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Improve performance of rgb(a) reading, convert directly to greyscale

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This again leads to a noticeable performance improvement of the
QZXingFilter example, as we get rid of one full copy of the image
data by converting directly into greyscale, instead of first
converting to RGB and then converting to greyscale.
This commit is contained in:
Milian Wolff 2016-12-19 17:40:39 +01:00
parent 9d378fa2e4
commit c882465649
2 changed files with 47 additions and 39 deletions
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84
examples/QZXingLive/QZXingFilter.cpp
View File

@ -59,32 +59,6 @@ QVideoFilterRunnable * QZXingFilter::createFilterRunnable()
return new QZXingFilterRunnable(this);
}
/// Qt cant natively create a QImage from certain PixelFormats (BGR and YUV).
/// As Android QVideoFrames are encoded as BGR, we created this conversion function.
QImage QZXingFilter::fromBGRAtoARGB(const uchar * data, QSize size, QVideoFrame::PixelFormat pixelFormat)
{
if(pixelFormat != QVideoFrame::Format_BGRA32
&& pixelFormat != QVideoFrame::Format_BGRA32_Premultiplied
&& pixelFormat != QVideoFrame::Format_BGR32)
{
return QImage();
}
QImage image(size.width(), size.height(), QImage::Format_Grayscale8);
uchar* out = image.bits();
const int bits = size.width() * size.height();
for (int i = 0; i < bits; ++i)
{
*out = gray(data[2], data[1], data[0]);
// alpha is ignored
data += 4;
++out;
}
return image;
}
///
/// QZXingFilterRunnable
///
@ -131,6 +105,31 @@ QVideoFrame QZXingFilterRunnable::run(QVideoFrame * input, const QVideoSurfaceFo
return * input;
}
static QImage rgbDataToGrayscale(const uchar* data, const int width, const int height,
const int alpha, const int red,
const int green, const int blue,
const bool isPremultiplied = false)
{
QImage image(width, height, QImage::Format_Grayscale8);
uchar* pixel = image.bits();
uchar* const pixelEnd = pixel + (width * height);
const int stride = (alpha < 0) ? 3 : 4;
for (; pixel != pixelEnd; ++pixel, data += stride) {
uchar r = data[red];
uchar g = data[green];
uchar b = data[blue];
if (isPremultiplied) {
uchar a = data[alpha];
r = (uint(r) * 255) / a;
g = (uint(g) * 255) / a;
b = (uint(b) * 255) / a;
}
*pixel = gray(r, g, b);
}
return image;
}
void QZXingFilterRunnable::processVideoFrameProbed(SimpleVideoFrame & videoFrame, const QRect& captureRect)
{
static unsigned int i = 0; i++;
@ -140,13 +139,23 @@ void QZXingFilterRunnable::processVideoFrameProbed(SimpleVideoFrame & videoFrame
const int height = videoFrame.size.height();
const uchar* data = (uchar*) videoFrame.data.constData();
/// Create QImage from QVideoFrame.
QImage::Format imageFormat = QVideoFrame::imageFormatFromPixelFormat(videoFrame.pixelFormat);
QImage image(data, width, height, imageFormat);
QImage image;
/// If it fails, it's probably a format problem.
/// Let's try to convert it from BGR formats to RGB
if(image.isNull())
image = QZXingFilter::fromBGRAtoARGB(data, videoFrame.size, videoFrame.pixelFormat);
/// Let's try to convert it from RGB formats
if (videoFrame.pixelFormat == QVideoFrame::Format_RGB32)
image = rgbDataToGrayscale(data, width, height, -1, 1, 2, 3);
else if (videoFrame.pixelFormat == QVideoFrame::Format_ARGB32)
image = rgbDataToGrayscale(data, width, height, 0, 1, 2, 3);
else if (videoFrame.pixelFormat == QVideoFrame::Format_ARGB32_Premultiplied)
image = rgbDataToGrayscale(data, width, height, 0, 1, 2, 3, true);
else if (videoFrame.pixelFormat == QVideoFrame::Format_BGRA32)
image = rgbDataToGrayscale(data, width, height, 3, 2, 1, 0);
else if (videoFrame.pixelFormat == QVideoFrame::Format_BGRA32_Premultiplied)
image = rgbDataToGrayscale(data, width, height, 3, 2, 1, 0, true);
else if (videoFrame.pixelFormat == QVideoFrame::Format_BGR32)
image = rgbDataToGrayscale(data, width, height, 3, 2, 1, 0);
else if (videoFrame.pixelFormat == QVideoFrame::Format_BGR24)
image = rgbDataToGrayscale(data, width, height, -1, 2, 1, 0);
/// This is a forced "conversion", colors end up swapped.
if(image.isNull() && videoFrame.pixelFormat == QVideoFrame::Format_BGR555)
@ -156,10 +165,6 @@ void QZXingFilterRunnable::processVideoFrameProbed(SimpleVideoFrame & videoFrame
if(image.isNull() && videoFrame.pixelFormat == QVideoFrame::Format_BGR565)
image = QImage(data, width, height, QImage::Format_RGB16);
/// This is a forced "conversion", colors end up swapped.
if(image.isNull() && videoFrame.pixelFormat == QVideoFrame::Format_BGR24)
image = QImage(data, width, height, QImage::Format_RGB888);
//fix for issues #4 and #9
if(image.isNull() && videoFrame.pixelFormat == QVideoFrame::Format_YUV420P) {
image = QImage(videoFrame.size, QImage::Format_Grayscale8);
@ -205,12 +210,17 @@ void QZXingFilterRunnable::processVideoFrameProbed(SimpleVideoFrame & videoFrame
/// TODO: Handle (create QImages from) YUV formats.
if (image.isNull()) {
QImage::Format imageFormat = QVideoFrame::imageFormatFromPixelFormat(videoFrame.pixelFormat);
image = QImage(data, width, height, imageFormat);
}
if(image.isNull())
{
qDebug() << "QZXingFilterRunnable error: Cant create image file to process.";
qDebug() << "Maybe it was a format conversion problem? ";
qDebug() << "VideoFrame format: " << videoFrame.pixelFormat;
qDebug() << "Image corresponding format: " << imageFormat;
qDebug() << "Image corresponding format: " << QVideoFrame::imageFormatFromPixelFormat(videoFrame.pixelFormat);
filter->decoding = false;
return;
}

2
examples/QZXingLive/QZXingFilter.h
View File

@ -88,8 +88,6 @@ class QZXingFilter : public QAbstractVideoFilter
QZXing* getDecoder() { return &decoder; }
QVideoFilterRunnable * createFilterRunnable();
static QImage fromBGRAtoARGB(const uchar * data, QSize size, QVideoFrame::PixelFormat pixelFormat);
};
/// A new Runnable is created everytime the filter gets a new frame