Merge remote-tracking branch 'origin/5.6' into 5.7

Change-Id: Ic29cb09048003f18ff86d4546cd547be715eaec8

16 files changed, 181 insertions, 111 deletions

diff --git a/src/plugins/android/jar/src/org/qtproject/qt5/android/multimedia/QtSurfaceTextureListener.java b/src/plugins/android/jar/src/org/qtproject/qt5/android/multimedia/QtSurfaceTextureListener.java
index 0404e2d75..a997dde90 100644
--- a/src/plugins/android/jar/src/org/qtproject/qt5/android/multimedia/QtSurfaceTextureListener.java
+++ b/src/plugins/android/jar/src/org/qtproject/qt5/android/multimedia/QtSurfaceTextureListener.java
@@ -43,18 +43,18 @@ import android.graphics.SurfaceTexture;
 
 public class QtSurfaceTextureListener implements SurfaceTexture.OnFrameAvailableListener
 {
-    private final int texID;
+    private final long m_id;
 
-    public QtSurfaceTextureListener(int texName)
+    public QtSurfaceTextureListener(long id)
     {
-        texID = texName;
+        m_id = id;
     }
 
     @Override
     public void onFrameAvailable(SurfaceTexture surfaceTexture)
     {
-        notifyFrameAvailable(texID);
+        notifyFrameAvailable(m_id);
     }
 
-    private static native void notifyFrameAvailable(int id);
+    private static native void notifyFrameAvailable(long id);
 }
diff --git a/src/plugins/android/src/common/qandroidvideooutput.cpp b/src/plugins/android/src/common/qandroidvideooutput.cpp
index 5c804ccc4..a5cd3580b 100644
--- a/src/plugins/android/src/common/qandroidvideooutput.cpp
+++ b/src/plugins/android/src/common/qandroidvideooutput.cpp
@@ -147,7 +147,13 @@ public:
         delete m_program;
     }
 
-    void setTexture(quint32 id) { m_textureID = id; }
+    void setTexture(quint32 id) {
+        if (m_textureID)
+            glDeleteTextures(1, &m_textureID);
+
+        m_textureID = id;
+    }
+
     void setFbo(QOpenGLFramebufferObject *fbo) { m_fbo = fbo; }
     void setShaderProgram(QOpenGLShaderProgram *prog) { m_program = prog; }
 
diff --git a/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp b/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
index 9137fbc05..0b082b02b 100644
--- a/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
+++ b/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
@@ -295,16 +295,27 @@ void QAndroidCameraSession::applyViewfinderSettings(const QSize &captureSize, bo
             adjustedViewfinderResolution = vfRes;
         } else if (validCaptureSize) {
             // search for viewfinder resolution with the same aspect ratio
+            qreal minAspectDiff = 1;
+            QSize closestResolution;
             for (int i = previewSizes.count() - 1; i >= 0; --i) {
                 const QSize &size = previewSizes.at(i);
-                if (qAbs(captureAspectRatio - (qreal(size.width()) / size.height())) < 0.01) {
+                const qreal sizeAspect = qreal(size.width()) / size.height();
+                if (qFuzzyCompare(captureAspectRatio, sizeAspect)) {
                     adjustedViewfinderResolution = size;
                     break;
+                } else if (minAspectDiff > qAbs(sizeAspect - captureAspectRatio)) {
+                    closestResolution = size;
+                    minAspectDiff = qAbs(sizeAspect - captureAspectRatio);
                 }
             }
             if (!adjustedViewfinderResolution.isValid()) {
                 qWarning("Cannot find a viewfinder resolution matching the capture aspect ratio.");
-                return;
+                if (closestResolution.isValid()) {
+                    adjustedViewfinderResolution = closestResolution;
+                    qWarning("Using closest viewfinder resolution.");
+                } else {
+                    return;
+                }
             }
         } else {
             adjustedViewfinderResolution = previewSizes.last();
diff --git a/src/plugins/android/src/qandroidmediaserviceplugin.cpp b/src/plugins/android/src/qandroidmediaserviceplugin.cpp
index 87de7d561..0de231c9d 100644
--- a/src/plugins/android/src/qandroidmediaserviceplugin.cpp
+++ b/src/plugins/android/src/qandroidmediaserviceplugin.cpp
@@ -150,6 +150,11 @@ QT_END_NAMESPACE
 
