audio sync problem joining two avi files

[kthan]

I have two avi (xvid) files (50 min/700mb each) and want to join them before I convert them to MPEG2. Two files had different audio (mp3 and ac3). Since I found coverting them to ac3 incur a low volume issue, I converted them into mp2 by using ffmpeggui (mp2, 48000, 224kbps). Then, I disable original audio in virtualdubmod and add mp2 (new) audio and save it. At this point, new avi files (with new audio) plays perfect. But, when I join them
by using virtualdubmod (I also tried virtualdub and avi joiner), only the second avi (originally ac3) have audio sync issue (audio is faster than video). The first part (avi) (originally mp3) does have that issue. I am wondering if this is related to a conversion from ac3 to mp2. It doesn't look like it is related to a joining software becaues I tried two different software and got exactly the same result (audio sync in the second avi). Please advise me what to try.

[redwudz]

If your final product is a DVD, don't join them. That's where a lot of sync problems originate, from a bad join. The reason may be that they were cut badly from the original AVI and the keyframes overlapped. Or possibly a dozen other reasons. I usually encode the two parts of an AVI separately, then put them both into an authoring program and it will set them up to play consecutively with no joining needed. If each one plays by itself with no sync errors, but has them when joined, this is usually the best way.

If they had different audio formats, this would be another good reason not to join them, as I would definitely suspect the two not to match up on sync.

[kthan]

I just found that the sync problem has nothing to do with original files or two different audio file format. I put two files in reverser order and join them for a test. The second avi files (that had sync problem...originated from ACS) plays just fine. Instead, the first avi file (that played fine) had sync problem now. So, the problem occurs at the time of joining, as you guess.

Hmm... I needed joining avis because I want to use "convertxtodvd" program. It not only gives very easy and simple converting (actually output exactly matches to the original) but also the output file size is just less than 30% of the other programs, like TMPEGenc and CCE. The original xvid file was 700 - 730mb each and the output file size was only 1.3Gb. When I convert the same file at other programs and the output file size was about 2 - 2.3 GB per file. Plus, its encoding process is very fast (usually, 1.25-1.3x).

I might try to separately encode them at convertdvdx and, as you suggested, put them together in an authoring program. But, this program is kind of all in one, including authoring function (like chapter creation). I am wondering if I did it with this program and use an authoring program for joining purpose. Also, I was told that not all program can join two videos together. Which program (dvd-lab pro, TMPEGnc or else) would you recommend (for easy and simple processing...I don't need any subtitle/extra menu things)?

[redwudz]

ConvertXToDVD should be able to accept the two separate AVI files and convert them to a single DVD file. Just use 'Add video file' for each. Or doesn't that work for you? I don't know if your sync problems will reappear when you do that. You 'might' have to set both audio formats the same, but you wouldn't need to join them.

I use ConvertXToDVD for SVCD to DVD conversion and the videos are always on two discs. I haven't had any sync problems with them.

[nightcat]

kthan,

Hi. I often use the Womble products namely MPEG Video Wizard to join my avi files with different audio format, and then export them to MPEG-2 file. I haven't met any sycn problems.

So I would recommend the this product to you.

-Nightcat

[joanofark06]

I wanted to put a lot of videos on one certain specific subject, from YouTube, on a DVD, but I wanted them to play in my order of arrangement. They wouldn't burn in the order I wanted them with any and every DVD burner I had. So on reading up on how I could get my videos to burn in the order I wanted them, I found out about File Joiners. It worked and I thought I was done. Then the audio sync problem popped up. I thought it was the joiner I downloaded. So I kept downloading and deleting joiners to the dismay that it wasn't the joiner. So in more studying up and reading, I downloaded and then deleted a few audio synch programs untill I found one that worked for me and I liked ( AVI-Mux_GUI-1.17.7). When I got the first video perfect, I thought the whole video was right now, but no. The first one I got perfect, but then the second one was out of sync. I guess I should find a splitter now, and fix the audio in every video seperately? I just wish there was a DVD burner that would burn my videos in the order I want them. Is there such a thing? Thanks in advance for this site, for letting me voice my frustrations, and for anyone that can help me.

