feat: add subtitle track selection, secondary subtitle and delay

src/mpv/mpvitem.cpp

@@ -2,19 +2,38 @@
 
 #include <MpvController>
 
+#include <cmath>
 #include <utility>
 
+namespace
+{
+QString localPathOrUrl(const QUrl &url)
+{
+    return url.isLocalFile() ? url.toLocalFile() : url.toString();
+}
+
+// mpv takes "no" to deselect a track.
+QVariant trackIdValue(int id)
+{
+    return id > 0 ? QVariant(id) : QVariant(QStringLiteral("no"));
+}
+}
+
 MpvItem::MpvItem(QQuickItem *parent)
     : MpvAbstractItem(parent)
 {
     // Leave the player on the last frame at end of file instead of unloading it.
     setPropertyAsync(QStringLiteral("keep-open"), QStringLiteral("yes"));
     setPropertyAsync(QStringLiteral("hwdec"), QStringLiteral("auto-safe"));
+    // Also pick up "movie.en.srt" style files next to "movie.mkv".
+    setPropertyAsync(QStringLiteral("sub-auto"), QStringLiteral("fuzzy"));
 
     observeProperty(QStringLiteral("media-title"), MPV_FORMAT_STRING);
     observeProperty(QStringLiteral("time-pos"), MPV_FORMAT_DOUBLE);
     observeProperty(QStringLiteral("duration"), MPV_FORMAT_DOUBLE);
     observeProperty(QStringLiteral("pause"), MPV_FORMAT_FLAG);
+    observeProperty(QStringLiteral("track-list"), MPV_FORMAT_NODE);
+    observeProperty(QStringLiteral("sub-delay"), MPV_FORMAT_DOUBLE);
 
     // MpvController lives on a worker thread; queue its signals back to the GUI thread.
     connect(mpvController(), &MpvController::propertyChanged, this, &MpvItem::onPropertyChanged, Qt::QueuedConnection);
@@ -98,9 +117,10 @@ void MpvItem::loadFile(const QUrl &url)
         return;
     }
 
-    const QString target = url.isLocalFile() ? url.toLocalFile() : url.toString();
-    commandAsync(QStringList{QStringLiteral("loadfile"), target});
+    commandAsync(QStringList{QStringLiteral("loadfile"), localPathOrUrl(url)});
     setPropertyAsync(QStringLiteral("pause"), false);
+    // sub-delay is global in mpv; start every file in sync.
+    setSubtitleDelay(0.0);
 }
 
 void MpvItem::togglePause()
@@ -113,6 +133,63 @@ void MpvItem::seek(double seconds)
     commandAsync(QStringList{QStringLiteral("seek"), QString::number(seconds), QStringLiteral("absolute")});
 }
 
+QVariantList MpvItem::subtitleTracks() const
+{
+    return m_subtitleTracks;
+}
+
+int MpvItem::subtitleId() const
+{
+    return m_subtitleId;
+}
+
+void MpvItem::setSubtitleId(int id)
+{
+    setPropertyAsync(QStringLiteral("sid"), trackIdValue(id));
+}
+
+int MpvItem::secondarySubtitleId() const
+{
+    return m_secondarySubtitleId;
+}
+
+void MpvItem::setSecondarySubtitleId(int id)
+{
+    setPropertyAsync(QStringLiteral("secondary-sid"), trackIdValue(id));
+}
+
+double MpvItem::subtitleDelay() const
+{
+    return m_subtitleDelay;
+}
+
+void MpvItem::setSubtitleDelay(double seconds)
+{
+    // Keep whole milliseconds so repeated +/-0.1 steps don't drift.
+    const double rounded = std::round(seconds * 1000.0) / 1000.0;
+    // Update right away so quick repeated steps build on each other instead of on the
+    // last value mpv reported; mpv confirms it through the observed property.
+    if (rounded != m_subtitleDelay) {
+        m_subtitleDelay = rounded;
+        Q_EMIT subtitleDelayChanged();
+    }
+    setPropertyAsync(QStringLiteral("sub-delay"), rounded);
+    setPropertyAsync(QStringLiteral("secondary-sub-delay"), rounded);
+}
+
+void MpvItem::addSubtitleFile(const QUrl &url)
+{
+    if (!url.isValid()) {
+        return;
+    }
+    commandAsync(QStringList{QStringLiteral("sub-add"), localPathOrUrl(url), QStringLiteral("select")});
+}
+
+void MpvItem::showText(const QString &text)
+{
+    commandAsync(QStringList{QStringLiteral("show-text"), text});
+}
+
 void MpvItem::onPropertyChanged(const QString &property, const QVariant &value)
 {
     if (property == u"media-title") {
@@ -127,9 +204,52 @@ void MpvItem::onPropertyChanged(const QString &property, const QVariant &value)
     } else if (property == u"pause") {
         m_paused = value.toBool();
         Q_EMIT pausedChanged();
+    } else if (property == u"track-list") {
+        updateTracks(value.toList());
+    } else if (property == u"sub-delay") {
+        m_subtitleDelay = value.toDouble();
+        Q_EMIT subtitleDelayChanged();
     }
 }
 
+void MpvItem::updateTracks(const QVariantList &trackList)
+{
+    QVariantList subtitles;
+    int primary = 0;
+    int secondary = 0;
+
+    for (const QVariant &entry : trackList) {
+        const QVariantMap track = entry.toMap();
+        if (track.value(QStringLiteral("type")).toString() != u"sub") {
+            continue;
+        }
+
+        const int id = track.value(QStringLiteral("id")).toInt();
+        if (track.value(QStringLiteral("selected")).toBool()) {
+            // main-selection is 0 for the primary subtitle and 1 for the secondary one.
+            if (track.value(QStringLiteral("main-selection")).toInt() == 0) {
+                primary = id;
+            } else {
+                secondary = id;
+            }
+        }
+
+        subtitles.append(QVariantMap{
+            {QStringLiteral("id"), id},
+            {QStringLiteral("title"), track.value(QStringLiteral("title")).toString()},
+            {QStringLiteral("lang"), track.value(QStringLiteral("lang")).toString()},
+            {QStringLiteral("codec"), track.value(QStringLiteral("codec")).toString()},
+            {QStringLiteral("external"), track.value(QStringLiteral("external")).toBool()},
+            {QStringLiteral("externalFilename"), track.value(QStringLiteral("external-filename")).toString()},
+        });
+    }
+
+    m_subtitleTracks = subtitles;
+    m_subtitleId = primary;
+    m_secondarySubtitleId = secondary;
+    Q_EMIT subtitleTracksChanged();
+}
+
 void MpvItem::setFileLoaded(bool loaded)
 {
     if (loaded == m_fileLoaded) {