feather/contrib/depends/patches/qt/v4l2.patch

diff --git a/src/plugins/multimedia/CMakeLists.txt b/src/plugins/multimedia/CMakeLists.txt
index 978710112..1cb2cc730 100644
--- a/src/plugins/multimedia/CMakeLists.txt
+++ b/src/plugins/multimedia/CMakeLists.txt
@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 
 if (QT_FEATURE_ffmpeg)
-    add_subdirectory(ffmpeg)
+    add_subdirectory(v4l2)
 endif ()
 if (QT_FEATURE_gstreamer)
     add_subdirectory(gstreamer)
diff --git a/src/plugins/multimedia/v4l2/CMakeLists.txt b/src/plugins/multimedia/v4l2/CMakeLists.txt
new file mode 100644
index 000000000..7c7e1a8da
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/CMakeLists.txt
@@ -0,0 +1,22 @@
+qt_internal_add_plugin(QFFmpegMediaPlugin
+    OUTPUT_NAME ffmpegmediaplugin
+    PLUGIN_TYPE multimedia
+    SOURCES
+        qffmpegmediametadata.cpp qffmpegmediametadata_p.h
+        qffmpegvideosink.cpp qffmpegvideosink_p.h
+        qffmpegmediaformatinfo.cpp qffmpegmediaformatinfo_p.h
+        qffmpegmediaintegration.cpp qffmpegmediaintegration_p.h
+        qffmpegimagecapture.cpp qffmpegimagecapture_p.h
+        qffmpegmediacapturesession.cpp qffmpegmediacapturesession_p.h
+    DEFINES
+        QT_COMPILING_FFMPEG
+    LIBRARIES
+        Qt::MultimediaPrivate
+        Qt::CorePrivate
+)
+
+qt_internal_extend_target(QFFmpegMediaPlugin CONDITION QT_FEATURE_linux_v4l
+    SOURCES
+        qv4l2camera.cpp qv4l2camera_p.h
+)
+
diff --git a/src/plugins/multimedia/v4l2/ffmpeg.json b/src/plugins/multimedia/v4l2/ffmpeg.json
new file mode 100644
index 000000000..d8e7e4456
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/ffmpeg.json
@@ -0,0 +1,3 @@
+{
+    "Keys": [ "ffmpeg" ]
+}
diff --git a/src/plugins/multimedia/v4l2/qffmpegimagecapture.cpp b/src/plugins/multimedia/v4l2/qffmpegimagecapture.cpp
new file mode 100644
index 000000000..9ee4e1db8
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegimagecapture.cpp
@@ -0,0 +1,269 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qffmpegimagecapture_p.h"
+#include <private/qplatformmediaformatinfo_p.h>
+#include <private/qplatformcamera_p.h>
+#include <private/qplatformimagecapture_p.h>
+#include <qvideoframeformat.h>
+#include <private/qmediastoragelocation_p.h>
+#include <qimagewriter.h>
+
+#include <QtCore/QDebug>
+#include <QtCore/QDir>
+#include <qstandardpaths.h>
+
+#include <qloggingcategory.h>
+
+QT_BEGIN_NAMESPACE
+
+Q_LOGGING_CATEGORY(qLcImageCapture, "qt.multimedia.imageCapture")
+
+QFFmpegImageCapture::QFFmpegImageCapture(QImageCapture *parent)
+  : QPlatformImageCapture(parent)
+{
+}
+
+QFFmpegImageCapture::~QFFmpegImageCapture()
+{
+}
+
+bool QFFmpegImageCapture::isReadyForCapture() const
+{
+    return m_isReadyForCapture;
+}
+
+static const char *extensionForFormat(QImageCapture::FileFormat format)
+{
+    const char *fmt = "jpg";
+    switch (format) {
+    case QImageCapture::UnspecifiedFormat:
+    case QImageCapture::JPEG:
+        fmt = "jpg";
+        break;
+    case QImageCapture::PNG:
+        fmt = "png";
+        break;
+    case QImageCapture::WebP:
+        fmt = "webp";
+        break;
+    case QImageCapture::Tiff:
+        fmt = "tiff";
+        break;
+    }
+    return fmt;
+}
+
+int QFFmpegImageCapture::capture(const QString &fileName)
+{
+    QString path = QMediaStorageLocation::generateFileName(fileName, QStandardPaths::PicturesLocation, QLatin1String(extensionForFormat(m_settings.format())));
+    return doCapture(path);
+}
+
+int QFFmpegImageCapture::captureToBuffer()
+{
+    return doCapture(QString());
+}
+
+int QFFmpegImageCapture::doCapture(const QString &fileName)
+{
+    qCDebug(qLcImageCapture) << "do capture";
+    if (!m_session) {
+        //emit error in the next event loop,
+        //so application can associate it with returned request id.
+        QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
+                                  Q_ARG(int, -1),
+                                  Q_ARG(int, QImageCapture::ResourceError),
+                                  Q_ARG(QString, QPlatformImageCapture::msgImageCaptureNotSet()));
+
+        qCDebug(qLcImageCapture) << "error 1";
+        return -1;
+    }
+    if (!m_camera) {
+        //emit error in the next event loop,
+        //so application can associate it with returned request id.
+        QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
+                                  Q_ARG(int, -1),
+                                  Q_ARG(int, QImageCapture::ResourceError),
+                                  Q_ARG(QString,tr("No camera available.")));
+
+        qCDebug(qLcImageCapture) << "error 2";
+        return -1;
+    }
+    if (passImage) {
+        //emit error in the next event loop,
+        //so application can associate it with returned request id.
+        QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
+                                  Q_ARG(int, -1),
+                                  Q_ARG(int, QImageCapture::NotReadyError),
+                                  Q_ARG(QString, QPlatformImageCapture::msgCameraNotReady()));
+
+        qCDebug(qLcImageCapture) << "error 3";
+        return -1;
+    }
+    m_lastId++;
+
+    pendingImages.enqueue({m_lastId, fileName, QMediaMetaData{}});
+    // let one image pass the pipeline
+    passImage = true;
+
+    updateReadyForCapture();
+    return m_lastId;
+}
+
+void QFFmpegImageCapture::setCaptureSession(QPlatformMediaCaptureSession *session)
+{
+    auto *captureSession = static_cast<QFFmpegMediaCaptureSession *>(session);
+    if (m_session == captureSession)
+        return;
+
+    if (m_session) {
+        disconnect(m_session, nullptr, this, nullptr);
+        m_lastId = 0;
+        pendingImages.clear();
+        passImage = false;
+        cameraActive = false;
+    }
+
+    m_session = captureSession;
+    if (m_session)
+        connect(m_session, &QPlatformMediaCaptureSession::cameraChanged, this, &QFFmpegImageCapture::onCameraChanged);
+
+    onCameraChanged();
+    updateReadyForCapture();
+}
+
+void QFFmpegImageCapture::updateReadyForCapture()
+{
+    bool ready = m_session && !passImage && cameraActive;
+    if (ready == m_isReadyForCapture)
+        return;
+    m_isReadyForCapture = ready;
+    emit readyForCaptureChanged(m_isReadyForCapture);
+}
+
+void QFFmpegImageCapture::cameraActiveChanged(bool active)
+{
+    qCDebug(qLcImageCapture) << "cameraActiveChanged" << cameraActive << active;
+    if (cameraActive == active)
+        return;
+    cameraActive = active;
+    qCDebug(qLcImageCapture) << "isReady" << isReadyForCapture();
+    updateReadyForCapture();
+}
+
+void QFFmpegImageCapture::newVideoFrame(const QVideoFrame &frame)
+{
+    if (!passImage)
+        return;
+
+    passImage = false;
+    Q_ASSERT(!pendingImages.isEmpty());
+    auto pending = pendingImages.dequeue();
+
+    emit imageExposed(pending.id);
+    // ### Add metadata from the AVFrame
+    emit imageMetadataAvailable(pending.id, pending.metaData);
+    emit imageAvailable(pending.id, frame);
+    QImage image = frame.toImage();
+    if (m_settings.resolution().isValid() && m_settings.resolution() != image.size())
+        image = image.scaled(m_settings.resolution());
+
+    emit imageCaptured(pending.id, image);
+    if (!pending.filename.isEmpty()) {
+        const char *fmt = nullptr;
+        switch (m_settings.format()) {
+        case QImageCapture::UnspecifiedFormat:
+        case QImageCapture::JPEG:
+            fmt = "jpeg";
+            break;
+        case QImageCapture::PNG:
+            fmt = "png";
+            break;
+        case QImageCapture::WebP:
+            fmt = "webp";
+            break;
+        case QImageCapture::Tiff:
+            fmt = "tiff";
+            break;
+        }
+        int quality = -1;
+        switch (m_settings.quality()) {
+        case QImageCapture::VeryLowQuality:
+            quality = 25;
+            break;
+        case QImageCapture::LowQuality:
+            quality = 50;
+            break;
+        case QImageCapture::NormalQuality:
+            break;
+        case QImageCapture::HighQuality:
+            quality = 75;
+            break;
+        case QImageCapture::VeryHighQuality:
+            quality = 99;
+            break;
+        }
+
+        QImageWriter writer(pending.filename, fmt);
+        writer.setQuality(quality);
+
+        if (writer.write(image)) {
+            emit imageSaved(pending.id, pending.filename);
+        } else {
+            QImageCapture::Error err = QImageCapture::ResourceError;
+            if (writer.error() == QImageWriter::UnsupportedFormatError)
+                err = QImageCapture::FormatError;
