gfx/ycbcr/yuv_convert.cpp

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This webpage shows layout of YV12 and other YUV formats
   6 // http://www.fourcc.org/yuv.php
   7 // The actual conversion is best described here
   8 // http://en.wikipedia.org/wiki/YUV
   9 // An article on optimizing YUV conversion using tables instead of multiplies
  10 // http://lestourtereaux.free.fr/papers/data/yuvrgb.pdf
  11 //
  12 // YV12 is a full plane of Y and a half height, half width chroma planes
  13 // YV16 is a full plane of Y and a full height, half width chroma planes
  14 // YV24 is a full plane of Y and a full height, full width chroma planes
  15 // Y8   is a full plane of Y and no chroma planes (i.e., monochrome)
  16 //
  17 // ARGB pixel format is output, which on little endian is stored as BGRA.
  18 // The alpha is set to 255, allowing the application to use RGBA or RGB32.
  19
  20 #include "yuv_convert.h"
  21
  22 #include "mozilla/StaticPrefs_gfx.h"
  23 #include "libyuv.h"
  24 #include "scale_yuv_argb.h"
  25 // Header for low level row functions.
  26 #include "yuv_row.h"
  27 #include "mozilla/SSE.h"
  28 #include "mozilla/IntegerRange.h"
  29
  30 namespace mozilla {
  31
  32 namespace gfx {
  33
  34 // 16.16 fixed point arithmetic
  35 const int kFractionBits = 16;
  36 const int kFractionMax = 1 << kFractionBits;
  37 const int kFractionMask = ((1 << kFractionBits) - 1);
  38
  39 // clang-format off
  40
  41 libyuv::FourCC FourCCFromYUVType(YUVType aYUVType) {
  42   switch (aYUVType) {
  43     case YV24: return libyuv::FOURCC_I444;
  44     case YV16: return libyuv::FOURCC_I422;
  45     case YV12: return libyuv::FOURCC_I420;
  46     case   Y8: return libyuv::FOURCC_I400;
  47     default:   return libyuv::FOURCC_ANY;
  48   }
  49 }
  50
  51 int GBRPlanarToARGB(const uint8_t* src_y, int y_pitch,
  52                      const uint8_t* src_u, int u_pitch,
  53                      const uint8_t* src_v, int v_pitch,
  54                      uint8_t* rgb_buf, int rgb_pitch,
  55                      int pic_width, int pic_height) {
  56   // libyuv has no native conversion function for this
  57   // fixme: replace with something less awful
  58   for (const auto row : IntegerRange(pic_height)) {
  59     for (const auto col : IntegerRange(pic_width)) {
  60       rgb_buf[rgb_pitch * row + col * 4 + 0] = src_u[u_pitch * row + col];
  61       rgb_buf[rgb_pitch * row + col * 4 + 1] = src_y[y_pitch * row + col];
  62       rgb_buf[rgb_pitch * row + col * 4 + 2] = src_v[v_pitch * row + col];
  63       rgb_buf[rgb_pitch * row + col * 4 + 3] = 255;
  64     }
  65   }
  66   return 0;
  67 }
  68
  69 // Convert a frame of YUV to 32 bit ARGB.
  70 void ConvertYCbCrToRGB32(const uint8_t* y_buf, const uint8_t* u_buf,
  71                          const uint8_t* v_buf, uint8_t* rgb_buf, int pic_x,
  72                          int pic_y, int pic_width, int pic_height, int y_pitch,
  73                          int uv_pitch, int rgb_pitch, YUVType yuv_type,
  74                          YUVColorSpace yuv_color_space,
  75                          ColorRange color_range) {
  76   // Deprecated function's conversion is accurate.
  77   // libyuv converion is a bit inaccurate to get performance. It dynamically
  78   // calculates RGB from YUV to use simd. In it, signed byte is used for
  79   // conversion's coefficient, but it requests 129. libyuv cut 129 to 127. And
  80   // only 6 bits are used for a decimal part during the dynamic calculation.
