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      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 (at) google.com (Somnath Banerjee)
     13 
     14 #include "./dsp.h"
     15 #include "./yuv.h"
     16 
     17 #if defined(__cplusplus) || defined(c_plusplus)
     18 extern "C" {
     19 #endif
     20 
     21 //------------------------------------------------------------------------------
     22 // Fancy upsampler
     23 
     24 #ifdef FANCY_UPSAMPLING
     25 
     26 // Fancy upsampling functions to convert YUV to RGB
     27 WebPUpsampleLinePairFunc WebPUpsamplers[MODE_LAST];
     28 
     29 // Given samples laid out in a square as:
     30 //  [a b]
     31 //  [c d]
     32 // we interpolate u/v as:
     33 //  ([9*a + 3*b + 3*c +   d    3*a + 9*b + 3*c +   d] + [8 8]) / 16
     34 //  ([3*a +   b + 9*c + 3*d      a + 3*b + 3*c + 9*d]   [8 8]) / 16
     35 
     36 // We process u and v together stashed into 32bit (16bit each).
     37 #define LOAD_UV(u, v) ((u) | ((v) << 16))
     38 
     39 #define UPSAMPLE_FUNC(FUNC_NAME, FUNC, XSTEP)                                  \
     40 static void FUNC_NAME(const uint8_t* top_y, const uint8_t* bottom_y,           \
     41                       const uint8_t* top_u, const uint8_t* top_v,              \
     42                       const uint8_t* cur_u, const uint8_t* cur_v,              \
     43                       uint8_t* top_dst, uint8_t* bottom_dst, int len) {        \
     44   int x;                                                                       \
     45   const int last_pixel_pair = (len - 1) >> 1;                                  \
     46   uint32_t tl_uv = LOAD_UV(top_u[0], top_v[0]);   /* top-left sample */        \
     47   uint32_t l_uv  = LOAD_UV(cur_u[0], cur_v[0]);   /* left-sample */            \
     48   if (top_y) {                                                                 \
     49     const uint32_t uv0 = (3 * tl_uv + l_uv + 0x00020002u) >> 2;                \
     50     FUNC(top_y[0], uv0 & 0xff, (uv0 >> 16), top_dst);                          \
     51   }                                                                            \
     52   if (bottom_y) {                                                              \
     53     const uint32_t uv0 = (3 * l_uv + tl_uv + 0x00020002u) >> 2;                \
     54     FUNC(bottom_y[0], uv0 & 0xff, (uv0 >> 16), bottom_dst);                    \
     55   }                                                                            \
     56   for (x = 1; x <= last_pixel_pair; ++x) {                                     \
     57     const uint32_t t_uv = LOAD_UV(top_u[x], top_v[x]);  /* top sample */       \
     58     const uint32_t uv   = LOAD_UV(cur_u[x], cur_v[x]);  /* sample */           \
     59     /* precompute invariant values associated with first and second diagonals*/\
     60     const uint32_t avg = tl_uv + t_uv + l_uv + uv + 0x00080008u;               \
     61     const uint32_t diag_12 = (avg + 2 * (t_uv + l_uv)) >> 3;                   \
     62     const uint32_t diag_03 = (avg + 2 * (tl_uv + uv)) >> 3;                    \
     63     if (top_y) {                                                               \
     64       const uint32_t uv0 = (diag_12 + tl_uv) >> 1;                             \
     65       const uint32_t uv1 = (diag_03 + t_uv) >> 1;                              \
     66       FUNC(top_y[2 * x - 1], uv0 & 0xff, (uv0 >> 16),                          \
     67            top_dst + (2 * x - 1) * XSTEP);                                     \
     68       FUNC(top_y[2 * x - 0], uv1 & 0xff, (uv1 >> 16),                          \
     69            top_dst + (2 * x - 0) * XSTEP);                                     \
     70     }                                                                          \
     71     if (bottom_y) {                                                            \
     72       const uint32_t uv0 = (diag_03 + l_uv) >> 1;                              \
     73       const uint32_t uv1 = (diag_12 + uv) >> 1;                                \
     74       FUNC(bottom_y[2 * x - 1], uv0 & 0xff, (uv0 >> 16),                       \
     75            bottom_dst + (2 * x - 1) * XSTEP);                                  \
     76       FUNC(bottom_y[2 * x + 0], uv1 & 0xff, (uv1 >> 16),                       \
     77            bottom_dst + (2 * x + 0) * XSTEP);                                  \
     78     }                                                                          \
     79     tl_uv = t_uv;                                                              \
     80     l_uv = uv;                                                                 \
     81   }                                                                            \
     82   if (!(len & 1)) {                                                            \
     83     if (top_y) {                                                               \
     84       const uint32_t uv0 = (3 * tl_uv + l_uv + 0x00020002u) >> 2;              \
     85       FUNC(top_y[len - 1], uv0 & 0xff, (uv0 >> 16),                            \
     86            top_dst + (len - 1) * XSTEP);                                       \
     87     }                                                                          \
     88     if (bottom_y) {                                                            \
     89       const uint32_t uv0 = (3 * l_uv + tl_uv + 0x00020002u) >> 2;              \
     90       FUNC(bottom_y[len - 1], uv0 & 0xff, (uv0 >> 16),                         \
     91            bottom_dst + (len - 1) * XSTEP);                                    \
     92     }                                                                          \
     93   }                                                                            \
     94 }
     95 
     96 // All variants implemented.
