78 lines
2.3 KiB
C++
78 lines
2.3 KiB
C++
/*
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* Chromaprint -- Audio fingerprinting toolkit
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* Copyright (C) 2010 Lukas Lalinsky <lalinsky@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
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* USA
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*/
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#include <limits>
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#include "utils.h"
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#include "fft_lib.h"
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#include "fft.h"
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#include "debug.h"
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using namespace std;
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using namespace Chromaprint;
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FFT::FFT(int frame_size, int overlap, FFTFrameConsumer *consumer)
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: m_window(new double[frame_size]),
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m_buffer_offset(0),
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m_buffer(new short[frame_size]),
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m_frame(frame_size),
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m_frame_size(frame_size),
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m_increment(frame_size - overlap),
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m_consumer(consumer)
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{
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PrepareHammingWindow(m_window, m_window + frame_size);
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for (int i = 0; i < frame_size; i++) {
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m_window[i] /= numeric_limits<short>::max();
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}
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m_lib = new FFTLib(frame_size, m_window);
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}
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FFT::~FFT()
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{
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delete m_lib;
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delete[] m_buffer;
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delete[] m_window;
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}
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void FFT::Reset()
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{
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m_buffer_offset = 0;
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}
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void FFT::Consume(short *input, int length)
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{
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// Special case, just pre-filling the buffer
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if (m_buffer_offset + length < m_frame_size) {
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copy(input, input + length, m_buffer + m_buffer_offset);
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m_buffer_offset += length;
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return;
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}
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// Apply FFT on the available data
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CombinedBuffer<short> combined_buffer(m_buffer, m_buffer_offset, input, length);
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while (combined_buffer.Size() >= m_frame_size) {
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m_lib->ComputeFrame(combined_buffer.Begin(), m_frame.data());
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m_consumer->Consume(m_frame);
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combined_buffer.Shift(m_increment);
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}
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// Copy the remaining input data to the internal buffer
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copy(combined_buffer.Begin(), combined_buffer.End(), m_buffer);
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m_buffer_offset = combined_buffer.Size();
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}
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