Joining two MP4 files

[biomech]

Hello all,

I've read many topics about joining MP4 movies, but however much I try I end up with poor results. I'm trying to join these two files (I used GSpot to get this info):

File 1:
- Video: H.264/MPEG-4 AVC, 836 kbps, 25 fps
- Audio: MPEG-4 AAC LC, 48000Hz 129 kb/s tot , stereo (2/0)
- Resolution: 640x272

File 2:
- Video: H.264/MPEG-4 AVC, 703 kbps, 25 fps
- Audio: MPEG-4 AAC LC, 48000Hz 129 kb/s tot , stereo (2/0)
- Resolution: 640x272

(if more info is needed I will provide it)

I tried to append the two together with Avidemux, but the resulting file had popping/clicking noises in the audio and the sync was off during the second portion. I've tried other software such as YAMB but still had the sync issue.

Some help would be immensely appreciated on how I can join them together and preserve the audio/video quality and sync, thank you!

[vhelp]

Unless the source of your troubles is VFR (variable frame rate) the following is just a wild guess..

Since its an audio problem, you could try converting (both AAC) back to wav and then re-encode them to AC3 or back to AAC and then use:

MP4box -add file1.mp4 -add file1.aac -fps 25 -add file2.mp4 -add file2.aac -fps 25 newfile.mp4 on them.

I hope I got that command line setup correct.

-vhelp 4894