Audio Sync Problem

[Cleo]

I have been having a problem recently with audio sync of two files. Now these two files apparently are actually 1 file which was split after encoding. I am not sure if the split is what caused the audio sync problem or not as I downloaded these files off the internet and did not encode them myself.

The thing is when I try to load them into virtual dub I get this message:

VirtualDub has dectected an improper VBR audio encoding in the source avi file and will rewrite the audio header with standard CBR values during processing for better compatibility. This may introduce up to 0 ms of skew from the video stream. If this is unacceptable decompress the *entire* audio stream to an uncompressed WAV file and recompress with a constant bitrate encoder. (bitrate: 128 +/- 0.0 kbps)

The thing is when VirtualDub does this the file plays exactly as it should with no sound skew.

I have tried to fix this file several ways. I have saved the sound as a wav file and tried adding it into the video file. I have tried changing the framerate and I have tried interleaving. I also tried divfix and that didnt work either. It seems that in some places the audio is more ahead of the video than others so that merely delaying when the sound starts on the video doesnt help because it will sync at the start but then a few seconds later its off again because the sound is not out of sync at the same rate. I am at a loss as to what to do. Is there any way I can save it so that it works like it does when I play it in VirtualDub?

Any help would be much appreciated.

[manono]

Hi, and welcome to the forums-

You should be using Nandub for your synching. VDub can't handle VBR MP3 audio. I didn't understand all of that, but it sounds as if you have a progressively asynched audio track. You should have a look at Doom9's VDub Guide (http://www.doom9.org/virtualdub_procedures.htm), and about a quarter of the way down is a big section on synching the audio.

[ihgl]

Since skew is 0 there is not really a problem in VirtulDub. It will play as is. I very often make SVCD:s out of AVI:s and really dislike VBR audio. It is not really standard and noncompatible. Nowadays I allways use CBR even if it gives you somewhat bigger files. It is safe and you can take it to the bank. This is my method: Load the file into VirtualDub. Chose Full Compression Audio and save as a Wav-file. Then convert the Wav with Lame into a CBR Stereo 44.1 192kb/s mp3-file. (suggested values)Then save your original file in VirtualDub with the No Audio option. Now you have a separate video and a separate mp3-file. Join the two with VirtualDub Mp3 version or Nandub. If audio does not play correctly this way you are in to big trouble due to faulty original and that is another hard matter. All this said also will work very well if VirtualDub complains over a great skew ie 44500 ms and so on.

Hope people out there stops making VBR-Audio ;-)

[Cleo]

Thanks for the help. I tried all the methods suggested on doom9 so far and none of them worked. I will try yours out and see. Seems like its the VBR audio to me since it plays fine when VirtualDub converts the values to cbr.