[mythtv] [PATCH]Black border filter

[Cedric Tefft]

Kristof Pelckmans wrote:

>Here is an implementation for an automatic aspect ratio detection filter.
>
>Kristof
>
>  
>
Sounds like a good idea.   Unfortunately, I wasn't able to get it do to 
anything.  I was somewhat confused by the explanation of the parameters...

>III. How to use
>
>example :
>blackborder=0:70:76:430:18:20,blackborder=0:40:46:490:18:20
>
>The first filter detects a 16:9 video stream in a 4:3 capture stream
>and the second is for a 14:9 video stream in a 4:3 capture stream.
>
>The different parameters :
>1) 0 for horizontal, 1 for vertical (not implemented)
>2) start line
>3) end line
>4) 'black' pixel threshold : all pixels below this threshold will be
>considered as black
>5) 'black' line threshold : minimum number of black pixels that have to be
>present to consider a line 'black'
>
>  
>

There are six parameters in the example, but only five are described, so 
after start line, I'm kinda guessing...  Could you maybe clarify which 
parameter is missing from your explanation and what it's for?

w/rt what the 'black pixel threshold' parameter:  This could use some 
clarification.  What's the context?  What's the range?  For example, is 
this an integer from 0 to 100, and if so, what does 0 mean, and what 
does 100 mean?

w/rt the 'black line threshold', wouldn't it be better to express this 
as a percentage rather than a pixel count?  By using a fixed number of 
pixels, you're tuning the filter for use with one particular horizontal 
resolution, whereas if you use a percentage, the filter adapts itself 
automatically to the resolution of the source material.

- Cedric