Procedural Compositing with Batch > Batch: Node Reference >
Logic Op Node

The Logic Op node accepts a front, back, and matte clip.

Logical Operations box
  Select the logical operation you want to use to combine the source images.
Swap Inputs button
  Enable to switch the ordering of the Front and Back inputs.
Transparency field
  Displays the percentage of the back clip that is used in the operation.
Clamp Render box
  Select a clamping option for colour and luminance values on output in the 16-bit floating point processing pipeline.

The Logic Op node processes missing media in clips set to No Media based on the input tab it is connected to.

Input | Result
--- | ---
Front | No media
Back | Black frames
Matte | White frames

See Using Logical Operations.