Noe,
Firstly, welcome to Apple discussions. Always try to make your Topic heading specific to your topic. You should get better response by doing this.
As far as your video goes...check your audio compression on your video.
Apple suggests...
* By following the steps in this tutorial, QuickTime 7 Pro will automatically create an .m4v file containing H.264 video and AAC audio that is optimized for iPod. iPod can play the following video formats:
H.264 video
File formats: .m4v, .mp4 and .mov
Video: Up to 768 Kbps, 320 x 240 pixels, 30 frames per second, Baseline Profile up to Level 1.3
Audio: AAC-LC up to 160 Kbps, 48 KHz, stereo audio
MPEG-4 video
File formats: .m4v, .mp4 and .mov
Video: Up to 2.5 Mbps, 480 x 480 pixels, 30 frames per second, Simple Profile
Audio: AAC-LC up to 160 Kbps, 48 KHz, stereo audio
