Is there a way to just re-encode audio with Bd-Rebuilder?

I am more of a video fan than audio and was just wondering if there is a way to shrink just the audio using Bd-Rebuilder and leave the video alone. I used TsMuxer to cut out all the extras of a movie and ended up from 42gigs to 28gigs. So I just need Bd-Rebuilder to re-encode the audio and shrink it, audio which is already Ac3 by the way.

[QUOTE=freestylp0laris;2283451]I am more of a video fan than audio and was just wondering if there is a way to shrink just the audio using Bd-Rebuilder and leave the video alone. I used TsMuxer to cut out all the extras of a movie and ended up from 42gigs to 28gigs. So I just need Bd-Rebuilder to re-encode the audio and shrink it, audio which is already Ac3 by the way.[/QUOTE]

The only way to reduce the MBs of the audio stream would be to use TSMuxer to demux out an HD audio stream into an elementry AC3 stream and then remux it back into the movie m2ts file.
If you are trying to reduce it further by changing it’s bitrate, I’m not sure it would even work with Audacity or the like.