  81   //
  82   // The function is still fast on some old intel chips.
  83   // See Bug 1256475.
  84   bool use_deprecated = StaticPrefs::gfx_ycbcr_accurate_conversion() ||
  85                         (supports_mmx() && supports_sse() && !supports_sse3() &&
  86                          yuv_color_space == YUVColorSpace::BT601 &&
  87                          color_range == ColorRange::LIMITED);
  88   // The deprecated function only support BT601.
  89   // See Bug 1210357.
  90   if (yuv_color_space != YUVColorSpace::BT601) {
  91     use_deprecated = false;
  92   }
  93   if (use_deprecated) {
  94     ConvertYCbCrToRGB32_deprecated(y_buf, u_buf, v_buf, rgb_buf, pic_x, pic_y,
  95                                    pic_width, pic_height, y_pitch, uv_pitch,
  96                                    rgb_pitch, yuv_type);
  97     return;
  98   }
  99
 100   decltype(libyuv::I420ToARGBMatrix)* fConvertYUVToARGB = nullptr;
 101   const uint8_t* src_y = nullptr;
 102   const uint8_t* src_u = nullptr;
 103   const uint8_t* src_v = nullptr;
 104   const libyuv::YuvConstants* yuv_constant = nullptr;
 105
 106   switch (yuv_color_space) {
 107     case YUVColorSpace::BT2020:
 108       yuv_constant = color_range == ColorRange::LIMITED
 109         ? &libyuv::kYuv2020Constants
 110         : &libyuv::kYuvV2020Constants;
 111       break;
 112     case YUVColorSpace::BT709:
 113       yuv_constant = color_range == ColorRange::LIMITED
 114         ? &libyuv::kYuvH709Constants
 115         : &libyuv::kYuvF709Constants;
 116       break;
 117     case YUVColorSpace::Identity:
 118       MOZ_ASSERT(yuv_type == YV24, "Identity (aka RGB) with chroma subsampling is unsupported");
 119       if (yuv_type == YV24) {
 120         break;
 121       }
 122       [[fallthrough]]; // Assuming BT601 for unsupported input is better than crashing
 123     default:
 124       MOZ_FALLTHROUGH_ASSERT("Unsupported YUVColorSpace");
 125     case YUVColorSpace::BT601:
 126       yuv_constant = color_range == ColorRange::LIMITED
 127         ? &libyuv::kYuvI601Constants
 128         : &libyuv::kYuvJPEGConstants;
 129       break;
 130   }
 131
 132   switch (yuv_type) {
 133     case YV24: {
 134       src_y = y_buf + y_pitch * pic_y + pic_x;
 135       src_u = u_buf + uv_pitch * pic_y + pic_x;
 136       src_v = v_buf + uv_pitch * pic_y + pic_x;
 137
 138       if (yuv_color_space == YUVColorSpace::Identity) {
 139         // Special case for RGB image
 140         DebugOnly<int> err =
 141           GBRPlanarToARGB(src_y, y_pitch, src_u, uv_pitch, src_v, uv_pitch,
 142                             rgb_buf, rgb_pitch, pic_width, pic_height);
 143         MOZ_ASSERT(!err);
 144         return;
 145       }
 146
 147       fConvertYUVToARGB = libyuv::I444ToARGBMatrix;
 148       break;
 149     }
 150     case YV16: {
 151       src_y = y_buf + y_pitch * pic_y + pic_x;
 152       src_u = u_buf + uv_pitch * pic_y + pic_x / 2;
 153       src_v = v_buf + uv_pitch * pic_y + pic_x / 2;
 154
 155       fConvertYUVToARGB = libyuv::I422ToARGBMatrix;
 156       break;
 157     }
 158     case YV12: {
 159       src_y = y_buf + y_pitch * pic_y + pic_x;
 160       src_u = u_buf + (uv_pitch * pic_y + pic_x) / 2;
 161       src_v = v_buf + (uv_pitch * pic_y + pic_x) / 2;
 162
 163       fConvertYUVToARGB = libyuv::I420ToARGBMatrix;
 164       break;
 165     }
 166     case Y8: {
 167       src_y = y_buf + y_pitch * pic_y + pic_x;
 168       MOZ_ASSERT(u_buf == nullptr);
 169       MOZ_ASSERT(v_buf == nullptr);
 170
