Guess it depends on the frame rate and sample rate?
If sample rate is 48k and frame rate is 24fps that works out at 2000 a frame (i think!!) lol It's late and I'm quite tired so forgive me if I'm off ;)
Hope that helps
each frame audio depends on a video if a video is of 96 / 24 then it would be 96000 / 24 you will get a frame's sample so it would be 4000 samples per frame and if it is 48/24 it would be 2000 samples per frame :D