Nope. The iPhone sends its videos via a web server, not MMS, hence the video quality is unchanged. It works like sending a video over Viber, Hangouts, or Whatsapp.
If you want to send a video, you'd have to use Hangouts. It's actually the app that works exactly like iMessage, wherein webchat and sms are integrated and you can send full uncompressed videos. The other person needs to be on Hangouts too though. For some reason this didn't take off well enough with Google users as much as other iMessage did with iOS. Most people never bothered activating it.