libvpx: Add VP9 decoder.

source/libvpx/vp9/encoder/vp9_encodeframe.c

+/*
+ *  Copyright (c) 2010 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 "vpx_ports/config.h"
+#include "vp9/encoder/vp9_encodeframe.h"
+#include "vp9/encoder/vp9_encodemb.h"
+#include "vp9/encoder/vp9_encodemv.h"
+#include "vp9/common/vp9_common.h"
+#include "vp9/encoder/vp9_onyx_int.h"
+#include "vp9/common/vp9_extend.h"
+#include "vp9/common/vp9_entropymode.h"
+#include "vp9/common/vp9_quant_common.h"
+#include "vp9/encoder/vp9_segmentation.h"
+#include "vp9/common/vp9_setupintrarecon.h"
+#include "vp9/common/vp9_reconintra4x4.h"
+#include "vp9/encoder/vp9_encodeintra.h"
+#include "vp9/common/vp9_reconinter.h"
+#include "vp9/common/vp9_invtrans.h"
+#include "vp9/encoder/vp9_rdopt.h"
+#include "vp9/common/vp9_findnearmv.h"
+#include "vp9/common/vp9_reconintra.h"
+#include "vp9/common/vp9_seg_common.h"
+#include "vp9/encoder/vp9_tokenize.h"
+#include "vp9_rtcd.h"
+#include <stdio.h>
+#include <math.h>
+#include <limits.h>
+#include "vpx_ports/vpx_timer.h"
+#include "vp9/common/vp9_pred_common.h"
+#include "vp9/common/vp9_mvref_common.h"
+
+#define DBG_PRNT_SEGMAP 0
+
+// #define ENC_DEBUG
+#ifdef ENC_DEBUG
+int enc_debug = 0;
+#endif
+
+static void encode_macroblock(VP9_COMP *cpi, MACROBLOCK *x,
+                              TOKENEXTRA **t, int recon_yoffset,
+                              int recon_uvoffset, int output_enabled,
+                              int mb_col, int mb_row);
+
+static void encode_superblock(VP9_COMP *cpi, MACROBLOCK *x,
+                              TOKENEXTRA **t, int recon_yoffset,
+                              int recon_uvoffset, int mb_col, int mb_row);
+
+static void adjust_act_zbin(VP9_COMP *cpi, MACROBLOCK *x);
+
+#ifdef MODE_STATS
+unsigned int inter_y_modes[MB_MODE_COUNT];
+unsigned int inter_uv_modes[VP9_UV_MODES];
+unsigned int inter_b_modes[B_MODE_COUNT];
+unsigned int y_modes[VP9_YMODES];
+unsigned int i8x8_modes[VP9_I8X8_MODES];
+unsigned int uv_modes[VP9_UV_MODES];
+unsigned int uv_modes_y[VP9_YMODES][VP9_UV_MODES];
+unsigned int b_modes[B_MODE_COUNT];
+#endif
+
+
+/* activity_avg must be positive, or flat regions could get a zero weight
+ *  (infinite lambda), which confounds analysis.
+ * This also avoids the need for divide by zero checks in
+ *  vp9_activity_masking().
+ */
+#define VP9_ACTIVITY_AVG_MIN (64)
+
+/* This is used as a reference when computing the source variance for the
+ *  purposes of activity masking.
+ * Eventually this should be replaced by custom no-reference routines,
+ *  which will be faster.
+ */
+static const unsigned char VP9_VAR_OFFS[16] = {
+  128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128
+};
+
+
+// Original activity measure from Tim T's code.
+static unsigned int tt_activity_measure(VP9_COMP *cpi, MACROBLOCK *x) {
+  unsigned int act;
+  unsigned int sse;
+  /* TODO: This could also be done over smaller areas (8x8), but that would
+   *  require extensive changes elsewhere, as lambda is assumed to be fixed
+   *  over an entire MB in most of the code.
+   * Another option is to compute four 8x8 variances, and pick a single
+   *  lambda using a non-linear combination (e.g., the smallest, or second
+   *  smallest, etc.).
+   */
+  act = vp9_variance16x16(x->src.y_buffer, x->src.y_stride, VP9_VAR_OFFS, 0,
+                          &sse);
+  act = act << 4;
+
+  /* If the region is flat, lower the activity some more. */
+  if (act < 8 << 12)
+    act = act < 5 << 12 ? act : 5 << 12;
+
+  return act;
+}
+
+// Stub for alternative experimental activity measures.
+static unsigned int alt_activity_measure(VP9_COMP *cpi,
+                                         MACROBLOCK *x, int use_dc_pred) {
+  return vp9_encode_intra(cpi, x, use_dc_pred);
+}
+
+
+// Measure the activity of the current macroblock
+// What we measure here is TBD so abstracted to this function
+#define ALT_ACT_MEASURE 1
+static unsigned int mb_activity_measure(VP9_COMP *cpi, MACROBLOCK *x,
+                                        int mb_row, int mb_col) {
+  unsigned int mb_activity;
+
+  if (ALT_ACT_MEASURE) {
+    int use_dc_pred = (mb_col || mb_row) && (!mb_col || !mb_row);
+
+    // Or use and alternative.
+    mb_activity = alt_activity_measure(cpi, x, use_dc_pred);
+  } else {
+    // Original activity measure from Tim T's code.
+    mb_activity = tt_activity_measure(cpi, x);
+  }
+
+  if (mb_activity < VP9_ACTIVITY_AVG_MIN)
+    mb_activity = VP9_ACTIVITY_AVG_MIN;
+
+  return mb_activity;
+}
+
+// Calculate an "average" mb activity value for the frame
+#define ACT_MEDIAN 0
+static void calc_av_activity(VP9_COMP *cpi, int64_t activity_sum) {
+#if ACT_MEDIAN
+  // Find median: Simple n^2 algorithm for experimentation
+  {
+    unsigned int median;
+    unsigned int i, j;
+    unsigned int *sortlist;
+    unsigned int tmp;
+
+    // Create a list to sort to
+    CHECK_MEM_ERROR(sortlist,
+    vpx_calloc(sizeof(unsigned int),
+    cpi->common.MBs));
+
+    // Copy map to sort list
+    vpx_memcpy(sortlist, cpi->mb_activity_map,
+    sizeof(unsigned int) * cpi->common.MBs);
+
+
+    // Ripple each value down to its correct position
+    for (i = 1; i < cpi->common.MBs; i ++) {
+      for (j = i; j > 0; j --) {
+        if (sortlist[j] < sortlist[j - 1]) {
+          // Swap values
+          tmp = sortlist[j - 1];
+          sortlist[j - 1] = sortlist[j];
+          sortlist[j] = tmp;
+        } else
+          break;
+      }
+    }
+
+    // Even number MBs so estimate median as mean of two either side.
+    median = (1 + sortlist[cpi->common.MBs >> 1] +
+              sortlist[(cpi->common.MBs >> 1) + 1]) >> 1;
+
+    cpi->activity_avg = median;
+
+    vpx_free(sortlist);
+  }
+#else
+  // Simple mean for now
+  cpi->activity_avg = (unsigned int)(activity_sum / cpi->common.MBs);
+#endif
+
+  if (cpi->activity_avg < VP9_ACTIVITY_AVG_MIN)
+    cpi->activity_avg = VP9_ACTIVITY_AVG_MIN;
+
+  // Experimental code: return fixed value normalized for several clips
+  if (ALT_ACT_MEASURE)
+    cpi->activity_avg = 100000;
+}
+
+#define USE_ACT_INDEX   0
+#define OUTPUT_NORM_ACT_STATS   0
+
+#if USE_ACT_INDEX
+// Calculate and activity index for each mb
+static void calc_activity_index(VP9_COMP *cpi, MACROBLOCK *x) {
+  VP9_COMMON *const cm = &cpi->common;
+  int mb_row, mb_col;
+
+  int64_t act;
+  int64_t a;
+  int64_t b;
+
+#if OUTPUT_NORM_ACT_STATS
+  FILE *f = fopen("norm_act.stt", "a");
+  fprintf(f, "\n%12d\n", cpi->activity_avg);
+#endif
+
+  // Reset pointers to start of activity map
+  x->mb_activity_ptr = cpi->mb_activity_map;
+
+  // Calculate normalized mb activity number.
+  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++) {
+      // Read activity from the map
+      act = *(x->mb_activity_ptr);
+
+      // Calculate a normalized activity number
+      a = act + 4 * cpi->activity_avg;
+      b = 4 * act + cpi->activity_avg;
+
+      if (b >= a)
+        *(x->activity_ptr) = (int)((b + (a >> 1)) / a) - 1;
+      else
+        *(x->activity_ptr) = 1 - (int)((a + (b >> 1)) / b);
+
+#if OUTPUT_NORM_ACT_STATS
+      fprintf(f, " %6d", *(x->mb_activity_ptr));
+#endif
+      // Increment activity map pointers
+      x->mb_activity_ptr++;
+    }
+
+#if OUTPUT_NORM_ACT_STATS
+    fprintf(f, "\n");
+#endif
+
+  }
+
+#if OUTPUT_NORM_ACT_STATS
+  fclose(f);
+#endif
+
+}
+#endif
+
+// Loop through all MBs. Note activity of each, average activity and
+// calculate a normalized activity for each
+static void build_activity_map(VP9_COMP *cpi) {
+  MACROBLOCK *const x = &cpi->mb;
+  MACROBLOCKD *xd = &x->e_mbd;
+  VP9_COMMON *const cm = &cpi->common;
+
+#if ALT_ACT_MEASURE
+  YV12_BUFFER_CONFIG *new_yv12 = &cm->yv12_fb[cm->new_fb_idx];
+  int recon_yoffset;
+  int recon_y_stride = new_yv12->y_stride;
+#endif
+
+  int mb_row, mb_col;
+  unsigned int mb_activity;
+  int64_t activity_sum = 0;
+
+  // for each macroblock row in image
+  for (mb_row = 0; mb_row < cm->mb_rows; mb_row++) {
+#if ALT_ACT_MEASURE
+    // reset above block coeffs
+    xd->up_available = (mb_row != 0);
+    recon_yoffset = (mb_row * recon_y_stride * 16);
+#endif
+    // for each macroblock col in image
+    for (mb_col = 0; mb_col < cm->mb_cols; mb_col++) {
+#if ALT_ACT_MEASURE
+      xd->dst.y_buffer = new_yv12->y_buffer + recon_yoffset;
+      xd->left_available = (mb_col != 0);
+      recon_yoffset += 16;
+#endif
+#if !CONFIG_SUPERBLOCKS
+      // Copy current mb to a buffer
+      vp9_copy_mem16x16(x->src.y_buffer, x->src.y_stride, x->thismb, 16);
+#endif
+
+      // measure activity
+      mb_activity = mb_activity_measure(cpi, x, mb_row, mb_col);
+
+      // Keep frame sum
+      activity_sum += mb_activity;
+
+      // Store MB level activity details.
+      *x->mb_activity_ptr = mb_activity;
+
+      // Increment activity map pointer
+      x->mb_activity_ptr++;
+
+      // adjust to the next column of source macroblocks
+      x->src.y_buffer += 16;
+    }
+
+
+    // adjust to the next row of mbs
+    x->src.y_buffer += 16 * x->src.y_stride - 16 * cm->mb_cols;
+
+#if ALT_ACT_MEASURE
+    // extend the recon for intra prediction
+    vp9_extend_mb_row(new_yv12, xd->dst.y_buffer + 16,
+                      xd->dst.u_buffer + 8, xd->dst.v_buffer + 8);
+#endif
+
+  }
+
+  // Calculate an "average" MB activity
+  calc_av_activity(cpi, activity_sum);
+
+#if USE_ACT_INDEX
+  // Calculate an activity index number of each mb
+  calc_activity_index(cpi, x);
+#endif
+
+}
+
+// Macroblock activity masking
+void vp9_activity_masking(VP9_COMP *cpi, MACROBLOCK *x) {
+#if USE_ACT_INDEX
+  x->rdmult += *(x->mb_activity_ptr) * (x->rdmult >> 2);
+  x->errorperbit = x->rdmult * 100 / (110 * x->rddiv);
+  x->errorperbit += (x->errorperbit == 0);
+#else
+  int64_t a;
+  int64_t b;
+  int64_t act = *(x->mb_activity_ptr);
+
+  // Apply the masking to the RD multiplier.
+  a = act + (2 * cpi->activity_avg);
+  b = (2 * act) + cpi->activity_avg;
+
+  x->rdmult = (unsigned int)(((int64_t)x->rdmult * b + (a >> 1)) / a);
+  x->errorperbit = x->rdmult * 100 / (110 * x->rddiv);
+  x->errorperbit += (x->errorperbit == 0);
+#endif
+
+  // Activity based Zbin adjustment
+  adjust_act_zbin(cpi, x);
+}
+
+#if CONFIG_NEW_MVREF
+static int vp9_cost_mv_ref_id(vp9_prob * ref_id_probs, int mv_ref_id) {
+  int cost;
+
+  // Encode the index for the MV reference.
