Mercurial > hg > svapp

--- a/align/Align.cpp	Thu Apr 23 17:11:26 2020 +0100
+++ b/align/Align.cpp	Fri Apr 24 14:38:22 2020 +0100
@@ -13,661 +13,97 @@
 */

 #include "Align.h"
+#include "TransformAligner.h"
+#include "ExternalProgramAligner.h"
 #include "framework/Document.h"

-#include "data/model/WaveFileModel.h"
-#include "data/model/ReadOnlyWaveFileModel.h"
-#include "data/model/AggregateWaveModel.h"
-#include "data/model/RangeSummarisableTimeValueModel.h"
-#include "data/model/SparseTimeValueModel.h"
-#include "data/model/AlignmentModel.h"
-
-#include "data/fileio/CSVFileReader.h"
-
-#include "transform/TransformFactory.h"
-#include "transform/ModelTransformerFactory.h"
-#include "transform/FeatureExtractionModelTransformer.h"
-
-#include <QProcess>
 #include <QSettings>
-#include <QApplication>

 bool
-Align::alignModel(Document *doc, ModelId ref, ModelId other, QString &error)
+Align::alignModel(Document *doc,
+                  ModelId reference,
+                  ModelId toAlign,
+                  QString &error)
+{
+    bool useProgram;
+    QString program;
+    getAlignerPreference(useProgram, program);
+
+    std::shared_ptr<Aligner> aligner;
+
+    {
+        // Replace the aligner with a new one. This also stops any
+        // previously-running alignment, when the old entry is
+        // replaced and its aligner destroyed.
+
+        QMutexLocker locker(&m_mutex);
+
+        if (useProgram && (program != "")) {
+            m_aligners[toAlign] =
+                std::make_shared<ExternalProgramAligner>(doc,
+                                                         reference,
+                                                         toAlign,
+                                                         program);
+        } else {
+            m_aligners[toAlign] =
+                std::make_shared<TransformAligner>(doc,
+                                                   reference,
+                                                   toAlign);
+        }
+
+        aligner = m_aligners[toAlign];
+    }
+
+    connect(aligner.get(), SIGNAL(complete(ModelId)),
+            this, SLOT(alignerComplete(ModelId)));
+
+    return aligner->begin(error);
+}
+
+void
+Align::getAlignerPreference(bool useProgram, QString program)
 {
     QSettings settings;
     settings.beginGroup("Preferences");
-    bool useProgram = settings.value("use-external-alignment", false).toBool();
-    QString program = settings.value("external-alignment-program", "").toString();
+    useProgram = settings.value("use-external-alignment", false).toBool();
+    program = settings.value("external-alignment-program", "").toString();
     settings.endGroup();
-
-    if (useProgram && (program != "")) {
-        return alignModelViaProgram(doc, ref, other, program, error);
-    } else {
-        return alignModelViaTransform(doc, ref, other, error);
-    }
-}
-
-QString
-Align::getAlignmentTransformName()
-{
-    QSettings settings;
-    settings.beginGroup("Alignment");
-    TransformId id =
-        settings.value("transform-id",
-                       "vamp:match-vamp-plugin:match:path").toString();
-    settings.endGroup();
-    return id;
-}
-
-QString
-Align::getTuningDifferenceTransformName()
-{
-    QSettings settings;
-    settings.beginGroup("Alignment");
-    bool performPitchCompensation =
-        settings.value("align-pitch-aware", false).toBool();
-    QString id = "";
-    if (performPitchCompensation) {
-        id = settings.value
-            ("tuning-difference-transform-id",
-             "vamp:tuning-difference:tuning-difference:tuningfreq")
-            .toString();
-    }
-    settings.endGroup();
-    return id;
 }

 bool
 Align::canAlign()
 {
-    TransformFactory *factory = TransformFactory::getInstance();
-    TransformId id = getAlignmentTransformName();
-    TransformId tdId = getTuningDifferenceTransformName();
-    return factory->haveTransform(id) &&
-        (tdId == "" || factory->haveTransform(tdId));
+    bool useProgram;
+    QString program;
+    getAlignerPreference(useProgram, program);
+
+    if (useProgram) {
+        return ExternalProgramAligner::isAvailable(program);
+    } else {
+        return TransformAligner::isAvailable();
+    }
 }

 void
-Align::abandonOngoingAlignment(ModelId otherId)
+Align::alignerComplete(ModelId alignmentModel)
 {
-    auto other = ModelById::getAs<RangeSummarisableTimeValueModel>(otherId);
-    if (!other) {
+    Aligner *aligner = qobject_cast<Aligner *>(sender());
+    if (!aligner) {
+        SVCERR << "ERROR: Align::alignerComplete: Caller is not an Aligner"
+               << endl;
         return;
     }

