src/sound/AudioTimeStretcher.cpp

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam and QMUL.

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "AudioTimeStretcher.h"

#include <QtGlobal>

#include <fstream>
#include <cstring>

namespace Rosegarden
{

    // (Unused)
    // static double mod(double x, double y) { return x - (y * floor(x / y)); }
static float modf(float x, float y) { return x - (y * floorf(x / y)); }

    // (Unused)
    // static double princarg(double a) { return mod(a + M_PI, -2 * M_PI) + M_PI; }
static float princargf(float a) { return modf(a + M_PI, -2 * M_PI) + M_PI; }


//#define DEBUG_AUDIO_TIME_STRETCHER 1

AudioTimeStretcher::AudioTimeStretcher(size_t sampleRate,
                                       size_t channels,
                                       float ratio,
                                       bool sharpen,
                                       size_t maxOutputBlockSize) :
    m_sampleRate(sampleRate),
    m_channels(channels),
    m_maxOutputBlockSize(maxOutputBlockSize),
    m_ratio(ratio),
    m_sharpen(sharpen),
    m_totalCount(0),
    m_transientCount(0),
    m_n2sum(0),
    m_n2total(0),
    m_adjustCount(50)
{
    pthread_mutex_t initialisingMutex = PTHREAD_MUTEX_INITIALIZER;
    memcpy(&m_mutex, &initialisingMutex, sizeof(pthread_mutex_t));

    initialise();
}

AudioTimeStretcher::~AudioTimeStretcher()
{
    std::cerr << "AudioTimeStretcher::~AudioTimeStretcher" << std::endl;

    std::cerr << "AudioTimeStretcher::~AudioTimeStretcher: actual ratio = " << (m_totalCount > 0 ? (float (m_n2total) / float(m_totalCount * m_n1)) : 1.f) << ", ideal = " << m_ratio << ", nominal = " << getRatio() << ")" << std::endl;

    cleanup();

    pthread_mutex_destroy(&m_mutex);
}

void
AudioTimeStretcher::initialise()
{
    std::cerr << "AudioTimeStretcher::initialise" << std::endl;

    calculateParameters();

    m_analysisWindow = new SampleWindow<float>(SampleWindow<float>::Hanning, m_wlen);
    m_synthesisWindow = new SampleWindow<float>(SampleWindow<float>::Hanning, m_wlen);

    m_prevPhase = new float *[m_channels];
    m_prevAdjustedPhase = new float *[m_channels];

    m_prevTransientMag = (float *)fftwf_malloc(sizeof(float) * (m_wlen / 2 + 1));
    m_prevTransientScore = 0;
    m_prevTransient = false;

    m_tempbuf = (float *)fftwf_malloc(sizeof(float) * m_wlen);

    m_time = new float *[m_channels];
    m_freq = new fftwf_complex *[m_channels];
    m_plan = new fftwf_plan[m_channels];
    m_iplan = new fftwf_plan[m_channels];

    m_inbuf = new RingBuffer<float> *[m_channels];
    m_outbuf = new RingBuffer<float> *[m_channels];
    m_mashbuf = new float *[m_channels];

    m_modulationbuf = (float *)fftwf_malloc(sizeof(float) * m_wlen);

    for (size_t c = 0; c < m_channels; ++c) {

        m_prevPhase[c] = (float *)fftwf_malloc(sizeof(float) * (m_wlen / 2 + 1));
        m_prevAdjustedPhase[c] = (float *)fftwf_malloc(sizeof(float) * (m_wlen / 2 + 1));

        m_time[c] = (float *)fftwf_malloc(sizeof(float) * m_wlen);
        m_freq[c] = (fftwf_complex *)fftwf_malloc(sizeof(fftwf_complex) *
                                                  (m_wlen / 2 + 1));

        m_plan[c] = fftwf_plan_dft_r2c_1d(m_wlen, m_time[c], m_freq[c], FFTW_ESTIMATE);
        m_iplan[c] = fftwf_plan_dft_c2r_1d(m_wlen, m_freq[c], m_time[c], FFTW_ESTIMATE);

        m_outbuf[c] = new RingBuffer<float>
            ((m_maxOutputBlockSize + m_wlen) * 2);
        m_inbuf[c] = new RingBuffer<float>
            (lrintf(m_outbuf[c]->getSize() / m_ratio) + m_wlen);

        std::cerr << "making inbuf size " << m_inbuf[c]->getSize() << " (outbuf size is " << m_outbuf[c]->getSize() << ", ratio " << m_ratio << ")" << std::endl;


