Hypothetically it could compress down to a few bytes. Just color and duration.
Given the number of videos that are a single static image plus audio surely YouTube has built in a special case for them.
Given the number of videos that are a single static image plus audio surely YouTube has built in a special case for them.
Edit: Tried using yt-dl on a 24 hour white screen video, it is 130 MB for the 'highest quality'. 10 hours of white noise it 1.55GB.
If you encoded in mpeg I'm sure you would dramatically reduce the file size, but not as magically as you would think. It will still store a new white iframe every 16 frames by default, though many encoders will let you specify an alternative.
In theory I guess YouTube could spend n-times as much processing to encode each video in n formats to find the smallest for that particular video and serve that encoding, even doing so after a video reaches x views to cut out yy% of wasted computation, but then they would have to support n codecs on m devices instead of just 1.
I’m on mobile but I will check that later using yt-dlp and ffmpeg to list the I-frames.