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#include "qgstreamervideoencode.h"
#include "qgstreamercapturesession.h"
#include "qgstreamermediacontainercontrol.h"
#include <private/qgstutils_p.h>
#include <QtCore/qdebug.h>

#include <math.h>

QGstreamerVideoEncode::QGstreamerVideoEncode(QGstreamerCaptureSession *session)
    :QVideoEncoderSettingsControl(session), m_session(session)
    , m_codecs(QGstCodecsInfo::VideoEncoder)
{
    for (const QString& codecName : supportedVideoCodecs()) {
        GstElementFactory *factory = gst_element_factory_find(m_codecs.codecElement(codecName).constData());
        if (factory) {
            m_streamTypes.insert(codecName,
                                 QGstreamerMediaContainerControl::supportedStreamTypes(factory, GST_PAD_SRC));

            gst_object_unref(GST_OBJECT(factory));
        }
    }
}

QGstreamerVideoEncode::~QGstreamerVideoEncode()
{
}

QList<QSize> QGstreamerVideoEncode::supportedResolutions(const QVideoEncoderSettings &, bool *continuous) const
{
    if (continuous)
        *continuous = m_session->videoInput() != 0;

    return m_session->videoInput() ? m_session->videoInput()->supportedResolutions() : QList<QSize>();
}

QList< qreal > QGstreamerVideoEncode::supportedFrameRates(const QVideoEncoderSettings &, bool *continuous) const
{
    if (continuous)
        *continuous = false;

    return m_session->videoInput() ? m_session->videoInput()->supportedFrameRates() : QList<qreal>();
}

QStringList QGstreamerVideoEncode::supportedVideoCodecs() const
{
    return m_codecs.supportedCodecs();
}

QString QGstreamerVideoEncode::videoCodecDescription(const QString &codecName) const
{
    return m_codecs.codecDescription(codecName);
}

QStringList QGstreamerVideoEncode::supportedEncodingOptions(const QString &codec) const
{
    return m_codecs.codecOptions(codec);
}

QVariant QGstreamerVideoEncode::encodingOption(const QString &codec, const QString &name) const
{
    return m_options[codec].value(name);
}

void QGstreamerVideoEncode::setEncodingOption(
        const QString &codec, const QString &name, const QVariant &value)
{
    m_options[codec][name] = value;
}

QVideoEncoderSettings QGstreamerVideoEncode::videoSettings() const
{
    return m_videoSettings;
}

void QGstreamerVideoEncode::setVideoSettings(const QVideoEncoderSettings &settings)
{
    m_videoSettings = settings;
}

GstElement *QGstreamerVideoEncode::createEncoder()
{
    QString codec = m_videoSettings.codec();
    GstElement *encoderElement = gst_element_factory_make(m_codecs.codecElement(codec).constData(), "video-encoder");
    if (!encoderElement)
        return 0;

    GstBin *encoderBin = GST_BIN(gst_bin_new("video-encoder-bin"));

    GstElement *sinkCapsFilter = gst_element_factory_make("capsfilter", "capsfilter-video");
    GstElement *srcCapsFilter = gst_element_factory_make("capsfilter", "capsfilter-video");
    gst_bin_add_many(encoderBin, sinkCapsFilter, srcCapsFilter, NULL);

    GstElement *colorspace = gst_element_factory_make(QT_GSTREAMER_COLORCONVERSION_ELEMENT_NAME, NULL);
    gst_bin_add(encoderBin, colorspace);
    gst_bin_add(encoderBin, encoderElement);

    gst_element_link_many(sinkCapsFilter, colorspace, encoderElement, srcCapsFilter, NULL);

    // add ghostpads
    GstPad *pad = gst_element_get_static_pad(sinkCapsFilter, "sink");
    gst_element_add_pad(GST_ELEMENT(encoderBin), gst_ghost_pad_new("sink", pad));
    gst_object_unref(GST_OBJECT(pad));

    pad = gst_element_get_static_pad(srcCapsFilter, "src");
    gst_element_add_pad(GST_ELEMENT(encoderBin), gst_ghost_pad_new("src", pad));
    gst_object_unref(GST_OBJECT(pad));

    if (encoderElement) {
        if (m_videoSettings.encodingMode() == QMultimedia::ConstantQualityEncoding) {
            QMultimedia::EncodingQuality qualityValue = m_videoSettings.quality();

