audo video sync issues merging two titles

[supernater]

Hi

I'm trying to compress my copy of the Lord of the Rings Fellowship of the Ring Extended Edition into a single .mkv file. This is a challenge because the movies is contained on two disks. I've tried a variety of methods to join these two disks together but every method I use created audio/video syncronization issues. Here is what I've done so far.

Attempt #1 Plain old file rename and dgindex

I simply took the sever VOB files from disk #2 (VOBs were named VTS_01_01 to VTS_01_07 but I renamed them to VTS_01_08 to VTS_01_14 ) and put them in a folder with the VOB files from disk #1 (VOBs were named VTS_01_01 to VTS_01_07 ). I used dgindex to demux and make the .d2v file and compressed with MeGUI. The result was that the disk#1 part of the compressed video was fine but the disk #2 part of the compressed video file was WAY out of sync (audio was playing way before the characters lips were moving).


Attempt #2 DVDshrink reauthor

I used DVDshrink in reauthor mode to combine the two disks into one disk. After this was done I realize that all DVDshrink did was put two separate titles onto one disk. I didn't think this result would be much better than my previous attempt (it wasn't) but I gave it a go anyway. I used dgindex to demux and make the .d2v file from the files that DVDshrink created and compressed them with MeGUI. The result was the same as my first attempt.


Attempt #3 DVD2one seamless join

I have a copy of DVD2one so I used the "seamless join" option to merge the two titles into one. I dgindexed it and compressed. This time the result was noticably better, but the audio still wasn't synced with the video.


Attempt #4 VOBedit Merged

I renamed the seven VOB files from disk #2 to VTS_01_008 to VTS_01_014 and renamed the seven VOB files from disk #1 to VTS_01_001 to VTS_01_007 and used VOBedit to merge them. I dgindexed it and compressed. The result was the best yet (a little better than attempt #3) but the audio in the disk #2 part of the compressed video was still out of sync.


I'm not sure where to go from here. VOBedit seems to work the best so far. Can anyone give me any ideas of what I should try next? Are there any other recommended tools? Thanks.

[setarip_old]

Hi!

In conjunction with your "Attempt #4, BEFORE renaming and joining the second disc's .VOBs to those of the first disc, try using "DelayCut" (by "jsoto") as needed on the second disc's .VOBs.

You can get "DelayCut" at:

http://jsoto.posunplugged.com/audiotools.htm

[Ghitulescu]

I have myself LotR. The movie it's on the first DVD, the extras (collec., deluxe etc. editions) are on the second.

Just rerip your original from DVD1 in one file with your favourite ripper then feed this file to your favourite MKV program.

[r0lZ]

The problem is probably caused by the presence of cells without sound at the beginning of the second part or at the end of the first. You can try to remove them with PgcEdit, or retry your attempt #2 but cut the part without sound with DVDShrink.

To verify the exact length of the audio stream, you can demux it with PgcDemux (http://jsoto.posunplugged.com/dvdtools.htm).

You can also use commercial tools such as Womble MPEG Video Wizard DVD to join the two parts, without sync issues (as it rebuilds the missing audio or video parts automatically.)

There is a live thread about a similar problem here (http://forum.digital-digest.com/showthread.php?t=91507).

[supernater]

I have myself LotR. The movie it's on the first DVD, the extras (collec., deluxe etc. editions) are on the second.

Just rerip your original from DVD1 in one file with your favourite ripper then feed this file to your favourite MKV program.

Ah, I should have mentioned that this is the LOTR extended edition, so there are four disks total, the movie is one the first two disks and the special features are on disk #3 and disk #4. I will add that info to my original post.

Hi!

In conjunction with your "Attempt #4, BEFORE renaming and joining the second disc's .VOBs to those of the first disc, try using "DelayCut" (by "jsoto") as needed on the second disc's .VOBs.

You can get "DelayCut" at:

http://jsoto.posunplugged.com/audiotools.htm


The problem is probably caused by the presence of cells without sound at the beginning of the second part or at the end of the first. You can try to remove them with PgcEdit, or retry your attempt #2 but cut the part without sound with DVDShrink.

