As I understand it the best quality Bluetooth audio codec in iOS is AAC but it maxes-out at about 250kbs as opposed to 256kbs. Does that mean that if my local files are encoded at 256kbs the iOS audio stack will decode my AAC 256kbs files and then re-encode them to go over the Bluetooth link? If yes then obviously going with ALAC would avoid any decode/re-encode quality loss but I was a bit underwhelmed by the iPhone 12 announcement so I don’t want to jump to the 512GB model right now to get space to do that. This year I want to just use the doubling of the base iPhone storage level (64GB -> 128GB for the Pro Max) to upgrade my current 128kbs CBR AAC encoding to something like 256kbs AAC (CBR or VBR to be decided).
So what do I do to get maximum quality? If I pitch my AAC encoding a bit below the Bluetooth AAC codec‘s maximum rate will that avoid any decode/re-encode operation and will my locally stored AAC files simply be passed as-is over the Bluetooth connection or is there always a decode then re-encode operation whatever the file format (as mentioned except for ALAC of course where the decode is a lossless decompress so doesn’t affect quality)?
Finally, any advice on CBR vs VBR? I’m not sure whether, if there is any way to avoid a decode/re-encode cycle, going VBR might mess up a simple pass through and push the audio stack into a decode/re-encode.
So what do I do to get maximum quality? If I pitch my AAC encoding a bit below the Bluetooth AAC codec‘s maximum rate will that avoid any decode/re-encode operation and will my locally stored AAC files simply be passed as-is over the Bluetooth connection or is there always a decode then re-encode operation whatever the file format (as mentioned except for ALAC of course where the decode is a lossless decompress so doesn’t affect quality)?
Finally, any advice on CBR vs VBR? I’m not sure whether, if there is any way to avoid a decode/re-encode cycle, going VBR might mess up a simple pass through and push the audio stack into a decode/re-encode.