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audioClip.lua
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audioClip.lua
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-- Provides UI so that user can change the start and stop time of a looping
-- soundclip. The UI provides a display of the amplitude of the sound clip
-- versus time.
local AudioClip = {
-- Set via enable()
is_enabled = false,
-- Which softcut voice channels to use when sampling the audio data . Set via enable()
softcut_voices = {},
-- Length of voices in softcut. Set via enable()
voice_duration = nil,
-- How much space to reserve above the audio clip display. Set via enable()
graph_y_pos = nil,
-- Begin time of the loop. Set via enable() and modified via encoders
loop_begin,
-- End time of the loop. Set via enable() and modified via encoders
loop_end,
-- When audio clip is exited this callback is called to provide user adjust loop begin and end times
final_loop_times_callback = nil,
-- voice1 data = {start, duration, sec_per_sample, samples, normalized_samples, largest_sample}
data_v1 = nil,
-- voice2 data = {start, duration, sec_per_sample, samples, normalized_samples, largest_sample}
data_v2 = nil,
-- Following are values that can be changed by a script, though the default values will generally be finet
-- Minimum length in seconds of the audio loop
MIN_LOOP_DURATION,
-- defines where in pixels the audio display starts
LEFT_PX,
-- defines width in pixels of the audioi display
WIDTH_PX,
-- screen level for smallest amplitude
LEVEL_MIN,
-- screen level for largest amplitude
LEVEL_MAX,
-- Update rate for showing current position. In seconds
SHOW_POS_UPDATE_RATE,
-- Brightness level of the vertical lines indicating begin and end of audio loop
BEGIN_END_LINES_LEVEL,
-- For drawing position indicator
POSITION_LINE_LEVEL,
-- For drawing wider position indicator
POSITION_LINE_LEVEL2
}
-- At startup of script, using the pre-init hook, the values in AudioClip will be set to
-- these defaults. This way if a script changes the values, which is completely legit,
-- when the next script is run the values in AudioClip will be reset to these values.
local default_values = {
-- Minimum length in seconds of the audio loop
MIN_LOOP_DURATION = 0.05,
-- defines where in pixels the audio display starts
LEFT_PX = 14,
-- defines width in pixels of the audioi display
WIDTH_PX = 100,
-- screen level for smallest amplitude
LEVEL_MIN = 5,
-- screen level for largest amplitude
LEVEL_MAX = 11,
-- Update rate for showing current position. In seconds. 0.05 makes it move quite smoothly, though may be resource intense
SHOW_POS_UPDATE_RATE = 0.05,
-- Brightness level of the vertical lines indicating begin and end of audio loop
BEGIN_END_LINES_LEVEL = 2,
-- For drawing position indicator
POSITION_LINE_LEVEL = 3,
-- For drawing wider position indicator. A zero level means it won't be drawn at all
POSITION_LINE_LEVEL2 = 0
}
-- Keeping track of when drawing audio position so that can erase it before
-- drawing it at its new location.
local last_x_for_audio_position = nil
-------------------------------------------------------------------------------
--- Actually draws on the screen one of the channels of the audio clip.
-- @tparam table channel_data the audio data obtrained via softcut
-- @tparam boolean up true if should draw channel up from the center line
local function draw_audio_channel(channel_data, up)
local duration_per_pixel = (AudioClip.loop_end - AudioClip.loop_begin) / AudioClip.WIDTH_PX
local y_height_per_channel = math.floor((screen.HEIGHT - AudioClip.graph_y_pos) / 2)
local up_or_down = up and -1 or 1
screen.line_width(1)
screen.aa(0)
log.debug("In draw_audio_channel() and duration_per_pixel="..duration_per_pixel..
" up_or_down="..up_or_down.." y_height_per_channel="..y_height_per_channel)
-- For each vertical line (which corresponds to a time range). But start all the way
-- left and go all the way right in order to show the audio graph for where it is
-- beyond the loop and therefore not active. For these inactive parts the line_x_cnt
-- will be less than 1 or greater than AudioClip.WIDTH_PX.
for line_x_cnt = 1-AudioClip.LEFT_PX, screen.WIDTH-AudioClip.LEFT_PX do
-- Determine begin and end time of what is to be drawn for the x pixel value.
-- Note: this can be beyond the limits of the active part of the loop.
local ampl_line_end_time = AudioClip.loop_begin + line_x_cnt*duration_per_pixel
local ampl_line_begin_time = ampl_line_end_time - duration_per_pixel
-- Determine which samples should be included in the timeslot for the pixel.
-- Note: these indixes can be before or after the active part of the voice
-- data, in which case there is no audio amplitude line to draw.
-- Note: the 0.001 is added just incase time/secs_per_samp provides a value
-- just below an integer due to floating point math issues. But I checked and
-- was not able to find case where this actually made a difference.
local sample_index_begin = math.floor(0.001 + ampl_line_begin_time / channel_data.sec_per_sample) + 1
local sample_index_end = math.floor(0.001 + ampl_line_end_time / channel_data.sec_per_sample)
-- If sample indexes are beyond the range of the data then cannot draw amplitude line
if sample_index_end < 1 then
goto continue
end
if sample_index_begin > #channel_data.normalized_samples then
break
end
local max_amplitude = 0 -- will be between 0 and 1.0
local number_of_samples = 0
for sample_index = sample_index_begin, sample_index_end do
local amplitude = channel_data.normalized_samples[sample_index]
if amplitude ~= nil then
if amplitude > max_amplitude then max_amplitude = amplitude end
number_of_samples = number_of_samples + 1
else
--log.debug("No data for sample_index="..sample_index .. " so skipping")
end
end
-- Determine location of the amplitude line
local x = AudioClip.LEFT_PX + line_x_cnt
local y = screen.HEIGHT - y_height_per_channel
-- Determine color/level for the amplitude line. The idea is to use the ability to
-- have different levels to highlight the larger amplitudes.
local level_for_amplitude = math.floor(AudioClip.LEVEL_MIN +
max_amplitude * (AudioClip.LEVEL_MAX - AudioClip.LEVEL_MIN) + 0.5)
-- But if beyond active part of loop then draw the amplitude quite dimmly. Just want
-- to show user that there is data beyond the extent of the active loop.
if line_x_cnt < 1 or line_x_cnt > AudioClip.WIDTH_PX then
level_for_amplitude = 2
end
local length_of_line = max_amplitude * y_height_per_channel
local length_of_line_in_pixels = math.floor(length_of_line)
local remainder = length_of_line - length_of_line_in_pixels
local end_of_line_y = y + up_or_down*length_of_line_in_pixels
-- Draw max amplitude line if it is at least 1 pixel long
if length_of_line_in_pixels >= 1 then
-- Actually draw the amplitude line
screen.level(level_for_amplitude)
screen.move(x, y)
screen.line(x, end_of_line_y)
screen.stroke()
end
-- Draw single pixel at end of line, using level to indicate how much beyond the
-- line it should go. The pixel should be at a level proportional to the fractional
-- value of the average amplitude.
local pixel_level = level_for_amplitude * remainder
local pixel_x
local pixel_y
if pixel_level > 1.0 then
screen.level(pixel_level)
-- Note: for pixel() pixel_x, pixel_y are the actual pixel coordinate
pixel_x = x - 1
pixel_y = end_of_line_y
if up then pixel_y = pixel_y -1 end
screen.pixel(pixel_x, pixel_y)
screen.fill()
end
-- If at beginning or end of the active audio area then draw vertical line as a y axis.
-- The line starts just above the audio amplitude line, with a 1 pixel gap to indicate
-- the difference.
if line_x_cnt == 1 or line_x_cnt == AudioClip.WIDTH_PX then
screen.level(AudioClip.BEGIN_END_LINES_LEVEL)
screen.move(x, end_of_line_y + 2*up_or_down)
screen.line(x, y + up_or_down*y_height_per_channel)
screen.stroke()
end
-- For debugging
--log.print("=== line_x_cnt="..line_x_cnt.." max_amplitude="..string.format("%.4f", max_amplitude).." length_of_line="..string.format("%.2f", length_of_line) .." length_of_line_in_pixels="..length_of_line_in_pixels.." number_of_samples="..number_of_samples.." level_for_amplitude="..level_for_amplitude)
--log.print("--- x="..x.." y="..y.." end_of_line_y="..end_of_line_y.." pixel_level="..string.format("%.2f", pixel_level).." pixel_x="..tostring(pixel_x).." pixel_y="..tostring(pixel_y))
-- Using an ugly goto because Lua doesn't have a continue statement
::continue::
end
end
--- Does the actual drawing of the audio clip. Separate from AudioClip.redraw() in
-- case script wants to create other buttons in the interface. Does not do
-- screen.clear() nor screen.update(). Those need to be done by the custom redraw()
-- function that draws the other UI elements on the screen.
function AudioClip.draw_audio_graph()
log.debug("In draw_audio_graph()")
-- data = {start, duration, sec_per_sample, samples}
local d1 = AudioClip.data_v1
if d1 ~= nil and log.debug_enabled() then
log.debug("d1.start="..d1.start.." d1.duration="..string.format("%.2f", d1.duration)..
" #d1.samples="..#d1.samples.." d1.largest_sample="..string.format("%.2f", d1.largest_sample))
end
local d2 = AudioClip.data_v2
if d2 ~= nil and log.debug_enabled() then
log.debug("d2.start="..d2.start.." d2.duration="..string.format("%.2f", d2.duration)..
" #d2.samples="..#d2.samples.." d2.largest_sample="..string.format("%.2f", d2.largest_sample))
end
-- Draw each channel, if have data for them
if d1 ~= nil then draw_audio_channel(d1, true) end
if d2 ~= nil then draw_audio_channel(d2, false) end
-- Initiate position polling if haven't done so yet. Reason need to do this after
-- have drawn all the data is because the position callback both draws the new
-- position using ADD mode and erases the old one using DIFFERENCE mode, so the
-- audio graphs need to be fully drawn first. And doing all the drawing takes
-- a while from when first enabled. Need to make sure position drawing is
-- done afterwards.
local voices_drawn = (d1 ~= nil and 1 or 0) + (d2 ~= nil and 1 or 0)
if voices_drawn == #AudioClip.softcut_voices then
-- Initiate position polling now that all audio channels drawn
log.debug("Drew data for both voices so making sure audio position polling running")
AudioClip.initiate_audio_position_polling()
end
-- Display details of graph, but only once all voices have been drawn. This way only do it once.
if voices_drawn == #AudioClip.softcut_voices then
log.debug("Drew data for both voices so displaying all remaining details just once")
-- Display the duration at top of audio display, just below the custom display area
screen.move(screen.WIDTH/2, AudioClip.graph_y_pos + 6)
screen.level(8)
screen.font_face(1)
screen.font_size(8)
screen.aa(0)
screen.text_center(string.format("<- %.2fs ->", AudioClip.loop_end - AudioClip.loop_begin))
-- Display loop begin time in lower left corner
screen.text_rotate(AudioClip.LEFT_PX-2, screen.HEIGHT, string.format("%.2fs", AudioClip.loop_begin), -90)
-- Display loop end time in lower right corner
screen.text_rotate(AudioClip.LEFT_PX + AudioClip.WIDTH_PX + 7, screen.HEIGHT,
string.format("%.2fs", AudioClip.loop_end), -90)
-- Add help info to bottom
screen.move(screen.WIDTH/2, screen.HEIGHT-2)
screen.level(screen.levels.HELP)
screen.font_face(1)
screen.font_size(8)
screen.aa(0)
screen.text_center("Press Key2 to exit")
end
end
-- Returns duration of the wav file in seconds
function AudioClip.wav_file_duration(filename)
-- Determine and return audio length
local ch, samples, samplerate = audio.file_info(filename)
local duration = samples/samplerate
log.debug("In wav_file_duration() and duration="..duration.." for filename="..filename)
return duration
end
-- For drawing a single position indicator line
local function draw_position_indicator_line(x)
screen.move(x, screen.HEIGHT)
screen.line(x, AudioClip.graph_y_pos)
screen.stroke()
end
-- Draws the entire position indicator line
local function draw_position_indicator(x)
-- Setup for drawing
screen.line_width(1)
screen.aa(0)
-- Draw the main indicator line
screen.level(AudioClip.POSITION_LINE_LEVEL)
draw_position_indicator_line(x)
-- If adjacent lines are configured to be drawn to make indicator thicker, then draw those as well
if AudioClip.POSITION_LINE_LEVEL2 ~= nil and AudioClip.POSITION_LINE_LEVEL2 > 0 then
screen.level(AudioClip.POSITION_LINE_LEVEL2)
draw_position_indicator_line(x-1)
draw_position_indicator_line(x+1)
end
end
--- Called via softcut.event_phase(callback) at the update rate specified by
-- softcut.phase_quant(rate). Draws a graphical element on the audio clip that
-- indicates where currently playing.
-- @tparam number voice which voice
-- @tparam number position the current position in the voice, in seconds
local function new_audio_position_callback(voice, position)
-- Apparently get at least one callback for each voice in softcut, even if only
-- wanted to track single one. Therefore just return if voice is not the one
-- wanted callbacks for. This is important to make sure that the position
-- indicator is drawn properly.
if voice ~= AudioClip.softcut_voices[1] then return end
--log.print("New audio position callback. voice="..voice.." position="..string.format("%.3f", position))
-- Determine new x pixel location for the position indicator
local duration_per_pixel = (AudioClip.loop_end - AudioClip.loop_begin) / AudioClip.WIDTH_PX
local x = AudioClip.LEFT_PX+1 + (position - AudioClip.loop_begin)/duration_per_pixel
local x_pixel = math.floor(x + 0.5)
-- If at same pixel then don't need to do anything at all so just return
if x_pixel == last_x_for_audio_position then return end
-- Erase old indicator if it was drawn
if last_x_for_audio_position ~= nil then
-- Use subtract mode so can just draw the position indicator again in order to erase it
screen.blend_mode("difference")
-- Draw the indicator at the old position in order to erase it
draw_position_indicator(last_x_for_audio_position)
end
-- Draw the position indicator at the new position
-- Use add mode so that can erase just by using subtract mode
screen.blend_mode("add")
draw_position_indicator(x_pixel)
-- Remember where drew the indicator so that it can be erased later
last_x_for_audio_position = x_pixel
-- Actually make the changes visible
screen.update()
-- Restore drawning mode to the standard one
screen.blend_mode("default")
end
--- Called via softcut.event_render(callback) when softcut.render_buffer() is called
-- and the data has been processed. Used to convert a voice into a smaller sample rate
-- so that the data can be used to visualize the amplitude of the audio clip.
local function buffer_content_processed_callback(ch, start, sec_per_sample, samples)
log.debug("In buffer_content_processed_callback() ch="..ch.." start="..start..
" sec_per_sample="..string.format("%.6f", sec_per_sample).." #samples="..#samples)
-- Want to normalize the samples so that the largest absolute value is 1.0.
-- This way the audio graph will be as tall as possible.
local largest_sample = 0
for _, sample in ipairs(samples) do
if math.abs(sample) > largest_sample then largest_sample = math.abs(sample) end
end
local normalized_samples = {}
for _, sample in ipairs(samples) do
table.insert(normalized_samples, math.abs(sample) / largest_sample)
end
-- Store the data so that it can be drawn
local data = {
start = start,
duration = sec_per_sample * #samples,
sec_per_sample = sec_per_sample,
samples = samples,
normalized_samples = normalized_samples,
largest_sample = largest_sample
}
if ch == 1 then
AudioClip.data_v1 = data
else
AudioClip.data_v2 = data
end
-- Since have processed data should draw the audio graphs
AudioClip.draw_audio_graph()
screen.update()
end
-- For keeping track of whether currently polling position. Used to prevent trying to
-- start polling if already have done so.
local currently_position_polling = false
-- Initiates polling of the position within the audio loop so can draw
-- it on audio graph. If already polling the position then this function
-- won't actually do anything. Therefore can call it multiple times.
