Hammerspoon script to control a Display via DDC (brighness, volume) and a Yamaha AV (network) using standard Mac keyboard with MacOS OSD

ddcavcontrol.init.lua

-- ddcavcontrol

-- v1.2.1

-- This Hammerspoon script is intended to do the following:
-- 1) Control External Display Brightness via DDC (utilizing a proper brightness+contrast curve)
-- 2) Control External Display Volume via DDC
-- 3) Control Digital AV Volume via Network (currently works with Yamaha AVs)
-- 4) Use the standard brightness and volume keys of an Apple keyboards
-- 5) Display the standard MacOS OSD as expected

-- Use the Volume Up/Down and Mute keys to control the volume!
-- Use the Brightness Up/Down to control brightness!
-- You can use Shift+Option+Volume Up/Down for fine control!
-- Using the Volume and Mute keys turns on the AV and sets correct input as well.
-- Press SHIFT+Mute to put the AV to StandBy

-- This script requires the waydabber's showosd to display the MacOS OSD!

-- Installation:
-- 1. Get Hammerspoon from https://github.com/Hammerspoon/hammerspoon
-- 2. Get showosd from https://github.com/waydabber/showosd and put it into /usr/local/bin
-- 3. Get m1ddc from https://github.com/waydabber/mm1ddc and put it into /usr/local/bin
-- 4. Select 'Open Config' in Hammerspoon's menu and copy the contents of this script into init.lua
-- 5. Modify the Settings below to fit your configuration
-- 6. Select 'Reload Config' in Hammerspoon's menu

-- External tool locations

SHOWOSD_LOCATION="/usr/local/bin/showosd" -- Get from https://github.com/waydabber/showosd
M1DDC_LOCATION="/usr/local/bin/m1ddc" -- Get from https://github.com/waydabber/m1ddc

-- OS Settings

AV_OS_AUDIO_DEVICE_NAME = "USB Audio Device" -- OS X audio device name to control via network. Leave empty to disable!
DDC_OS_AUDIO_DEVICE_NAME = "LG Ultra HD" -- OS X audio device name to control via DDC

-- Yamaha AV Settings

AV_ADDRESS = "192.168.1.31" -- IP address of the Yamaha AV
AV_INPUT_NAME = "audio1" -- Desired autio input
AV_POWER_INPUT_MANAGEMENT = true -- Set to false to turn off AV power and input control
AV_MAX_VOLUME = 60 -- Limit Max AV volume (AV should be in to Scale mode, not dB mode)

-- DDC Display settings

DISPLAY_MAX_DDC_BRIGHTNESS = 100 -- DDC limit (check with 'm1ddc max brightness') - usually 100
DISPLAY_MAX_DDC_CONTRAST = 100 -- DDC limit (check with 'm1ddc max contrast') - usually 100
DISPLAY_MAX_DDC_VOLUME = 100 -- DDC limit (check with 'm1ddc max volume') - usually 100
DISPLAY_OPTIMAL_CONTRAST = 70 -- Calibrated limit via the Display's own OSD that still does not distort image - usually 70-80
DISPLAY_MINIMAL_CONTRAST = 40 -- Calibrated limit via the Display's own OSD that still makes sense - usually 20-30

-- OSD Constants (don't change)

VOLUME_SEGMENTS = 16
VOLUME_INCREMENT_MINOR = 1
VOLUME_INCREMENT = VOLUME_INCREMENT_MINOR*4
VOLUME_MAX = VOLUME_SEGMENTS * VOLUME_INCREMENT

BRIGHTNESS_SEGMENTS = 16
BRIGHTNESS_INCREMENT_MINOR = 1
BRIGHTNESS_INCREMENT = BRIGHTNESS_INCREMENT_MINOR * 4
BRIGHTNESS_MAX = BRIGHTNESS_SEGMENTS * BRIGHTNESS_INCREMENT

-- Implementation

isMuted = false

currentAVVolume = VOLUME_INCREMENT * 4
currentDDCVolume = VOLUME_INCREMENT * 4
currentBrightness = BRIGHTNESS_INCREMENT * 12

