You said that the source was a camera, so I didn't know you that you are dealing with fixed sized video. The bitrate of the video will make up the bulk of the file, so if you limit the maximum bitrate of the video, the output video will be less than 650 MB.
You can produce a fixed rate video or control the bitrate tolerence, to make your calculation easier.
I seem to remember being able to control the bitrate via a feedback mechanism while the transcoder is running. I don't remember which program. It might have been transcode.
Last edited by jschiwal; 04-13-2012 at 12:51 PM.