CD quality audio, in effect, has frames which are only four bytes long (16-bit samples, two channels) but which play back at 44.1kHz. This only gives you 22 microseconds per frame! Of course, the frames are miniscule, but if you miss even one, odds are that the user will hear it. If you did something terrible like take a disk interrupt that took five milliseconds to process, you will hear an ear-rending glitch in the output audio. By contrast, you can drop an entire 17ms frame in 60fps video and it’s usually pretty hard to notice.