        m_mashbuf[c] = (float *)fftwf_malloc(sizeof(float) * m_wlen);

        for (size_t i = 0; i < m_wlen; ++i) {
            m_mashbuf[c][i] = 0.0;
        }

        for (size_t i = 0; i <= m_wlen/2; ++i) {
            m_prevPhase[c][i] = 0.0;
            m_prevAdjustedPhase[c][i] = 0.0;
        }
    }

    for (size_t i = 0; i < m_wlen; ++i) {
        m_modulationbuf[i] = 0.0;
    }

    for (size_t i = 0; i <= m_wlen/2; ++i) {
        m_prevTransientMag[i] = 0.0;
    }
}

void
AudioTimeStretcher::calculateParameters()
{
    std::cerr << "AudioTimeStretcher::calculateParameters" << std::endl;

    m_wlen = 1024;

    //!!! In transient sharpening mode, we need to pick the window
    //length so as to be more or less fixed in audio duration (i.e. we
    //need to exploit the sample rate)

    //!!! have to work out the relationship between wlen and transient
    //threshold

    if (m_ratio < 1) {
        if (m_ratio < 0.4) {
            m_n1 = 1024;
            m_wlen = 2048;
        } else if (m_ratio < 0.8) {
            m_n1 = 512;
        } else {
            m_n1 = 256;
        }
        if (shouldSharpen()) {
            m_wlen = 2048;
        }
        m_n2 = lrintf(m_n1 * m_ratio);
    } else {
        if (m_ratio > 2) {
            m_n2 = 512;
            m_wlen = 4096;
        } else if (m_ratio > 1.6) {
            m_n2 = 384;
            m_wlen = 2048;
        } else {
            m_n2 = 256;
        }
        if (shouldSharpen()) {
            if (m_wlen < 2048) m_wlen = 2048;
        }
        m_n1 = lrintf(m_n2 / m_ratio);
        if (m_n1 == 0) {
            m_n1 = 1;
            m_n2 = m_ratio;
        }
    }

    m_transientThreshold = lrintf(m_wlen / 4.5);

    m_totalCount = 0;
    m_transientCount = 0;
    m_n2sum = 0;
    m_n2total = 0;
    m_n2list.clear();

    std::cerr << "AudioTimeStretcher: channels = " << m_channels
              << ", ratio = " << m_ratio
              << ", n1 = " << m_n1 << ", n2 = " << m_n2 << ", wlen = "
              << m_wlen << ", max = " << m_maxOutputBlockSize << std::endl;
//              << ", outbuflen = " << m_outbuf[0]->getSize() << std::endl;
}

void
AudioTimeStretcher::cleanup()
{
    std::cerr << "AudioTimeStretcher::cleanup" << std::endl;

    for (size_t c = 0; c < m_channels; ++c) {

        fftwf_destroy_plan(m_plan[c]);
        fftwf_destroy_plan(m_iplan[c]);

        fftwf_free(m_time[c]);
        fftwf_free(m_freq[c]);

        fftwf_free(m_mashbuf[c]);
        fftwf_free(m_prevPhase[c]);
        fftwf_free(m_prevAdjustedPhase[c]);

        delete m_inbuf[c];
        delete m_outbuf[c];
    }

    fftwf_free(m_tempbuf);
    fftwf_free(m_modulationbuf);
    fftwf_free(m_prevTransientMag);

    delete[] m_prevPhase;
    delete[] m_prevAdjustedPhase;
    delete[] m_inbuf;
    delete[] m_outbuf;
    delete[] m_mashbuf;
    delete[] m_time;
    delete[] m_freq;
    delete[] m_plan;
    delete[] m_iplan;

    delete m_analysisWindow;
    delete m_synthesisWindow;
}

void
AudioTimeStretcher::setRatio(float ratio)
{
    pthread_mutex_lock(&m_mutex);

    size_t formerWlen = m_wlen;
    m_ratio = ratio;

    std::cerr << "AudioTimeStretcher::setRatio: new ratio " << ratio
              << std::endl;

    calculateParameters();

    if (m_wlen == formerWlen) {

        // This is the only container whose size depends on m_ratio

        RingBuffer<float> **newin = new RingBuffer<float> *[m_channels];

        size_t formerSize = m_inbuf[0]->getSize();
        size_t newSize = lrintf(m_outbuf[0]->getSize() / m_ratio) + m_wlen;

        std::cerr << "resizing inbuf from " << formerSize << " to "
                  << newSize << " (outbuf size is " << m_outbuf[0]->getSize() << ", ratio " << m_ratio << ")" << std::endl;