 Q_DECL_EXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void * /*reserved*/)
 {
+    static bool initialized = false;
+    if (initialized)
+        return JNI_VERSION_1_6;
+    initialized = true;
+
     QT_USE_NAMESPACE
     typedef union {
         JNIEnv *nativeEnvironment;
diff --git a/src/plugins/android/src/wrappers/jni/androidsurfacetexture.cpp b/src/plugins/android/src/wrappers/jni/androidsurfacetexture.cpp
index 82a8bffe3..df09d0819 100644
--- a/src/plugins/android/src/wrappers/jni/androidsurfacetexture.cpp
+++ b/src/plugins/android/src/wrappers/jni/androidsurfacetexture.cpp
@@ -40,24 +40,32 @@
 #include "androidsurfacetexture.h"
 #include <QtCore/private/qjni_p.h>
 #include <QtCore/private/qjnihelpers_p.h>
+#include <QtCore/qmutex.h>
 
 QT_BEGIN_NAMESPACE
 
 static const char QtSurfaceTextureListenerClassName[] = "org/qtproject/qt5/android/multimedia/QtSurfaceTextureListener";
-static QMap<int, AndroidSurfaceTexture*> g_objectMap;
+typedef QVector<jlong> SurfaceTextures;
+Q_GLOBAL_STATIC(SurfaceTextures, g_surfaceTextures);
+Q_GLOBAL_STATIC(QMutex, g_textureMutex);
 
 // native method for QtSurfaceTexture.java
-static void notifyFrameAvailable(JNIEnv* , jobject, int id)
+static void notifyFrameAvailable(JNIEnv* , jobject, jlong id)
 {
-    AndroidSurfaceTexture *obj = g_objectMap.value(id, 0);
+    const QMutexLocker lock(g_textureMutex);
+    const int idx = g_surfaceTextures->indexOf(id);
+    if (idx == -1)
+        return;
+
+    AndroidSurfaceTexture *obj = reinterpret_cast<AndroidSurfaceTexture *>(g_surfaceTextures->at(idx));
     if (obj)
         Q_EMIT obj->frameAvailable();
 }
 
 AndroidSurfaceTexture::AndroidSurfaceTexture(unsigned int texName)
     : QObject()
-    , m_texID(int(texName))
 {
+    Q_STATIC_ASSERT(sizeof (jlong) >= sizeof (void *));
     // API level 11 or higher is required
     if (QtAndroidPrivate::androidSdkVersion() < 11) {
         qWarning("Camera preview and video playback require Android 3.0 (API level 11) or later.");
@@ -73,13 +81,13 @@ AndroidSurfaceTexture::AndroidSurfaceTexture(unsigned int texName)
         env->ExceptionClear();
     }
 
-    if (m_surfaceTexture.isValid())
-        g_objectMap.insert(int(texName), this);
+    if (!m_surfaceTexture.isValid())
+        return;
 
-    QJNIObjectPrivate listener(QtSurfaceTextureListenerClassName, "(I)V", jint(texName));
-    m_surfaceTexture.callMethod<void>("setOnFrameAvailableListener",
-                                      "(Landroid/graphics/SurfaceTexture$OnFrameAvailableListener;)V",
-                                      listener.object());
+    const QMutexLocker lock(g_textureMutex);
+    g_surfaceTextures->append(jlong(this));
+    QJNIObjectPrivate listener(QtSurfaceTextureListenerClassName, "(J)V", jlong(this));
+    setOnFrameAvailableListener(listener);
 }
 
 AndroidSurfaceTexture::~AndroidSurfaceTexture()
@@ -89,7 +97,10 @@ AndroidSurfaceTexture::~AndroidSurfaceTexture()
 
     if (m_surfaceTexture.isValid()) {
         release();
-        g_objectMap.remove(m_texID);
+        const QMutexLocker lock(g_textureMutex);
+        const int idx = g_surfaceTextures->indexOf(jlong(this));
+        if (idx != -1)
+            g_surfaceTextures->remove(idx);
     }
 }
 
@@ -178,7 +189,7 @@ bool AndroidSurfaceTexture::initJNI(JNIEnv *env)
                                                      env);
 
     static const JNINativeMethod methods[] = {
-        {"notifyFrameAvailable", "(I)V", (void *)notifyFrameAvailable}
+        {"notifyFrameAvailable", "(J)V", (void *)notifyFrameAvailable}
     };
 
     if (clazz && env->RegisterNatives(clazz,
@@ -190,4 +201,11 @@ bool AndroidSurfaceTexture::initJNI(JNIEnv *env)
     return true;
 }
 
