Divx audio sync prob

[Jim diGriz]

I've used the Divx creation guide for Movie Park on the Entware site, as well as the one on GP32Emu.The files play fine, except that in many instances, they lose audio sync at some point in the movie and stay in error until the end.The files show the same error when playing them on the PC.All the files have a resultant framerate of under 10 after using the decimate by 3 option.
What I currently do is save off the portion of the movie that is without error using Vdub.I then use the audio interleaving feature in Vdub to correct the second part of the film and then save this off.I just wondered if anyone else had been having similar problems and if they had come up with an easier fix?

 

[Cpt_Kirks]

How much horsepower does your PC have? Are you trying to run any other programs while Virtual Dub is processing?

 

[Jim diGriz]

I'm using an Athlon XP2800 with 512MB memory on a clean install of Win2K.Its been fine for regular Divx encoding and viewing.

 

[Cpt_Kirks]

Can I call you "Slippery"?

Have you tried the files in question using other Divx settings? Do you get the same results?

 

[Jim diGriz]

Sure.Slippery Jim is a fine nick.Just don't let Angelina hear you using it-she hates it and gets a bit psychotic about it

Re-encoding the files for PC use doesn't give any audio errors.Only happens when I use the settings for the GP32.Doesn't happen all the time and it can happen when using a file that has either CBR or VBR audio.I've tried dumping the audio stream as a .wav file and running it through Vdub again.No dice.
Well its not the end of the world.It doesn't happen all the time and when it does I have a fix-just wish it wasn't such a pain to do.
Doesn't look like anyone else has noticed a problem so not to worry.Just thought I'd try and see if an easy fix existed.Just being lazy I guess

 

[nufu]

the best thing to do is: (use virtualdub)

29.97clip ->change the frame rate to 30, then decimate by 3
25clip->decimate by 2

doing it this way should keep sync loss to a minimum, and if your using moviepark, just pause it and start it again to resync

 

[Jim diGriz]

Thanks nufu.I haven't tried those settings and I've tended not to pause often in Movie Park.I will give the settings a try later tonight.

 

[Rico]

Just to build on what nufu said, MoviePark requires a framerate of 10 fps, any higher and you will lose audio sync. That's why 'decimating' 30 by 3 works.

 

[Jim diGriz]

From the very start I've been creating files that are under 10 fps.For 23.976,25.00 and 29.97 fps movies I've been using the decimate by 3 option.The audio sync error has been showing whilst viewing the files created for the GP32 in this way on the PC too.Like I say its a strange one.It only happens with certain movies.Quite a few are ok.

 

[FarmerCuckoo]

Maybe there are some glitches/error in the Divx you're using as the source and they get re-encoded into your Divx for the GP32. Most players for the PC ignore those errors and keep playing, but Moviepark probably doesn't and chokes on it. In this case: audio desync. Try what Nufu said: pausing or try ripping the DVD again (or download another Divx).

 

[Jim diGriz]

That's a good point FarmerCuckoo.I'll run a complete check on the integrity of the files to make sure.

 

[Jim diGriz]

I've been roughing out another fix for the audio sync problems I've been having.It still involves a bit of messing around in Vdub, but it's far easier than trying to sync the audio manually-I know this to be true...sick of looking at the same clip over and over again in Vdub

You'll have to start from scratch with the original Divx file.
Load the original Divx into Vdub.

Select half of the file-using the set start/end from the edit menu.Doesn't have be exactly half-just move around at the general halfway point using the keyframe keys till you find a good spot to make the break.
Now save it off using the regular GP32 settings.
Quit Vdub.
Restart Vdub.
Load in the original Divx again.Now select the half you have already done and delete it.Now save the final half with the regular GP32 settings.
It can sometimes take a while for Vdub to begin saving off the file in this final step.

Generally this will sort out the desync problem.If its still off, then you can try altering Audio Interleaving.

Select Audio>Interleaving.Under the 'Audio Skew Correction' heading, is the 'Delay Audio Track by' box.First try changing the figure in this box to '-500'.Preview the film to see if this has corrected the problem.If not, try changing the setting to '500'.If its still out, I'm out of ideas sorry.

One other major point: sometimes MoviePark will refuse to play the avi that you have split off containing the second half of the movie.I'm still trying to work out what the problem is.It doesn't happen all the time, but it must be mentioned.

Hope this helps somebody else out.