+  switch (mv_ref_id) {
+    case 0:
+      cost = vp9_cost_zero(ref_id_probs[0]);
+      break;
+    case 1:
+      cost = vp9_cost_one(ref_id_probs[0]);
+      cost += vp9_cost_zero(ref_id_probs[1]);
+      break;
+    case 2:
+      cost = vp9_cost_one(ref_id_probs[0]);
+      cost += vp9_cost_one(ref_id_probs[1]);
+      cost += vp9_cost_zero(ref_id_probs[2]);
+      break;
+    case 3:
+      cost = vp9_cost_one(ref_id_probs[0]);
+      cost += vp9_cost_one(ref_id_probs[1]);
+      cost += vp9_cost_one(ref_id_probs[2]);
+      break;
+
+      // TRAP.. This should not happen
+    default:
+      assert(0);
+      break;
+  }
+  return cost;
+}
+
+// Estimate the cost of each coding the vector using each reference candidate
+static unsigned int pick_best_mv_ref(MACROBLOCK *x,
+                                     MV_REFERENCE_FRAME ref_frame,
+                                     int_mv target_mv,
+                                     int_mv * mv_ref_list,
+                                     int_mv * best_ref) {
+  int i;
+  int best_index = 0;
+  int cost, cost2;
+  int zero_seen = (mv_ref_list[0].as_int) ? FALSE : TRUE;
+  MACROBLOCKD *xd = &x->e_mbd;
+  int max_mv = MV_MAX;
+
+  cost = vp9_cost_mv_ref_id(xd->mb_mv_ref_id_probs[ref_frame], 0) +
+         vp9_mv_bit_cost(&target_mv, &mv_ref_list[0], x->nmvjointcost,
+                         x->mvcost, 96, xd->allow_high_precision_mv);
+
+  // Use 4 for now : for (i = 1; i < MAX_MV_REFS; ++i ) {
+  for (i = 1; i < 4; ++i) {
+    // If we see a 0,0 reference vector for a second time we have reached
+    // the end of the list of valid candidate vectors.
+    if (!mv_ref_list[i].as_int) {
+      if (zero_seen)
+        break;
+      else
+        zero_seen = TRUE;
+    }
+
+    // Check for cases where the reference choice would give rise to an
+    // uncodable/out of range residual for row or col.
+    if ((abs(target_mv.as_mv.row - mv_ref_list[i].as_mv.row) > max_mv) ||
+        (abs(target_mv.as_mv.col - mv_ref_list[i].as_mv.col) > max_mv)) {
+      continue;
+    }
+
+    cost2 = vp9_cost_mv_ref_id(xd->mb_mv_ref_id_probs[ref_frame], i) +
+            vp9_mv_bit_cost(&target_mv, &mv_ref_list[i], x->nmvjointcost,
+                            x->mvcost, 96, xd->allow_high_precision_mv);
+
+    if (cost2 < cost) {
+      cost = cost2;
+      best_index = i;
+    }
+  }
+
+  best_ref->as_int = mv_ref_list[best_index].as_int;
+
+  return best_index;
+}
+#endif
+
+static void update_state(VP9_COMP *cpi, MACROBLOCK *x,
+                         PICK_MODE_CONTEXT *ctx) {
+  int i;
+  MACROBLOCKD *xd = &x->e_mbd;
+  MODE_INFO *mi = &ctx->mic;
+  MB_MODE_INFO * mbmi = &xd->mode_info_context->mbmi;
+  int mb_mode = mi->mbmi.mode;
+  int mb_mode_index = ctx->best_mode_index;
+
+#if CONFIG_DEBUG
+  assert(mb_mode < MB_MODE_COUNT);
+  assert(mb_mode_index < MAX_MODES);
+  assert(mi->mbmi.ref_frame < MAX_REF_FRAMES);
+#endif
+
+  // Restore the coding context of the MB to that that was in place
+  // when the mode was picked for it
+  vpx_memcpy(xd->mode_info_context, mi, sizeof(MODE_INFO));
+#if CONFIG_SUPERBLOCKS
+  if (mi->mbmi.encoded_as_sb) {
+    const int mis = cpi->common.mode_info_stride;
+    if (xd->mb_to_right_edge >= 0)
+      vpx_memcpy(xd->mode_info_context + 1, mi, sizeof(MODE_INFO));
+    if (xd->mb_to_bottom_edge >= 0) {
+      vpx_memcpy(xd->mode_info_context + mis, mi, sizeof(MODE_INFO));
+      if (xd->mb_to_right_edge >= 0)
+        vpx_memcpy(xd->mode_info_context + mis + 1, mi, sizeof(MODE_INFO));
+    }
+  }
+#endif
+
+  if (mb_mode == B_PRED) {
+    for (i = 0; i < 16; i++) {
+      xd->block[i].bmi.as_mode = xd->mode_info_context->bmi[i].as_mode;
+      assert(xd->block[i].bmi.as_mode.first < B_MODE_COUNT);
+    }
+  } else if (mb_mode == I8X8_PRED) {
+    for (i = 0; i < 16; i++) {
+      xd->block[i].bmi = xd->mode_info_context->bmi[i];
+    }
+  } else if (mb_mode == SPLITMV) {
+    vpx_memcpy(x->partition_info, &ctx->partition_info,
+               sizeof(PARTITION_INFO));
+
+    mbmi->mv[0].as_int = x->partition_info->bmi[15].mv.as_int;
+    mbmi->mv[1].as_int = x->partition_info->bmi[15].second_mv.as_int;
+  }
+
+  {
+    int segment_id = mbmi->segment_id;
+    if (!vp9_segfeature_active(xd, segment_id, SEG_LVL_EOB) ||
+        vp9_get_segdata(xd, segment_id, SEG_LVL_EOB)) {
+      for (i = 0; i < NB_TXFM_MODES; i++) {
+        cpi->rd_tx_select_diff[i] += ctx->txfm_rd_diff[i];
+      }
+    }
+  }
+
+  if (cpi->common.frame_type == KEY_FRAME) {
+    // Restore the coding modes to that held in the coding context
+    // if (mb_mode == B_PRED)
+    //    for (i = 0; i < 16; i++)
+    //    {
+    //        xd->block[i].bmi.as_mode =
+    //                          xd->mode_info_context->bmi[i].as_mode;
+    //        assert(xd->mode_info_context->bmi[i].as_mode < MB_MODE_COUNT);
+    //    }
+#if CONFIG_INTERNAL_STATS
+    static const int kf_mode_index[] = {
+      THR_DC /*DC_PRED*/,
+      THR_V_PRED /*V_PRED*/,
+      THR_H_PRED /*H_PRED*/,
+      THR_D45_PRED /*D45_PRED*/,
+      THR_D135_PRED /*D135_PRED*/,
+      THR_D117_PRED /*D117_PRED*/,
+      THR_D153_PRED /*D153_PRED*/,
+      THR_D27_PRED /*D27_PRED*/,
+      THR_D63_PRED /*D63_PRED*/,
+      THR_TM /*TM_PRED*/,
+      THR_I8X8_PRED /*I8X8_PRED*/,
+      THR_B_PRED /*B_PRED*/,
+    };
+    cpi->mode_chosen_counts[kf_mode_index[mb_mode]]++;
+#endif
+  } else {
+    /*
+            // Reduce the activation RD thresholds for the best choice mode
+            if ((cpi->rd_baseline_thresh[mb_mode_index] > 0) &&
+                (cpi->rd_baseline_thresh[mb_mode_index] < (INT_MAX >> 2)))
+            {
+                int best_adjustment = (cpi->rd_thresh_mult[mb_mode_index] >> 2);
+
+                cpi->rd_thresh_mult[mb_mode_index] =
+                        (cpi->rd_thresh_mult[mb_mode_index]
+                         >= (MIN_THRESHMULT + best_adjustment)) ?
+                                cpi->rd_thresh_mult[mb_mode_index] - best_adjustment :
+                                MIN_THRESHMULT;
+                cpi->rd_threshes[mb_mode_index] =
+                        (cpi->rd_baseline_thresh[mb_mode_index] >> 7)
+                        * cpi->rd_thresh_mult[mb_mode_index];
+
+            }
+    */
+    // Note how often each mode chosen as best
+    cpi->mode_chosen_counts[mb_mode_index]++;
+    if (mbmi->mode == SPLITMV || mbmi->mode == NEWMV) {
+      int_mv best_mv, best_second_mv;
+      MV_REFERENCE_FRAME rf = mbmi->ref_frame;
+#if CONFIG_NEW_MVREF
+      unsigned int best_index;
+      MV_REFERENCE_FRAME sec_ref_frame = mbmi->second_ref_frame;
+#endif
+      best_mv.as_int = ctx->best_ref_mv.as_int;
+      best_second_mv.as_int = ctx->second_best_ref_mv.as_int;
+      if (mbmi->mode == NEWMV) {
+        best_mv.as_int = mbmi->ref_mvs[rf][0].as_int;
+        best_second_mv.as_int = mbmi->ref_mvs[mbmi->second_ref_frame][0].as_int;
+#if CONFIG_NEW_MVREF
+        best_index = pick_best_mv_ref(x, rf, mbmi->mv[0],
+                                      mbmi->ref_mvs[rf], &best_mv);
+        mbmi->best_index = best_index;
+
+        if (mbmi->second_ref_frame > 0) {
+          unsigned int best_index;
+          best_index =
+              pick_best_mv_ref(x, sec_ref_frame, mbmi->mv[1],
+                               mbmi->ref_mvs[sec_ref_frame],
+                               &best_second_mv);
+          mbmi->best_second_index = best_index;
+        }
+#endif
+      }
+      mbmi->best_mv.as_int = best_mv.as_int;
+      mbmi->best_second_mv.as_int = best_second_mv.as_int;
+      vp9_update_nmv_count(cpi, x, &best_mv, &best_second_mv);
+    }
+#if CONFIG_COMP_INTERINTRA_PRED
+    if (mbmi->mode >= NEARESTMV && mbmi->mode < SPLITMV &&
+        mbmi->second_ref_frame <= INTRA_FRAME) {
+      if (mbmi->second_ref_frame == INTRA_FRAME) {
+        ++cpi->interintra_count[1];
+        ++cpi->ymode_count[mbmi->interintra_mode];
+#if SEPARATE_INTERINTRA_UV
+        ++cpi->y_uv_mode_count[mbmi->interintra_mode][mbmi->interintra_uv_mode];
+#endif
+      } else {
+        ++cpi->interintra_count[0];
+      }
+    }
+    if (cpi->common.mcomp_filter_type == SWITCHABLE &&
+        mbmi->mode >= NEARESTMV &&
+        mbmi->mode <= SPLITMV) {
+      ++cpi->switchable_interp_count
+          [vp9_get_pred_context(&cpi->common, xd, PRED_SWITCHABLE_INTERP)]
+          [vp9_switchable_interp_map[mbmi->interp_filter]];
+    }
+#endif
+
+    cpi->prediction_error += ctx->distortion;
+    cpi->intra_error += ctx->intra_error;
+
+    cpi->rd_comp_pred_diff[SINGLE_PREDICTION_ONLY] += ctx->single_pred_diff;
+    cpi->rd_comp_pred_diff[COMP_PREDICTION_ONLY]   += ctx->comp_pred_diff;
+    cpi->rd_comp_pred_diff[HYBRID_PREDICTION]      += ctx->hybrid_pred_diff;
+  }
+}
+
+static void pick_mb_modes(VP9_COMP *cpi,
+                          VP9_COMMON *cm,
+                          int mb_row,
+                          int mb_col,
+                          MACROBLOCK  *x,
+                          MACROBLOCKD *xd,
+                          TOKENEXTRA **tp,
+                          int *totalrate,
+                          int *totaldist) {
+  int i;
+  int map_index;
+  int recon_yoffset, recon_uvoffset;
+  int ref_fb_idx = cm->lst_fb_idx;
+  int dst_fb_idx = cm->new_fb_idx;
+  int recon_y_stride = cm->yv12_fb[ref_fb_idx].y_stride;
+  int recon_uv_stride = cm->yv12_fb[ref_fb_idx].uv_stride;
+  ENTROPY_CONTEXT_PLANES left_context[2];
+  ENTROPY_CONTEXT_PLANES above_context[2];
+  ENTROPY_CONTEXT_PLANES *initial_above_context_ptr = cm->above_context
+                                                      + mb_col;
+
+  // Offsets to move pointers from MB to MB within a SB in raster order
+  int row_delta[4] = { 0, +1,  0, -1};
+  int col_delta[4] = { +1, -1, +1, +1};
+
+  /* Function should not modify L & A contexts; save and restore on exit */
+  vpx_memcpy(left_context,
+             cm->left_context,
+             sizeof(left_context));
+  vpx_memcpy(above_context,
+             initial_above_context_ptr,
+             sizeof(above_context));
+
+  /* Encode MBs in raster order within the SB */
+  for (i = 0; i < 4; i++) {
+    int dy = row_delta[i];
+    int dx = col_delta[i];
+    int offset_unextended = dy * cm->mb_cols + dx;
+    int offset_extended   = dy * xd->mode_info_stride + dx;
+    MB_MODE_INFO * mbmi = &xd->mode_info_context->mbmi;
+
+    // TODO Many of the index items here can be computed more efficiently!
