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https://chromium.googlesource.com/libyuv/libyuv
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The original main loop builds v0-v3 with four lane-indexed LD4 load
instructions. Since the first LD4 only updates lane 0, it retains a
false dependency on the registers produced by the previous loop
iteration, leading to a large performance penalty on larger out-of-order
micro-architectures.
Replace the first LD4 with two scalar-register LDPs to zero the top part
of the four registers, breaking the loop-carried dependency.
Performance versus the existing Neon code, higher is better:
Cortex-A55: 0.993x
Cortex-A510: 1.072x
Cortex-A720: 0.999x
Cortex-X4: 1.052x
C1-Nano: 2.093x
C1-Pro: 2.011x
C1-Ultra: 2.128x
Change-Id: Ib5d71e8150d7b11048ddf0fb91e107f9c9323a3f
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| build_overrides | ||
| docs | ||
| include | ||
| infra/config | ||
| riscv_script | ||
| source | ||
| tools_libyuv | ||
| unit_test | ||
| util | ||
| .clang-format | ||
| .gitignore | ||
| .gn | ||
| Android.bp | ||
| Android.mk | ||
| AUTHORS | ||
| BUILD.bazel | ||
| BUILD.gn | ||
| CM_linux_packages.cmake | ||
| CMakeLists.txt | ||
| codereview.settings | ||
| DEPS | ||
| DIR_METADATA | ||
| download_vs_toolchain.py | ||
| GEMINI.md | ||
| libyuv.bzl | ||
| libyuv.gni | ||
| libyuv.gyp | ||
| libyuv.gypi | ||
| LICENSE | ||
| linux.mk | ||
| OWNERS | ||
| PATENTS | ||
| PRESUBMIT.py | ||
| public.mk | ||
| pylintrc | ||
| README.chromium | ||
| README.md | ||
| vpython.toml | ||
| vpython.toml.uv.lock | ||
| winarm.mk | ||
| WORKSPACE.bazel | ||
libyuv is an open source project that includes YUV scaling and conversion functionality.
- Scale YUV to prepare content for compression, with point, bilinear or box filter.
- Convert to YUV from webcam formats for compression.
- Convert to RGB formats for rendering/effects.
- Rotate by 90/180/270 degrees to adjust for mobile devices in portrait mode.
- Optimized for SSSE3/AVX2 on x86/x64.
- Optimized for Neon/SVE2/SME on Arm.
- Optimized for MSA on Mips.
- Optimized for RVV on RISC-V.
Development
See Getting started for instructions on how to get started developing.
You can also browse the docs directory for more documentation.