+void AndroidSurfaceTexture::setOnFrameAvailableListener(const QJNIObjectPrivate &listener)
+{
+    m_surfaceTexture.callMethod<void>("setOnFrameAvailableListener",
+                                      "(Landroid/graphics/SurfaceTexture$OnFrameAvailableListener;)V",
+                                      listener.object());
+}
+
 QT_END_NAMESPACE
diff --git a/src/plugins/android/src/wrappers/jni/androidsurfacetexture.h b/src/plugins/android/src/wrappers/jni/androidsurfacetexture.h
index b45ee384c..0a271287a 100644
--- a/src/plugins/android/src/wrappers/jni/androidsurfacetexture.h
+++ b/src/plugins/android/src/wrappers/jni/androidsurfacetexture.h
@@ -54,7 +54,6 @@ public:
     explicit AndroidSurfaceTexture(unsigned int texName);
     ~AndroidSurfaceTexture();
 
-    int textureID() const { return m_texID; }
     jobject surfaceTexture();
     jobject surface();
     jobject surfaceHolder();
@@ -73,7 +72,8 @@ Q_SIGNALS:
     void frameAvailable();
 
 private:
-    int m_texID;
+    void setOnFrameAvailableListener(const QJNIObjectPrivate &listener);
+
     QJNIObjectPrivate m_surfaceTexture;
     QJNIObjectPrivate m_surface;
     QJNIObjectPrivate m_surfaceHolder;
diff --git a/src/plugins/avfoundation/camera/avfmediaassetwriter.h b/src/plugins/avfoundation/camera/avfmediaassetwriter.h
index fa1ec46a2..624906c85 100644
--- a/src/plugins/avfoundation/camera/avfmediaassetwriter.h
+++ b/src/plugins/avfoundation/camera/avfmediaassetwriter.h
@@ -44,7 +44,6 @@
 
 #include <QtCore/qglobal.h>
 #include <QtCore/qatomic.h>
-#include <QtCore/qmutex.h>
 
 #include <AVFoundation/AVFoundation.h>
 
@@ -53,13 +52,10 @@ QT_BEGIN_NAMESPACE
 class AVFMediaRecorderControlIOS;
 class AVFCameraService;
 
-typedef QAtomicInteger<bool> AVFAtomicBool;
 typedef QAtomicInteger<qint64> AVFAtomicInt64;
 
 QT_END_NAMESPACE
 
-// TODO: any reasonable error handling requires smart pointers, otherwise it's getting crappy immediately.
-
 @interface QT_MANGLE_NAMESPACE(AVFMediaAssetWriter) : NSObject<AVCaptureVideoDataOutputSampleBufferDelegate,
                                                                AVCaptureAudioDataOutputSampleBufferDelegate>
 {
@@ -72,22 +68,20 @@ QT_END_NAMESPACE
     QT_PREPEND_NAMESPACE(AVFScopedPointer)<AVAssetWriterInput> m_audioWriterInput;
     AVCaptureDevice *m_audioCaptureDevice;
 
+    // Queue to write sample buffers:
+    QT_PREPEND_NAMESPACE(AVFScopedPointer)<dispatch_queue_t> m_writerQueue;
     // High priority serial queue for video output:
     QT_PREPEND_NAMESPACE(AVFScopedPointer)<dispatch_queue_t> m_videoQueue;
     // Serial queue for audio output:
     QT_PREPEND_NAMESPACE(AVFScopedPointer)<dispatch_queue_t> m_audioQueue;
-    // Queue to write sample buffers:
-    QT_PREPEND_NAMESPACE(AVFScopedPointer)<dispatch_queue_t> m_writerQueue;
 
     QT_PREPEND_NAMESPACE(AVFScopedPointer)<AVAssetWriter> m_assetWriter;
 
     QT_PREPEND_NAMESPACE(AVFMediaRecorderControlIOS) *m_delegate;
 
     bool m_setStartTime;
-    QT_PREPEND_NAMESPACE(AVFAtomicBool) m_stopped;
-    QT_PREPEND_NAMESPACE(AVFAtomicBool) m_aborted;
 