-    ModelId alignmentModelId = other->getAlignment();
-    if (alignmentModelId.isNone()) {
-        return;
-    }
+    {
+        QMutexLocker locker (&m_mutex);

-    SVCERR << "Align::abandonOngoingAlignment: An alignment is ongoing for model "
-           << otherId << " (alignment model id " << alignmentModelId
-           << "), abandoning it..." << endl;
-
-    other->setAlignment({});
-
-    for (auto pp: m_pendingProcesses) {
-        if (alignmentModelId == pp.second) {
-            QProcess *process = pp.first;
-            m_pendingProcesses.erase(process);
-            SVCERR << "Align::abandonOngoingAlignment: Killing external "
-                   << "alignment process " << process << "..." << endl;
-            delete process; // kills the process itself
-            break;
+        for (auto p: m_aligners) {
+            if (aligner == p.second.get()) {
+                m_aligners.erase(p.first);
+                break;
+            }
         }
     }

-    if (m_pendingAlignments.find(alignmentModelId) !=
-        m_pendingAlignments.end()) {
-        SVCERR << "Align::abandonOngoingAlignment: Releasing path output model "
-               << m_pendingAlignments[alignmentModelId]
-               << "..." << endl;
-        ModelById::release(m_pendingAlignments[alignmentModelId]);
-        SVCERR << "Align::abandonOngoingAlignment: Dropping alignment model "
-               << alignmentModelId
-               << " from pending alignments..." << endl;
-        m_pendingAlignments.erase(alignmentModelId);
-    }
-
-    for (auto ptd: m_pendingTuningDiffs) {
-        if (alignmentModelId == ptd.second.alignment) {
-            SVCERR << "Align::abandonOngoingAlignment: Releasing preparatory model "
-                   << ptd.second.preparatory << "..." << endl;
-            ModelById::release(ptd.second.preparatory);
-            SVCERR << "Align::abandonOngoingAlignment: Releasing pending tuning-diff model "
-                   << ptd.first << "..." << endl;
-            ModelById::release(ptd.first);
-            SVCERR << "Align::abandonOngoingAlignment: Dropping tuning-diff model "
-                   << ptd.first
-                   << " from pending tuning diffs..." << endl;
-            m_pendingTuningDiffs.erase(ptd.first);
-            break;
-        }
-    }
-
-    SVCERR << "Align::abandonOngoingAlignment: done" << endl;
+    emit alignmentComplete(alignmentModel);
 }
-
-bool
-Align::alignModelViaTransform(Document *doc,
-                              ModelId referenceId,
-                              ModelId otherId,
-                              QString &error)
-{
-    QMutexLocker locker (&m_mutex);
-
-    auto reference =
-        ModelById::getAs<RangeSummarisableTimeValueModel>(referenceId);
-    auto other =
-        ModelById::getAs<RangeSummarisableTimeValueModel>(otherId);
-
-    if (!reference || !other) return false;
-
-    // There may be an alignment already happening; we should stop it,
-    // which we can do by discarding the output models for its
-    // transforms
-    abandonOngoingAlignment(otherId);
-
-    // This involves creating a number of new models:
-    //
-    // 1. an AggregateWaveModel to provide the mixdowns of the main
-    // model and the new model in its two channels, as input to the
-    // MATCH plugin. We just call this one aggregateModel
-    //
-    // 2a. a SparseTimeValueModel which will be automatically created
-    // by FeatureExtractionModelTransformer when running the
-    // TuningDifference plugin to receive the relative tuning of the
-    // second model (if pitch-aware alignment is enabled in the
-    // preferences). We call this tuningDiffOutputModel.
-    //
-    // 2b. a SparseTimeValueModel which will be automatically created
-    // by FeatureExtractionPluginTransformer when running the MATCH
-    // plugin to perform alignment (so containing the alignment path).
-    // We call this one pathOutputModel.
-    //
-    // 2c. a SparseTimeValueModel used solely to provide faked
-    // completion information to the AlignmentModel while a
-    // TuningDifference calculation is going on. We call this
-    // preparatoryModel.
-    //
-    // 3. an AlignmentModel, which stores the path and carries out
-    // alignment lookups on it. We just call this one alignmentModel.
-    //
-    // Models 1 and 3 are registered with the document, which will
-    // eventually release them. We don't release them here except in