            if (codec == QLatin1String("video/x-h264")) {
                //constant quantizer mode
                g_object_set(G_OBJECT(encoderElement), "pass", 4, NULL);
                int qualityTable[] = {
                    50, //VeryLow
                    35, //Low
                    21, //Normal
                    15, //High
                    8 //VeryHigh
                };
                g_object_set(G_OBJECT(encoderElement), "quantizer", qualityTable[qualityValue], NULL);
            } else if (codec == QLatin1String("video/x-xvid")) {
                //constant quantizer mode
                g_object_set(G_OBJECT(encoderElement), "pass", 3, NULL);
                int qualityTable[] = {
                    32, //VeryLow
                    12, //Low
                    5, //Normal
                    3, //High
                    2 //VeryHigh
                };
                int quant = qualityTable[qualityValue];
                g_object_set(G_OBJECT(encoderElement), "quantizer", quant, NULL);
            } else if (codec.startsWith(QLatin1String("video/mpeg"))) {
                //constant quantizer mode
                g_object_set(G_OBJECT(encoderElement), "pass", 2, NULL);
                //quant from 1 to 30, default ~3
                double qualityTable[] = {
                    20, //VeryLow
                    8.0, //Low
                    3.0, //Normal
                    2.5, //High
                    2.0 //VeryHigh
                };
                double quant = qualityTable[qualityValue];
                g_object_set(G_OBJECT(encoderElement), "quantizer", quant, NULL);
            } else if (codec == QLatin1String("video/x-theora")) {
                int qualityTable[] = {
                    8, //VeryLow
                    16, //Low
                    32, //Normal
                    45, //High
                    60 //VeryHigh
                };
                //quality from 0 to 63
                int quality = qualityTable[qualityValue];
                g_object_set(G_OBJECT(encoderElement), "quality", quality, NULL);
            }
        } else {
            int bitrate = m_videoSettings.bitRate();
            if (bitrate > 0) {
                g_object_set(G_OBJECT(encoderElement), "bitrate", bitrate, NULL);
            }
        }

        QMap<QString,QVariant> options = m_options.value(codec);
        QMapIterator<QString,QVariant> it(options);
        while (it.hasNext()) {
            it.next();
            QString option = it.key();
            QVariant value = it.value();

            switch (value.type()) {
            case QVariant::Int:
                g_object_set(G_OBJECT(encoderElement), option.toLatin1(), value.toInt(), NULL);
                break;
            case QVariant::Bool:
                g_object_set(G_OBJECT(encoderElement), option.toLatin1(), value.toBool(), NULL);
                break;
            case QVariant::Double:
                g_object_set(G_OBJECT(encoderElement), option.toLatin1(), value.toDouble(), NULL);
                break;
            case QVariant::String:
                g_object_set(G_OBJECT(encoderElement), option.toLatin1(), value.toString().toUtf8().constData(), NULL);
                break;
            default:
                qWarning() << "unsupported option type:" << option << value;
                break;
            }

        }
    }

    if (!m_videoSettings.resolution().isEmpty() || m_videoSettings.frameRate() > 0.001) {
        GstCaps *caps = QGstUtils::videoFilterCaps();

        if (!m_videoSettings.resolution().isEmpty()) {
            gst_caps_set_simple(
                        caps,
                        "width", G_TYPE_INT, m_videoSettings.resolution().width(),
                        "height", G_TYPE_INT, m_videoSettings.resolution().height(),
                        NULL);
        }

        if (m_videoSettings.frameRate() > 0.001) {
            QPair<int,int> rate = rateAsRational();
            gst_caps_set_simple(
                        caps,
                        "framerate", GST_TYPE_FRACTION, rate.first, rate.second,
                        NULL);
        }

        //qDebug() << "set video caps filter:" << gst_caps_to_string(caps);

        g_object_set(G_OBJECT(sinkCapsFilter), "caps", caps, NULL);

        gst_caps_unref(caps);
    }

    // Some encoders support several codecs. Setting a caps filter downstream with the desired
    // codec (which is actually a string representation of the caps) will make sure we use the
    // correct codec.
    GstCaps *caps = gst_caps_from_string(codec.toUtf8().constData());
    g_object_set(G_OBJECT(srcCapsFilter), "caps", caps, NULL);
    gst_caps_unref(caps);

    return GST_ELEMENT(encoderBin);
}

QPair<int,int> QGstreamerVideoEncode::rateAsRational() const
{
    qreal frameRate = m_videoSettings.frameRate();

    if (frameRate > 0.001) {
        //convert to rational number
        QList<int> denumCandidates;
        denumCandidates << 1 << 2 << 3 << 5 << 10 << 1001 << 1000;

        qreal error = 1.0;
        int num = 1;
        int denum = 1;

        for (int curDenum : qAsConst(denumCandidates)) {
            int curNum = qRound(frameRate*curDenum);
            qreal curError = qAbs(qreal(curNum)/curDenum - frameRate);

            if (curError < error) {
                error = curError;
                num = curNum;
                denum = curDenum;
            }

            if (curError < 1e-8)
                break;
        }

        return QPair<int,int>(num,denum);
    }

    return QPair<int,int>();
}


QSet<QString> QGstreamerVideoEncode::supportedStreamTypes(const QString &codecName) const
{
    return m_streamTypes.value(codecName);
}