Trim M4V file without re-encoding

[marioval]

I have a short 20 minute m4v file that i want to cut the first few minutes from. I tried in avidemux using "copy" for video and audio but the resulted file shows as 9 hours long in all media players (vlc, mpchc, etc) and if I try to jump to another part of the video it crashes the player..... I then tried xvid4psp using the trim feature and "copy" for audio and video but the resulted file still included the part I thought I cut out. Can some recommend another software? Thanks.

[Baldrick]

I guess you did used the mp4 container format in avidemux?

You could try "fix" the cutted mp4 headers by remuxig it with mymp4boxgui, just add the mp4, then create a new mp4. It works some times.

[marioval]

Yes I did use the MP4 container in avidemux.... I already deleted the "fixed" output file but still have my original. I tried trimming with MPEG Streamclip and saved as an MP4 without re-encoding. The output file shows as the correct duration and allows me to jump to different points in the video. The audio/video is perfectly in sync. The problem is that when I copy it to my PS3 and play it from there, the audio/video is out of sync. I though it may have been a bad copy so I deleted from my PS3 and copied it again but same sync issue. I also tried streaming to the PS3 using TVersity and same sync issue. What gives?? I'm also going to try running my new MP4 through mymp4boxgui as you suggest to see if that takes care of the sync issue.