[MPlayer-users] video scaling doesn't work

[Reimar Döffinger]

On Tue, Feb 11, 2014 at 07:46:00AM -0800, Grant wrote:
> >>> >> I'm using omapfb and video scaling doesn't seem to work.  Does
> >>anyone
> >>> >> know if it should work and if there's anything I can do to get it
> >>> >> working?
> >>> >
> >>> > "omapfb" meaning what?
> >>> > The X11 omapfb driver? You should ask on their list.
> >>> > There is no omapfb vo in MPlayer, that is not supported by us
> >>> > if that's what you use.
> >>> > Either way, upscaling needs special kernel support and userspace
> >>that
> >>> > is updated to make use of this support.
> >>>
> >>> Does mplayer have swscale capabilities like vlc?
> >>
> >>Yes, see options -zoom, -sws and -vf scale.
> >
> > I can only highly recommend to look for a proper solution. Unless you only care about playing 320x480 videos on a screen with not much higher resolution it won't work.
> > There is a very good reason for all that scaling hardware to be in the SoC, ignoring it instead of making it work won't get you far.
> 
> I'm not up to the challenge of programming scaling support into omapfb

Well, someone got it working at some point with X11 and its omapfb
XVideo implementation. So that definitely is possible without
programming, it's just a matter of finding the "magic incantations"
(aka where did they hide the magic combination of programs that worked
on exactly one day).

> so I can either prescale with mencoder/ffmpeg or try to get mplayer to
> scale on the fly.  This works nicely except the video only appears in
> the top 35% of the screen:
> 
> mplayer -vf scale=1360:-1 -fs file.mp4

You'll want something like "-vf scale=1360:-2,expand=aspect=16/9"
but the saying about lipstick and pig applies...
Also I don't know what code you are using, but since this code in the
comment right on top:
http://cgit.openembedded.org/openembedded/plain/recipes/mplayer/files/vo_omapfb.c
explicitly says that _downscaling_ doesn't work that should
mean that upscaling certainly should work.
(Note: there is some ancient code there, so that link is not meant as
endorsement...)