diff --git a/oscar/tests/prs1tests.cpp b/oscar/tests/prs1tests.cpp
index f1cfd470..8b282de4 100644
--- a/oscar/tests/prs1tests.cpp
+++ b/oscar/tests/prs1tests.cpp
@@ -13,6 +13,7 @@
 
 static PRS1Loader* s_loader = nullptr;
 static void iterateTestCards(const QString & root, void (*action)(const QString &));
+static QString prs1OutputPath(const QString & inpath, const QString & serial, const QString & basename, const QString & suffix);
 static QString prs1OutputPath(const QString & inpath, const QString & serial, int session, const QString & suffix);
 
 void PRS1Tests::initTestCase(void)
@@ -74,9 +75,166 @@ void PRS1Tests::testSessionsToYaml()
 }
 
 
+// ====================================================================================================
+
+static QString ts(qint64 msecs)
+{
+    return QDateTime::fromMSecsSinceEpoch(msecs).toString(Qt::ISODate);
+}
+
+static QString byteList(QByteArray data)
+{
+    QStringList l;
+    for (int i = 0; i < data.size(); i++) {
+        l.push_back(QString( "%1" ).arg((int) data[i] & 0xFF, 2, 16, QChar('0') ).toUpper());
+    }
+    QString s = l.join("");
+    return s;
+}
+
+void ChunkToYaml(QFile & file, PRS1DataChunk* chunk)
+{
+    QTextStream out(&file);
+
+    // chunk header
+    out << "chunk:" << endl;
+    out << "  at: " << hex << chunk->m_filepos << endl;
+    out << "  version: " << dec << chunk->fileVersion << endl;
+    out << "  size: " << chunk->blockSize << endl;
+    out << "  htype: " << chunk->htype << endl;
+    out << "  family: " << chunk->family << endl;
+    out << "  familyVersion: " << chunk->familyVersion << endl;
+    out << "  ext: " << chunk->ext << endl;
+    out << "  session: " << chunk->sessionid << endl;
+    out << "  start: " << ts(chunk->timestamp * 1000L) << endl;
+
+    // hblock for V3 non-waveform chunks
+    if (chunk->fileVersion == 3 && chunk->htype == 0) {
+        out << "  hblock:" << endl;
+        QMapIterator<unsigned char, short> i(chunk->hblock);
+        while (i.hasNext()) {
+            i.next();
+            out << "    " << (int) i.key() << ": " << i.value() << endl;
+        }
+    }
+
+    // waveform chunks
+    if (chunk->htype == 1) {
+        out << "  intervals: " << chunk->interval_count << endl;
+        out << "  intervalSeconds: " << (int) chunk->interval_seconds << endl;
+        out << "  interleave:" << endl;
+        for (int i=0; i < chunk->waveformInfo.size(); i++) {
+            const PRS1Waveform & w = chunk->waveformInfo.at(i);
+            out << "    " << i << ": " << w.interleave << endl;
+        }
+        out << "  end: " << ts((chunk->timestamp + chunk->duration) * 1000L) << endl;
+    }
+    
+    // header checksum
+    out << "  checksum: " << hex << chunk->storedChecksum << endl;
+    if (chunk->storedChecksum != chunk->calcChecksum) {
+        out << "  calcChecksum: " << hex << chunk->calcChecksum << endl;
+    }
+    
+    // data
+    out << "  data: " << byteList(chunk->m_data) << endl;
+    
+    // data CRC
+    out << "  crc: " << hex << chunk->storedCrc << endl;
+    if (chunk->storedCrc != chunk->calcCrc) {
+        out << "  calcCrc: " << hex << chunk->calcCrc << endl;
+    }
+    out << endl;
+}
+
+void parseAndEmitChunkYaml(const QString & path)
+{
+    qDebug() << path;
+
+    QStringList paths;
+    QString propertyfile;
+    int sessionid_base;
+    sessionid_base = s_loader->FindSessionDirsAndProperties(path, paths, propertyfile);
+
+    Machine *m = s_loader->CreateMachineFromProperties(propertyfile);
+    Q_ASSERT(m != nullptr);
+
+    // This mirrors the functional bits of PRS1Loader::ScanFiles.
+    
+    QDir dir;
+    dir.setFilter(QDir::NoDotAndDotDot | QDir::Dirs | QDir::Files | QDir::Hidden | QDir::NoSymLinks);
+    dir.setSorting(QDir::Name);
+
+    int size = paths.size();
+
+    // for each p0/p1/p2/etc... folder
+    for (int p=0; p < size; ++p) {
+        dir.setPath(paths.at(p));
+        if (!dir.exists() || !dir.isReadable()) {
+            qWarning() << dir.canonicalPath() << "can't read directory";
+            continue;
+        }
+        QFileInfoList flist = dir.entryInfoList();
+
+        // Scan for individual .00X files
+        for (int i = 0; i < flist.size(); i++) {
+            QFileInfo fi = flist.at(i);
+            QString inpath = fi.canonicalFilePath();
+            bool ok;
+
+            QString ext_s = fi.fileName().section(".", -1);
+            ext_s.toInt(&ok);
+            if (!ok) {
+                // not a numerical extension
+                qWarning() << inpath << "unexpected filename";
+                continue;
+            }
+
+            QString session_s = fi.fileName().section(".", 0, -2);
+            session_s.toInt(&ok, sessionid_base);
+            if (!ok) {
+                // not a numerical session ID
+                qWarning() << inpath << "unexpected filename";
+                continue;
+            }
+            
+            // Create the YAML file.
+            QString outpath = prs1OutputPath(path, m->serial(), fi.fileName(), "-chunks.yml");
+            QFile file(outpath);
+            if (!file.open(QFile::WriteOnly | QFile::Truncate)) {
+                qDebug() << outpath;
+                Q_ASSERT(false);
+            }
+
+            // Parse the chunks in the file.
+            QList<PRS1DataChunk *> chunks = s_loader->ParseFile(inpath);
+            for (int i=0; i < chunks.size(); i++) {
+                // Emit the YAML.
+                PRS1DataChunk * chunk = chunks.at(i);
+                ChunkToYaml(file, chunk);
+                delete chunk;
+            }
+            
+            file.close();
+        }
+    }
+}
+
+void PRS1Tests::testChunksToYaml()
+{
+    iterateTestCards(TESTDATA_PATH "prs1/input/", parseAndEmitChunkYaml);
+}
+
+
 // ====================================================================================================
 
