Video with alpha layer creating strange black artifacts?

[philjms]

I have a video texture playing with an alphaMap. It looks fine, but for the fact that I’m getting strange black artifacts during playback. Does anyone know what the problem is, or how I might fix it? I’m guessing the alpha layer might be moving slower than the video?

Example here:

[Mugen87]

Is it possible to create a fiddle that shows the visual error? This will be a great help for debugging!