MKVtools (formerly MoKgVm2DVD) is an OS X application that I developed to provide the tools needed to prepare .ogm and .mkv files for use in DivX enabled DVD players. Even if this is not your goal, you may find MoKgVm2DVD useful in handling these two types of files.
Features:
Convert .mkv and .ogm videos to .avi files.
Intuitive track selection with the ability to verify the selections using video preview.
Can either pass-through the selected video track (fast) or re-encode the track using either a 1 or 2 pass XviD codec.
Can either pass-through the selected audio track or re-encode the track using the mp3 codec.
Embed the selected subtitle track (i.e., hard subtitles) into the new file though this requires that the video track must be re-encoded.
Control the font, size and positioning of the embeded subtitles.
Create a user-definable test clip to check settings.
Extract the selected tracks as individual video, audio and/or subtitle files.
Add jobs to a queue either individually or in batches
