Append mp4 (x264/aac) files?

[ZZZERO]

I have a movie split into 3 mp4 files that I want to join into one file. They are enocded with x264 video and Nero aac audio. I've tried with avidemux but the audio sync goes way off. I'm using the copy settings for both audio and video in avidemux. Is there another free program I can use to merge these files or does someone know a way to do it in avidemux without losing the audio sync?

[burfadel]

You can use YAMB :)

[ZZZERO]

Thanks. That joins the files without the audio sync problems avidemux was having.