github.com/cellofellow/gopkg@v0.0.0-20140722061823-eec0544a62ad/image/webp/libwebp/src/dsp/upsampling.c (about)

     1  // Copyright 2011 Google Inc. All Rights Reserved.
     2  //
     3  // Use of this source code is governed by a BSD-style license
     4  // that can be found in the COPYING file in the root of the source
     5  // tree. An additional intellectual property rights grant can be found
     6  // in the file PATENTS. All contributing project authors may
     7  // be found in the AUTHORS file in the root of the source tree.
     8  // -----------------------------------------------------------------------------
     9  //
    10  // YUV to RGB upsampling functions.
    11  //
    12  // Author: somnath@google.com (Somnath Banerjee)
    13  
    14  #include "./dsp.h"
    15  #include "./yuv.h"
    16  
    17  #include <assert.h>
    18  
    19  //------------------------------------------------------------------------------
    20  // Fancy upsampler
    21  
    22  #ifdef FANCY_UPSAMPLING
    23  
    24  // Fancy upsampling functions to convert YUV to RGB
    25  WebPUpsampleLinePairFunc WebPUpsamplers[MODE_LAST];
    26  
    27  // Given samples laid out in a square as:
    28  //  [a b]
    29  //  [c d]
    30  // we interpolate u/v as:
    31  //  ([9*a + 3*b + 3*c +   d    3*a + 9*b + 3*c +   d] + [8 8]) / 16
    32  //  ([3*a +   b + 9*c + 3*d      a + 3*b + 3*c + 9*d]   [8 8]) / 16
    33  
    34  // We process u and v together stashed into 32bit (16bit each).
    35  #define LOAD_UV(u, v) ((u) | ((v) << 16))
    36  
    37  #define UPSAMPLE_FUNC(FUNC_NAME, FUNC, XSTEP)                                  \
    38  static void FUNC_NAME(const uint8_t* top_y, const uint8_t* bottom_y,           \
    39                        const uint8_t* top_u, const uint8_t* top_v,              \
    40                        const uint8_t* cur_u, const uint8_t* cur_v,              \
    41                        uint8_t* top_dst, uint8_t* bottom_dst, int len) {        \
    42    int x;                                                                       \
    43    const int last_pixel_pair = (len - 1) >> 1;                                  \
    44    uint32_t tl_uv = LOAD_UV(top_u[0], top_v[0]);   /* top-left sample */        \
    45    uint32_t l_uv  = LOAD_UV(cur_u[0], cur_v[0]);   /* left-sample */            \
    46    assert(top_y != NULL);                                                       \
    47    {                                                                            \
    48      const uint32_t uv0 = (3 * tl_uv + l_uv + 0x00020002u) >> 2;                \
    49      FUNC(top_y[0], uv0 & 0xff, (uv0 >> 16), top_dst);                          \
    50    }                                                                            \
    51    if (bottom_y != NULL) {                                                      \
    52      const uint32_t uv0 = (3 * l_uv + tl_uv + 0x00020002u) >> 2;                \
    53      FUNC(bottom_y[0], uv0 & 0xff, (uv0 >> 16), bottom_dst);                    \
    54    }                                                                            \
    55    for (x = 1; x <= last_pixel_pair; ++x) {                                     \
    56      const uint32_t t_uv = LOAD_UV(top_u[x], top_v[x]);  /* top sample */       \
    57      const uint32_t uv   = LOAD_UV(cur_u[x], cur_v[x]);  /* sample */           \
    58      /* precompute invariant values associated with first and second diagonals*/\
    59      const uint32_t avg = tl_uv + t_uv + l_uv + uv + 0x00080008u;               \
    60      const uint32_t diag_12 = (avg + 2 * (t_uv + l_uv)) >> 3;                   \
    61      const uint32_t diag_03 = (avg + 2 * (tl_uv + uv)) >> 3;                    \
    62      {                                                                          \
    63        const uint32_t uv0 = (diag_12 + tl_uv) >> 1;                             \
    64        const uint32_t uv1 = (diag_03 + t_uv) >> 1;                              \
    65        FUNC(top_y[2 * x - 1], uv0 & 0xff, (uv0 >> 16),                          \
    66             top_dst + (2 * x - 1) * XSTEP);                                     \
    67        FUNC(top_y[2 * x - 0], uv1 & 0xff, (uv1 >> 16),                          \
    68             top_dst + (2 * x - 0) * XSTEP);                                     \
    69      }                                                                          \
    70      if (bottom_y != NULL) {                                                    \
