How to compress .mp4 HD

[LOLROB]

Well I've started to use my flip ultra HD camcorder and I uploaded a video to youtube yesterday and it was 300mb for 3 mins 30 seconds and because I am on slow internet It took about 2 hours and I've made a new video today which it is being put together looks to be about 500 - 700mb's and I need to find a way to compress it.

I downloaded a converter and converted it to .mkv and it got 120mb's down to 19mb's which is fantastic but its not that good quality

any way I can compress this HD .mp4 file down with out losing much quality

[The Professor]

Try making the audio mono and setting it to a lower bitrate (128 or somewhere around there), that usually knocks a bit of the file size. If you're not bothered about it being HD, take the resolution down to 640*480, on youtube that should look fine. You can also probably get away with 25 fps with it looking ok.