[MPlayer-dev-eng] aspect ratio stuff

[Felix Buenemann]

On Tuesday, 2. October 2001 01:38, Arpi wrote:
> Hi,
>
> I've changed it a bit.
>
> Reason: -aspect 1.0 (or -aspect 1:1) actually means scaling!
> It means scaling to square, when width==height. (try it...)
> So it shouldn't be ignored at prescaling!
>
> (-aspect sets the frame aspect ratio (ratio of width/height), not the
> pixel's aspect ratio (width/height of a single pixel on the monitor))
>
> So I've changed it, now 0.0 means undefined aspect, if aspect==0
> (actually if aspect<0.01 to handle negative and rounding) then
> no prescaling is applied.
>
yes, it makes more sense.

> Also added -noaspect switch to override possible default value in cfgfile.
>
ok
> We should also handle monitor (pixel) aspect ratio. Now it's assumed to be
> 1.0, but for 16:9 TV/monitor it isn't 1.0, and neither for 1280x1024 (it is
> 1.0 for 1280x960 AFAIK, and it's 0.82 for 320x200 IIRW).
> We should allow user to specify pixel aspect directly, or specify the
> aspect ratio of the monitor dimensions (4:3 or 16:9 or other) and calculate
> pixel aspect using monitor aspect ratio and X resolution.
> Later (monitor aspect) is more usefull, because it is constant if user
> doesn't change tv/monitor -> can be put into config file.
> Pixel aspect depends on curent X resolution too.
>
> For example:
> my 15" monitor is 285mm * 215mm  (+-5mm)
> in 1024x768, each pixel is (285/1024) mm * (215/768) mm == 0.278 * 0.280
> so aspect is 0.278/0.280=0.994 ~= 1.0
>
> For 1280x1024, it's 0.223 : 0.21 = 1.062
> For 1280x960:  0.223 : 0.224 = 0.995 ~= 1.0
> For 320x200:   0.89 : 1.075 = 0.828
>
yes, of course, this is my next step (I told you I'd add -displayaspect or 
maybe I should better call it -monitoraspect with it's default being 4:3)
>
> A'rpi / Astral & ESP-team

-- 
Best Regards,
	Atmos
____________________________________________
- MPlayer Developer - http://mplayerhq.hu/ -
____________________________________________
Escape the Gates of Hell.
	- Use Linux.