+            emit error(pending.id, err, writer.errorString());
+        }
+    }
+    updateReadyForCapture();
+}
+
+void QFFmpegImageCapture::onCameraChanged()
+{
+    auto *camera = m_session ? m_session->camera() : nullptr;
+    if (m_camera == camera)
+        return;
+
+    if (m_camera)
+        disconnect(m_camera);
+
+    m_camera = camera;
+
+    if (camera) {
+        cameraActiveChanged(camera->isActive());
+        connect(camera, &QPlatformCamera::activeChanged, this, &QFFmpegImageCapture::cameraActiveChanged);
+        connect(camera, &QPlatformCamera::newVideoFrame, this, &QFFmpegImageCapture::newVideoFrame);
+    } else {
+        cameraActiveChanged(false);
+    }
+}
+
+QImageEncoderSettings QFFmpegImageCapture::imageSettings() const
+{
+    return m_settings;
+}
+
+void QFFmpegImageCapture::setImageSettings(const QImageEncoderSettings &settings)
+{
+    auto s = settings;
+    const auto supportedFormats = QPlatformMediaIntegration::instance()->formatInfo()->imageFormats;
+    if (supportedFormats.isEmpty()) {
+        emit error(-1, QImageCapture::FormatError, "No image formats supported, can't capture.");
+        return;
+    }
+    if (s.format() == QImageCapture::UnspecifiedFormat) {
+        auto f = QImageCapture::JPEG;
+        if (!supportedFormats.contains(f))
+            f = supportedFormats.first();
+        s.setFormat(f);
+    } else if (!supportedFormats.contains(settings.format())) {
+        emit error(-1, QImageCapture::FormatError, "Image format not supported.");
+        return;
+    }
+
+    m_settings = settings;
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/multimedia/v4l2/qffmpegimagecapture_p.h b/src/plugins/multimedia/v4l2/qffmpegimagecapture_p.h
new file mode 100644
index 000000000..de54fe7cb
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegimagecapture_p.h
@@ -0,0 +1,72 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+
+#ifndef QFFMPEGIMAGECAPTURE_H
+#define QFFMPEGIMAGECAPTURE_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qplatformimagecapture_p.h>
+#include "qffmpegmediacapturesession_p.h"
+
+#include <qqueue.h>
+
+QT_BEGIN_NAMESPACE
+
+class QFFmpegImageCapture : public QPlatformImageCapture
+
+{
+    Q_OBJECT
+public:
+    QFFmpegImageCapture(QImageCapture *parent);
+    virtual ~QFFmpegImageCapture();
+
+    bool isReadyForCapture() const override;
+    int capture(const QString &fileName) override;
+    int captureToBuffer() override;
+
+    QImageEncoderSettings imageSettings() const override;
+    void setImageSettings(const QImageEncoderSettings &settings) override;
+
+    void setCaptureSession(QPlatformMediaCaptureSession *session);
+
+    void updateReadyForCapture();
+
+public Q_SLOTS:
+    void cameraActiveChanged(bool active);
+    void newVideoFrame(const QVideoFrame &frame);
+    void onCameraChanged();
+
+private:
+    int doCapture(const QString &fileName);
+
+    QFFmpegMediaCaptureSession *m_session = nullptr;
+    int m_lastId = 0;
+    QImageEncoderSettings m_settings;
+    QPlatformCamera *m_camera = nullptr;
+
+    struct PendingImage {
+        int id;
+        QString filename;
+        QMediaMetaData metaData;
+    };
+
+    QQueue<PendingImage> pendingImages;
+    bool passImage = false;
+    bool cameraActive = false;
+    bool m_isReadyForCapture = false;
+};
+
+QT_END_NAMESPACE
+
+#endif // QGSTREAMERCAPTURECORNTROL_H
diff --git a/src/plugins/multimedia/v4l2/qffmpegmediacapturesession.cpp b/src/plugins/multimedia/v4l2/qffmpegmediacapturesession.cpp
new file mode 100644
index 000000000..b6865761c
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegmediacapturesession.cpp
@@ -0,0 +1,114 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qffmpegmediacapturesession_p.h"
+
+#include "private/qplatformaudioinput_p.h"
+#include "private/qplatformaudiooutput_p.h"
+#include "qffmpegimagecapture_p.h"
+#include "private/qplatformcamera_p.h"
+#include "qvideosink.h"
+
+#include <qloggingcategory.h>
+
+QT_BEGIN_NAMESPACE
+
+Q_LOGGING_CATEGORY(qLcMediaCapture, "qt.multimedia.capture")
+
+
+
+QFFmpegMediaCaptureSession::QFFmpegMediaCaptureSession()
+{
+}
+
+QFFmpegMediaCaptureSession::~QFFmpegMediaCaptureSession()
+{
+}
+
+QPlatformCamera *QFFmpegMediaCaptureSession::camera()
+{
+    return m_camera;
+}
+
+void QFFmpegMediaCaptureSession::setCamera(QPlatformCamera *camera)
+{
+    if (m_camera == camera)
+        return;
+    if (m_camera) {
+        m_camera->disconnect(this);
+        m_camera->setCaptureSession(nullptr);
+    }
+
+    m_camera = camera;
+
+    if (m_camera) {
+        connect(m_camera, &QPlatformCamera::newVideoFrame, this, &QFFmpegMediaCaptureSession::newVideoFrame);
+        m_camera->setCaptureSession(this);
+    }
+
+    emit cameraChanged();
+}
+
+QPlatformImageCapture *QFFmpegMediaCaptureSession::imageCapture()
+{
+    return m_imageCapture;
+}
+
+void QFFmpegMediaCaptureSession::setImageCapture(QPlatformImageCapture *imageCapture)
+{
+    if (m_imageCapture == imageCapture)
+        return;
+
+    if (m_imageCapture)
+        m_imageCapture->setCaptureSession(nullptr);
+
+    m_imageCapture = static_cast<QFFmpegImageCapture *>(imageCapture);
+
+    if (m_imageCapture)
+        m_imageCapture->setCaptureSession(this);
+
+    emit imageCaptureChanged();
+}
+
+void QFFmpegMediaCaptureSession::setMediaRecorder(QPlatformMediaRecorder *recorder)
+{
+    return;
+}
+
+QPlatformMediaRecorder *QFFmpegMediaCaptureSession::mediaRecorder()
+{
+    return nullptr;
+}
+
+void QFFmpegMediaCaptureSession::setAudioInput(QPlatformAudioInput *input)
+{
+    if (m_audioInput == input)
+        return;
+
+    m_audioInput = input;
+}
+
+void QFFmpegMediaCaptureSession::setVideoPreview(QVideoSink *sink)
+{
+    if (m_videoSink == sink)
+        return;
+
+    m_videoSink = sink;
+}
+
+void QFFmpegMediaCaptureSession::setAudioOutput(QPlatformAudioOutput *output)
+{
+    if (m_audioOutput == output)
+        return;
+
+    m_audioOutput = output;
+}
+
+void QFFmpegMediaCaptureSession::newVideoFrame(const QVideoFrame &frame)
+{
+    if (m_videoSink)
+        m_videoSink->setVideoFrame(frame);
+}
+
+
+QT_END_NAMESPACE
diff --git a/src/plugins/multimedia/v4l2/qffmpegmediacapturesession_p.h b/src/plugins/multimedia/v4l2/qffmpegmediacapturesession_p.h
new file mode 100644
index 000000000..858a537cc
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegmediacapturesession_p.h
@@ -0,0 +1,63 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QFFMPEGMEDIACAPTURESESSION_H
+#define QFFMPEGMEDIACAPTURESESSION_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qplatformmediacapture_p.h>
+#include <private/qplatformmediaintegration_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QFFmpegMediaRecorder;
+class QFFmpegImageCapture;
+class QVideoFrame;
+
+class QFFmpegMediaCaptureSession : public QPlatformMediaCaptureSession
+{
+    Q_OBJECT
+
+public:
+    QFFmpegMediaCaptureSession();
+    virtual ~QFFmpegMediaCaptureSession();
+
+    QPlatformCamera *camera() override;
+    void setCamera(QPlatformCamera *camera) override;
+
+    QPlatformImageCapture *imageCapture() override;
+    void setImageCapture(QPlatformImageCapture *imageCapture) override;
+
+    QPlatformMediaRecorder *mediaRecorder() override;
+    void setMediaRecorder(QPlatformMediaRecorder *recorder) override;
+
+    void setAudioInput(QPlatformAudioInput *input) override;
+    QPlatformAudioInput *audioInput() { return m_audioInput; }
+
+    void setVideoPreview(QVideoSink *sink) override;
+    void setAudioOutput(QPlatformAudioOutput *output) override;
+
+public Q_SLOTS:
+    void newVideoFrame(const QVideoFrame &frame);
+
+private:
+    QPlatformCamera *m_camera = nullptr;
+    QPlatformAudioInput *m_audioInput = nullptr;
+    QFFmpegImageCapture *m_imageCapture = nullptr;
+    QPlatformAudioOutput *m_audioOutput = nullptr;
+    QVideoSink *m_videoSink = nullptr;
+};
+
+QT_END_NAMESPACE
+
+#endif // QGSTREAMERCAPTURESERVICE_H
diff --git a/src/plugins/multimedia/v4l2/qffmpegmediaformatinfo.cpp b/src/plugins/multimedia/v4l2/qffmpegmediaformatinfo.cpp
new file mode 100644
index 000000000..00b838d50
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegmediaformatinfo.cpp
@@ -0,0 +1,32 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qffmpegmediaformatinfo_p.h"
+#include "qaudioformat.h"
+#include "qimagewriter.h"
+
+QT_BEGIN_NAMESPACE
+
+QFFmpegMediaFormatInfo::QFFmpegMediaFormatInfo()
+{
+    // Add image formats we support. We currently simply use Qt's built-in image write
+    // to save images. That doesn't give us HDR support or support for larger bit depths,
+    // but most cameras can currently not generate those anyway.
