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AR30 is optimized with 3 techniques 1. vpmulhuw is used to replicate 8 bits to 10 bits. 2. Two channels are processed at a time. R and B, and A and G. 3. vpshufb is used to shift and mask 2 channels of R and B Red Blue With the 8 bit value in the upper bits, vpmulhuw by (1024+4) will produce a 10 bit value in the low 10 bits of each 16 bit value. This is whats wanted for the blue channel. The red needs to be shifted 4 left, so multiply by (1024+4)*16 for red. Alpha Green Alpha and Green are already in the high bits so vpand can zero out the other bits, keeping just 2 upper bits of alpha and 8 bit green. The same multiplier could be used for Green - (1024+4) putting the 10 bit green in the lsb. Alpha would be a simple multiplier to shift it into position. It wants a gap of 10 above the green. Green is 10 bits, so there are 6 bits in the low short. 4 more are needed, so a multiplier of 4 gets the 2 bits into the upper 16 bits, and then a shift of 4 is a multiply of 16, so (4*16) = 64. Then shift the result left 10 to position the A and G channels. Bug: libyuv:751 Test: ARGBToAR30_Opt Change-Id: Ie4f20dce18203bae7b75acb1fd5232db8a8a4f11 Reviewed-on: https://chromium-review.googlesource.com/820046 Commit-Queue: Frank Barchard <fbarchard@chromium.org> Reviewed-by: Cheng Wang <wangcheng@google.com> |
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| include | ||
| infra/config | ||
| source | ||
| tools_libyuv | ||
| unit_test | ||
| util | ||
| .clang-format | ||
| .gitignore | ||
| .gn | ||
| .vpython | ||
| all.gyp | ||
| Android.bp | ||
| Android.mk | ||
| AUTHORS | ||
| BUILD.gn | ||
| cleanup_links.py | ||
| CM_linux_packages.cmake | ||
| CMakeLists.txt | ||
| codereview.settings | ||
| DEPS | ||
| download_vs_toolchain.py | ||
| gyp_libyuv | ||
| gyp_libyuv.py | ||
| libyuv_nacl.gyp | ||
| libyuv_test.gyp | ||
| libyuv.gni | ||
| libyuv.gyp | ||
| libyuv.gypi | ||
| LICENSE | ||
| LICENSE_THIRD_PARTY | ||
| 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.
- Convert from YUV to formats for rendering/effects.
- Rotate by 90/180/270 degrees to adjust for mobile devices in portrait mode.
- Optimized for SSE2/SSSE3/AVX2 on x86/x64.
- Optimized for Neon on Arm.
- Optimized for DSP R2 on Mips.
Development
See [Getting started] 1 for instructions on how to get started developing.
You can also browse the [docs directory] 2 for more documentation.