-    QT_PREPEND_NAMESPACE(QMutex) m_writerMutex;
+    QT_PREPEND_NAMESPACE(QAtomicInt) m_state;
 @public
     QT_PREPEND_NAMESPACE(AVFAtomicInt64) m_durationInMs;
 @private
@@ -98,8 +92,7 @@ QT_END_NAMESPACE
     NSDictionary *m_videoSettings;
 }
 
-- (id)initWithQueue:(dispatch_queue_t)writerQueue
-      delegate:(QT_PREPEND_NAMESPACE(AVFMediaRecorderControlIOS) *)delegate;
+- (id)initWithDelegate:(QT_PREPEND_NAMESPACE(AVFMediaRecorderControlIOS) *)delegate;
 
 - (bool)setupWithFileURL:(NSURL *)fileURL
         cameraService:(QT_PREPEND_NAMESPACE(AVFCameraService) *)service
@@ -107,10 +100,10 @@ QT_END_NAMESPACE
         videoSettings:(NSDictionary *)videoSettings
         transform:(CGAffineTransform)transform;
 
+// This to be called from the recorder control's thread:
 - (void)start;
 - (void)stop;
-// This to be called if control's dtor gets called,
-// on the control's thread.
+// This to be called from the recorder control's dtor:
 - (void)abort;
 
 @end
diff --git a/src/plugins/avfoundation/camera/avfmediaassetwriter.mm b/src/plugins/avfoundation/camera/avfmediaassetwriter.mm
index 98c8f99ff..28735bc6a 100644
--- a/src/plugins/avfoundation/camera/avfmediaassetwriter.mm
+++ b/src/plugins/avfoundation/camera/avfmediaassetwriter.mm
@@ -46,7 +46,6 @@
 #include "avfcameradebug.h"
 #include "avfmediacontainercontrol.h"
 
-//#include <QtCore/qmutexlocker.h>
 #include <QtCore/qmetaobject.h>
 #include <QtCore/qsysinfo.h>
 
@@ -74,6 +73,13 @@ bool qt_camera_service_isValid(AVFCameraService *service)
     return true;
 }
 
+enum WriterState
+{
+    WriterStateIdle,
+    WriterStateActive,
+    WriterStateAborted
+};
+
 } // unnamed namespace
 
 @interface QT_MANGLE_NAMESPACE(AVFMediaAssetWriter) (PrivateAPI)
@@ -85,21 +91,14 @@ bool qt_camera_service_isValid(AVFCameraService *service)
 
 @implementation QT_MANGLE_NAMESPACE(AVFMediaAssetWriter)
 
-- (id)initWithQueue:(dispatch_queue_t)writerQueue
-      delegate:(AVFMediaRecorderControlIOS *)delegate
+- (id)initWithDelegate:(AVFMediaRecorderControlIOS *)delegate
 {
-    Q_ASSERT(writerQueue);
     Q_ASSERT(delegate);
 
     if (self = [super init]) {
-        // "Shared" queue:
-        dispatch_retain(writerQueue);
-        m_writerQueue.reset(writerQueue);
-
         m_delegate = delegate;
         m_setStartTime = true;
-        m_stopped.store(true);
-        m_aborted.store(false);
+        m_state.store(WriterStateIdle);
         m_startTime = kCMTimeInvalid;
         m_lastTimeStamp = kCMTimeInvalid;
         m_durationInMs.store(0);
@@ -127,6 +126,12 @@ bool qt_camera_service_isValid(AVFCameraService *service)
     m_audioSettings = audioSettings;
     m_videoSettings = videoSettings;
 
+    m_writerQueue.reset(dispatch_queue_create("asset-writer-queue", DISPATCH_QUEUE_SERIAL));
+    if (!m_writerQueue) {
+        qDebugCamera() << Q_FUNC_INFO << "failed to create an asset writer's queue";
+        return false;
+    }
+
     m_videoQueue.reset(dispatch_queue_create("video-output-queue", DISPATCH_QUEUE_SERIAL));
     if (!m_videoQueue) {
         qDebugCamera() << Q_FUNC_INFO << "failed to create video queue";
@@ -173,15 +178,12 @@ bool qt_camera_service_isValid(AVFCameraService *service)
 
