Forum Discussion
Apply Multiply blend mode to video?
You could try Davinci Resolve. Even the free version provides access to the chroma-key effect with control over strength. It can also be applied as multiple filters which might give better results on your video.
If you remove the black but it leaves flames that are too transparent, you could always re-render an output video by stacking multiple copies of the your keyed version in Resolve or Premiere, making them appear more opaque.
Possibly with some JS. Any chance you can share the media files so I could experiment?
OK. If I understand, you have an image of a room and a video of flames rendered over a solid black background. Essentially, you want the black (and potentially, the flames) made transparent so the room is visible. Correct?
You might be able to do something like that on the fly with svg filters and masking. I made a post about that a little while ago that demostrated some potential uses, including some video elements. You could get some ideas there.
Another, probably easier approach would be to have your flame video re-rendered as a transparent video (either from go, or chroma-key the black, which would definitely leave the flames somewhat transparent). Since SL doesn't support transparent video directly, you could swap out the sources at runtime, replacing the original with the transparent version. Overlay that onto your room image. I made another post about that here.
If I get a chance to mock-up something simple this weekend with some stock media, I'll post it here.
Hi, Nathan;
In your first paragraph, you captured it beautifully! I think you're right...these flames should be re-rendered. These flames were done for us and I don't have access to the work files used to create the flames (in After Effects.)
Premiere Pro does have a few tools designed for keying out user-selected colors, but the results for this particular clip are...heinous. I think it's because the flames are so wispy and ever-changing. Rather than keying out the black, it ate into the flames in a chunky, aliased way.
You could try Davinci Resolve. Even the free version provides access to the chroma-key effect with control over strength. It can also be applied as multiple filters which might give better results on your video.
If you remove the black but it leaves flames that are too transparent, you could always re-render an output video by stacking multiple copies of the your keyed version in Resolve or Premiere, making them appear more opaque.
Excellent ideas, Nathan. I thank you for them!
Have a look at this example project. It uses an SVG filter to key out the black in the video on the fly. Starts with the original video. Click the button to key out the black. I think it works quite well.
https://360.articulate.com/review/content/d71dcc95-f970-4a66-ac09-2353d62d6265/review
Essentially, assemble your scene, with the video over the room image. Set a variable called tag with the accesibility text from the video in the timeline. Run the script.
It looks for the video, builds a custom SVG container that includes the filter, inserts the original video, and then inserts the SVG where the video used to be. The filter is applied and the black is now transparent.
Pretty sraightforward.
You can consult the reference links (top of script) and tweak the filter settings if desired. Try increasing the value 3 in the following line to something like 15 to see the difference in the flames.
filterName.setAttribute("values", "1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 3 -1 -1 0 0");