-    // the case where an activity fails before the point where we
-    // would otherwise have registered them with the document.
-    //
-    // Models 2a (tuningDiffOutputModel), 2b (pathOutputModel) and 2c
-    // (preparatoryModel) are not registered with the document. Model
-    // 2b (pathOutputModel) is not registered because we do not have a
-    // stable reference to the document at the point where it is
-    // created. Model 2c (preparatoryModel) is not registered because
-    // it is a bodge that we are embarrassed about, so we try to
-    // manage it ourselves without anyone else noticing. Model 2a is
-    // not registered for symmetry with the other two. These have to
-    // be released by us when finished with, but their lifespans do
-    // not extend beyond the end of the alignment procedure, so this
-    // should be ok.
-
-    AggregateWaveModel::ChannelSpecList components;
-
-    components.push_back
-        (AggregateWaveModel::ModelChannelSpec(referenceId, -1));
-
-    components.push_back
-        (AggregateWaveModel::ModelChannelSpec(otherId, -1));
-
-    auto aggregateModel = std::make_shared<AggregateWaveModel>(components);
-    auto aggregateModelId = ModelById::add(aggregateModel);
-    doc->addNonDerivedModel(aggregateModelId);
-
-    auto alignmentModel = std::make_shared<AlignmentModel>
-        (referenceId, otherId, ModelId());
-    auto alignmentModelId = ModelById::add(alignmentModel);
-
-    TransformId tdId = getTuningDifferenceTransformName();
-
-    if (tdId == "") {
-
-        if (beginTransformDrivenAlignment(aggregateModelId,
-                                          alignmentModelId)) {
-            other->setAlignment(alignmentModelId);
-            doc->addNonDerivedModel(alignmentModelId);
-        } else {
-            error = alignmentModel->getError();
-            ModelById::release(alignmentModel);
-            return false;
-        }
-
-    } else {
-
-        // Have a tuning-difference transform id, so run it
-        // asynchronously first
-
-        TransformFactory *tf = TransformFactory::getInstance();
-
-        Transform transform = tf->getDefaultTransformFor
-            (tdId, aggregateModel->getSampleRate());
-
-        transform.setParameter("maxduration", 60);
-        transform.setParameter("maxrange", 6);
-        transform.setParameter("finetuning", false);
-
-        SVDEBUG << "Align::alignModel: Tuning difference transform step size " << transform.getStepSize() << ", block size " << transform.getBlockSize() << endl;
-
-        ModelTransformerFactory *mtf = ModelTransformerFactory::getInstance();
-
-        QString message;
-        ModelId tuningDiffOutputModelId = mtf->transform(transform,
-                                                         aggregateModelId,
-                                                         message);
-
-        auto tuningDiffOutputModel =
-            ModelById::getAs<SparseTimeValueModel>(tuningDiffOutputModelId);
-        if (!tuningDiffOutputModel) {
-            SVCERR << "Align::alignModel: ERROR: Failed to create tuning-difference output model (no Tuning Difference plugin?)" << endl;
-            error = message;
-            ModelById::release(alignmentModel);
-            return false;
-        }
-
-        other->setAlignment(alignmentModelId);
-        doc->addNonDerivedModel(alignmentModelId);
-
-        connect(tuningDiffOutputModel.get(),
-                SIGNAL(completionChanged(ModelId)),
-                this, SLOT(tuningDifferenceCompletionChanged(ModelId)));
-
-        TuningDiffRec rec;
-        rec.input = aggregateModelId;
-        rec.alignment = alignmentModelId;
-
-        // This model exists only so that the AlignmentModel can get a
-        // completion value from somewhere while the tuning difference
-        // calculation is going on
-        auto preparatoryModel = std::make_shared<SparseTimeValueModel>
-            (aggregateModel->getSampleRate(), 1);
-        auto preparatoryModelId = ModelById::add(preparatoryModel);
-        preparatoryModel->setCompletion(0);
-        rec.preparatory = preparatoryModelId;
-        alignmentModel->setPathFrom(rec.preparatory);
-
-        m_pendingTuningDiffs[tuningDiffOutputModelId] = rec;
-
-        SVDEBUG << "Align::alignModelViaTransform: Made a note of pending tuning diff output model id " << tuningDiffOutputModelId << " with input " << rec.input << ", alignment model " << rec.alignment << ", preparatory model " << rec.preparatory << endl;
