fmtconv vs zimg (resize)

resizer_speed.md

Environment:

Intel Core i7-6700HQ @ 2.60GHz, 8 GB DDR4-2133 x2,

Windows 10 1809, VapourSynth R44 64bit, fmtconv r20(CRC: 6EEDD665)

Result:

Input dimensions	Output dimensions	Format	Backend	FPS
1920 x 1080	1280 x 720	GRAY8	zimg	920
1920 x 1080	1280 x 720	GRAY8	fmtconv	700
1920 x 1080	1280 x 720	GRAY16	zimg	865
1920 x 1080	1280 x 720	GRAY16	fmtconv	680
1920 x 1080	1280 x 720	GRAYS	zimg	670
1920 x 1080	1280 x 720	GRAYS	fmtconv	530
1280 x 720	1920 x 1080	GRAY8	zimg	920
1280 x 720	1920 x 1080	GRAY8	fmtconv	535
1280 x 720	1920 x 1080	GRAY16	zimg	920
1280 x 720	1920 x 1080	GRAY16	fmtconv	750
1280 x 720	1920 x 1080	GRAYS	zimg	770
1280 x 720	1920 x 1080	GRAYS	fmtconv	570

resizer_test.vpy

import vapoursynth as vs

core = vs.get_core(threads=8)
core.max_cache_size = 8000

# params
test_id = 5
length = 10000
use_zimg = False

param_list = [
    dict(in_w=1920, in_h=1080, out_w=1280, out_h=720, format=vs.GRAY8), 
    dict(in_w=1920, in_h=1080, out_w=1280, out_h=720, format=vs.GRAY16), 
    dict(in_w=1920, in_h=1080, out_w=1280, out_h=720, format=vs.GRAYS), 
    dict(in_w=1280, in_h=720, out_w=1920, out_h=1080, format=vs.GRAY8), 
    dict(in_w=1280, in_h=720, out_w=1920, out_h=1080, format=vs.GRAY16), 
    dict(in_w=1280, in_h=720, out_w=1920, out_h=1080, format=vs.GRAYS)
    ]


if test_id >= len(param_list):
    raise ValueError(f'"test_id" is {test_id}, while only {len(param_list)} params are given')


# process
src = core.std.BlankClip(width=param_list[test_id]['in_w'], height=param_list[test_id]['in_h'], format=param_list[test_id]['format'], length=length)

if use_zimg:
    res = core.resize.Bicubic(src, param_list[test_id]['out_w'], param_list[test_id]['out_h'], filter_param_a=0, filter_param_b=0.5)
else:
    res = core.fmtc.resample(src, param_list[test_id]['out_w'], param_list[test_id]['out_h'], kernel='bicubic', a1=0, a2=0.5)

if res.format.bits_per_sample != src.format.bits_per_sample:
    res = core.fmtc.bitdepth(res, bits=src.format.bits_per_sample)

res.set_output()