Class: Aubio::Onsets

Inherits:
Object
  • Object
show all
Defined in:
lib/aubio/onsets.rb

Instance Method Summary collapse

Constructor Details

#initialize(aubio_source, params) ⇒ Onsets

Returns a new instance of Onsets.



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# File 'lib/aubio/onsets.rb', line 5

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
  @onset = Api.new_aubio_onset('default', @window_size, @hop_size, @sample_rate)
  Api.aubio_onset_set_minioi_ms(@onset, 12.0)
  Api.aubio_onset_set_threshold(@onset, 0.3)

  # create output for source
  @sample_buffer = Api.new_fvec(@hop_size)
  # create output for pitch and beat
  @out_fvec = Api.new_fvec(1)
end

Instance Method Details

#each ⇒ Object 



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# File 'lib/aubio/onsets.rb', line 22

def each
  return enum_for(:each) unless block_given?

  total_frames_counter = 0
  read_buffer = FFI::MemoryPointer.new(:int)

  loop do
    # Perform onset calculation
    Api.aubio_source_do(@source, @sample_buffer, read_buffer)
    Api.aubio_onset_do(@onset, @sample_buffer, @out_fvec)

    # Retrieve result
    onset_new_peak = Api.fvec_get_sample(@out_fvec, 0)
    no_of_bytes_read = read_buffer.read_int
    total_frames_counter += no_of_bytes_read

    if onset_new_peak > 0.0
      onset_seconds = Api.aubio_onset_get_last_s(@onset)
      onset_milliseconds = Api.aubio_onset_get_last_ms(@onset)
      output = {
        s: onset_seconds,
        ms: onset_milliseconds,
        start: (onset_seconds == 0.0 ? 1 : 0),
        end: 0
      }
      yield output
    end

    next unless no_of_bytes_read != @hop_size

    # there's no more audio to look at

    # Let's output one last onset to mark the end of the file
    total_time = total_frames_counter.to_f / @sample_rate.to_f
    output = {
      s: total_time,
      ms: total_time / 1000.0,
      start: 0,
      end: 1
    }
    yield output

    # clean up
    Api.del_aubio_onset(@onset)
    Api.del_fvec(@sample_buffer)
    Api.del_fvec(@out_fvec)

    break
  end
end