    71        const uint32_t uv0 = (diag_03 + l_uv) >> 1;                              \
    72        const uint32_t uv1 = (diag_12 + uv) >> 1;                                \
    73        FUNC(bottom_y[2 * x - 1], uv0 & 0xff, (uv0 >> 16),                       \
    74             bottom_dst + (2 * x - 1) * XSTEP);                                  \
    75        FUNC(bottom_y[2 * x + 0], uv1 & 0xff, (uv1 >> 16),                       \
    76             bottom_dst + (2 * x + 0) * XSTEP);                                  \
    77      }                                                                          \
    78      tl_uv = t_uv;                                                              \
    79      l_uv = uv;                                                                 \
    80    }                                                                            \
    81    if (!(len & 1)) {                                                            \
    82      {                                                                          \
    83        const uint32_t uv0 = (3 * tl_uv + l_uv + 0x00020002u) >> 2;              \
    84        FUNC(top_y[len - 1], uv0 & 0xff, (uv0 >> 16),                            \
    85             top_dst + (len - 1) * XSTEP);                                       \
    86      }                                                                          \
    87      if (bottom_y != NULL) {                                                    \
    88        const uint32_t uv0 = (3 * l_uv + tl_uv + 0x00020002u) >> 2;              \
    89        FUNC(bottom_y[len - 1], uv0 & 0xff, (uv0 >> 16),                         \
    90             bottom_dst + (len - 1) * XSTEP);                                    \
    91      }                                                                          \
    92    }                                                                            \
    93  }
    94  
    95  // All variants implemented.
    96  UPSAMPLE_FUNC(UpsampleRgbLinePair,  VP8YuvToRgb,  3)
    97  UPSAMPLE_FUNC(UpsampleBgrLinePair,  VP8YuvToBgr,  3)
    98  UPSAMPLE_FUNC(UpsampleRgbaLinePair, VP8YuvToRgba, 4)
    99  UPSAMPLE_FUNC(UpsampleBgraLinePair, VP8YuvToBgra, 4)
   100  UPSAMPLE_FUNC(UpsampleArgbLinePair, VP8YuvToArgb, 4)
   101  UPSAMPLE_FUNC(UpsampleRgba4444LinePair, VP8YuvToRgba4444, 2)
   102  UPSAMPLE_FUNC(UpsampleRgb565LinePair,  VP8YuvToRgb565,  2)
   103  
   104  #undef LOAD_UV
   105  #undef UPSAMPLE_FUNC
   106  
   107  #endif  // FANCY_UPSAMPLING
   108  
   109  //------------------------------------------------------------------------------
   110  // simple point-sampling
   111  
   112  #define SAMPLE_FUNC(FUNC_NAME, FUNC, XSTEP)                                    \
   113  static void FUNC_NAME(const uint8_t* top_y, const uint8_t* bottom_y,           \
   114                        const uint8_t* u, const uint8_t* v,                      \
   115                        uint8_t* top_dst, uint8_t* bottom_dst, int len) {        \
   116    int i;                                                                       \
   117    for (i = 0; i < len - 1; i += 2) {                                           \
   118      FUNC(top_y[0], u[0], v[0], top_dst);                                       \
   119      FUNC(top_y[1], u[0], v[0], top_dst + XSTEP);                               \
   120      FUNC(bottom_y[0], u[0], v[0], bottom_dst);                                 \
   121      FUNC(bottom_y[1], u[0], v[0], bottom_dst + XSTEP);                         \
   122      top_y += 2;                                                                \
   123      bottom_y += 2;                                                             \
   124      u++;                                                                       \
   125      v++;                                                                       \
   126      top_dst += 2 * XSTEP;                                                      \
   127      bottom_dst += 2 * XSTEP;                                                   \
   128    }                                                                            \
   129    if (i == len - 1) {    /* last one */                                        \
   130      FUNC(top_y[0], u[0], v[0], top_dst);                                       \
   131      FUNC(bottom_y[0], u[0], v[0], bottom_dst);                                 \
   132    }                                                                            \
   133  }
   134  
   135  // All variants implemented.
