I cant believe you were seriously going try to email a file that is 342Mb in size.
This would take forever to upload from your computer, and the person getting it, if they are on a slow broadband, will take an age to download it.
Even if you upload it to a file sharing site it will still take a long while to upload from your computer to the file sharing site, and a long time for the other person to download.
If you reduce the quality of the video it will become a smaller file and easier to send someone else.
Still too large for email, but not so large to upload and download.