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, 349 insertions, 0 deletions

diff --git a/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.mm b/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.mm
new file mode 100644
index 000000000..b763dbcce
--- /dev/null
+++ b/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.mm
@@ -0,0 +1,349 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd and/or its subsidiary(-ies).
+** 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include "avfmediarecordercontrol_ios.h"
+#include "avfcamerarenderercontrol.h"
+#include "avfcamerasession.h"
+#include "avfcameracontrol.h"
+#include "avfcameraservice.h"
+#include "avfcameradebug.h"
+
+#include <QtCore/qdebug.h>
+
+QT_USE_NAMESPACE
+
+namespace {
+
+bool qt_is_writable_file_URL(NSURL *fileURL)
+{
+    Q_ASSERT(fileURL);
+
+    if (![fileURL isFileURL])
+        return false;
+
+    if (NSString *path = [[fileURL path] stringByExpandingTildeInPath]) {
+        return [[NSFileManager defaultManager]
+                isWritableFileAtPath:[path stringByDeletingLastPathComponent]];
+    }
+
+    return false;
+}
+
+bool qt_file_exists(NSURL *fileURL)
+{
+    Q_ASSERT(fileURL);
+
+    if (NSString *path = [[fileURL path] stringByExpandingTildeInPath])
+        return [[NSFileManager defaultManager] fileExistsAtPath:path];
+
+    return false;
+}
+
+}
+
+AVFMediaRecorderControlIOS::AVFMediaRecorderControlIOS(AVFCameraService *service, QObject *parent)
+    : QMediaRecorderControl(parent)
+    , m_service(service)
+    , m_state(QMediaRecorder::StoppedState)
+    , m_lastStatus(QMediaRecorder::UnloadedStatus)
+{
+    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 delegateQueue:dispatch_get_main_queue()]);
+    if (!m_writer) {
+        qDebugCamera() << Q_FUNC_INFO << "failed to create an asset writer";
+        return;
+    }
+
+    AVFCameraControl *cameraControl = m_service->cameraControl();
+    if (!cameraControl) {
+        qDebugCamera() << Q_FUNC_INFO << "camera control is nil";
+        return;
+    }
+
+    connect(cameraControl, SIGNAL(captureModeChanged(QCamera::CaptureModes)),
+                           SLOT(captureModeChanged(QCamera::CaptureModes)));
+    connect(cameraControl, SIGNAL(statusChanged(QCamera::Status)),
+                           SLOT(cameraStatusChanged(QCamera::Status)));
+}
+
+AVFMediaRecorderControlIOS::~AVFMediaRecorderControlIOS()
+{
+    [m_writer abort];
+}
+
+QUrl AVFMediaRecorderControlIOS::outputLocation() const
+{
+    return m_outputLocation;
+}
+
+bool AVFMediaRecorderControlIOS::setOutputLocation(const QUrl &location)
+{
+    m_outputLocation = location;
+    return location.scheme() == QLatin1String("file") || location.scheme().isEmpty();
+}
+
+QMediaRecorder::State AVFMediaRecorderControlIOS::state() const
+{
+    return m_state;
+}
+
+QMediaRecorder::Status AVFMediaRecorderControlIOS::status() const
+{
+    return m_lastStatus;
+}
+
+qint64 AVFMediaRecorderControlIOS::duration() const
+{
+    return m_writer.data()->m_durationInMs.load();
+}
+
+bool AVFMediaRecorderControlIOS::isMuted() const
+{
+    return false;
+}
+
+qreal AVFMediaRecorderControlIOS::volume() const
+{
+    return 1.;
+}
+
+void AVFMediaRecorderControlIOS::applySettings()
+{
+}
+
+void AVFMediaRecorderControlIOS::setState(QMediaRecorder::State state)
+{
+    Q_ASSERT(m_service->session()
+             && m_service->session()->captureSession());
+
+    if (!m_writer) {
+        qDebugCamera() << Q_FUNC_INFO << "Invalid recorder";
+        return;
+    }
+
+    if (state == m_state)
+        return;
+
+    switch (state) {
+    case QMediaRecorder::RecordingState:
+    {
+        AVFCameraControl *cameraControl = m_service->cameraControl();
+        Q_ASSERT(cameraControl);
+
+        if (!(cameraControl->captureMode() & QCamera::CaptureVideo)) {
+            qDebugCamera() << Q_FUNC_INFO << "wrong capture mode, CaptureVideo expected";
+            Q_EMIT error(QMediaRecorder::ResourceError, tr("Failed to start recording"));
+            return;
+        }
+
+        if (cameraControl->status() != QCamera::ActiveStatus) {
+            qDebugCamera() << Q_FUNC_INFO << "can not start record while camera is not active";
+            Q_EMIT error(QMediaRecorder::ResourceError, tr("Failed to start recording"));
+            return;
+        }
+
+        const QString path(m_outputLocation.scheme() == QLatin1String("file") ?