+
+    if ((mb_row >= cm->mb_rows) || (mb_col >= cm->mb_cols)) {
+      // MB lies outside frame, move on
+      mb_row += dy;
+      mb_col += dx;
+
+      // Update pointers
+      x->src.y_buffer += 16 * (dx + dy * x->src.y_stride);
+      x->src.u_buffer += 8  * (dx + dy * x->src.uv_stride);
+      x->src.v_buffer += 8  * (dx + dy * x->src.uv_stride);
+
+      x->gf_active_ptr += offset_unextended;
+      x->partition_info += offset_extended;
+      xd->mode_info_context += offset_extended;
+      xd->prev_mode_info_context += offset_extended;
+#if CONFIG_DEBUG
+      assert((xd->prev_mode_info_context - cpi->common.prev_mip) ==
+             (xd->mode_info_context - cpi->common.mip));
+#endif
+      continue;
+    }
+
+    // Index of the MB in the SB 0..3
+    xd->mb_index = i;
+
+    map_index = (mb_row * cpi->common.mb_cols) + mb_col;
+    x->mb_activity_ptr = &cpi->mb_activity_map[map_index];
+
+    // set above context pointer
+    xd->above_context = cm->above_context + mb_col;
+
+    // Restore the appropriate left context depending on which
+    // row in the SB the MB is situated
+    xd->left_context = cm->left_context + (i >> 1);
+
+    // Set up distance of MB to edge of frame in 1/8th pel units
+    xd->mb_to_top_edge    = -((mb_row * 16) << 3);
+    xd->mb_to_left_edge   = -((mb_col * 16) << 3);
+    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;
+
+    // Set up limit values for MV components to prevent them from
+    // extending beyond the UMV borders assuming 16x16 block size
+    x->mv_row_min = -((mb_row * 16) + VP9BORDERINPIXELS - VP9_INTERP_EXTEND);
+    x->mv_col_min = -((mb_col * 16) + VP9BORDERINPIXELS - VP9_INTERP_EXTEND);
+    x->mv_row_max = ((cm->mb_rows - mb_row) * 16 +
+                     (VP9BORDERINPIXELS - 16 - VP9_INTERP_EXTEND));
+    x->mv_col_max = ((cm->mb_cols - mb_col) * 16 +
+                     (VP9BORDERINPIXELS - 16 - VP9_INTERP_EXTEND));
+
+    xd->up_available   = (mb_row != 0);
+    xd->left_available = (mb_col != 0);
+
+    recon_yoffset  = (mb_row * recon_y_stride * 16) + (mb_col * 16);
+    recon_uvoffset = (mb_row * recon_uv_stride * 8) + (mb_col *  8);
+
+    xd->dst.y_buffer = cm->yv12_fb[dst_fb_idx].y_buffer + recon_yoffset;
+    xd->dst.u_buffer = cm->yv12_fb[dst_fb_idx].u_buffer + recon_uvoffset;
+    xd->dst.v_buffer = cm->yv12_fb[dst_fb_idx].v_buffer + recon_uvoffset;
+
+#if !CONFIG_SUPERBLOCKS
+    // Copy current MB to a work buffer
+    vp9_copy_mem16x16(x->src.y_buffer, x->src.y_stride, x->thismb, 16);
+#endif
+
+    x->rddiv = cpi->RDDIV;
+    x->rdmult = cpi->RDMULT;
+
+    if (cpi->oxcf.tuning == VP8_TUNE_SSIM)
+      vp9_activity_masking(cpi, x);
+
+    // Is segmentation enabled
+    if (xd->segmentation_enabled) {
+      // Code to set segment id in xd->mbmi.segment_id
+      if (xd->update_mb_segmentation_map)
+        mbmi->segment_id = cpi->segmentation_map[map_index];
+      else
+        mbmi->segment_id = cm->last_frame_seg_map[map_index];
+      if (mbmi->segment_id > 3)
+        mbmi->segment_id = 0;
+
+      vp9_mb_init_quantizer(cpi, x);
+    } else
+      // Set to Segment 0 by default
+      mbmi->segment_id = 0;
+
+    x->active_ptr = cpi->active_map + map_index;
+
+#if CONFIG_SUPERBLOCKS
+    xd->mode_info_context->mbmi.encoded_as_sb = 0;
+#endif
+
+    cpi->update_context = 0;    // TODO Do we need this now??
+
+    vp9_intra_prediction_down_copy(xd);
+
+#ifdef ENC_DEBUG
+      enc_debug = (cpi->common.current_video_frame == 46 &&
+                   mb_row == 5 && mb_col == 2);
+#endif
+    // Find best coding mode & reconstruct the MB so it is available
+    // as a predictor for MBs that follow in the SB
+    if (cm->frame_type == KEY_FRAME) {
+      int r, d;
+#ifdef ENC_DEBUG
+      if (enc_debug)
+        printf("intra pick_mb_modes %d %d\n", mb_row, mb_col);
+#endif
+      vp9_rd_pick_intra_mode(cpi, x, &r, &d);
+      *totalrate += r;
+      *totaldist += d;
+
+      // Dummy encode, do not do the tokenization
+      encode_macroblock(cpi, x, tp,
+                        recon_yoffset, recon_uvoffset, 0, mb_col, mb_row);
+      // Note the encoder may have changed the segment_id
+
+      // Save the coding context
+      vpx_memcpy(&x->mb_context[i].mic, xd->mode_info_context,
+                 sizeof(MODE_INFO));
+    } else {
+      int seg_id, r, d;
+
+      if (xd->segmentation_enabled && cpi->seg0_cnt > 0 &&
+          !vp9_segfeature_active(xd, 0, SEG_LVL_REF_FRAME) &&
+          vp9_segfeature_active(xd, 1, SEG_LVL_REF_FRAME) &&
+          vp9_check_segref(xd, 1, INTRA_FRAME)  +
+          vp9_check_segref(xd, 1, LAST_FRAME)   +
+          vp9_check_segref(xd, 1, GOLDEN_FRAME) +
+          vp9_check_segref(xd, 1, ALTREF_FRAME) == 1) {
+        cpi->seg0_progress = (cpi->seg0_idx << 16) / cpi->seg0_cnt;
+      } else {
+        cpi->seg0_progress = (((mb_col & ~1) * 2 + (mb_row & ~1) * cm->mb_cols + i) << 16) / cm->MBs;
+      }
+
+#ifdef ENC_DEBUG
+      if (enc_debug)
+        printf("inter pick_mb_modes %d %d\n", mb_row, mb_col);
+#endif
+      vp9_pick_mode_inter_macroblock(cpi, x, recon_yoffset,
+                                     recon_uvoffset, &r, &d);
+      *totalrate += r;
+      *totaldist += d;
+
+      // Dummy encode, do not do the tokenization
+      encode_macroblock(cpi, x, tp,
+                        recon_yoffset, recon_uvoffset, 0, mb_col, mb_row);
+
+      seg_id = mbmi->segment_id;
+      if (cpi->mb.e_mbd.segmentation_enabled && seg_id == 0) {
+        cpi->seg0_idx++;
+      }
+      if (!xd->segmentation_enabled ||
+          !vp9_segfeature_active(xd, seg_id, SEG_LVL_REF_FRAME) ||
+          vp9_check_segref(xd, seg_id, INTRA_FRAME)  +
+          vp9_check_segref(xd, seg_id, LAST_FRAME)   +
+          vp9_check_segref(xd, seg_id, GOLDEN_FRAME) +
+          vp9_check_segref(xd, seg_id, ALTREF_FRAME) > 1) {
+        // Get the prediction context and status
+        int pred_flag = vp9_get_pred_flag(xd, PRED_REF);
+        int pred_context = vp9_get_pred_context(cm, xd, PRED_REF);
+
+        // Count prediction success
+        cpi->ref_pred_count[pred_context][pred_flag]++;
+      }
+    }
+
+    // Next MB
+    mb_row += dy;
+    mb_col += dx;
+
+    x->src.y_buffer += 16 * (dx + dy * x->src.y_stride);
+    x->src.u_buffer += 8  * (dx + dy * x->src.uv_stride);
+    x->src.v_buffer += 8  * (dx + dy * x->src.uv_stride);
+
+    x->gf_active_ptr += offset_unextended;
+    x->partition_info += offset_extended;
+    xd->mode_info_context += offset_extended;
+    xd->prev_mode_info_context += offset_extended;
+
+#if CONFIG_DEBUG
+    assert((xd->prev_mode_info_context - cpi->common.prev_mip) ==
+           (xd->mode_info_context - cpi->common.mip));
+#endif
+  }
+
+  /* Restore L & A coding context to those in place on entry */
+  vpx_memcpy(cm->left_context,
+             left_context,
+             sizeof(left_context));
+  vpx_memcpy(initial_above_context_ptr,
+             above_context,
+             sizeof(above_context));
+}
+
+#if CONFIG_SUPERBLOCKS
+static void pick_sb_modes (VP9_COMP *cpi,
+                           VP9_COMMON *cm,
+                           int mb_row,
+                           int mb_col,
+                           MACROBLOCK  *x,
+                           MACROBLOCKD *xd,
+                           TOKENEXTRA **tp,
+                           int *totalrate,
+                           int *totaldist)
+{
+  int map_index;
+  int recon_yoffset, recon_uvoffset;
+  int ref_fb_idx = cm->lst_fb_idx;
+  int dst_fb_idx = cm->new_fb_idx;
+  int recon_y_stride = cm->yv12_fb[ref_fb_idx].y_stride;
+  int recon_uv_stride = cm->yv12_fb[ref_fb_idx].uv_stride;
+  ENTROPY_CONTEXT_PLANES left_context[2];
+  ENTROPY_CONTEXT_PLANES above_context[2];
+  ENTROPY_CONTEXT_PLANES *initial_above_context_ptr = cm->above_context
+    + mb_col;
+
+  /* Function should not modify L & A contexts; save and restore on exit */
+  vpx_memcpy (left_context,
+              cm->left_context,
+              sizeof(left_context));
+  vpx_memcpy (above_context,
+              initial_above_context_ptr,
+              sizeof(above_context));
+
+  map_index = (mb_row * cpi->common.mb_cols) + mb_col;
+  x->mb_activity_ptr = &cpi->mb_activity_map[map_index];
+
+  /* set above context pointer */
+  xd->above_context = cm->above_context + mb_col;
+
+  /* Restore the appropriate left context depending on which
+   * row in the SB the MB is situated */
+  xd->left_context = cm->left_context;
+
+  // Set up distance of MB to edge of frame in 1/8th pel units
+  xd->mb_to_top_edge    = -((mb_row * 16) << 3);
+  xd->mb_to_left_edge   = -((mb_col * 16) << 3);
+  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;
+
+  /* Set up limit values for MV components to prevent them from
+   * extending beyond the UMV borders assuming 16x16 block size */
+  x->mv_row_min = -((mb_row * 16) + VP9BORDERINPIXELS - VP9_INTERP_EXTEND);
+  x->mv_col_min = -((mb_col * 16) + VP9BORDERINPIXELS - VP9_INTERP_EXTEND);
+  x->mv_row_max = ((cm->mb_rows - mb_row) * 16 +
+                   (VP9BORDERINPIXELS - 32 - VP9_INTERP_EXTEND));
+  x->mv_col_max = ((cm->mb_cols - mb_col) * 16 +
+                   (VP9BORDERINPIXELS - 32 - VP9_INTERP_EXTEND));
+
+  xd->up_available   = (mb_row != 0);
+  xd->left_available = (mb_col != 0);
+
+  recon_yoffset  = (mb_row * recon_y_stride * 16) + (mb_col * 16);
+  recon_uvoffset = (mb_row * recon_uv_stride * 8) + (mb_col *  8);
+
+  xd->dst.y_buffer = cm->yv12_fb[dst_fb_idx].y_buffer + recon_yoffset;
+  xd->dst.u_buffer = cm->yv12_fb[dst_fb_idx].u_buffer + recon_uvoffset;
+  xd->dst.v_buffer = cm->yv12_fb[dst_fb_idx].v_buffer + recon_uvoffset;
+#if 0 // FIXME
+  /* Copy current MB to a work buffer */
+  vp9_copy_mem16x16(x->src.y_buffer, x->src.y_stride, x->thismb, 16);
+#endif
+  x->rddiv = cpi->RDDIV;
+  x->rdmult = cpi->RDMULT;
+  if(cpi->oxcf.tuning == VP8_TUNE_SSIM)
+    vp9_activity_masking(cpi, x);
+  /* Is segmentation enabled */
+  if (xd->segmentation_enabled)
+  {
+    /* Code to set segment id in xd->mbmi.segment_id */
+    if (xd->update_mb_segmentation_map)
+      xd->mode_info_context->mbmi.segment_id =
+            cpi->segmentation_map[map_index] &&
+            cpi->segmentation_map[map_index + 1] &&
+            cpi->segmentation_map[map_index + cm->mb_cols] &&
+            cpi->segmentation_map[map_index + cm->mb_cols + 1];
+    else
+      xd->mode_info_context->mbmi.segment_id =
+            cm->last_frame_seg_map[map_index] &&
+            cm->last_frame_seg_map[map_index + 1] &&
+            cm->last_frame_seg_map[map_index + cm->mb_cols] &&
+            cm->last_frame_seg_map[map_index + cm->mb_cols + 1];
+    if (xd->mode_info_context->mbmi.segment_id > 3)
+      xd->mode_info_context->mbmi.segment_id = 0;
+
+    vp9_mb_init_quantizer(cpi, x);
+  }
+  else
+    /* Set to Segment 0 by default */
+    xd->mode_info_context->mbmi.segment_id = 0;
+
+  x->active_ptr = cpi->active_map + map_index;
+
+  cpi->update_context = 0;    // TODO Do we need this now??
