video stepBackward()/Forward(). deprecate playNextFrame()

currently only step backward to the previous displayed frame

examples/player/EventFilter.cpp

@@ -135,7 +135,10 @@ bool EventFilter::eventFilter(QObject *watched, QEvent *event)
             player->videoCapture()->capture();
             break;
         case Qt::Key_N: //check playing?
-            player->playNextFrame();
+            player->stepForward();
+            break;
+        case Qt::Key_B:
+            player->stepBackward();
             break;
         case Qt::Key_P:
             player->play();

examples/videowall/VideoWall.cpp

@@ -256,7 +256,7 @@ bool VideoWall::eventFilter(QObject *watched, QEvent *event)
             break;
         case Qt::Key_N: //check playing?
             foreach (AVPlayer* player, players) {
-                player->playNextFrame();
+                player->stepForward();
             }
             break;
 

qml/QmlAVPlayer.cpp

@@ -608,7 +608,7 @@ void QmlAVPlayer::nextFrame()
 {
     if (!mpPlayer)
         return;
-    mpPlayer->playNextFrame();
+    mpPlayer->stepForward();
 }
 
 void QmlAVPlayer::seek(int offset)

src/AVDemuxThread.cpp

@@ -137,6 +137,67 @@ AVThread* AVDemuxThread::audioThread()
     return audio_thread;
 }
 
+void AVDemuxThread::stepBackward()
+{
+    if (!video_thread)
+        return;
+    AVThread *t = video_thread;
+    const qreal pre_pts = video_thread->previousHistoryPts();
+    if (pre_pts == 0.0) {
+        qWarning("can not get previous pts");
+        return;
+    }
+    end = false;
+    // queue maybe blocked by put()
+    if (audio_thread) {
+        audio_thread->packetQueue()->clear(); // will put new packets before task run
+    }
+
+    class stepBackwardTask : public QRunnable {
+    public:
+        stepBackwardTask(AVDemuxThread *dt, qreal t)
+            : demux_thread(dt)
+            , pts(t)
+        {}
+        void run() {
+            AVThread *avt = demux_thread->videoThread();
+            avt->packetQueue()->clear(); // clear here
+            if (pts <= 0) {
+                demux_thread->demuxer->seek(qint64(-pts*1000.0) - 1000LL);
+                QVector<qreal> ts;
+                qreal t = -1.0;
+                while (t < -pts) {
+                    demux_thread->demuxer->readFrame();
+                    if (demux_thread->demuxer->stream() != demux_thread->demuxer->videoStream())
+                        continue;
+                    t = demux_thread->demuxer->packet().pts;
+                    ts.push_back(t);
+                }
+                ts.pop_back();
+                pts = ts.back();
+            }
+            qDebug("step backward: %lld, %f", qint64(pts*1000.0), pts);
+            demux_thread->seekInternal(qint64(pts*1000.0), AccurateSeek);
+        }
+    private:
+        AVDemuxThread *demux_thread;
+        qreal pts;
+    };
+
+    pause(true);
+    // set clock first
+    if (clock_type < 0)
+        clock_type = (int)video_thread->clock()->isClockAuto() + 2*(int)video_thread->clock()->clockType();
+    video_thread->clock()->setClockType(AVClock::VideoClock);
+    t->packetQueue()->clear(); // will put new packets before task run
+    t->packetQueue();
+    Packet pkt;
+    pkt.pts = qreal(pre_pts)/1000.0;
+    t->packetQueue()->put(pkt); // clear and put a seek packet to ensure not frames other than previous frame will be decoded and rendered
+    video_thread->pause(false);
+    newSeekRequest(new stepBackwardTask(this, pre_pts));
+}
+
 void AVDemuxThread::seek(qint64 pos, SeekType type)
 {
     end = false;
@@ -346,6 +407,11 @@ void AVDemuxThread::seekOnPauseFinished()
         if (audio_thread)
             audio_thread->pause(true);
     }
+    if (clock_type >= 0) {
+        thread->clock()->setClockAuto(clock_type & 1);
+        thread->clock()->setClockType(AVClock::ClockType(clock_type/2));
+        clock_type = -1;
+    }
 }
 
 void AVDemuxThread::frameDeliveredNextFrame()

src/AVDemuxThread.h

@@ -45,6 +45,7 @@ class AVDemuxThread : public QThread
     AVThread* audioThread();
     void setVideoThread(AVThread *thread);
     AVThread* videoThread();
+    void stepBackward();
     void seek(qint64 pos, SeekType type); //ms
     //AVDemuxer* demuxer
     bool isPaused() const;
@@ -99,6 +100,7 @@ private slots:
     QMutex next_frame_mutex;
     int clock_type; // change happens in different threads(direct connection)
     friend class SeekTask;
+    friend class stepBackwardTask;
 };
 
 } //namespace QtAV

src/AVPlayer.cpp

@@ -128,7 +128,6 @@ void AVPlayer::clearVideoRenderers()
     d->vos->clearOutputs();
 }
 
-//TODO: check components compatiblity(also when change the filter chain)
 void AVPlayer::setRenderer(VideoRenderer *r)
 {
     VideoRenderer *vo = renderer();
@@ -539,7 +538,6 @@ bool AVPlayer::play(const QString& path)
     return true;//isPlaying();
 }
 
