Joining 2 AVI cause loose of synchro

[vio_man]

I have 2 AVI's which I want to join. If I use the Virtualdub's append feature it will give error, says that audio sources are different. I don't see any difference, both are MP3 VBR with the same samplerate. AVI Mux-GUI does joins them, but the 2nd part (corresponding to the 2nd AVI) will loose audio/video synchro.
I already tried demuxing the sound to PCM for both videos, but I got synchro issue when converting to DVD (using Avi2DVD).
I don't know what else to do.

[setarip_old]

Hi!

Try the following:

For EACH of the two files, do the following:

1) Load file into VirtualDub
2) Set "Video" to "Direct Stream Copying"
3) Set "Audio" to "Full Processing Mode"
4) From the "Audio" dropdown menu, select "Compression"
5) Select, for example, 22,050Hz
6) From the "Audio" dropdown menu, select "Conversion"
7) If necessary, put a checkmark next to "Display all formats"
8) Select your preferred sampling rate from amongst the, for example, 22,050Hz .MP3 rates listed
9) Click on "OK"
10) Save with a new filename

By the way, what software and procedures did you use to split your original .AVI, that somehow apparently changed the audio rate?

[manono]

Hi-

I don't know what else to do.

First, don't ever use VDub when VBR MP3 audio is involved. But in the hope that you really meant to say VDubMod, I'll give you a fix. Find out the amount of asynch of that 2nd part. Then, before joining together in AVIMuxGUI, set a delay for the second one equal to the amount it's out of synch after joining. That'll throw the 2nd one out of synch, but when joined with the first one, the whole thing should be back in synch. To find the amount the 2nd part is out of synch, and to adjust the delay in VDUbMod:

Open the joined AVI in Media Player Classic. Right-click the screen and go Options->Filter->Audio Switcher->check the "audio time shift" box, and fill in an estimate of the amount of asynch of the 2nd part. Hit "Apply" and test it out. Negative values are to make the audio play earlier. 1000 ms= 1 second. Resume playback. Adjust until you get it right. At that point you'll know how much the audio is out of synch and how much to set the delay in VDubMod for the original 2nd video. Then open that AVI in VDubMod, set the Video for Direct Stream Copy, go Streams->Stream List->Right-click the audio->Interleaving->Audio Skew Correction, and set the same delay as you found using MPC. OK your way out of there, go File->Save As, give it a new name, and when done join it with the first video and test.

When all done, either uncheck the box or set the audio time shift back to 0 in MPC.

setarip_old-

By the way, what software and procedures did you use to split your original .AVI, that somehow apparently changed the audio rate?

He said the samplerates were identical. Usually the problem stems from different audio bitrates. GSpot can tell him the audio bitrate of the 2 videos. Splitting a larger video with VBR MP3 audio into 2 parts can often give the 2 resulting parts different audio bitrates, and prevent VDubMod from rejoining them. Besides, this is a "Don't ask, don't tell" site, your question smacks of entrapment, and is sleazy if you ask me. Cut it out.

[vio_man]

Thank you manono. Your guide did the trick :)

[vio_man]

But now I got another problem. I was able to synch the 2nd part with a +2000ms skew. But when joining with the 1st part, AVI-Mux GUI screwed the 1st part and it looses syncho, while the 2nd is perfectly synched now.

[manono]

Well, that's just plain weird. Never seen that, although I've never used AViMuxGUI either.

If you're converting to DVD (?), then you can keep them separate and join at the authoring stage. But I know nothing about AVI2DVD or how it works. So, you could just keep them separate, and use the 2nd part that you made out of synch.

Another thing you can try, and maybe a better solution, is to extract the MP3 from each (perhaps as WAV), and convert each to AC3 for the DVD, or to MP2 audio, if that's what you're using. Then you can take the AC3 for the out of synch 2nd part and add silence or cut it (depending on if the audio plays before or after the video) and then join the 2 parts together. You use DelayCut for this. There are several ways to solve the problem, and I've done all this before. But I've never used AVI2DVD.