+
+  /* Find best coding mode & reconstruct the MB so it is available
+   * as a predictor for MBs that follow in the SB */
+  if (cm->frame_type == KEY_FRAME)
+  {
+    vp9_rd_pick_intra_mode_sb(cpi, x,
+                              totalrate,
+                              totaldist);
+
+    /* Save the coding context */
+    vpx_memcpy(&x->sb_context[0].mic, xd->mode_info_context,
+               sizeof(MODE_INFO));
+  } else {
+    if (xd->segmentation_enabled && cpi->seg0_cnt > 0 &&
+        !vp9_segfeature_active(xd, 0, SEG_LVL_REF_FRAME) &&
+        vp9_segfeature_active(xd, 1, SEG_LVL_REF_FRAME) &&
+        vp9_check_segref(xd, 1, INTRA_FRAME)  +
+        vp9_check_segref(xd, 1, LAST_FRAME)   +
+        vp9_check_segref(xd, 1, GOLDEN_FRAME) +
+        vp9_check_segref(xd, 1, ALTREF_FRAME) == 1) {
+      cpi->seg0_progress = (cpi->seg0_idx << 16) / cpi->seg0_cnt;
+    } else {
+      cpi->seg0_progress =
+        (((mb_col & ~1) * 2 + (mb_row & ~1) * cm->mb_cols) << 16) / cm->MBs;
+    }
+
+    vp9_rd_pick_inter_mode_sb(cpi, x,
+                              recon_yoffset,
+                              recon_uvoffset,
+                              totalrate,
+                              totaldist);
+  }
+
+  /* Restore L & A coding context to those in place on entry */
+  vpx_memcpy (cm->left_context,
+              left_context,
+              sizeof(left_context));
+  vpx_memcpy (initial_above_context_ptr,
+              above_context,
+              sizeof(above_context));
+}
+#endif
+
+static void encode_sb(VP9_COMP *cpi,
+                      VP9_COMMON *cm,
+                      int mbrow,
+                      int mbcol,
+                      MACROBLOCK  *x,
+                      MACROBLOCKD *xd,
+                      TOKENEXTRA **tp) {
+  int i;
+  int map_index;
+  int mb_row, mb_col;
+  int recon_yoffset, recon_uvoffset;
+  int ref_fb_idx = cm->lst_fb_idx;
+  int dst_fb_idx = cm->new_fb_idx;
+  int recon_y_stride = cm->yv12_fb[ref_fb_idx].y_stride;
+  int recon_uv_stride = cm->yv12_fb[ref_fb_idx].uv_stride;
+  int row_delta[4] = { 0, +1,  0, -1};
+  int col_delta[4] = { +1, -1, +1, +1};
+
+  mb_row = mbrow;
+  mb_col = mbcol;
+
+  /* Encode MBs in raster order within the SB */
+  for (i = 0; i < 4; i++) {
+    int dy = row_delta[i];
+    int dx = col_delta[i];
+    int offset_extended   = dy * xd->mode_info_stride + dx;
+    int offset_unextended = dy * cm->mb_cols + dx;
+    MB_MODE_INFO * mbmi = &xd->mode_info_context->mbmi;
+
+    if ((mb_row >= cm->mb_rows) || (mb_col >= cm->mb_cols)) {
+      // MB lies outside frame, move on
+      mb_row += dy;
+      mb_col += dx;
+
+      x->src.y_buffer += 16 * (dx + dy * x->src.y_stride);
+      x->src.u_buffer += 8  * (dx + dy * x->src.uv_stride);
+      x->src.v_buffer += 8  * (dx + dy * x->src.uv_stride);
+
+      x->gf_active_ptr      += offset_unextended;
+      x->partition_info     += offset_extended;
+      xd->mode_info_context += offset_extended;
+      xd->prev_mode_info_context += offset_extended;
+
+#if CONFIG_DEBUG
+      assert((xd->prev_mode_info_context - cpi->common.prev_mip) ==
+             (xd->mode_info_context - cpi->common.mip));
+#endif
+      continue;
+    }
+
+    xd->mb_index = i;
+
+    // Restore MB state to that when it was picked
+#if CONFIG_SUPERBLOCKS
+    if (xd->mode_info_context->mbmi.encoded_as_sb) {
+      update_state(cpi, x, &x->sb_context[i]);
+      cpi->sb_count++;
+    } else
+#endif
+      update_state(cpi, x, &x->mb_context[i]);
+
+    map_index = (mb_row * cpi->common.mb_cols) + mb_col;
+    x->mb_activity_ptr = &cpi->mb_activity_map[map_index];
+
+    // reset above block coeffs
+    xd->above_context = cm->above_context + mb_col;
+    xd->left_context  = cm->left_context + (i >> 1);
+
+    // Set up distance of MB to edge of the frame in 1/8th pel units
+    // Set up limit values for MV components to prevent them from
+    // extending beyond the UMV borders assuming 32x32 block size
+    x->mv_row_min = -((mb_row * 16) + VP9BORDERINPIXELS - VP9_INTERP_EXTEND);
+    x->mv_col_min = -((mb_col * 16) + VP9BORDERINPIXELS - VP9_INTERP_EXTEND);
+
+    xd->mb_to_top_edge    = -((mb_row * 16) << 3);
+    xd->mb_to_left_edge   = -((mb_col * 16) << 3);
+
+#if CONFIG_SUPERBLOCKS
+    if (xd->mode_info_context->mbmi.encoded_as_sb) {
+      x->mv_row_max = ((cm->mb_rows - mb_row) * 16 +
+                       (VP9BORDERINPIXELS - 32 - VP9_INTERP_EXTEND));
+      x->mv_col_max = ((cm->mb_cols - mb_col) * 16 +
+                       (VP9BORDERINPIXELS - 32 - VP9_INTERP_EXTEND));
+
+      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
+      x->mv_row_max = ((cm->mb_rows - mb_row) * 16 +
+                       (VP9BORDERINPIXELS - 16 - VP9_INTERP_EXTEND));
+      x->mv_col_max = ((cm->mb_cols - mb_col) * 16 +
+                       (VP9BORDERINPIXELS - 16 - VP9_INTERP_EXTEND));
+
+      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
+
+    xd->up_available = (mb_row != 0);
+    xd->left_available = (mb_col != 0);
+
+    recon_yoffset = (mb_row * recon_y_stride * 16) + (mb_col * 16);
+    recon_uvoffset = (mb_row * recon_uv_stride * 8) + (mb_col * 8);
+
+    xd->dst.y_buffer = cm->yv12_fb[dst_fb_idx].y_buffer + recon_yoffset;
+    xd->dst.u_buffer = cm->yv12_fb[dst_fb_idx].u_buffer + recon_uvoffset;
+    xd->dst.v_buffer = cm->yv12_fb[dst_fb_idx].v_buffer + recon_uvoffset;
+
+#if !CONFIG_SUPERBLOCKS
+    // Copy current MB to a work buffer
+    vp9_copy_mem16x16(x->src.y_buffer, x->src.y_stride, x->thismb, 16);
+#endif
+
+    if (cpi->oxcf.tuning == VP8_TUNE_SSIM)
+      vp9_activity_masking(cpi, x);
+
+    // Is segmentation enabled
+    if (xd->segmentation_enabled) {
+      vp9_mb_init_quantizer(cpi, x);
+    }
+
+    x->active_ptr = cpi->active_map + map_index;
+
+    cpi->update_context = 0;
+
+#if CONFIG_SUPERBLOCKS
+    if (!xd->mode_info_context->mbmi.encoded_as_sb)
+#endif
+      vp9_intra_prediction_down_copy(xd);
+
+    if (cm->frame_type == KEY_FRAME) {
+#if CONFIG_SUPERBLOCKS
+      if (xd->mode_info_context->mbmi.encoded_as_sb)
+        encode_superblock(cpi, x, tp, recon_yoffset, recon_uvoffset,
+                          mb_col, mb_row);
+      else
+#endif
+        encode_macroblock(cpi, x, tp, recon_yoffset, recon_uvoffset, 1,
+                          mb_col, mb_row);
+        // Note the encoder may have changed the segment_id
+
+#ifdef MODE_STATS
+      y_modes[mbmi->mode]++;
+#endif
+    } else {
+      unsigned char *segment_id;
+      int seg_ref_active;
+
+      if (xd->mode_info_context->mbmi.ref_frame) {
+        unsigned char pred_context;
+
+        pred_context = vp9_get_pred_context(cm, xd, PRED_COMP);
+
+        if (xd->mode_info_context->mbmi.second_ref_frame <= INTRA_FRAME)
+          cpi->single_pred_count[pred_context]++;
+        else
+          cpi->comp_pred_count[pred_context]++;
+      }
+
+#if CONFIG_SUPERBLOCKS
+      if (xd->mode_info_context->mbmi.encoded_as_sb)
+        encode_superblock(cpi, x, tp, recon_yoffset, recon_uvoffset,
+                          mb_col, mb_row);
+      else
+#endif
+        encode_macroblock(cpi, x, tp, recon_yoffset, recon_uvoffset, 1,
+                          mb_col, mb_row);
+        // Note the encoder may have changed the segment_id
+
+#ifdef MODE_STATS
+      inter_y_modes[mbmi->mode]++;
+
+      if (mbmi->mode == SPLITMV) {
+        int b;
+
+        for (b = 0; b < x->partition_info->count; b++) {
+          inter_b_modes[x->partition_info->bmi[b].mode]++;
+        }
+      }
+
+#endif
+
+      // If we have just a single reference frame coded for a segment then
+      // exclude from the reference frame counts used to work out
+      // probabilities. NOTE: At the moment we dont support custom trees
+      // for the reference frame coding for each segment but this is a
+      // possible future action.
