Alpha Transitions

Transitions / track mattes should be baked into the alpha channel of your delivered videos. There are some exceptions to this rule where you should deliver the track mattes to be composited in the playback server:

When you want to alpha animate out of of a looping video on a cue, you should deliver a track matte. While you could bake the alpha out into a looping video, it would only fire at the end of a loop. So if your loop is five seconds, it is possible that the alpha animate out would not be seen on stage for five seconds beyond when the cue is fired. Track mattes are better because we can fire track mattes at any point, regardless of our position in a looping video.

This is an efficient way of delivering videos if you are uncertain of the alpha in/out effect you want to use, as we only have to receive one copy of the background video, and can easily swap between multiple luma mattes options.

Delivering Track Mattes

Content can be transitioned in or transitioned out using either alpha or luma track mattes. However, luma track mattes are the most flexible, and should be chosen over alpha mattes wherever practicable.

The playback engine cannot play videos in reverse, and track mattes that are reused for both animating in and animating out a video should be delivered twice, once playing forward, and once playing reversed.

Luma Matte: Black is 0% video opacity and white is 100% video opacity.

Examples of Luma Mattes: