Alpha Channel

[D1gits]

Hi there!

Have played around for some weeks now with Magic and Resolume Arena. It works great. Now I just want to be able to take the reactive elements I created, and play in between layers in Resolume. I tried to use a Green polygon as bottom layer, to chroma key the "background" but it did not work. The effekt Auto mask did not do it either...

Any chance to get it working with Syphon and an Alfa Channel? Or is there another work around?

[dj0le]

Hey D1gits

Magic and Resolume work very well together, but they can be a bit confusing at first. I took a few screen shots that show some different examples. Hopefully, this will help you do what you need to do.

It sounds like you want the Magic content to play 'on top' of the vj clips or whatever you are running in Arena. In that case, just make sure your spout receiver is on the top layer and the clips are underneath. Anything sent from magic that doesn't take up the whole output window will already have alpha. Here is an example of Eric's 3d Spectrum running on top of a VJ clip in Resolume:

Screen2.jpg (59.81 KiB) Viewed 3850 times

Notice, that both the spout receiver layer and the resolume vj clip are both set to 100% opacity and both show up. So in your sketches, just delete any layer that covers the entire background and you will see your objects fine.

On the other hand, maybe you are modding a shader or video file in Magic that has no alpha. If that is the case, and you are sending a full window, then you won't see anything underneath. There are 2 ways to move forward:

You can set the layer opacity of the spout receiver to 50% or so and you will see both layers:

Screen6.jpg (79.65 KiB) Viewed 3850 times

I'm not a big fan of this method, but it can be used if you mess with the blend properties and opacity and you use clips that work well together.

Or, you can use the "Auto Mask" effect in Resolume. It will take out all the black pixels in the layer. Here is an example of a video file from Magic with no alpha running on top of the vj clip in Arena:

Screen4.jpg (95.71 KiB) Viewed 3850 times

I'm not sure why it didn't work on your specific sketch, but there are a few things you have to setup for it to be correct.

1. Place the spout layer above the layer you are using for the clips in Arena
2. Drag the Auto Mask effect directly onto the Spout Receiver
3. Change the blend mode from 'add' to 'multiply' on the Spout Receiver layer
4. Then you can mess with the opacity and contrast until you get it exactly the way you want

You can also use auto mask to take out the white pixels instead of the black ones, but it's a little more involved.

hope this helps

[D1gits]

Thanks a LOT dj0le!

In the end the first picture with the "Add" highlighted made the whole difference. I have set my Arena Video settings to "disable global effects a% blend modes". Just to have my machine run a bit faster. But when this checkbox is filled you can't use Alfa channels!

Uncheck this box if the Alfa Channel is wanted

Skärmavbild 2016-03-15 kl. 15.40.34.png (60.78 KiB) Viewed 3841 times

Great to know : )