What is the most efficient way to display decoded video frames in Qt?

Question

What is the fastest way to display images to a Qt widget? I have decoded the video using libavformat and libavcodec, so I already have raw RGB or YCbCr 4:2:0 frames. I am

Answer 1

Depending on your OpenGL/shading skills you could try to copy the videos frames to a texture, map the texture to a rectangle (or anything else..fun!) and display it in a OpenGL scene. Not the most straight approach, but fast, because you're writing directly into the graphics memory (like SDL). I would also recoomend to use YCbCR only since this format is compressed (color, Y=full Cb,Cr are 1/4 of the frame) so less memory + less copying is needed to display a frame. I'm not using Qts GL directly but indirectly using GL in Qt (vis OSG) and can display about 7-11 full HD (1440 x 1080) videos in realtime.