module Ffmprb

  class Process

    class Input

      # TODO? speed-up/slow-down
      def pace(ratio)
        Paced.new self, pace: ratio
      end

      class Paced < ChainBase

        attr_reader :ratio

        def initialize(unfiltered, pace:)
          super unfiltered
          @ratio = pace
        end

        def filters_for(lbl, video:, audio:)

          # Pacing

          lbl_aux = "pc#{lbl}"
          super(lbl_aux, video: video, audio: audio) +
            [
              *((video && channel?(:video))? Filter.setpts(@ratio, "#{lbl_aux}:v", "#{lbl}:v"): nil),
              *((audio && channel?(:audio))? Filter.atempo(@ratio, "#{lbl_aux}:a", "#{lbl}:a"): nil)
            ]
        end
      end
    end
  end
end