[MPlayer-users] No vf_ commands for -slave?

[Dave Wood]

On 08/06/20 14:04,
Kevan Hashemi <hashemi at opensourceinstruments.com> put forth the proposition:
> Dear Reimar,
>
> Thanks for your attention.
>
> > I don't know what you're trying, but mostly I'd say that the result wouldn't make any sense.
>
> I expect that I'm using the word "scaling" wrong. When the user changes the size of the window, the video display changes size also. I don't know what that's called. Maybe it's "zoom", because that's the command I use to have the same effect. I'd like to be able to tell the slave to change the value of "zoom".
>
> > If you want the window a different size you can just make the window a different size
>
> I can't as the process sending commands into the slave MPlayer. So far as I know, only the user of my program can change the window size.
>
> > Similar for expand.
>
> As above: I doubt I know what you mean by "expand".

Just to make clearer what I would like to do and what is meant by
`expand', I have a few different profiles that use -vf-pre:

[win-1]
vf-pre=scale=640:-2

[win-2]
vf-pre=scale=768:-2

[win-3]
vf-pre=scale=800:-2

... etc.

In [general] I have:

vf=expand=-8:-40:4:35,scale

The result is a profile for each size with `expand' in [general]
making black borders.  The top border is big enough to hold the OSD
for the time code (that depends on the font scale too though).

I'd like to be able to change the `vf' setting via the fifo, to
(hopefully) switch window sizes on-the-fly.

IOW something like the af_switch, but for video.  From slave.txt:

af_switch <filter_arguments_list> (comma separated list of audio
filters with parameters)
(experimental) Remove all the audio filters and replace them with the
given list.

It looks like starting a new slave with the relevant settings (or
profile) is the only way that would work, but I can see that starting
a new slave from the parent, and then exiting the parent process
could be a problem though.

--
Dave