Video was not copied to the iPod because it cannot be played on this ipod.

I have a mp4 file that won't sync to my iPod 4th Gen.

The file is H.264, 720p, the bitrate is 1415 kpbs. Could the problem be that is has a stereo and a Dolby Digital 5.1 audio channel? It was an mkv but I used ffmpeg to change the container.

Any help apperciated!

Thanks.