How to Proxy edit huge 500mbps MJPEG files from the 5D Mark IV in Vegas Pro
Proxy Editing in Sony Vegas
Post updated January 2018: One of the biggest problems when shooting MJPEG video at 500mbps, is the "weight" and size of the files it produces. Even with a powerful computer, the timeline playback when editing can be rather choppy. If it plays at all.
One way around this is to transcode the clips to a more manageable codec. Something like pro res but another method, if your editing software allows it, is to use proxy editing.
I use Vegas Pro for a lot of my editing and versions 12, 13, 14 and 15 all allow proxy editing. It is a very simple process and creates a much smaller proxy file alongside your original file (in the same folder) that makes playback super smooth.
Later versions of Adobe Premiere Pro also allow proxy editing for video.
If you prefer to go the transcoding route, go and download Vidcoder. Vidcoder is free and trustworthy. To give you an example of how effective it is, I just took an 884mb MJPEG file from the Canon EOS 5D Mark IV. After transcoding, it output a high quality MP4 file at 107mb that is easy to preview and edit.