SEE https://github.com/InsanityRadio/automix ; Automatic Vision Mixer. Licensed under CC-BY-NC - contact me for commercial opportunities.

switch.rb

#!/bin/env ruby

require 'rjoystick'
require 'atem'
require 'mysql2'

$AUDIO_THRESHOLD = 858803 * 2
$IP = "10.0.0.1"
$JOYSTICK = "/dev/input/js0"
# CREATE TABLE link_history (`id` int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT, `start_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, `end_date` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00');
$DATABASE = Mysql2::Client.new(:host => '10.0.0.0', :username => 'root', :password => 'toor', :databae => 'mic', :reconnect => true)

class Inputs
	def initialize mapping, mixer
		@mapping = mapping
		@mixer = mixer
		@k = Rjoystick::Device.new($JOYSTICK)
		Thread.new do
			loop do
				begin
					e = @k.event
					handle_event e
				rescue
					STDERR.puts "Error in Joystick thread"
					STDERR.p $!
					@k.close rescue nil
					@k = Rjoystick::Device.new($JOYSTICK)
				end
			end
		end

	end
	def handle_event e
		return unless e.type == Rjoystick::Event::JSBUTTON
		return unless @mapping[e.number] != nil
		e.value == 1 ? @mixer.enable(@mapping[e.number]) : @mixer.disable(@mapping[e.number])
	end
end

class VisionMixer

	attr_accessor :close, :wide

	def initialize ip, close, wide, slate

		@ip = ip
		@close = close
		@wide = wide
		@break = true
		@current_camera = wide[0]

		connect!

		@close.map! { | w | @atem.inputs[w] }
		@wide.map! { | w | @atem.inputs[w] }

		@slate = @atem.inputs[slate]

	end
	def loop!
		sleep 0
		loop do

			select_camera
			sleep 0
			# Make the camera live then start immediately gathering data again
			live_camera
			reset_peaks
			sleep 2

		end

	end

	def connect!

		@atem = ATEM.connect(@ip)
		@atem.use_audio_levels = true
		@atem.inputs[@current_camera].program

	end
	
	def enable camera
		debug "Enabling #{camera}"
		camera = @atem.inputs[camera]
		@close << camera unless @close.include? camera
		reload
	end

	def reload
		old_break = @break
		@break = @close.length == 0
		return unless old_break != @break
		# Store it in the database - if there's now a break, end the current link. Otherwise, open one. 
		begin
			if @break
				$DATABASE.query "UPDATE link_history SET end_date = CURRENT_TIMESTAMP() WHERE end_date = 0;"
			else
				$DATABASE.query "INSERT INTO link_history (start_date, end_date) VALUES (CURRENT_TIMESTAMP(), 0);"
			end
		rescue
			STDERR.puts "SQL Update failed!"
			STDERR.send :p, $!
		end
		select_camera and live_camera
	end

	def disable camera
		debug "Disabling #{camera}"
		camera = @atem.inputs[camera]
		@close.delete camera
		reload
	end

	def select_camera

		begin


			@new_camera = (@wide + @close).sample

			if @break

				@new_camera = @slate
				raise "Done"

			end
			
			if @wide.include? @current_camera

				if Random.rand(3) == 0
					@new_camera = @wide.sample
					raise "Done"
				end

				highest = [nil, $AUDIO_THRESHOLD]
				p @close.length
				@close.each do | cam |

					maxim = [cam.audio.levels[:left_peak], cam.audio.levels[:right_peak]].max
					highest = [cam, maxim] if maxim > highest[1]

				end

				if highest[0] != nil

					p highest
					@new_camera = highest[0]
					raise "Done"

				end

			end

			if @close.include? @current_camera

				if Random.rand(3) == 0
					@new_camera = @wide.sample
					raise "Done"
				end

				@new_camera = @close.sample
				raise "Done"

			end

			@new_camera = @wide.sample

		rescue
			p $!
			p $?
		end

		debug "Selected camera #{@new_camera.name}"

		@new_camera.preview unless @current_camera == @new_camera

	end

	def live_camera

		debug "#{@new_camera.name} is live"

		@new_camera.program unless @current_camera == @new_camera
		@current_camera = @new_camera

	end

	def reset_peaks

		@atem.reset_audio_peaks

	end

	private
	def info message

		puts "[ INFO ]  #{message}"

	end

	def debug message

		puts "[ DEBUG ] #{message}" if $debug

	end

end

$debug = true
# v = VisionMixer.new $IP, ['Pres', 'Gst'], ['Wide'], 'MP1'
v = VisionMixer.new $IP, [], ['Wide'], 'MP1'
Inputs.new ['Pres', 'Gst', 'Gst'], v
v.loop!