+    const auto imgFormats = QImageWriter::supportedImageFormats();
+    for (const auto &f : imgFormats) {
+        if (f == "png")
+            imageFormats.append(QImageCapture::PNG);
+        else if (f == "jpeg")
+            imageFormats.append(QImageCapture::JPEG);
+        else if (f == "tiff")
+            imageFormats.append(QImageCapture::Tiff);
+        else if (f == "webp")
+            imageFormats.append(QImageCapture::WebP);
+    }
+
+}
+
+QFFmpegMediaFormatInfo::~QFFmpegMediaFormatInfo() = default;
+
+
+QT_END_NAMESPACE
diff --git a/src/plugins/multimedia/v4l2/qffmpegmediaformatinfo_p.h b/src/plugins/multimedia/v4l2/qffmpegmediaformatinfo_p.h
new file mode 100644
index 000000000..e34005bbf
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegmediaformatinfo_p.h
@@ -0,0 +1,34 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QFFmpegMediaFormatInfo_H
+#define QFFmpegMediaFormatInfo_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API. It exists purely as an
+// implementation detail. This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qplatformmediaformatinfo_p.h>
+#include <qhash.h>
+#include <qlist.h>
+#include <qaudioformat.h>
+
+QT_BEGIN_NAMESPACE
+
+class QFFmpegMediaFormatInfo : public QPlatformMediaFormatInfo
+{
+public:
+    QFFmpegMediaFormatInfo();
+    ~QFFmpegMediaFormatInfo();
+};
+
+QT_END_NAMESPACE
+
+#endif
diff --git a/src/plugins/multimedia/v4l2/qffmpegmediaintegration.cpp b/src/plugins/multimedia/v4l2/qffmpegmediaintegration.cpp
new file mode 100644
index 000000000..c07c0ebc7
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegmediaintegration.cpp
@@ -0,0 +1,130 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include <QtMultimedia/private/qplatformmediaplugin_p.h>
+#include <qcameradevice.h>
+#include "qffmpegmediaintegration_p.h"
+#include "qffmpegmediaformatinfo_p.h"
+#include "qffmpegvideosink_p.h"
+#include "qffmpegmediacapturesession_p.h"
+#include "qffmpegimagecapture_p.h"
+
+#ifdef Q_OS_MACOS
+#include <VideoToolbox/VideoToolbox.h>
+#endif
+
+#ifdef Q_OS_DARWIN
+#include "qavfcamera_p.h"
+#elif defined(Q_OS_WINDOWS)
+#include "qwindowscamera_p.h"
+#include "qwindowsvideodevices_p.h"
+#endif
+
+#if QT_CONFIG(linux_v4l)
+#include "qv4l2camera_p.h"
+#endif
+
+QT_BEGIN_NAMESPACE
+
+class QFFmpegMediaPlugin : public QPlatformMediaPlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID QPlatformMediaPlugin_iid FILE "ffmpeg.json")
+
+public:
+    QFFmpegMediaPlugin()
+      : QPlatformMediaPlugin()
+    {}
+
+    QPlatformMediaIntegration* create(const QString &name) override
+    {
+        if (name == QLatin1String("ffmpeg"))
+            return new QFFmpegMediaIntegration;
+        return nullptr;
+    }
+};
+
+QFFmpegMediaIntegration::QFFmpegMediaIntegration()
+{
+    m_formatsInfo = new QFFmpegMediaFormatInfo();
+
+#if QT_CONFIG(linux_v4l)
+    m_videoDevices = std::make_unique<QV4L2CameraDevices>(this);
+#endif
+#ifdef Q_OS_DARWIN
+    m_videoDevices = std::make_unique<QAVFVideoDevices>(this);
+#elif defined(Q_OS_WINDOWS)
+    m_videoDevices = std::make_unique<QWindowsVideoDevices>(this);
+#endif
+
+#ifndef QT_NO_DEBUG
+    qDebug() << "Available HW decoding frameworks:";
+    AVHWDeviceType type = AV_HWDEVICE_TYPE_NONE;
+    while ((type = av_hwdevice_iterate_types(type)) != AV_HWDEVICE_TYPE_NONE)
+        qDebug() << "    " << av_hwdevice_get_type_name(type);
+#endif
+}
+
+QFFmpegMediaIntegration::~QFFmpegMediaIntegration()
+{
+    delete m_formatsInfo;
+}
+
+QPlatformMediaFormatInfo *QFFmpegMediaIntegration::formatInfo()
+{
+    return m_formatsInfo;
+}
+
+QMaybe<QPlatformMediaCaptureSession *> QFFmpegMediaIntegration::createCaptureSession()
+{
+    return new QFFmpegMediaCaptureSession();
+}
+
+QMaybe<QPlatformCamera *> QFFmpegMediaIntegration::createCamera(QCamera *camera)
+{
+#ifdef Q_OS_DARWIN
+    return new QAVFCamera(camera);
+#elif QT_CONFIG(linux_v4l)
+    return new QV4L2Camera(camera);
+#elif defined(Q_OS_WINDOWS)
+    return new QWindowsCamera(camera);
+#else
+    Q_UNUSED(camera);
+    return nullptr;//new QFFmpegCamera(camera);
+#endif
+}
+
+QMaybe<QPlatformImageCapture *> QFFmpegMediaIntegration::createImageCapture(QImageCapture *imageCapture)
+{
+    return new QFFmpegImageCapture(imageCapture);
+}
+
+QMaybe<QPlatformVideoSink *> QFFmpegMediaIntegration::createVideoSink(QVideoSink *sink)
+{
+    return new QFFmpegVideoSink(sink);
+}
+
+#ifdef Q_OS_ANDROID
+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
+    void *environment;
+    if (vm->GetEnv(&environment, JNI_VERSION_1_6))
+        return JNI_ERR;
+
+    // setting our javavm into ffmpeg.