-- @tparam number voice_duration length in seconds of the voice
function AudioClip.initiate_audio_position_polling()
-- If already polling then done
if currently_position_polling then return end
currently_position_polling = true
-- Configure so that new_audio_position_callback() is called every update_rate
-- seconds. This allows an indicator to be drawn that shows where in clip we are.
-- Only need to do this for one ofo the voices
softcut.phase_quant(AudioClip.softcut_voices[1], AudioClip.SHOW_POS_UPDATE_RATE)
softcut.event_phase(new_audio_position_callback)
log.debug("Starting polling for position. Will be calling new_audio_position_callback() for voice="..AudioClip.softcut_voices[1])
softcut.poll_start_phase()
end
-- Converts the audio in Softcut buffer into data arrays that can be graphed.
-- Only called once for the audio data. Don't need to call it every time encoder
-- changed. buffer_content_processed_callback() is called when the data has finished
-- being processed.
function AudioClip.initiate_audio_data_processing(voice_duration)
log.debug("Initiating audio data processing. voice_duration="..tostring(voice_duration))
-- register callbacks that handles the resampled audio data.
-- And then initiate the resampling
softcut.event_render(buffer_content_processed_callback)
for _, voice in ipairs(AudioClip.softcut_voices) do
local start = 0
local max_samples = 200 * voice_duration -- 200 samples per second
softcut.render_buffer(voice, start, voice_duration, max_samples)
end
end
-- Updates begin and end time of the audio loop
local function set_audio_loop_params()
for _, voice in ipairs(AudioClip.softcut_voices) do
log.debug("Setting audio params for voice="..voice..
" loop_begin="..string.format("%.2f", AudioClip.loop_begin)..
" loop_end="..string.format("%.2f", AudioClip.loop_end))
-- Start loop at AudioClip.loop_begin
softcut.loop_start(voice, AudioClip.loop_begin)
-- Play till AudioClip.loop_end
softcut.loop_end(voice, AudioClip.loop_end)
-- Enable looping in case it has not yet been enabled
softcut.loop(voice, 1)
end
end
-- Resets values for Audio Clip. Should be called when Audio Clip exited
-- and at startup
function AudioClip.reset()
-- Stop polling of audio phase since it takes resources
softcut.poll_stop_phase()
currently_position_polling = false
-- Don't need to worry about displaying audio position anymore
last_x_for_audio_position = nil
-- Mark as disabled
AudioClip.disable()
-- Clear the other params
AudioClip.data_v1 = nil
AudioClip.data_v2 = nil
AudioClip.voice_duration = nil
AudioClip.graph_y_pos = nil
end
--- Called when key2 is hit by user to exit the audio clip screen
function AudioClip.exit()
log.print("Exiting audio clip screen")
-- Reset params for Audio Clip
AudioClip.reset()
-- Call callback to alert main script that begin and end times might have been changed
if AudioClip.final_loop_times_callback ~= nil then
AudioClip.final_loop_times_callback(AudioClip.loop_begin, AudioClip.loop_end)
end
-- Call the app's redraw since exiting the audio graph screen
redraw()
end
function AudioClip.disable()
log.debug("In AudioClip.disable()")
AudioClip.is_enabled = false
end
--- Used to setup audio clip screen and switch to it.
-- @tparam number voice1 which voice in softcut to use
-- @tparam number voice2 second voice in softcut to use. Can be set to nil.
