Sync to sound

[NÖÖB]

New, much improved version in post #6

Hi! Here's a demo of syncing pictures to sound; using source:tell("samples"), I'm able to tell if the currently playing audio track is at this and that position, and then show pictures when at that position. This demo is hardcoded to 120 bpm. It's a mess, and it eventually goofs up when the audio loops a number of times.
Let me know if it works on your computer It could need some more error handling, such as if dragging the window around the time the audio is about to loop (64 counts), the routine will not work again. And if anyone know why it sometimes messes up when the audio loops, please share it here -- hopefully someone can use this concept and make it more usable..
[edit] changing this line "if position <= 1024 and position < 1409024 then looped = 0 end" to "if position <= 11008 and position < 1409024 then looped = 0 end" makes the looping more stable.

[Robin]

That's the same as if position < 1409024 then looped = 0 end, unless you meant >= instead of <=.

[NÖÖB]

Wow.. hehe

if position <= 11008 should be enough..

[Robin]

By the way, I see now I was wrong. It's an and, not an or. So the first one means if position <= 1024 then ... and the other if position <= 11008 then ....

[coffee]

This is nice. I think the command idea is good and even useful. However the concept lost himself because the track have always same tone and bpm. Another good demo would be track sudden change mood to a slow thing and you issue a command to do something different.

[NÖÖB]

New version do download the .love, as the code depends on the audio file inside.

Code: Select all

-- Synchronizing graphics to music.
-- --------------------------------------
--	In order for this to work, the music you're using has to be a perfect loop, with constant intervals between beats, and no silence at the beginning or the end of the music.
-- You have to know a  number of things about the music: In this example, there are 352800 samples; 4 beats per bar (or measure), and 4 bars (4/4 time signature) at 120 bpm.
-- So, to sync at every beat: 4 beats * 4 bars = 16 beats. 352800 samples / 16 beats = 22050 samples.
-- With the supplied music, use 22050 samples in the ssyncUpdate function call to sync every quarter note. Divide by 32 and use 11025 samples to sync every eight note.

function love.load()
	ch0 = love.audio.newSource("120.ogg", "stream")			ch0:setLooping(true)
	love.audio.play(ch0)

	image1 = love.graphics.newImage("skel1.png")				image1:setFilter("nearest", "nearest")	
	image2 = love.graphics.newImage("skel2.png")				image2:setFilter("nearest", "nearest")
	imageCur = image1
end

function love.update(dt)
	ssyncUpdate(ch0, 22050)
	if ssyncPos % 2 == 0 then imageCur = image1 else imageCur = image2 end
end

function love.draw()
	love.graphics.print("ssyncSample: " .. ssyncSample, 10, 10)
	love.graphics.print("ssyncPos: " .. ssyncPos, 160, 10)
	love.graphics.draw(imageCur, 336, 236, 0, 4, 4)
end

function ssyncUpdate(ssyncChannel, ssyncSpeed)
	ssyncSample = ssyncChannel:tell("samples")
	ssyncPos = math.floor(ssyncSample / ssyncSpeed)
end

This is nice. I think the command idea is good and even useful. However the concept lost himself because the track have always same tone and bpm. Another good demo would be track sudden change mood to a slow thing and you issue a command to do something different.

If you know that the track changes tempo from, say 120bpm to 150bpm at sample 705600, then in this new version you'd just change ssyncUpdate(ch0, 22050) to ssyncUpdate(ch0, 17640) when you reach that sample. Well, it's a little more complicated than that; you'd have to have a script for that one piece of music, but I guess it's doable.