prevDdcBrightness=0
prevDdcContrast=0
prevDdcOSTime=0

-- Set Yamaha AV audio via HTTP

function setAVVolume(showOSD)
	if currentAVVolume<0 then currentAVVolume=0 end
	if currentAVVolume>VOLUME_MAX then currentAVVolume=VOLUME_MAX end
	if showOSD then
		if currentAVVolume == 0 then 
			hs.execute(SHOWOSD_LOCATION .. " mute 0")
		else
			hs.execute(SHOWOSD_LOCATION .. " volume " .. math.floor(currentAVVolume) .. " " .. VOLUME_MAX)
		end
	end
	if (AV_POWER_INPUT_MANAGEMENT) then
		hs.http.doRequest("http://" .. AV_ADDRESS .. "/YamahaExtendedControl/v1/main/setPower?power=on","GET")
		hs.http.doRequest("http://" .. AV_ADDRESS .. "/YamahaExtendedControl/v1/main/setInput?input=" .. AV_INPUT_NAME,"GET")
	end
	local avVolume=math.floor((currentAVVolume/VOLUME_MAX)*AV_MAX_VOLUME*2)
	hs.http.doRequest("http://" .. AV_ADDRESS .. "/YamahaExtendedControl/v1/main/setVolume?volume=" .. avVolume,"GET")
end

-- Set display audio via DDC

function setDDCVolume(showOSD)
	if currentDDCVolume<0 then currentDDCVolume=0 end
	if currentDDCVolume>VOLUME_MAX then currentDDCVolume=VOLUME_MAX end
	if showOSD then
		if currentDDCVolume == 0 then 
			hs.execute(SHOWOSD_LOCATION .. " mute 0")
		else
			hs.execute(SHOWOSD_LOCATION .. " volume " .. math.floor(currentDDCVolume) .. " " .. VOLUME_MAX)
		end
	end
	local ddcVolume=math.floor((currentDDCVolume/VOLUME_MAX)*DISPLAY_MAX_DDC_VOLUME)
	hs.execute(M1DDC_LOCATION .. " set volume " .. ddcVolume)
end

-- Set display brightness via DDC

function setBrightness(showOSD)
	if currentBrightness<0 then currentBrightness=0 end
	if currentBrightness>BRIGHTNESS_MAX then currentBrightness=BRIGHTNESS_MAX end
	if showOSD then
		hs.execute(SHOWOSD_LOCATION .. " brightness " .. math.floor(currentBrightness) .. " " .. BRIGHTNESS_MAX)
	end

	-- You can modify the brighness and contrast curves to fit your display better here:
	
	BRIGHTNESS_TO_CONTRAST_TRESHOLD = BRIGHTNESS_INCREMENT * 4 -- The point after which contrast is decreased instead of brightness
	
	local calculatedBrightness = (math.max(currentBrightness-BRIGHTNESS_TO_CONTRAST_TRESHOLD,0)/(BRIGHTNESS_MAX-BRIGHTNESS_TO_CONTRAST_TRESHOLD)*100)^1.5/10
	local calculatedContrast = 100+math.min(currentBrightness-BRIGHTNESS_TO_CONTRAST_TRESHOLD,0)/(BRIGHTNESS_TO_CONTRAST_TRESHOLD)*100

	--

	local ddcBrightness = math.floor(calculatedBrightness/100*DISPLAY_MAX_DDC_BRIGHTNESS)
	local ddcContrast = math.floor((calculatedContrast/100*(DISPLAY_OPTIMAL_CONTRAST-DISPLAY_MINIMAL_CONTRAST)+DISPLAY_MINIMAL_CONTRAST))
	
	if prevDdcBrightness ~= ddcBrightness or os.time()-prevDdcOSTime > 1 then hs.execute(M1DDC_LOCATION .. " set luminance " .. ddcBrightness) end
	if prevDdcContrast ~= ddcContrast or os.time()-prevDdcOSTime > 1 then hs.execute(M1DDC_LOCATION .. " set contrast " .. ddcContrast) end
	
	prevDdcBrightness = ddcBrightness
	prevDdcContrast = ddcContrast
	prevDdcOSTime = os.time()
		