     97 UPSAMPLE_FUNC(UpsampleRgbLinePair,  VP8YuvToRgb,  3)
     98 UPSAMPLE_FUNC(UpsampleBgrLinePair,  VP8YuvToBgr,  3)
     99 UPSAMPLE_FUNC(UpsampleRgbaLinePair, VP8YuvToRgba, 4)
    100 UPSAMPLE_FUNC(UpsampleBgraLinePair, VP8YuvToBgra, 4)
    101 UPSAMPLE_FUNC(UpsampleArgbLinePair, VP8YuvToArgb, 4)
    102 UPSAMPLE_FUNC(UpsampleRgba4444LinePair, VP8YuvToRgba4444, 2)
    103 UPSAMPLE_FUNC(UpsampleRgb565LinePair,  VP8YuvToRgb565,  2)
    104 
    105 #undef LOAD_UV
    106 #undef UPSAMPLE_FUNC
    107 
    108 #endif  // FANCY_UPSAMPLING
    109 
    110 //------------------------------------------------------------------------------
    111 // simple point-sampling
    112 
    113 #define SAMPLE_FUNC(FUNC_NAME, FUNC, XSTEP)                                    \
    114 static void FUNC_NAME(const uint8_t* top_y, const uint8_t* bottom_y,           \
    115                       const uint8_t* u, const uint8_t* v,                      \
    116                       uint8_t* top_dst, uint8_t* bottom_dst, int len) {        \
    117   int i;                                                                       \
    118   for (i = 0; i < len - 1; i += 2) {                                           \
    119     FUNC(top_y[0], u[0], v[0], top_dst);                                       \
    120     FUNC(top_y[1], u[0], v[0], top_dst + XSTEP);                               \
    121     FUNC(bottom_y[0], u[0], v[0], bottom_dst);                                 \
    122     FUNC(bottom_y[1], u[0], v[0], bottom_dst + XSTEP);                         \
    123     top_y += 2;                                                                \
    124     bottom_y += 2;                                                             \
    125     u++;                                                                       \
    126     v++;                                                                       \
    127     top_dst += 2 * XSTEP;                                                      \
    128     bottom_dst += 2 * XSTEP;                                                   \
    129   }                                                                            \
    130   if (i == len - 1) {    /* last one */                                        \
    131     FUNC(top_y[0], u[0], v[0], top_dst);                                       \
    132     FUNC(bottom_y[0], u[0], v[0], bottom_dst);                                 \
    133   }                                                                            \
    134 }
    135 
    136 // All variants implemented.
    137 SAMPLE_FUNC(SampleRgbLinePair,      VP8YuvToRgb,  3)
    138 SAMPLE_FUNC(SampleBgrLinePair,      VP8YuvToBgr,  3)
    139 SAMPLE_FUNC(SampleRgbaLinePair,     VP8YuvToRgba, 4)
    140 SAMPLE_FUNC(SampleBgraLinePair,     VP8YuvToBgra, 4)
    141 SAMPLE_FUNC(SampleArgbLinePair,     VP8YuvToArgb, 4)
    142 SAMPLE_FUNC(SampleRgba4444LinePair, VP8YuvToRgba4444, 2)
    143 SAMPLE_FUNC(SampleRgb565LinePair,   VP8YuvToRgb565, 2)
    144 
    145 #undef SAMPLE_FUNC
    146 
    147 const WebPSampleLinePairFunc WebPSamplers[MODE_LAST] = {
    148   SampleRgbLinePair,       // MODE_RGB
    149   SampleRgbaLinePair,      // MODE_RGBA
    150   SampleBgrLinePair,       // MODE_BGR
    151   SampleBgraLinePair,      // MODE_BGRA
    152   SampleArgbLinePair,      // MODE_ARGB
    153   SampleRgba4444LinePair,  // MODE_RGBA_4444
    154   SampleRgb565LinePair,    // MODE_RGB_565
    155   SampleRgbaLinePair,      // MODE_rgbA
    156   SampleBgraLinePair,      // MODE_bgrA
    157   SampleArgbLinePair,      // MODE_Argb
    158   SampleRgba4444LinePair   // MODE_rgbA_4444
    159 };
    160 
    161 //------------------------------------------------------------------------------
    162 
    163 #if !defined(FANCY_UPSAMPLING)
    164 #define DUAL_SAMPLE_FUNC(FUNC_NAME, FUNC)                                      \
    165 static void FUNC_NAME(const uint8_t* top_y, const uint8_t* bot_y,              \
    166                       const uint8_t* top_u, const uint8_t* top_v,              \
    167                       const uint8_t* bot_u, const uint8_t* bot_v,              \
    168                       uint8_t* top_dst, uint8_t* bot_dst, int len) {           \
    169   const int half_len = len >> 1;                                               \
    170   int x;                                                                       \
    171   if (top_dst != NULL) {                                                       \
    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 
    367 #if defined(__cplusplus) || defined(c_plusplus)
    368 }    // extern "C"
    369 #endif
    370