+      segment_id = &mbmi->segment_id;
+      seg_ref_active = vp9_segfeature_active(xd, *segment_id,
+                                             SEG_LVL_REF_FRAME);
+      if (!seg_ref_active ||
+          ((vp9_check_segref(xd, *segment_id, INTRA_FRAME) +
+            vp9_check_segref(xd, *segment_id, LAST_FRAME) +
+            vp9_check_segref(xd, *segment_id, GOLDEN_FRAME) +
+            vp9_check_segref(xd, *segment_id, ALTREF_FRAME)) > 1)) {
+        {
+          cpi->count_mb_ref_frame_usage[mbmi->ref_frame]++;
+        }
+      }
+
+      // Count of last ref frame 0,0 usage
+      if ((mbmi->mode == ZEROMV) && (mbmi->ref_frame == LAST_FRAME))
+        cpi->inter_zz_count++;
+    }
+
+#if CONFIG_SUPERBLOCKS
+    if (xd->mode_info_context->mbmi.encoded_as_sb) {
+      x->src.y_buffer += 32;
+      x->src.u_buffer += 16;
+      x->src.v_buffer += 16;
+
+      x->gf_active_ptr      += 2;
+      x->partition_info     += 2;
+      xd->mode_info_context += 2;
+      xd->prev_mode_info_context += 2;
+
+      (*tp)->Token = EOSB_TOKEN;
+      (*tp)++;
+      if (mb_row < cm->mb_rows) cpi->tplist[mb_row].stop = *tp;
+      break;
+    }
+#endif
+
+    // Next MB
+    mb_row += dy;
+    mb_col += dx;
+
+    x->src.y_buffer += 16 * (dx + dy * x->src.y_stride);
+    x->src.u_buffer += 8  * (dx + dy * x->src.uv_stride);
+    x->src.v_buffer += 8  * (dx + dy * x->src.uv_stride);
+
+    x->gf_active_ptr      += offset_unextended;
+    x->partition_info     += offset_extended;
+    xd->mode_info_context += offset_extended;
+    xd->prev_mode_info_context += offset_extended;
+
+#if CONFIG_DEBUG
+    assert((xd->prev_mode_info_context - cpi->common.prev_mip) ==
+           (xd->mode_info_context - cpi->common.mip));
+#endif
+    (*tp)->Token = EOSB_TOKEN;
+    (*tp)++;
+    if (mb_row < cm->mb_rows) cpi->tplist[mb_row].stop = *tp;
+  }
+
+  // debug output
+#if DBG_PRNT_SEGMAP
+  {
+    FILE *statsfile;
+    statsfile = fopen("segmap2.stt", "a");
+    fprintf(statsfile, "\n");
+    fclose(statsfile);
+  }
+#endif
+}
+
+static
+void encode_sb_row(VP9_COMP *cpi,
+                   VP9_COMMON *cm,
+                   int mb_row,
+                   MACROBLOCK  *x,
+                   MACROBLOCKD *xd,
+                   TOKENEXTRA **tp,
+                   int *totalrate) {
+  int mb_col;
+  int mb_cols = cm->mb_cols;
+
+  // Initialize the left context for the new SB row
+  vpx_memset(cm->left_context, 0, sizeof(cm->left_context));
+
+  // Code each SB in the row
+  for (mb_col = 0; mb_col < mb_cols; mb_col += 2) {
+    int mb_rate = 0, mb_dist = 0;
+#if CONFIG_SUPERBLOCKS
+    int sb_rate = INT_MAX, sb_dist;
+#endif
+
+#if CONFIG_DEBUG
+    MODE_INFO *mic = xd->mode_info_context;
+    PARTITION_INFO *pi = x->partition_info;
+    signed char  *gfa = x->gf_active_ptr;
+    unsigned char *yb = x->src.y_buffer;
+    unsigned char *ub = x->src.u_buffer;
+    unsigned char *vb = x->src.v_buffer;
+#endif
+
+#if CONFIG_SUPERBLOCKS
+    // Pick modes assuming the SB is coded as 4 independent MBs
+    xd->mode_info_context->mbmi.encoded_as_sb = 0;
+#endif
+    pick_mb_modes(cpi, cm, mb_row, mb_col, x, xd, tp, &mb_rate, &mb_dist);
+#if CONFIG_SUPERBLOCKS
+    mb_rate += vp9_cost_bit(cm->sb_coded, 0);
+#endif
+
+    x->src.y_buffer -= 32;
+    x->src.u_buffer -= 16;
+    x->src.v_buffer -= 16;
+
+    x->gf_active_ptr -= 2;
+    x->partition_info -= 2;
+    xd->mode_info_context -= 2;
+    xd->prev_mode_info_context -= 2;
+
+#if CONFIG_DEBUG
+    assert(x->gf_active_ptr == gfa);
+    assert(x->partition_info == pi);
+    assert(xd->mode_info_context == mic);
+    assert(x->src.y_buffer == yb);
+    assert(x->src.u_buffer == ub);
+    assert(x->src.v_buffer == vb);
+#endif
+
+#if CONFIG_SUPERBLOCKS
+    if (!(((    mb_cols & 1) && mb_col ==     mb_cols - 1) ||
+          ((cm->mb_rows & 1) && mb_row == cm->mb_rows - 1))) {
+      /* Pick a mode assuming that it applies to all 4 of the MBs in the SB */
+      xd->mode_info_context->mbmi.encoded_as_sb = 1;
+      pick_sb_modes(cpi, cm, mb_row, mb_col, x, xd, tp, &sb_rate, &sb_dist);
+      sb_rate += vp9_cost_bit(cm->sb_coded, 1);
+    }
+
+    /* Decide whether to encode as a SB or 4xMBs */
+    if (sb_rate < INT_MAX &&
+        RDCOST(x->rdmult, x->rddiv, sb_rate, sb_dist) <
+          RDCOST(x->rdmult, x->rddiv, mb_rate, mb_dist)) {
+      xd->mode_info_context->mbmi.encoded_as_sb = 1;
+      xd->mode_info_context[1].mbmi.encoded_as_sb = 1;
+      xd->mode_info_context[cm->mode_info_stride].mbmi.encoded_as_sb = 1;
+      xd->mode_info_context[1 + cm->mode_info_stride].mbmi.encoded_as_sb = 1;
+      *totalrate += sb_rate;
+    } else
+#endif
+    {
+#if CONFIG_SUPERBLOCKS
+      xd->mode_info_context->mbmi.encoded_as_sb = 0;
+      if (cm->mb_cols - 1 > mb_col)
+        xd->mode_info_context[1].mbmi.encoded_as_sb = 0;
+      if (cm->mb_rows - 1 > mb_row) {
+        xd->mode_info_context[cm->mode_info_stride].mbmi.encoded_as_sb = 0;
+        if (cm->mb_cols - 1 > mb_col)
+          xd->mode_info_context[1 + cm->mode_info_stride].mbmi.encoded_as_sb = 0;
+      }
+#endif
+      *totalrate += mb_rate;
+    }
+
+    /* Encode SB using best computed mode(s) */
+    encode_sb(cpi, cm, mb_row, mb_col, x, xd, tp);
+
+#if CONFIG_DEBUG
+    assert(x->gf_active_ptr == gfa + 2);
+    assert(x->partition_info == pi + 2);
+    assert(xd->mode_info_context == mic + 2);
+    assert(x->src.y_buffer == yb + 32);
+    assert(x->src.u_buffer == ub + 16);
+    assert(x->src.v_buffer == vb + 16);
+#endif
+  }
+
+  // this is to account for the border
+  x->gf_active_ptr += mb_cols - (mb_cols & 0x1);
+  x->partition_info += xd->mode_info_stride + 1 - (mb_cols & 0x1);
+  xd->mode_info_context += xd->mode_info_stride + 1 - (mb_cols & 0x1);
+  xd->prev_mode_info_context += xd->mode_info_stride + 1 - (mb_cols & 0x1);
+
+#if CONFIG_DEBUG
+  assert((xd->prev_mode_info_context - cpi->common.prev_mip) ==
+         (xd->mode_info_context - cpi->common.mip));
+#endif
+}
+
+static void init_encode_frame_mb_context(VP9_COMP *cpi) {
+  MACROBLOCK *const x = &cpi->mb;
+  VP9_COMMON *const cm = &cpi->common;
+  MACROBLOCKD *const xd = &x->e_mbd;
+
+  // GF active flags data structure
+  x->gf_active_ptr = (signed char *)cpi->gf_active_flags;
+
+  // Activity map pointer
+  x->mb_activity_ptr = cpi->mb_activity_map;
+
+  x->act_zbin_adj = 0;
+  cpi->seg0_idx = 0;
+  vpx_memset(cpi->ref_pred_count, 0, sizeof(cpi->ref_pred_count));
+
+  x->partition_info = x->pi;
+
+  xd->mode_info_context = cm->mi;
+  xd->mode_info_stride = cm->mode_info_stride;
+  xd->prev_mode_info_context = cm->prev_mi;
+
+  xd->frame_type = cm->frame_type;
+
+  xd->frames_since_golden = cm->frames_since_golden;
+  xd->frames_till_alt_ref_frame = cm->frames_till_alt_ref_frame;
+
+  // reset intra mode contexts
+  if (cm->frame_type == KEY_FRAME)
+    vp9_init_mbmode_probs(cm);
+
+  // Copy data over into macro block data structures.
+  x->src = * cpi->Source;
+  xd->pre = cm->yv12_fb[cm->lst_fb_idx];
+  xd->dst = cm->yv12_fb[cm->new_fb_idx];
+
+  // set up frame for intra coded blocks
+  vp9_setup_intra_recon(&cm->yv12_fb[cm->new_fb_idx]);
+
+  vp9_build_block_offsets(x);
+
+  vp9_setup_block_dptrs(&x->e_mbd);
+
+  vp9_setup_block_ptrs(x);
+
+  xd->mode_info_context->mbmi.mode = DC_PRED;
+  xd->mode_info_context->mbmi.uv_mode = DC_PRED;
+
+  vp9_zero(cpi->count_mb_ref_frame_usage)
+  vp9_zero(cpi->bmode_count)
+  vp9_zero(cpi->ymode_count)
+  vp9_zero(cpi->i8x8_mode_count)
+  vp9_zero(cpi->y_uv_mode_count)
+  vp9_zero(cpi->sub_mv_ref_count)
+  vp9_zero(cpi->mbsplit_count)
+  vp9_zero(cpi->common.fc.mv_ref_ct)
+#if CONFIG_SUPERBLOCKS
+  vp9_zero(cpi->sb_ymode_count)
+  cpi->sb_count = 0;
+#endif
+#if CONFIG_COMP_INTERINTRA_PRED
+  vp9_zero(cpi->interintra_count);
+  vp9_zero(cpi->interintra_select_count);
+#endif
+
+  vpx_memset(cm->above_context, 0,
+             sizeof(ENTROPY_CONTEXT_PLANES) * cm->mb_cols);
+
+  xd->fullpixel_mask = 0xffffffff;
+  if (cm->full_pixel)
+    xd->fullpixel_mask = 0xfffffff8;
+}
+
+static void encode_frame_internal(VP9_COMP *cpi) {
+  int mb_row;
+  MACROBLOCK *const x = &cpi->mb;
+  VP9_COMMON *const cm = &cpi->common;
+  MACROBLOCKD *const xd = &x->e_mbd;
+
+  TOKENEXTRA *tp = cpi->tok;
+  int totalrate;
+
+  // printf("encode_frame_internal frame %d (%d)\n",
+  //        cpi->common.current_video_frame, cpi->common.show_frame);
+
+  // Compute a modified set of reference frame probabilities to use when
+  // prediction fails. These are based on the current general estimates for
+  // this frame which may be updated with each iteration of the recode loop.
+  vp9_compute_mod_refprobs(cm);
+
+#if CONFIG_NEW_MVREF
+  // temp stats reset
+  vp9_zero( cpi->best_ref_index_counts );
+#endif
+
+// debug output
+#if DBG_PRNT_SEGMAP
+  {
+    FILE *statsfile;
+    statsfile = fopen("segmap2.stt", "a");
+    fprintf(statsfile, "\n");
+    fclose(statsfile);
+  }
+#endif
+
+  totalrate = 0;
+
+  // Functions setup for all frame types so we can use MC in AltRef
+  vp9_setup_interp_filters(xd, cm->mcomp_filter_type, cm);
+
+  // Reset frame count of inter 0,0 motion vector usage.
+  cpi->inter_zz_count = 0;
+
+  cpi->prediction_error = 0;
+  cpi->intra_error = 0;
+  cpi->skip_true_count[0] = cpi->skip_true_count[1] = cpi->skip_true_count[2] = 0;
+  cpi->skip_false_count[0] = cpi->skip_false_count[1] = cpi->skip_false_count[2] = 0;
+
+#if CONFIG_PRED_FILTER
+  if (cm->current_video_frame == 0) {
+    // Initially assume that we'll signal the prediction filter
+    // state at the frame level and that it is off.
+    cpi->common.pred_filter_mode = 0;
+    cpi->common.prob_pred_filter_off = 128;
+  }
+  cpi->pred_filter_on_count = 0;
+  cpi->pred_filter_off_count = 0;
+#endif
+  vp9_zero(cpi->switchable_interp_count);
+
+  xd->mode_info_context = cm->mi;
+  xd->prev_mode_info_context = cm->prev_mi;
+
+  vp9_zero(cpi->NMVcount);
+  vp9_zero(cpi->coef_counts);
+  vp9_zero(cpi->hybrid_coef_counts);
+  vp9_zero(cpi->coef_counts_8x8);
+  vp9_zero(cpi->hybrid_coef_counts_8x8);
+  vp9_zero(cpi->coef_counts_16x16);
+  vp9_zero(cpi->hybrid_coef_counts_16x16);
+
+  vp9_frame_init_quantizer(cpi);
+
+  vp9_initialize_rd_consts(cpi, cm->base_qindex + cm->y1dc_delta_q);
+  vp9_initialize_me_consts(cpi, cm->base_qindex);
+
+  if (cpi->oxcf.tuning == VP8_TUNE_SSIM) {
+    // Initialize encode frame context.
+    init_encode_frame_mb_context(cpi);
+
+    // Build a frame level activity map
+    build_activity_map(cpi);
+  }
+
+  // re-initencode frame context.