+    if (av_jni_set_java_vm(vm, nullptr))
+        return JNI_ERR;
+
+    return JNI_VERSION_1_6;
+}
+#endif
+
+QT_END_NAMESPACE
+
+#include "qffmpegmediaintegration.moc"
diff --git a/src/plugins/multimedia/v4l2/qffmpegmediaintegration_p.h b/src/plugins/multimedia/v4l2/qffmpegmediaintegration_p.h
new file mode 100644
index 000000000..8b44da741
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegmediaintegration_p.h
@@ -0,0 +1,43 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QGSTREAMERINTEGRATION_H
+#define QGSTREAMERINTEGRATION_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API. It exists purely as an
+// implementation detail. This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qplatformmediaintegration_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QFFmpegMediaFormatInfo;
+
+class QFFmpegMediaIntegration : public QPlatformMediaIntegration
+{
+public:
+    QFFmpegMediaIntegration();
+    ~QFFmpegMediaIntegration();
+
+    static QFFmpegMediaIntegration *instance() { return static_cast<QFFmpegMediaIntegration *>(QPlatformMediaIntegration::instance()); }
+    QPlatformMediaFormatInfo *formatInfo() override;
+
+    QMaybe<QPlatformMediaCaptureSession *> createCaptureSession() override;
+    QMaybe<QPlatformCamera *> createCamera(QCamera *) override;
+    QMaybe<QPlatformImageCapture *> createImageCapture(QImageCapture *) override;
+    QMaybe<QPlatformVideoSink *> createVideoSink(QVideoSink *sink) override;
+
+    QFFmpegMediaFormatInfo *m_formatsInfo = nullptr;
+};
+
+QT_END_NAMESPACE
+
+#endif
diff --git a/src/plugins/multimedia/v4l2/qffmpegmediametadata.cpp b/src/plugins/multimedia/v4l2/qffmpegmediametadata.cpp
new file mode 100644
index 000000000..dda577d44
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegmediametadata.cpp
@@ -0,0 +1,72 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qffmpegmediametadata_p.h"
+#include <QDebug>
+#include <QtCore/qdatetime.h>
+#include <qstringlist.h>
+#include <qurl.h>
+#include <qlocale.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace  {
+
+struct {
+    const char *tag;
+    QMediaMetaData::Key key;
+} ffmpegTagToMetaDataKey[] = {
+    { "title", QMediaMetaData::Title },
+    { "comment", QMediaMetaData::Comment },
+    { "description", QMediaMetaData::Description },
+    { "genre", QMediaMetaData::Genre },
+    { "date", QMediaMetaData::Date },
+    { "year", QMediaMetaData::Date },
+    { "creation_time", QMediaMetaData::Date },
+
+    { "language", QMediaMetaData::Language },
+
+    { "copyright", QMediaMetaData::Copyright },
+
+    // Music
+    { "album", QMediaMetaData::AlbumTitle },
+    { "album_artist", QMediaMetaData::AlbumArtist },
+    { "artist", QMediaMetaData::ContributingArtist },
+    { "track", QMediaMetaData::TrackNumber },
+
+    // Movie
+    { "performer", QMediaMetaData::LeadPerformer },
+
+    { nullptr, QMediaMetaData::Title }
+};
+
+}
+
+static QMediaMetaData::Key tagToKey(const char *tag)
+{
+    auto *map = ffmpegTagToMetaDataKey;
+    while (map->tag) {
+        if (!strcmp(map->tag, tag))
+            return map->key;
+        ++map;
+    }
+    return QMediaMetaData::Key(-1);
+}
+
+static const char *keyToTag(QMediaMetaData::Key key)
+{
+    auto *map = ffmpegTagToMetaDataKey;
+    while (map->tag) {
+        if (map->key == key)
+            return map->tag;
+        ++map;
+    }
+    return nullptr;
+}
+
+QByteArray QFFmpegMetaData::value(const QMediaMetaData &metaData, QMediaMetaData::Key key)
+{
+    return {};
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/multimedia/v4l2/qffmpegmediametadata_p.h b/src/plugins/multimedia/v4l2/qffmpegmediametadata_p.h
new file mode 100644
index 000000000..95b069b64
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegmediametadata_p.h
@@ -0,0 +1,30 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QFFMPEGMEDIAMETADATA_H
+#define QFFMPEGMEDIAMETADATA_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <qmediametadata.h>
+
+QT_BEGIN_NAMESPACE
+
+class QFFmpegMetaData : public QMediaMetaData
+{
+public:
+    static QByteArray value(const QMediaMetaData &metaData, QMediaMetaData::Key key);
+};
+
+QT_END_NAMESPACE
+
+#endif // QFFMPEGMEDIAMETADATA_H
diff --git a/src/plugins/multimedia/v4l2/qffmpegvideosink.cpp b/src/plugins/multimedia/v4l2/qffmpegvideosink.cpp
new file mode 100644
index 000000000..93e7ceeed
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegvideosink.cpp
@@ -0,0 +1,17 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+#include <qffmpegvideosink_p.h>
+
+QT_BEGIN_NAMESPACE
+
+QFFmpegVideoSink::QFFmpegVideoSink(QVideoSink *sink)
+    : QPlatformVideoSink(sink)
+{
+}
+
+void QFFmpegVideoSink::setVideoFrame(const QVideoFrame &frame)
+{
+    QPlatformVideoSink::setVideoFrame(frame);
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/multimedia/v4l2/qffmpegvideosink_p.h b/src/plugins/multimedia/v4l2/qffmpegvideosink_p.h
new file mode 100644
index 000000000..cbaa810d7
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qffmpegvideosink_p.h
@@ -0,0 +1,39 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QFFMPEGVIDEOSINK_H
+#define QFFMPEGVIDEOSINK_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qplatformvideosink_p.h>
+//#include <qffmpeghwaccel_p.h>
+
+QT_BEGIN_NAMESPACE
+
+// Required for QDoc workaround
+class QString;
+
+class QFFmpegVideoSink : public QPlatformVideoSink
+{
+    Q_OBJECT
+
+public:
+    QFFmpegVideoSink(QVideoSink *sink);
+
+    void setVideoFrame(const QVideoFrame &frame) override;
+};
+
+QT_END_NAMESPACE
+
+
+#endif
diff --git a/src/plugins/multimedia/v4l2/qv4l2camera.cpp b/src/plugins/multimedia/v4l2/qv4l2camera.cpp
new file mode 100644
index 000000000..0f7a8c91a
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qv4l2camera.cpp
@@ -0,0 +1,940 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qv4l2camera_p.h"
+
+#include <qdir.h>
+#include <qmutex.h>
+#include <qendian.h>
+#include <private/qcameradevice_p.h>
+#include <private/qabstractvideobuffer_p.h>
+#include <private/qvideotexturehelper_p.h>
+#include <private/qmultimediautils_p.h>
+#include <private/qplatformmediadevices_p.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <private/qcore_unix_p.h>
+#include <sys/mman.h>
+
+#include <linux/videodev2.h>
+
+#include <qloggingcategory.h>
+
+QT_BEGIN_NAMESPACE
+
+Q_LOGGING_CATEGORY(qLV4L2Camera, "qt.multimedia.ffmpeg.v4l2camera");
+
+QV4L2CameraDevices::QV4L2CameraDevices(QPlatformMediaIntegration *integration)
+    : QPlatformVideoDevices(integration)
+{
+    deviceWatcher.addPath(QLatin1String("/dev"));
+    connect(&deviceWatcher, &QFileSystemWatcher::directoryChanged, this, &QV4L2CameraDevices::checkCameras);
+    doCheckCameras();
+}
+
+QList<QCameraDevice> QV4L2CameraDevices::videoDevices() const
+{
+    return cameras;
+}
+
+void QV4L2CameraDevices::checkCameras()
+{
+    doCheckCameras();
+    videoInputsChanged();
+}
+
+const struct {
+    QVideoFrameFormat::PixelFormat fmt;
+    uint32_t v4l2Format;
+} formatMap[] = {
+    // ### How do we handle V4L2_PIX_FMT_H264 and V4L2_PIX_FMT_MPEG4?