-    }
-
-    return true;
-}
-
-void
-Align::tuningDifferenceCompletionChanged(ModelId tuningDiffOutputModelId)
-{
-    QMutexLocker locker(&m_mutex);
-
-    if (m_pendingTuningDiffs.find(tuningDiffOutputModelId) ==
-        m_pendingTuningDiffs.end()) {
-        SVDEBUG << "NOTE: Align::tuningDifferenceCompletionChanged: Model "
-                << tuningDiffOutputModelId
-                << " not found in pending tuning diff map, presuming "
-                << "completed or abandoned" << endl;
-        return;
-    }
-
-    auto tuningDiffOutputModel =
-        ModelById::getAs<SparseTimeValueModel>(tuningDiffOutputModelId);
-    if (!tuningDiffOutputModel) {
-        SVCERR << "WARNING: Align::tuningDifferenceCompletionChanged: Model "
-               << tuningDiffOutputModelId
-               << " not known as SparseTimeValueModel" << endl;
-        return;
-    }
-
-    TuningDiffRec rec = m_pendingTuningDiffs[tuningDiffOutputModelId];
-
-    auto alignmentModel = ModelById::getAs<AlignmentModel>(rec.alignment);
-    if (!alignmentModel) {
-        SVCERR << "WARNING: Align::tuningDifferenceCompletionChanged:"
-               << "alignment model has disappeared" << endl;
-        return;
-    }
-
-    int completion = 0;
-    bool done = tuningDiffOutputModel->isReady(&completion);
-
-    if (!done) {
-        // This will be the completion the alignment model reports,
-        // before the alignment actually begins. It goes up from 0 to
-        // 99 (not 100!) and then back to 0 again when we start
-        // calculating the actual path in the following phase
-        int clamped = (completion == 100 ? 99 : completion);
-        auto preparatoryModel =
-            ModelById::getAs<SparseTimeValueModel>(rec.preparatory);
-        if (preparatoryModel) {
-            preparatoryModel->setCompletion(clamped);
-        }
-        return;
-    }
-
-    float tuningFrequency = 440.f;
-
-    if (!tuningDiffOutputModel->isEmpty()) {
-        tuningFrequency = tuningDiffOutputModel->getAllEvents()[0].getValue();
-        SVCERR << "Align::tuningDifferenceCompletionChanged: Reported tuning frequency = " << tuningFrequency << endl;
-    } else {
-        SVCERR << "Align::tuningDifferenceCompletionChanged: No tuning frequency reported" << endl;
-    }
-
-    ModelById::release(tuningDiffOutputModel);
-
-    alignmentModel->setPathFrom({}); // replace preparatoryModel
-    ModelById::release(rec.preparatory);
-    rec.preparatory = {};
-
-    m_pendingTuningDiffs.erase(tuningDiffOutputModelId);
-
-    SVDEBUG << "Align::tuningDifferenceCompletionChanged: Erasing model "
-            << tuningDiffOutputModelId << " from pending tuning diffs and "
-            << "launching the alignment phase for alignment model "
-            << rec.alignment << " with tuning frequency "
-            << tuningFrequency << endl;
-
-    beginTransformDrivenAlignment
-        (rec.input, rec.alignment, tuningFrequency);
-}
-
-bool
-Align::beginTransformDrivenAlignment(ModelId aggregateModelId,
-                                     ModelId alignmentModelId,
-                                     float tuningFrequency)
-{
-    TransformId id = getAlignmentTransformName();
-
-    TransformFactory *tf = TransformFactory::getInstance();
-
-    auto aggregateModel =
-        ModelById::getAs<AggregateWaveModel>(aggregateModelId);
-    auto alignmentModel =
-        ModelById::getAs<AlignmentModel>(alignmentModelId);
-
-    if (!aggregateModel || !alignmentModel) {
-        SVCERR << "Align::alignModel: ERROR: One or other of the aggregate & alignment models has disappeared" << endl;
-        return false;
-    }
-
-    Transform transform = tf->getDefaultTransformFor
-        (id, aggregateModel->getSampleRate());
-
-    transform.setStepSize(transform.getBlockSize()/2);
-    transform.setParameter("serialise", 1);
-    transform.setParameter("smooth", 0);
-    transform.setParameter("zonewidth", 40);
-    transform.setParameter("noise", true);
-    transform.setParameter("minfreq", 500);
-
-    int cents = 0;
-
-    if (tuningFrequency != 0.f) {
-        transform.setParameter("freq2", tuningFrequency);
-
-        double centsOffset = 0.f;
-        int pitch = Pitch::getPitchForFrequency(tuningFrequency, &centsOffset);
-        cents = int(round((pitch - 69) * 100 + centsOffset));
