In my experience memory is very slow on the RPis... I'm talking factor if 10 improvements by getting rid of copies. For video decoding on the GPU, processing o

In my experience memory is very slow on the RPis... I'm talking factor if 10 improvements by getting rid of copies. For video decoding on the GPU, processing on the same GPU memory in place and then displaying takes significantly less work than decoding on the CPU copying to the GPU and doing the rest their and most of the time is in the copy.