YouTube audio quality at the HD setting (720p/1080p) is 128kbps AAC, which is close to being considered "audibly transparent" (I believe for AAC the bitrate is a little higher for that - 192kbps?).
128 kbps? Audibly transparent?
Only on the promotional materials for MP3 players that came out at the beginning of the century (back when capacity was still measured in megabytes on most of them). That whole "64 kbps is FM quality, 128 is CD quality" was a huge joke -- even then.