alpha key on panasonic av-hs450 multiformat live switcher

[Walter Soyka]

[simon zehentner] “until now i always worked with chroma keys for live production. but now i have to set up a key for graphics with alpha channel and i don’t really now where to beginn. so if someone could tell me with which key i can mask pictures with alpha channel in general and maybe even on a panasonic switcher in particular i would be very thankfull.”

You can self-key based on luminance (this is called a luma key) just as you do with chroma-keying. This is usually used to knock a graphic off a pure black background, but has a very limited range of transparency.

If you have separate key and fill sources, you can use a linear key. This uses the luminance of the key source to control the transparency of the fill source. Areas of the fill where the key is white are kept; areas of the fill where the key is black are eliminated; shades of gray in between allow partial transparency.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
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[Chuck Pullen]

I’ve just started working with a Blackmagic Decklink card with key/fill output. It eats up two very valuable inputs on the HS450A, but it does the job very well.

[Danny Nguyen]

hi Chuck !
i new to av-hs450n and new to all the lowerthird graphic for live. can you hep me on setting up ? i doing a live show really soon. i dont know how to set up external key t the hs450n as dsk. if i use the internal key on the hs450n the graphic easily get hole in it