if in step 5 the a/v syncron at the begining, but lost synchron after 40m35s120ms, and the "40m35s120ms" is the change point. This is your 1st asynchr point. Go to next step: 6. Estimate the time diff. of asynchr and set the value of audio delay in VDub. Repeat it till the a/v synchr after the 1st asynchr point. Write down the asyn-point and the value of delay. 7. unload the wave file in VDub, load the wave file in WaveLab(or your favourite weve editor) and add or delete a few time at the asyn-point with the value which you've got in step 6. Save wave. 8. reload the wave in Vdub and go on checking, if there is a 2nd asynchron point, determine it and repeat the step 6,7,8.