 171       if (color_range == ColorRange::LIMITED) {
 172         DebugOnly<int> err =
 173             libyuv::I400ToARGB(src_y, y_pitch, rgb_buf, rgb_pitch, pic_width,
 174                               pic_height);
 175         MOZ_ASSERT(!err);
 176       } else {
 177         DebugOnly<int> err =
 178             libyuv::J400ToARGB(src_y, y_pitch, rgb_buf, rgb_pitch, pic_width,
 179                               pic_height);
 180         MOZ_ASSERT(!err);
 181       }
 182
 183       return;
 184     }
 185     default:
 186       MOZ_ASSERT_UNREACHABLE("Unsupported YUV type");
 187   }
 188
 189   DebugOnly<int> err =
 190     fConvertYUVToARGB(src_y, y_pitch, src_u, uv_pitch, src_v, uv_pitch,
 191                       rgb_buf, rgb_pitch, yuv_constant, pic_width, pic_height);
 192   MOZ_ASSERT(!err);
 193 }
 194
 195 // Convert a frame of YUV to 32 bit ARGB.
 196 void ConvertYCbCrToRGB32_deprecated(const uint8_t* y_buf,
 197                                     const uint8_t* u_buf,
 198                                     const uint8_t* v_buf,
 199                                     uint8_t* rgb_buf,
 200                                     int pic_x,
 201                                     int pic_y,
 202                                     int pic_width,
 203                                     int pic_height,
 204                                     int y_pitch,
 205                                     int uv_pitch,
 206                                     int rgb_pitch,
 207                                     YUVType yuv_type) {
 208   unsigned int y_shift = yuv_type == YV12 ? 1 : 0;
 209   unsigned int x_shift = yuv_type == YV24 ? 0 : 1;
 210   // Test for SSE because the optimized code uses movntq, which is not part of MMX.
 211   bool has_sse = supports_mmx() && supports_sse();
 212   // There is no optimized YV24 SSE routine so we check for this and
 213   // fall back to the C code.
 214   has_sse &= yuv_type != YV24;
 215   bool odd_pic_x = yuv_type != YV24 && pic_x % 2 != 0;
 216   int x_width = odd_pic_x ? pic_width - 1 : pic_width;
 217
 218   for (int y = pic_y; y < pic_height + pic_y; ++y) {
 219     uint8_t* rgb_row = rgb_buf + (y - pic_y) * rgb_pitch;
 220     const uint8_t* y_ptr = y_buf + y * y_pitch + pic_x;
 221     const uint8_t* u_ptr = u_buf + (y >> y_shift) * uv_pitch + (pic_x >> x_shift);
 222     const uint8_t* v_ptr = v_buf + (y >> y_shift) * uv_pitch + (pic_x >> x_shift);
 223
 224     if (odd_pic_x) {
 225       // Handle the single odd pixel manually and use the
 226       // fast routines for the remaining.
 227       FastConvertYUVToRGB32Row_C(y_ptr++,
 228                                  u_ptr++,
 229                                  v_ptr++,
 230                                  rgb_row,
 231                                  1,
 232                                  x_shift);
 233       rgb_row += 4;
 234     }
 235
 236     if (has_sse) {
 237       FastConvertYUVToRGB32Row(y_ptr,
 238                                u_ptr,
 239                                v_ptr,
 240                                rgb_row,
 241                                x_width);
 242     }
 243     else {
 244       FastConvertYUVToRGB32Row_C(y_ptr,
 245                                  u_ptr,
 246                                  v_ptr,
 247                                  rgb_row,
 248                                  x_width,
 249                                  x_shift);
 250     }
 251   }
 252
 253   // MMX used for FastConvertYUVToRGB32Row requires emms instruction.
