libwebp: Sync with upstream 1.2.2

Changes: https://chromium.googlesource.com/webm/libwebp/+/1.2.2/NEWS

1 files changed, 37 insertions, 21 deletions

diff --git a/thirdparty/libwebp/src/enc/quant_enc.c b/thirdparty/libwebp/src/enc/quant_enc.c
index 01eb565c7f..6cede28ab4 100644
--- a/thirdparty/libwebp/src/enc/quant_enc.c
+++ b/thirdparty/libwebp/src/enc/quant_enc.c
@@ -585,6 +585,9 @@ static WEBP_INLINE score_t RDScoreTrellis(int lambda, score_t rate,
   return rate * lambda + RD_DISTO_MULT * distortion;
 }
 
+// Coefficient type.
+enum { TYPE_I16_AC = 0, TYPE_I16_DC = 1, TYPE_CHROMA_A = 2, TYPE_I4_AC = 3 };
+
 static int TrellisQuantizeBlock(const VP8Encoder* const enc,
                                 int16_t in[16], int16_t out[16],
                                 int ctx0, int coeff_type,
@@ -593,7 +596,7 @@ static int TrellisQuantizeBlock(const VP8Encoder* const enc,
   const ProbaArray* const probas = enc->proba_.coeffs_[coeff_type];
   CostArrayPtr const costs =
       (CostArrayPtr)enc->proba_.remapped_costs_[coeff_type];
-  const int first = (coeff_type == 0) ? 1 : 0;
+  const int first = (coeff_type == TYPE_I16_AC) ? 1 : 0;
   Node nodes[16][NUM_NODES];
   ScoreState score_states[2][NUM_NODES];
   ScoreState* ss_cur = &SCORE_STATE(0, MIN_DELTA);
@@ -657,16 +660,17 @@ static int TrellisQuantizeBlock(const VP8Encoder* const enc,
     // test all alternate level values around level0.
     for (m = -MIN_DELTA; m <= MAX_DELTA; ++m) {
       Node* const cur = &NODE(n, m);
-      int level = level0 + m;
+      const int level = level0 + m;
       const int ctx = (level > 2) ? 2 : level;
       const int band = VP8EncBands[n + 1];
       score_t base_score;
-      score_t best_cur_score = MAX_COST;
-      int best_prev = 0;   // default, in case
+      score_t best_cur_score;
+      int best_prev;
+      score_t cost, score;
 
-      ss_cur[m].score = MAX_COST;
       ss_cur[m].costs = costs[n + 1][ctx];
       if (level < 0 || level > thresh_level) {
+        ss_cur[m].score = MAX_COST;
         // Node is dead.
         continue;
       }
@@ -682,18 +686,24 @@ static int TrellisQuantizeBlock(const VP8Encoder* const enc,
       }
 
       // Inspect all possible non-dead predecessors. Retain only the best one.
-      for (p = -MIN_DELTA; p <= MAX_DELTA; ++p) {
+      // The base_score is added to all scores so it is only added for the final
+      // value after the loop.
+      cost = VP8LevelCost(ss_prev[-MIN_DELTA].costs, level);
+      best_cur_score =
+          ss_prev[-MIN_DELTA].score + RDScoreTrellis(lambda, cost, 0);
+      best_prev = -MIN_DELTA;
+      for (p = -MIN_DELTA + 1; p <= MAX_DELTA; ++p) {
         // Dead nodes (with ss_prev[p].score >= MAX_COST) are automatically
         // eliminated since their score can't be better than the current best.
-        const score_t cost = VP8LevelCost(ss_prev[p].costs, level);
+        cost = VP8LevelCost(ss_prev[p].costs, level);
         // Examine node assuming it's a non-terminal one.
-        const score_t score =
-            base_score + ss_prev[p].score + RDScoreTrellis(lambda, cost, 0);
+        score = ss_prev[p].score + RDScoreTrellis(lambda, cost, 0);
         if (score < best_cur_score) {
           best_cur_score = score;
           best_prev = p;
         }
       }
+      best_cur_score += base_score;
       // Store best finding in current node.
       cur->sign = sign;
       cur->level = level;
@@ -701,11 +711,11 @@ static int TrellisQuantizeBlock(const VP8Encoder* const enc,
       ss_cur[m].score = best_cur_score;
 