-        SVCERR << "frequency " << tuningFrequency << " yields cents offset " << centsOffset << " and pitch " << pitch << " -> cents " << cents << endl;
-    }
-
-    alignmentModel->setRelativePitch(cents);
-
-    SVDEBUG << "Align::alignModel: Alignment transform step size " << transform.getStepSize() << ", block size " << transform.getBlockSize() << endl;
-
-    ModelTransformerFactory *mtf = ModelTransformerFactory::getInstance();
-
-    QString message;
-    ModelId pathOutputModelId = mtf->transform
-        (transform, aggregateModelId, message);
-
-    if (pathOutputModelId.isNone()) {
-        transform.setStepSize(0);
-        pathOutputModelId = mtf->transform
-            (transform, aggregateModelId, message);
-    }
-
-    auto pathOutputModel =
-        ModelById::getAs<SparseTimeValueModel>(pathOutputModelId);
-
-    //!!! callers will need to be updated to get error from
-    //!!! alignment model after initial call
-
-    if (!pathOutputModel) {
-        SVCERR << "Align::alignModel: ERROR: Failed to create alignment path (no MATCH plugin?)" << endl;
-        alignmentModel->setError(message);
-        return false;
-    }
-
-    pathOutputModel->setCompletion(0);
-    alignmentModel->setPathFrom(pathOutputModelId);
-
-    m_pendingAlignments[alignmentModelId] = pathOutputModelId;
-
-    connect(alignmentModel.get(), SIGNAL(completionChanged(ModelId)),
-            this, SLOT(alignmentCompletionChanged(ModelId)));
-
-    return true;
-}
-
-void
-Align::alignmentCompletionChanged(ModelId alignmentModelId)
-{
-    QMutexLocker locker (&m_mutex);
-
-    auto alignmentModel = ModelById::getAs<AlignmentModel>(alignmentModelId);
-
-    if (alignmentModel && alignmentModel->isReady()) {
-
-        if (m_pendingAlignments.find(alignmentModelId) !=
-            m_pendingAlignments.end()) {
-            ModelId pathOutputModelId = m_pendingAlignments[alignmentModelId];
-            ModelById::release(pathOutputModelId);
-            m_pendingAlignments.erase(alignmentModelId);
-        }
-
-        disconnect(alignmentModel.get(),
-                   SIGNAL(completionChanged(ModelId)),
-                   this, SLOT(alignmentCompletionChanged(ModelId)));
-        emit alignmentComplete(alignmentModelId);
-    }
-}
-
-bool
-Align::alignModelViaProgram(Document *doc,
-                            ModelId referenceId,
-                            ModelId otherId,
-                            QString program,
-                            QString &error)
-{
-    // Run an external program, passing to it paths to the main
-    // model's audio file and the new model's audio file. It returns
-    // the path in CSV form through stdout.
-
-    auto reference = ModelById::getAs<ReadOnlyWaveFileModel>(referenceId);
-    auto other = ModelById::getAs<ReadOnlyWaveFileModel>(otherId);
-    if (!reference || !other) {
-        SVCERR << "ERROR: Align::alignModelViaProgram: Can't align non-read-only models via program (no local filename available)" << endl;
-        return false;
-    }
-
-    while (!reference->isReady(nullptr) || !other->isReady(nullptr)) {
-        qApp->processEvents();
-    }
-
-    QString refPath = reference->getLocalFilename();
-    if (refPath == "") {
-        refPath = FileSource(reference->getLocation()).getLocalFilename();
-    }
-
-    QString otherPath = other->getLocalFilename();
-    if (otherPath == "") {
-        otherPath = FileSource(other->getLocation()).getLocalFilename();
-    }
-
-    if (refPath == "" || otherPath == "") {
-        error = "Failed to find local filepath for wave-file model";
-        return false;
-    }
-
-    QProcess *process = nullptr;
-    ModelId alignmentModelId = {};
-
-    {
-        QMutexLocker locker (&m_mutex);
-
-        auto alignmentModel =
-            std::make_shared<AlignmentModel>(referenceId, otherId, ModelId());
-
-        alignmentModelId = ModelById::add(alignmentModel);
-        other->setAlignment(alignmentModelId);
-
-        process = new QProcess;
-        process->setProcessChannelMode(QProcess::ForwardedErrorChannel);
-
-        connect(process,
-                SIGNAL(finished(int, QProcess::ExitStatus)),
-                this,
-                SLOT(alignmentProgramFinished(int, QProcess::ExitStatus)));
-
-        m_pendingProcesses[process] = alignmentModelId;
-    }
-
-    QStringList args;
-    args << refPath << otherPath;
-
-    SVCERR << "Align::alignModelViaProgram: Starting program \""
-           << program << "\" with args: ";