 254   if (has_sse)
 255     EMMS();
 256 }
 257
 258 // C version does 8 at a time to mimic MMX code
 259 static void FilterRows_C(uint8_t* ybuf, const uint8_t* y0_ptr, const uint8_t* y1_ptr,
 260                          int source_width, int source_y_fraction) {
 261   int y1_fraction = source_y_fraction;
 262   int y0_fraction = 256 - y1_fraction;
 263   uint8_t* end = ybuf + source_width;
 264   do {
 265     ybuf[0] = (y0_ptr[0] * y0_fraction + y1_ptr[0] * y1_fraction) >> 8;
 266     ybuf[1] = (y0_ptr[1] * y0_fraction + y1_ptr[1] * y1_fraction) >> 8;
 267     ybuf[2] = (y0_ptr[2] * y0_fraction + y1_ptr[2] * y1_fraction) >> 8;
 268     ybuf[3] = (y0_ptr[3] * y0_fraction + y1_ptr[3] * y1_fraction) >> 8;
 269     ybuf[4] = (y0_ptr[4] * y0_fraction + y1_ptr[4] * y1_fraction) >> 8;
 270     ybuf[5] = (y0_ptr[5] * y0_fraction + y1_ptr[5] * y1_fraction) >> 8;
 271     ybuf[6] = (y0_ptr[6] * y0_fraction + y1_ptr[6] * y1_fraction) >> 8;
 272     ybuf[7] = (y0_ptr[7] * y0_fraction + y1_ptr[7] * y1_fraction) >> 8;
 273     y0_ptr += 8;
 274     y1_ptr += 8;
 275     ybuf += 8;
 276   } while (ybuf < end);
 277 }
 278
 279 #ifdef MOZILLA_MAY_SUPPORT_MMX
 280 void FilterRows_MMX(uint8_t* ybuf, const uint8_t* y0_ptr, const uint8_t* y1_ptr,
 281                     int source_width, int source_y_fraction);
 282 #endif
 283
 284 #ifdef MOZILLA_MAY_SUPPORT_SSE2
 285 void FilterRows_SSE2(uint8_t* ybuf, const uint8_t* y0_ptr, const uint8_t* y1_ptr,
 286                      int source_width, int source_y_fraction);
 287 #endif
 288
 289 static inline void FilterRows(uint8_t* ybuf, const uint8_t* y0_ptr,
 290                               const uint8_t* y1_ptr, int source_width,
 291                               int source_y_fraction) {
 292 #ifdef MOZILLA_MAY_SUPPORT_SSE2
 293   if (mozilla::supports_sse2()) {
 294     FilterRows_SSE2(ybuf, y0_ptr, y1_ptr, source_width, source_y_fraction);
 295     return;
 296   }
 297 #endif
 298
 299 #ifdef MOZILLA_MAY_SUPPORT_MMX
 300   if (mozilla::supports_mmx()) {
 301     FilterRows_MMX(ybuf, y0_ptr, y1_ptr, source_width, source_y_fraction);
 302     return;
 303   }
 304 #endif
 305
 306   FilterRows_C(ybuf, y0_ptr, y1_ptr, source_width, source_y_fraction);
 307 }
 308
 309
 310 // Scale a frame of YUV to 32 bit ARGB.
 311 void ScaleYCbCrToRGB32(const uint8_t* y_buf,
 312                        const uint8_t* u_buf,
 313                        const uint8_t* v_buf,
 314                        uint8_t* rgb_buf,
 315                        int source_width,
 316                        int source_height,
 317                        int width,
 318                        int height,
 319                        int y_pitch,
 320                        int uv_pitch,
 321                        int rgb_pitch,
 322                        YUVType yuv_type,
 323                        YUVColorSpace yuv_color_space,
 324                        ScaleFilter filter) {
 325   bool use_deprecated =
 326       StaticPrefs::gfx_ycbcr_accurate_conversion() ||
 327 #if defined(XP_WIN) && defined(_M_X64)
 328       // libyuv does not support SIMD scaling on win 64bit. See Bug 1295927.
