Change video, keep audio without re-encode ? Problems with strange AC3.....

[Gwar]

Hello guys,

I have another project going on for several days now and I can't seem to get it done. Here's what it is...

I received a special fan made dubbed version of a movie from a friend who only had the DVD left and not any project files.
I wanted to change the Video because The Video source was in a low resolution to make it fit on a DVD5. I wanted to take my DVD9 and put the audio on it... So what I did was to extract the DVD's with DVD Decrypter to one file.
Then I just extracted 2 video files with DVDlab pro 2 (demultiplex).

I cut the DVD9 video in 3 pieces with Womble mpeg2vcr and joined the parts together with a bit of extra blackening at the end with Womble MPEG Video Wizard. So the DVD9 video has the same lenghth as the DVD5 video. I checked and compared the DVD5 video and the DVD9 video and everything was the same frame on the same time so it was ready.

Then I added the ac3 audio of the dvd5 and the video of the dvd9 to the project in DVDalb pro2 and compiled it to a DVD.

It doesn't play right it runs too fast and some points and then runs out of synch...
After the demultiplexing in dvdfab I also realized that the video of the dvd5 is actually shorter than it's audio layer... So the lenghth according to DVD-lab PRO looks like this:

DVD5 AC3 01-58-29
DVD5 Video 01-57-00
DVD9 Video 01-57-00

(hours.minutes-seconds)

I thought that this wouldn't be a problem since the regular dvd5 runs fine. But the dvd5 audio with the dvd9 video doesn't run right although it had the same lengh as the video of the dvd5.

So what is going on here? Is the ac3 corrupted because it originally was joined together from 2 sources ?
But why does the original fan made dvd5 run right and my re-authored dvd9 version not??

It's driving me mad so I'm looking for a solution to replace the dvd5 video with the dvd9 and keep the audio of the dvd5 without any problems.

I hope someone knows a solution.

thanks a lot

Gwar

[aedipuss]

different frame rates on the videos?

[Gwar]

different frame rates on the videos?

No everything has the same frame rate. PAL (25fps)

[manono]

No everything has the same frame rate. PAL (25fps)

I checked and compared the DVD5 video and the DVD9 video and everything was the same frame on the same time so it was ready.

If the first is true, then obviously the second isn't. And just why did you feel the need to pad the video with black frames at the end? And the DVD9 video only became the same length as the DVD5 video after you added the black frames? So they're not actually the same length? And why did you first cut and then rejoin the DVD9 video?

[Gwar]

No everything has the same frame rate. PAL (25fps)

I checked and compared the DVD5 video and the DVD9 video and everything was the same frame on the same time so it was ready.

If the first is true, then obviously the second isn't. And just why did you feel the need to pad the video with black frames at the end? And the DVD9 video only became the same length as the DVD5 video after you added the black frames? So they're not actually the same length? And why did you first cut and then rejoin the DVD9 video?

I compared both videos during the cutting progress. I had to cut a bit of black frames at the begining of the DVD9 in order that it starts at the same time as the DVD5. Then I had to cut 1 ms in the middle of the DVD9 because there was one scene where the DVD5 was 1ms shorter than the DVD9. And in the end the DVD5 had some seconds more black frames than the DVD9 so I added those to it.

After that progress and the merging together the dvd5 was exactly the same as the dvd9 from the lenghth.

So for example if I skip to 1-35-20 on the DVD5 video and to 1-35-20 on the DVD9 video it shows the same image on both of them.

[manono]

Then if the 2 videos are the same length and have the same framecount, the audio should match up. There's something wrong with the information you've given us, though. My suggestion is to mux the DVD5 video with the audio using Muxman. If they're in synch, then mux the DVD9 video with the audio and see if they're in synch.

If you're saying there was no problem with the synch of the DVD5 video when on the DVD with the audio, then they should still synch up when remuxed, and either the video length is incorrect or the audio length is incorrect.

[Gwar]

Then if the 2 videos are the same length and have the same framecount, the audio should match up. There's something wrong with the information you've given us, though. My suggestion is to mux the DVD5 video with the audio using Muxman. If they're in synch, then mux the DVD9 video with the audio and see if they're in synch.