+    { QVideoFrameFormat::Format_YUV420P,  V4L2_PIX_FMT_YUV420  },
+    { QVideoFrameFormat::Format_YUV422P,  V4L2_PIX_FMT_YUV422P },
+    { QVideoFrameFormat::Format_YUYV,     V4L2_PIX_FMT_YUYV    },
+    { QVideoFrameFormat::Format_UYVY,     V4L2_PIX_FMT_UYVY    },
+    { QVideoFrameFormat::Format_XBGR8888, V4L2_PIX_FMT_XBGR32  },
+    { QVideoFrameFormat::Format_XRGB8888, V4L2_PIX_FMT_XRGB32  },
+    { QVideoFrameFormat::Format_ABGR8888, V4L2_PIX_FMT_ABGR32  },
+    { QVideoFrameFormat::Format_ARGB8888, V4L2_PIX_FMT_ARGB32  },
+    { QVideoFrameFormat::Format_BGRX8888, V4L2_PIX_FMT_BGR32   },
+    { QVideoFrameFormat::Format_RGBX8888, V4L2_PIX_FMT_RGB32   },
+    { QVideoFrameFormat::Format_BGRA8888, V4L2_PIX_FMT_BGRA32  },
+    { QVideoFrameFormat::Format_RGBA8888, V4L2_PIX_FMT_RGBA32  },
+    { QVideoFrameFormat::Format_Y8,       V4L2_PIX_FMT_GREY    },
+    { QVideoFrameFormat::Format_Y16,      V4L2_PIX_FMT_Y16     },
+    { QVideoFrameFormat::Format_NV12,     V4L2_PIX_FMT_NV12    },
+    { QVideoFrameFormat::Format_NV21,     V4L2_PIX_FMT_NV21    },
+    { QVideoFrameFormat::Format_Jpeg,     V4L2_PIX_FMT_MJPEG   },
+    { QVideoFrameFormat::Format_Jpeg,     V4L2_PIX_FMT_JPEG    },
+    { QVideoFrameFormat::Format_Invalid,  0                    },
+};
+
+static QVideoFrameFormat::PixelFormat formatForV4L2Format(uint32_t v4l2Format)
+{
+    auto *f = formatMap;
+    while (f->v4l2Format) {
+        if (f->v4l2Format == v4l2Format)
+            return f->fmt;
+        ++f;
+    }
+    return QVideoFrameFormat::Format_Invalid;
+}
+
+static uint32_t v4l2FormatForPixelFormat(QVideoFrameFormat::PixelFormat format)
+{
+    auto *f = formatMap;
+    while (f->v4l2Format) {
+        if (f->fmt == format)
+            return f->v4l2Format;
+        ++f;
+    }
+    return 0;
+}
+
+
+void QV4L2CameraDevices::doCheckCameras()
+{
+    cameras.clear();
+
+    QDir dir(QLatin1String("/dev"));
+    const auto devices = dir.entryList(QDir::System);
+
+    bool first = true;
+
+    for (auto device : devices) {
+//        qCDebug(qLV4L2Camera) << "device:" << device;
+        if (!device.startsWith(QLatin1String("video")))
+            continue;
+
+        QByteArray file = QFile::encodeName(dir.filePath(device));
+        int fd = open(file.constData(), O_RDONLY);
+        if (fd < 0)
+            continue;
+
+        QCameraDevicePrivate *camera = nullptr;
+        v4l2_fmtdesc formatDesc = {};
+
+        struct v4l2_capability cap;
+        if (ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0)
+            goto fail;
+
+        if (cap.device_caps & V4L2_CAP_META_CAPTURE)
+            goto fail;
+        if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE))
+            goto fail;
+        if (!(cap.capabilities & V4L2_CAP_STREAMING))
+            goto fail;
+
+        camera = new QCameraDevicePrivate;
+        camera->id = file;
+        camera->description = QString::fromUtf8((const char *)cap.card);
+//        qCDebug(qLV4L2Camera) << "found camera" << camera->id << camera->description;
+
+        formatDesc.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+
+        while (!ioctl(fd, VIDIOC_ENUM_FMT, &formatDesc)) {
+            auto pixelFmt = formatForV4L2Format(formatDesc.pixelformat);
+            qCDebug(qLV4L2Camera) << "    " << pixelFmt;
+
+            if (pixelFmt == QVideoFrameFormat::Format_Invalid) {
+                ++formatDesc.index;
+                continue;
+            }
+
+//            qCDebug(qLV4L2Camera) << "frame sizes:";
+            v4l2_frmsizeenum frameSize = {};
+            frameSize.pixel_format = formatDesc.pixelformat;
+
+            while (!ioctl(fd, VIDIOC_ENUM_FRAMESIZES, &frameSize)) {
+                if (frameSize.type != V4L2_FRMSIZE_TYPE_DISCRETE)
+                    continue;
+
+                QSize resolution(frameSize.discrete.width, frameSize.discrete.height);
+                float min = 1e10;
+                float max = 0;
+
+                v4l2_frmivalenum frameInterval = {};
+                frameInterval.pixel_format = formatDesc.pixelformat;
+                frameInterval.width = frameSize.discrete.width;
+                frameInterval.height = frameSize.discrete.height;
+
+                while (!ioctl(fd, VIDIOC_ENUM_FRAMEINTERVALS, &frameInterval)) {
+                    if (frameInterval.type != V4L2_FRMIVAL_TYPE_DISCRETE)
+                        continue;
+                    ++frameInterval.index;
+                    float rate = float(frameInterval.discrete.denominator)/float(frameInterval.discrete.numerator);
+                    if (rate > max)
+                        max = rate;
+                    if (rate < min)
+                        min = rate;
+                }
+
+//                qCDebug(qLV4L2Camera) << "    " << resolution << min << max;
+                ++frameSize.index;
+
+                if (min <= max) {
+                    QCameraFormatPrivate *fmt = new QCameraFormatPrivate;
+                    fmt->pixelFormat = pixelFmt;
+                    fmt->resolution = resolution;
+                    fmt->minFrameRate = min;
+                    fmt->maxFrameRate = max;
+                    camera->videoFormats.append(fmt->create());
+                    camera->photoResolutions.append(resolution);
+                }
+            }
+
+            ++formatDesc.index;
+        }
+
+        // first camera is default
+        camera->isDefault = first;
+        first = false;
+
+        cameras.append(camera->create());
+
+        close(fd);
+        continue;
+
+      fail:
+        if (camera)
+              delete camera;
+        close(fd);
+    }
+}
+
+class QV4L2VideoBuffer : public QAbstractVideoBuffer
+{
+public:
+    QV4L2VideoBuffer(QV4L2CameraBuffers *d, int index)
+        : QAbstractVideoBuffer(QVideoFrame::NoHandle, nullptr)
+        , index(index)
+        , d(d)
+    {}
+    ~QV4L2VideoBuffer()
+    {
+        d->release(index);
+    }
+
+    QVideoFrame::MapMode mapMode() const override { return m_mode; }
+    MapData map(QVideoFrame::MapMode mode) override {
+        m_mode = mode;
+        return d->v4l2FileDescriptor >= 0 ? data : MapData{};
+    }
+    void unmap() override {
+        m_mode = QVideoFrame::NotMapped;
+    }
+
+    QVideoFrame::MapMode m_mode = QVideoFrame::NotMapped;
+    MapData data;
+    int index = 0;
+    QExplicitlySharedDataPointer<QV4L2CameraBuffers> d;
+};
+
+QV4L2CameraBuffers::~QV4L2CameraBuffers()
+{
+    QMutexLocker locker(&mutex);
+    Q_ASSERT(v4l2FileDescriptor < 0);
+    unmapBuffers();
+}
+
+
+
+void QV4L2CameraBuffers::release(int index)
+{
+    QMutexLocker locker(&mutex);
+    if (v4l2FileDescriptor < 0 || index >= mappedBuffers.size())
+        return;
+
+    struct v4l2_buffer buf = {};
+
+    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    buf.memory = V4L2_MEMORY_MMAP;
+    buf.index = index;
+
+    if (ioctl(v4l2FileDescriptor, VIDIOC_QBUF, &buf) < 0)
+        qWarning() << "Couldn't release V4L2 buffer" << errno << strerror(errno) << index;
+}
+
+void QV4L2CameraBuffers::unmapBuffers()
+{
+    for (const auto &b : std::as_const(mappedBuffers))
+        munmap(b.data, b.size);
+    mappedBuffers.clear();
+}
+
+QV4L2Camera::QV4L2Camera(QCamera *camera)
+    : QPlatformCamera(camera)
+{
+}
+
+QV4L2Camera::~QV4L2Camera()
+{
+    setActive(false);
+    stopCapturing();
+    closeV4L2Fd();
+}
+
+bool QV4L2Camera::isActive() const
+{
+    return m_active;
+}
+
+void QV4L2Camera::setActive(bool active)
+{
+    if (m_active == active)
+        return;
+    if (m_cameraDevice.isNull() && active)
+        return;
+
+    if (m_cameraFormat.isNull())
+        resolveCameraFormat({});
+
+    m_active = active;
+    if (m_active) {
+        setV4L2CameraFormat();
+        initMMap();
+        startCapturing();
+    } else {
+        stopCapturing();
+    }
+    emit newVideoFrame({});
+
+    emit activeChanged(active);
+}
+
+void QV4L2Camera::setCamera(const QCameraDevice &camera)
+{
+    if (m_cameraDevice == camera)
+        return;
+    if (m_active)
+        stopCapturing();
+
+    closeV4L2Fd();
+
+    m_cameraDevice = camera;
+    resolveCameraFormat({});
+
+    initV4L2Controls();
+
+    if (m_active) {
