Hi Zedstrain, I’m guessing we’re talking about movies’ audio tracks. Passthrough is always best if we can stomach the storage space, especially if the video is taking a lot more space anyway.

If compressing, why not opus? Should be at least slighly better than AAC, it’s constantly improving and thanks to its licensing the encoders you’ll find included in any up-to-date software like Handbrake should work really well.

With AAC (which does sound great and is very close to opus) you’re gonna see bigger differences depending on the encoder. I only used it for music and podcasts (when I got into modding classic iPods 😂), but to avoid installing encoder libraries in the system and using ffmpeg which I’m too dumb for, I used fre:ac because it included good encoders like FDK.

Anyway normally 224kbps is plenty with AAC, I would never go higher for music for example. For movies there’s the multiple channels thing to consider, might be safe to go a bit higher for 7.1 or more channels, but I have no direct experience.

As I don’t want to reduce the quality of an already lossy codec, I’m instead comparing identical audio tracks of the same release that differ only in their codecs and bitrates. For instance, would a stereo 224kbps AC3 audio track be equivalent to a 128kbps AAC audio track, or is one of the two better than the other?