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Limit cyclic refresh revisitng blocks at the same quantizer.

For screen content don't refresh a block at a quantizer higher than
it was last coded at. PReviosuly at realtime speeds the encoder had a
tendency to recode a block from GOLDEN with a higher Q than it was last
coded at.

Change-Id: Iacd561806c769dcce1a81b9827ffc70090f5ba18

--- a/vp9/encoder/vp9_aq_cyclicrefresh.c

+++ b/vp9/encoder/vp9_aq_cyclicrefresh.c

@@ -39,6 +39,8 @@

   int rdmult;

   // Cyclic refresh map.

   signed char *map;

+  // Map of the last q a block was coded at.

+  uint8_t *last_coded_q_map;

   // Thresholds applied to the projected rate/distortion of the coding block,

   // when deciding whether block should be refreshed.

   int64_t thresh_rate_sb;

@@ -51,11 +53,11 @@

   // Boost factor for rate target ratio, for segment CR_SEGMENT_ID_BOOST2.

   double rate_boost_fac;

   double low_content_avg;

-  int qindex_delta_seg1;

-  int qindex_delta_seg2;

+  int qindex_delta[3];

 };

 CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols) {

+  size_t last_coded_q_map_size;

   CYCLIC_REFRESH *const cr = vpx_calloc(1, sizeof(*cr));

   if (cr == NULL)

     return NULL;

@@ -65,6 +67,14 @@

     vpx_free(cr);

     return NULL;

   }

+  last_coded_q_map_size = mi_rows * mi_cols * sizeof(*cr->last_coded_q_map);

+  cr->last_coded_q_map = vpx_malloc(last_coded_q_map_size);

+  if (cr->last_coded_q_map == NULL) {

+    vpx_free(cr);

+    return NULL;

+  }

+  assert(MAXQ <= 255);

+  memset(cr->last_coded_q_map, MAXQ, last_coded_q_map_size);

   return cr;

 }

@@ -71,6 +81,7 @@

 void vp9_cyclic_refresh_free(CYCLIC_REFRESH *cr) {

   vpx_free(cr->map);

+  vpx_free(cr->last_coded_q_map);

   vpx_free(cr);

 }

@@ -159,11 +170,11 @@

                              correction_factor, cm->bit_depth) +

                              weight_segment1 *

       vp9_estimate_bits_at_q(cm->frame_type,

-                             cm->base_qindex + cr->qindex_delta_seg1, mbs,

+                             cm->base_qindex + cr->qindex_delta[1], mbs,

                              correction_factor, cm->bit_depth) +

                              weight_segment2 *

       vp9_estimate_bits_at_q(cm->frame_type,

-                             cm->base_qindex + cr->qindex_delta_seg2, mbs,

+                             cm->base_qindex + cr->qindex_delta[2], mbs,

                              correction_factor, cm->bit_depth));

   return estimated_bits;

 }

@@ -248,9 +259,16 @@

   // copy mbmi->segment_id into global segmentation map.

   for (y = 0; y < ymis; y++)

     for (x = 0; x < xmis; x++) {

-      cr->map[block_index + y * cm->mi_cols + x] = new_map_value;

-      cpi->segmentation_map[block_index + y * cm->mi_cols + x] =

-          mbmi->segment_id;

+      int map_offset = block_index + y * cm->mi_cols + x;

+      cr->map[map_offset] = new_map_value;

+      cpi->segmentation_map[map_offset] = mbmi->segment_id;

+      // Inter skip blocks were clearly not coded at the current qindex, so

+      // don't update the map for them. For cases where motion is non-zero or

+      // the reference frame isn't the previous frame, the previous value in

+      // the map for this spatial location is not entirely correct.

+      if (!is_inter_block(mbmi) || !skip)

+        cr->last_coded_q_map[map_offset] = clamp(

+            cm->base_qindex + cr->qindex_delta[mbmi->segment_id], 0, MAXQ);

     }

 }

@@ -384,6 +402,10 @@

     int sb_col_index = i - sb_row_index * sb_cols;

     int mi_row = sb_row_index * MI_BLOCK_SIZE;

     int mi_col = sb_col_index * MI_BLOCK_SIZE;

+    int qindex_thresh =

+        cpi->oxcf.content == VP9E_CONTENT_SCREEN

+            ? vp9_get_qindex(&cm->seg, CR_SEGMENT_ID_BOOST2, cm->base_qindex)

+            : 0;

     assert(mi_row >= 0 && mi_row < cm->mi_rows);

     assert(mi_col >= 0 && mi_col < cm->mi_cols);

     bl_index = mi_row * cm->mi_cols + mi_col;

@@ -399,7 +421,8 @@

         // for possible boost/refresh (segment 1). The segment id may get

         // reset to 0 later if block gets coded anything other than ZEROMV.

         if (cr->map[bl_index2] == 0) {

-          sum_map++;

+          if (cr->last_coded_q_map[bl_index2] > qindex_thresh)

+            sum_map++;

         } else if (cr->map[bl_index2] < 0) {

           cr->map[bl_index2]++;

         }

@@ -466,8 +489,11 @@

     unsigned char *const seg_map = cpi->segmentation_map;

     memset(seg_map, 0, cm->mi_rows * cm->mi_cols);

     vp9_disable_segmentation(&cm->seg);

-    if (cm->frame_type == KEY_FRAME)

+    if (cm->frame_type == KEY_FRAME) {

+      memset(cr->last_coded_q_map, MAXQ,

+             cm->mi_rows * cm->mi_cols * sizeof(*cr->last_coded_q_map));

       cr->sb_index = 0;

+    }

     return;

   } else {

     int qindex_delta = 0;

@@ -505,7 +531,7 @@

     // Set the q delta for segment BOOST1.

     qindex_delta = compute_deltaq(cpi, cm->base_qindex, cr->rate_ratio_qdelta);

-    cr->qindex_delta_seg1 = qindex_delta;

+    cr->qindex_delta[1] = qindex_delta;

     // Compute rd-mult for segment BOOST1.

     qindex2 = clamp(cm->base_qindex + cm->y_dc_delta_q + qindex_delta, 0, MAXQ);

@@ -518,7 +544,7 @@

     qindex_delta = compute_deltaq(cpi, cm->base_qindex,

                                   MIN(CR_MAX_RATE_TARGET_RATIO,

                                   cr->rate_boost_fac * cr->rate_ratio_qdelta));

-    cr->qindex_delta_seg2 = qindex_delta;

+    cr->qindex_delta[2] = qindex_delta;

     vp9_set_segdata(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q, qindex_delta);

     // Update the segmentation and refresh map.