[setarip_old]

I already tried demuxing the sound to PCM for both videosTry this - For each of the .AVIs do the following:

1) Load file into VirtualDub
2) Set "Video" to "Direct Stream Copying"
3) Set "Audio" to "Direct Stream Copying"
4) From the "Audio" dropdown menu, select ".WAV audio" - and load the appropriate PCM (.WAV)
5) Save .AVI with a new filename

Check to see if each of the new .AVIs are in synch

Close and re-open VirtualDub (cautionary)

Set both "Video" and "Audio" to "Direct Stream Copying"

Use the "append" feature to load both new .AVIs and save with a new filename.

Again check to see if each of the new .AVIs are in synch...

[manono]

Well, that's much better advice than your first 2 posts in this thread (including the one you deleted). He doesn't want to reencode to MP3, as he's making a DVD, and it's not a good idea to degrade the audio quality any more than necessary by reencoding. And he doesn't want to make it for 22,050Hz, since he needs 48 KHz.

However, I don't really think you've taken into the account the out-of-synch audio he gets on the 2nd part. Maybe that has to do with him using VDub, which should never be used when VBR MP3 is involved. I guess we'll find out if he takes your advice this time. And since my advice didn't work out so well, here's hoping yours will.

And I don't have anything against you generally (unlike several others around here). The advice you give is often very good, as evidenced by the many replies of thanks you get. You obviously put in some serious time helping out around here, and it's much appreciated. But I really dislike you trying to trip up the newbies, who don't know your tricks. And I don't like you being unavailable for private messaging, so these things can be discussed privately.

[vio_man]

I finally was able to join the without any synchro issues. First I've demuxed the audio streams of both AVI's. Then I transcoded them to AC3 (using BeSweet, forcing sample rate to 48KHz), then muxed AC3 audio in AVI container. Finally I was able to join them using VirtualDubMod. The 2nd part loosed synchro, but I used the skew correction on the 2nd AVI and now I have the joined video with perfect sound on both parts. Finally :D
Thank you very much for your assistance.

[vio_man]

Yet another problem. Now I have 1 AVI, but when I convert it to DVD using Avi2DVD, somehow in the conversion process it manages to screw the 2nd part and losses synchro again :scared:
Maybe because when joining audio/video it does not use an audio skew correction... What can I do now?

[manono]

Hi-

I had to do this a couple of weeks ago. I had a commercial DVD where the audio was out of synch by half a second for about 2/3 of the movie, and in synch the rest of the way. I couldn't just adjust the delay, because that would then throw off the final 3rd. The movie came from 2 different sources and someone screwed up somewhere.

1. Split the AC3 into the 2 parts. I assume you have the original AVI with AC3 audio. If not, make one, split it and get the 2 AC3 tracks, one from the first part, in synch, and the 2nd part out of synch.
2. Find the amount of asynch of your reauthored DVD following the instructions from before.
3. Either cut it or add silence to it (depending on whether the audio comes before or after the video) using DelayCut. This can be tricky if you haven't used DelayCut before. If something has to be cut, the final AC3 will be slightly smaller than the original. If silence has to be added to the beginning, the final AC3 will be slightly larger than the original.
4. Now you'll have 2 pieces of the AC3 track with both in synch (with any luck).
5. Demux your reauthored DVD using PGCDemux.
6. Reauthor, adding in the 2 audio pieces one at a time, using Muxman to author. You'll see how you add them in when using it. The chapters are added in File->Import Chapters, and you give it the Celltimes.txt.
7. Test it out for synch.
8. If all is OK and you have a menu and maybe extras you want to keep, open the original out-of-synch DVD in VobBlanker and use the "Replace" button to replace it with your new and in-synch one. "Process" and test.

Maybe because when joining audio/video it does not use an audio skew correction

Very possible. That's why I suggested using DelayCut to fix the AC3. It adds silence, or actually cuts a bit from the AC3, so you don't have to use an actual delay in the DVD.

Or try out setarip_old's method, since you seem determined to get this one right one way or another. And just think how much you're learning in the process. :) Good luck.

[vio_man]

Before trying your method I did try converting with VSO's ConvertXtoDVD software and it did a great job, although the picture quality is not the greatest, at least everything is synched now. Case closed and thank you very much again :)