kc3-lang/SDL/test/testyuv_cvt.c

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• Hash : a6a4e27a
  Author :
  Date : 2017-11-12T22:51:12
  

  Updated SDL's YUV support, many thanks to Adrien Descamps New functions get and set the YUV colorspace conversion mode: SDL_SetYUVConversionMode() SDL_GetYUVConversionMode() SDL_GetYUVConversionModeForResolution() SDL_ConvertPixels() converts between all supported RGB and YUV formats, with SSE acceleration for converting from planar YUV formats (YV12, NV12, etc) to common RGB/RGBA formats. Added a new test program, testyuv, to verify correctness and speed of YUV conversion functionality.

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• test/testyuv_cvt.c

• /*
    Copyright (C) 1997-2017 Sam Lantinga <slouken@libsdl.org>
  
    This software is provided 'as-is', without any express or implied
    warranty.  In no event will the authors be held liable for any damages
    arising from the use of this software.
  
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely.
  */
  
  #include "SDL.h"
  
  #include "testyuv_cvt.h"
  
  
  static float clip3(float x, float y, float z)
  {
      return ((z < x) ? x : ((z > y) ? y : z));
  }
  
  static void RGBtoYUV(Uint8 * rgb, int *yuv, SDL_YUV_CONVERSION_MODE mode, int monochrome, int luminance)
  {
      if (mode == SDL_YUV_CONVERSION_JPEG) {
          /* Full range YUV */
          yuv[0] = (int)(0.299 * rgb[0] + 0.587 * rgb[1] + 0.114 * rgb[2]);
          yuv[1] = (int)((rgb[2] - yuv[0]) * 0.565 + 128);
          yuv[2] = (int)((rgb[0] - yuv[0]) * 0.713 + 128);
      } else {
          // This formula is from Microsoft's documentation:
          // https://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx
          // L = Kr * R + Kb * B + (1 - Kr - Kb) * G
          // Y =                   floor(2^(M-8) * (219*(L-Z)/S + 16) + 0.5);
          // U = clip3(0, (2^M)-1, floor(2^(M-8) * (112*(B-L) / ((1-Kb)*S) + 128) + 0.5));
          // V = clip3(0, (2^M)-1, floor(2^(M-8) * (112*(R-L) / ((1-Kr)*S) + 128) + 0.5));
          float S, Z, R, G, B, L, Kr, Kb, Y, U, V;
  
          if (mode == SDL_YUV_CONVERSION_BT709) {
              /* BT.709 */
              Kr = 0.2126f;
              Kb = 0.0722f;
          } else {
              /* BT.601 */
              Kr = 0.299f;
              Kb = 0.114f;
          }
  
          S = 255.0f;
          Z = 0.0f;
          R = rgb[0];
          G = rgb[1];
          B = rgb[2];
          L = Kr * R + Kb * B + (1 - Kr - Kb) * G;
          Y = (Uint8)SDL_floorf((219*(L-Z)/S + 16) + 0.5f);
          U = (Uint8)clip3(0, 255, SDL_floorf((112.0f*(B-L) / ((1.0f-Kb)*S) + 128) + 0.5f));
          V = (Uint8)clip3(0, 255, SDL_floorf((112.0f*(R-L) / ((1.0f-Kr)*S) + 128) + 0.5f));
  
          yuv[0] = (Uint8)Y;
          yuv[1] = (Uint8)U;
          yuv[2] = (Uint8)V;
      }
  
      if (monochrome) {
          yuv[1] = 128;
          yuv[2] = 128;
      }
  
      if (luminance != 100) {
          yuv[0] = yuv[0] * luminance / 100;
          if (yuv[0] > 255)
              yuv[0] = 255;
      }
  }
  
  static void ConvertRGBtoPlanar2x2(Uint32 format, Uint8 *src, int pitch, Uint8 *out, int w, int h, SDL_YUV_CONVERSION_MODE mode, int monochrome, int luminance)
  {
      int x, y;
      int yuv[4][3];
      Uint8 *Y1, *Y2, *U, *V;
      Uint8 *rgb1, *rgb2;
      int rgb_row_advance = (pitch - w*3) + pitch;
      int UV_advance;
  
      rgb1 = src;
      rgb2 = src + pitch;
  
