AC3 audio sync

[MaximRecoil]

I don't know what is up with this particular movie but no matter what I do I can not get the audio sync'd. I tried a regular 1 pass CBR for video and MP3 for the audio last night and the audio was off. I tried changing the framerate so the durations matched in VDMod but that just corrected the audio sync near the end but it was off in the beginning. I also tried delaying the audio in the audio skew part of VDMod by 500 ms and that corrected the audio in the beginning of the movie but it was off again near the middle and end.

So, delaying the audio doesn't help, matching the framerate to the audio doesn't help, what else can be done?

At this point I have re-encoded the VOB's to fit on 2 cd's (1250 MB plus 150 mb 2 ch. 192 kbps AC3) and I have the avi video file and the AC3 file seperately. Muxing them with default options in VDMod resulted in out of sync audio just like with the MP3 AVI that I encoded all at once last night.

Any ideas?

[MaximRecoil]

Here is some information in case it is helpful. This is the stream report for the original VOB in VDMod:

Input files :
- [E:\DVD\YG\VTS01-PGC01.VOB]

---== Video stream ==---
Source : [Input MPEG file]
Description : MPEG video stream
Length : 01:46:39.101

---== Other stream ==---
Source : [Input MPEG file]
Description : MPEG audio stream (AC3)
Length : 01:46:38.336

This is the stream report for the Xvid AVI file after being muxed with the AC3 audio with default settings in VDMod:

Input files :
- [E:\DVD\YG\YG audio test.avi]

---== Video stream ==---
Source : [Input AVI file]
Description : AVI video stream
Length : 01:46:39.101

---== Other stream ==---
Source : [Input AVI file]
Description : AVI audio stream 1 [tag 0x2000, ATSC/A-52 (Dolby AC3)]
Length : 01:46:38.336

This is the file information for the original VOB file in VDMod:



This is the file information for the Xvid AVI file after being muxed with the AC3 audio with default settings in VDMod:



BTW, the mouth movement precedes the audio in the beginning of the movie, gets in sync near the middle and then the audio starts to precede the mouth movement toward the end. WTF?

Is there even a way to fix that short of splitting the file up into 4 or 5 sections, sync'ing the audio in all of them and then rejoining the files? Why is it like that in the first place? You can see that the AVI video has the same number of frames, frame rate and duration as the original VOB video and of course the audio is identical to the stream in the original VOB since that is where I got it from in the first place...

[UncasMS]

does the running time of your ac3 differ from that of your video?

[MaximRecoil]

Originally posted by UncasMS
does the running time of your ac3 differ from that of your video?

Yes it does slightly but it is the same way in the actual VOB file also (which is in perfect sync). 01:46:39.101 for the video and 01:46:38.336 for the audio (see my above screenshots and reports for both the original VOB and the AVI+AC3).

The strange thing is the fluctuation of it. The audio starts out early; gets in sync toward the middle of the file and then lags behind by the end of the file. It is as if the audio was stretched from both ends and squeezed in the middle. Very strange.

[UncasMS]

ok, the ac3 wont be to blame

which interleaving settings did you use and which version of vdMOD?

[MaximRecoil]

I have tried default which is 500 ms preroll and interleave once every frame. I have tried 96 ms preroll and interleave once every 96 ms and I have tried 160 ms preroll and interleave once every 160 ms. I have tried all of these with various audio delay settings such as default (0 ms), -67 ms which is what Smartripper claimed that my A/V delay was in the VOB and -500 ms. I got different results every time but always that weird variable audio sync.

I am using VDMod 1.5.10.1 build 2366.