Does anyone know how to take a video and re-encode the audio, but just copy the video data using FFMPEG?
So Apparently FFMPEG can do this, I had to use
-c:v copy and that will leave the video stream intact. I actually used an app called iFFMPEG to figure this out.
I know that Virtual Dub can do this, but it only works with a limited number of codecs. Since it's free, it's worth a look to see if it'll do what you want.
Otherwise, any demux/remux software will work, but it'll take three steps. First demultiplex the file into video and audio streams, re-encode the audio as needed, then remux them into a combined stream.