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/*
SPDX-FileCopyrightText: 2006-2008 Marco Gulino <marco@kmobiletools.org>
SPDX-FileCopyrightText: Jean-Baptiste Mardelle <jb@kdenlive.org>
SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
*/
#include "mltpreview.h"
#include "../src/lib/localeHandling.h"
#include <QDebug>
#include <QImage>
#include <QVarLengthArray>
#include <QtGlobal>
#include <KPluginFactory>
K_PLUGIN_CLASS_WITH_JSON(MltPreview, "mltpreview.json")
MltPreview::MltPreview(QObject *parent, const QVariantList &args)
: KIO::ThumbnailCreator(parent, args)
{
// block MLT Qt5 modules to prevent crashes
qputenv("MLT_REPOSITORY_DENY", "libmltqt:libmltglaxnimate");
// After initialising the MLT factory, set the locale back from user default to C
// to ensure numbers are always serialised with . as decimal point.
Mlt::Factory::init();
LocaleHandling::resetLocale();
}
MltPreview::~MltPreview()
{
Mlt::Factory::close();
}
KIO::ThumbnailResult MltPreview::create(const KIO::ThumbnailRequest &request)
{
int width = request.targetSize().width();
int height = request.targetSize().height();
std::unique_ptr<Mlt::Profile> profile(new Mlt::Profile());
std::shared_ptr<Mlt::Producer> producer(new Mlt::Producer(*profile.get(), "xml-nogl", request.url().toLocalFile().toUtf8().data()));
if (producer == nullptr || !producer->is_valid() || producer->is_blank()) {
return KIO::ThumbnailResult::fail();
}
uint variance = 10;
int ct = 1;
double ar = profile->dar();
if (ar < 1e-6) {
ar = 1.0;
}
int wanted_width = width;
int wanted_height = int(width / ar);
if (wanted_height > height) {
wanted_height = height;
wanted_width = int(height * ar);
}
// We don't need audio
producer->set("audio_index", -1);
// Add normalizers
Mlt::Filter scaler(*profile.get(), "swscale");
Mlt::Filter padder(*profile.get(), "resize");
Mlt::Filter converter(*profile.get(), "avcolor_space");
if (scaler.is_valid()) {
producer->attach(scaler);
}
if (padder.is_valid()) {
producer->attach(padder);
}
if (converter.is_valid()) {
producer->attach(converter);
}
QImage img;
int length = producer->get_length();
if (length < 1) {
return KIO::ThumbnailResult::fail();
}
int frame = qMin(75, length - 1);
while (variance <= 40 && ct < 4 && frame < length) {
img = getFrame(producer, frame, wanted_width, wanted_height);
variance = uint(imageVariance(img));
frame += 100 * ct;
ct++;
}
if (img.isNull()) {
return KIO::ThumbnailResult::fail();
}
return KIO::ThumbnailResult::pass(img);
}
QImage MltPreview::getFrame(std::shared_ptr<Mlt::Producer> producer, int framepos, int width, int height)
{
QImage mltImage(width, height, QImage::Format_ARGB32);
if (producer == nullptr) {
return mltImage;
}
producer->seek(framepos);
std::shared_ptr<Mlt::Frame> frame(producer->get_frame());
if (frame == nullptr || !frame->is_valid()) {
return mltImage;
}
mlt_image_format format = mlt_image_rgba;
const uchar *imagedata = frame->get_image(format, width, height);
if (imagedata != nullptr) {
memcpy(mltImage.bits(), imagedata, size_t(width * height * 4));
mltImage = mltImage.rgbSwapped();
}
return mltImage;
}
int MltPreview::imageVariance(const QImage &image)
{
if (image.isNull()) {
return 0;
}
int delta = 0;
int avg = 0;
int bytes = int(image.sizeInBytes());
int STEPS = bytes / 2;
if (STEPS < 1) {
return 0;
}
QVarLengthArray<uchar> pivot(STEPS);
// qDebug() << "Using " << STEPS << " steps\n";
const uchar *bits = image.bits();
// First pass: get pivots and taking average
for (int i = 0; i < STEPS; i++) {
pivot[i] = bits[2 * i];
avg += pivot.at(i);
}
avg = avg / STEPS;
// Second Step: calculate delta (average?)
for (int i = 0; i < STEPS; ++i) {
int curdelta = abs(avg - pivot.at(i));
delta += curdelta;
}
return delta / STEPS;
}
#include "mltpreview.moc"
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