+        setV4L2CameraFormat();
+        initMMap();
+        startCapturing();
+    }
+}
+
+bool QV4L2Camera::setCameraFormat(const QCameraFormat &format)
+{
+    if (!format.isNull() && !m_cameraDevice.videoFormats().contains(format))
+        return false;
+
+    if (!resolveCameraFormat(format))
+        return true;
+
+    if (m_active) {
+        stopCapturing();
+        closeV4L2Fd();
+        initV4L2Controls();
+        setV4L2CameraFormat();
+        initMMap();
+        startCapturing();
+    }
+
+    return true;
+}
+
+bool QV4L2Camera::resolveCameraFormat(const QCameraFormat &format)
+{
+    auto fmt = format;
+    if (fmt.isNull())
+        fmt = findBestCameraFormat(m_cameraDevice);
+
+    if (fmt == m_cameraFormat)
+        return false;
+
+    m_cameraFormat = fmt;
+    return true;
+}
+
+void QV4L2Camera::setFocusMode(QCamera::FocusMode mode)
+{
+    if (mode == focusMode())
+        return;
+
+    bool focusDist = supportedFeatures() & QCamera::Feature::FocusDistance;
+    if (!focusDist && !v4l2RangedFocus)
+        return;
+
+    switch (mode) {
+    default:
+    case QCamera::FocusModeAuto:
+        setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 1);
+        if (v4l2RangedFocus)
+            setV4L2Parameter(V4L2_CID_AUTO_FOCUS_RANGE, V4L2_AUTO_FOCUS_RANGE_AUTO);
+        break;
+    case QCamera::FocusModeAutoNear:
+        setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 1);
+        if (v4l2RangedFocus)
+            setV4L2Parameter(V4L2_CID_AUTO_FOCUS_RANGE, V4L2_AUTO_FOCUS_RANGE_MACRO);
+        else if (focusDist)
+            setV4L2Parameter(V4L2_CID_FOCUS_ABSOLUTE, v4l2MinFocus);
+        break;
+    case QCamera::FocusModeAutoFar:
+        setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 1);
+        if (v4l2RangedFocus)
+            setV4L2Parameter(V4L2_CID_AUTO_FOCUS_RANGE, V4L2_AUTO_FOCUS_RANGE_INFINITY);
+        break;
+    case QCamera::FocusModeInfinity:
+        setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 0);
+        setV4L2Parameter(V4L2_CID_FOCUS_ABSOLUTE, v4l2MaxFocus);
+        break;
+    case QCamera::FocusModeManual:
+        setV4L2Parameter(V4L2_CID_FOCUS_AUTO, 0);
+        setFocusDistance(focusDistance());
+        break;
+    }
+    focusModeChanged(mode);
+}
+
+void QV4L2Camera::setFocusDistance(float d)
+{
+    int distance = v4l2MinFocus + int((v4l2MaxFocus - v4l2MinFocus)*d);
+    setV4L2Parameter(V4L2_CID_FOCUS_ABSOLUTE, distance);
+    focusDistanceChanged(d);
+}
+
+void QV4L2Camera::zoomTo(float factor, float)
+{
+    if (v4l2MaxZoom == v4l2MinZoom)
+        return;
+    factor = qBound(1., factor, 2.);
+    int zoom = v4l2MinZoom + (factor - 1.)*(v4l2MaxZoom - v4l2MinZoom);
+    setV4L2Parameter(V4L2_CID_ZOOM_ABSOLUTE, zoom);
+    zoomFactorChanged(factor);
+}
+
+bool QV4L2Camera::isFocusModeSupported(QCamera::FocusMode mode) const
+{
+    if (supportedFeatures() & QCamera::Feature::FocusDistance &&
+        (mode == QCamera::FocusModeManual || mode == QCamera::FocusModeAutoNear || mode == QCamera::FocusModeInfinity))
+        return true;
+
+    return mode == QCamera::FocusModeAuto;
+}
+
+void QV4L2Camera::setFlashMode(QCamera::FlashMode mode)
+{
+    if (!v4l2FlashSupported || mode == QCamera::FlashOn)
+        return;
+    setV4L2Parameter(V4L2_CID_FLASH_LED_MODE, mode == QCamera::FlashAuto ? V4L2_FLASH_LED_MODE_FLASH : V4L2_FLASH_LED_MODE_NONE);
+    flashModeChanged(mode);
+}
+
+bool QV4L2Camera::isFlashModeSupported(QCamera::FlashMode mode) const
+{
+    if (v4l2FlashSupported && mode == QCamera::FlashAuto)
+        return true;
+    return mode == QCamera::FlashOff;
+}
+
+bool QV4L2Camera::isFlashReady() const
+{
+    struct v4l2_queryctrl queryControl;
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_AUTO_WHITE_BALANCE;
+
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0)
+        return true;
+
+    return false;
+}
+
+void QV4L2Camera::setTorchMode(QCamera::TorchMode mode)
+{
+    if (!v4l2TorchSupported || mode == QCamera::TorchOn)
+        return;
+    setV4L2Parameter(V4L2_CID_FLASH_LED_MODE, mode == QCamera::TorchOn ? V4L2_FLASH_LED_MODE_TORCH : V4L2_FLASH_LED_MODE_NONE);
+    torchModeChanged(mode);
+}
+
+bool QV4L2Camera::isTorchModeSupported(QCamera::TorchMode mode) const
+{
+    if (mode == QCamera::TorchOn)
+        return v4l2TorchSupported;
+    return mode == QCamera::TorchOff;
+}
+
+void QV4L2Camera::setExposureMode(QCamera::ExposureMode mode)
+{
+    if (v4l2AutoExposureSupported && v4l2ManualExposureSupported) {
+        if (mode != QCamera::ExposureAuto && mode != QCamera::ExposureManual)
+            return;
+        int value = QCamera::ExposureAuto ? V4L2_EXPOSURE_AUTO : V4L2_EXPOSURE_MANUAL;
+        setV4L2Parameter(V4L2_CID_EXPOSURE_AUTO, value);
+        exposureModeChanged(mode);
+        return;
+    }
+}
+
+bool QV4L2Camera::isExposureModeSupported(QCamera::ExposureMode mode) const
+{
+    if (mode == QCamera::ExposureAuto)
+        return true;
+    if (v4l2ManualExposureSupported && v4l2AutoExposureSupported)
+        return mode == QCamera::ExposureManual;
+    return false;
+}
+
+void QV4L2Camera::setExposureCompensation(float compensation)
+{
+    if ((v4l2MinExposureAdjustment != 0 || v4l2MaxExposureAdjustment != 0)) {
+        int value = qBound(v4l2MinExposureAdjustment, (int)(compensation*1000), v4l2MaxExposureAdjustment);
+        setV4L2Parameter(V4L2_CID_AUTO_EXPOSURE_BIAS, value);
+        exposureCompensationChanged(value/1000.);
+        return;
+    }
+}
+
+void QV4L2Camera::setManualIsoSensitivity(int iso)
+{
+    if (!(supportedFeatures() & QCamera::Feature::IsoSensitivity))
+        return;
+    setV4L2Parameter(V4L2_CID_ISO_SENSITIVITY_AUTO, iso <= 0 ? V4L2_ISO_SENSITIVITY_AUTO : V4L2_ISO_SENSITIVITY_MANUAL);
+    if (iso > 0) {
+        iso = qBound(minIso(), iso, maxIso());
+        setV4L2Parameter(V4L2_CID_ISO_SENSITIVITY, iso);
+    }
+    return;
+}
+
+int QV4L2Camera::isoSensitivity() const
+{
+    if (!(supportedFeatures() & QCamera::Feature::IsoSensitivity))
+        return -1;
+    return getV4L2Parameter(V4L2_CID_ISO_SENSITIVITY);
+}
+
+void QV4L2Camera::setManualExposureTime(float secs)
+{
+    if (v4l2ManualExposureSupported && v4l2AutoExposureSupported) {
+        int exposure = qBound(v4l2MinExposure, qRound(secs*10000.), v4l2MaxExposure);
+        setV4L2Parameter(V4L2_CID_EXPOSURE_ABSOLUTE, exposure);
+        exposureTimeChanged(exposure/10000.);
+        return;
+    }
+}
+
+float QV4L2Camera::exposureTime() const
+{
+    return getV4L2Parameter(V4L2_CID_EXPOSURE_ABSOLUTE)/10000.;
+}
+
+bool QV4L2Camera::isWhiteBalanceModeSupported(QCamera::WhiteBalanceMode mode) const
+{
+    if (v4l2AutoWhiteBalanceSupported && v4l2ColorTemperatureSupported)
+        return true;
+
+    return mode == QCamera::WhiteBalanceAuto;
+}
+
+void QV4L2Camera::setWhiteBalanceMode(QCamera::WhiteBalanceMode mode)
+{
+    Q_ASSERT(isWhiteBalanceModeSupported(mode));
+
+    int temperature = colorTemperatureForWhiteBalance(mode);
+    int t = setV4L2ColorTemperature(temperature);
+    if (t == 0)
+        mode = QCamera::WhiteBalanceAuto;
+    whiteBalanceModeChanged(mode);
+}
+
+void QV4L2Camera::setColorTemperature(int temperature)
+{
+    if (temperature == 0) {
+        setWhiteBalanceMode(QCamera::WhiteBalanceAuto);
+        return;
+    }
+
+    Q_ASSERT(isWhiteBalanceModeSupported(QCamera::WhiteBalanceManual));
+
+    int t = setV4L2ColorTemperature(temperature);
+    if (t)
+        colorTemperatureChanged(t);
+}
+
+void QV4L2Camera::readFrame()
+{
+    if (!d)
+        return;
+
+    v4l2_buffer buf = {};
+    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    buf.memory = V4L2_MEMORY_MMAP;
+
+    if (ioctl(d->v4l2FileDescriptor, VIDIOC_DQBUF, &buf) < 0) {
+        if (errno == ENODEV) {
+            // camera got removed while being active
+            stopCapturing();
+            closeV4L2Fd();
+            return;
+        }
+        if (errno != EAGAIN)
+            qWarning() << "error calling VIDIOC_DQBUF" << errno << strerror(errno);
+    }
+
+    Q_ASSERT(qsizetype(buf.index) < d->mappedBuffers.size());
+    int i = buf.index;
+
