Width and height are rounded to multiples of 2 and 4 for certain optimizations.
The only thing I know about resolutions better than others with h.264 is that ideally in good resolutions the width and height should be divisible by 16 (or close to it), but that's not even the case with 1080p. : )
Are these optimizations, the rounding to multiples of 2 and 4, for scaling filters? Where else could there be a gain in performance or quality?
The funny thing is that according to my measurements, a twitch stream in theater mode on a 1080p screen is 1580x889, not even 16:9...
Twitch wants 16:9 but display something else x) Stretching in the player... stretching >> in >> the player... i'm sad now :(
1584x891 would have been the closest 16:9 resolution to theater mode on a 1080p screen... :(
:( 1600x900 is about 2% bigger than 1584x891, 2% of 6000 kb/s is 120 kb/s, it's already a big - potential - loss. :(
sorry for the bad english and emojis abuse lul : )