Implementing multithreading

[C0rn3j]

I took a music cover and ran the 2x example test, generating a 13 MB JXL.

This takes a VERY long time to load via jxlpy

In comparison for example with nomacs, which takes less than five times what jxlpy does due to using multiple threads.

Would it be feasible to make this library use multiple threads? I was trying to use an application with Pillow and this extension, and loading this image made the startup time very long.

[olokelo]

Hi!

Firstly, sorry for late response, I've got a rather busy week. Secondly, Thank you so much for adding my library to AUR :)

I also have some good news, your issue can be easily resolved by providing num_threads parameter to JXLPyDecoder.

import jxlpy
import time
import multiprocessing

CPU_COUNT = multiprocessing.cpu_count()

with open('cover_2x.jxl', 'rb') as f:
    data = f.read()

def decode_default():
    dec = jxlpy.JXLPyDecoder(data)
    output = dec.get_frame()
    dec.close()

def decode_multi():
    dec = jxlpy.JXLPyDecoder(data, num_threads=CPU_COUNT)
    output = dec.get_frame()
    dec.close()

for fun in (decode_default, decode_multi):
    old_time = time.time()
    fun()
    print('{}: {}'.format(fun.__name__, time.time()-old_time))

decode_default: 8.677569150924683
decode_multi: 0.7362372875213623