-    for (auto a: args) {
-        SVCERR << "\"" << a << "\" ";
-    }
-    SVCERR << endl;
-
-    process->start(program, args);
-
-    bool success = process->waitForStarted();
-
-    {
-        QMutexLocker locker(&m_mutex);
-
-        if (!success) {
-
-            SVCERR << "ERROR: Align::alignModelViaProgram: "
-                   << "Program did not start" << endl;
-            error = "Alignment program \"" + program + "\" did not start";
-
-            m_pendingProcesses.erase(process);
-            other->setAlignment({});
-            ModelById::release(alignmentModelId);
-            delete process;
-
-        } else {
-            doc->addNonDerivedModel(alignmentModelId);
-        }
-    }
-
-    return success;
-}
-
-void
-Align::alignmentProgramFinished(int exitCode, QProcess::ExitStatus status)
-{
-    QMutexLocker locker (&m_mutex);
-
-    SVCERR << "Align::alignmentProgramFinished" << endl;
-
-    QProcess *process = qobject_cast<QProcess *>(sender());
-
-    if (m_pendingProcesses.find(process) == m_pendingProcesses.end()) {
-        SVCERR << "ERROR: Align::alignmentProgramFinished: Process " << process
-               << " not found in process model map!" << endl;
-        return;
-    }
-
-    ModelId alignmentModelId = m_pendingProcesses[process];
-    auto alignmentModel = ModelById::getAs<AlignmentModel>(alignmentModelId);
-    if (!alignmentModel) return;
-
-    if (exitCode == 0 && status == 0) {
-
-        CSVFormat format;
-        format.setModelType(CSVFormat::TwoDimensionalModel);
-        format.setTimingType(CSVFormat::ExplicitTiming);
-        format.setTimeUnits(CSVFormat::TimeSeconds);
-        format.setColumnCount(2);
-        // The output format has time in the reference file first, and
-        // time in the "other" file in the second column. This is a
-        // more natural approach for a command-line alignment tool,
-        // but it's the opposite of what we expect for native
-        // alignment paths, which map from "other" file to
-        // reference. These column purpose settings reflect that.
-        format.setColumnPurpose(1, CSVFormat::ColumnStartTime);
-        format.setColumnPurpose(0, CSVFormat::ColumnValue);
-        format.setAllowQuoting(false);
-        format.setSeparator(',');
-
-        CSVFileReader reader(process, format, alignmentModel->getSampleRate());
-        if (!reader.isOK()) {
-            SVCERR << "ERROR: Align::alignmentProgramFinished: Failed to parse output"
-                   << endl;
-            alignmentModel->setError
-                (QString("Failed to parse output of program: %1")
-                 .arg(reader.getError()));
-            goto done;
-        }
-
-        //!!! to use ById?
-
-        Model *csvOutput = reader.load();
-
-        SparseTimeValueModel *path =
-            qobject_cast<SparseTimeValueModel *>(csvOutput);
-        if (!path) {
-            SVCERR << "ERROR: Align::alignmentProgramFinished: Output did not convert to sparse time-value model"
-                   << endl;
-            alignmentModel->setError
-                ("Output of program did not produce sparse time-value model");
-            delete csvOutput;
-            goto done;
-        }
-
-        if (path->isEmpty()) {
-            SVCERR << "ERROR: Align::alignmentProgramFinished: Output contained no mappings"
-                   << endl;
-            alignmentModel->setError
-                ("Output of alignment program contained no mappings");
-            delete path;
-            goto done;
-        }
-
-        SVCERR << "Align::alignmentProgramFinished: Setting alignment path ("
-             << path->getEventCount() << " point(s))" << endl;
-
-        auto pathId =
-            ModelById::add(std::shared_ptr<SparseTimeValueModel>(path));
-        alignmentModel->setPathFrom(pathId);
-
-        emit alignmentComplete(alignmentModelId);
-
-        ModelById::release(pathId);
-
-    } else {
-        SVCERR << "ERROR: Align::alignmentProgramFinished: Aligner program "
-               << "failed: exit code " << exitCode << ", status " << status
-               << endl;
-        alignmentModel->setError
-            ("Aligner process returned non-zero exit status");
-    }
-
-done:
-    m_pendingProcesses.erase(process);
-    delete process;
-}
-
--- a/align/Align.h	Thu Apr 23 17:11:26 2020 +0100
+++ b/align/Align.h	Fri Apr 24 14:38:22 2020 +0100
@@ -21,11 +21,9 @@
 #include <QMutex>
 #include <set>

