Crash on startup with an mp4 generated in May

[Jan Gruuthuse]

As I told you problem is not Avidemux? Thank you for not providing details as requested? Loosing my time on your problem: looks like I solved your puzzle: I have video/audio playing in VLC & avidemux.
download saved: https://rapidshare.com/files/3295280555/zakk.mkv 9MB
Zakk, give me 1 good reason to tell you how to do it?

[zakk]

Not possible. .ts sources are lost and the mp4 generated by avidemux are too big. Re-opening them with Avidemux make it crash (see first post). That's why I cut with mkvmerge. Really looks like a codec problem, not a container problem.

[Jan Gruuthuse]

Well It looks like after all to be a container problem and not a codec issue, how could I otherwise retrieve the information?
You can salvage your videos manually unless gruntster/mean provides a work around in avidemux.
download MKVToolNix 02 Sep 2012: Released v5.8.0
open video causing problems with mkvinfo, look for TrackID's:

...
+ A track
  |  + Track number: 1 (track ID for mkvmerge & mkvextract: 0)
  |  + Track UID: 1
  |  + Track type: video
...
+ A track
  |  + Track number: 2 (track ID for mkvmerge & mkvextract: 1)
  |  + Track UID: 2
  |  + Track type: audio

The bold above shows you track ID to use with mkvextract. In this case video is at track 0 and audio at track 1.
These become in the command line 0:video001 and 1:audio001
tracks = required mode, -f = parse fully
Filenames: whatever works for you, keep it recognizable for ease of working.

Code Select Expand

mkvextract tracks notworking.mkv -f 0:video001 1:audio001

Warning: Track 0: NAL too big. Size according to header field: 4, available bytes in packet: 2. This NAL is defect and will be skipped.
Extracting track 0 with the CodecID 'V_MPEG4/ISO/AVC' to the file 'video001'. Container format: AVC/h.264 elementary stream
Extracting track 1 with the CodecID 'A_EAC3' to the file 'audio001'. Container format: Dolby Digital Plus (EAC3)
Progress: 100%

You should now have 2 recovered tracks: video001 and audio001.
Start mmg -- a GUI for mkvmerge.
Add video001 and add audio001 and Start muxing
You should now have a playable mkv, don't forget to switch compression header off.
Source, documentation and downloads @ MKVToolNix

[zakk]

Well, Thanks Jan. I suppose once we understand each other we can manage something
A simple mkvextract + mkvmerge did the trick.
Funny how a simple remuxing was not enough (seems mkvextract makes a cleaner job).

[Jan Gruuthuse]

No problem zakk, happy this works for you. Language/cultural barriers and typed messages can do strange things to understand/communicate (with) people.
muxing with previous mkvmerge did some funny stuff to container, don't know what exactly, but they fixed that in latest release. (fps or audio sync related )