beside what has been mentioned here already regarding really old films theres also the same effect when you watch TV recordings especially older stuff.
the reason why TV recordings are faster than they should be is that they play movies at 110% speed so they have more time to play ads.
on a standard 90 minute movie this little trick saves them 9 minutes which is just enough for an entire ad segment.
this can be more noticeable in older recordings because they would sometimes play back the movies even faster to test out the limit when people would complain.
It has to do with frames per second. There weren’t any standards back then and the numbers of frames per second were less and in many cases, variable because they were filed by a hand cranked camera. Because of this, films varied from around 12 fps to 16 fps.
When sound was added, they standardized on 24 fps. Since things were now mechanically locked to 24 fps, when playing older film on the same this equipment, everything is sped up by 8 to 12 fps making everything move faster.
It it possible to adjust the fps to make them look more natural if wanted but it’s generally not worth the extra effort.
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