Audio Swapping problem

[Hyde]

hello, i'm trying to use the audio of an avi on another avi. this is what i got:

Movie A in 1 650MB avi - bad video good audio
Movie B in 2 770 MB avis with commercial at the bigginning - good video and bad audio

so i'm trying to get the audio from the Movie A and replace it on the Movie B.

First i join the two avi files of Movie B using virtualdub. Then i save only the video disabling the audio.

Second, i delete the commercial at the begin of the movie and save it back again.

when i include the audio track taken from Movie A (demux as wav), a strange thing happens.... playing the movie, i hear that the audio doesn't start from the begin while playing only the wav, it does.

What's happening? am i doing it the wrong way? is there another way? thanks.

[Hyde]

Nobody knows how to help me on this? i thought it was an easy thing! maybe my problem hast has something to do with frames, keyframes or rates?

[Baldrick]

has the joined avi and the wav exact same length?

[Hyde]

no, different lenght