        if (formerSize != newSize) {

            size_t ready = m_inbuf[0]->getReadSpace();

            for (size_t c = 0; c < m_channels; ++c) {
                newin[c] = new RingBuffer<float>(newSize);
            }

            if (ready > 0) {

                size_t copy = std::min(ready, newSize);
                float *tmp = new float[ready];

                for (size_t c = 0; c < m_channels; ++c) {
                    m_inbuf[c]->read(tmp, ready);
                    newin[c]->write(tmp + ready - copy, copy);
                }

                delete[] tmp;
            }

            for (size_t c = 0; c < m_channels; ++c) {
                delete m_inbuf[c];
            }

            delete[] m_inbuf;
            m_inbuf = newin;
        }

    } else {

        std::cerr << "wlen changed" << std::endl;
        cleanup();
        initialise();
    }

    pthread_mutex_unlock(&m_mutex);
}

size_t
AudioTimeStretcher::getProcessingLatency() const
{
    return getWindowSize() - getInputIncrement();
}

size_t
AudioTimeStretcher::getRequiredInputSamples() const
{
    size_t rv;
    pthread_mutex_lock(&m_mutex);

    if (m_inbuf[0]->getReadSpace() >= m_wlen) rv = 0;
    else rv = m_wlen - m_inbuf[0]->getReadSpace();

    pthread_mutex_unlock(&m_mutex);
    return rv;
}

void
AudioTimeStretcher::putInput(float **input, size_t samples)
{
    pthread_mutex_lock(&m_mutex);

    // We need to add samples from input to our internal buffer.  When
    // we have m_windowSize samples in the buffer, we can process it,
    // move the samples back by m_n1 and write the output onto our
    // internal output buffer.  If we have (samples * ratio) samples
    // in that, we can write m_n2 of them back to output and return
    // (otherwise we have to write zeroes).

    // When we process, we write m_wlen to our fixed output buffer
    // (m_mashbuf).  We then pull out the first m_n2 samples from that
    // buffer, push them into the output ring buffer, and shift
    // m_mashbuf left by that amount.

    // The processing latency is then m_wlen - m_n2.

    size_t consumed = 0;

    while (consumed < samples) {

	size_t writable = m_inbuf[0]->getWriteSpace();
	writable = std::min(writable, samples - consumed);

	if (writable == 0) {
#ifdef DEBUG_AUDIO_TIME_STRETCHER
	    std::cerr << "WARNING: AudioTimeStretcher::putInput: writable == 0 (inbuf has " << m_inbuf[0]->getReadSpace() << " samples available for reading, space for " << m_inbuf[0]->getWriteSpace() << " more)" << std::endl;
#endif
            if (m_inbuf[0]->getReadSpace() < m_wlen ||
                m_outbuf[0]->getWriteSpace() < m_n2) {
                std::cerr << "WARNING: AudioTimeStretcher::putInput: Inbuf has " << m_inbuf[0]->getReadSpace() << ", outbuf has space for " << m_outbuf[0]->getWriteSpace() << " (n2 = " << m_n2 << ", wlen = " << m_wlen << "), won't be able to process" << std::endl;
                break;
            }
	} else {

#ifdef DEBUG_AUDIO_TIME_STRETCHER
            std::cerr << "writing " << writable << " from index " << consumed << " to inbuf, consumed will be " << consumed + writable << std::endl;
#endif

            for (size_t c = 0; c < m_channels; ++c) {
                m_inbuf[c]->write(input[c] + consumed, writable);
            }
            consumed += writable;
        }

	while (m_inbuf[0]->getReadSpace() >= m_wlen &&
	       m_outbuf[0]->getWriteSpace() >= m_n2) {

	    // We know we have at least m_wlen samples available
	    // in m_inbuf.  We need to peek m_wlen of them for
	    // processing, and then read m_n1 to advance the read
	    // pointer.

            for (size_t c = 0; c < m_channels; ++c) {

#ifndef NDEBUG
                size_t got = m_inbuf[c]->peek(m_tempbuf, m_wlen);
                Q_ASSERT(got == m_wlen);
#endif

                analyseBlock(c, m_tempbuf);
            }

            bool transient = false;
            if (shouldSharpen()) transient = isTransient();

            size_t n2 = m_n2;

            if (transient) {
                n2 = m_n1;
            }

            ++m_totalCount;
            if (transient) ++m_transientCount;

            m_n2sum += n2;
            m_n2total += n2;

            if (m_totalCount > 50 && m_transientCount < m_totalCount) {

                int fixed = m_transientCount * m_n1;

                float idealTotal = m_totalCount * m_n1 * m_ratio;
                float idealSquashy = idealTotal - fixed;

                float squashyCount = m_totalCount - m_transientCount;

                float fn2 = idealSquashy / squashyCount;

                n2 = int(fn2);

                float remainder = fn2 - n2;
                if (drand48() < remainder) ++n2;