 - (void)start
 {
-    // To be executed on a writer's queue.
-    const QMutexLocker lock(&m_writerMutex);
-    if (m_aborted.load())
-        return;
-
     [self setQueues];
 
     m_setStartTime = true;
-    m_stopped.store(false);
+
+    m_state.storeRelease(WriterStateActive);
+
     [m_assetWriter startWriting];
     AVCaptureSession *session = m_service->session()->captureSession();
     if (!session.running)
@@ -190,27 +192,36 @@ bool qt_camera_service_isValid(AVFCameraService *service)
 
 - (void)stop
 {
-    // To be executed on a writer's queue.
-    {
-    const QMutexLocker lock(&m_writerMutex);
-    if (m_aborted.load())
+    if (m_state.loadAcquire() != WriterStateActive)
         return;
 
-    if (m_stopped.load())
+    if ([m_assetWriter status] != AVAssetWriterStatusWriting)
         return;
 
-    m_stopped.store(true);
-    }
-
+    // Do this here so that -
+    // 1. '-abort' should not try calling finishWriting again and
+    // 2. async block (see below) will know if recorder control was deleted
+    //    before the block's execution:
+    m_state.storeRelease(WriterStateIdle);
+    // Now, since we have to ensure no sample buffers are
+    // appended after a call to finishWriting, we must
+    // ensure writer's queue sees this change in m_state
+    // _before_ we call finishWriting:
+    dispatch_sync(m_writerQueue, ^{});
+    // Done, but now we also want to prevent video queue
+    // from updating our viewfinder:
+    dispatch_sync(m_videoQueue, ^{});
+
+    // Now we're safe to stop:
     [m_assetWriter finishWritingWithCompletionHandler:^{
         // This block is async, so by the time it's executed,
         // it's possible that render control was deleted already ...
-        const QMutexLocker lock(&m_writerMutex);
-        if (m_aborted.load())
+        if (m_state.loadAcquire() == WriterStateAborted)
             return;
 
         AVCaptureSession *session = m_service->session()->captureSession();
-        [session stopRunning];
+        if (session.running)
+            [session stopRunning];
         [session removeOutput:m_audioOutput];
         [session removeInput:m_audioInput];
         QMetaObject::invokeMethod(m_delegate, "assetWriterFinished", Qt::QueuedConnection);
@@ -219,12 +230,26 @@ bool qt_camera_service_isValid(AVFCameraService *service)
 
 - (void)abort
 {
-    // To be executed on any thread (presumably, it's the main thread),
-    // prevents writer from accessing any shared object.
-    const QMutexLocker lock(&m_writerMutex);
-    m_aborted.store(true);
-    if (m_stopped.load())
+    // -abort is to be called from recorder control's dtor.
+
+    if (m_state.fetchAndStoreRelease(WriterStateAborted) != WriterStateActive) {
+        // Not recording, nothing to stop.
         return;
+    }
+
+    // From Apple's docs:
+    // "To guarantee that all sample buffers are successfully written,
+    //  you must ensure that all calls to appendSampleBuffer: and
+    //  appendPixelBuffer:withPresentationTime: have returned before
+    //  invoking this method."
+    //
+    // The only way we can ensure this is:
+    dispatch_sync(m_writerQueue, ^{});
+    // At this point next block (if any) on the writer's queue
+    // will see m_state preventing it from any further processing.
+    dispatch_sync(m_videoQueue, ^{});
+    // After this point video queue will not try to modify our
+    // viewfider, so we're safe to delete now.
 
     [m_assetWriter finishWritingWithCompletionHandler:^{
     }];
@@ -236,13 +261,12 @@ bool qt_camera_service_isValid(AVFCameraService *service)
     Q_ASSERT(m_setStartTime);
     Q_ASSERT(sampleBuffer);
 
-    const QMutexLocker lock(&m_writerMutex);
-    if (m_aborted.load() || m_stopped.load())
+    if (m_state.loadAcquire() != WriterStateActive)
         return;
 
     QMetaObject::invokeMethod(m_delegate, "assetWriterStarted", Qt::QueuedConnection);
 
-    m_durationInMs.store(0);
+    m_durationInMs.storeRelease(0);
     m_startTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
     m_lastTimeStamp = m_startTime;
     [m_assetWriter startSessionAtSourceTime:m_startTime];
@@ -251,10 +275,10 @@ bool qt_camera_service_isValid(AVFCameraService *service)
 
