Now all video editors out there for AMV's fan-dubs, anything really will have encountered .MKV's a file type that helps compress video and make for easy watching. HOWEVER they cannot be used with programs like after effects and Sony Vegas. now the most common thing to do is spend hours doing a large convert which probably looses some quality. But today i feel i should show you a much simpler way.
STEP 1: Download MKV Extract GUI and My Mp4Box Gui. What these allow you to do is create a data file from the MKV's and from there creates an MP4 file that hold this data. It is close enough to lossless.
LINKS: MKV Extract Gui My MP4 Box
Step 2: Open MKV Extract Gui and do as follows
This should create separate files for each channel you have ticked.
Step 3: Next Open My Mp4Box Gui and do as follows
I hope this helps!