[Interest] (code) Cannot map videoforames for QAbstractVideoSurface::present

[Igor Mironchik]

Hi,

Start from here:

bool
Frames::present( const QVideoFrame & frame )
{
   if( !isActive() )
     return false;

   QVideoFrame f = frame;
   f.map( QAbstractVideoBuffer::ReadOnly );

   QImage image( f.bits(), f.width(), f.height(), f.bytesPerLine(),
     QVideoFrame::imageFormatFromPixelFormat( f.pixelFormat() ) );

   f.unmap();

   emit newFrame( image.copy( image.rect() ) );

   return true;
}

This works for me...


14-Jun-18 17:52, Jason H пишет:
> I have no idea what I'm doing wrong. Can someone this and let me know?
> The frames I'm getting are BGR32, so I have special code for that.
> But I'm getting the message "QVideoFrame::unmap() was called more times then QVideoFrame::map()"
> Which is obviously not the case.
>
> To restate the problems:
> 1. I only get to present() once
> 2. I's failing to map frames
> 3. "then" in the message should be "than"
>
> Here's the first 3 lines of the .pro and complete code:
> extractframes.pro-----
> QT += multimedia
> CONFIG += c++11 console
> CONFIG -= app_bundle
>
> main.cpp--------------
> #include <QAbstractVideoSurface>
> #include <QGuiApplication>
> #include <QMediaPlayer>
> #include <QVideoSurfaceFormat>
>
> #include <QtDebug>
>
> class VideoSurface: public QAbstractVideoSurface {
> 		int _frameNumber;
> 		QVideoSurfaceFormat _format;
> 		QString _prefix;
> 		int _frameInterval;
> public:
> 		VideoSurface(const QString &prefix, int frameInterval): _prefix(prefix), _frameInterval(frameInterval) {	}
>
> 	bool present(const QVideoFrame &frame) override {
> 		qDebug() << Q_FUNC_INFO << _frameNumber << frame.isValid();
>
> 		if (_frameNumber % _frameInterval == 0) {
> 			QVideoFrame frame2(frame);
> 			frame2.map(QAbstractVideoBuffer::ReadOnly);
> 			QImage image;
>
> 			if (frame2.pixelFormat() == QVideoFrame::Format_BGR32) {
> 				 image =  QImage(frame2.bits(), frame2.width(), frame2.height(), QImage::Format_RGB32);
> 				 image = image.rgbSwapped();
> 			} else {
> 				image =  QImage(frame2.bits(), frame2.width(), frame2.height(), QVideoFrame::imageFormatFromPixelFormat(frame2.pixelFormat()));
> 			}
>
> 			frame2.unmap();
> 			QString filename = QString(_prefix).arg(_frameNumber);
> 			bool result = image.save(filename);
> 			qDebug() << Q_FUNC_INFO << filename << result;
> 		}
> 		_frameNumber ++;
> 		return true;
> 	}
>
> 	bool start(const QVideoSurfaceFormat &format) override {
> 		qDebug() << Q_FUNC_INFO;
> 		_format = format;
> 		_frameNumber = 0;
> 		QAbstractVideoSurface::start(format);
> 		return true;
> 	}
> 	void stop() override {
> 		qDebug() << Q_FUNC_INFO;
> 		QAbstractVideoSurface::stop();
> 	}
> 	QList<QVideoFrame::PixelFormat> supportedPixelFormats(QAbstractVideoBuffer::HandleType handleType) const override
> 	{
> 		Q_UNUSED(handleType);
> 		return QList<QVideoFrame::PixelFormat>()
> 			<< QVideoFrame::Format_ARGB32
> 			<< QVideoFrame::Format_ARGB32_Premultiplied
> 			<< QVideoFrame::Format_RGB32
> 			<< QVideoFrame::Format_RGB24
> 			<< QVideoFrame::Format_RGB565
> 			<< QVideoFrame::Format_RGB555
> 			<< QVideoFrame::Format_ARGB8565_Premultiplied
> 			<< QVideoFrame::Format_BGRA32
> 			<< QVideoFrame::Format_BGRA32_Premultiplied
> 			<< QVideoFrame::Format_BGR32
> 			<< QVideoFrame::Format_BGR24
> 			<< QVideoFrame::Format_BGR565
> 			<< QVideoFrame::Format_BGR555
> 			<< QVideoFrame::Format_BGRA5658_Premultiplied
> 			<< QVideoFrame::Format_AYUV444
> 			<< QVideoFrame::Format_AYUV444_Premultiplied
> 			<< QVideoFrame::Format_YUV444
> 			<< QVideoFrame::Format_YUV420P
> 			<< QVideoFrame::Format_YV12
> 			<< QVideoFrame::Format_UYVY
> 			<< QVideoFrame::Format_YUYV
> 			<< QVideoFrame::Format_NV12
> 			<< QVideoFrame::Format_NV21
> 			<< QVideoFrame::Format_IMC1
> 			<< QVideoFrame::Format_IMC2
> 			<< QVideoFrame::Format_IMC3
> 			<< QVideoFrame::Format_IMC4
> 			<< QVideoFrame::Format_Y8
> 			<< QVideoFrame::Format_Y16
> 			<< QVideoFrame::Format_Jpeg
> 			<< QVideoFrame::Format_CameraRaw
> 			<< QVideoFrame::Format_AdobeDng;
> 	}
>
>
> };
>
> // Command line: extractframes format interval
> // format:QString, with %1 = frame number
> // Example:
> // extractframes filename.mp4 image_%1.png 30
>
> int main(int argc, char *argv[])
> {
> 	QGuiApplication a(argc, argv);
> 	QMediaPlayer player;
> 	VideoSurface surface(argv[2], QString(argv[3]).toInt());
> 	QObject::connect(&player, &QMediaPlayer::mediaStatusChanged, [=]( QMediaPlayer::MediaStatus status ) {
> 		qDebug() << Q_FUNC_INFO << status;
> 	});
> 	QObject::connect(&player, QOverload<QMediaPlayer::Error>::of(&QMediaPlayer::error), [=]( QMediaPlayer::Error error ) {
> 		qDebug() << Q_FUNC_INFO << error;
> 	});
> 	QObject::connect(&player, &QMediaPlayer::stateChanged, [=]( const QMediaPlayer::State &state ) {
> 		qDebug() << Q_FUNC_INFO << state;
> 		if (QMediaPlayer::StoppedState == state) qApp->quit();
> 	});
>
> 	player.setMedia(QUrl::fromLocalFile(argv[1]));
> 	player.setVideoOutput(&surface);
> 	player.setMuted(true);
>
> 	player.play();
>
> 	return a.exec();
> }
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