Slow opening of the photo

[guglovich]

My iPhone photo opens for about 2s. Other much heavier files open immediately. Will the speed be optimised in the future or is it no longer better?

[bigcat88]

Can someone post an image example from iPhone that opens in "2 seconds"?

[guglovich]

Now there are no files nearby, I asked people, but not yet. Found an old benchmark, it was made by me and the author PhotoQt. https://gitlab.com/lspies/photoqt/-/issues/110

[tbertels]

Here are two images in a ZIP file: one in HEIF (slow to open) and the same one converted to JPEG (fast to open). Slow opening comparison.zip

[cvinhaes]

Same issue here, jpg and CR2 raw are fast, instantaneous, while iphone heif takes about 3 seconds to show and makes browsing my library a real pain.

[bigcat88]

Here are two images in a ZIP file: one in HEIF (slow to open) and the same one converted to JPEG (fast to open). Slow opening comparison.zip

pillow_heif.register_heif_opener()

if __name__ == "__main__":
    pillow_heif.options.DECODE_THREADS = 1
    start_time = time_ns()
    p = "20230117_161524.heic"
    im = Image.open(p)
    im.load()
    print(f"Time: {(time_ns() - start_time) / 1e9}")
    exit(0)

Time: 0.677469

pillow_heif.options.DECODE_THREADS = 6

Time: 0.16587

Apple M2

Note: By default libheif uses 4 threads, afaik.

It can be faster, when libheif will have flag to not rotate image or when someone will make a PR with fast rotation implementation.