libvpx: Add VP9 decoder.

source/libvpx/vp9/encoder/vp9_segmentation.c

+/*
+ *  Copyright (c) 2012 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+
+#include "limits.h"
+#include "vpx_mem/vpx_mem.h"
+#include "vp9/encoder/vp9_segmentation.h"
+#include "vp9/common/vp9_pred_common.h"
+
+void vp9_update_gf_useage_maps(VP9_COMP *cpi, VP9_COMMON *cm, MACROBLOCK *x) {
+  int mb_row, mb_col;
+
+  MODE_INFO *this_mb_mode_info = cm->mi;
+
+  x->gf_active_ptr = (signed char *)cpi->gf_active_flags;
+
+  if ((cm->frame_type == KEY_FRAME) || (cm->refresh_golden_frame)) {
+    // Reset Gf useage monitors
+    vpx_memset(cpi->gf_active_flags, 1, (cm->mb_rows * cm->mb_cols));
+    cpi->gf_active_count = cm->mb_rows * cm->mb_cols;
+  } else {
+    // for each macroblock row in image
+    for (mb_row = 0; mb_row < cm->mb_rows; mb_row++) {
+      // for each macroblock col in image
+      for (mb_col = 0; mb_col < cm->mb_cols; mb_col++) {
+
+        // If using golden then set GF active flag if not already set.
+        // If using last frame 0,0 mode then leave flag as it is
+        // else if using non 0,0 motion or intra modes then clear
+        // flag if it is currently set
+        if ((this_mb_mode_info->mbmi.ref_frame == GOLDEN_FRAME) ||
+            (this_mb_mode_info->mbmi.ref_frame == ALTREF_FRAME)) {
+          if (*(x->gf_active_ptr) == 0) {
+            *(x->gf_active_ptr) = 1;
+            cpi->gf_active_count++;
+          }
+        } else if ((this_mb_mode_info->mbmi.mode != ZEROMV) &&
+                   *(x->gf_active_ptr)) {
+          *(x->gf_active_ptr) = 0;
+          cpi->gf_active_count--;
+        }
+
+        x->gf_active_ptr++;          // Step onto next entry
+        this_mb_mode_info++;         // skip to next mb
+
+      }
+
+      // this is to account for the border
+      this_mb_mode_info++;
+    }
+  }
+}
+
+void vp9_enable_segmentation(VP9_PTR ptr) {
+  VP9_COMP *cpi = (VP9_COMP *)(ptr);
+
+  // Set the appropriate feature bit
+  cpi->mb.e_mbd.segmentation_enabled = 1;
+  cpi->mb.e_mbd.update_mb_segmentation_map = 1;
+  cpi->mb.e_mbd.update_mb_segmentation_data = 1;
+}
+
+void vp9_disable_segmentation(VP9_PTR ptr) {
+  VP9_COMP *cpi = (VP9_COMP *)(ptr);
+
+  // Clear the appropriate feature bit
+  cpi->mb.e_mbd.segmentation_enabled = 0;
+}
+
+void vp9_set_segmentation_map(VP9_PTR ptr,
+                              unsigned char *segmentation_map) {
+  VP9_COMP *cpi = (VP9_COMP *)(ptr);
+
+  // Copy in the new segmentation map
+  vpx_memcpy(cpi->segmentation_map, segmentation_map,
+             (cpi->common.mb_rows * cpi->common.mb_cols));
+
+  // Signal that the map should be updated.
