Trim selection in MKV without losing timing info

[dstarfire]

The situation:
I've got an mkv with the audio and video go out of sync (by a set, unchanging amount) at a certain point in the clip. For some reason my preferred player, smplayer (14.3.0, the current version), can't get the audio in sync no matter how I adjust the audio delay. I'd like to post segment where the audio goes off sync to get some feedback about what's wrong with the file. However, this total file is over 2 hours long, and a copyrighted material, so sharing the entire thing will simply not work. Plus, the vast majority of it works just fine.

What I'm trying to do:
I'd like to extract just a ~2 minute clip that covers the transition from audio correctly sync to unfixably lagging. In my experiences with de- and remuxing files I've never been able to match the syncing of the original (and capturing the syncing is the whole purpose of this exercise). Is there a tool that can extract a clip from an mkv without losing the sync info? Supposedly Solveig's avi trimmer can do it (according to their promo video), but I'd appreciate some suggestions from a less-biased source.

[Baldrick]

Have you tried mkvtoolnix / mkvmergegui ?

[johns0]

Just rip the disc again or download it again from where you bought it since it's copyright.

[El Heggunte]

Insufficient information

Please post a MediaInfo report about the MKV. Maybe the file was muxed improperly, maybe Mplayer doesn't like the way it was muxed, maybe it contains Vorbis audio which is evil by definition , maybe you should add the option -demuxer lavf to the command-line, etc Etc ETC.

[Hoser Rob]

I suspect it's a warez download and, like many of those, is a crap encode made by someone with a mess of bad 3rd party codecs installed on their system. No sympathy here.

[dstarfire]

I suspect it's a warez download and, like many of those, is a crap encode. No sympathy here.

You misunderstand my intentions. I'm really just curious about what the encoder did wrong. Fixing it is beyond my abilities (as I mentioned in the OP, I can't even remux a video without losing the timing, and that's using mkvextractgui and mkvmerge). At most, I'd pass along a sample to the sm/mplayer devs as a case where the audio delay doesn't behave properly.

I'm hoping there's a tool that will let me pull out the minute or so where it goes from being properly in sync to being unsyncable in smplayer (along with the necessary headers from the container).