[MEncoder-users] -vo null -vf cropdetect => "incompatible video_out".... Huh?

[Joe Emenaker]

I'm trying to do crop-detection very quickly, so I'm executing something 
like this:

    mplayer -benchmark -nosound -ao null -vo null -vf cropdetect -frames 
1000 dvd://

However, lately, I'm now getting the following error when I try this:

    "The selected video_out device is incompatible with this codec"

Removing *either* the "-vo null" or the "-vf cropdetect" makes the 
problem go away, so, for now, I've removed the "-vo null" and just get 
to see a section of the movie zooming by real fast.

But still.... WTF? Is it because the null video_out doesn't even decode 
the video an, hence, the cropdetect doesn't have any material to look 
for black bars on? If that's the case, is there some video_out that 
*does* decode the video but doesn't show it to me?

- Joe