As discussed on the Tools page, MKVtools is an Applescript Objective C application that acts as an interface for a number of UNIX commandline applications. So if you encounter problems with MKVtools, chances are that it's an issue with one of the UNIX applications.
To help evaluate causes of strange behavior, you can select to keep the log files that are created during processing. This option is found in the MKVtools preferences . Examining these log files should give you some hints regarding what the Unix applications are having issues with. The web sites for the individual Tools could also prove helpful.
Probably the best resource would be useful Mac video forums found here or here.You'll find lots of people there willing to help and with more knowledge about general video issues than I have. Also, I periodically read this forum and can chime in with specific MKVtools issues.
- The following error message can occur on Snow Leopard - Library not loaded: /usr/lib/libXplugin.1.dylib: With Snow Leopard, Apple no longer installs the libXplugin unless you install X11. Fortunately there is an easy fix. Insert your Snow Leopard CD, open the Optional Installs folder, and launch the Optional Installs package. Follow the steps until you get to the point where it lets asks what components you want to install. Open the Applications category in the list and enable X11, then install.
- Mencoder crashes at some random point during processing: This doesn't happen very often, but I've seen it every once in a while for certain files. Unfortunately, I don't have much control over this.
- Mencoder ignores selected external subtitle tracks: This can be an issue if the original video also contains an "internal" subtitle track. You may also see the internal subtitle track is used instead of the external subtitle file. This appears to be a bug with the version of mencoder used. A workaround would be to first delete the internal subtitle file(s).
- The output video is missing, smaller than it should be, or is not playable: Probably due to a codec problem (i.e., how the original file was encoded). Try looking at the log files as mentioned above, to look for error messages from the various tools used. Chances are that your video has some codec that mencoder does not support.
- Closing the mplayer window using the close button in the title bar sometimes causes an error: This is a bug in mplayer used by MKVtools. Use "q" instead to quit mplayer
- The resulting video has major audio sync issues: For MKV conversion, the problem is probably with the frame rate (fps). Some videos report an incorrect frame rate, which will result in out of sync video. The MKVtools lists what it thinks is the correct fps. If your video's audio is out of sync, try a different value from the menu.
- Subtitle preferences are ignored during conversions and/or playback: There seems to be a bug where mencoder and/or mplayer will sometimes use the mplayer default subtitles regardless of user settings. These default subtitles are only on your computer if they were installed by some other program. There is a work around if this is an issue for you, though it involves digging around in hidden folders.
Here's what you need to do:
There are different ways of accessing hidden files/folders so I’ll leave that up to you (Google is your friend). Once you have access to hidden files/folders, you need to find mplayer’s “font” folder. I found it in “My Startup Disk”/usr/local/share/mplayer, though the Mplayer documentation says it is typically in the .mplayer folder in your home directory. It could be elsewhere so you might have to do some exploring.
The font folder should contain other font folders (probably arial fonts which you can leave alone), and, what you’re looking for, some font information files including “font.desc”. These are the default files that mplayer/mencoder uses. If you move these files to a new location, your subtitle settings should work. Note there are no guarantees on how this will effect other applications that use mplayer.