Chroma key

  • Thread starter Thread starter markit
  • Start date Start date
M

markit

Where mistake i?
<TransitionsAndEffects Version="1.0">
<Transitions>
<TransitionDLL guid="{C5B19592-145E-11D3-9F04-
006008039E37}">
<Transition name="cromawhite" iconid="91">
<Param name="KeyType" value="0" />
<Param name="Invert" value="False" />
<Param name="RGB" value="0xffffff" />
<Param name="Similary" value="30" />
</Transition>
</TransitionDLL>
</Transitions>
</TransitionsAndEffects>
This transition works only with KeyType = 1
Why?

Thanks
 
What resource does your xml file reference? Does it use
one of the standard transitions that come with MM2, one of
the Pixelan transitions, or a custom dll?

Ken
 
I have a partial solution.

First, some general observations about custom effects and
transitions in general:

1. There are many options that just don't seem to work.

2. I have noticed a difference in the behavior of some
effects and transitions depending on the order in which I
list the properties. This is a shame because, in general,
the properties are listed in alphabetic order. When trying
to trouble shoot an effect or transition, I would
recommend eliminating almost all of the properties,
accepting the defaults. Then add them back in, changing
the order, and see if it makes a difference.

I spent some time trying to trouble shoot this custom
transition. The documentation I found is on the MSDN
website (http://msdn.microsoft.com/library/default.asp?
url=/library/en-
us/directx9_c/directx/htm/keytransition.asp). I could not
get the Invert property to work, however If I included it
in the wrong order, the entire transition would not work.
I recommend leaving it out. I also could not get the
Similarity property to work correctly. If I gave it a
value other than 0 (exact matches) or 100 (all colors
transparent) then I got a lot of static with both pictures
faintly distinguishable through the static. With those two
properties removed, I did get a transition to work with a
KeyType of 0. The default for Similarity is apparently 0.
this means that only pixels with color values exactly
equal to the RGB property will be transparent. This will
almost never occur with live video. You could use this
transition with pictures (or even video) created in a
graphic program where you can define specific regions as a
flat color (e.i. 0x0000FF). An example would be to use
this transition to create more advanced title overlays.

The Nonred key (KeyType = 1) also has some problems, but
appears to be a better option for video over video
transitions.

The Luminance key (KeyType = 2) appears to grow the affect
from completely opaque to completely transparent for
pixels matching the Luminance value. I could not find this
behavior in the documentation.

I have not looked at the Alpha or Hue keys yet so I can't
comment on them.

I hope this helps.

Let me know if you get the Similarity property to work. It
would be very handy!

Ken
 
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