Audio out of sync, Batch DVD Steam Converter & Muxman

[assman24]

I am trying to convert some m2t files that I firewired from my Canon HV30 into DVD. The m2t files play perfectly, the audio and video line up great. I am using Batch DVD Streams Converter to get the m2t files to DVD. It outputs an AC3 file and an m2v file. I use Muxman DVD Authoring that comes with the Batch DVD Streams Converter program to mux those 2 files into a DVD VIDEO_TS folder. And finally I use Image Tool to turn those into an ISO image.

The audio on the VOB files/ISO image is out of sync with the video. It starts out in sync and gets progressively worse (sound is before the video). This happens on 2 out of the 4 m2t files that I'm converting. I've tried remuxing several times, and I even tried reconverting from m2t to m2v and AC3. Each time I got the exact same results(same file size even).

I can't figure out why these 2 are out of sync. FWIW the settings in the Batch DVD Streams Converter are all the defaults, set to highest setting. I had to click 'Change Source Aspect Ratio' Source 16:9 Target 16:9 because the first time when it was unchecked it changed it from 16:9 to 4:3 for some reason.

Anyway, does anyone have any ideas of why it is doing this? I would rather not use the delay function when muxing b/c I don't really think that will be very effective.

Thanks,
Adam

[Delta2]

The way you can fix that problem is to speed up a little bit the audio to match the video, i.e, re-clock your audio

take your AC3 file and use AVISynth this way :

LoadPlugin("NicAudio.dll")
MyVideo = Blackness().assumefps(25)
MyAudio = NicAC3Source("audio.ac3").TimeStretch(tempo = (100 * 25.005) / 25)
AudioDub(MyVideo, MyAudio)

That example will speed up a little bit the audio, 2 seconds +/-, for a 25 FPS original source ( I used 25.005 )

if Audio is before Video at the end of the file, then you must increase FPS
if Audio is after Video at the end of the file, then you must decrease FPS

Then use Besweet or Aften or VirtualDub to get your new AC3 with new timings, and use Muxman to re author

This needs patience and a lot of trials, you should begin with small values

[assman24]

Thanks for your help Delta.

Will AVISynth progressively speed up the audio? There is no delay at the begging of the VOB, but it gets increasingly out of sync as the video plays on.

Also, what is the reason some of these turn out okay and some do not? I still have the original M2T files, so I can still try something else to get a better outcome if anyone has any other ideas.

[Delta2]

Thanks for your help Delta.

Will AVISynth progressively speed up the audio? There is no delay at the begging of the VOB, but it gets increasingly out of sync as the video plays on.

Yes it does

Applying a delay affects the audio stream in a constant way - when it is a constant desync from begin to end

But your problem is different, it is a progressive desync , therefore you must speed up or slow down audio playback. That could be done also with adjusting Audio Sampling Rate (Re-Clocking), but this method is not so complicated and does the same

Let the video stream as it is, an see what framerate it has, then adjust audio as I said making small changes

You must do some trials until you reach the best results

VSO ConvertXtDVD just speeds up audio or slows down if it detects that a audio source will not match video playback time during conversion, and it occurs mostly with MP3 VBR

maybe someone have a better idea