wav to ac3 is out of sync.

[nick101181]

I captured a tv show using the mjpeg codec. Then I converted the video to mpeg2, then the wav to ac3. I muxed them and all seemed fine at first, but later in the file after fast forwarding it starts getting out of sync. Can anyone help me fix this? The wav file I saved from vdub was the one after I edited commercials and made all the changes I want, so I don't see why it's not in sync.

[dcsos]

How much out of sync?
You hint that its a progressive problem..please clarify (in sync at head, out at middle , worse at end?)
What were the characteristics of the file you processed (frame rate , etc.)?
What programs did you use to make the AC3 conversion?

The only thing I can tell you from the exxtremely limited information you've presented:

These kind of problems often result when one program is based on 29.97 frame rate and the other is 30...

[nick101181]

Well It seems fine in the beginning then ok in the middle then starts going off about 2 seconds I would say near the last quarter of the video file. I converted the audio to ac3 using besweet.

[dcsos]

well check your frame rates carefully and
if you have access to VEGAS 4.0 try syncing with the AC3 in that program BE SWEET is odd and I've never had any good results with it..
Others use it fine..does it have a way to try 30fps instead of 29.97?

[FulciLives]

This sounds more like a capture problem than a WAV to AC-3 encoding problem.

Did you check the original capture to make sure that it was in sync? My guess is original capture is out of sync and is the fault as opposed to the WAV to AC-3 encoding step.

- John "FulciLives" Coleman

[nick101181]

Well I checked and the original capture is alright with the audio. I frameserved the video to tmpgenc to make the m2v file but I had some filters like temporal smoother ,noise reduction,delogo,etc. do you think this had something to do with it? I noticed this 352x480 mpeg2 came out blocky with jagged edges when I tested it out on my dvd player, I have no idea why. It was encoded as interlaced and field order B. I used constant quality with a max of 5000 kbps and a min of 2500 kbps. I captured the avi with mjpeg at 18 setting.

[FulciLives]

Well I checked and the original capture is alright with the audio. I frameserved the video to tmpgenc to make the m2v file but I had some filters like temporal smoother ,noise reduction,delogo,etc. do you think this had something to do with it? I noticed this 352x480 mpeg2 came out blocky with jagged edges when I tested it out on my dvd player, I have no idea why. It was encoded as interlaced and field order B. I used constant quality with a max of 5000 kbps and a min of 2500 kbps. I captured the avi with mjpeg at 18 setting.

Well sometimes using a temporal smoother can throw off the audio sync. Since you still have the original capture why don't you just strip the audio out of it (using VirtualDub) and then encode that to AC-3

Also I've found that Half D1 (352x480) hits the MAX bitrate at 5000kbps meaning that setting the bitrate higher will not increase quality. If your video will fit on a DVD using a CBR of 5000kbps then try that. If you need to use a lower bitrate to make it fit then use a true 2-pass VBR with a MAX of 5000kbps and a MIN of either 1500kpbs to 2000kbps based on what your AVG ends up being (if it is 3500kbps or higher than use 2000kbps as the MIN otherwise try 1500kbps).

Also it is possible to over process the video with filters. I've found that Convolution3D (an AviSynth filter) usually works fine by itself as far as noise and smoothing out the image.

- John "FulciLives" Coleman