I'm trying to shrink some mpg-files with ffmpeg. The mpg file is 8 hours long. It's OK the first hour or so, but after that the picture is slightly before the sound. I tried AviDemux but you can only set the fps to the third decimal. 24.996 is too slow and 24.997 is too fast. At different parts of the movie I have to set the fps to 25.000, 24.998, 24.997, 24.9965, 24.996, 24.995. If I set the fps to 24.995 the sonud comes before the picture in the earlier parts of the mpg. I have used mencoder earlier for other purposes but when I did the sound was out of sync when played on my Windows machine.