   136  SAMPLE_FUNC(SampleRgbLinePair,      VP8YuvToRgb,  3)
   137  SAMPLE_FUNC(SampleBgrLinePair,      VP8YuvToBgr,  3)
   138  SAMPLE_FUNC(SampleRgbaLinePair,     VP8YuvToRgba, 4)
   139  SAMPLE_FUNC(SampleBgraLinePair,     VP8YuvToBgra, 4)
   140  SAMPLE_FUNC(SampleArgbLinePair,     VP8YuvToArgb, 4)
   141  SAMPLE_FUNC(SampleRgba4444LinePair, VP8YuvToRgba4444, 2)
   142  SAMPLE_FUNC(SampleRgb565LinePair,   VP8YuvToRgb565, 2)
   143  
   144  #undef SAMPLE_FUNC
   145  
   146  const WebPSampleLinePairFunc WebPSamplers[MODE_LAST] = {
   147    SampleRgbLinePair,       // MODE_RGB
   148    SampleRgbaLinePair,      // MODE_RGBA
   149    SampleBgrLinePair,       // MODE_BGR
   150    SampleBgraLinePair,      // MODE_BGRA
   151    SampleArgbLinePair,      // MODE_ARGB
   152    SampleRgba4444LinePair,  // MODE_RGBA_4444
   153    SampleRgb565LinePair,    // MODE_RGB_565
   154    SampleRgbaLinePair,      // MODE_rgbA
   155    SampleBgraLinePair,      // MODE_bgrA
   156    SampleArgbLinePair,      // MODE_Argb
   157    SampleRgba4444LinePair   // MODE_rgbA_4444
   158  };
   159  
   160  //------------------------------------------------------------------------------
   161  
   162  #if !defined(FANCY_UPSAMPLING)
   163  #define DUAL_SAMPLE_FUNC(FUNC_NAME, FUNC)                                      \
   164  static void FUNC_NAME(const uint8_t* top_y, const uint8_t* bot_y,              \
   165                        const uint8_t* top_u, const uint8_t* top_v,              \
   166                        const uint8_t* bot_u, const uint8_t* bot_v,              \
   167                        uint8_t* top_dst, uint8_t* bot_dst, int len) {           \
   168    const int half_len = len >> 1;                                               \
   169    int x;                                                                       \
   170    assert(top_dst != NULL);                                                     \
   171    {                                                                            \
   172      for (x = 0; x < half_len; ++x) {                                           \
   173        FUNC(top_y[2 * x + 0], top_u[x], top_v[x], top_dst + 8 * x + 0);         \
   174        FUNC(top_y[2 * x + 1], top_u[x], top_v[x], top_dst + 8 * x + 4);         \
   175      }                                                                          \
   176      if (len & 1) FUNC(top_y[2 * x + 0], top_u[x], top_v[x], top_dst + 8 * x);  \
   177    }                                                                            \
   178    if (bot_dst != NULL) {                                                       \
   179      for (x = 0; x < half_len; ++x) {                                           \
   180        FUNC(bot_y[2 * x + 0], bot_u[x], bot_v[x], bot_dst + 8 * x + 0);         \
   181        FUNC(bot_y[2 * x + 1], bot_u[x], bot_v[x], bot_dst + 8 * x + 4);         \
   182      }                                                                          \
   183      if (len & 1) FUNC(bot_y[2 * x + 0], bot_u[x], bot_v[x], bot_dst + 8 * x);  \
   184    }                                                                            \
   185  }
   186  
   187  DUAL_SAMPLE_FUNC(DualLineSamplerBGRA, VP8YuvToBgra)
   188  DUAL_SAMPLE_FUNC(DualLineSamplerARGB, VP8YuvToArgb)
   189  #undef DUAL_SAMPLE_FUNC
   190  
   191  #endif  // !FANCY_UPSAMPLING
   192  
   193  WebPUpsampleLinePairFunc WebPGetLinePairConverter(int alpha_is_last) {