 329       supports_sse3() ||
 330 #endif
 331       (supports_mmx() && supports_sse() && !supports_sse3());
 332   // The deprecated function only support BT601.
 333   // See Bug 1210357.
 334   if (yuv_color_space != YUVColorSpace::BT601) {
 335     use_deprecated = false;
 336   }
 337   if (use_deprecated) {
 338     ScaleYCbCrToRGB32_deprecated(y_buf, u_buf, v_buf,
 339                                  rgb_buf,
 340                                  source_width, source_height,
 341                                  width, height,
 342                                  y_pitch, uv_pitch,
 343                                  rgb_pitch,
 344                                  yuv_type,
 345                                  ROTATE_0,
 346                                  filter);
 347     return;
 348   }
 349
 350   DebugOnly<int> err =
 351     libyuv::YUVToARGBScale(y_buf, y_pitch,
 352                            u_buf, uv_pitch,
 353                            v_buf, uv_pitch,
 354                            FourCCFromYUVType(yuv_type),
 355                            yuv_color_space,
 356                            source_width, source_height,
 357                            rgb_buf, rgb_pitch,
 358                            width, height,
 359                            libyuv::kFilterBilinear);
 360   MOZ_ASSERT(!err);
 361   return;
 362 }
 363
 364 // Scale a frame of YUV to 32 bit ARGB.
 365 void ScaleYCbCrToRGB32_deprecated(const uint8_t* y_buf,
 366                                   const uint8_t* u_buf,
 367                                   const uint8_t* v_buf,
 368                                   uint8_t* rgb_buf,
 369                                   int source_width,
 370                                   int source_height,
 371                                   int width,
 372                                   int height,
 373                                   int y_pitch,
 374                                   int uv_pitch,
 375                                   int rgb_pitch,
 376                                   YUVType yuv_type,
 377                                   Rotate view_rotate,
 378                                   ScaleFilter filter) {
 379   bool has_mmx = supports_mmx();
 380
 381   // 4096 allows 3 buffers to fit in 12k.
 382   // Helps performance on CPU with 16K L1 cache.
 383   // Large enough for 3830x2160 and 30" displays which are 2560x1600.
 384   const int kFilterBufferSize = 4096;
 385   // Disable filtering if the screen is too big (to avoid buffer overflows).
 386   // This should never happen to regular users: they don't have monitors
 387   // wider than 4096 pixels.
 388   // TODO(fbarchard): Allow rotated videos to filter.
 389   if (source_width > kFilterBufferSize || view_rotate)
 390     filter = FILTER_NONE;
 391
 392   unsigned int y_shift = yuv_type == YV12 ? 1 : 0;
 393   // Diagram showing origin and direction of source sampling.
 394   // ->0   4<-
 395   // 7       3
 396   //
 397   // 6       5
 398   // ->1   2<-
 399   // Rotations that start at right side of image.
 400   if ((view_rotate == ROTATE_180) ||
 401       (view_rotate == ROTATE_270) ||
 402       (view_rotate == MIRROR_ROTATE_0) ||
 403       (view_rotate == MIRROR_ROTATE_90)) {
 404     y_buf += source_width - 1;
 405     u_buf += source_width / 2 - 1;
 406     v_buf += source_width / 2 - 1;
 407     source_width = -source_width;
 408   }
 409   // Rotations that start at bottom of image.
 410   if ((view_rotate == ROTATE_90) ||
 411       (view_rotate == ROTATE_180) ||
 412       (view_rotate == MIRROR_ROTATE_90) ||
 413       (view_rotate == MIRROR_ROTATE_180)) {
 414     y_buf += (source_height - 1) * y_pitch;
 415     u_buf += ((source_height >> y_shift) - 1) * uv_pitch;
 416     v_buf += ((source_height >> y_shift) - 1) * uv_pitch;
 417     source_height = -source_height;
 418   }
 419
 420   // Handle zero sized destination.
