MP4 with 6 channel audio..

[nodollas]

I have an MP4 x264 with 6 channel audio that my Xbox 360 doesnt like.... I need to get this thing to 2 channel.
I ran the file through handbrake and it will play now, but the audio is out of sync.(actually seems to go in and out of sync)
Is there a way to strip the audio from the origional file, downmix(or convert) to 2 channel, and re-combine the two files and have them in sync ?
Thanks

[davexnet]

Open the converted video file in Avidemux. At Video (on the left) leave it at Copy.
At Audio, set it to aac or ac3, set the bitrate under "configure", and under "filters" set mixer to stereo
and choose dynamic range control.
Select mp4 under "format".

Save it as a new video: File/save video (give it a name including the extension eg. file.mp4)

[nodollas]

It says AVIDEMUX has a problem with H.264 and B frames....

[ricardouk]

1- demux (extract audio and video) from mp4 with yamb
2- convert to stereo aac using lamexp
3-mux the demuxed video from step 1 with converted aac from step 2 with yamb to mp4
4- that's it!