   194    WebPInitUpsamplers();
   195    VP8YUVInit();
   196  #ifdef FANCY_UPSAMPLING
   197    return WebPUpsamplers[alpha_is_last ? MODE_BGRA : MODE_ARGB];
   198  #else
   199    return (alpha_is_last ? DualLineSamplerBGRA : DualLineSamplerARGB);
   200  #endif
   201  }
   202  
   203  //------------------------------------------------------------------------------
   204  // YUV444 converter
   205  
   206  #define YUV444_FUNC(FUNC_NAME, FUNC, XSTEP)                                    \
   207  static void FUNC_NAME(const uint8_t* y, const uint8_t* u, const uint8_t* v,    \
   208                        uint8_t* dst, int len) {                                 \
   209    int i;                                                                       \
   210    for (i = 0; i < len; ++i) FUNC(y[i], u[i], v[i], &dst[i * XSTEP]);           \
   211  }
   212  
   213  YUV444_FUNC(Yuv444ToRgb,      VP8YuvToRgb,  3)
   214  YUV444_FUNC(Yuv444ToBgr,      VP8YuvToBgr,  3)
   215  YUV444_FUNC(Yuv444ToRgba,     VP8YuvToRgba, 4)
   216  YUV444_FUNC(Yuv444ToBgra,     VP8YuvToBgra, 4)
   217  YUV444_FUNC(Yuv444ToArgb,     VP8YuvToArgb, 4)
   218  YUV444_FUNC(Yuv444ToRgba4444, VP8YuvToRgba4444, 2)
   219  YUV444_FUNC(Yuv444ToRgb565,   VP8YuvToRgb565, 2)
   220  
   221  #undef YUV444_FUNC
   222  
   223  const WebPYUV444Converter WebPYUV444Converters[MODE_LAST] = {
   224    Yuv444ToRgb,       // MODE_RGB
   225    Yuv444ToRgba,      // MODE_RGBA
   226    Yuv444ToBgr,       // MODE_BGR
   227    Yuv444ToBgra,      // MODE_BGRA
   228    Yuv444ToArgb,      // MODE_ARGB
   229    Yuv444ToRgba4444,  // MODE_RGBA_4444
   230    Yuv444ToRgb565,    // MODE_RGB_565
   231    Yuv444ToRgba,      // MODE_rgbA
   232    Yuv444ToBgra,      // MODE_bgrA
   233    Yuv444ToArgb,      // MODE_Argb
   234    Yuv444ToRgba4444   // MODE_rgbA_4444
   235  };
   236  
   237  //------------------------------------------------------------------------------
   238  // Premultiplied modes
   239  
   240  // non dithered-modes
   241  
   242  // (x * a * 32897) >> 23 is bit-wise equivalent to (int)(x * a / 255.)
   243  // for all 8bit x or a. For bit-wise equivalence to (int)(x * a / 255. + .5),
   244  // one can use instead: (x * a * 65793 + (1 << 23)) >> 24
   245  #if 1     // (int)(x * a / 255.)
   246  #define MULTIPLIER(a)   ((a) * 32897UL)
   247  #define PREMULTIPLY(x, m) (((x) * (m)) >> 23)
   248  #else     // (int)(x * a / 255. + .5)
   249  #define MULTIPLIER(a) ((a) * 65793UL)
   250  #define PREMULTIPLY(x, m) (((x) * (m) + (1UL << 23)) >> 24)
   251  #endif
   252  
   253  static void ApplyAlphaMultiply(uint8_t* rgba, int alpha_first,
   254                                 int w, int h, int stride) {
   255    while (h-- > 0) {
   256      uint8_t* const rgb = rgba + (alpha_first ? 1 : 0);
   257      const uint8_t* const alpha = rgba + (alpha_first ? 0 : 3);
   258      int i;
   259      for (i = 0; i < w; ++i) {
   260        const uint32_t a = alpha[4 * i];
   261        if (a != 0xff) {
   262          const uint32_t mult = MULTIPLIER(a);
   263          rgb[4 * i + 0] = PREMULTIPLY(rgb[4 * i + 0], mult);
   264          rgb[4 * i + 1] = PREMULTIPLY(rgb[4 * i + 1], mult);
   265          rgb[4 * i + 2] = PREMULTIPLY(rgb[4 * i + 2], mult);
   266        }
   267      }
   268      rgba += stride;
   269    }
   270  }
   271  #undef MULTIPLIER
   272  #undef PREMULTIPLY
   273  
   274  // rgbA4444
