libwebp-0.6.0-rc1

third_party/libwebp/dsp/enc.c

Index: third_party/libwebp/dsp/enc.c
diff --git a/third_party/libwebp/dsp/enc.c b/third_party/libwebp/dsp/enc.c
index db0e9e70ae74ffa3c3f92c2c93809b36e29c1583..f31bc6de1852458c0c233a09b7499b0f588d9129 100644
--- a/third_party/libwebp/dsp/enc.c
+++ b/third_party/libwebp/dsp/enc.c
@@ -15,7 +15,7 @@
 #include <stdlib.h>  // for abs()
 
 #include "./dsp.h"
-#include "../enc/vp8enci.h"
+#include "../enc/vp8i_enc.h"
 
 static WEBP_INLINE uint8_t clip_8b(int v) {
   return (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
@@ -551,6 +551,20 @@ static int SSE4x4(const uint8_t* a, const uint8_t* b) {
   return GetSSE(a, b, 4, 4);
 }
 
+static void Mean16x4(const uint8_t* ref, uint32_t dc[4]) {
+  int k, x, y;
+  for (k = 0; k < 4; ++k) {
+    uint32_t avg = 0;
+    for (y = 0; y < 4; ++y) {
+      for (x = 0; x < 4; ++x) {
+        avg += ref[x + y * BPS];
+      }
+    }
+    dc[k] = avg;
+    ref += 4;   // go to next 4x4 block.
+  }
+}
+
 //------------------------------------------------------------------------------
 // Texture distortion
 //
@@ -656,32 +670,6 @@ static int Quantize2Blocks(int16_t in[32], int16_t out[32],
   return nz;
 }
 
-static int QuantizeBlockWHT(int16_t in[16], int16_t out[16],
-                            const VP8Matrix* const mtx) {
-  int n, last = -1;
-  for (n = 0; n < 16; ++n) {
-    const int j = kZigzag[n];
-    const int sign = (in[j] < 0);
-    const uint32_t coeff = sign ? -in[j] : in[j];
-    assert(mtx->sharpen_[j] == 0);
-    if (coeff > mtx->zthresh_[j]) {
-      const uint32_t Q = mtx->q_[j];
-      const uint32_t iQ = mtx->iq_[j];
-      const uint32_t B = mtx->bias_[j];
-      int level = QUANTDIV(coeff, iQ, B);
-      if (level > MAX_LEVEL) level = MAX_LEVEL;
-      if (sign) level = -level;
-      in[j] = level * (int)Q;
-      out[n] = level;
-      if (level) last = n;
-    } else {
-      out[n] = 0;
-      in[j] = 0;
-    }
-  }
-  return (last >= 0);
-}
-
 //------------------------------------------------------------------------------
 // Block copy
 
@@ -703,11 +691,51 @@ static void Copy16x8(const uint8_t* src, uint8_t* dst) {
 }
 
