On Mon, May 19, 2025 at 09:50:18PM +0200, Dmitriy Kovalenko wrote: > I've found quite a few ways to optimize existing ffmpeg's rgb to yuv > subsampled conversion. In this patch stack I'll try to > improve the performance. > > This particular set of changes is a small improvement to all the > existing functions and macro. The biggest performance gain is > coming from post loading increment of the pointer and immediate > pref etching of the memory blocks and interleaving the multiplication > shifting operations of > different registers for better scheduling. > > Also changed a bunch of places where cmp + b.le was used instead > of one instruction cbnz/tbnz and some other small cleanups. > > Here are checkasm results on the macbook pro with the latest M4 max > > <before> > > bgra_to_uv_1080_c: 257.5 ( 1.00x) > bgra_to_uv_1080_neon: 211.9 ( 1.22x) > bgra_to_uv_1920_c: 467.1 ( 1.00x) > bgra_to_uv_1920_neon: 379.3 ( 1.23x) > bgra_to_uv_half_1080_c: 198.9 ( 1.00x) > bgra_to_uv_half_1080_neon: 125.7 ( 1.58x) > bgra_to_uv_half_1920_c: 346.3 ( 1.00x) > bgra_to_uv_half_1920_neon: 223.7 ( 1.55x) > > <after> > > bgra_to_uv_1080_c: 268.3 ( 1.00x) > bgra_to_uv_1080_neon: 176.0 ( 1.53x) > bgra_to_uv_1920_c: 456.6 ( 1.00x) > bgra_to_uv_1920_neon: 307.7 ( 1.48x) > bgra_to_uv_half_1080_c: 193.2 ( 1.00x) > bgra_to_uv_half_1080_neon: 96.8 ( 2.00x) > bgra_to_uv_half_1920_c: 347.2 ( 1.00x) > bgra_to_uv_half_1920_neon: 182.6 ( 1.92x) > > With my proprietary test on IOS it gives around 70% of performance > improvement converting bgra 1920x1920 image to yuv420p > > On my linux arm cortex-r processing the performance improvement not that > visible but still consistently faster by 5-10% than the current > implementation. > > Signed-off-by: Dmitriy Kovalenko <dmtr.kovale...@outlook.com> > --- > libswscale/aarch64/input.S | 166 +++++++++++++++++++++++++------------ > 1 file changed, 112 insertions(+), 54 deletions(-) > > diff --git a/libswscale/aarch64/input.S b/libswscale/aarch64/input.S > index c1c0adffc8..ee8eb24c14 100644 > --- a/libswscale/aarch64/input.S > +++ b/libswscale/aarch64/input.S > @@ -1,5 +1,4 @@ > -/* > - * Copyright (c) 2024 Zhao Zhili <quinkbl...@foxmail.com> > +/* Copyright (c) 2024 Zhao Zhili <quinkbl...@foxmail.com> > * > * This file is part of FFmpeg. > * > @@ -57,20 +56,41 @@ > sqshrn2 \dst\().8h, \dst2\().4s, \right_shift // > dst_higher_half = dst2 >> right_shift > .endm > +// interleaved product version of the rgb to yuv gives slightly better > performance on non-performant mobile +.macro rgb_to_uv_interleaved_product > r, g, b, u_coef0, u_coef1, u_coef2, v_coef0, v_coef1, v_coef2, u_dst1, > u_dst2, v_dst1, v_dst2, u_dst, v_dst, right_shift
error: corrupt patch at line 58 please make sure your line/word wrap settings dont damage patches [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB During times of universal deceit, telling the truth becomes a revolutionary act. -- George Orwell
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