+  init_encode_frame_mb_context(cpi);
+
+  vpx_memset(cpi->rd_comp_pred_diff, 0, sizeof(cpi->rd_comp_pred_diff));
+  vpx_memset(cpi->single_pred_count, 0, sizeof(cpi->single_pred_count));
+  vpx_memset(cpi->comp_pred_count, 0, sizeof(cpi->comp_pred_count));
+  vpx_memset(cpi->txfm_count, 0, sizeof(cpi->txfm_count));
+  vpx_memset(cpi->txfm_count_8x8p, 0, sizeof(cpi->txfm_count_8x8p));
+  vpx_memset(cpi->rd_tx_select_diff, 0, sizeof(cpi->rd_tx_select_diff));
+  {
+    struct vpx_usec_timer  emr_timer;
+    vpx_usec_timer_start(&emr_timer);
+
+    {
+      // For each row of SBs in the frame
+      for (mb_row = 0; mb_row < cm->mb_rows; mb_row += 2) {
+        int offset = (cm->mb_cols + 1) & ~0x1;
+
+        encode_sb_row(cpi, cm, mb_row, x, xd, &tp, &totalrate);
+
+        // adjust to the next row of SBs
+        x->src.y_buffer += 32 * x->src.y_stride - 16 * offset;
+        x->src.u_buffer += 16 * x->src.uv_stride - 8 * offset;
+        x->src.v_buffer += 16 * x->src.uv_stride - 8 * offset;
+      }
+
+      cpi->tok_count = (unsigned int)(tp - cpi->tok);
+    }
+
+    vpx_usec_timer_mark(&emr_timer);
+    cpi->time_encode_mb_row += vpx_usec_timer_elapsed(&emr_timer);
+
+  }
+
+  // 256 rate units to the bit,
+  // projected_frame_size in units of BYTES
+  cpi->projected_frame_size = totalrate >> 8;
+
+
+#if 0
+  // Keep record of the total distortion this time around for future use
+  cpi->last_frame_distortion = cpi->frame_distortion;
+#endif
+
+}
+
+static int check_dual_ref_flags(VP9_COMP *cpi) {
+  MACROBLOCKD *xd = &cpi->mb.e_mbd;
+  int ref_flags = cpi->ref_frame_flags;
+
+  if (vp9_segfeature_active(xd, 1, SEG_LVL_REF_FRAME)) {
+    if ((ref_flags & (VP9_LAST_FLAG | VP9_GOLD_FLAG)) == (VP9_LAST_FLAG | VP9_GOLD_FLAG) &&
+        vp9_check_segref(xd, 1, LAST_FRAME))
+      return 1;
+    if ((ref_flags & (VP9_GOLD_FLAG | VP9_ALT_FLAG)) == (VP9_GOLD_FLAG | VP9_ALT_FLAG) &&
+        vp9_check_segref(xd, 1, GOLDEN_FRAME))
+      return 1;
+    if ((ref_flags & (VP9_ALT_FLAG  | VP9_LAST_FLAG)) == (VP9_ALT_FLAG  | VP9_LAST_FLAG) &&
+        vp9_check_segref(xd, 1, ALTREF_FRAME))
+      return 1;
+    return 0;
+  } else {
+    return (!!(ref_flags & VP9_GOLD_FLAG) +
+            !!(ref_flags & VP9_LAST_FLAG) +
+            !!(ref_flags & VP9_ALT_FLAG)) >= 2;
+  }
+}
+
+static void reset_skip_txfm_size(VP9_COMP *cpi, TX_SIZE txfm_max) {
+  VP9_COMMON *cm = &cpi->common;
+  int mb_row, mb_col, mis = cm->mode_info_stride, segment_id;
+  MODE_INFO *mi, *mi_ptr = cm->mi;
+#if CONFIG_SUPERBLOCKS
+  int skip;
+  MODE_INFO *sb_mi_ptr = cm->mi, *sb_mi;
+  MB_MODE_INFO *sb_mbmi;
+#endif
+  MB_MODE_INFO *mbmi;
+  MACROBLOCK *x = &cpi->mb;
+  MACROBLOCKD *xd = &x->e_mbd;
+
+  for (mb_row = 0; mb_row < cm->mb_rows; mb_row++, mi_ptr += mis) {
+    mi = mi_ptr;
+#if CONFIG_SUPERBLOCKS
+    sb_mi = sb_mi_ptr;
+#endif
+    for (mb_col = 0; mb_col < cm->mb_cols; mb_col++, mi++) {
+      mbmi = &mi->mbmi;
+#if CONFIG_SUPERBLOCKS
+      sb_mbmi = &sb_mi->mbmi;
+#endif
+      if (mbmi->txfm_size > txfm_max) {
+#if CONFIG_SUPERBLOCKS
+        if (sb_mbmi->encoded_as_sb) {
+          if (!((mb_col & 1) || (mb_row & 1))) {
+            segment_id = mbmi->segment_id;
+            skip = mbmi->mb_skip_coeff;
+            if (mb_col < cm->mb_cols - 1) {
+              segment_id = segment_id && mi[1].mbmi.segment_id;
+              skip = skip && mi[1].mbmi.mb_skip_coeff;
+            }
+            if (mb_row < cm->mb_rows - 1) {
+              segment_id = segment_id &&
+                           mi[cm->mode_info_stride].mbmi.segment_id;
+              skip = skip && mi[cm->mode_info_stride].mbmi.mb_skip_coeff;
+              if (mb_col < cm->mb_cols - 1) {
+                segment_id = segment_id &&
+                             mi[cm->mode_info_stride + 1].mbmi.segment_id;
+                skip = skip && mi[cm->mode_info_stride + 1].mbmi.mb_skip_coeff;
+              }
+            }
+            xd->mode_info_context = mi;
+            assert((vp9_segfeature_active(xd, segment_id, SEG_LVL_EOB) &&
+                    vp9_get_segdata(xd, segment_id, SEG_LVL_EOB) == 0) ||
+                   (cm->mb_no_coeff_skip && skip));
+            mbmi->txfm_size = txfm_max;
+          } else {
+            mbmi->txfm_size = sb_mbmi->txfm_size;
+          }
+        } else {
+#endif
+          segment_id = mbmi->segment_id;
+          xd->mode_info_context = mi;
+          assert((vp9_segfeature_active(xd, segment_id, SEG_LVL_EOB) &&
+                  vp9_get_segdata(xd, segment_id, SEG_LVL_EOB) == 0) ||
+                 (cm->mb_no_coeff_skip && mbmi->mb_skip_coeff));
+          mbmi->txfm_size = txfm_max;
+#if CONFIG_SUPERBLOCKS
+        }
+#endif
+      }
+#if CONFIG_SUPERBLOCKS
+      if (mb_col & 1)
+        sb_mi += 2;
+#endif
+    }
+#if CONFIG_SUPERBLOCKS
+    if (mb_row & 1)
+      sb_mi_ptr += 2 * mis;
+#endif
+  }
+}
+
+void vp9_encode_frame(VP9_COMP *cpi) {
+  if (cpi->sf.RD) {
+    int i, frame_type, pred_type;
+    TXFM_MODE txfm_type;
+
+    /*
+     * This code does a single RD pass over the whole frame assuming
+     * either compound, single or hybrid prediction as per whatever has
+     * worked best for that type of frame in the past.
+     * It also predicts whether another coding mode would have worked
+     * better that this coding mode. If that is the case, it remembers
+     * that for subsequent frames.
+     * It does the same analysis for transform size selection also.
+     */
+    if (cpi->common.frame_type == KEY_FRAME)
+      frame_type = 0;
+    else if (cpi->is_src_frame_alt_ref && cpi->common.refresh_golden_frame)
+      frame_type = 3;
+    else if (cpi->common.refresh_golden_frame || cpi->common.refresh_alt_ref_frame)
+      frame_type = 1;
+    else
+      frame_type = 2;
+
+    /* prediction (compound, single or hybrid) mode selection */
+    if (frame_type == 3)
+      pred_type = SINGLE_PREDICTION_ONLY;
+    else if (cpi->rd_prediction_type_threshes[frame_type][1] >
+                 cpi->rd_prediction_type_threshes[frame_type][0] &&
+             cpi->rd_prediction_type_threshes[frame_type][1] >
+                 cpi->rd_prediction_type_threshes[frame_type][2] &&
+             check_dual_ref_flags(cpi) && cpi->static_mb_pct == 100)
+      pred_type = COMP_PREDICTION_ONLY;
+    else if (cpi->rd_prediction_type_threshes[frame_type][0] >
+                 cpi->rd_prediction_type_threshes[frame_type][2])
+      pred_type = SINGLE_PREDICTION_ONLY;
+    else
+      pred_type = HYBRID_PREDICTION;
+
+    /* transform size (4x4, 8x8, 16x16 or select-per-mb) selection */
+#if CONFIG_LOSSLESS
+    if (cpi->oxcf.lossless) {
+      txfm_type = ONLY_4X4;
+    } else
+#endif
+    /* FIXME (rbultje)
+     * this is a hack (no really), basically to work around the complete
+     * nonsense coefficient cost prediction for keyframes. The probabilities
+     * are reset to defaults, and thus we basically have no idea how expensive
+     * a 4x4 vs. 8x8 will really be. The result is that any estimate at which
+     * of the two is better is utterly bogus.
+     * I'd like to eventually remove this hack, but in order to do that, we
+     * need to move the frame reset code from the frame encode init to the
+     * bitstream write code, or alternatively keep a backup of the previous
+     * keyframe's probabilities as an estimate of what the current keyframe's
+     * coefficient cost distributions may look like. */
+    if (frame_type == 0) {
+      txfm_type = ALLOW_16X16;
+    } else
+#if 0
+    /* FIXME (rbultje)
+     * this code is disabled for a similar reason as the code above; the
+     * problem is that each time we "revert" to 4x4 only (or even 8x8 only),
+     * the coefficient probabilities for 16x16 (and 8x8) start lagging behind,
+     * thus leading to them lagging further behind and not being chosen for
+     * subsequent frames either. This is essentially a local minimum problem
+     * that we can probably fix by estimating real costs more closely within
+     * a frame, perhaps by re-calculating costs on-the-fly as frame encoding
+     * progresses. */
+    if (cpi->rd_tx_select_threshes[frame_type][TX_MODE_SELECT] >
+            cpi->rd_tx_select_threshes[frame_type][ONLY_4X4] &&
+        cpi->rd_tx_select_threshes[frame_type][TX_MODE_SELECT] >
+            cpi->rd_tx_select_threshes[frame_type][ALLOW_16X16] &&
+        cpi->rd_tx_select_threshes[frame_type][TX_MODE_SELECT] >
+            cpi->rd_tx_select_threshes[frame_type][ALLOW_8X8]) {
+      txfm_type = TX_MODE_SELECT;
+    } else if (cpi->rd_tx_select_threshes[frame_type][ONLY_4X4] >
+                  cpi->rd_tx_select_threshes[frame_type][ALLOW_8X8]
+            && cpi->rd_tx_select_threshes[frame_type][ONLY_4X4] >
+                  cpi->rd_tx_select_threshes[frame_type][ALLOW_16X16]
+               ) {
+      txfm_type = ONLY_4X4;
+    } else if (cpi->rd_tx_select_threshes[frame_type][ALLOW_16X16] >=
+                  cpi->rd_tx_select_threshes[frame_type][ALLOW_8X8]) {
+      txfm_type = ALLOW_16X16;
+    } else
+      txfm_type = ALLOW_8X8;
+#else
+    txfm_type = cpi->rd_tx_select_threshes[frame_type][ALLOW_16X16] >=
+                 cpi->rd_tx_select_threshes[frame_type][TX_MODE_SELECT] ?
+    ALLOW_16X16 : TX_MODE_SELECT;
+#endif
+    cpi->common.txfm_mode = txfm_type;
+    if (txfm_type != TX_MODE_SELECT) {
+      cpi->common.prob_tx[0] = 128;
+      cpi->common.prob_tx[1] = 128;
+    }
+    cpi->common.comp_pred_mode = pred_type;
+    encode_frame_internal(cpi);
+
+    for (i = 0; i < NB_PREDICTION_TYPES; ++i) {
+      const int diff = (int)(cpi->rd_comp_pred_diff[i] / cpi->common.MBs);
+      cpi->rd_prediction_type_threshes[frame_type][i] += diff;
+      cpi->rd_prediction_type_threshes[frame_type][i] >>= 1;
+    }
+
+    for (i = 0; i < NB_TXFM_MODES; ++i) {
+      int64_t pd = cpi->rd_tx_select_diff[i];
+      int diff;
+      if (i == TX_MODE_SELECT)
+        pd -= RDCOST(cpi->mb.rdmult, cpi->mb.rddiv, 2048 * (TX_SIZE_MAX - 1), 0);
+      diff = (int)(pd / cpi->common.MBs);
+      cpi->rd_tx_select_threshes[frame_type][i] += diff;