 - (void)writeVideoSampleBuffer:(CMSampleBufferRef)sampleBuffer
 {
+    // This code is executed only on a writer's queue.
     Q_ASSERT(sampleBuffer);
 
-    // This code is executed only on a writer's queue.
-    if (!m_aborted.load() && !m_stopped.load()) {
+    if (m_state.loadAcquire() == WriterStateActive) {
         if (m_setStartTime)
             [self setStartTimeFrom:sampleBuffer];
 
@@ -264,17 +288,15 @@ bool qt_camera_service_isValid(AVFCameraService *service)
         }
     }
 
-
     CFRelease(sampleBuffer);
 }
 
 - (void)writeAudioSampleBuffer:(CMSampleBufferRef)sampleBuffer
 {
-    // This code is executed only on a writer's queue.
-    // it does not touch any shared/external data.
     Q_ASSERT(sampleBuffer);
 
-    if (!m_aborted.load() && !m_stopped.load()) {
+    // This code is executed only on a writer's queue.
+    if (m_state.loadAcquire() == WriterStateActive) {
         if (m_setStartTime)
             [self setStartTimeFrom:sampleBuffer];
 
@@ -293,10 +315,7 @@ bool qt_camera_service_isValid(AVFCameraService *service)
 {
     Q_UNUSED(connection)
 
-    // This method can be called on either video or audio queue,
-    // never on a writer's queue, it needs access to a shared data, so
-    // lock is required.
-    if (m_stopped.load())
+    if (m_state.loadAcquire() != WriterStateActive)
         return;
 
     if (!CMSampleBufferDataIsReady(sampleBuffer)) {
@@ -307,8 +326,7 @@ bool qt_camera_service_isValid(AVFCameraService *service)
     CFRetain(sampleBuffer);
 
     if (captureOutput != m_audioOutput.data()) {
-        const QMutexLocker lock(&m_writerMutex);
-        if (m_aborted.load() || m_stopped.load()) {
+        if (m_state.load() != WriterStateActive) {
             CFRelease(sampleBuffer);
             return;
         }
@@ -447,7 +465,7 @@ bool qt_camera_service_isValid(AVFCameraService *service)
         if (!CMTimeCompare(duration, kCMTimeInvalid))
             return;
 
-        m_durationInMs.store(CMTimeGetSeconds(duration) * 1000);
+        m_durationInMs.storeRelease(CMTimeGetSeconds(duration) * 1000);
         m_lastTimeStamp = newTimeStamp;
     }
 }
diff --git a/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.h b/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.h
index 6736f4639..a0967efa3 100644
--- a/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.h
+++ b/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.h
@@ -97,8 +97,6 @@ private:
     void stopWriter();
 
     AVFCameraService *m_service;
-
-    AVFScopedPointer<dispatch_queue_t> m_writerQueue;
     AVFScopedPointer<QT_MANGLE_NAMESPACE(AVFMediaAssetWriter)> m_writer;
 
     QUrl m_outputLocation;
diff --git a/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.mm b/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.mm
index 7c8725260..5f604e9a0 100644
--- a/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.mm
+++ b/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.mm
@@ -92,13 +92,7 @@ AVFMediaRecorderControlIOS::AVFMediaRecorderControlIOS(AVFCameraService *service
 {
     Q_ASSERT(service);
 
-    m_writerQueue.reset(dispatch_queue_create("asset-writer-queue", DISPATCH_QUEUE_SERIAL));
-    if (!m_writerQueue) {
-        qDebugCamera() << Q_FUNC_INFO << "failed to create an asset writer's queue";
-        return;
-    }
-
-    m_writer.reset([[QT_MANGLE_NAMESPACE(AVFMediaAssetWriter) alloc] initWithQueue:m_writerQueue delegate:this]);
+    m_writer.reset([[QT_MANGLE_NAMESPACE(AVFMediaAssetWriter) alloc] initWithDelegate:this]);
     if (!m_writer) {
         qDebugCamera() << Q_FUNC_INFO << "failed to create an asset writer";
         return;
@@ -295,9 +289,15 @@ void AVFMediaRecorderControlIOS::setState(QMediaRecorder::State state)
             Q_EMIT stateChanged(m_state);
             Q_EMIT statusChanged(m_lastStatus);
 