-- @tparam number voice_duration length of the voice in seconds
-- @tparam number graph_y_pos y pixel value, below which can be used for displaying audio
-- @tparam number loop_begin Where in voice the loop begin is. If nil then will use beginning of voice
-- @tparam number loop_end Where in voice the loop ends. If nil then will use end of voice
-- @tparam function final_loop_times_callback When audio clip is exited this callback is called to provide user adjust loop begin and end times
function AudioClip.enable(voice1, voice2, voice_duration, graph_y_pos, loop_begin, loop_end, final_loop_times_callback)
log.print("Entering audio clip screen and voice_duration="..tostring(voice_duration))
-- Keep track of params
AudioClip.is_enabled = true
AudioClip.softcut_voices = {voice1, voice2}
AudioClip.graph_y_pos = graph_y_pos
AudioClip.voice_duration = voice_duration
AudioClip.loop_begin = loop_begin or 0
AudioClip.loop_end = loop_end or voice_duration
AudioClip.final_loop_times_callback = final_loop_times_callback
-- Loop the voices using proper begin and end times
set_audio_loop_params()
-- Get the raw data from softcut buffer
AudioClip.initiate_audio_data_processing(voice_duration)
-- Call clear() and update() to clear the screen so that can then display the
-- audio clip screen
screen.clear()
screen.update()
end
--- Returns true if clipAudio screen is currently enabled
function AudioClip.enabled()
return AudioClip.is_enabled ~= nil and AudioClip.is_enabled
end
-- If k3 is down then use fine resolution mode for ehcoders
local k3_down = false
local function encoder_increment()
return k3_down and 0.01 or 0.2
end
-- Handles key presses for the audio clip screen. When k2 is hit the audio
-- clip screen is exited. And when k3 is hit the variable k3_down is updated
-- so that the encoders can have fine resolution.
function AudioClip.key(n, down)
log.debug("AudioClip key pressed n=" .. n .. " delta=" .. down)
-- If key2 hit then exit clip audio mode
if n == 2 then
AudioClip.exit()
end
-- If it is key3 then update variable k3_down
if n == 3 then
k3_down = (down == 1)
end
end
-- Handles encoder turns for the audio clip screen. Adjusts the loop begin and end times.
function AudioClip.enc(n, delta)
log.debug("AudioClip encoder changed n=" .. n .. " delta=" .. delta)
if n == 2 then
-- encoder 2 turned so adjust loop begin time
AudioClip.loop_begin = util.clamp(AudioClip.loop_begin + encoder_increment() * delta,
0, AudioClip.voice_duration - AudioClip.MIN_LOOP_DURATION)
log.debug("AudioClip.loop_begin=" .. string.format("%.2f", AudioClip.loop_begin))
-- Make sure the loop_end is still valid
if AudioClip.loop_end < AudioClip.loop_begin + AudioClip.MIN_LOOP_DURATION then
AudioClip.loop_end = AudioClip.loop_begin + AudioClip.MIN_LOOP_DURATION
log.debug("Also adjusted AudioClip.loop_end=" .. string.format("%.2f", AudioClip.loop_end))
end
set_audio_loop_params()
-- Clear last_x since about to redraw entire audio screen which means don't need
-- to erase old position indicator
last_x_for_audio_position = nil
-- Redraw whole aduio screen by calling the application's redraw()
redraw()
elseif n ==3 then
-- encoder 3 turned so adjust loop end
AudioClip.loop_end = util.clamp(AudioClip.loop_end + encoder_increment() * delta,
AudioClip.MIN_LOOP_DURATION, AudioClip.voice_duration)
log.debug("AudioClip.loop_end=" .. string.format("%.2f", AudioClip.loop_end))
-- Make sure the loop_begin is still valid
if AudioClip.loop_begin > AudioClip.loop_end - AudioClip.MIN_LOOP_DURATION then
AudioClip.loop_begin = AudioClip.loop_end - AudioClip.MIN_LOOP_DURATION
log.debug("Also adjusted AudioClip.loop_begin=" .. string.format("%.2f", AudioClip.loop_begin))
end
set_audio_loop_params()
-- Clear last_x since about to redraw entire audio screen which means don't need
-- to erase old position indicator
last_x_for_audio_position = nil
-- Redraw whole aduio screen by calling the application's redraw()
redraw()
end
end
-- Use pre-init hook to initialize parameters within AudioClip. This way, if a script changes
-- the parameters then they will be reset to their default values before the script uses the
-- values.
local function initialize_audio_clip()
-- Copy all elements from default_values into AudioClip table
for i, v in pairs(default_values) do
AudioClip[i] = v
end
-- Need to disable audio clip in case the last script run had it enabled
reset()
end
local hooks = require 'core/hook'
hooks["script_pre_init"]:register("Pre init hook for audioClip to initialize values",
initialize_audio_clip)
return AudioClip