Why is my .mkv video so big?

[Vorpike]

I had a lot of problems with this 7Gb .mkv file, like formatting my USB to NTFS. But I'm done with my theories on how to solve this and to turn to you guys. Why is my 2 hour long video so damn large? I'm thinking it's because its loaded with 4 sets of subtitle, each with their own fonts, but when I tried splitting it with toolnix, I got 4 files that were around 2Gb each, but were, for some reason, 3 hours long. I couldn't scrub through the video to verify that its correct, because this huge file is really laggy, and I can only watch it from start to finish without searching through it (not an option). So my questions are, why is this short video so large in size (the resolution is only 700), and how do I make it so I can actually scrub through the video?

[TypX]

You may have several audio tracks, subtitles don't take that much space, it's only text. Fontfiles won't take such a big size, if you can reach 100MB of fonts then it's really bloated. In any case most of the space will surely come from the video track. Video size matters but not as much as the various encoding parameters, like codec, bitrate, profile etc...

In any without the file description it's only a wild guess. To be sure you could use MKVExtract to get each element and see what's its size.