reimplement sample import using ffmpeg

notes

@@ -32,8 +32,9 @@ parameters {
 
 TODO {
     immediate frontburner {
-        reimplement sample import to IPC from standalone ffmpeg since QAudioDecoder is partially broken on arch and completely broken on macOS
-        ffprobe -v quiet -show_streams -select_streams a -of json testOut.mp3
+        - reimplement sample import to IPC from standalone ffmpeg since QAudioDecoder is partially broken on arch and completely broken on macOS
+        # ffprobe -v quiet -show_streams -select_streams a -of json testOut.mp3
+        # ffmpeg -i input.flv -f f32le -acodec pcm_f32le -
         
         distortion effect
         single-selection sampler

xybrid/data/sample.cpp

@@ -9,11 +9,18 @@ using namespace Xybrid::Data;
 #include <QCborMap>
 #include <QCborArray>
 
+#include <QJsonDocument>
+#include <QJsonArray>
+#include <QJsonObject>
+
 #include <QFileInfo>
 
 #include <QAudioDecoder>
 #include <QAudioFormat>
 
+#include <QProcess>
+#include <QDataStream>
+
 #include <QEventLoop>
 
 #define qs QStringLiteral
@@ -88,6 +95,7 @@ bool Sample::changeUuid(QUuid newUuid) {
 
 void Sample::newUuid() { changeUuid(QUuid::createUuid()); }
 
+#ifdef OLD_SAMPLE_IMPORT
 namespace {
     bool blah [[maybe_unused]];
     template<typename T> void insertbuf(std::shared_ptr<Sample> smp, const T* data, size_t len, size_t channels) {
@@ -154,6 +162,63 @@ std::shared_ptr<Sample> Sample::fromFile(QString fileName) {
 
     return smp;
 }
+#else
+std::shared_ptr<Sample> Sample::fromFile(QString fileName) {
+    QJsonObject info;
+    {
+        // get stream info
+        QProcess probe;
+        QStringList param;
+        param << "-v" << "quiet" << "-show_streams" << "-select_streams" << "a" << "-of" << "json";
+        param << fileName;
+        probe.start("ffprobe", param);
+        probe.waitForFinished();
+
+        auto doc = QJsonDocument::fromJson(probe.readAllStandardOutput());
+        info = doc.object()["streams"].toArray().first().toObject();
+    }
+    if (!info.contains("sample_rate") || !info.contains("channels")) return nullptr; // no/invalid audio streams
+
+    int channels = info["channels"].toInt();
+    int sampleRate = info["sample_rate"].toString().toInt(); // for some reason ffprobe stores this as a string??
+
+    auto smp = std::make_shared<Sample>();
+    smp->sampleRate = sampleRate;
+
+    // grab raw pcm_f32le via ffmpeg
+    QByteArray raw;
+    {
+        QProcess dec;
+        QStringList param;
+        param << "-i" << fileName << "-f" << "f32le" << "-acodec" << "pcm_f32le" << "-";
+        dec.start("ffmpeg", param);
+        dec.waitForFinished();
+        raw = dec.readAllStandardOutput();
+    }
+    // pre-size sample data buffers
+    auto len = static_cast<size_t>((raw.length() / channels) / 4);
+    smp->data[0].reserve(len);
+    if (channels > 1) smp->data[1].reserve(len);
+
+    // read raw bytes into channels
+    QDataStream r(&raw, QIODevice::ReadOnly);
+    size_t chs = static_cast<size_t>(channels);
+    size_t ch = chs;
+    float f;
+    while (!r.atEnd()) {
+        r.readRawData(reinterpret_cast<char*>(&f), sizeof(f));
+        ch = (ch+1) % chs;
+        if (ch < 2) smp->data[ch].push_back(f);
+    }
+
+    // add info
+    smp->uuid = QUuid::createUuid();
+    smp->name = QFileInfo(fileName).baseName();
+
+    return smp;
+}
+
+#endif
 
 namespace {
     bool exporting = false;