Problem merging .ac3 files

[m1a2lt]

Recently tried to combine two .ac3 files from a two sided movie and, although the .m2v file worked fine, there is a problem with the join in the .ac3 file. Used FileMerger to combine and both SpruceUp and IfoEdit reject the combined file when it hits 50%. I burned the movie and everything is fine until halfway through when the audio quits although the video continues. Any ideas what is wrong?

[slig]

it seems to me that you have a broken ac3 header. so, before you combine two ac3's, open each one in the program HeadAC3he. In the source field indicate the path to your ac3 file. In the target field indicate source. It doesn't re-encode ac3, it just quickly rewrites header. You can also try to use this program after you combine. Reply, if your experience is successful.

[jankster]

This is how I do it.

Open both ac3 files in "Ac3 Delay Corrector" If there are any errors try to resave it with 0-ms delay. This fixes some problems.

If there are bad inner frames use "ac3cutframes.exe".

I've also had bad headers that can only be fixed by a "hex editor". To fix a corrupt AC3 stream header use a hex editor and find the first good “OB 77” sequence. Delete back to the start of the file from this point.

You most likely will have a "audio/video" sync problem with the 2nd part. Measure the exact time of 1.ac3 + 1.m2v. The m2v will be a little longer, so add this amount as a delay to your 2.ac3 file.

Finally use this simple DOS command to merge your ac3 files "copy /b file1.ac3 + file2.ac3 output.ac3".

WORKS GOOD.

[m1a2lt]

Used HeadAC3he on the two seperate .ac3 files, File Merged them and tried them out in SpruceUp and, in simulation, had no problems. The unusual thing about this disk (Bridge on the River Kwai) is that it is like a two sided disk, although both streams are on the same side. It had no delay, so no problem. I will be burning later today and will give it a run through on an actual player and will let you know how it works. Thanks, Slig.

I'm going to do "Patton" today, so I may have to use your method jankster, since there is a delay on the second .ac3 file.

Something else I ran into: I did Gettysburg and one side offers 6 channel but the other side does not. Can you combine two .ac3 files that have different numbers of channels or will this cause more problems than it is worth?

[m1a2lt]

Had no problems; plays well in the DVD player. Thanks for your help (now the real test: putting both DVDs together for "The Godfather 2"!)