 //------------------------------------------------------------------------------
+// SSIM / PSNR
 
-static void SSIMAccumulateClipped(const uint8_t* src1, int stride1,
-                                  const uint8_t* src2, int stride2,
-                                  int xo, int yo, int W, int H,
-                                  VP8DistoStats* const stats) {
+// hat-shaped filter. Sum of coefficients is equal to 16.
+static const uint32_t kWeight[2 * VP8_SSIM_KERNEL + 1] = {
+  1, 2, 3, 4, 3, 2, 1
+};
+static const uint32_t kWeightSum = 16 * 16;   // sum{kWeight}^2
+
+static WEBP_INLINE double SSIMCalculation(
+    const VP8DistoStats* const stats, uint32_t N  /*num samples*/) {
+  const uint32_t w2 =  N * N;
+  const uint32_t C1 = 20 * w2;
+  const uint32_t C2 = 60 * w2;
+  const uint32_t C3 = 8 * 8 * w2;   // 'dark' limit ~= 6
+  const uint64_t xmxm = (uint64_t)stats->xm * stats->xm;
+  const uint64_t ymym = (uint64_t)stats->ym * stats->ym;
+  if (xmxm + ymym >= C3) {
+    const int64_t xmym = (int64_t)stats->xm * stats->ym;
+    const int64_t sxy = (int64_t)stats->xym * N - xmym;    // can be negative
+    const uint64_t sxx = (uint64_t)stats->xxm * N - xmxm;
+    const uint64_t syy = (uint64_t)stats->yym * N - ymym;
+    // we descale by 8 to prevent overflow during the fnum/fden multiply.
+    const uint64_t num_S = (2 * (uint64_t)(sxy < 0 ? 0 : sxy) + C2) >> 8;
+    const uint64_t den_S = (sxx + syy + C2) >> 8;
+    const uint64_t fnum = (2 * xmym + C1) * num_S;
+    const uint64_t fden = (xmxm + ymym + C1) * den_S;
+    const double r = (double)fnum / fden;
+    assert(r >= 0. && r <= 1.0);
+    return r;
+  }
+  return 1.;   // area is too dark to contribute meaningfully
+}
+
+double VP8SSIMFromStats(const VP8DistoStats* const stats) {
+  return SSIMCalculation(stats, kWeightSum);
+}
+
+double VP8SSIMFromStatsClipped(const VP8DistoStats* const stats) {
+  return SSIMCalculation(stats, stats->w);
+}
+
+static double SSIMGetClipped_C(const uint8_t* src1, int stride1,
+                               const uint8_t* src2, int stride2,
+                               int xo, int yo, int W, int H) {
+  VP8DistoStats stats = { 0, 0, 0, 0, 0, 0 };
   const int ymin = (yo - VP8_SSIM_KERNEL < 0) ? 0 : yo - VP8_SSIM_KERNEL;
   const int ymax = (yo + VP8_SSIM_KERNEL > H - 1) ? H - 1
                                                   : yo + VP8_SSIM_KERNEL;
@@ -719,38 +747,61 @@ static void SSIMAccumulateClipped(const uint8_t* src1, int stride1,
   src2 += ymin * stride2;
   for (y = ymin; y <= ymax; ++y, src1 += stride1, src2 += stride2) {
     for (x = xmin; x <= xmax; ++x) {
-      const int s1 = src1[x];
-      const int s2 = src2[x];
-      stats->w   += 1;
-      stats->xm  += s1;
-      stats->ym  += s2;
-      stats->xxm += s1 * s1;
-      stats->xym += s1 * s2;
-      stats->yym += s2 * s2;
+      const uint32_t w = kWeight[VP8_SSIM_KERNEL + x - xo]
+                       * kWeight[VP8_SSIM_KERNEL + y - yo];
+      const uint32_t s1 = src1[x];
+      const uint32_t s2 = src2[x];
+      stats.w   += w;
+      stats.xm  += w * s1;
+      stats.ym  += w * s2;
+      stats.xxm += w * s1 * s1;
+      stats.xym += w * s1 * s2;
+      stats.yym += w * s2 * s2;
     }
   }
+  return VP8SSIMFromStatsClipped(&stats);
 }
 
-static void SSIMAccumulate(const uint8_t* src1, int stride1,
-                           const uint8_t* src2, int stride2,
-                           VP8DistoStats* const stats) {
+static double SSIMGet_C(const uint8_t* src1, int stride1,
+                        const uint8_t* src2, int stride2) {
+  VP8DistoStats stats = { 0, 0, 0, 0, 0, 0 };
   int x, y;
   for (y = 0; y <= 2 * VP8_SSIM_KERNEL; ++y, src1 += stride1, src2 += stride2) {
     for (x = 0; x <= 2 * VP8_SSIM_KERNEL; ++x) {
-      const int s1 = src1[x];
-      const int s2 = src2[x];
-      stats->w   += 1;
-      stats->xm  += s1;
-      stats->ym  += s2;
-      stats->xxm += s1 * s1;
-      stats->xym += s1 * s2;
-      stats->yym += s2 * s2;
+      const uint32_t w = kWeight[x] * kWeight[y];
+      const uint32_t s1 = src1[x];
+      const uint32_t s2 = src2[x];
+      stats.xm  += w * s1;
+      stats.ym  += w * s2;
+      stats.xxm += w * s1 * s1;
+      stats.xym += w * s1 * s2;
+      stats.yym += w * s2 * s2;
     }
   }
+  return VP8SSIMFromStats(&stats);
+}
+
+//------------------------------------------------------------------------------
+
+static uint32_t AccumulateSSE(const uint8_t* src1,
+                              const uint8_t* src2, int len) {
+  int i;
+  uint32_t sse2 = 0;
+  assert(len <= 65535);  // to ensure that accumulation fits within uint32_t
+  for (i = 0; i < len; ++i) {
+    const int32_t diff = src1[i] - src2[i];
+    sse2 += diff * diff;
+  }
+  return sse2;
 }
 
