Video asset writer for iOS

AVFoundation on iOS lacks the ability to use AVCaptureVideoDataOutput and
AVCaptureMovieFileOutput simultaneously. Right now viewfinder stops working
as soon as we add movie file output. The only workaround
we have now is to write video/audio 'maually' - creating asset writer
and feeding it with audio/video samples.

Change-Id: I33a63546783279c545f0433b5051287269825d3f
Task-number: QTBUG-37655
Reviewed-by: Yoann Lopes <yoann.lopes@theqtcompany.com>

1 files changed, 119 insertions, 0 deletions

diff --git a/src/plugins/avfoundation/camera/avfmediaassetwriter.h b/src/plugins/avfoundation/camera/avfmediaassetwriter.h
new file mode 100644
index 000000000..eae700751
--- /dev/null
+++ b/src/plugins/avfoundation/camera/avfmediaassetwriter.h
@@ -0,0 +1,119 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef AVFMEDIAASSETWRITER_H
+#define AVFMEDIAASSETWRITER_H
+
+#include "avfcamerautility.h"
+
+#include <QtCore/qglobal.h>
+#include <QtCore/qatomic.h>
+#include <QtCore/qmutex.h>
+
+#include <AVFoundation/AVFoundation.h>
+
+QT_BEGIN_NAMESPACE
+
+class AVFCameraService;
+
+class AVFMediaAssetWriterDelegate
+{
+public:
+    virtual ~AVFMediaAssetWriterDelegate();
+
+    virtual void assetWriterStarted() = 0;
+    virtual void assetWriterFailedToStart() = 0;
+    virtual void assetWriterFailedToStop() = 0;
+    virtual void assetWriterFinished() = 0;
+};
+
+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>
+{
+@private
+    AVFCameraService *m_service;
+
+    QT_MANGLE_NAMESPACE(AVFScopedPointer)<AVAssetWriterInput> m_cameraWriterInput;
+    QT_MANGLE_NAMESPACE(AVFScopedPointer)<AVCaptureDeviceInput> m_audioInput;
+    QT_MANGLE_NAMESPACE(AVFScopedPointer)<AVCaptureAudioDataOutput> m_audioOutput;
+    QT_MANGLE_NAMESPACE(AVFScopedPointer)<AVAssetWriterInput> m_audioWriterInput;
+
+    // High priority serial queue for video output:
+    QT_MANGLE_NAMESPACE(AVFScopedPointer)<dispatch_queue_t> m_videoQueue;
+    // Serial queue for audio output:
+    QT_MANGLE_NAMESPACE(AVFScopedPointer)<dispatch_queue_t> m_audioQueue;
+    // Queue to write sample buffers:
+    __weak dispatch_queue_t m_writerQueue;
+
+    QT_MANGLE_NAMESPACE(AVFScopedPointer)<AVAssetWriter> m_assetWriter;
+    // Delegate's queue.
+    __weak dispatch_queue_t m_delegateQueue;
+    // TODO: QPointer??
+    QT_PREPEND_NAMESPACE(AVFMediaAssetWriterDelegate) *m_delegate;
+
+    bool m_setStartTime;
+    QT_MANGLE_NAMESPACE(AVFAtomicBool) m_stopped;
+    bool m_stoppedInternal;
+    bool m_aborted;
+
+    QT_MANGLE_NAMESPACE(QMutex) m_writerMutex;
+@public
+    QT_MANGLE_NAMESPACE(AVFAtomicInt64) m_durationInMs;
+@private
+    CMTime m_startTime;
+    CMTime m_lastTimeStamp;
+}
+
+- (id)initWithQueue:(dispatch_queue_t)writerQueue
+      delegate:(QT_PREPEND_NAMESPACE(AVFMediaAssetWriterDelegate) *)delegate
+      delegateQueue:(dispatch_queue_t)delegateQueue;
+
+- (bool)setupWithFileURL:(NSURL *)fileURL
+        cameraService:(QT_PREPEND_NAMESPACE(AVFCameraService) *)service;
+
+- (void)start;
+- (void)stop;
+// This to be called if control's dtor gets called,
+// on the control's thread.
+- (void)abort;
+
+@end
+
+#endif // AVFMEDIAASSETWRITER_H