qgstreamerimagecapture.cpp

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// 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 "qgstreamerimagecapture_p.h"
#include <private/qplatformcamera_p.h>
#include <private/qplatformimagecapture_p.h>
#include <qgstvideobuffer_p.h>
#include <qgstutils_p.h>
#include <qgstreamermetadata_p.h>
#include <qvideoframeformat.h>
#include <private/qmediastoragelocation_p.h>
 
#include <QtCore/QDebug>
#include <QtCore/QDir>
#include <utility>
#include <qstandardpaths.h>
 
#include <qloggingcategory.h>
 
QT_BEGIN_NAMESPACE
 
static Q_LOGGING_CATEGORY(qLcImageCaptureGst, "qt.multimedia.imageCapture")
 
QMaybe<QPlatformImageCapture *> QGstreamerImageCapture::create(QImageCapture *parent)
{
    QGstElement videoconvert("videoconvert", "imageCaptureConvert");
    if (!videoconvert)
        return errorMessageCannotFindElement("videoconvert");
 
    QGstElement jpegenc("jpegenc", "jpegEncoder");
    if (!jpegenc)
        return errorMessageCannotFindElement("jpegenc");
 
    QGstElement jifmux("jifmux", "jpegMuxer");
    if (!jifmux)
        return errorMessageCannotFindElement("jifmux");
 
    return new QGstreamerImageCapture(videoconvert, jpegenc, jifmux, parent);
}
 
QGstreamerImageCapture::QGstreamerImageCapture(QGstElement videoconvert, QGstElement jpegenc,
                                               QGstElement jifmux, QImageCapture *parent)
    : QPlatformImageCapture(parent),
      QGstreamerBufferProbe(ProbeBuffers),
      videoConvert(std::move(videoconvert)),
      encoder(std::move(jpegenc)),
      muxer(std::move(jifmux))
{
    bin = QGstBin("imageCaptureBin");
 
    queue = QGstElement("queue", "imageCaptureQueue");
    // configures the queue to be fast, lightweight and non blocking
    queue.set("leaky", 2 /*downstream*/);
    queue.set("silent", true);
    queue.set("max-size-buffers", uint(1));
    queue.set("max-size-bytes", uint(0));
    queue.set("max-size-time", quint64(0));
 
    sink = QGstElement("fakesink","imageCaptureSink");
    filter = QGstElement("capsfilter", "filter");
    // imageCaptureSink do not wait for a preroll buffer when going READY -> PAUSED
    // as no buffer will arrive until capture() is called
    sink.set("async", false);
 
    bin.add(queue, filter, videoConvert, encoder, muxer, sink);
    queue.link(filter, videoConvert, encoder, muxer, sink);
    bin.addGhostPad(queue, "sink");
 
    addProbeToPad(queue.staticPad("src").pad(), false);
 
    sink.set("signal-handoffs", true);
    g_signal_connect(sink.object(), "handoff", G_CALLBACK(&QGstreamerImageCapture::saveImageFilter), this);
}
 
QGstreamerImageCapture::~QGstreamerImageCapture()
{
    bin.setStateSync(GST_STATE_NULL);
}
 
bool QGstreamerImageCapture::isReadyForCapture() const
{
    return m_session && !passImage && cameraActive;
}
 
int QGstreamerImageCapture::capture(const QString &fileName)
{
    QString path = QMediaStorageLocation::generateFileName(fileName, QStandardPaths::PicturesLocation, QLatin1String("jpg"));
    return doCapture(path);
}
 
int QGstreamerImageCapture::captureToBuffer()
{
    return doCapture(QString());
}
 
int QGstreamerImageCapture::doCapture(const QString &fileName)
{
    qCDebug(qLcImageCaptureGst) << "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(qLcImageCaptureGst) << "error 1";
        return -1;
    }
    if (!m_session->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(qLcImageCaptureGst) << "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(qLcImageCaptureGst) << "error 3";
        return -1;
    }
    m_lastId++;
 
    pendingImages.enqueue({m_lastId, fileName, QMediaMetaData{}});
    // let one image pass the pipeline
    passImage = true;
 
    emit readyForCaptureChanged(false);
    return m_lastId;
}
 
void QGstreamerImageCapture::setResolution(const QSize &resolution)
{
    auto padCaps = QGstCaps(gst_pad_get_current_caps(bin.staticPad("sink").pad()), QGstCaps::HasRef);
    if (padCaps.isNull()) {
        qDebug() << "Camera not ready";
        return;
    }
    auto caps = QGstCaps(gst_caps_copy(padCaps.get()), QGstCaps::HasRef);
    if (caps.isNull()) {
        return;
    }
    gst_caps_set_simple(caps.get(),
        "width", G_TYPE_INT, resolution.width(),
        "height", G_TYPE_INT, resolution.height(),
        nullptr);
    filter.set("caps", caps);
}
 
bool QGstreamerImageCapture::probeBuffer(GstBuffer *buffer)
{
    if (!passImage)
        return false;
    qCDebug(qLcImageCaptureGst) << "probe buffer";
 
    passImage = false;
 
