In the past I’ve chosen I’ve often kept AC3 audio tracks thinking that their substantially higher bitrates made them better than the AAC tracks I compared them to. As I’ve since learned that AAC can be comparable to AC3 at a substantially lower bitrate, to have a means of comparing the two codecs, what would the AAC-equivalent bitrates be for 224kbps and 640kbps AC3?
Sorry I edited my other reply heavily because I noticed later that you were interested in some exact bitrate numbers… I don’t know enough about AC3 to know an equivalent number, all I can say is those numbers I’ve written for opus and AAC are in my experience enough to enjoy any movie.