If you're saying there was no problem with the synch of the DVD5 video when on the DVD with the audio, then they should still synch up when remuxed, and either the video length is incorrect or the audio length is incorrect.

Okay I'll give muxman a try.

The only strange thing I realized about the dvd5 was that if I play it with vlc or in my stand alone player it runs fine, but if I open it in mpeg2vcr there is no sound in the scenes which were inserted when the audio layer was created.
It looks like there is a compability problem within the ac3 audio track. For example if I open the ac3 or the whole dvd in vlc it plays fine but if I open the video in mpeg2vcr it only plays the parts of audio source 1 and every time a part of audio source 2 appears it plays no sound..

This is weird

[Gwar]

muxman didn't work. The file has audio skip at the parts of the inserted audio and later runs out of synch..

damn -(

[manono]

Hehe, Muxman did work. Maybe there's something wrong with your audio. My next suggestion is to try and demux it with PGCDemux and then check if it's closer in length to the videos than what you showed us before. Then try muxing it with Muxman again.

[Gwar]

Hehe, Muxman did work. Maybe there's something wrong with your audio. My next suggestion is to try and demux it with PGCDemux and then check if it's closer in length to the videos than what you showed us before. Then try muxing it with Muxman again.

alright I try to use that programm instead. I may skip the part with the dvd decrypter also and just try to demux the audio out of the regular dvd5..

I may also use another programm for muxing than dvdlab? I realized that it creates smaller vob files than on usual dvd's...

[manono]

This audio, how was it created or was it edited somewhere along the line? What could lead it to skipping and going out of synch? If it plays OK with the original DVD5, have you done anything to it at all since then, besides just demuxing it?

Anyway, as far as I know DVDLab has a decent muxing engine. If you don't need menus, though, Muxman's is better.

[Gwar]

I'll ask the guy who created the DVD how exactly he treated the audio.

As for myself I didn't do any change to the audio. I decrypted the DVD to one large file (instead of vobs) with DVD decrypter, extracted the audio with DVD lab and that was it.

This audio, how was it created or was it edited somewhere along the line? What could lead it to skipping and going out of synch? If it plays OK with the original DVD5, have you done anything to it at all since then, besides just demuxing it?

Anyway, as far as I know DVDLab has a decent muxing engine. If you don't need menus, though, Muxman's is better.

[Gwar]

I demuxed the audio and video of the DVD5 with PgcDemux and after that I muxed it with muxman. And although those were the files which ran okay on the dvd this time there is the

audio problem and it's running out of synch...

I added the two files in dvd lab to see what the time is and it shows
audio: 01-58-29, video: 01-57-00.

I don't understand this because the audio is in synch and running smooth on the untouched DVD5 version, but when I demux and mux it it fails.

What's going on here?

I hope you can help me manono.

thanks

This audio, how was it created or was it edited somewhere along the line? What could lead it to skipping and going out of synch? If it plays OK with the original DVD5, have you done anything to it at all since then, besides just demuxing it?

Anyway, as far as I know DVDLab has a decent muxing engine. If you don't need menus, though, Muxman's is better.

[manono]

OK, it plays OK on the original DVD but goes heavily out of synch when demuxed. Is there a certain point where it all of a sudden goes out of synch by a minute and a half? If so, can you find that place? Is there something strange about the place where that break occurs?

Next, check if there are two VOB IDs. Open the original DVD in PGCDemux. Rather than the default 'by PGC', tick 'by VOB ID'. Take note in the drop-down box if there are two VOB IDs. If so, I suspect the audio for the first VOB ID stops well before the end of the video (but just in case, do a 'Check A/V Delay' for each VOB ID). Maybe there's a long period of silence, or maybe a long lasting black screen for some reason. If that's the case, demux both VOB IDs separately. If there are two VOB IDs with a big audio break between the two, report back and we'll take it from there.

[Gwar]

It goes out of synch when the first scene starts where the alternatve audio source was taken.
The ac3 audio was cut together from 2 sources.
It's like the following:
Audio Layer 1: Censored, German
Audio Layer 2: Uncensored. English
----> cut together to a new Layer.

So the guy who couldn't remember which programm he used cut both audio layer together to one without losing the 5.1 mix, so I guess without any loss.

