If the video was re-encoded with x264, which is very likely, you can easily find the encoding settings by running Mediainfo. Once you have them, you can easily replicate them, either by using the command line or by recreating them in a GUI. The latter might be more difficult as some GUIs might not present the user with certain settings.

The unknown element is processing. If the video has been processed, it's not always easy to work out how and with what settings.

Assuming the video has not been processed and you have access to the same source, it is easy to make an MKV containing video of the same quality as someone else's.