(click to play)

Here’s a video tutorial on using color channels in Photoshop to speed up the process of making masks. When selecting layers, remember:

1. Cmd-click on a regular layer makes a selection along the outer edge.

2. Cmd-click on a mask selects everything in the white parts of the grayscale image.

The iPhone screen is a nonstandard size, wider than 4:3 but slightly less wide than 16:9. It’s 480×320, which works out to about 14:9.

The phone scales everything to fit when playing video, so it’ll letterbox a 16:9 movie, which will be pretty gentle.

For further reading, see here and here.