joining 3 xvids

[sander815]

i have 3 short avis that i want to join., all around 5 minutes long. The problem is, only the first capture is in sync. The next two appended videos have early audio: number 2 is approx. 1/2 second out of sync, number 3 is approx. 1 second off.
All 3 vids are 2pass xvids, with mp3 sounds

Each capture by itself is perfectly in sync; only when they are appended together do they go out of sync. It's like the audio cuts off 1/2 second before the video. So, when you append the next avi, the audio begins 1/2 second too early.

So, is there something I can do?
I tried reencoding each vid with same bitrate, but no succes

i tried avimux, then the 1st and 2nd are in sync, the 3rd is not

[CWR03]

You could demux the audio and convert it to .WAV, then append silence to the beginning of each segment as needed and remux. It would be a matter of trial and error, but it should work.

[sander815]

ok
but why are they out of sync anyway, while the video play fine seperatley?

[sander815]

strange
when i join 1 and 3, they are both in sync, when joining 1, 2 als in sync, when joining 1,2 and 3, 3 is out of sync

[CWR03]

The audio on 2 is probably short, which is why I made my recommendation.

[setarip_old]

Hi!when i join 1 and 3, they are both in sync, when joining 1, 2 als in sync, when joining 1,2 and 3, 3 is out of syncAnd what happens if you join only 2 and 3?

[sander815]

i delayed the audio on track 3 to around 800 ms, and it seems ok now
odd kinda workaround, but it worx

[Revgen]

i have 3 short avis that i want to join., all around 5 minutes long. The problem is, only the first capture is in sync. The next two appended videos have early audio: number 2 is approx. 1/2 second out of sync, number 3 is approx. 1 second off.
All 3 vids are 2pass xvids, with mp3 sounds

Each capture by itself is perfectly in sync; only when they are appended together do they go out of sync. It's like the audio cuts off 1/2 second before the video. So, when you append the next avi, the audio begins 1/2 second too early.

So, is there something I can do?
I tried reencoding each vid with same bitrate, but no succes

i tried avimux, then the 1st and 2nd are in sync, the 3rd is not

I always have these problems when trying to merge avi clips. The only way to deal with it is to adjust the audio sync manually.

Now If you're trying to merge clips for encoding to something else you can use UnalignedSplice or AlignedSplice in avisynth to try to get a good sync.

[phædrus]

I searched for a thread like this because I had the experience today of joining five clips which were perfectly in sync when played separately, and when joined in VDubMod the audio gets progressively ahead of the video, worse after each join. This is maddening.

Now, I would consider joining two files together without frakking (can I say frakking?) up the audio to be a basic function of this type of software, and the lack of the software's ability to do this akin to a bug. There is no point in complaining that this function is absent, obviously no one considered it important enough to solve, and I don't have any programming skills to fix it, either. So I guess this glitch will have to be worked around, the hard way. But I am really floored that something as simple as joining two perfectly good clips gets to be this difficult.

It would appear then that the audio is a little short on the end of each of my clips. The audio from the following clip is joined to the short end of the first clip, etc.

Is there any way I can tell exactly how short the audio is on the end of each clip, so I can introduce a correspondingly precise and accurate delay in the next clip? I don't want to have to do endless guesswork here.

Heeeeeellllllp.

[foxyshadis]

The info window has lengths of both streams, to a precision of a hundredth of a second. That should be sufficient, if not you'll probably have to rip into one of the avi parsers out there.

MediaInfo does report to thousandths, but only for the video; you have to calculate the audio length from the # of samples.

[sigma6]

This is the solution for joining 3 or more avi files. Even sometimes is better for joining 2 files than Nandub, VirtualDub or VirtualDub Mod. Especially, when you get clicks at the join or there is no sound after the join.

http://www.alexander-noe.com/video/amg/

:thanks:

[HeadBangeR77]

My method (that usually works, not always though) is to demux audio from each part and work on it separately, of course comparing their length with video stream. Parts mean the audio was cut /split once, and the header is usually screwed, having wrong length information. Correcting it (e.g. MP3 VBR with BeSplit/BeSliced), joining together, and then muxing with the already joined video stream seems to work for me in most cases.

@ sigma6:
Yeah, AVI-MUX is suitable for the task. :)