+//    auto textureDesc = QVideoTextureHelper::textureDescription(m_format.pixelFormat());
+
+    QV4L2VideoBuffer *buffer = new QV4L2VideoBuffer(d.get(), i);
+    buffer->data.nPlanes = 1;
+    buffer->data.bytesPerLine[0] = bytesPerLine;
+    buffer->data.data[0] = (uchar *)d->mappedBuffers.at(i).data;
+    buffer->data.size[0] = d->mappedBuffers.at(i).size;
+    QVideoFrameFormat fmt(m_cameraFormat.resolution(), m_cameraFormat.pixelFormat());
+    fmt.setColorSpace(colorSpace);
+//    qCDebug(qLV4L2Camera) << "got a frame" << d->mappedBuffers.at(i).data << d->mappedBuffers.at(i).size << fmt << i;
+    QVideoFrame frame(buffer, fmt);
+
+    if (firstFrameTime.tv_sec == -1)
+        firstFrameTime = buf.timestamp;
+    qint64 secs = buf.timestamp.tv_sec - firstFrameTime.tv_sec;
+    qint64 usecs = buf.timestamp.tv_usec - firstFrameTime.tv_usec;
+    frame.setStartTime(secs*1000000 + usecs);
+    frame.setEndTime(frame.startTime() + frameDuration);
+
+    emit newVideoFrame(frame);
+}
+
+void QV4L2Camera::setCameraBusy()
+{
+    cameraBusy = true;
+    error(QCamera::CameraError, tr("Camera is in use."));
+}
+
+void QV4L2Camera::initV4L2Controls()
+{
+    v4l2AutoWhiteBalanceSupported = false;
+    v4l2ColorTemperatureSupported = false;
+    v4l2RangedFocus = false;
+    v4l2FlashSupported = false;
+    v4l2TorchSupported = false;
+    QCamera::Features features;
+
+
+    const QByteArray deviceName = m_cameraDevice.id();
+    Q_ASSERT(!deviceName.isEmpty());
+
+    closeV4L2Fd();
+    Q_ASSERT(!d);
+
+    d = new QV4L2CameraBuffers;
+
+    d->v4l2FileDescriptor = qt_safe_open(deviceName.constData(), O_RDWR);
+    if (d->v4l2FileDescriptor == -1) {
+        qWarning() << "Unable to open the camera" << deviceName
+                   << "for read to query the parameter info:" << qt_error_string(errno);
+        return;
+    }
+    qCDebug(qLV4L2Camera) << "FD=" << d->v4l2FileDescriptor;
+
+    struct v4l2_queryctrl queryControl;
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_AUTO_WHITE_BALANCE;
+
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2AutoWhiteBalanceSupported = true;
+        setV4L2Parameter(V4L2_CID_AUTO_WHITE_BALANCE, true);
+    }
+
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_WHITE_BALANCE_TEMPERATURE;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2MinColorTemp = queryControl.minimum;
+        v4l2MaxColorTemp = queryControl.maximum;
+        v4l2ColorTemperatureSupported = true;
+        features |= QCamera::Feature::ColorTemperature;
+    }
+
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_EXPOSURE_AUTO;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2AutoExposureSupported = true;
+    }
+
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_EXPOSURE_ABSOLUTE;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2ManualExposureSupported = true;
+        v4l2MinExposure = queryControl.minimum;
+        v4l2MaxExposure = queryControl.maximum;
+        features |= QCamera::Feature::ManualExposureTime;
+    }
+
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_AUTO_EXPOSURE_BIAS;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2MinExposureAdjustment = queryControl.minimum;
+        v4l2MaxExposureAdjustment = queryControl.maximum;
+        features |= QCamera::Feature::ExposureCompensation;
+    }
+
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_ISO_SENSITIVITY_AUTO;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        queryControl.id = V4L2_CID_ISO_SENSITIVITY;
+        if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+            features |= QCamera::Feature::IsoSensitivity;
+            minIsoChanged(queryControl.minimum);
+            maxIsoChanged(queryControl.minimum);
+        }
+    }
+
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_FOCUS_ABSOLUTE;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2MinExposureAdjustment = queryControl.minimum;
+        v4l2MaxExposureAdjustment = queryControl.maximum;
+        features |= QCamera::Feature::FocusDistance;
+    }
+
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_AUTO_FOCUS_RANGE;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2RangedFocus = true;
+    }
+
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_FLASH_LED_MODE;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2FlashSupported = queryControl.minimum <= V4L2_FLASH_LED_MODE_FLASH && queryControl.maximum >= V4L2_FLASH_LED_MODE_FLASH;
+        v4l2TorchSupported = queryControl.minimum <= V4L2_FLASH_LED_MODE_TORCH && queryControl.maximum >= V4L2_FLASH_LED_MODE_TORCH;
+    }
+
+    v4l2MinZoom = 0;
+    v4l2MaxZoom = 0;
+    ::memset(&queryControl, 0, sizeof(queryControl));
+    queryControl.id = V4L2_CID_ZOOM_ABSOLUTE;
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYCTRL, &queryControl) == 0) {
+        v4l2MinZoom = queryControl.minimum;
+        v4l2MaxZoom = queryControl.maximum;
+    }
+    // zoom factors are in arbitrary units, so we simply normalize them to go from 1 to 2
+    // if they are different
+    minimumZoomFactorChanged(1);
+    maximumZoomFactorChanged(v4l2MinZoom != v4l2MaxZoom ? 2 : 1);
+
+    supportedFeaturesChanged(features);
+}
+
+void QV4L2Camera::closeV4L2Fd()
+{
+    if (d && d->v4l2FileDescriptor >= 0) {
+        QMutexLocker locker(&d->mutex);
+        d->unmapBuffers();
+        qt_safe_close(d->v4l2FileDescriptor);
+        d->v4l2FileDescriptor = -1;
+    }
+    d = nullptr;
+}
+
+int QV4L2Camera::setV4L2ColorTemperature(int temperature)
+{
+    struct v4l2_control control;
+    ::memset(&control, 0, sizeof(control));
+
+    if (v4l2AutoWhiteBalanceSupported) {
+        setV4L2Parameter(V4L2_CID_AUTO_WHITE_BALANCE, temperature == 0 ? true : false);
+    } else if (temperature == 0) {
+        temperature = 5600;
+    }
+
+    if (temperature != 0 && v4l2ColorTemperatureSupported) {
+        temperature = qBound(v4l2MinColorTemp, temperature, v4l2MaxColorTemp);
+        if (!setV4L2Parameter(V4L2_CID_WHITE_BALANCE_TEMPERATURE, qBound(v4l2MinColorTemp, temperature, v4l2MaxColorTemp)))
+            temperature = 0;
+    } else {
+        temperature = 0;
+    }
+
+    return temperature;
+}
+
+bool QV4L2Camera::setV4L2Parameter(quint32 id, qint32 value)
+{
+    struct v4l2_control control{id, value};
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_S_CTRL, &control) != 0) {
+        qWarning() << "Unable to set the V4L2 Parameter" << Qt::hex << id << "to" << value << qt_error_string(errno);
+        return false;
+    }
+    return true;
+}
+
+int QV4L2Camera::getV4L2Parameter(quint32 id) const
+{
+    struct v4l2_control control{id, 0};
+    if (::ioctl(d->v4l2FileDescriptor, VIDIOC_G_CTRL, &control) != 0) {
+        qWarning() << "Unable to get the V4L2 Parameter" << Qt::hex << id << qt_error_string(errno);
+        return 0;
+    }
+    return control.value;
+}
+
+void QV4L2Camera::setV4L2CameraFormat()
+{
+    Q_ASSERT(!m_cameraFormat.isNull());
+    qCDebug(qLV4L2Camera) << "XXXXX" << this << m_cameraDevice.id() << m_cameraFormat.pixelFormat() << m_cameraFormat.resolution();
+
+    v4l2_format fmt = {};
+    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+
+    auto size = m_cameraFormat.resolution();
+    fmt.fmt.pix.width = size.width();
+    fmt.fmt.pix.height = size.height();
+    fmt.fmt.pix.pixelformat = v4l2FormatForPixelFormat(m_cameraFormat.pixelFormat());
+    fmt.fmt.pix.field = V4L2_FIELD_ANY;
+
+    qCDebug(qLV4L2Camera) << "setting camera format to" << size;
+
+    if (ioctl(d->v4l2FileDescriptor, VIDIOC_S_FMT, &fmt) < 0) {
+        if (errno == EBUSY) {
+            setCameraBusy();
+            return;
+        }
+        qWarning() << "Couldn't set video format on v4l2 camera" << strerror(errno);
+    }
+
+    bytesPerLine = fmt.fmt.pix.bytesperline;
+
+    switch (v4l2_colorspace(fmt.fmt.pix.colorspace)) {
+    default:
+    case V4L2_COLORSPACE_DCI_P3:
+        colorSpace = QVideoFrameFormat::ColorSpace_Undefined;
+        break;
+    case V4L2_COLORSPACE_REC709:
+        colorSpace = QVideoFrameFormat::ColorSpace_BT709;
+        break;
+    case V4L2_COLORSPACE_JPEG:
+        colorSpace = QVideoFrameFormat::ColorSpace_AdobeRgb;
+        break;
+    case V4L2_COLORSPACE_SRGB:
+        // ##### is this correct???
