Method: AudioToolbox::AudioConverterRef#convert

Defined in:
lib/macos/audio_toolbox/audio_converter.rb

#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