Add video filtering support to VideoOutput

Add the QAbstractVideoFilter base class and integrate it with VideoOutput.

This can be used to perform arbitrary filtering or image processing
on the frames of a video stream of a VideoOutput element right before
the OpenGL texture is provided to the scenegraph by the video node.

This opens up the possibility to integrate computer vision
frameworks or accelerated image processing with Qt Quick applications
that display video streams using Qt Multimedia.

Conceptually it is somewhat similar to QVideoProbe, this
approach however allows modifying the frame, in real time
with tight integration to the scenegraph node, and targets
Qt Quick meaning setting up the filter and processing the results
of the computations happen completely in QML.

[ChangeLog] Added QAbstractVideoFilter that serves as a base class for QML
video filtering elements that integrate compute, vision, and image processing
frameworks with VideoOutput.

Change-Id: Ice1483f8c2daec5a43536978627a7bbb64549480
Reviewed-by: Yoann Lopes <yoann.lopes@theqtcompany.com>

2 files changed, 3 insertions, 2 deletions

diff --git a/src/plugins/android/videonode/qandroidsgvideonode.cpp b/src/plugins/android/videonode/qandroidsgvideonode.cpp
index 4e1b2a89b..f094c0d8d 100644
--- a/src/plugins/android/videonode/qandroidsgvideonode.cpp
+++ b/src/plugins/android/videonode/qandroidsgvideonode.cpp
@@ -165,7 +165,7 @@ QAndroidSGVideoNode::~QAndroidSGVideoNode()
     m_frame = QVideoFrame();
 }
 
-void QAndroidSGVideoNode::setCurrentFrame(const QVideoFrame &frame)
+void QAndroidSGVideoNode::setCurrentFrame(const QVideoFrame &frame, FrameFlags)
 {
     QMutexLocker lock(&m_frameMutex);
     m_frame = frame;
diff --git a/src/plugins/android/videonode/qandroidsgvideonode.h b/src/plugins/android/videonode/qandroidsgvideonode.h
index f3f838331..0c50d8cf9 100644
--- a/src/plugins/android/videonode/qandroidsgvideonode.h
+++ b/src/plugins/android/videonode/qandroidsgvideonode.h
@@ -47,8 +47,9 @@ public:
     QAndroidSGVideoNode(const QVideoSurfaceFormat &format);
     ~QAndroidSGVideoNode();
 
-    void setCurrentFrame(const QVideoFrame &frame);
+    void setCurrentFrame(const QVideoFrame &frame, FrameFlags flags);
     QVideoFrame::PixelFormat pixelFormat() const { return m_format.pixelFormat(); }
+    QAbstractVideoBuffer::HandleType handleType() const { return QAbstractVideoBuffer::GLTextureHandle; }
 
     void preprocess();