I have tried absolutely everything trying to get my GoPro footage to render correctly, but it is still not rendering properly. The raw footage plays just fine, and when the file is in Vegas, it plays just fine, but when I render it, the video is extremely choppy/laggy. I have tried just about every render setting, and made sure they match the project settings, but nothing is working. PLEASE HELP!!
I see you have removed the video from YouTube. Does this mean that you found a solution? Have you tried using the CineForm Studio software - http://gopro.com/software-app/cineform-studio - available from GoPro. It provides tools for making edits and converting the video files. You could try converting the video before bringing it into Vegas with CineForm. It is definitely worth the download and it's free.