It's just an idee.

Can we have a selector in full screen to select the size of screen.

I have a 16/10 screen. I have select 'Letter box 16/10 display'.
But when I see a 4/3 program, I can't read the subtitle. I select 'Letter box 4/3 display' to see the program.
After, I watch a 16/9 movie, I have vertical and horizontal black band. I select 'Letter box 16/10 display'.

In the right clic menu... and in controls key.

PS: Thanks to read my bad english.

Changing aspect ratio on runtime, controlled by transmitted content, may also depend on the codec in use, e.g. on it's internal settings, and your renderer.
So details rule, as always...

Hum... maybe, I wasn't understandable.

I'have no problem to change the aspect ratio.

My question was : "Can we have a shortcut to change these aspect ratio ?".

Maybe, I have not understand... Sorry for the inconvenience.

OK, got it now.

This would be a GUI control to toggle AR then.
For example, this may make sense, if a station sends a false AR flag, or to inflate 4:3 letterboxed 16:9 material transmissions and alike.
Should perhaps fall back to default, if the transmission flag changes, and on channel change.
And yes, if in full screen, a context menue item for this would be good to have.
And position of OSD subs should be moved then.

Wonder if Prog would try to implement this occasionally...

Ok thanks.