+  cpi->mb.e_mbd.update_mb_segmentation_map = 1;
+  cpi->mb.e_mbd.update_mb_segmentation_data = 1;
+}
+
+void vp9_set_segment_data(VP9_PTR ptr,
+                          signed char *feature_data,
+                          unsigned char abs_delta) {
+  VP9_COMP *cpi = (VP9_COMP *)(ptr);
+
+  cpi->mb.e_mbd.mb_segment_abs_delta = abs_delta;
+
+  vpx_memcpy(cpi->mb.e_mbd.segment_feature_data, feature_data,
+             sizeof(cpi->mb.e_mbd.segment_feature_data));
+
+  // TBD ?? Set the feature mask
+  // vpx_memcpy(cpi->mb.e_mbd.segment_feature_mask, 0,
+  //            sizeof(cpi->mb.e_mbd.segment_feature_mask));
+}
+
+// Based on set of segment counts calculate a probability tree
+static void calc_segtree_probs(MACROBLOCKD *xd,
+                               int *segcounts,
+                               vp9_prob *segment_tree_probs) {
+  int count1, count2;
+  int tot_count;
+  int i;
+
+  // Blank the strtucture to start with
+  vpx_memset(segment_tree_probs, 0,
+             MB_FEATURE_TREE_PROBS * sizeof(*segment_tree_probs));
+
+  // Total count for all segments
+  count1 = segcounts[0] + segcounts[1];
+  count2 = segcounts[2] + segcounts[3];
+  tot_count = count1 + count2;
+
+  // Work out probabilities of each segment
+  if (tot_count)
+    segment_tree_probs[0] = (count1 * 255) / tot_count;
+  if (count1 > 0)
+    segment_tree_probs[1] = (segcounts[0] * 255) / count1;
+  if (count2 > 0)
+    segment_tree_probs[2] = (segcounts[2] * 255) / count2;
+
+  // Clamp probabilities to minimum allowed value
+  for (i = 0; i < MB_FEATURE_TREE_PROBS; i++) {
+    if (segment_tree_probs[i] == 0)
+      segment_tree_probs[i] = 1;
+  }
+}
+
+// Based on set of segment counts and probabilities calculate a cost estimate
+static int cost_segmap(MACROBLOCKD *xd,
+                       int *segcounts,
+                       vp9_prob *probs) {
+  int cost;
+  int count1, count2;
+
+  // Cost the top node of the tree
+  count1 = segcounts[0] + segcounts[1];
+  count2 = segcounts[2] + segcounts[3];
+  cost = count1 * vp9_cost_zero(probs[0]) +
+         count2 * vp9_cost_one(probs[0]);
+
+  // Now add the cost of each individual segment branch
+  if (count1 > 0)
+    cost += segcounts[0] * vp9_cost_zero(probs[1]) +
+            segcounts[1] * vp9_cost_one(probs[1]);
+
+  if (count2 > 0)
+    cost += segcounts[2] * vp9_cost_zero(probs[2]) +
+            segcounts[3] * vp9_cost_one(probs[2]);
+
+  return cost;
+
+}
+
+void vp9_choose_segmap_coding_method(VP9_COMP *cpi) {
+  VP9_COMMON *const cm = &cpi->common;
+  MACROBLOCKD *const xd = &cpi->mb.e_mbd;
+
+  int i;
+  int tot_count;
+  int no_pred_cost;
+  int t_pred_cost = INT_MAX;
+  int pred_context;
+
+  int mb_row, mb_col;
+  int segmap_index = 0;
+  unsigned char segment_id;
+
+  int temporal_predictor_count[PREDICTION_PROBS][2];
+  int no_pred_segcounts[MAX_MB_SEGMENTS];
+  int t_unpred_seg_counts[MAX_MB_SEGMENTS];
+
+  vp9_prob no_pred_tree[MB_FEATURE_TREE_PROBS];
+  vp9_prob t_pred_tree[MB_FEATURE_TREE_PROBS];
+  vp9_prob t_nopred_prob[PREDICTION_PROBS];
+
+#if CONFIG_SUPERBLOCKS
+  const int mis = cm->mode_info_stride;
+#endif
+
+  // Set default state for the segment tree probabilities and the
+  // temporal coding probabilities
+  vpx_memset(xd->mb_segment_tree_probs, 255,
+             sizeof(xd->mb_segment_tree_probs));
+  vpx_memset(cm->segment_pred_probs, 255,
+             sizeof(cm->segment_pred_probs));
+
+  vpx_memset(no_pred_segcounts, 0, sizeof(no_pred_segcounts));
+  vpx_memset(t_unpred_seg_counts, 0, sizeof(t_unpred_seg_counts));
+  vpx_memset(temporal_predictor_count, 0, sizeof(temporal_predictor_count));
+
+  // First of all generate stats regarding how well the last segment map
+  // predicts this one
+
+  // Initialize macroblock decoder mode info context for the first mb
+  // in the frame
+  xd->mode_info_context = cm->mi;
+
+  for (mb_row = 0; mb_row < cm->mb_rows; mb_row += 2) {
+    for (mb_col = 0; mb_col < cm->mb_cols; mb_col += 2) {
+      for (i = 0; i < 4; i++) {
+        static const int dx[4] = { +1, -1, +1, +1 };
+        static const int dy[4] = {  0, +1,  0, -1 };
+        int x_idx = i & 1, y_idx = i >> 1;
+
+        if (mb_col + x_idx >= cm->mb_cols ||
+            mb_row + y_idx >= cm->mb_rows) {
+          goto end;
+        }
+
+        xd->mb_to_top_edge = -((mb_row * 16) << 3);
+        xd->mb_to_left_edge = -((mb_col * 16) << 3);
+
+        segmap_index = (mb_row + y_idx) * cm->mb_cols + mb_col + x_idx;
+        segment_id = xd->mode_info_context->mbmi.segment_id;
+#if CONFIG_SUPERBLOCKS
+        if (xd->mode_info_context->mbmi.encoded_as_sb) {
+          if (mb_col + 1 < cm->mb_cols)
+            segment_id = segment_id &&
+                         xd->mode_info_context[1].mbmi.segment_id;
+          if (mb_row + 1 < cm->mb_rows) {
+            segment_id = segment_id &&
+                         xd->mode_info_context[mis].mbmi.segment_id;
+            if (mb_col + 1 < cm->mb_cols)
+              segment_id = segment_id &&
+                           xd->mode_info_context[mis + 1].mbmi.segment_id;
+          }
+          xd->mb_to_bottom_edge = ((cm->mb_rows - 2 - mb_row) * 16) << 3;
+          xd->mb_to_right_edge  = ((cm->mb_cols - 2 - mb_col) * 16) << 3;
+        } else {
+#endif
+          xd->mb_to_bottom_edge = ((cm->mb_rows - 1 - mb_row) * 16) << 3;
+          xd->mb_to_right_edge  = ((cm->mb_cols - 1 - mb_col) * 16) << 3;
+#if CONFIG_SUPERBLOCKS
+        }
+#endif
+
+        // Count the number of hits on each segment with no prediction
+        no_pred_segcounts[segment_id]++;
+
+        // Temporal prediction not allowed on key frames
+        if (cm->frame_type != KEY_FRAME) {
+          // Test to see if the segment id matches the predicted value.