+        colorSpace = QVideoFrameFormat::ColorSpace_BT601;
+        break;
+    case V4L2_COLORSPACE_BT2020:
+        colorSpace = QVideoFrameFormat::ColorSpace_BT2020;
+        break;
+    }
+
+    v4l2_streamparm streamParam = {};
+    streamParam.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+
+    streamParam.parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
+    auto [num, den] = qRealToFraction(1./m_cameraFormat.maxFrameRate());
+    streamParam.parm.capture.timeperframe = { (uint)num, (uint)den };
+    ioctl(d->v4l2FileDescriptor, VIDIOC_S_PARM, &streamParam);
+
+    frameDuration = 1000000*streamParam.parm.capture.timeperframe.numerator
+                    /streamParam.parm.capture.timeperframe.denominator;
+}
+
+void QV4L2Camera::initMMap()
+{
+    if (cameraBusy)
+        return;
+
+    v4l2_requestbuffers req = {};
+    req.count = 4;
+    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    req.memory = V4L2_MEMORY_MMAP;
+
+    if (ioctl(d->v4l2FileDescriptor, VIDIOC_REQBUFS, &req) < 0) {
+        if (errno == EBUSY)
+            setCameraBusy();
+        qWarning() << "requesting mmap'ed buffers failed" << strerror(errno);
+        return;
+    }
+
+    if (req.count < 2) {
+        qWarning() << "Can't map 2 or more buffers";
+        return;
+    }
+
+    for (uint32_t n = 0; n < req.count; ++n) {
+        v4l2_buffer buf = {};
+        buf.index = n;
+        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        buf.memory = V4L2_MEMORY_MMAP;
+
+        if (ioctl(d->v4l2FileDescriptor, VIDIOC_QUERYBUF, &buf) != 0) {
+            qWarning() << "Can't map buffer" << n;
+            return;
+        }
+
+        QV4L2CameraBuffers::MappedBuffer buffer;
+        buffer.size = buf.length;
+        buffer.data = mmap(NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED,
+                           d->v4l2FileDescriptor, buf.m.offset);
+
+        if (buffer.data == MAP_FAILED) {
+            qWarning() << "mmap failed" << n << buf.length << buf.m.offset;
+            return;
+        }
+
+        d->mappedBuffers.append(buffer);
+    }
+
+}
+
+void QV4L2Camera::stopCapturing()
+{
+    if (!d)
+        return;
+
+    delete notifier;
+    notifier = nullptr;
+
+    enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+
+    if (ioctl(d->v4l2FileDescriptor, VIDIOC_STREAMOFF, &type) < 0) {
+        if (errno != ENODEV)
+            qWarning() << "failed to stop capture";
+    }
+    cameraBusy = false;
+}
+
+void QV4L2Camera::startCapturing()
+{
+    if (cameraBusy)
+        return;
+
+    // #### better to use the user data method instead of mmap???
+    qsizetype i;
+
+    for (i = 0; i < d->mappedBuffers.size(); ++i) {
+        v4l2_buffer buf = {};
+        buf.index = i;
+        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        buf.memory = V4L2_MEMORY_MMAP;
+
+        if (ioctl(d->v4l2FileDescriptor, VIDIOC_QBUF, &buf) < 0) {
+            qWarning() << "failed to set up mapped buffer";
+            return;
+        }
+    }
+    enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    if (ioctl(d->v4l2FileDescriptor, VIDIOC_STREAMON, &type) < 0)
+        qWarning() << "failed to start capture";
+
+    notifier = new QSocketNotifier(d->v4l2FileDescriptor, QSocketNotifier::Read);
+    connect(notifier, &QSocketNotifier::activated, this, &QV4L2Camera::readFrame);
+
+    firstFrameTime = { -1, -1 };
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/multimedia/v4l2/qv4l2camera_p.h b/src/plugins/multimedia/v4l2/qv4l2camera_p.h
new file mode 100644
index 000000000..714b4c1db
--- /dev/null
+++ b/src/plugins/multimedia/v4l2/qv4l2camera_p.h
@@ -0,0 +1,160 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QFFMPEGCAMERA_H
+#define QFFMPEGCAMERA_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qplatformcamera_p.h>
+#include <private/qplatformvideodevices_p.h>
+#include <private/qplatformmediaintegration_p.h>
+
+#include <qfilesystemwatcher.h>
+#include <qsocketnotifier.h>
+#include <qmutex.h>
+
+QT_BEGIN_NAMESPACE
+
+class QV4L2CameraDevices : public QObject,
+                           public QPlatformVideoDevices
+{
+    Q_OBJECT
+public:
+    QV4L2CameraDevices(QPlatformMediaIntegration *integration);
+
+    QList<QCameraDevice> videoDevices() const override;
+
+public Q_SLOTS:
+    void checkCameras();
+
+private:
+    void doCheckCameras();
+
+    QList<QCameraDevice> cameras;
+    QFileSystemWatcher deviceWatcher;
+};
+
+struct QV4L2CameraBuffers
+{
+public:
+    ~QV4L2CameraBuffers();
+
+    void release(int index);
+    void unmapBuffers();
+
+    QAtomicInt ref;
+    QMutex mutex;
+    struct MappedBuffer {
+        void *data;
+        qsizetype size;
+    };
+    QList<MappedBuffer> mappedBuffers;
+    int v4l2FileDescriptor = -1;
+};
+
+class Q_MULTIMEDIA_EXPORT QV4L2Camera : public QPlatformCamera
+{
+    Q_OBJECT
+
+public:
+    explicit QV4L2Camera(QCamera *parent);
+    ~QV4L2Camera();
+
+    bool isActive() const override;
+    void setActive(bool active) override;
+
+    void setCamera(const QCameraDevice &camera) override;
+    bool setCameraFormat(const QCameraFormat &format) override;
+    bool resolveCameraFormat(const QCameraFormat &format);
+
+    bool isFocusModeSupported(QCamera::FocusMode mode) const override;
+    void setFocusMode(QCamera::FocusMode /*mode*/) override;
+
+//    void setCustomFocusPoint(const QPointF &/*point*/) override;
+    void setFocusDistance(float) override;
+    void zoomTo(float /*newZoomFactor*/, float /*rate*/ = -1.) override;
+
+    void setFlashMode(QCamera::FlashMode /*mode*/) override;
+    bool isFlashModeSupported(QCamera::FlashMode mode) const override;
+    bool isFlashReady() const override;
+
+    void setTorchMode(QCamera::TorchMode /*mode*/) override;
+    bool isTorchModeSupported(QCamera::TorchMode mode) const override;
+
+    void setExposureMode(QCamera::ExposureMode) override;
+    bool isExposureModeSupported(QCamera::ExposureMode mode) const override;
+    void setExposureCompensation(float) override;
+    int isoSensitivity() const override;
+    void setManualIsoSensitivity(int) override;
+    void setManualExposureTime(float) override;
+    float exposureTime() const override;
+
+    bool isWhiteBalanceModeSupported(QCamera::WhiteBalanceMode mode) const override;
+    void setWhiteBalanceMode(QCamera::WhiteBalanceMode /*mode*/) override;
+    void setColorTemperature(int /*temperature*/) override;
+
+    void releaseBuffer(int index);
+
+private Q_SLOTS:
+    void readFrame();
+
+private:
+    void setCameraBusy();
+
+    bool m_active = false;
+
+    QCameraDevice m_cameraDevice;
+
+    void initV4L2Controls();
+    void closeV4L2Fd();
+    int setV4L2ColorTemperature(int temperature);
+    bool setV4L2Parameter(quint32 id, qint32 value);
+    int getV4L2Parameter(quint32 id) const;
+
+    void setV4L2CameraFormat();
+    void initMMap();
+    void startCapturing();
+    void stopCapturing();
+
+    QSocketNotifier *notifier = nullptr;
+    QExplicitlySharedDataPointer<QV4L2CameraBuffers> d;
+
+    bool v4l2AutoWhiteBalanceSupported = false;
+    bool v4l2ColorTemperatureSupported = false;
+    bool v4l2AutoExposureSupported = false;
+    bool v4l2ManualExposureSupported = false;
+    qint32 v4l2MinColorTemp = 5600; // Daylight...
+    qint32 v4l2MaxColorTemp = 5600;
+    qint32 v4l2MinExposure = 0;
+    qint32 v4l2MaxExposure = 0;
+    qint32 v4l2MinExposureAdjustment = 0;
+    qint32 v4l2MaxExposureAdjustment = 0;
+    qint32 v4l2MinFocus = 0;
+    qint32 v4l2MaxFocus = 0;
+    qint32 v4l2RangedFocus = false;
+    bool v4l2FlashSupported = false;
+    bool v4l2TorchSupported = false;
+    int v4l2MinZoom = 0;
+    int v4l2MaxZoom = 0;
+    timeval firstFrameTime = {-1, -1};
+    int bytesPerLine = -1;
+    QVideoFrameFormat::ColorSpace colorSpace = QVideoFrameFormat::ColorSpace_Undefined;
+    qint64 frameDuration = -1;
+    bool cameraBusy = false;
+};
+
+QT_END_NAMESPACE
+
+
+#endif  // QFFMPEGCAMERA_H
+