To verify the exact length of the audio stream, you can demux it with PgcDemux (http://jsoto.posunplugged.com/dvdtools.htm).

You can also use commercial tools such as Womble MPEG Video Wizard DVD to join the two parts, without sync issues (as it rebuilds the missing audio or video parts automatically.)

There is a live thread about a similar problem here (http://forum.digital-digest.com/showthread.php?t=91507).

Thanks for the suggestions guys. I'll try that and report the results back to you.

[supernater]

I fixed the problem. The first thing I did was demux Disk #1 on it's own using dgindex. I made an avisynth script and opened it in VirtualDubMod and obtained the length of the video from Disk #1. I opened the audio from Disk #1 in delaycut and found the length and delay of the audio. The duration of the audio and video from Disk #1 were...

Disk#1
Video 1:45:36.580
Audio 1:45:36.160 (DELAY 0ms)

Since there was no delay I was able to determine the length of the audio was 420ms less than the length of the video so I decided to introduce 420 ms of silence into the audio.

I merged the VOB of the two disks using VOBmerge. I demuxed the merged VOB using dgindex. I converted the AC3 audio file (which is now a combination of the audio tracks from both disks) into a .wav file and opened it in Audacity. I found the point in the audio track where the two disks were merged and introduced 420ms of silence at this point. I exported this as a .wav and compressed it and then compressed the video and muxed them. The result is perfect. No delay whatsoever.

[r0lZ]

Nice! However, with your method, you have been forced to re-encode the audio, introducing a slight quality loss. By using DelayCut on the original demuxed AC3 track, you could have archived the same result without re-encoding the audio. (Same thing with the payware Womble.)

Note also that you should not need an avisynth script to open the VOB or the MPV in the latest VirtualDub (v1.8.8). VirtualDubMod is now outdated (9.6.2003!)

[supernater]

Nice! However, with your method, you have been forced to re-encode the audio, introducing a slight quality loss. By using DelayCut on the original demuxed AC3 track, you could have archived the same result without re-encoding the audio. (Same thing with the payware Womble.)

Note also that you should not need an avisynth script to open the VOB or the MPV in the latest VirtualDub (v1.8.8). VirtualDubMod is now outdated (9.6.2003!)

Does converting AC3 to wav decrease the quality? I thought wav was a lossless format.

Thanks for the info on VirtualDub, I've been using VirtualDubMod for a while now. I'll give VirtualDub 1.8.8 a go.

[r0lZ]

I exported this as a .wav and compressed it and then compressed the video and muxed them.WAV is lossless, yes, but you have re-compressed the audio, right? The re-compression (to AC3 or MPEG) is the cause of the quality loss.

BTW, I realize now that you have also re-compressed the video stream. It's also an unnecessary lossy step (unless you need to compress the DVD anyway to put it on a DVD-5.) You should try to use the original streams whenever possible.

[supernater]

WAV is lossless, yes, but you have re-compressed the audio, right? The re-compression (to AC3 or MPEG) is the cause of the quality loss.

BTW, I realize now that you have also re-compressed the video stream. It's also an unnecessary lossy step (unless you need to compress the DVD anyway to put it on a DVD-5.) You should try to use the original streams whenever possible.

Ah, I see what you are saying. Yes, in that case, you are correct. However, I'm not recompressing to AC3. I should clarify... My goal is to compress this into a x264 video with AAC sound, not AC3. In my case, the audio and video were processed as follows...

Audio:
AC3 -> WAV -> Nero AAC

Video:
Original VOBs -> Combine using VOBedit -> MeGUI x264 encode.

So, in my case, going from AC3 to WAV to AAC is the same loss in quality as going from AC3 directly to AAC, right? Please correct me if I am wrong (I very well could be, I am learning this as I go).:D

But, I see your point, if I were simply trying to reauthor the DVD then, yes, using my method and recompressing to AC3 sound would introduce a slight loss of quality for the both the audio and video.

[r0lZ]

OK, I didn't know that you were transcoding to another format. You are absolutely right.