Interval qdebug. Fix nextClipTime initializer. Seek on initial play i…

…f needed.

src/mediafx/clip.cpp

@@ -89,7 +89,7 @@ void Clip::initializeNextClipTime()
 {
     setNextClipTime(Interval(
         clipStartMicros(),
-        MediaFX::singletonInstance()->session()->frameDuration()));
+        clipStartMicros() + MediaFX::singletonInstance()->session()->frameDuration()));
 }
 
 void Clip::stop()

src/mediafx/interval.h

@@ -17,6 +17,8 @@
 
 #pragma once
 
+#include <QDebug>
+#include <QDebugStateSaver>
 #include <QtTypes>
 #include <utility>
 
@@ -57,3 +59,10 @@ struct Interval {
     qint64 s = 0;
     qint64 e = 0;
 };
+
+QDebug inline operator<<(QDebug dbg, const Interval& interval)
+{
+    QDebugStateSaver saver(dbg);
+    dbg.nospace() << "(" << interval.start() << ", " << interval.end() << ")";
+    return dbg;
+}

src/mediafx/video_clip.cpp

@@ -63,9 +63,6 @@ void VideoClip::onVideoFrameChanged(const QVideoFrame& frame)
     if (videoSinks().isEmpty())
         return;
 
-    // XXX need to attempt to seek - should we do that when clipStart set, or when url set? we don't know which is set first
-    // XXX seek doesn't work until we are playing, so need to do it here
-
     auto frameTimeStart = nextClipTime().start();
     if (frame.endTime() < frameTimeStart) {
         return;
@@ -104,13 +101,22 @@ void VideoClip::setActive(bool bactive)
     VisualClip::setActive(bactive);
     if (isComponentComplete()) {
         if (active()) {
-            mediaPlayer.play();
+            play();
         } else {
             mediaPlayer.pause();
         }
     }
 }
 
+void VideoClip::play()
+{
+    bool initialPlay = mediaPlayer.playbackState() == QMediaPlayer::StoppedState;
+    mediaPlayer.play();
+    if (initialPlay && clipStart() > 0 && mediaPlayer.isSeekable()) {
+        mediaPlayer.setPosition(clipStart());
+    }
+}
+
 void VideoClip::stop()
 {
     VisualClip::stop();
@@ -128,5 +134,5 @@ void VideoClip::componentComplete()
     }
     VisualClip::componentComplete();
     if (active())
-        mediaPlayer.play();
+        play();
 }

src/mediafx/video_clip.h

@@ -51,6 +51,7 @@ private slots:
     void onVideoFrameChanged(const QVideoFrame& frame);
 
 private:
+    void play();
     void rateControl();
     static const int MaxFrameQueueSize = 20;
     static const int MinFrameQueueSize = 5;