Class: AudioToolbox::AudioConverterRef

Inherits:
FFI::Pointer
  • Object
show all
Defined in:
lib/macos/audio_toolbox/audio_converter.rb

AudioConverter.h collapse

PrimeMethod = 
'prmm'

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#from ⇒ Object

Returns the value of attribute from.



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# File 'lib/macos/audio_toolbox/audio_converter.rb', line 3

def from
  @from
end

#to ⇒ Object

Returns the value of attribute to.



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# File 'lib/macos/audio_toolbox/audio_converter.rb', line 4

def to
  @to
end

Instance Method Details

#convert(buffer) ⇒ AudioBufferList

Returns the converted data.

Parameters:

  • buffer (AudioBufferList) —

    the list of buffers to be converted

Returns:

  • (AudioBufferList) —

    the converted data



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# File 'lib/macos/audio_toolbox/audio_converter.rb', line 12

def convert(buffer)
    num_from_packets = (buffer.bytesize / from[:mBytesPerPacket]).floor
    remaining_packets = num_from_packets

    block = Proc.new do |_, num_packets, buffer_list, _|
  unless remaining_packets.zero?
      buffer_list = CoreAudio::AudioBufferList.new(buffer_list)
      buffer_list.buffers.first[:mData] = buffer.buffers.first[:mData]
      buffer_list.buffers.first[:mDataByteSize] = buffer.buffers.first[:mDataByteSize]
  end

  # Report the number of packets actually sent
  num_packets.put_uint32(0, remaining_packets)

  remaining_packets = 0   # No more packets remaining

  0   # All is well
    end

    bytes_per_packet = to[:mBytesPerPacket]
    num_output_packets = (num_from_packets * to.sample_rate / from.sample_rate).floor

    output_list = CoreAudio::AudioBufferList.buffer_list(size:bytes_per_packet * num_output_packets)
    raise("No buffer list") unless output_list

    num_packets = FFI::MemoryPointer.new(:uint32).put_uint32(0, num_output_packets)
    status = AudioToolbox.AudioConverterFillComplexBuffer(self, block, nil, num_packets, output_list, nil)
    raise("Convert failed: '#{[status].pack('L').reverse}'") unless status.zero?

    output_list
end

#prime_method=(method = :normal) ⇒ Object

Parameters:

  • method (Symbol) (defaults to: :normal) —

    :pre, :normal, or :none



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# File 'lib/macos/audio_toolbox/audio_converter.rb', line 45

def prime_method=(method=:normal)
    method = case method
  when :pre  then 0
  when :normal then 1
  when :none then 2
    end
    data = FFI::MemoryPointer.new(:uint32).put_uint32(0, method)
    AudioToolbox.AudioConverterSetProperty(self, PrimeMethod.reverse.unpack('L').first, 4, data)
end