So on the DVD it's running synch and fine but after demux:
During the first scene were the English part of the layer runs the audio starts to make "jump" sounds, like drop outs.
After the scene is over and the German audio runs it is running okay but is very heavily out of synch then...

PgcDemux by VOB id shows only one VOBid. When I click on check A/V delays it shows. 0 msecs.

OK, it plays OK on the original DVD but goes heavily out of synch when demuxed. Is there a certain point where it all of a sudden goes out of synch by a minute and a half? If so, can you find that place? Is there something strange about the place where that break occurs?

Next, check if there are two VOB IDs. Open the original DVD in PGCDemux. Rather than the default 'by PGC', tick 'by VOB ID'. Take note in the drop-down box if there are two VOB IDs. If so, I suspect the audio for the first VOB ID stops well before the end of the video (but just in case, do a 'Check A/V Delay' for each VOB ID). Maybe there's a long period of silence, or maybe a long lasting black screen for some reason. If that's the case, demux both VOB IDs separately. If there are two VOB IDs with a big audio break between the two, report back and we'll take it from there.

[manono]

OK, so the guy that made it didn't know what he was doing and created messed up audio. There's only one way to fix it and that's by splitting the audio and cutting out the minute and a half of garbage. Demux it (PGCDemux), split it at the place where it goes out of synch (I use HeadAC3he), fix the delay by cutting out a minute and a half of garbage sounds (DelayCut, or, with some experimenting with where to cut, maybe Headac3he). Remux (Muxman), using the 'Add' button to add back the two pieces of the audio.

[Gwar]

this sounds like a hell lot of work. I think were about 103 cuts in the german part so the english part was inserted at least 80-100 times... There seems to be no programm which shows where the one and a half minute of messed up stuff comes from.

Delay cut shows the following information:

====== INPUT FILE INFO ========================
File is ac3
Bitrate (kbit/s) 384
Act rate (kbit/s) 384.000
File size (bytes) 341259008
Channels mode 3/2: L+C+R+SL+SR
Sampling Frec 48000
Low Frec Effects LFE: Present
Duration 01:58:29.562
Frame length (ms) 32.000000
Frames/second 31.250000
Num of frames 222173
Bytes per Frame 1536.0000
Size % Framesize 1280
CRC present: YES
=============================================
====== TARGET FILE INFO ======================
Start Frame 0
End Frame 222172
Num of Frames 222173
Duration 01:58:29.536
NotFixedDelay 0.0000
=============================================

So I don't know how to cut out something when I don't know where it is, except that I could cut the whole movie apart but then I could have created the audio myself the first plays. i was so happy that I found someone who did it so that I don't need to do it. I mean it is a pain the ass to create a flawless version out of that..

So if there isn't an easy way I gues the last option would be to play the movie in a stand alone player connected to a dvd recorder. Then it should be recorded without any delays. I have to check if there are recorders who have an optical or coaxial in, if not I'll have to use cinch audio which could be a loss..

OK, so the guy that made it didn't know what he was doing and created messed up audio. There's only one way to fix it and that's by splitting the audio and cutting out the minute and a half of garbage. Demux it (PGCDemux), split it at the place where it goes out of synch (I use HeadAC3he), fix the delay by cutting out a minute and a half of garbage sounds (DelayCut, or, with some experimenting with where to cut, maybe Headac3he). Remux (Muxman), using the 'Add' button to add back the two pieces of the audio.

[manono]

I've done this a bunch of times. Figure out when the bad audio begins and make your first cut there using HeadAC3he(or even DelayCut). Play back the ending to make sure it was cut where you wanted. Then make the next cut to create the part 2 about a minute and a half past the first cut (figure it out exactly). Play it to make sure it begins where you want. Write down the times and frame numbers so you'll know when you change the times a bit when you do it the second time. Reauthor with Muxman and test. I doubt you'll get it exactly right the first time, but you should be OK about the third time.

I'm assuming that the 90 seconds or so of extra audio comes all at once, and isn't cumulative over the course of the entire video. If it is, then your idea of recording the sound with a DVD recorder (or on the computer) might be a better one.

[Gwar]

this sounds too crazy for me I think I'll be going mad...

I have a hdmi pci card to record from my HD hdd receiver. I think I just use my standalone DVD Player and capture from it's hdmi output to my hdmi input..

Thanks for all your help manono

cheers