-#include "data/model/Model.h"
+#include "Aligner.h"

 class AlignmentModel;
-class SparseTimeValueModel;
-class AggregateWaveModel;
 class Document;

 class Align : public QObject
@@ -66,17 +64,6 @@
                     ModelId reference,
                     ModelId toAlign,
                     QString &error);
-
-    bool alignModelViaTransform(Document *doc,
-                                ModelId reference,
-                                ModelId toAlign,
-                                QString &error);
-
-    bool alignModelViaProgram(Document *doc,
-                              ModelId reference,
-                              ModelId toAlign,
-                              QString program,
-                              QString &error);

     /**
      * Return true if the alignment facility is available (relevant
@@ -93,38 +80,18 @@
     void alignmentComplete(ModelId alignmentModel); // an AlignmentModel

 private slots:
-    void alignmentCompletionChanged(ModelId);
-    void tuningDifferenceCompletionChanged(ModelId);
-    void alignmentProgramFinished(int, QProcess::ExitStatus);
+    void alignerComplete(ModelId alignmentModel); // an AlignmentModel

 private:
-    static QString getAlignmentTransformName();
-    static QString getTuningDifferenceTransformName();
-
-    bool beginTransformDrivenAlignment(ModelId, // an AggregateWaveModel
-                                       ModelId, // an AlignmentModel
-                                       float tuningFrequency = 0.f);
-
-    void abandonOngoingAlignment(ModelId otherId);
-
     QMutex m_mutex;

-    struct TuningDiffRec {
-        ModelId input; // an AggregateWaveModel
-        ModelId alignment; // an AlignmentModel
-        ModelId preparatory; // a SparseTimeValueModel
-    };
-
-    // tuning-difference output model (a SparseTimeValueModel) -> data
-    // needed for subsequent alignment
-    std::map<ModelId, TuningDiffRec> m_pendingTuningDiffs;
+    // maps toAlign -> aligner for ongoing alignment - note that
+    // although we can calculate alignments with different references,
+    // we can only have one alignment on any given toAlign model, so
+    // we don't key this on the whole (reference, toAlign) pair
+    std::map<ModelId, std::shared_ptr<Aligner>> m_aligners;

-    // alignment model id -> path output model id
-    std::map<ModelId, ModelId> m_pendingAlignments;
-
-    // external alignment subprocess -> model into which to stuff the
-    // results (an AlignmentModel)
-    std::map<QProcess *, ModelId> m_pendingProcesses;
+    static void getAlignerPreference(bool useProgram, QString program);
 };

 #endif
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/align/Aligner.h	Fri Apr 24 14:38:22 2020 +0100
@@ -0,0 +1,39 @@
+/* -*- 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.
+*/
+
+#ifndef SV_ALIGNER_H
+#define SV_ALIGNER_H
+
+#include <QString>
+
+#include "data/model/Model.h"
+
+class Aligner : public QObject
+{
+    Q_OBJECT
+
+public:
+    virtual ~Aligner() { }
+
+    virtual bool begin(QString &error) = 0;
+
+signals:
+    /**
+     * Emitted when alignment is successfully completed. The reference
+     * and toAlign models can be queried from the alignment model.
+     */
+    void complete(ModelId alignmentModel); // an AlignmentModel
+};
+
+#endif
--- a/align/ExternalProgramAligner.h	Thu Apr 23 17:11:26 2020 +0100
+++ b/align/ExternalProgramAligner.h	Fri Apr 24 14:38:22 2020 +0100
@@ -15,15 +15,15 @@
 #ifndef SV_EXTERNAL_PROGRAM_ALIGNER_H
 #define SV_EXTERNAL_PROGRAM_ALIGNER_H

+#include "Aligner.h"
+
 #include <QProcess>
 #include <QString>

-#include "data/model/Model.h"
-
 class AlignmentModel;
 class Document;

-class ExternalProgramAligner : public QObject
+class ExternalProgramAligner : public Aligner
 {
     Q_OBJECT

@@ -36,16 +36,9 @@
     // Destroy the aligner, cleanly cancelling any ongoing alignment
     ~ExternalProgramAligner();

-    bool begin(QString &error);
+    bool begin(QString &error) override;

     static bool isAvailable(QString program);
-
-signals:
-    /**
-     * Emitted when alignment is successfully completed. The reference
-     * and toAlign models can be queried from the alignment model.
-     */
-    void complete(ModelId alignmentModel); // an AlignmentModel

 private slots:
     void programFinished(int, QProcess::ExitStatus);
--- a/align/TransformAligner.cpp	Thu Apr 23 17:11:26 2020 +0100
+++ b/align/TransformAligner.cpp	Fri Apr 24 14:38:22 2020 +0100
@@ -189,12 +189,12 @@
         ModelTransformerFactory *mtf = ModelTransformerFactory::getInstance();