#ifdef DEBUG_AUDIO_TIME_STRETCHER
                if (n2 != m_n2) {
                    std::cerr << m_n2 << " -> " << n2 << " (ideal = " << (idealSquashy / squashyCount) << ")" << std::endl;
                }
#endif
            }

            for (size_t c = 0; c < m_channels; ++c) {

                synthesiseBlock(c, m_mashbuf[c],
                                c == 0 ? m_modulationbuf : nullptr,
                                m_prevTransient ? m_n1 : m_n2);


#ifdef DEBUG_AUDIO_TIME_STRETCHER
                std::cerr << "writing first " << m_n2 << " from mashbuf, skipping " << m_n1 << " on inbuf " << std::endl;
#endif
                m_inbuf[c]->skip(m_n1);

                for (size_t i = 0; i < n2; ++i) {
                    if (m_modulationbuf[i] > 0.f) {
                        m_mashbuf[c][i] /= m_modulationbuf[i];
                    }
                }

                m_outbuf[c]->write(m_mashbuf[c], n2);

                for (size_t i = 0; i < m_wlen - n2; ++i) {
                    m_mashbuf[c][i] = m_mashbuf[c][i + n2];
                }

                for (size_t i = m_wlen - n2; i < m_wlen; ++i) {
                    m_mashbuf[c][i] = 0.0f;
                }
            }

            m_prevTransient = transient;

            for (size_t i = 0; i < m_wlen - n2; ++i) {
                m_modulationbuf[i] = m_modulationbuf[i + n2];
	    }

	    for (size_t i = m_wlen - n2; i < m_wlen; ++i) {
                m_modulationbuf[i] = 0.0f;
	    }

            if (!transient) m_n2 = n2;
	}


#ifdef DEBUG_AUDIO_TIME_STRETCHER
	std::cerr << "loop ended: inbuf read space " << m_inbuf[0]->getReadSpace() << ", outbuf write space " << m_outbuf[0]->getWriteSpace() << std::endl;
#endif
    }

#ifdef DEBUG_AUDIO_TIME_STRETCHER
    std::cerr << "AudioTimeStretcher::putInput returning" << std::endl;
#endif

    pthread_mutex_unlock(&m_mutex);

//    std::cerr << "ratio: nominal: " << getRatio() << " actual: "
//              << m_total2 << "/" << m_total1 << " = " << float(m_total2) / float(m_total1) << " ideal: " << m_ratio << std::endl;
}

size_t
AudioTimeStretcher::getAvailableOutputSamples() const
{
    pthread_mutex_lock(&m_mutex);

    size_t rv = m_outbuf[0]->getReadSpace();

    pthread_mutex_unlock(&m_mutex);
    return rv;
}

void
AudioTimeStretcher::getOutput(float **output, size_t samples)
{
    pthread_mutex_lock(&m_mutex);

    if (m_outbuf[0]->getReadSpace() < samples) {
	std::cerr << "WARNING: AudioTimeStretcher::getOutput: not enough data (yet?) (" << m_outbuf[0]->getReadSpace() << " < " << samples << ")" << std::endl;
	size_t fill = samples - m_outbuf[0]->getReadSpace();
        for (size_t c = 0; c < m_channels; ++c) {
            for (size_t i = 0; i < fill; ++i) {
                output[c][i] = 0.0;
            }
            m_outbuf[c]->read(output[c] + fill, m_outbuf[c]->getReadSpace());
        }
    } else {
#ifdef DEBUG_AUDIO_TIME_STRETCHER
	std::cerr << "enough data - writing " << samples << " from outbuf" << std::endl;
#endif
        for (size_t c = 0; c < m_channels; ++c) {
            m_outbuf[c]->read(output[c], samples);
        }
    }

#ifdef DEBUG_AUDIO_TIME_STRETCHER
    std::cerr << "AudioTimeStretcher::getOutput returning" << std::endl;
#endif

    pthread_mutex_unlock(&m_mutex);
}

void
AudioTimeStretcher::analyseBlock(size_t c, float *buf)
{
    size_t i;

