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# frozen_string_literal: true
module Aubio
class Beats
def initialize(aubio_source, params)
# TODO: cleanup param dups
@sample_rate = params[:sample_rate] || 44_100
@window_size = params[:window_size] || 1024
@hop_size = params[:hop_size] || 512
@source = aubio_source
@tempo = Api.new_aubio_tempo('specdiff', @window_size, @hop_size, @sample_rate)
# create output for source
@sample_buffer = Api.new_fvec(@hop_size)
# create output for beat
@out_fvec = Api.new_fvec(1)
end
def each
return enum_for(:each) unless block_given?
total_frames_counter = 0
read_buffer = FFI::MemoryPointer.new(:int)
total_samples = Api.aubio_source_get_duration(@source).to_f
loop do
# Perform tempo calculation
Api.aubio_source_do(@source, @sample_buffer, read_buffer)
Api.aubio_tempo_do(@tempo, @sample_buffer, @out_fvec)
# Retrieve result
is_beat = Api.fvec_get_sample(@out_fvec, 0)
no_of_bytes_read = read_buffer.read_int
total_frames_counter += no_of_bytes_read
if is_beat > 0.0
tempo_samples = Api.aubio_tempo_get_last(@tempo)
tempo_seconds = Api.aubio_tempo_get_last_s(@tempo)
tempo_milliseconds = Api.aubio_tempo_get_last_ms(@tempo)
tempo_confidence = Api.aubio_tempo_get_confidence(@tempo)
output = {
confidence: tempo_confidence,
s: tempo_seconds,
ms: tempo_milliseconds,
sample_no: tempo_samples,
total_samples: total_samples,
rel_start: tempo_samples / total_samples
}
yield output
end
next unless no_of_bytes_read != @hop_size
# there's no more audio to look at
# Let's output one last tempo to mark the end of the file
total_time = total_frames_counter.to_f / @sample_rate.to_f
output = {
confidence: 1.0,
s: total_time,
ms: total_time / 1000.0,
sample_no: total_samples,
total_samples: total_samples
}
yield output
# clean up
Api.del_aubio_tempo(@tempo)
Api.del_fvec(@sample_buffer)
Api.del_fvec(@out_fvec)
break
end
end
end
end
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