         QString message;
-        ModelId tuningDiffOutputModelId = mtf->transform(transform,
-                                                         m_aggregateModel,
-                                                         message);
+        m_tuningDiffOutputModel = mtf->transform(transform,
+                                                 m_aggregateModel,
+                                                 message);

         auto tuningDiffOutputModel =
-            ModelById::getAs<SparseTimeValueModel>(tuningDiffOutputModelId);
+            ModelById::getAs<SparseTimeValueModel>(m_tuningDiffOutputModel);
         if (!tuningDiffOutputModel) {
             SVCERR << "Align::alignModel: ERROR: Failed to create tuning-difference output model (no Tuning Difference plugin?)" << endl;
             error = message;
@@ -227,8 +227,9 @@
 {
     if (tuningDiffOutputModelId != m_tuningDiffOutputModel) {
         SVCERR << "WARNING: TransformAligner::tuningDifferenceCompletionChanged: Model "
-                << tuningDiffOutputModelId
-                << " is not ours!" << endl;
+               << tuningDiffOutputModelId
+               << " is not ours! (ours is "
+               << m_tuningDiffOutputModel << ")" << endl;
         return;
     }

@@ -289,6 +290,9 @@
 {
     TransformId id = getAlignmentTransformName();

+    SVDEBUG << "TransformAligner::beginAlignmentPhase: transform is "
+            << id << endl;
+
     TransformFactory *tf = TransformFactory::getInstance();

     auto aggregateModel =
@@ -327,24 +331,24 @@

     alignmentModel->setRelativePitch(cents);

-    SVDEBUG << "Align::alignModel: Alignment transform step size "
+    SVDEBUG << "TransformAligner: Alignment transform step size "
             << transform.getStepSize() << ", block size "
             << transform.getBlockSize() << endl;

     ModelTransformerFactory *mtf = ModelTransformerFactory::getInstance();

     QString message;
-    ModelId pathOutputModelId = mtf->transform
+    m_pathOutputModel = mtf->transform
         (transform, m_aggregateModel, message);

-    if (pathOutputModelId.isNone()) {
+    if (m_pathOutputModel.isNone()) {
         transform.setStepSize(0);
-        pathOutputModelId = mtf->transform
+        m_pathOutputModel = mtf->transform
             (transform, m_aggregateModel, message);
     }

     auto pathOutputModel =
-        ModelById::getAs<SparseTimeValueModel>(pathOutputModelId);
+        ModelById::getAs<SparseTimeValueModel>(m_pathOutputModel);

     //!!! callers will need to be updated to get error from
     //!!! alignment model after initial call
@@ -369,8 +373,9 @@
 {
     if (alignmentModelId != m_alignmentModel) {
         SVCERR << "WARNING: TransformAligner::alignmentCompletionChanged: Model "
-                << alignmentModelId
-                << " is not ours!" << endl;
+               << alignmentModelId
+               << " is not ours! (ours is "
+               << m_alignmentModel << ")" << endl;
         return;
     }
--- a/align/TransformAligner.h	Thu Apr 23 17:11:26 2020 +0100
+++ b/align/TransformAligner.h	Fri Apr 24 14:38:22 2020 +0100
@@ -15,14 +15,12 @@
 #ifndef SV_TRANSFORM_ALIGNER_H
 #define SV_TRANSFORM_ALIGNER_H

-#include <QString>
-
-#include "data/model/Model.h"
+#include "Aligner.h"

 class AlignmentModel;
 class Document;

-class TransformAligner : public QObject
+class TransformAligner : public Aligner
 {
     Q_OBJECT

@@ -34,17 +32,10 @@
     // Destroy the aligner, cleanly cancelling any ongoing alignment
     ~TransformAligner();

-    bool begin(QString &error);
+    bool begin(QString &error) override;

     static bool isAvailable();

-signals:
-    /**
-     * Emitted when alignment is successfully completed. The reference
-     * and toAlign models can be queried from the alignment model.
-     */
-    void complete(ModelId alignmentModel); // an AlignmentModel
-
 private slots:
     void alignmentCompletionChanged(ModelId);
     void tuningDifferenceCompletionChanged(ModelId);
--- a/files.pri	Thu Apr 23 17:11:26 2020 +0100
+++ b/files.pri	Fri Apr 24 14:38:22 2020 +0100
@@ -1,6 +1,7 @@

 SVAPP_HEADERS += \
            align/Align.h \
+           align/Aligner.h \
            align/ExternalProgramAligner.h \
            align/TransformAligner.h \
            audio/AudioCallbackPlaySource.h \