 421   if (width == 0 || height == 0)
 422     return;
 423   int source_dx = source_width * kFractionMax / width;
 424   int source_dy = source_height * kFractionMax / height;
 425   int source_dx_uv = source_dx;
 426
 427   if ((view_rotate == ROTATE_90) ||
 428       (view_rotate == ROTATE_270)) {
 429     int tmp = height;
 430     height = width;
 431     width = tmp;
 432     tmp = source_height;
 433     source_height = source_width;
 434     source_width = tmp;
 435     int original_dx = source_dx;
 436     int original_dy = source_dy;
 437     source_dx = ((original_dy >> kFractionBits) * y_pitch) << kFractionBits;
 438     source_dx_uv = ((original_dy >> kFractionBits) * uv_pitch) << kFractionBits;
 439     source_dy = original_dx;
 440     if (view_rotate == ROTATE_90) {
 441       y_pitch = -1;
 442       uv_pitch = -1;
 443       source_height = -source_height;
 444     } else {
 445       y_pitch = 1;
 446       uv_pitch = 1;
 447     }
 448   }
 449
 450   // Need padding because FilterRows() will write 1 to 16 extra pixels
 451   // after the end for SSE2 version.
 452   uint8_t yuvbuf[16 + kFilterBufferSize * 3 + 16];
 453   uint8_t* ybuf =
 454       reinterpret_cast<uint8_t*>(reinterpret_cast<uintptr_t>(yuvbuf + 15) & ~15);
 455   uint8_t* ubuf = ybuf + kFilterBufferSize;
 456   uint8_t* vbuf = ubuf + kFilterBufferSize;
 457   // TODO(fbarchard): Fixed point math is off by 1 on negatives.
 458   int yscale_fixed = (source_height << kFractionBits) / height;
 459
 460   // TODO(fbarchard): Split this into separate function for better efficiency.
 461   for (int y = 0; y < height; ++y) {
 462     uint8_t* dest_pixel = rgb_buf + y * rgb_pitch;
 463     int source_y_subpixel = (y * yscale_fixed);
 464     if (yscale_fixed >= (kFractionMax * 2)) {
 465       source_y_subpixel += kFractionMax / 2;  // For 1/2 or less, center filter.
 466     }
 467     int source_y = source_y_subpixel >> kFractionBits;
 468
 469     const uint8_t* y0_ptr = y_buf + source_y * y_pitch;
 470     const uint8_t* y1_ptr = y0_ptr + y_pitch;
 471
 472     const uint8_t* u0_ptr = u_buf + (source_y >> y_shift) * uv_pitch;
 473     const uint8_t* u1_ptr = u0_ptr + uv_pitch;
 474     const uint8_t* v0_ptr = v_buf + (source_y >> y_shift) * uv_pitch;
 475     const uint8_t* v1_ptr = v0_ptr + uv_pitch;
 476
 477     // vertical scaler uses 16.8 fixed point
 478     int source_y_fraction = (source_y_subpixel & kFractionMask) >> 8;
 479     int source_uv_fraction =
 480         ((source_y_subpixel >> y_shift) & kFractionMask) >> 8;
 481
 482     const uint8_t* y_ptr = y0_ptr;
 483     const uint8_t* u_ptr = u0_ptr;
 484     const uint8_t* v_ptr = v0_ptr;
 485     // Apply vertical filtering if necessary.
 486     // TODO(fbarchard): Remove memcpy when not necessary.