+                           m_outputLocation.path() : m_outputLocation.toString());
+        const QUrl fileURL(QUrl::fromLocalFile(m_storageLocation.generateFileName(path, QCamera::CaptureVideo,
+                           QLatin1String("clip_"), QLatin1String("mp4"))));
+
+        NSURL *nsFileURL = fileURL.toNSURL();
+        if (!nsFileURL) {
+            qWarning() << Q_FUNC_INFO << "invalid output URL:" << fileURL;
+            Q_EMIT error(QMediaRecorder::ResourceError, tr("Invalid output file URL"));
+            return;
+        }
+        if (!qt_is_writable_file_URL(nsFileURL)) {
+            qWarning() << Q_FUNC_INFO << "invalid output URL:" << fileURL
+                       << "(the location is not writable)";
+            Q_EMIT error(QMediaRecorder::ResourceError, tr("Non-writeable file location"));
+            return;
+        }
+        if (qt_file_exists(nsFileURL)) {
+            // We test for/handle this error here since AWAssetWriter will raise an
+            // Objective-C exception, which is not good at all.
+            qWarning() << Q_FUNC_INFO << "invalid output URL:" << fileURL
+                       << "(file already exists)";
+            Q_EMIT error(QMediaRecorder::ResourceError, tr("File already exists"));
+            return;
+        }
+
+        AVCaptureSession *session = m_service->session()->captureSession();
+        // We stop session now so that no more frames for renderer's queue
+        // generated, will restart in assetWriterStarted.
+        [session stopRunning];
+
+        if ([m_writer setupWithFileURL:nsFileURL cameraService:m_service]) {
+            m_state = QMediaRecorder::RecordingState;
+            m_lastStatus = QMediaRecorder::StartingStatus;
+
+            Q_EMIT actualLocationChanged(fileURL);
+            Q_EMIT stateChanged(m_state);
+            Q_EMIT statusChanged(m_lastStatus);
+
+            dispatch_async(m_writerQueue, ^{
+                [m_writer start];
+            });
+        } else {
+            [session startRunning];
+            Q_EMIT error(QMediaRecorder::FormatError, tr("Failed to start recording"));
+        }
+    } break;
+    case QMediaRecorder::PausedState:
+    {
+        Q_EMIT error(QMediaRecorder::FormatError, tr("Recording pause not supported"));
+        return;
+    } break;
+    case QMediaRecorder::StoppedState:
+    {
+        // Do not check the camera status, we can stop if we started.
