diff audio/TimeStretchWrapper.cpp @ 738:48001ed9143b audio-source-refactor

Introduce TimeStretchWrapper; some work towards making the AudioCallbackPlaySource not actually try to be an ApplicationPlaybackSource itself but only return one that is constructed from wrappers that it controls the lifespan of

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/audio/TimeStretchWrapper.cpp	Wed Mar 18 12:51:41 2020 +0000
@@ -0,0 +1,228 @@
+/* -*- 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 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 "TimeStretchWrapper.h"
+
+#include <rubberband/RubberBandStretcher.h>
+
+#include "base/Debug.h"
+
+using namespace RubberBand;
+using namespace std;
+
+TimeStretchWrapper::TimeStretchWrapper(ApplicationPlaybackSource *source) :
+    m_source(source),
+    m_stretcher(nullptr),
+    m_timeRatio(1.0),
+    m_stretcherInputSize(16384),
+    m_channelCount(0),
+    m_sampleRate(0)
+{
+}
+
+TimeStretchWrapper::~TimeStretchWrapper()
+{
+    delete m_stretcher;
+}
+
+void
+TimeStretchWrapper::setTimeStretchRatio(double ratio)
+{
+    lock_guard<mutex> guard(m_mutex);
+
+    SVDEBUG << "TimeStretchWrapper::setTimeStretchRatio: setting ratio to "
+            << ratio << " (was " << m_timeRatio << ")" << endl;
+    
+    m_timeRatio = ratio;
+
+    // Stretcher will be updated by checkStretcher() from next call to
+    // getSourceSamples()
+}
+
+void
+TimeStretchWrapper::reset()
+{
+    lock_guard<mutex> guard(m_mutex);
+
+    if (m_stretcher) {
+        m_stretcher->reset();
+    }
+}
+
+int
+TimeStretchWrapper::getSourceSamples(float *const *samples,
+                                     int nchannels, int nframes)
+{
+    checkStretcher();
+
+    lock_guard<mutex> guard(m_mutex);
+
+    static int warnings = 0;
+    if (nchannels != m_channelCount) {
+        if (warnings >= 0) {
+            SVCERR << "WARNING: getSourceSamples called for a number of channels different from that set with setSystemPlaybackChannelCount ("
+                   << nchannels << " vs " << m_channelCount << ")" << endl;
+            if (++warnings == 6) {
+                SVCERR << "(further warnings will be suppressed)" << endl;
+                warnings = -1;
+            }
+        }
+        return 0;
+    }
+    
+    if (!m_stretcher) {
+        return m_source->getSourceSamples(samples, nchannels, nframes);
+    }
+
+    sv_frame_t available;
+    sv_frame_t fedToStretcher = 0;
+
+    vector<float *> inputPtrs(m_channelCount, nullptr);
+    for (int i = 0; i < m_channelCount; ++i) {
+        inputPtrs[i] = m_inputs[i].data();
+    }
+    
+    // The input block for a given output is approx output / ratio,
+    // but we can't predict it exactly, for an adaptive timestretcher.
+
+    while ((available = m_stretcher->available()) < nframes) {
+        
+        sv_frame_t reqd = sv_frame_t
+            (ceil(double(nframes - available) / m_timeRatio));
+        reqd = std::max(reqd, sv_frame_t(m_stretcher->getSamplesRequired()));
+        reqd = std::min(reqd, m_stretcherInputSize);
+        if (reqd == 0) reqd = 1;
+        
+        int got = m_source->getSourceSamples
+            (inputPtrs.data(), nchannels, reqd);
+
+        if (got <= 0) {
+            SVCERR << "WARNING: Failed to obtain any source samples at all"
+                   << endl;
+            return 0;
+        }
+            
+        m_stretcher->process
+            (inputPtrs.data(), size_t(got), false);
+    }
+
+    return int(m_stretcher->retrieve(samples, nframes));
+}
+
+void
+TimeStretchWrapper::checkStretcher()
+{
+    lock_guard<mutex> guard(m_mutex);
+
+    if (m_timeRatio == 1.0 || !m_channelCount || !m_sampleRate) {
+        SVDEBUG << "TimeStretchWrapper::checkStretcher: m_timeRatio = "
+                << m_timeRatio << ", m_channelCount = " << m_channelCount
+                << ", m_sampleRate = " << m_sampleRate
+                << ", no need for stretcher" << endl;
+        if (m_stretcher) {
+            SVDEBUG << "(Deleting existing one)" << endl;
+            delete m_stretcher;
+            m_stretcher = nullptr;
+        }
+        return;
+    }
+    
+    if (m_stretcher) {
+        SVDEBUG << "TimeStretchWrapper::checkStretcher: setting stretcher ratio to " << m_timeRatio << endl;
+        m_stretcher->setTimeRatio(m_timeRatio);
+        return;
+    }
+
+    SVDEBUG << "TimeStretchWrapper::checkStretcher: creating stretcher with ratio " << m_timeRatio << endl;
+    
+    m_stretcher = new RubberBandStretcher
+        (m_sampleRate,
+         m_channelCount,
+         RubberBandStretcher::OptionProcessRealTime,
+         m_timeRatio);
+
+    m_inputs.resize(m_channelCount);
+    for (auto &v: m_inputs) {
+        v.resize(m_stretcherInputSize);
+    }
+}
+
+void
+TimeStretchWrapper::setSystemPlaybackChannelCount(int count)
+{
+    {
+        lock_guard<mutex> guard(m_mutex);
+        if (m_channelCount != count) {
+            delete m_stretcher;
+            m_stretcher = nullptr;
+        }
+        m_channelCount = count;
+    }
+    m_source->setSystemPlaybackChannelCount(count);
+}
+
+void
+TimeStretchWrapper::setSystemPlaybackSampleRate(int rate)
+{
+    {
+        lock_guard<mutex> guard(m_mutex);
+        if (m_sampleRate != rate) {
+            delete m_stretcher;
+            m_stretcher = nullptr;
+        }
+        m_sampleRate = rate;
+    }
+    m_source->setSystemPlaybackSampleRate(rate);
+}
+
+std::string
+TimeStretchWrapper::getClientName() const
+{
+    return m_source->getClientName();
+}
+
+int
+TimeStretchWrapper::getApplicationSampleRate() const
+{
+    return m_source->getApplicationSampleRate();
+}
+
+int
+TimeStretchWrapper::getApplicationChannelCount() const
+{
+    return m_source->getApplicationChannelCount();
+}
+
+void
+TimeStretchWrapper::setSystemPlaybackBlockSize(int)
+{
+}
+
+void
+TimeStretchWrapper::setSystemPlaybackLatency(int latency)
+{
+    m_source->setSystemPlaybackLatency(latency);
+}
+
+void
+TimeStretchWrapper::setOutputLevels(float left, float right)
+{
+    m_source->setOutputLevels(left, right);
+}
+
+void
+TimeStretchWrapper::audioProcessingOverload()
+{
+    m_source->audioProcessingOverload();
+}