tmp example

examples/streamer/streamer.cpp

@@ -51,6 +51,25 @@
 #include "streamer.h"
 #include <QQuickItemGrabResult>
 
+void AppSrc::imageReady()
+{
+    m_frame = m_grabResult->image();
+    m_grabResult.reset();
+}
+
+QVideoFrame AppSrc::readFrame() const
+{
+    if (!m_frame.isValid() && m_streamer->item()) {
+        m_grabResult = qobject_cast<QQuickItem*>(m_streamer->item())->grabToImage();
+        connect(m_grabResult.data(), &QQuickItemGrabResult::ready, this, &AppSrc::imageReady);
+    }
+
+    auto frame = m_frame;
+    m_frame = QVideoFrame();
+
+    return frame;
+}
+
 Streamer::Streamer(QObject *parent)
     : QGstreamerPipeline(parent)
 {
@@ -65,10 +84,11 @@ QObject *Streamer::item() const
 
 void Streamer::setItem(QObject *src)
 {
-    if (src == m_item)
+    auto item = qobject_cast<QQuickItem*>(src);
+    if (m_item == item)
         return;
 
-    m_item = qobject_cast<QQuickItem*>(src);
+    m_item = item;
     emit itemChanged();
 }
 
@@ -85,17 +105,3 @@ void Streamer::onPipelineChanged()
     m_appsrc.reset(new AppSrc(this, appsrc));
 }
 
-QVideoFrame AppSrc::readFrame() const
-{
-    if (!m_frame.isValid() && m_streamer->item()) {
-        auto result = qobject_cast<QQuickItem*>(m_streamer->item())->grabToImage();
-        connect(result.data(), &QQuickItemGrabResult::ready, result.data(), [this, result](){
-            m_frame = result->image();
-        });
-    }
-
-    auto frame = m_frame;
-    m_frame = QVideoFrame();
-
-    return frame;
-}

examples/streamer/streamer.h

@@ -72,8 +72,12 @@ public:
 protected:
     QVideoFrame readFrame() const override;
 
+private Q_SLOTS:
+    void imageReady();
+
 private:
     Streamer *m_streamer = nullptr;
+    mutable QSharedPointer<QQuickItemGrabResult> m_grabResult;
     mutable QVideoFrame m_frame;
 };