-VP8SSIMAccumulateFunc VP8SSIMAccumulate;
-VP8SSIMAccumulateClippedFunc VP8SSIMAccumulateClipped;
+//------------------------------------------------------------------------------
+
+VP8SSIMGetFunc VP8SSIMGet;
+VP8SSIMGetClippedFunc VP8SSIMGetClipped;
+VP8AccumulateSSEFunc VP8AccumulateSSE;
+
+extern void VP8SSIMDspInitSSE2(void);
 
 static volatile VP8CPUInfo ssim_last_cpuinfo_used =
     (VP8CPUInfo)&ssim_last_cpuinfo_used;
@@ -758,8 +809,17 @@ static volatile VP8CPUInfo ssim_last_cpuinfo_used =
 WEBP_TSAN_IGNORE_FUNCTION void VP8SSIMDspInit(void) {
   if (ssim_last_cpuinfo_used == VP8GetCPUInfo) return;
 
-  VP8SSIMAccumulate = SSIMAccumulate;
-  VP8SSIMAccumulateClipped = SSIMAccumulateClipped;
+  VP8SSIMGetClipped = SSIMGetClipped_C;
+  VP8SSIMGet = SSIMGet_C;
+
+  VP8AccumulateSSE = AccumulateSSE;
+  if (VP8GetCPUInfo != NULL) {
+#if defined(WEBP_USE_SSE2)
+    if (VP8GetCPUInfo(kSSE2)) {
+      VP8SSIMDspInitSSE2();
+    }
+#endif
+  }
 
   ssim_last_cpuinfo_used = VP8GetCPUInfo;
 }
@@ -783,6 +843,7 @@ VP8Metric VP8SSE16x8;
 VP8Metric VP8SSE4x4;
 VP8WMetric VP8TDisto4x4;
 VP8WMetric VP8TDisto16x16;
+VP8MeanMetric VP8Mean16x4;
 VP8QuantizeBlock VP8EncQuantizeBlock;
 VP8Quantize2Blocks VP8EncQuantize2Blocks;
 VP8QuantizeBlockWHT VP8EncQuantizeBlockWHT;
@@ -795,6 +856,7 @@ extern void VP8EncDspInitAVX2(void);
 extern void VP8EncDspInitNEON(void);
 extern void VP8EncDspInitMIPS32(void);
 extern void VP8EncDspInitMIPSdspR2(void);
+extern void VP8EncDspInitMSA(void);
 
 static volatile VP8CPUInfo enc_last_cpuinfo_used =
     (VP8CPUInfo)&enc_last_cpuinfo_used;
@@ -820,9 +882,10 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8EncDspInit(void) {
   VP8SSE4x4 = SSE4x4;
   VP8TDisto4x4 = Disto4x4;
   VP8TDisto16x16 = Disto16x16;
+  VP8Mean16x4 = Mean16x4;
   VP8EncQuantizeBlock = QuantizeBlock;
   VP8EncQuantize2Blocks = Quantize2Blocks;
-  VP8EncQuantizeBlockWHT = QuantizeBlockWHT;
+  VP8EncQuantizeBlockWHT = QuantizeBlock;
   VP8Copy4x4 = Copy4x4;
   VP8Copy16x8 = Copy16x8;
 
@@ -858,6 +921,11 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8EncDspInit(void) {
       VP8EncDspInitMIPSdspR2();
     }
 #endif
+#if defined(WEBP_USE_MSA)
+    if (VP8GetCPUInfo(kMSA)) {
+      VP8EncDspInitMSA();
+    }
+#endif
   }
   enc_last_cpuinfo_used = VP8GetCPUInfo;
 }