end

-- Event trap for the  Apple Keyboard's brightness and volume keys

systemeventtap = hs.eventtap.new({hs.eventtap.event.types.systemDefined}, function(mainEvent)
	local event = mainEvent:systemKey()
	local flags = hs.eventtap.checkKeyboardModifiers()
	if event['down'] == false or event['repeat'] == true then
		if hs.audiodevice.defaultOutputDevice():name() == AV_OS_AUDIO_DEVICE_NAME then
			if (event['key'] == "MUTE") then
				if (flags['shift'] or flags['alt'] or flags['cmd'] or flags['ctrl']) and AV_POWER_INPUT_MANAGEMENT then
					hs.execute(SHOWOSD_LOCATION .. " mutedisable")
					hs.http.doRequest("http://" .. AV_ADDRESS .. "/YamahaExtendedControl/v1/main/setPower?power=standby","GET")
				elseif isMuted == false then
					isMuted = true
					hs.execute(SHOWOSD_LOCATION .. " mute 0")
					setAVVolume(false)
					hs.http.doRequest("http://" .. AV_ADDRESS .. "/YamahaExtendedControl/v1/main/setMute?enable=true","GET")
				else
					isMuted = false
					setAVVolume(true)
				end
				return true
			end
			if event['key'] == "SOUND_UP" then
				if flags['shift'] and flags['alt'] then currentAVVolume = currentAVVolume+VOLUME_INCREMENT_MINOR
				else currentAVVolume = math.floor((currentAVVolume)/VOLUME_INCREMENT)*VOLUME_INCREMENT+VOLUME_INCREMENT
				end
				setAVVolume(true)
				return true
			end
			if event['key'] == "SOUND_DOWN" then 
				if flags['shift'] and flags['alt'] then currentAVVolume = currentAVVolume-VOLUME_INCREMENT_MINOR
				else currentAVVolume = math.floor((currentAVVolume-VOLUME_INCREMENT_MINOR)/VOLUME_INCREMENT)*VOLUME_INCREMENT
				end
				setAVVolume(true)
				return true
			end
		end
		
		if hs.audiodevice.defaultOutputDevice():name() == DDC_OS_AUDIO_DEVICE_NAME then
			if (event['key'] == "MUTE") then
				if isMuted == false then
					isMuted = true
					hs.execute(SHOWOSD_LOCATION .. " mute 0")
					hs.execute(M1DDC_LOCATION .. " set mute on")
				else
					isMuted = false
					hs.execute(M1DDC_LOCATION .. " set mute off")
					setDDCVolume(true)
				end
				return true
			end
			if event['key'] == "SOUND_UP" then
				if flags['shift'] and flags['alt'] then currentDDCVolume = currentDDCVolume+VOLUME_INCREMENT_MINOR
				else currentDDCVolume = math.floor((currentDDCVolume)/VOLUME_INCREMENT)*VOLUME_INCREMENT+VOLUME_INCREMENT
				end
				setDDCVolume(true)
				return true
			end
			if event['key'] == "SOUND_DOWN" then 
				if flags['shift'] and flags['alt'] then currentDDCVolume = currentDDCVolume-VOLUME_INCREMENT_MINOR
				else currentDDCVolume = math.floor((currentDDCVolume-VOLUME_INCREMENT_MINOR)/VOLUME_INCREMENT)*VOLUME_INCREMENT
				end
				setDDCVolume(true)
				return true
			end
		end
		
		if event['key'] == "BRIGHTNESS_UP" then
			if flags['shift'] and flags['alt'] then currentBrightness = currentBrightness+BRIGHTNESS_INCREMENT_MINOR
			else currentBrightness = math.floor((currentBrightness)/BRIGHTNESS_INCREMENT)*BRIGHTNESS_INCREMENT+BRIGHTNESS_INCREMENT
			end
			setBrightness(true)
			return true
		end
		if event['key'] == "BRIGHTNESS_DOWN" then 
			if flags['shift'] and flags['alt'] then currentBrightness = currentBrightness-BRIGHTNESS_INCREMENT_MINOR
			else currentBrightness = math.floor((currentBrightness-BRIGHTNESS_INCREMENT_MINOR)/BRIGHTNESS_INCREMENT)*BRIGHTNESS_INCREMENT
			end
			setBrightness(true)
			return true
		end
	end
end)

systemeventtap:start()

-- Event trap for the Bluetooth Apple Keyboard's brightness keys

keyeventtap = hs.eventtap.new({hs.eventtap.event.types.keyDown}, function(mainEvent)
	local keycode = mainEvent:getKeyCode()
	local flags = hs.eventtap.checkKeyboardModifiers()
	if (true) then
		if keycode == 144 then
			if flags['shift'] and flags['alt'] then currentBrightness = currentBrightness+BRIGHTNESS_INCREMENT_MINOR
			else currentBrightness = math.floor((currentBrightness)/BRIGHTNESS_INCREMENT)*BRIGHTNESS_INCREMENT+BRIGHTNESS_INCREMENT
			end
			setBrightness(true)
			return true
		end
		if keycode == 145 then 
			if flags['shift'] and flags['alt'] then currentBrightness = currentBrightness-BRIGHTNESS_INCREMENT_MINOR
			else currentBrightness = math.floor((currentBrightness-BRIGHTNESS_INCREMENT_MINOR)/BRIGHTNESS_INCREMENT)*BRIGHTNESS_INCREMENT
			end
			setBrightness(true)
			return true
		end
	end
end)
	
keyeventtap:start()