Try doing that a couple times in a row, recording the audio and video. Can you do it the same way twice, with a measure of "same-ness" that can be trivially co

Try doing that a couple times in a row, recording the audio and video. Can you do it the same way twice, with a measure of "same-ness" that can be trivially computed? No, humans cannot do that. Error rate in the context of computing does not need to mean invalid, just different. Our astonishingly high abilities to compensate for variations in input data do not result from an ability to produce output data repeatably.