 QString prs1OutputPath(const QString & inpath, const QString & serial, int session, const QString & suffix)
+{
+    QString basename = QString("%1").arg(session, 8, 10, QChar('0'));
+    return prs1OutputPath(inpath, serial, basename, suffix);
+}
+
+QString prs1OutputPath(const QString & inpath, const QString & serial, const QString & basename, const QString & suffix)
 {
     // Output to prs1/output/FOLDER/SERIAL-000000(-session.yml, etc.)
     QDir path(inpath);
@@ -90,7 +248,7 @@ QString prs1OutputPath(const QString & inpath, const QString & serial, int sessi
     
     QString filename = QString("%1-%2%3")
                         .arg(serial)
-                        .arg(session, 6, 10, QChar('0'))
+                        .arg(basename)
                         .arg(suffix);
     return outdir.path() + QDir::separator() + filename;
 }
diff --git a/oscar/tests/prs1tests.h b/oscar/tests/prs1tests.h
index 592d7225..5c8f2992 100644
--- a/oscar/tests/prs1tests.h
+++ b/oscar/tests/prs1tests.h
@@ -18,6 +18,7 @@ class PRS1Tests : public QObject
  
 private slots:
     void initTestCase();
+    void testChunksToYaml();
     void testSessionsToYaml();
     // void test2();
     void cleanupTestCase();