www.makemkv.com

I have about 12 hours of footage from a concert that I'm converting, but most of it just cuts off in the middle and then starts at the very next frame in the next video file. I'm wondering if it would be possible to convert multiple files at once into a single file. Is there any way to do this?

Use the Append option in MKVmerge and it'll take several files and output it to a new, single file. Just be sure to append them individually to make sure you put them in the right order.