    // buf contains m_wlen samples

#ifdef DEBUG_AUDIO_TIME_STRETCHER
    std::cerr << "AudioTimeStretcher::analyseBlock (channel " << c << ")" << std::endl;
#endif

    m_analysisWindow->cut(buf);

    for (i = 0; i < m_wlen/2; ++i) {
	float temp = buf[i];
	buf[i] = buf[i + m_wlen/2];
	buf[i + m_wlen/2] = temp;
    }

    for (i = 0; i < m_wlen; ++i) {
	m_time[c][i] = buf[i];
    }

    fftwf_execute(m_plan[c]); // m_time -> m_freq
}

bool
AudioTimeStretcher::isTransient()
{
    int count = 0;

    for (size_t i = 0; i <= m_wlen/2; ++i) {

        float real = 0.f, imag = 0.f;

        for (size_t c = 0; c < m_channels; ++c) {
            real += m_freq[c][i][0];
            imag += m_freq[c][i][1];
        }

        float sqrmag = (real * real + imag * imag);

        if (m_prevTransientMag[i] > 0.f) {
            float diff = 10.f * log10f(sqrmag / m_prevTransientMag[i]);
            if (diff > 3.f) ++count;
        }

        m_prevTransientMag[i] = sqrmag;
    }

    bool isTransient = false;

//    if (count > m_transientThreshold &&
//        count > m_prevTransientScore * 1.2) {
    if (count > m_prevTransientScore &&
        count > m_transientThreshold &&
        int(count) - m_prevTransientScore > int(m_wlen) / 20) {
        isTransient = true;

#ifdef DEBUG_AUDIO_TIME_STRETCHER
        std::cerr << "isTransient (count = " << count << ", prev = " << m_prevTransientScore << ", diff = " << count - m_prevTransientScore << ", ratio = " << (m_totalCount > 0 ? (float (m_n2sum) / float(m_totalCount * m_n1)) : 1.f) << ", ideal = " << m_ratio << ", nominal = " << getRatio() << ")" << std::endl;
//    } else {
//        std::cerr << " !transient (count = " << count << ", prev = " << m_prevTransientScore << ", diff = " << count - m_prevTransientScore << ")" << std::endl;
#endif
    }

    m_prevTransientScore = count;

    return isTransient;
}

void
AudioTimeStretcher::synthesiseBlock(size_t c,
                                    float *out,
                                    float *modulation,
                                    size_t lastStep)
{
    bool unchanged = (lastStep == m_n1);

    for (size_t i = 0; i <= m_wlen/2; ++i) {

        float phase = princargf(atan2f(m_freq[c][i][1], m_freq[c][i][0]));
        float adjustedPhase = phase;

//        float binfreq = float(m_sampleRate * i) / m_wlen;

        if (!unchanged) {

            float mag = sqrtf(m_freq[c][i][0] * m_freq[c][i][0] +
                              m_freq[c][i][1] * m_freq[c][i][1]);

            float omega = (2 * M_PI * m_n1 * i) / m_wlen;

            float expectedPhase = m_prevPhase[c][i] + omega;

            float phaseError = princargf(phase - expectedPhase);

            float phaseIncrement = (omega + phaseError) / m_n1;

            adjustedPhase = m_prevAdjustedPhase[c][i] +
                lastStep * phaseIncrement;

            float real = mag * cosf(adjustedPhase);
            float imag = mag * sinf(adjustedPhase);
            m_freq[c][i][0] = real;
            m_freq[c][i][1] = imag;
        }

        m_prevPhase[c][i] = phase;
        m_prevAdjustedPhase[c][i] = adjustedPhase;
    }

    fftwf_execute(m_iplan[c]); // m_freq -> m_time, inverse fft

    for (size_t i = 0; i < m_wlen/2; ++i) {
        float temp = m_time[c][i];
        m_time[c][i] = m_time[c][i + m_wlen/2];
        m_time[c][i + m_wlen/2] = temp;
    }

    for (size_t i = 0; i < m_wlen; ++i) {
        m_time[c][i] = m_time[c][i] / m_wlen;
    }

    m_synthesisWindow->cut(m_time[c]);

    for (size_t i = 0; i < m_wlen; ++i) {
        out[i] += m_time[c][i];
    }

    if (modulation) {

        float area = m_analysisWindow->getArea();

        for (size_t i = 0; i < m_wlen; ++i) {
            float val = m_synthesisWindow->getValue(i);
            modulation[i] += val * area;
        }
    }
}


}