converting .webm to .mp4

File: 1298732538337_U18chan.png (1MB, 982x1167px) Image search: [Google] [Yandex] [Bing]

1MB, 982x1167px

suggestions for doing this for free?

i've tried formatfactory, it failed; i've tried VLC, it crashed; i've tried a worthless online service called Zamzar; they wanted money before they'd email the converted file to me.

there are dozens of conversion programs available according to google, but i'm concerned they will all ass-rape my machine. the ones with webpages loaded down with huge animated gifs saying

"TOTALLY NOT A VIRUS"

and

"TRUSTED VIRUS FREE BY JOHN MCAFFEE HIMSELF, HE SAID SO LAST TIME HE WAS SOBER"

aren't much consolation. btw the webm is nsfw, could i post it to the appropriate tumblr and they'd convert it to HTML5 which, i think, is mp4 basically?

pic sort of related