Problem joining/playing avi's with ac3 audio

[DaDe]

Hi everyone,

I've been having problems joining/playing avi files with ac3 audio since yesterday. I don't know what happened cause before yesterday everithing worked just fine.
I can join the files without problem, the thing is when i let the file run normally the joined avi makes a strange sound right on the union point and the volume of the second half lowers to an unaudible level. But if i play the avi just after the union point the sound level is normal...
So the volume lowers only when i pass thru the union point, if i skip the union point the audio volume is fine

I have tried different movies and all do the same... since yesterday... i played each part separately and there's no click at the end of the first nor at the begining of the second. The audio is not out of sync either.

Some codec got damaged? Bad luck, and all the files i tried yesterday are somehow wrong encoded?

Any help would be appreciated.

[Baldrick]

how do you join??? which tool?

[DaDe]

I am using Virtualdub Mod 1.5.10.2. The regular open avi, append segment, direct stream copy, save as file method.

[pijetro]

Save the .AC3 out to an uncompressed .WAV..
Reintroduce the .WAV into the original .AVI stream..

Give this a try...Depending on the output, you'll probably need to reencode the .WAV back to .AC3...

This is just a guess though...

[DaDe]

If i do that, will i keep the 5.1 channels?

Thanks!

[mikiem]

"If i do that, will i keep the 5.1 channels?"

I think Yes, a different type of wav file can hold 5.1, but you might have problems if the file size get's too big -- wav is not like avi without size limits. Might wind up joining one mono track and matching others to it in Audacity, then converting 6 mono to ac3. Either way be careful that audio and video lengths match.

There may well be ways of joining the ac3's I'm unaware of, and might even be able to get Nero to do it, though I might toss the rendered video.

[DaDe]

Well, thanks for your help!

I think i found the problem, apparently the ac3 header of the second avi was invalid, at least DVD-lab Pro said so when i load it in the assets... so i let it correct it... mux the ac3 files together, and then replaced the ac3 track with the corrected one and voila! everything is perfect.

Also, almost simultaneously found the program ac3fix wich i think rewrites the headers of the ac3 files, so it makes them right too. I ran some tests with dvd-lab pro and with ac3fix and both programs gave me the results i wanted.

Gracias,
Saluddos!