Bad sync in the beginning of a movie

[mazzo]

When I work with avi's recorded from tv, I experience that there is a lag in the audio/video sync in the beginning of the movie, the audio is a little behind. In the middle of the movie it's better.

The wav file and the avi are exactly the same sizes, down to the 1/1000 second.

Is lame performing any bad tricks here?

[hakko504]

Quite possible.

Do you use vbr or cbr audio?

[mazzo]

vbr - i think, yes, i'm positive.

--abr etc.

[hakko504]

ABR is a form of VBR

Check this. (http://forum.doom9.org/showthread.php?s=&threadid=40725)

[mazzo]

Is it this simple:

take a note on the length of the movie.

Do the wav->mp3 conversion

Find the length on the mp3

And then, when encoding the movie, put the difference in length in the delay field, and then just mux the encoded mp3 audio?

[hakko504]

Unfortunately not. You can get audio that starts before the video and ends after, as well as vice versa. In MPEG-2 (DVD/DVB) there are timestamps that will keep the audio in synch no matter what. These do not exist in AVI files and therefor every block of audio should always be a specified number of samples. Since the block sizes of vbr vary, this is not always the case when you lock the size of the audio interleaving.