

As you noticed, you can compansate for these differences through software. Often times this can be done automatically by the capture program. Neither the ATI MMC (Multimedia Center) nor Vidcap support this functionality however.

Walleye2 wrote on 11/10/2003, 12:45 PM

Any idea why the files play OK in other players but not in MS3?

discdude wrote on 11/10/2003, 4:46 PM

No idea why media players can play files in sync while MS3 fails. I can only speculate that media players can compensate for slightly out of sync videos.