[MPlayer-users] Re: Changing aspect ratio while playing a file

[Sebastian Kaps]

Hi Tony!

> I think Sebastian (the OP) may have misuderstood exactly what
> -monitoraspect does. It doesn't scale the video to *fill* the given
> aspect, it scales it to fill as much of a screen of that shape as
> possible while preserving the original aspect ratio.

Yes, that is how I understand this option.

> So whatever video you play with -monitoraspect=16:9 it will display
> correctly on a 16:9 screen. 4:3 videos will have black borders at the
> sides and 2.35:1 videos will have black borders at the top.

That is correct, but think about it for a second. In order to make a 4:3
video look correct on a 16:9 screen in 16:9 mode, you have to scale it
horizontally by a factor of roughly 0.7. If you wouldn't downscale the
video, it would fill the whole screen.
But when you do, you lose 30% of the horizontal resolution, because the
video is no longer 720 pixels wide (PAL), but 504 pixels. The 16:9 mode
of the TV then stretches these 504 pixels to fit into 720 pixels on the
actual screen.
That's nuts, since all 16:9 TVs I know do have a 4:3 mode where 4:3
videos are displayed in a 4:3 area on the center of the screen (i.e.
black bars left and right). So you won't lose anything if you leave 4:3
videos unscaled and switch the TV into 4:3 mode.

-- 
Ciao, Sebastian