[Gavino]

I wanted to put a lot of videos on one certain specific subject, from YouTube, on a DVD, but I wanted them to play in my order of arrangement. They wouldn't burn in the order I wanted them with any and every DVD burner I had. So on reading up on how I could get my videos to burn in the order I wanted them, I found out about File Joiners.

I assume these are xvid/divx files burnt as a data disc, not an authored DVD.
Have you tried simply burning them one at a time, in the desired order?

Or create a new folder on your hard drive, copy the files into it one at a time in the desired order, and burn from that folder.

[joanofark06]

Yes, they are files from YOUTUBE that I converted to AVI video files (all seperate)and are in a folder on my hard drive, and play just fine. (Wont burn on any dvd player "in order" I want, that way) I have another folder that holds the files joined together as one complete AVI file, (COULD burn them on dvd now in correct order now), BUT I cant stand that the audio is out of sync. I found software that fixed the "first" video's audio in the whole joined avi file (using AVI-Mux_GUI-1.17.7, but when it came to the second, third, etc joined video, the audio was out of sync again. If I could figure out how to break the complete AVI file into chapters, or use a splitter, and fix the audio in each one that way? ......I'm still working on it, and new at this.....lol P.S. Cant author it with DVD Shrink, I've tried but might go try again. I even made an image of the video files and put it in a folder on hard drive in the order I wanted them with Imgburn, but when I burned that same .iso image with Imageburn to dvd, the files were alphabetically, and NOT in the order I put them. Go figure!! Burning them one at a time?? I think that would take too much work...10-15 individual video files...

[video-phile]

kthan
Are you sure that the audio and video track whithin each avi file have exactly the same duration?

[dylz]

I'm guessing they aren't part1 and part2 of a video or movie because they have different audio formats(mp3,ac3). You could try to append them after converting the audio to ac3 and should be able to adjust the loudness by rightclicking the audio stream in vdubmod if not try advanced filters, do you have lame acm installed to encode mp3? http://www.softpedia.com/get/Multimedia/Audio/Audio-CD-Rippers-Encoders/LAME-ACM-Codec.shtml so if you don't like ac3 use mp3 then join them by appending and direct stream copy the video and audio.

Make sure there's no delay in the audio.

[Gavino]

Yes, they are files from YOUTUBE that I converted to AVI video files (all seperate)and are in a folder on my hard drive, and play just fine. (Wont burn on any dvd player "in order" I want, that way)
...
I even made an image of the video files and put it in a folder on hard drive in the order I wanted them with Imgburn, but when I burned that same .iso image with Imageburn to dvd, the files were alphabetically, and NOT in the order I put them. Go figure!! Burning them one at a time?? I think that would take too much work...10-15 individual video files...

Well, probably less work than messing about with sync problems.
It's possible that your player always plays the files in alphabetical order, no matter what the physical order on the disc. (Especially if it displays an alphabetical list for you to choose.)

How about renaming the files - just stick 01, 02, etc on the front of each.
Surely that can't be a lot of work, and is worth a try?

[video-phile]

I just found that the sync problem has nothing to do with original files or two different audio file format. I put two files in reverser order and join them for a test. The second avi files (that had sync problem...originated from ACS) plays just fine. Instead, the first avi file (that played fine) had sync problem now. So, the problem occurs at the time of joining, as you guess.

Hmm... I needed joining avis because I want to use "convertxtodvd" program. It not only gives very easy and simple converting (actually output exactly matches to the original) but also the output file size is just less than 30% of the other programs, like TMPEGenc and CCE. The original xvid file was 700 - 730mb each and the output file size was only 1.3Gb. When I convert the same file at other programs and the output file size was about 2 - 2.3 GB per file. Plus, its encoding process is very fast (usually, 1.25-1.3x).

I might try to separately encode them at convertdvdx and, as you suggested, put them together in an authoring program. But, this program is kind of all in one, including authoring function (like chapter creation). I am wondering if I did it with this program and use an authoring program for joining purpose. Also, I was told that not all program can join two videos together. Which program (dvd-lab pro, TMPEGnc or else) would you recommend (for easy and simple processing...I don't need any subtitle/extra menu things)?

Hi again! Whatever the case I think there is a way to avoid audio sync problems when merging: convert avi files to vob files (use your favourite authoring tool). Then merge vobs and add ifos using this guide or use tmpgenc author which can do it all very well (import vobs into a single track, add custom chapters etc).