       // Now, record best terminal node (and thus best entry in the graph).
-      if (level != 0) {
+      if (level != 0 && best_cur_score < best_score) {
         const score_t last_pos_cost =
             (n < 15) ? VP8BitCost(0, probas[band][ctx][0]) : 0;
         const score_t last_pos_score = RDScoreTrellis(lambda, last_pos_cost, 0);
-        const score_t score = best_cur_score + last_pos_score;
+        score = best_cur_score + last_pos_score;
         if (score < best_score) {
           best_score = score;
           best_path[0] = n;                     // best eob position
@@ -717,10 +727,16 @@ static int TrellisQuantizeBlock(const VP8Encoder* const enc,
   }
 
   // Fresh start
-  memset(in + first, 0, (16 - first) * sizeof(*in));
-  memset(out + first, 0, (16 - first) * sizeof(*out));
+  // Beware! We must preserve in[0]/out[0] value for TYPE_I16_AC case.
+  if (coeff_type == TYPE_I16_AC) {
+    memset(in + 1, 0, 15 * sizeof(*in));
+    memset(out + 1, 0, 15 * sizeof(*out));
+  } else {
+    memset(in, 0, 16 * sizeof(*in));
+    memset(out, 0, 16 * sizeof(*out));
+  }
   if (best_path[0] == -1) {
-    return 0;   // skip!
+    return 0;  // skip!
   }
 
   {
@@ -775,9 +791,9 @@ static int ReconstructIntra16(VP8EncIterator* const it,
     for (y = 0, n = 0; y < 4; ++y) {
       for (x = 0; x < 4; ++x, ++n) {
         const int ctx = it->top_nz_[x] + it->left_nz_[y];
-        const int non_zero =
-            TrellisQuantizeBlock(enc, tmp[n], rd->y_ac_levels[n], ctx, 0,
-                                 &dqm->y1_, dqm->lambda_trellis_i16_);
+        const int non_zero = TrellisQuantizeBlock(
+            enc, tmp[n], rd->y_ac_levels[n], ctx, TYPE_I16_AC, &dqm->y1_,
+            dqm->lambda_trellis_i16_);
         it->top_nz_[x] = it->left_nz_[y] = non_zero;
         rd->y_ac_levels[n][0] = 0;
         nz |= non_zero << n;
@@ -818,7 +834,7 @@ static int ReconstructIntra4(VP8EncIterator* const it,
   if (DO_TRELLIS_I4 && it->do_trellis_) {
     const int x = it->i4_ & 3, y = it->i4_ >> 2;
     const int ctx = it->top_nz_[x] + it->left_nz_[y];
-    nz = TrellisQuantizeBlock(enc, tmp, levels, ctx, 3, &dqm->y1_,
+    nz = TrellisQuantizeBlock(enc, tmp, levels, ctx, TYPE_I4_AC, &dqm->y1_,
                               dqm->lambda_trellis_i4_);
   } else {
     nz = VP8EncQuantizeBlock(tmp, levels, &dqm->y1_);
@@ -927,9 +943,9 @@ static int ReconstructUV(VP8EncIterator* const it, VP8ModeScore* const rd,
       for (y = 0; y < 2; ++y) {
         for (x = 0; x < 2; ++x, ++n) {
           const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y];
-          const int non_zero =
-              TrellisQuantizeBlock(enc, tmp[n], rd->uv_levels[n], ctx, 2,
-                                   &dqm->uv_, dqm->lambda_trellis_uv_);
+          const int non_zero = TrellisQuantizeBlock(
+              enc, tmp[n], rd->uv_levels[n], ctx, TYPE_CHROMA_A, &dqm->uv_,
+              dqm->lambda_trellis_uv_);
           it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] = non_zero;
           nz |= non_zero << n;
         }