[homm]

Well, 3680x2456 / 0.06 seconds ≈ 150 Mp/s or 75 Mp/s/per core. Pillow-SIMD's current implementation runs on ≈ 700 Mp/s/pre core for bicubic (which is closer to this implementation).

Obviously, your implementation could be further optimized, but quality drawbacks will remain the same.

[pedrocr]

I've since made a small change that doubled performance and I'm operating on >5x more data per pixel (32x4 vs 8x3). So a 10x factor makes this already faster without any explicit SIMD yet. Proper benchmarking on the same machine would need to be done obviously.

On the quality drawbacks I'd have to do some more checking. This algorithm is closest to what the image would be if you had a camera with that native sensor size. The standard filtering approach may very well have plenty of cases where it produces better output but it can also cause issues so I wonder if this isn't a conservative solution.