77 lines
2.5 KiB
C++
77 lines
2.5 KiB
C++
/*
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OpenPnp-Capture: a video capture subsystem.
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Linux platform code
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YUV to RGB conversion routines
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Created by Niels Moseley on 9/21/17.
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Copyright (c) 2017 Jason von Nieda, Niels Moseley.
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#include "yuvconverters.h"
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static inline uint8_t clamp(int16_t v)
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{
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v = (v > 255) ? 255 : v;
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v = (v < 0) ? 0 : v;
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return v;
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}
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/*
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In the YUYV2/YUV2 pixel, the order of the fields is:
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Y0 | Cr | Y1 | Cb ... repeating, which encode two 24-bit pixels.
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perfect:
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B = 1.164(Y - 16) + 2.018(U - 128)
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G = 1.164(Y - 16) - 0.813(V - 128) - 0.391(U - 128)
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R = 1.164(Y - 16) + 1.596(V - 128)
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or:
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R = Y + 1.403V'
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G = Y - 0.344U' - 0.714V'
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B = Y + 1.770U'
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*/
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void YUYV2RGB(const uint8_t *yuv, uint8_t *rgb, uint32_t bytes)
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{
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while(bytes > 3)
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{
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int16_t y0 = *yuv++; // Y0
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int16_t cr = *yuv++; // Cr (aka U)
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int16_t y1 = *yuv++; // Y1
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int16_t cb = *yuv++; // Cb (aka V)
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int16_t yy0 = 19*(y0 - 16);
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int16_t yy1 = 19*(y1 - 16);
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*rgb++ = clamp((yy0 + 32*(cb - 128)) >> 4);
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*rgb++ = clamp((yy0 - 13*(cr - 128) - 6*(cb - 128)) >> 4);
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*rgb++ = clamp((yy0 + 26*(cr - 128) ) >> 4);
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*rgb++ = clamp((yy1 + 32*(cb - 128)) >> 4);
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*rgb++ = clamp((yy1 - 13*(cr - 128) - 6*(cb - 128)) >> 4);
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*rgb++ = clamp((yy1 + 26*(cr - 128) ) >> 4);
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bytes -= 4;
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}
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}
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