Hlöðver Þór Árnason

Just found out that audio on the 3GP videos made with HTC desire doesn't work out of the box when playing on Windows 7. It's using the SAMR codec which is proprietary. In order for it to work you can either install Quicktime or install the codec separately. The audio even fails on VLC! Who would have believed that!?! Read more about this issue here.

Update 04.08.10
At least you can use WinFF to convert the videos on Windows if you use the latest FFMPEG binaries.