+      cpi->rd_tx_select_threshes[frame_type][i] /= 2;
+    }
+
+    if (cpi->common.comp_pred_mode == HYBRID_PREDICTION) {
+      int single_count_zero = 0;
+      int comp_count_zero = 0;
+
+      for (i = 0; i < COMP_PRED_CONTEXTS; i++) {
+        single_count_zero += cpi->single_pred_count[i];
+        comp_count_zero += cpi->comp_pred_count[i];
+      }
+
+      if (comp_count_zero == 0) {
+        cpi->common.comp_pred_mode = SINGLE_PREDICTION_ONLY;
+      } else if (single_count_zero == 0) {
+        cpi->common.comp_pred_mode = COMP_PREDICTION_ONLY;
+      }
+    }
+
+    if (cpi->common.txfm_mode == TX_MODE_SELECT) {
+      const int count4x4 = cpi->txfm_count[TX_4X4] + cpi->txfm_count_8x8p[TX_4X4];
+      const int count8x8 = cpi->txfm_count[TX_8X8];
+      const int count8x8_8x8p = cpi->txfm_count_8x8p[TX_8X8];
+      const int count16x16 = cpi->txfm_count[TX_16X16];
+
+      if (count4x4 == 0 && count16x16 == 0) {
+        cpi->common.txfm_mode = ALLOW_8X8;
+        reset_skip_txfm_size(cpi, TX_8X8);
+      } else if (count8x8 == 0 && count16x16 == 0 && count8x8_8x8p == 0) {
+        cpi->common.txfm_mode = ONLY_4X4;
+        reset_skip_txfm_size(cpi, TX_4X4);
+      } else if (count8x8 == 0 && count4x4 == 0) {
+        cpi->common.txfm_mode = ALLOW_16X16;
+      }
+    }
+  } else {
+    encode_frame_internal(cpi);
+  }
+
+}
+
+void vp9_setup_block_ptrs(MACROBLOCK *x) {
+  int r, c;
+  int i;
+
+  for (r = 0; r < 4; r++) {
+    for (c = 0; c < 4; c++) {
+      x->block[r * 4 + c].src_diff = x->src_diff + r * 4 * 16 + c * 4;
+    }
+  }
+
+  for (r = 0; r < 2; r++) {
+    for (c = 0; c < 2; c++) {
+      x->block[16 + r * 2 + c].src_diff = x->src_diff + 256 + r * 4 * 8 + c * 4;
+    }
+  }
+
+
+  for (r = 0; r < 2; r++) {
+    for (c = 0; c < 2; c++) {
+      x->block[20 + r * 2 + c].src_diff = x->src_diff + 320 + r * 4 * 8 + c * 4;
+    }
+  }
+
+  x->block[24].src_diff = x->src_diff + 384;
+
+
+  for (i = 0; i < 25; i++) {
+    x->block[i].coeff = x->coeff + i * 16;
+  }
+}
+
+void vp9_build_block_offsets(MACROBLOCK *x) {
+  int block = 0;
+  int br, bc;
+
+  vp9_build_block_doffsets(&x->e_mbd);
+
+#if !CONFIG_SUPERBLOCKS
+  // y blocks
+  x->thismb_ptr = &x->thismb[0];
+  for (br = 0; br < 4; br++) {
+    for (bc = 0; bc < 4; bc++) {
+      BLOCK *this_block = &x->block[block];
+      // this_block->base_src = &x->src.y_buffer;
+      // this_block->src_stride = x->src.y_stride;
+      // this_block->src = 4 * br * this_block->src_stride + 4 * bc;
+      this_block->base_src = &x->thismb_ptr;
+      this_block->src_stride = 16;
+      this_block->src = 4 * br * 16 + 4 * bc;
+      ++block;
+    }
+  }
+#else
+  for (br = 0; br < 4; br++) {
+    for (bc = 0; bc < 4; bc++) {
+      BLOCK *this_block = &x->block[block];
+      // this_block->base_src = &x->src.y_buffer;
+      // this_block->src_stride = x->src.y_stride;
+      // this_block->src = 4 * br * this_block->src_stride + 4 * bc;
+      this_block->base_src = &x->src.y_buffer;
+      this_block->src_stride = x->src.y_stride;
+      this_block->src = 4 * br * this_block->src_stride + 4 * bc;
+      ++block;
+    }
+  }
+#endif
+
+  // u blocks
+  for (br = 0; br < 2; br++) {
+    for (bc = 0; bc < 2; bc++) {
+      BLOCK *this_block = &x->block[block];
+      this_block->base_src = &x->src.u_buffer;
+      this_block->src_stride = x->src.uv_stride;
+      this_block->src = 4 * br * this_block->src_stride + 4 * bc;
+      ++block;
+    }
+  }
+
+  // v blocks
+  for (br = 0; br < 2; br++) {
+    for (bc = 0; bc < 2; bc++) {
+      BLOCK *this_block = &x->block[block];
+      this_block->base_src = &x->src.v_buffer;
+      this_block->src_stride = x->src.uv_stride;
+      this_block->src = 4 * br * this_block->src_stride + 4 * bc;
+      ++block;
+    }
+  }
+}
+
+static void sum_intra_stats(VP9_COMP *cpi, MACROBLOCK *x) {
+  const MACROBLOCKD *xd = &x->e_mbd;
+  const MB_PREDICTION_MODE m = xd->mode_info_context->mbmi.mode;
+  const MB_PREDICTION_MODE uvm = xd->mode_info_context->mbmi.uv_mode;
+
+#ifdef MODE_STATS
+  const int is_key = cpi->common.frame_type == KEY_FRAME;
+
+  ++ (is_key ? uv_modes : inter_uv_modes)[uvm];
+  ++ uv_modes_y[m][uvm];
+
+  if (m == B_PRED) {
+    unsigned int *const bct = is_key ? b_modes : inter_b_modes;
+
+    int b = 0;
+
+    do {
+      ++ bct[xd->block[b].bmi.as_mode.first];
+    } while (++b < 16);
+  }
+
+  if (m == I8X8_PRED) {
+    i8x8_modes[xd->block[0].bmi.as_mode.first]++;
+    i8x8_modes[xd->block[2].bmi.as_mode.first]++;
+    i8x8_modes[xd->block[8].bmi.as_mode.first]++;
+    i8x8_modes[xd->block[10].bmi.as_mode.first]++;
+  }
+#endif
+
+#if CONFIG_SUPERBLOCKS
+  if (xd->mode_info_context->mbmi.encoded_as_sb) {
+    ++cpi->sb_ymode_count[m];
+  } else
+#endif
+    ++cpi->ymode_count[m];
+  if (m != I8X8_PRED)
+    ++cpi->y_uv_mode_count[m][uvm];
+  else {
+    cpi->i8x8_mode_count[xd->block[0].bmi.as_mode.first]++;
+    cpi->i8x8_mode_count[xd->block[2].bmi.as_mode.first]++;
+    cpi->i8x8_mode_count[xd->block[8].bmi.as_mode.first]++;
+    cpi->i8x8_mode_count[xd->block[10].bmi.as_mode.first]++;
+  }
+  if (m == B_PRED) {
+    int b = 0;
+    do {
+      int m = xd->block[b].bmi.as_mode.first;
+#if CONFIG_NEWBINTRAMODES
+      if (m == B_CONTEXT_PRED) m -= CONTEXT_PRED_REPLACEMENTS;
+#endif
+      ++cpi->bmode_count[m];
+    } while (++b < 16);
+  }
+}
+
+// Experimental stub function to create a per MB zbin adjustment based on
+// some previously calculated measure of MB activity.
+static void adjust_act_zbin(VP9_COMP *cpi, MACROBLOCK *x) {
+#if USE_ACT_INDEX
+  x->act_zbin_adj = *(x->mb_activity_ptr);
+#else
+  int64_t a;
+  int64_t b;
+  int64_t act = *(x->mb_activity_ptr);
+
+  // Apply the masking to the RD multiplier.
+  a = act + 4 * cpi->activity_avg;
+  b = 4 * act + cpi->activity_avg;
+
+  if (act > cpi->activity_avg)
+    x->act_zbin_adj = (int)(((int64_t)b + (a >> 1)) / a) - 1;
+  else
+    x->act_zbin_adj = 1 - (int)(((int64_t)a + (b >> 1)) / b);
+#endif
+}
+
+#if CONFIG_SUPERBLOCKS
+static void update_sb_skip_coeff_state(VP9_COMP *cpi,
+                                       MACROBLOCK *x,
+                                       ENTROPY_CONTEXT_PLANES ta[4],
+                                       ENTROPY_CONTEXT_PLANES tl[4],
+                                       TOKENEXTRA *t[4],
+                                       TOKENEXTRA **tp,
+                                       int skip[4])
+{
+  TOKENEXTRA tokens[4][16 * 24];
+  int n_tokens[4], n;
+
+  // if there were no skips, we don't need to do anything
+  if (!skip[0] && !skip[1] && !skip[2] && !skip[3])
+    return;
+
+  // if we don't do coeff skipping for this frame, we don't
+  // need to do anything here
+  if (!cpi->common.mb_no_coeff_skip)
+    return;
+
+  // if all 4 MBs skipped coeff coding, nothing to be done
+  if (skip[0] && skip[1] && skip[2] && skip[3])
+    return;
+
+  // so the situation now is that we want to skip coeffs
+  // for some MBs, but not all, and we didn't code EOB
+  // coefficients for them. However, the skip flag for this
+  // SB will be 0 overall, so we need to insert EOBs in the
+  // middle of the token tree. Do so here.
+  n_tokens[0] = t[1] - t[0];
+  n_tokens[1] = t[2] - t[1];
+  n_tokens[2] = t[3] - t[2];
+  n_tokens[3] = *tp  - t[3];
+  if (n_tokens[0])
+    memcpy(tokens[0], t[0], n_tokens[0] * sizeof(*t[0]));
+  if (n_tokens[1])
+    memcpy(tokens[1], t[1], n_tokens[1] * sizeof(*t[0]));
+  if (n_tokens[2])
+    memcpy(tokens[2], t[2], n_tokens[2] * sizeof(*t[0]));
+  if (n_tokens[3])
+    memcpy(tokens[3], t[3], n_tokens[3] * sizeof(*t[0]));
+
+  // reset pointer, stuff EOBs where necessary
+  *tp = t[0];
+  for (n = 0; n < 4; n++) {
+    if (skip[n]) {
+      x->e_mbd.above_context = &ta[n];
+      x->e_mbd.left_context  = &tl[n];
+      vp9_stuff_mb(cpi, &x->e_mbd, tp, 0);
+    } else {
+      if (n_tokens[n]) {
+        memcpy(*tp, tokens[n], sizeof(*t[0]) * n_tokens[n]);
+      }
+      (*tp) += n_tokens[n];
+    }
+  }
+}
+#endif /* CONFIG_SUPERBLOCKS */
+
+static void encode_macroblock(VP9_COMP *cpi, MACROBLOCK *x,
+                              TOKENEXTRA **t, int recon_yoffset,
+                              int recon_uvoffset, int output_enabled,
+                              int mb_col, int mb_row) {
+  VP9_COMMON *cm = &cpi->common;
+  MACROBLOCKD *const xd = &x->e_mbd;
+  MB_MODE_INFO * mbmi = &xd->mode_info_context->mbmi;
+  unsigned char *segment_id = &mbmi->segment_id;
+  int seg_ref_active;
+  unsigned char ref_pred_flag;
+
+  x->skip = 0;
+#if CONFIG_SUPERBLOCKS
+  assert(!xd->mode_info_context->mbmi.encoded_as_sb);
+#endif
+
+#ifdef ENC_DEBUG
+  enc_debug = (cpi->common.current_video_frame == 46 &&
+               mb_row == 5 && mb_col == 2);
+  if (enc_debug)
+    printf("Encode MB %d %d output %d\n", mb_row, mb_col, output_enabled);
+#endif
+  if (cm->frame_type == KEY_FRAME) {
+    if (cpi->oxcf.tuning == VP8_TUNE_SSIM && output_enabled) {
+      // Adjust the zbin based on this MB rate.
+      adjust_act_zbin(cpi, x);
+      vp9_update_zbin_extra(cpi, x);
+    }
+  } else {
+    vp9_setup_interp_filters(xd, mbmi->interp_filter, cm);
+
+    if (cpi->oxcf.tuning == VP8_TUNE_SSIM) {
+      // Adjust the zbin based on this MB rate.
+      adjust_act_zbin(cpi, x);
+    }
+
+    // Experimental code. Special case for gf and arf zeromv modes.
+    // Increase zbin size to suppress noise
+    cpi->zbin_mode_boost = 0;
+    if (cpi->zbin_mode_boost_enabled) {
+      if (mbmi->ref_frame != INTRA_FRAME) {
+        if (mbmi->mode == ZEROMV) {
+          if (mbmi->ref_frame != LAST_FRAME)
+            cpi->zbin_mode_boost = GF_ZEROMV_ZBIN_BOOST;
+          else
+            cpi->zbin_mode_boost = LF_ZEROMV_ZBIN_BOOST;
+        } else if (mbmi->mode == SPLITMV)
+          cpi->zbin_mode_boost = 0;
+        else
+          cpi->zbin_mode_boost = MV_ZBIN_BOOST;
+      }
+    }
+
+    vp9_update_zbin_extra(cpi, x);
+
+    seg_ref_active = vp9_segfeature_active(xd, *segment_id, SEG_LVL_REF_FRAME);
+
+    // SET VARIOUS PREDICTION FLAGS
+
+    // Did the chosen reference frame match its predicted value.