+          int seg_predicted =
+            (segment_id == vp9_get_pred_mb_segid(cm, xd, segmap_index));
+
+          // Get the segment id prediction context
+          pred_context =
+            vp9_get_pred_context(cm, xd, PRED_SEG_ID);
+
+          // Store the prediction status for this mb and update counts
+          // as appropriate
+          vp9_set_pred_flag(xd, PRED_SEG_ID, seg_predicted);
+          temporal_predictor_count[pred_context][seg_predicted]++;
+
+          if (!seg_predicted)
+            // Update the "unpredicted" segment count
+            t_unpred_seg_counts[segment_id]++;
+        }
+
+#if CONFIG_SUPERBLOCKS
+        if (xd->mode_info_context->mbmi.encoded_as_sb) {
+          assert(!i);
+          xd->mode_info_context += 2;
+          break;
+        }
+#endif
+      end:
+        xd->mode_info_context += dx[i] + dy[i] * cm->mode_info_stride;
+      }
+    }
+
+    // this is to account for the border in mode_info_context
+    xd->mode_info_context -= mb_col;
+    xd->mode_info_context += cm->mode_info_stride * 2;
+  }
+
+  // Work out probability tree for coding segments without prediction
+  // and the cost.
+  calc_segtree_probs(xd, no_pred_segcounts, no_pred_tree);
+  no_pred_cost = cost_segmap(xd, no_pred_segcounts, no_pred_tree);
+
+  // Key frames cannot use temporal prediction
+  if (cm->frame_type != KEY_FRAME) {
+    // Work out probability tree for coding those segments not
+    // predicted using the temporal method and the cost.
+    calc_segtree_probs(xd, t_unpred_seg_counts, t_pred_tree);
+    t_pred_cost = cost_segmap(xd, t_unpred_seg_counts, t_pred_tree);
+
+    // Add in the cost of the signalling for each prediction context
+    for (i = 0; i < PREDICTION_PROBS; i++) {
+      tot_count = temporal_predictor_count[i][0] +
+                  temporal_predictor_count[i][1];
+
+      // Work out the context probabilities for the segment
+      // prediction flag
+      if (tot_count) {
+        t_nopred_prob[i] = (temporal_predictor_count[i][0] * 255) /
+                           tot_count;
+
+        // Clamp to minimum allowed value
+        if (t_nopred_prob[i] < 1)
+          t_nopred_prob[i] = 1;
+      } else
+        t_nopred_prob[i] = 1;
+
+      // Add in the predictor signaling cost
+      t_pred_cost += (temporal_predictor_count[i][0] *
+                      vp9_cost_zero(t_nopred_prob[i])) +
+                     (temporal_predictor_count[i][1] *
+                      vp9_cost_one(t_nopred_prob[i]));
+    }
+  }
+
+  // Now choose which coding method to use.
+  if (t_pred_cost < no_pred_cost) {
+    cm->temporal_update = 1;
+    vpx_memcpy(xd->mb_segment_tree_probs,
+               t_pred_tree, sizeof(t_pred_tree));
+    vpx_memcpy(&cm->segment_pred_probs,
+               t_nopred_prob, sizeof(t_nopred_prob));
+  } else {
+    cm->temporal_update = 0;
+    vpx_memcpy(xd->mb_segment_tree_probs,
+               no_pred_tree, sizeof(no_pred_tree));
+  }
+}