NTSC DVD rip loses sync

[Radixmind]

hi there you guys,

i'm not sure if i'm in the right place for this one. is it DVD ripping, or re-encoding, or what? feel free to move me if i'm in the wrong place.

i've spent the last hour searching this site for any help on this, but nothing i've found seems to answer my problem. although i did find out some stuff i didnt know, so it wasnt, and never is, time wasted!

my problem is: i finally got round to trying to 'fix' a DVD i bought some years ago. i have the 'Rex the Runt' 2 disc DVD pack, region one (NTSC) - another great british show not actually available to us brits, so we have to buy US copies. problem is, the soundtrack on the second disc is switched - left is right and right is left!!! i've tried it on a half dozen players and my computer, it's definitely the disc soundtrack that's at fault. so i decided to rip the disc and correct the audio. simple, yes?

here's what i did. rip the disc to the HDD. use Vobedit to demux the video and audio files. audio is 2-channel AC3 so i convert it to a WAV using Goldwave. swap the channels over, then turn that WAV back into an AC3 using FFMPEGGUI. so far so good? well, nope. nothing i try can get these two files back together again without appalling loss of audio sync.

i've tried building a dvd structure in IFOedit, and in DVDauthorGUI. the discs exhibit gradual loss of audio sync until by 2 hours in, the audio is out by about 10 seconds. i put the files into cuttermaran to see if i could chop it into individual episodes and got audio sync on the preview that was about 10 times worse; it starts out OK but by the end it's almost five minutes out of sync!!! what gives?

just as a test, i redid my experiments using the original AC3 file, and it was the same; nothing would stay in sync. i have no idea why. the original DVD played fine (transposed audio, but in sync), so why wont these unadjusted files go back together?

as a final test, i put everything into my pro authoring software, Adobe Encore. both audio files went in fine, but the mpeg froze the software when i tried importing it. perhaps there's something wrong with my video file?

(by the way, in all areas where the software gave me the option, i selected an NTSC dvd, as the file is NTSC.)

so, is there anyone out there who might know what's going on? i can't believe that these files wont go back together as easily as they came apart. help me please! many thanks.

[mikiem]

perhaps use another de-muxer? PgcDemux works well. Might also use DGIndex -- not it's primary function, but it has a couple of audio tweaks that might save you time, and it goes further then most when it comes to pulldown flags & such, and will tell you exactly what you're dealing with originally. From the sounds of it, might be one of your prob. as the lengths of the audio is probably shorter then the vid.

[Radixmind]

i know it's been a while, but i just managed to get some kind of success for this problem. (thanks to mikiem for his response, by the way.)

i tried a bunch of different demuxing options, including Decrypter, and PGCdemux too, but i was still getting the same audio sync issues. basically, anything i put the files in would completely fail to keep sync whilst i viewed the result. i was hoping to cut the full file into individual episodes (it's 13 10-minute cartoons) but couldnt get cuttermaran to play the files properly.

in the end i used decrypter to demux as chapters, giving me a M2V and an AC3 per episode. i reprocessed the audio seperately, then stuck them together 'blind' in DVDauthorGUI set up for NTSC projects. and it worked! once the files were remuxed into vobs they synced up again!

i still dont know what really was going on here, though. is it the playback codecs i was using? i ended up trying the whole thing on 2 different computers, and got the same probs. perhaps it's got something to do with Windows Media Player Runtime Codec?

as an aside, the reason i was doing this was to correct a fault on the original disc, where the stereo mix was reversed. i though this was pretty bad for a commercial release DVD, but it turned out that it was worse. only the first 7 eps were reversed stereo. the remaining 6 eps were in MONO, for god's sake, and not even a cleanly balanced mono, but a heavily right channel biased mono!

who are these ASSES who make money producing such poor product? we should stone their houses and cars, if only we knew who they were. i find it difficult to believe such roughshod work could pass quality control.