10 different transition mattes created using an ink bleed effect, with both sharp and soft edges (20 files in total).
Each movie is 10 seconds long so you can have a long transition, or time remap the files to make them shorter for quicker transitions.
1920×1080, 29.97fps
Quicktime H264
Movies DO NOT have an alpha channel, so use them as luma mattes, not alpha mattes.