I typically just copy over audio and don’t encode it out from the original. But I’ve come across a file that has he-aac that ends up causing transcoding on my plex server when watching from roku. All my other audio formats are direct play and don’t need to transcode. So I’m trying to figure out how to have MCEBuddy ac3 passthrough only he-aac and the rest just copy. I tested the ac3 passthrough in Handbrake GUI and the file was exactly what I needed.
After a lot of trial and error the following values worked for me.
handbrake-audio=--aencoder copy --audio-copy-mask ac3,eac3,truehd,dts,dtshd,mp3,flac --audio-fallback ac3 -R auto
handbrake-audioac3=--aencoder copy --audio-copy-mask ac3,eac3,truehd,dts,dtshd,mp3,flac --audio-fallback ac3 -R auto
Since aac is not specified in the audio-copy-mask it will fallback to ac3. This worked exactly how I wanted it to without affecting other formats that I want to do straight copy of.