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Player example histogram: Process frames on a separate thread

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Change-Id: I6989f9ea9cb6e45c54ed75079a5b5748e15ee0d8
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>
This commit is contained in:
Lev Zelenskiy
2012-07-19 14:55:52 +10:00
committed by Qt by Nokia
parent b7f4b2decb
commit b915c5e0e7
2 changed files with 93 additions and 50 deletions
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127
examples/player/histogramwidget.cpp
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@@ -44,63 +44,34 @@
HistogramWidget::HistogramWidget(QWidget *parent)
: QWidget(parent)
, m_levels(128)
, m_isBusy(false)
{
m_processor.moveToThread(&m_processorThread);
qRegisterMetaType<QVector<qreal> >("QVector<qreal>");
connect(&m_processor, SIGNAL(histogramReady(QVector<qreal>)), SLOT(setHistogram(QVector<qreal>)));
m_processorThread.start(QThread::LowestPriority);
}
HistogramWidget::~HistogramWidget()
{
m_processorThread.quit();
m_processorThread.wait(10000);
}
void HistogramWidget::processFrame(QVideoFrame frame)
{
m_histogram.clear();
if (m_isBusy)
return; //drop frame
do {
if (!m_levels)
break;
if (!frame.map(QAbstractVideoBuffer::ReadOnly))
break;
m_histogram.resize(m_levels);
if (frame.pixelFormat() == QVideoFrame::Format_YUV420P) {
// Process YUV420P data
uchar *b = frame.bits();
for (int y = 0; y < frame.height(); y++) {
uchar *lastPixel = b + frame.width();
for (uchar *curPixel = b; curPixel < lastPixel; curPixel++)
m_histogram[(*curPixel * m_levels) / 256] += 1.0;
b += frame.bytesPerLine();
}
} else {
QImage::Format imageFormat = QVideoFrame::imageFormatFromPixelFormat(frame.pixelFormat());
if (imageFormat != QImage::Format_Invalid) {
// Process RGB data
QImage image(frame.bits(), frame.width(), frame.height(), imageFormat);
image = image.convertToFormat(QImage::Format_RGB32);
const QRgb* b = (const QRgb*)image.bits();
for (int y = 0; y < image.height(); y++) {
const QRgb *lastPixel = b + frame.width();
for (const QRgb *curPixel = b; curPixel < lastPixel; curPixel++)
m_histogram[(qGray(*curPixel) * m_levels) / 256] += 1.0;
b = (const QRgb*)((uchar*)b + image.bytesPerLine());
}
}
}
// find maximum value
qreal maxValue = 0.0;
for (int i = 0; i < m_histogram.size(); i++) {
if (m_histogram[i] > maxValue)
maxValue = m_histogram[i];
}
if (maxValue > 0.0) {
for (int i = 0; i < m_histogram.size(); i++)
m_histogram[i] /= maxValue;
}
frame.unmap();
} while (false);
m_isBusy = true;
QMetaObject::invokeMethod(&m_processor, "processFrame",
Qt::QueuedConnection, Q_ARG(QVideoFrame, frame), Q_ARG(int, m_levels));
}
void HistogramWidget::setHistogram(QVector<qreal> histogram)
{
m_isBusy = false;
m_histogram = histogram;
update();
}
@@ -125,3 +96,59 @@ void HistogramWidget::paintEvent(QPaintEvent *event)
painter.fillRect(barWidth * i, 0, barWidth * (i + 1), height() - h, Qt::black);
}
}
void FrameProcessor::processFrame(QVideoFrame frame, int levels)
{
QVector<qreal> histogram(levels);
do {
if (!levels)
break;
if (!frame.map(QAbstractVideoBuffer::ReadOnly))
break;
if (frame.pixelFormat() == QVideoFrame::Format_YUV420P ||
frame.pixelFormat() == QVideoFrame::Format_NV12) {
// Process YUV data
uchar *b = frame.bits();
for (int y = 0; y < frame.height(); y++) {
uchar *lastPixel = b + frame.width();
for (uchar *curPixel = b; curPixel < lastPixel; curPixel++)
histogram[(*curPixel * levels) >> 8] += 1.0;
b += frame.bytesPerLine();
}
} else {
QImage::Format imageFormat = QVideoFrame::imageFormatFromPixelFormat(frame.pixelFormat());
if (imageFormat != QImage::Format_Invalid) {
// Process RGB data
QImage image(frame.bits(), frame.width(), frame.height(), imageFormat);
image = image.convertToFormat(QImage::Format_RGB32);
const QRgb* b = (const QRgb*)image.bits();
for (int y = 0; y < image.height(); y++) {
const QRgb *lastPixel = b + frame.width();
for (const QRgb *curPixel = b; curPixel < lastPixel; curPixel++)
histogram[(qGray(*curPixel) * levels) >> 8] += 1.0;
b = (const QRgb*)((uchar*)b + image.bytesPerLine());
}
}
}
// find maximum value
qreal maxValue = 0.0;
for (int i = 0; i < histogram.size(); i++) {
if (histogram[i] > maxValue)
maxValue = histogram[i];
}
if (maxValue > 0.0) {
for (int i = 0; i < histogram.size(); i++)
histogram[i] /= maxValue;
}
frame.unmap();
} while (false);
emit histogramReady(histogram);
}