This macro iterates through a directory of subdirectories each which contains three directories of timelapse images.

master_dir
  timepoint00
    Ph (each contains a sequence of individual files)
    Ch2
    Ch4
  timepoint01
    Ph
    Ch2
    Ch4
  timepoint02
    Ph
    Ch2
    Ch4

The user chooses the master_dir.

Each subdirectory of individual images is opened into a stack, processed, and saved as AVI.

process_nested_directories_macro_v100.txt