   275  
   276  #define MULTIPLIER(a)  ((a) * 0x1111)    // 0x1111 ~= (1 << 16) / 15
   277  
   278  static WEBP_INLINE uint8_t dither_hi(uint8_t x) {
   279    return (x & 0xf0) | (x >> 4);
   280  }
   281  
   282  static WEBP_INLINE uint8_t dither_lo(uint8_t x) {
   283    return (x & 0x0f) | (x << 4);
   284  }
   285  
   286  static WEBP_INLINE uint8_t multiply(uint8_t x, uint32_t m) {
   287    return (x * m) >> 16;
   288  }
   289  
   290  static void ApplyAlphaMultiply4444(uint8_t* rgba4444,
   291                                     int w, int h, int stride) {
   292    while (h-- > 0) {
   293      int i;
   294      for (i = 0; i < w; ++i) {
   295        const uint8_t a = (rgba4444[2 * i + 1] & 0x0f);
   296        const uint32_t mult = MULTIPLIER(a);
   297        const uint8_t r = multiply(dither_hi(rgba4444[2 * i + 0]), mult);
   298        const uint8_t g = multiply(dither_lo(rgba4444[2 * i + 0]), mult);
   299        const uint8_t b = multiply(dither_hi(rgba4444[2 * i + 1]), mult);
   300        rgba4444[2 * i + 0] = (r & 0xf0) | ((g >> 4) & 0x0f);
   301        rgba4444[2 * i + 1] = (b & 0xf0) | a;
   302      }
   303      rgba4444 += stride;
   304    }
   305  }
   306  #undef MULTIPLIER
   307  
   308  void (*WebPApplyAlphaMultiply)(uint8_t*, int, int, int, int)
   309      = ApplyAlphaMultiply;
   310  void (*WebPApplyAlphaMultiply4444)(uint8_t*, int, int, int)
   311      = ApplyAlphaMultiply4444;
   312  
   313  //------------------------------------------------------------------------------
   314  // Main call
   315  
   316  void WebPInitUpsamplers(void) {
   317  #ifdef FANCY_UPSAMPLING
   318    WebPUpsamplers[MODE_RGB]       = UpsampleRgbLinePair;
   319    WebPUpsamplers[MODE_RGBA]      = UpsampleRgbaLinePair;
   320    WebPUpsamplers[MODE_BGR]       = UpsampleBgrLinePair;
   321    WebPUpsamplers[MODE_BGRA]      = UpsampleBgraLinePair;
   322    WebPUpsamplers[MODE_ARGB]      = UpsampleArgbLinePair;
   323    WebPUpsamplers[MODE_RGBA_4444] = UpsampleRgba4444LinePair;
   324    WebPUpsamplers[MODE_RGB_565]   = UpsampleRgb565LinePair;
   325  
   326    // If defined, use CPUInfo() to overwrite some pointers with faster versions.
   327    if (VP8GetCPUInfo != NULL) {
   328  #if defined(WEBP_USE_SSE2)
   329      if (VP8GetCPUInfo(kSSE2)) {
   330        WebPInitUpsamplersSSE2();
   331      }
   332  #endif
   333  #if defined(WEBP_USE_NEON)
   334      if (VP8GetCPUInfo(kNEON)) {
   335        WebPInitUpsamplersNEON();
   336      }
   337  #endif
   338    }
   339  #endif  // FANCY_UPSAMPLING
   340  }
   341  
   342  void WebPInitPremultiply(void) {
   343    WebPApplyAlphaMultiply = ApplyAlphaMultiply;
   344    WebPApplyAlphaMultiply4444 = ApplyAlphaMultiply4444;
   345  
   346  #ifdef FANCY_UPSAMPLING
   347    WebPUpsamplers[MODE_rgbA]      = UpsampleRgbaLinePair;
   348    WebPUpsamplers[MODE_bgrA]      = UpsampleBgraLinePair;
   349    WebPUpsamplers[MODE_Argb]      = UpsampleArgbLinePair;
   350    WebPUpsamplers[MODE_rgbA_4444] = UpsampleRgba4444LinePair;
   351  
   352    if (VP8GetCPUInfo != NULL) {
   353  #if defined(WEBP_USE_SSE2)
   354      if (VP8GetCPUInfo(kSSE2)) {
   355        WebPInitPremultiplySSE2();
   356      }
   357  #endif
   358  #if defined(WEBP_USE_NEON)
   359      if (VP8GetCPUInfo(kNEON)) {
   360        WebPInitPremultiplyNEON();
   361      }
   362  #endif
   363    }
   364  #endif  // FANCY_UPSAMPLING
   365  }
   366