Video Remixer: Find Break Frame in Scene Splitter

[jhogsett]

Adds Find Next Break buttons to the Video Remixer Scene Splitter

• scans through the frames to find a mostly all-black frame
• works in forward and reverse directions
• samples a configurable subset of pixels to speed up the search

This is useful when trimming content around opening and ending credits, or when manually splitting a scene on natural breaks.

New config.yaml settings

remixer_settings:
  find_break_stride: 128  # only check every this many pixels in the image to speed up the check
  find_break_threshold: 1 # the average lightness of the sampled pixels must be this value or lower to be a break frame (0-255)
  skip_break_threshold: 3 # near-break frames are skipped on repeated use if at or below this value