[MPlayer-users] How To: best way to rescale

[Oliver Seitz]

> There is a native resolution inside the file. For example, I like to  
> encode
> my files all in 720x480 *it's a arbitrary number, I could choose 600*600
> just as well). Then there is something in the header that says  
> (depending on
> container) that contains information about the display aspect ratio  
> (which
> translates to the rectangular shape of a pixel) and/or output size, width
> and length.
>
> Of course, it depends on the player whether that will actually be  
> observed.
> As an example: I use XBMC which has its own player. This player will  
> observe
> all these things, it actually allows you to switch between various
> interpretations of this information. There are hardware players which  
> will
> not observe this information although most players that play Matroska  
> format
> are pretty compliant. Most players that play AVI files will ignore the
> aspect ratio placed into it by mplayer. Mplayer itself will observe
> information from Matroska.
>
> I guess in the end it depends on what soft/hardware plays it back.  
> Again, if
> you use mplayer you can simply tell it how you want it rendered through
> command line switches (or resizing the window if you can do this in you
> particular application).

Thanks for the explanation. I can add for MPlayer that when I play avi  
files with no special options, it will give the aspect ratio in the header  
on to the video out device. So e.g. -vo xv will play the aspect of the  
header, as this -vo ca scale by itsself. -vo x11 will play the aspect of  
the frames, as x11 can not scale.

In this case the problem was a hardware player which refuses to play  
resolutions greater than 800x600. I really doubt that such a limitation is  
just an arbitrary constraint with no cause. So I dare to question if that  
hardware player will play a, say, 1024x768 file when only the header  
commands to rescale to 800x600.

Greets,
Kiste