When loading an EXR image, first we were allocating memory for it,
then clearing it to zero, then using OpenEXR to load the data. But
the process of loading will overwrite all the pixel values anyway,
so it is pointless to do the first clear.
On a test VSE file that has two 1920x1080 EXR image sequences blended
together, plus some color correction on top, playback framerate of it:
- PC: 12.6 -> 13.2 FPS (Ryzen 5950X, RAM bandwidth ~32GB/s)
- Mac: 27.3 -> 29.5 FPS (M1 Max, RAM bandwidth ~400GB/s)
Pull Request: https://projects.blender.org/blender/blender/pulls/127427
3af3c94ec6