[MPlayer-dev-eng] Passing parameters to video/audio output drivers

Deron Kazmaier deron at pagestream.org
Mon Sep 19 21:23:37 CEST 2011

I've been tinkering with the DeckLink patch submitted in August of 2009 
patch url 
and have it working for the most part. I could use some pointers on how 
best to solve a few problems within the proper mplayer framework.

First, as I understand it the video output mode is selected using the 
width and height based on the width and height of the video data. It 
will fail if the width and height do not match. I can select the next 
size up, but is there someway for the decklink driver to cause a 
scale/crop/pad for mplayer etal to fill out the data or does it need to 
do that itself? I know the user can scale it, but is it recommended to 
do this automatically since it is required?

Second, that same code does not try and match the fps. It was just 
picking the first fps option that matched the width/height. Can I get 
the fps of the video data in the config call of the video driver? Again, 
if it does not match an available output, can I request it be scaled up?

Lastly (well for the video driver for now), I need to select from 
multiple output devices. I happen to have 2, but each device can have 
multiple outputs itself. What is the proper way to pass parameters like 
this to the driver?

If some existing drivers do these things, I'm happy to go look there, 
just which drivers to go look at? I'm not trying to get anyone else to 
do any heavy lifting, but I'm overwhelmed with the amount of unfamiliar 
code and would like to see this patch conforming to mplayer standards 
and included.



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