commit d13c24a57ded89f8667c498ed796ba2d5777e995
author hui su <huisu@google.com> Fri Apr 07 16:13:07 2017 -0700
committer Hui Su <huisu@google.com> Thu Apr 20 03:26:51 2017 +0000
tree 40c8fdea04a0f771b6625ac3a9cc93f4dd21fa65
parent d8cd55f4dd090d5ca27b6b942f4e3f200f253e9e

palette-delta-encoding experiment

Transmit palette colors with delta encoding.
Coding gain on scrren_content testset:
overall 0.67%  keyframe 1.37%

Change-Id: I72ce9061dfddf933e9f7530f069955afcb07edf8

av1/encoder/rdopt.c

diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index 89161d9..07869a9 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -2541,12 +2541,13 @@
       extend_palette_color_map(color_map, cols, rows, block_width,
                                block_height);
       palette_mode_cost =
-          dc_mode_cost + cpi->common.bit_depth * k * av1_cost_bit(128, 0) +
+          dc_mode_cost +
           cpi->palette_y_size_cost[bsize - BLOCK_8X8][k - PALETTE_MIN_SIZE] +
           write_uniform_cost(k, color_map[0]) +
           av1_cost_bit(
               av1_default_palette_y_mode_prob[bsize - BLOCK_8X8][palette_ctx],
               1);
+      palette_mode_cost += av1_palette_color_cost_y(pmi, cpi->common.bit_depth);
       for (i = 0; i < rows; ++i) {
         for (j = (i == 0 ? 1 : 0); j < cols; ++j) {
           int color_idx;
@@ -4585,6 +4586,22 @@
         centroids[i * 2 + 1] = lb_v + (2 * i + 1) * (ub_v - lb_v) / n / 2;
       }
       av1_k_means(data, centroids, color_map, rows * cols, n, 2, max_itr);
+#if CONFIG_PALETTE_DELTA_ENCODING
+      // Sort the U channel colors in ascending order.
+      for (i = 0; i < 2 * (n - 1); i += 2) {
+        int min_idx = i;
+        float min_val = centroids[i];
+        for (j = i + 2; j < 2 * n; j += 2)
+          if (centroids[j] < min_val) min_val = centroids[j], min_idx = j;
+        if (min_idx != i) {
+          float temp_u = centroids[i], temp_v = centroids[i + 1];
+          centroids[i] = centroids[min_idx];
+          centroids[i + 1] = centroids[min_idx + 1];
+          centroids[min_idx] = temp_u, centroids[min_idx + 1] = temp_v;
+        }
+      }
+      av1_calc_indices(data, centroids, color_map, rows * cols, n, 2);
+#endif  // CONFIG_PALETTE_DELTA_ENCODING
       extend_palette_color_map(color_map, cols, rows, plane_block_width,
                                plane_block_height);
       pmi->palette_size[1] = n;
@@ -4605,12 +4622,11 @@
       if (tokenonly_rd_stats.rate == INT_MAX) continue;
       this_rate =
           tokenonly_rd_stats.rate + dc_mode_cost +
-          2 * cpi->common.bit_depth * n * av1_cost_bit(128, 0) +
           cpi->palette_uv_size_cost[bsize - BLOCK_8X8][n - PALETTE_MIN_SIZE] +
           write_uniform_cost(n, color_map[0]) +
           av1_cost_bit(
               av1_default_palette_uv_mode_prob[pmi->palette_size[0] > 0], 1);
-
+      this_rate += av1_palette_color_cost_uv(pmi, cpi->common.bit_depth);
       for (i = 0; i < rows; ++i) {
         for (j = (i == 0 ? 1 : 0); j < cols; ++j) {
           int color_idx;