High performance QImage output to display
c++, qimage, qpixmap, qt
Solution
Yes, render the frames to a `QGLWidget` and let the video card handle it. That's how Qt MultimediaKit, Phonon and others do it.
Some time ago I shared some code that demonstrated how to accomplish this task: Image scaling (KeepAspectRatioByExpanding) through OpenGL
Problem
I'm trying to make video output (sequence of frames) to any qt visible widget. At beginning i thought that QLabel will be enough for this point... but i was wrong. Converting to pixmap is too overloading for processor at large images: 1080p for example. Any other solution? (not QLabel?) Example of code for one frame: ``` QImage m_outputFrameImage(width, height, QImage::Format_RGB888); memcpy(m_outputFrameImage.bits(), m_frameRGB->data[0], height * width * 3); QPixmap pixmap = QPixmap::fromImage(m_outputFrameImage); // BAD, slow and high load /* Bad too (Same code?) QPainter painter; painter.begin(&pixmap); painter.drawImage(0, 0, m_outputFrameImage); painter.end(); */ labelVideo->setPixmap(pixmap); ```