-            dispatch_async(m_writerQueue, ^{
-                [m_writer start];
-            });
+            // Apple recommends to call startRunning and do all
+            // setup on a special queue, and that's what we had
+            // initially (dispatch_async to writerQueue). Unfortunately,
+            // writer's queue is not the only queue/thread that can
+            // access/modify the session, and as a result we have
+            // all possible data/race-conditions with Obj-C exceptions
+            // at best and something worse in general.
+            // Now we try to only modify session on the same thread.
+            [m_writer start];
         } else {
             [session startRunning];
             Q_EMIT error(QMediaRecorder::FormatError, tr("Failed to start recording"));
@@ -324,7 +324,7 @@ void AVFMediaRecorderControlIOS::setMuted(bool muted)
 
 void AVFMediaRecorderControlIOS::setVolume(qreal volume)
 {
-    Q_UNUSED(volume);
+    Q_UNUSED(volume)
     qDebugCamera() << Q_FUNC_INFO << "not implemented";
 }
 
@@ -409,9 +409,7 @@ void AVFMediaRecorderControlIOS::stopWriter()
         Q_EMIT stateChanged(m_state);
         Q_EMIT statusChanged(m_lastStatus);
 
-        dispatch_async(m_writerQueue, ^{
-            [m_writer stop];
-        });
+        [m_writer stop];
     }
 }
 
diff --git a/src/plugins/directshow/player/directshowplayerservice.cpp b/src/plugins/directshow/player/directshowplayerservice.cpp
index fa5ce3d55..ccc25d30b 100644
--- a/src/plugins/directshow/player/directshowplayerservice.cpp
+++ b/src/plugins/directshow/player/directshowplayerservice.cpp
@@ -552,8 +552,6 @@ void DirectShowPlayerService::doRender(QMutexLocker *locker)
 
         m_executedTasks |= Render;
     }
-
-    m_loop->wake();
 }
 
 void DirectShowPlayerService::doFinalizeLoad(QMutexLocker *locker)
diff --git a/src/plugins/directshow/player/directshowvideorenderercontrol.cpp b/src/plugins/directshow/player/directshowvideorenderercontrol.cpp
index e08ac1f9d..b86125df9 100644
--- a/src/plugins/directshow/player/directshowvideorenderercontrol.cpp
+++ b/src/plugins/directshow/player/directshowvideorenderercontrol.cpp
@@ -52,11 +52,20 @@ DirectShowVideoRendererControl::DirectShowVideoRendererControl(DirectShowEventLo
     , m_loop(loop)
     , m_surface(0)
     , m_filter(0)
+#ifdef HAVE_EVR
+    , m_evrPresenter(0)
+#endif
 {
 }
 
 DirectShowVideoRendererControl::~DirectShowVideoRendererControl()
 {
+#ifdef HAVE_EVR
+    if (m_evrPresenter) {
+        m_evrPresenter->setSurface(Q_NULLPTR);
+        m_evrPresenter->Release();
+    }
+#endif
     if (m_filter)
         m_filter->Release();
 }
@@ -71,6 +80,14 @@ void DirectShowVideoRendererControl::setSurface(QAbstractVideoSurface *surface)
     if (m_surface == surface)
         return;
 
+#ifdef HAVE_EVR
+    if (m_evrPresenter) {
+        m_evrPresenter->setSurface(Q_NULLPTR);
+        m_evrPresenter->Release();
+        m_evrPresenter = 0;
+    }
+#endif
+
     if (m_filter) {
         m_filter->Release();
         m_filter = 0;
@@ -81,12 +98,13 @@ void DirectShowVideoRendererControl::setSurface(QAbstractVideoSurface *surface)
     if (m_surface) {
 #ifdef HAVE_EVR
         m_filter = com_new<IBaseFilter>(clsid_EnhancedVideoRenderer);
-        EVRCustomPresenter *evrPresenter = new EVRCustomPresenter(m_surface);
-        if (!evrPresenter->isValid() || !qt_evr_setCustomPresenter(m_filter, evrPresenter)) {
+        m_evrPresenter = new EVRCustomPresenter(m_surface);
+        if (!m_evrPresenter->isValid() || !qt_evr_setCustomPresenter(m_filter, m_evrPresenter)) {
             m_filter->Release();
             m_filter = 0;
+            m_evrPresenter->Release();
+            m_evrPresenter = 0;
         }
-        evrPresenter->Release();
 
