It means trying to use lossless is pointless because it still needs to be converted down to 256k AAC for the APM to work. However in reality a 256k AAC will have no difference that you’d be able to hear compared to lossless.What I mean is how does it make the sound quality worse? It’s still encoding and decoding AAC, so how do the other processes affect it?
Using the cable just adds an extra digital to analog to digital conversion to the process!