      Y1 = out;
      Y2 = Y1 + w;
      switch (format) {
      case SDL_PIXELFORMAT_YV12:
          V = (Y1 + h * w);
          U = V + ((h + 1)/2)*((w + 1)/2);
          UV_advance = 1;
          break;
      case SDL_PIXELFORMAT_IYUV:
          U = (Y1 + h * w);
          V = U + ((h + 1)/2)*((w + 1)/2);
          UV_advance = 1;
          break;
      case SDL_PIXELFORMAT_NV12:
          U = (Y1 + h * w);
          V = U + 1;
          UV_advance = 2;
          break;
      case SDL_PIXELFORMAT_NV21:
          V = (Y1 + h * w);
          U = V + 1;
          UV_advance = 2;
          break;
      default:
          SDL_assert(!"Unsupported planar YUV format");
          return;
      }
  
      for (y = 0; y < (h - 1); y += 2) {
          for (x = 0; x < (w - 1); x += 2) {
              RGBtoYUV(rgb1, yuv[0], mode, monochrome, luminance);
              rgb1 += 3;
              *Y1++ = (Uint8)yuv[0][0];
  
              RGBtoYUV(rgb1, yuv[1], mode, monochrome, luminance);
              rgb1 += 3;
              *Y1++ = (Uint8)yuv[1][0];
  
              RGBtoYUV(rgb2, yuv[2], mode, monochrome, luminance);
              rgb2 += 3;
              *Y2++ = (Uint8)yuv[2][0];
  
              RGBtoYUV(rgb2, yuv[3], mode, monochrome, luminance);
              rgb2 += 3;
              *Y2++ = (Uint8)yuv[3][0];
  
              *U = (Uint8)SDL_floorf((yuv[0][1] + yuv[1][1] + yuv[2][1] + yuv[3][1])/4.0f + 0.5f);
              U += UV_advance;
  
              *V = (Uint8)SDL_floorf((yuv[0][2] + yuv[1][2] + yuv[2][2] + yuv[3][2])/4.0f + 0.5f);
              V += UV_advance;
          }
          /* Last column */
          if (x == (w - 1)) {
              RGBtoYUV(rgb1, yuv[0], mode, monochrome, luminance);
              rgb1 += 3;
              *Y1++ = (Uint8)yuv[0][0];
  
              RGBtoYUV(rgb2, yuv[2], mode, monochrome, luminance);
              rgb2 += 3;
              *Y2++ = (Uint8)yuv[2][0];
  
              *U = (Uint8)SDL_floorf((yuv[0][1] + yuv[2][1])/2.0f + 0.5f);
              U += UV_advance;
  
              *V = (Uint8)SDL_floorf((yuv[0][2] + yuv[2][2])/2.0f + 0.5f);
              V += UV_advance;
          }
          Y1 += w;
          Y2 += w;
          rgb1 += rgb_row_advance;
          rgb2 += rgb_row_advance;
      }
      /* Last row */
      if (y == (h - 1)) {
          for (x = 0; x < (w - 1); x += 2) {
              RGBtoYUV(rgb1, yuv[0], mode, monochrome, luminance);
              rgb1 += 3;
              *Y1++ = (Uint8)yuv[0][0];
  
              RGBtoYUV(rgb1, yuv[1], mode, monochrome, luminance);
              rgb1 += 3;
              *Y1++ = (Uint8)yuv[1][0];
  
              *U = (Uint8)SDL_floorf((yuv[0][1] + yuv[1][1])/2.0f + 0.5f);
              U += UV_advance;
  
              *V = (Uint8)SDL_floorf((yuv[0][2] + yuv[1][2])/2.0f + 0.5f);
              V += UV_advance;
          }
          /* Last column */
          if (x == (w - 1)) {
              RGBtoYUV(rgb1, yuv[0], mode, monochrome, luminance);
              *Y1++ = (Uint8)yuv[0][0];
  