    emit readyForCaptureChanged(isReadyForCapture());
 
    auto caps = QGstCaps(gst_pad_get_current_caps(bin.staticPad("sink").pad()), QGstCaps::HasRef);
    GstVideoInfo previewInfo;
    gst_video_info_from_caps(&previewInfo, caps.get());
 
    auto memoryFormat = caps.memoryFormat();
    auto fmt = caps.formatForCaps(&previewInfo);
    auto *sink = m_session->gstreamerVideoSink();
    auto *gstBuffer = new QGstVideoBuffer(buffer, previewInfo, sink, fmt, memoryFormat);
    QVideoFrame frame(gstBuffer, fmt);
    QImage img = frame.toImage();
    if (img.isNull()) {
        qDebug() << "received a null image";
        return true;
    }
 
    auto &imageData = pendingImages.head();
 
    emit imageExposed(imageData.id);
 
    qCDebug(qLcImageCaptureGst) << "Image available!";
    emit imageAvailable(imageData.id, frame);
 
    emit imageCaptured(imageData.id, img);
 
    QMediaMetaData metaData = this->metaData();
    metaData.insert(QMediaMetaData::Date, QDateTime::currentDateTime());
    metaData.insert(QMediaMetaData::Resolution, frame.size());
    imageData.metaData = metaData;
 
    // ensure taginject injects this metaData
    const auto &md = static_cast<const QGstreamerMetaData &>(metaData);
    md.setMetaData(muxer.element());
 
    emit imageMetadataAvailable(imageData.id, metaData);
 
    return true;
}
 
void QGstreamerImageCapture::setCaptureSession(QPlatformMediaCaptureSession *session)
{
    QGstreamerMediaCapture *captureSession = static_cast<QGstreamerMediaCapture *>(session);
    if (m_session == captureSession)
        return;
 
    bool readyForCapture = isReadyForCapture();
    if (m_session) {
        disconnect(m_session, nullptr, this, nullptr);
        m_lastId = 0;
        pendingImages.clear();
        passImage = false;
        cameraActive = false;
    }
 
    m_session = captureSession;
    if (!m_session) {
        if (readyForCapture)
            emit readyForCaptureChanged(false);
        return;
    }
 
    connect(m_session, &QPlatformMediaCaptureSession::cameraChanged, this, &QGstreamerImageCapture::onCameraChanged);
    onCameraChanged();
}
 
void QGstreamerImageCapture::cameraActiveChanged(bool active)
{
    qCDebug(qLcImageCaptureGst) << "cameraActiveChanged" << cameraActive << active;
    if (cameraActive == active)
        return;
    cameraActive = active;
    qCDebug(qLcImageCaptureGst) << "isReady" << isReadyForCapture();
    emit readyForCaptureChanged(isReadyForCapture());
}
 
void QGstreamerImageCapture::onCameraChanged()
{
    if (m_session->camera()) {
        cameraActiveChanged(m_session->camera()->isActive());
        connect(m_session->camera(), &QPlatformCamera::activeChanged, this, &QGstreamerImageCapture::cameraActiveChanged);
    } else {
        cameraActiveChanged(false);
    }
}
 
gboolean QGstreamerImageCapture::saveImageFilter(GstElement *element,
                                                       GstBuffer *buffer,
                                                       GstPad *pad,
                                                       void *appdata)
{
    Q_UNUSED(element);
    Q_UNUSED(pad);
    QGstreamerImageCapture *capture = static_cast<QGstreamerImageCapture *>(appdata);
 
    capture->passImage = false;
 
    if (capture->pendingImages.isEmpty()) {
        return true;
    }
 
    auto imageData = capture->pendingImages.dequeue();
    if (imageData.filename.isEmpty()) {
        return true;
    }
 
    qCDebug(qLcImageCaptureGst) << "saving image as" << imageData.filename;
 
    QFile f(imageData.filename);
    if (f.open(QFile::WriteOnly)) {
        GstMapInfo info;
        if (gst_buffer_map(buffer, &info, GST_MAP_READ)) {
            f.write(reinterpret_cast<const char *>(info.data), info.size);
            gst_buffer_unmap(buffer, &info);
        }
        f.close();
 
        static QMetaMethod savedSignal = QMetaMethod::fromSignal(&QGstreamerImageCapture::imageSaved);
        savedSignal.invoke(capture,
                           Qt::QueuedConnection,
                           Q_ARG(int, imageData.id),
                           Q_ARG(QString, imageData.filename));
    } else {
        qCDebug(qLcImageCaptureGst) << "   could not open image file for writing";
    }
 
    return TRUE;
}
 
QImageEncoderSettings QGstreamerImageCapture::imageSettings() const
{
    return m_settings;
}
 
void QGstreamerImageCapture::setImageSettings(const QImageEncoderSettings &settings)
{
    if (m_settings != settings) {
        QSize resolution = settings.resolution();
        if (m_settings.resolution() != resolution && !resolution.isEmpty()) {
            setResolution(resolution);
        }
        m_settings = settings;
    }
}
 
QT_END_NAMESPACE
 
#include "moc_qgstreamerimagecapture_p.cpp"