-- most of this code is stolen from https://github.com/stephenjbradshaw/SPEAR-to-MIDI
local split = string.split
local gsub = string.gsub
function sublist_index_avg(list, index)
local sum = 0
for _, v in list do
sum += v[index]
end
return sum / #list
end
function process_line(line, de)
local partial = {}
local split_line = split(line, " ")
while #split_line > 0 do
local reachedEnd = false
local timepoint = {}
for i = 0, 3 do
local val = table.remove(split_line, 1)
if val == nil then
reachedEnd = true
break
end
local item = gsub(val, ",", ".")
table.insert(timepoint, item)
end
if reachedEnd == true then
break
end
table.insert(partial, timepoint)
end
return partial
end
function scaleValue(value, inMin, inMax, outMin, outMax)
local normalizedValue = (value - inMin) / (inMax - inMin)
local scaledValue = normalizedValue * (outMax - outMin) + outMin
return scaledValue
end
return function(data, debugEverything)
local lines = split(data, "\n")
-- strip metadata
for i = 1, 5 do
table.remove(lines, 1)
end
local partials = {}
for _, v in ipairs(lines) do
table.insert(partials, process_line(v, debugEverything))
end
local min_amp = sublist_index_avg(partials[1], 2)
local max_amp = sublist_index_avg(partials[1], 2)
for _, partial in ipairs(partials) do
local temp_amp = sublist_index_avg(partial, 2)
if temp_amp < min_amp then
min_amp = temp_amp
end
if temp_amp > max_amp then
max_amp = temp_amp
end
end
local data = {}
for _, partial in ipairs(partials) do
local average_freq = sublist_index_avg(partial, 1)
local average_amp = sublist_index_avg(partial, 2)
local volume = scaleValue(average_amp, min_amp, max_amp, 0, 1)
if partial[1] == nil then
continue
end
local on_time = partial[1][1]
local off_time = partial[#partial][1]
table.insert(data, {
startTime = on_time,
endTime = off_time,
freq = average_freq,
vol_mult = volume
})
end
return data
end