-// TODO: check repeat status?
 bool AVPlayer::isPlaying() const
 {
     return (d->read_thread &&d->read_thread->isRunning())
@@ -868,7 +866,7 @@ qreal AVPlayer::positionF() const
 
 qint64 AVPlayer::position() const
 {
-    const qint64 pts = d->clock->value()*1000.0; //TODO: avoid *1000.0
+    const qint64 pts = d->clock->value()*1000.0;
     if (relativeTimeMode())
         return pts - absoluteMediaStartPosition();
     return pts;
@@ -1079,7 +1077,6 @@ bool AVPlayer::setSubtitleStream(int n)
 {
     if (d->subtitle_track == n)
         return true;
-    // TODO: xxxchanged signal
     d->subtitle_track = n;
     Q_EMIT subtitleStreamChanged(n);
     if (!d->demuxer.isLoaded())
@@ -1457,14 +1454,24 @@ void AVPlayer::timerEvent(QTimerEvent *te)
     }
 }
 
-//FIXME: If not playing, it will just play but not play one frame.
 void AVPlayer::playNextFrame()
+{
+    stepForward();
+}
+
+//FIXME: If not playing, it will just play but not play one frame.
+void AVPlayer::stepForward()
 {
     // pause clock
     pause(true); // must pause AVDemuxThread (set user_paused true)
     d->read_thread->nextFrame();
 }
 
+void AVPlayer::stepBackward()
+{
+    d->read_thread->stepBackward();
+}
+
 void AVPlayer::seek(qreal r)
 {
     seek(qint64(r*double(duration())));

src/AVThread.cpp

@@ -141,6 +141,18 @@ void AVThread::scheduleFrameDrop(bool value)
     scheduleTask(new FrameDropTask(decoder(), value));
 }
 
+qreal AVThread::previousHistoryPts() const
+{
+    DPTR_D(const AVThread);
+    if (d.pts_history.empty()) {
+        qDebug("pts history is EMPTY");
+        return 0;
+    }
+    if (d.pts_history.size() == 1)
+        return -d.pts_history.back();
+    return d.pts_history.at(d.pts_history.size() - 2);
+}
+
 // TODO: shall we close decoder here?
 void AVThread::stop()
 {

src/AVThread.h

@@ -76,6 +76,7 @@ class AVThread : public QThread
     // TODO: resample, resize task etc.
     void scheduleTask(QRunnable *task);
     void scheduleFrameDrop(bool value = true);
+    qreal previousHistoryPts() const;
 
 public slots:
     virtual void stop();

src/AVThread_p.h

@@ -27,6 +27,7 @@
 #include <QtCore/QVariant>
 #include <QtCore/QWaitCondition>
 #include "PacketBuffer.h"
+#include "utils/ring.h"
 
 class QRunnable;
 namespace QtAV {
@@ -53,6 +54,7 @@ class AVThreadPrivate : public DPtrPrivate<AVThread>
       , statistics(0)
       , ready(false)
       , render_pts0(-1)
+      , pts_history(30, -1)
     {
         tasks.blockFull(false);
 
@@ -83,6 +85,7 @@ class AVThreadPrivate : public DPtrPrivate<AVThread>
     qreal render_pts0;
 
     static QVariantHash dec_opt_framedrop, dec_opt_normal;
+    ring<qreal> pts_history;
 };
 
 } //namespace QtAV

src/QtAV/AVPlayer.h

@@ -363,9 +363,17 @@ public slots:
      */
     void play(); //replay
     void stop();
-    void playNextFrame(); //deprecated
-    //void stepForward();
-    //void stepBackward();
+    QTAV_DEPRECATED void playNextFrame(); //deprecated. use stepForward instead
+    /*!
+     * \brief stepForward
+     * Play the next frame and pause
+     */
+    void stepForward();
+    /*!
+     * \brief stepBackward
+     * Play the previous frame and pause. Currently only support the previous decoded frames
+     */
+    void stepBackward();
 
     void setRelativeTimeMode(bool value);
     /*!

src/VideoThread.cpp

@@ -286,9 +286,9 @@ void VideoThread::run()
     const char* pkt_data = NULL; // workaround for libav9 decode fail but error code >= 0
     while (true) {
         processNextTask();
-        //TODO: why put it at the end of loop then playNextFrame() not work?
+        //TODO: why put it at the end of loop then stepForward() not work?
         //processNextTask tryPause(timeout) and  and continue outter loop
-        if (tryPause()) { //DO NOT continue, or playNextFrame() will fail
+        if (tryPause()) { //DO NOT continue, or stepForward() will fail
 
         } else {
             if (isPaused())
@@ -312,6 +312,7 @@ void VideoThread::run()
                 qDebug("Invalid packet! flush video codec context!!!!!!!!!! video packet queue size: %d", d.packets.size());  
                 d.dec->flush(); //d.dec instead of dec because d.dec maybe changed in processNextTask() but dec is not
                 d.render_pts0 = pkt.pts;
+                d.pts_history = ring<qreal>(d.pts_history.capacity(), -1);
                 continue;
             }
         }
@@ -487,13 +488,16 @@ void VideoThread::run()
         const qreal pts = frame.timestamp();
         // seek finished because we can ensure no packet before seek decoded when render_pts0 is set
         //qDebug("pts0: %f, pts: %f", d.render_pts0, pts);
+        d.pts_history.push_back(pts);
+
         if (d.render_pts0 >= 0.0) {
             if (pts < d.render_pts0) {
                 if (!pkt.isEOF())
                     pkt = Packet();
                 continue;
             }
             d.render_pts0 = -1;
+            qDebug("seek finished @%f", pts);
             Q_EMIT seekFinished(qint64(pts*1000.0));
             if (seek_count == -1)
                 seek_count = 1;