[FFmpeg-user] why reducing the resolution a percentage doesn't reduce the video the same proportion?

[Bouke / edit 'B]

> On 14 Mar 2023, at 14:03, Natalia Molinero Mingorance <eng.nataliamolinero at gmail.com> wrote:
> 
> what do you mean by " Why is the output size important if you use -preset
> ultrafast?  “

That will mean quick and dirty encoding, at the cost of a higher bitrate.
-preset slow will make the file significant smaller, at the cost of more processing time / cpu use.
(And thus energy use, but if you stream too large files a gazillion times, you might want to invest in high quality encoding instead of quick ’n dirty.)
It’s a ‘would you like to be bitten by the cat or by the dog’ situation.

Bouke