 487     if (filter & mozilla::gfx::FILTER_BILINEAR_V) {
 488       if (yscale_fixed != kFractionMax &&
 489           source_y_fraction && ((source_y + 1) < source_height)) {
 490         FilterRows(ybuf, y0_ptr, y1_ptr, source_width, source_y_fraction);
 491       } else {
 492         memcpy(ybuf, y0_ptr, source_width);
 493       }
 494       y_ptr = ybuf;
 495       ybuf[source_width] = ybuf[source_width-1];
 496       int uv_source_width = (source_width + 1) / 2;
 497       if (yscale_fixed != kFractionMax &&
 498           source_uv_fraction &&
 499           (((source_y >> y_shift) + 1) < (source_height >> y_shift))) {
 500         FilterRows(ubuf, u0_ptr, u1_ptr, uv_source_width, source_uv_fraction);
 501         FilterRows(vbuf, v0_ptr, v1_ptr, uv_source_width, source_uv_fraction);
 502       } else {
 503         memcpy(ubuf, u0_ptr, uv_source_width);
 504         memcpy(vbuf, v0_ptr, uv_source_width);
 505       }
 506       u_ptr = ubuf;
 507       v_ptr = vbuf;
 508       ubuf[uv_source_width] = ubuf[uv_source_width - 1];
 509       vbuf[uv_source_width] = vbuf[uv_source_width - 1];
 510     }
 511     if (source_dx == kFractionMax) {  // Not scaled
 512       FastConvertYUVToRGB32Row(y_ptr, u_ptr, v_ptr,
 513                                dest_pixel, width);
 514     } else if (filter & FILTER_BILINEAR_H) {
 515         LinearScaleYUVToRGB32Row(y_ptr, u_ptr, v_ptr,
 516                                  dest_pixel, width, source_dx);
 517     } else {
 518 // Specialized scalers and rotation.
 519 #if defined(MOZILLA_MAY_SUPPORT_SSE) && defined(_MSC_VER) && defined(_M_IX86) && !defined(__clang__)
 520       if(mozilla::supports_sse()) {
 521         if (width == (source_width * 2)) {
 522           DoubleYUVToRGB32Row_SSE(y_ptr, u_ptr, v_ptr,
 523                                   dest_pixel, width);
 524         } else if ((source_dx & kFractionMask) == 0) {
 525           // Scaling by integer scale factor. ie half.
 526           ConvertYUVToRGB32Row_SSE(y_ptr, u_ptr, v_ptr,
 527                                    dest_pixel, width,
 528                                    source_dx >> kFractionBits);
 529         } else if (source_dx_uv == source_dx) {  // Not rotated.
 530           ScaleYUVToRGB32Row(y_ptr, u_ptr, v_ptr,
 531                              dest_pixel, width, source_dx);
 532         } else {
 533           RotateConvertYUVToRGB32Row_SSE(y_ptr, u_ptr, v_ptr,
 534                                          dest_pixel, width,
 535                                          source_dx >> kFractionBits,
 536                                          source_dx_uv >> kFractionBits);
 537         }
 538       }
 539       else {
 540         ScaleYUVToRGB32Row_C(y_ptr, u_ptr, v_ptr,
 541                              dest_pixel, width, source_dx);
 542       }
 543 #else
 544       (void)source_dx_uv;
 545       ScaleYUVToRGB32Row(y_ptr, u_ptr, v_ptr,
 546                          dest_pixel, width, source_dx);
 547 #endif
 548     }
 549   }
 550   // MMX used for FastConvertYUVToRGB32Row and FilterRows requires emms.
 551   if (has_mmx)
 552     EMMS();
 553 }
 554 void ConvertI420AlphaToARGB32(const uint8_t* y_buf,
 555                               const uint8_t* u_buf,
 556                               const uint8_t* v_buf,
 557                               const uint8_t* a_buf,
 558                               uint8_t* argb_buf,
 559                               int pic_width,
 560                               int pic_height,
 561                               int ya_pitch,
 562                               int uv_pitch,
 563                               int argb_pitch) {
 564
 565   // The downstream graphics stack expects an attenuated input, hence why the
 566   // attenuation parameter is set.
 567   DebugOnly<int> err = libyuv::I420AlphaToARGB(y_buf, ya_pitch,
 568                                                u_buf, uv_pitch,
 569                                                v_buf, uv_pitch,
 570                                                a_buf, ya_pitch,
 571                                                argb_buf, argb_pitch,
 572                                                pic_width, pic_height, 1);
 573   MOZ_ASSERT(!err);
 574 }
 575
 576 } // namespace gfx
 577 } // namespace mozilla