[MPlayer-dev-eng] [PATCH] dsize negative scale values

[Trent Piepho]

On Mon, 4 Jul 2005, Oded Shimon wrote:
> On Mon, Jul 04, 2005 at 12:22:57AM -0700, Trent Piepho wrote:
> > How about....
> > 
> > dsize=x:y:aspect_method
> > 
> > x or y = 0, as if you had specified the original size
> > aspect_method = 0 Preserve aspect, treat x:y as a minimum size (default)
> .. as in, upscale
> > aspect_method = 1 Preserve aspect, treat x:y as a maximum size
> as in, downscale...
> > apsect_method = 2 Ignore the aspect ratio, just use x:y
> 
> If you haven't noticed, what you just described is (almost) EXACTLY the 
> same as what I've done!! Only described differently and using different 
> numbers...

Well, you have a lot more numbers.  It's not clear to me how x = -2 and
aspect_method = 3 are supposed to interact.

> > If you want to:
> > Upscale to the correct aspect, dsize=0:0:0
> > Downscale to the correct aspect, dsize=0:0:1
> > Fit in 800x600 with the correct aspect, dsize=800:600:1
> > Just horizontally scale to get the correct aspect, dsize=9999:0:1
> > Just use 640x480 no matter what, dsize=640:480:2
> > 
> > Is there any reasonable thing that a person would want to do that you can't
> > easily do this way?
> 
> You forgot only one thing - there are TWO different kinds of aspects. 
> original aspect and display aspect. This is the only "complexity" added, 

Why is it necessary?  The pixel aspect ratio of a NTSC SVCD is 15:11, which
gives it a picture aspect ratio near 4:3.  If you wanted to pretend a SVCD had
square 1:1 pixels, which they don't, then the picture aspect ratio would be
1:1.  But why would you ever want to do that?  What you'd be asking is,
"pretend the pixels are an aspect they're not, and then preserve this pretend
aspect." It just doesn't seem a reasonable thing to do.  Can anyone tell me,
why you would want to do this?