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https://chromium.googlesource.com/libyuv/libyuv
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The existing C implementation compiled with a recent LLVM is
auto-vectorised and unrolled to process four vectors per loop iteration,
making the Neon implementation slower than the C implementation on
little cores. To avoid this, unroll the Neon implementation to also
process four vectors per iteration.
Reduction in cycle counts observed compared to the existing Neon
implementation:
| HalfFloat1Row_NEON | HalfFloatRow_NEON
Cortex-A510 | -37.1% | -40.8%
Cortex-A520 | -32.3% | -37.4%
Cortex-A720 | 0.0% | -10.6%
Cortex-X2 | 0.0% | -7.8%
Cortex-X4 | +0.3% | -6.9%
Bug: b/42280945
Change-Id: I12b474c970fc4355d75ed924c4ca6169badda2bc
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/5872805
Reviewed-by: Frank Barchard <fbarchard@chromium.org>
Reviewed-by: Justin Green <greenjustin@google.com>
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| build_overrides | ||
| docs | ||
| include | ||
| infra/config | ||
| riscv_script | ||
| source | ||
| tools_libyuv | ||
| unit_test | ||
| util | ||
| .clang-format | ||
| .gitignore | ||
| .gn | ||
| .vpython | ||
| .vpython3 | ||
| Android.bp | ||
| Android.mk | ||
| AUTHORS | ||
| BUILD.gn | ||
| CM_linux_packages.cmake | ||
| CMakeLists.txt | ||
| codereview.settings | ||
| DEPS | ||
| DIR_METADATA | ||
| download_vs_toolchain.py | ||
| libyuv.gni | ||
| libyuv.gyp | ||
| libyuv.gypi | ||
| LICENSE | ||
| linux.mk | ||
| OWNERS | ||
| PATENTS | ||
| PRESUBMIT.py | ||
| public.mk | ||
| pylintrc | ||
| README.chromium | ||
| README.md | ||
| winarm.mk | ||
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.