Improved chroma key quality and auto-detection

We've made some notable improvements to our chroma keying tech – you will find the technical details in this post. The updates can be found in version 1.6.9.x or higher.

Improved chroma keying algorithm

We've improved how the chroma key works with colors. Here's what it was like before:



Now:



And here's how borders looked in older versions:



And now:



Improved auto-detection

Now the background color is detected more precisely. There are two new parameters:

  • detect.borders=15%
  • detect.similarity=0.3

Please don't ask me how they work. :)

Other changes in parameters


The "gpu_mode" parameter now has settings "auto", "true" or "false" – instead of "0", "1" and "2" previously. Please check your code. The old value "0" means CPU mode.

In order for higher performance in MMixer, you must specify "output.argb=false". In this case the output of the chroma key engine is an HDYC image with mask – so MMixer does not have to convert from ARGB to HDYC and extract the mask from ARGB. Obviously, if you're using the mixer in ARGB mode (such as in keying mode), you should not use this setting.

Alternatively, you can specify these parameters in the following registry key:

HKEY_CURRENT_USER\Software\Medialooks\MChromaKey