+        stopWriter();
+    }
+    }
+}
+
+void AVFMediaRecorderControlIOS::setMuted(bool muted)
+{
+    Q_UNUSED(muted)
+    qDebugCamera() << Q_FUNC_INFO << "not implemented";
+}
+
+void AVFMediaRecorderControlIOS::setVolume(qreal volume)
+{
+    Q_UNUSED(volume);
+    qDebugCamera() << Q_FUNC_INFO << "not implemented";
+}
+
+void AVFMediaRecorderControlIOS::assetWriterStarted()
+{
+    m_lastStatus = QMediaRecorder::RecordingStatus;
+    Q_EMIT statusChanged(QMediaRecorder::RecordingStatus);
+}
+
+void AVFMediaRecorderControlIOS::assetWriterFailedToStart()
+{
+}
+
+void AVFMediaRecorderControlIOS::assetWriterFailedToStop()
+{
+}
+
+void AVFMediaRecorderControlIOS::assetWriterFinished()
+{
+    AVFCameraControl *cameraControl = m_service->cameraControl();
+    Q_ASSERT(cameraControl);
+
+    const QMediaRecorder::Status lastStatus = m_lastStatus;
+
+    if (cameraControl->captureMode() & QCamera::CaptureVideo)
+        m_lastStatus = QMediaRecorder::LoadedStatus;
+    else
+        m_lastStatus = QMediaRecorder::UnloadedStatus;
+
+    m_service->videoOutput()->resetCaptureDelegate();
+    [m_service->session()->captureSession() startRunning];
+
+    if (m_lastStatus != lastStatus)
+        Q_EMIT statusChanged(m_lastStatus);
+}
+
+void AVFMediaRecorderControlIOS::captureModeChanged(QCamera::CaptureModes newMode)
+{
+    AVFCameraControl *cameraControl = m_service->cameraControl();
+    Q_ASSERT(cameraControl);
+
+    const QMediaRecorder::Status lastStatus = m_lastStatus;
+
+    if (newMode & QCamera::CaptureVideo) {
+        if (cameraControl->status() == QCamera::ActiveStatus)
+            m_lastStatus = QMediaRecorder::LoadedStatus;
+    } else {
+        if (m_lastStatus == QMediaRecorder::RecordingStatus)
+           return stopWriter();
+        else
+            m_lastStatus = QMediaRecorder::UnloadedStatus;
+    }
+
+    if (m_lastStatus != lastStatus)
+        Q_EMIT statusChanged(m_lastStatus);
+}
+
+void AVFMediaRecorderControlIOS::cameraStatusChanged(QCamera::Status newStatus)
+{
+    AVFCameraControl *cameraControl = m_service->cameraControl();
+    Q_ASSERT(cameraControl);
+
+    const QMediaRecorder::Status lastStatus = m_lastStatus;
+    const bool isCapture = cameraControl->captureMode() & QCamera::CaptureVideo;
+    if (newStatus == QCamera::StartingStatus) {
+        if (isCapture && m_lastStatus == QMediaRecorder::UnloadedStatus)
+            m_lastStatus = QMediaRecorder::LoadingStatus;
+    } else if (newStatus == QCamera::ActiveStatus) {
+        if (isCapture && m_lastStatus == QMediaRecorder::LoadingStatus)
+            m_lastStatus = QMediaRecorder::LoadedStatus;
+    } else {
+        if (m_lastStatus == QMediaRecorder::RecordingStatus)
+            return stopWriter();
+        if (newStatus == QCamera::UnloadedStatus)
+            m_lastStatus = QMediaRecorder::UnloadedStatus;
+    }
+
+    if (lastStatus != m_lastStatus)
+        Q_EMIT statusChanged(m_lastStatus);
+}
+
+void AVFMediaRecorderControlIOS::stopWriter()
+{
+    if (m_lastStatus == QMediaRecorder::RecordingStatus) {
+        m_state = QMediaRecorder::StoppedState;
+        m_lastStatus = QMediaRecorder::FinalizingStatus;
+
+        Q_EMIT stateChanged(m_state);
+        Q_EMIT statusChanged(m_lastStatus);
+
+        dispatch_async(m_writerQueue, ^{
+            [m_writer stop];
+        });
+    }
+}
+
+#include "moc_avfmediarecordercontrol_ios.cpp"