              *U = (Uint8)yuv[0][1];
              U += UV_advance;
  
              *V = (Uint8)yuv[0][2];
              V += UV_advance;
          }
      }
  }
  
  static void ConvertRGBtoPacked4(Uint32 format, Uint8 *src, int pitch, Uint8 *out, int w, int h, SDL_YUV_CONVERSION_MODE mode, int monochrome, int luminance)
  {
      int x, y;
      int yuv[2][3];
      Uint8 *Y1, *Y2, *U, *V;
      Uint8 *rgb;
      int rgb_row_advance = (pitch - w*3);
  
      rgb = src;
  
      switch (format) {
      case SDL_PIXELFORMAT_YUY2:
          Y1 = out;
          U = out+1;
          Y2 = out+2;
          V = out+3;
          break;
      case SDL_PIXELFORMAT_UYVY:
          U = out;
          Y1 = out+1;
          V = out+2;
          Y2 = out+3;
          break;
      case SDL_PIXELFORMAT_YVYU:
          Y1 = out;
          V = out+1;
          Y2 = out+2;
          U = out+3;
          break;
      default:
          SDL_assert(!"Unsupported packed YUV format");
          return;
      }
  
      for (y = 0; y < h; ++y) {
          for (x = 0; x < (w - 1); x += 2) {
              RGBtoYUV(rgb, yuv[0], mode, monochrome, luminance);
              rgb += 3;
              *Y1 = (Uint8)yuv[0][0];
              Y1 += 4;
  
              RGBtoYUV(rgb, yuv[1], mode, monochrome, luminance);
              rgb += 3;
              *Y2 = (Uint8)yuv[1][0];
              Y2 += 4;
  
              *U = (Uint8)SDL_floorf((yuv[0][1] + yuv[1][1])/2.0f + 0.5f);
              U += 4;
  
              *V = (Uint8)SDL_floorf((yuv[0][2] + yuv[1][2])/2.0f + 0.5f);
              V += 4;
          }
          /* Last column */
          if (x == (w - 1)) {
              RGBtoYUV(rgb, yuv[0], mode, monochrome, luminance);
              rgb += 3;
              *Y2 = *Y1 = (Uint8)yuv[0][0];
              Y1 += 4;
              Y2 += 4;
  
              *U = (Uint8)yuv[0][1];
              U += 4;
  
              *V = (Uint8)yuv[0][2];
              V += 4;
          }
          rgb += rgb_row_advance;
      }
  }
  
  SDL_bool ConvertRGBtoYUV(Uint32 format, Uint8 *src, int pitch, Uint8 *out, int w, int h, SDL_YUV_CONVERSION_MODE mode, int monochrome, int luminance)
  {
      switch (format)
      {
      case SDL_PIXELFORMAT_YV12:
      case SDL_PIXELFORMAT_IYUV:
      case SDL_PIXELFORMAT_NV12:
      case SDL_PIXELFORMAT_NV21:
          ConvertRGBtoPlanar2x2(format, src, pitch, out, w, h, mode, monochrome, luminance);
          return SDL_TRUE;
      case SDL_PIXELFORMAT_YUY2:
      case SDL_PIXELFORMAT_UYVY:
      case SDL_PIXELFORMAT_YVYU:
          ConvertRGBtoPacked4(format, src, pitch, out, w, h, mode, monochrome, luminance);
          return SDL_TRUE;
      default:
          return SDL_FALSE;
      }
  }
  
  int CalculateYUVPitch(Uint32 format, int width)
  {
      switch (format)
      {
      case SDL_PIXELFORMAT_YV12:
      case SDL_PIXELFORMAT_IYUV:
      case SDL_PIXELFORMAT_NV12:
      case SDL_PIXELFORMAT_NV21:
          return width;
      case SDL_PIXELFORMAT_YUY2:
      case SDL_PIXELFORMAT_UYVY:
      case SDL_PIXELFORMAT_YVYU:
          return 4*((width + 1)/2);
      default:
          return 0;
      }
  }
  
  /* vi: set ts=4 sw=4 expandtab: */
  

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