         if (!m_filter)
 #endif
diff --git a/src/plugins/directshow/player/directshowvideorenderercontrol.h b/src/plugins/directshow/player/directshowvideorenderercontrol.h
index 17dd4705b..9d1a23933 100644
--- a/src/plugins/directshow/player/directshowvideorenderercontrol.h
+++ b/src/plugins/directshow/player/directshowvideorenderercontrol.h
@@ -45,6 +45,9 @@
 #include "qvideorenderercontrol.h"
 
 class DirectShowEventLoop;
+#ifdef HAVE_EVR
+class EVRCustomPresenter;
+#endif
 
 QT_USE_NAMESPACE
 
@@ -67,6 +70,9 @@ private:
     DirectShowEventLoop *m_loop;
     QAbstractVideoSurface *m_surface;
     IBaseFilter *m_filter;
+#ifdef HAVE_EVR
+    EVRCustomPresenter *m_evrPresenter;
+#endif
 };
 
 #endif
diff --git a/src/plugins/gstreamer/camerabin/camerabinv4limageprocessing.cpp b/src/plugins/gstreamer/camerabin/camerabinv4limageprocessing.cpp
index d2be15e71..6ca1dbe94 100644
--- a/src/plugins/gstreamer/camerabin/camerabinv4limageprocessing.cpp
+++ b/src/plugins/gstreamer/camerabin/camerabinv4limageprocessing.cpp
@@ -200,8 +200,10 @@ void CameraBinV4LImageProcessing::setParameter(
         const QCameraImageProcessing::WhiteBalanceMode m =
                 value.value<QCameraImageProcessing::WhiteBalanceMode>();
         if (m != QCameraImageProcessing::WhiteBalanceAuto
-                && m != QCameraImageProcessing::WhiteBalanceManual)
+                && m != QCameraImageProcessing::WhiteBalanceManual) {
+            qt_safe_close(fd);
             return;
+        }
 
         control.value = (m == QCameraImageProcessing::WhiteBalanceAuto) ? true : false;
     }
@@ -220,6 +222,7 @@ void CameraBinV4LImageProcessing::setParameter(
         break;
 
     default:
+        qt_safe_close(fd);
         return;
     }
 
diff --git a/src/plugins/qnx/mediaplayer/mmrenderermediaplayercontrol.cpp b/src/plugins/qnx/mediaplayer/mmrenderermediaplayercontrol.cpp
index 87c2c26dc..5cd3bc3d2 100644
--- a/src/plugins/qnx/mediaplayer/mmrenderermediaplayercontrol.cpp
+++ b/src/plugins/qnx/mediaplayer/mmrenderermediaplayercontrol.cpp
@@ -346,6 +346,8 @@ void MmRendererMediaPlayerControl::setState(QMediaPlayer::State state)
 
 void MmRendererMediaPlayerControl::stopInternal(StopCommand stopCommand)
 {
+    setPosition(0);
+
     if (m_state != QMediaPlayer::StoppedState) {
 
         if (stopCommand == StopMmRenderer) {
@@ -355,11 +357,6 @@ void MmRendererMediaPlayerControl::stopInternal(StopCommand stopCommand)
 
         setState(QMediaPlayer::StoppedState);
     }
-
-    if (m_position != 0) {
-        m_position = 0;
-        emit positionChanged(0);
-    }
 }
 
 void MmRendererMediaPlayerControl::setVolume(int volume)
diff --git a/src/plugins/winrt/qwinrtcameracontrol.cpp b/src/plugins/winrt/qwinrtcameracontrol.cpp
index 390364eb8..6ce502b88 100644
--- a/src/plugins/winrt/qwinrtcameracontrol.cpp
+++ b/src/plugins/winrt/qwinrtcameracontrol.cpp
@@ -942,7 +942,8 @@ HRESULT QWinRTCameraControl::initialize()
         Q_ASSERT_SUCCEEDED(hr);
         if (isFocusSupported) {
             hr = advancedVideoDeviceController->get_RegionsOfInterestControl(&d->regionsOfInterestControl);
-            Q_ASSERT_SUCCEEDED(hr);
+            if (FAILED(hr))
+                qCDebug(lcMMCamera) << "Focus supported, but no control for regions of interest available";
             hr = initializeFocus();
             Q_ASSERT_SUCCEEDED(hr);
         } else {