+    ref_pred_flag = ((mbmi->ref_frame == vp9_get_pred_ref(cm, xd)));
+    vp9_set_pred_flag(xd, PRED_REF, ref_pred_flag);
+  }
+
+  if (mbmi->ref_frame == INTRA_FRAME) {
+#ifdef ENC_DEBUG
+    if (enc_debug) {
+      printf("Mode %d skip %d tx_size %d\n", mbmi->mode, x->skip,
+             mbmi->txfm_size);
+    }
+#endif
+    if (mbmi->mode == B_PRED) {
+      vp9_encode_intra16x16mbuv(x);
+      vp9_encode_intra4x4mby(x);
+    } else if (mbmi->mode == I8X8_PRED) {
+      vp9_encode_intra8x8mby(x);
+      vp9_encode_intra8x8mbuv(x);
+    } else {
+      vp9_encode_intra16x16mbuv(x);
+      vp9_encode_intra16x16mby(x);
+    }
+
+    if (output_enabled)
+      sum_intra_stats(cpi, x);
+  } else {
+    int ref_fb_idx;
+#ifdef ENC_DEBUG
+    if (enc_debug)
+      printf("Mode %d skip %d tx_size %d ref %d ref2 %d mv %d %d interp %d\n",
+             mbmi->mode, x->skip, mbmi->txfm_size,
+             mbmi->ref_frame, mbmi->second_ref_frame,
+             mbmi->mv[0].as_mv.row, mbmi->mv[0].as_mv.col,
+             mbmi->interp_filter);
+#endif
+
+    assert(cm->frame_type != KEY_FRAME);
+
+    if (mbmi->ref_frame == LAST_FRAME)
+      ref_fb_idx = cpi->common.lst_fb_idx;
+    else if (mbmi->ref_frame == GOLDEN_FRAME)
+      ref_fb_idx = cpi->common.gld_fb_idx;
+    else
+      ref_fb_idx = cpi->common.alt_fb_idx;
+
+    xd->pre.y_buffer = cpi->common.yv12_fb[ref_fb_idx].y_buffer + recon_yoffset;
+    xd->pre.u_buffer = cpi->common.yv12_fb[ref_fb_idx].u_buffer + recon_uvoffset;
+    xd->pre.v_buffer = cpi->common.yv12_fb[ref_fb_idx].v_buffer + recon_uvoffset;
+
+    if (mbmi->second_ref_frame > 0) {
+      int second_ref_fb_idx;
+
+      if (mbmi->second_ref_frame == LAST_FRAME)
+        second_ref_fb_idx = cpi->common.lst_fb_idx;
+      else if (mbmi->second_ref_frame == GOLDEN_FRAME)
+        second_ref_fb_idx = cpi->common.gld_fb_idx;
+      else
+        second_ref_fb_idx = cpi->common.alt_fb_idx;
+
+      xd->second_pre.y_buffer = cpi->common.yv12_fb[second_ref_fb_idx].y_buffer +
+                                recon_yoffset;
+      xd->second_pre.u_buffer = cpi->common.yv12_fb[second_ref_fb_idx].u_buffer +
+                                recon_uvoffset;
+      xd->second_pre.v_buffer = cpi->common.yv12_fb[second_ref_fb_idx].v_buffer +
+                                recon_uvoffset;
+    }
+
+    if (!x->skip) {
+      vp9_encode_inter16x16(x);
+
+      // Clear mb_skip_coeff if mb_no_coeff_skip is not set
+      if (!cpi->common.mb_no_coeff_skip)
+        mbmi->mb_skip_coeff = 0;
+
+    } else {
+      vp9_build_1st_inter16x16_predictors_mb(xd,
+                                             xd->dst.y_buffer,
+                                             xd->dst.u_buffer,
+                                             xd->dst.v_buffer,
+                                             xd->dst.y_stride,
+                                             xd->dst.uv_stride);
+      if (xd->mode_info_context->mbmi.second_ref_frame > 0) {
+        vp9_build_2nd_inter16x16_predictors_mb(xd,
+                                               xd->dst.y_buffer,
+                                               xd->dst.u_buffer,
+                                               xd->dst.v_buffer,
+                                               xd->dst.y_stride,
+                                               xd->dst.uv_stride);
+      }
+#if CONFIG_COMP_INTERINTRA_PRED
+      else if (xd->mode_info_context->mbmi.second_ref_frame == INTRA_FRAME) {
+        vp9_build_interintra_16x16_predictors_mb(xd,
+                                                 xd->dst.y_buffer,
+                                                 xd->dst.u_buffer,
+                                                 xd->dst.v_buffer,
+                                                 xd->dst.y_stride,
+                                                 xd->dst.uv_stride);
+      }
+#endif
+    }
+  }
+
+  if (!x->skip) {
+#ifdef ENC_DEBUG
+    if (enc_debug) {
+      int i, j;
+      printf("\n");
+      printf("qcoeff\n");
+      for (i = 0; i < 400; i++) {
+        printf("%3d ", xd->qcoeff[i]);
+        if (i % 16 == 15) printf("\n");
+      }
+      printf("\n");
+      printf("predictor\n");
+      for (i = 0; i < 384; i++) {
+        printf("%3d ", xd->predictor[i]);
+        if (i % 16 == 15) printf("\n");
+      }
+      printf("\n");
+      printf("src_diff\n");
+      for (i = 0; i < 384; i++) {
+        printf("%3d ", x->src_diff[i]);
+        if (i % 16 == 15) printf("\n");
+      }
+      printf("\n");
+      printf("diff\n");
+      for (i = 0; i < 384; i++) {
+        printf("%3d ", xd->block[0].diff[i]);
+        if (i % 16 == 15) printf("\n");
+      }
+      printf("\n");
+      printf("final y\n");
+      for (i = 0; i < 16; i++) {
+        for (j = 0; j < 16; j++)
+          printf("%3d ", xd->dst.y_buffer[i * xd->dst.y_stride + j]);
+        printf("\n");
+      }
+      printf("\n");
+      printf("final u\n");
+      for (i = 0; i < 8; i++) {
+        for (j = 0; j < 8; j++)
+          printf("%3d ", xd->dst.u_buffer[i * xd->dst.uv_stride + j]);
+        printf("\n");
+      }
+      printf("\n");
+      printf("final v\n");
+      for (i = 0; i < 8; i++) {
+        for (j = 0; j < 8; j++)
+          printf("%3d ", xd->dst.v_buffer[i * xd->dst.uv_stride + j]);
+        printf("\n");
+      }
+      fflush(stdout);
+    }
+#endif
+
+    vp9_tokenize_mb(cpi, xd, t, !output_enabled);
+
+  } else {
+    int mb_skip_context =
+      cpi->common.mb_no_coeff_skip ?
+      (x->e_mbd.mode_info_context - 1)->mbmi.mb_skip_coeff +
+      (x->e_mbd.mode_info_context - cpi->common.mode_info_stride)->mbmi.mb_skip_coeff :
+      0;
+    if (cpi->common.mb_no_coeff_skip) {
+      mbmi->mb_skip_coeff = 1;
+      if (output_enabled)
+        cpi->skip_true_count[mb_skip_context]++;
+      vp9_fix_contexts(xd);
+    } else {
+      vp9_stuff_mb(cpi, xd, t, !output_enabled);
+      mbmi->mb_skip_coeff = 0;
+      if (output_enabled)
+        cpi->skip_false_count[mb_skip_context]++;
+    }
+  }
+
+  if (output_enabled) {
+    int segment_id = mbmi->segment_id;
+    if (cpi->common.txfm_mode == TX_MODE_SELECT &&
+        !((cpi->common.mb_no_coeff_skip && mbmi->mb_skip_coeff) ||
+          (vp9_segfeature_active(&x->e_mbd, segment_id, SEG_LVL_EOB) &&
+           vp9_get_segdata(&x->e_mbd, segment_id, SEG_LVL_EOB) == 0))) {
+      if (mbmi->mode != B_PRED && mbmi->mode != I8X8_PRED &&
+          mbmi->mode != SPLITMV) {
+        cpi->txfm_count[mbmi->txfm_size]++;
+      } else if (mbmi->mode == I8X8_PRED ||
+                 (mbmi->mode == SPLITMV &&
+                  mbmi->partitioning != PARTITIONING_4X4)) {
+        cpi->txfm_count_8x8p[mbmi->txfm_size]++;
+      }
+    } else if (mbmi->mode != B_PRED && mbmi->mode != I8X8_PRED &&
+        mbmi->mode != SPLITMV && cpi->common.txfm_mode >= ALLOW_16X16) {
+      mbmi->txfm_size = TX_16X16;
+    } else if (mbmi->mode != B_PRED &&
+               !(mbmi->mode == SPLITMV &&
+                 mbmi->partitioning == PARTITIONING_4X4) &&
+               cpi->common.txfm_mode >= ALLOW_8X8) {
+      mbmi->txfm_size = TX_8X8;
+    } else {
+      mbmi->txfm_size = TX_4X4;
+    }
+  }
+}
+
+#if CONFIG_SUPERBLOCKS
+static void encode_superblock(VP9_COMP *cpi, MACROBLOCK *x,
+                              TOKENEXTRA **t, int recon_yoffset,
+                              int recon_uvoffset, int mb_col, int mb_row) {
+  VP9_COMMON *const cm = &cpi->common;
+  MACROBLOCKD *const xd = &x->e_mbd;
+  const uint8_t *src = x->src.y_buffer;
+  uint8_t *dst = xd->dst.y_buffer;
+  const uint8_t *usrc = x->src.u_buffer;
+  uint8_t *udst = xd->dst.u_buffer;
+  const uint8_t *vsrc = x->src.v_buffer;
+  uint8_t *vdst = xd->dst.v_buffer;
+  int src_y_stride = x->src.y_stride, dst_y_stride = xd->dst.y_stride;
+  int src_uv_stride = x->src.uv_stride, dst_uv_stride = xd->dst.uv_stride;
+  int seg_ref_active;
+  unsigned char ref_pred_flag;
+  int n;
+  TOKENEXTRA *tp[4];
+  int skip[4];
+  MODE_INFO *mi = x->e_mbd.mode_info_context;
+  unsigned int segment_id = mi->mbmi.segment_id;
+  ENTROPY_CONTEXT_PLANES ta[4], tl[4];
+
+  x->skip = 0;
+
+  if (cm->frame_type == KEY_FRAME) {
+    if (cpi->oxcf.tuning == VP8_TUNE_SSIM) {
+      adjust_act_zbin(cpi, x);
+      vp9_update_zbin_extra(cpi, x);
+    }
+  } else {
+    vp9_setup_interp_filters(xd, xd->mode_info_context->mbmi.interp_filter, cm);
+
+    if (cpi->oxcf.tuning == VP8_TUNE_SSIM) {
+      // Adjust the zbin based on this MB rate.
+      adjust_act_zbin(cpi, x);
+    }
+
+    // Experimental code. Special case for gf and arf zeromv modes.
+    // Increase zbin size to suppress noise
+    cpi->zbin_mode_boost = 0;
+    if (cpi->zbin_mode_boost_enabled) {
+      if (xd->mode_info_context->mbmi.ref_frame != INTRA_FRAME) {
+        if (xd->mode_info_context->mbmi.mode == ZEROMV) {
+          if (xd->mode_info_context->mbmi.ref_frame != LAST_FRAME)
+            cpi->zbin_mode_boost = GF_ZEROMV_ZBIN_BOOST;
+          else
+            cpi->zbin_mode_boost = LF_ZEROMV_ZBIN_BOOST;
+        } else if (xd->mode_info_context->mbmi.mode == SPLITMV)
+          cpi->zbin_mode_boost = 0;
+        else
+          cpi->zbin_mode_boost = MV_ZBIN_BOOST;
+      }
+    }
+
+    vp9_update_zbin_extra(cpi, x);
+
+    seg_ref_active = vp9_segfeature_active(xd, segment_id, SEG_LVL_REF_FRAME);
+
+    // SET VARIOUS PREDICTION FLAGS
+
+    // Did the chosen reference frame match its predicted value.
+    ref_pred_flag = ((xd->mode_info_context->mbmi.ref_frame ==
+                      vp9_get_pred_ref(cm, xd)));
+    vp9_set_pred_flag(xd, PRED_REF, ref_pred_flag);
+  }
+
+
+  if (xd->mode_info_context->mbmi.ref_frame == INTRA_FRAME) {
+    vp9_build_intra_predictors_sby_s(&x->e_mbd);
+    vp9_build_intra_predictors_sbuv_s(&x->e_mbd);
+    sum_intra_stats(cpi, x);
+  } else {
+    int ref_fb_idx;
+
+    assert(cm->frame_type != KEY_FRAME);
+
+    if (xd->mode_info_context->mbmi.ref_frame == LAST_FRAME)
+      ref_fb_idx = cpi->common.lst_fb_idx;
+    else if (xd->mode_info_context->mbmi.ref_frame == GOLDEN_FRAME)
+      ref_fb_idx = cpi->common.gld_fb_idx;
+    else
+      ref_fb_idx = cpi->common.alt_fb_idx;
+
+    xd->pre.y_buffer = cpi->common.yv12_fb[ref_fb_idx].y_buffer + recon_yoffset;
+    xd->pre.u_buffer = cpi->common.yv12_fb[ref_fb_idx].u_buffer + recon_uvoffset;
+    xd->pre.v_buffer = cpi->common.yv12_fb[ref_fb_idx].v_buffer + recon_uvoffset;
+
+    if (xd->mode_info_context->mbmi.second_ref_frame > 0) {
+      int second_ref_fb_idx;
+
+      if (xd->mode_info_context->mbmi.second_ref_frame == LAST_FRAME)
+        second_ref_fb_idx = cpi->common.lst_fb_idx;
+      else if (xd->mode_info_context->mbmi.second_ref_frame == GOLDEN_FRAME)
+        second_ref_fb_idx = cpi->common.gld_fb_idx;
+      else
+        second_ref_fb_idx = cpi->common.alt_fb_idx;
+
+      xd->second_pre.y_buffer = cpi->common.yv12_fb[second_ref_fb_idx].y_buffer +
+                                    recon_yoffset;
+      xd->second_pre.u_buffer = cpi->common.yv12_fb[second_ref_fb_idx].u_buffer +
+                                    recon_uvoffset;
+      xd->second_pre.v_buffer = cpi->common.yv12_fb[second_ref_fb_idx].v_buffer +
+                                    recon_uvoffset;
+    }
+
+    vp9_build_inter32x32_predictors_sb(xd, xd->dst.y_buffer,
+                                       xd->dst.u_buffer, xd->dst.v_buffer,
+                                       xd->dst.y_stride, xd->dst.uv_stride);
+  }
+
+  for (n = 0; n < 4; n++) {
+    int x_idx = n & 1, y_idx = n >> 1;
+
+    xd->left_context = cm->left_context + y_idx;
+    xd->above_context = cm->above_context + mb_col + x_idx;
+    memcpy(&ta[n], xd->above_context, sizeof(ta[n]));
+    memcpy(&tl[n], xd->left_context, sizeof(tl[n]));
+    tp[n] = *t;
+    xd->mode_info_context = mi + x_idx + y_idx * cm->mode_info_stride;
+
+    vp9_subtract_mby_s_c(x->src_diff,
+                         src + x_idx * 16 + y_idx * 16 * src_y_stride,
+                         src_y_stride,
+                         dst + x_idx * 16 + y_idx * 16 * dst_y_stride,
+                         dst_y_stride);
+    vp9_subtract_mbuv_s_c(x->src_diff,
+                          usrc + x_idx * 8 + y_idx * 8 * src_uv_stride,
+                          vsrc + x_idx * 8 + y_idx * 8 * src_uv_stride,
+                          src_uv_stride,
+                          udst + x_idx * 8 + y_idx * 8 * dst_uv_stride,
+                          vdst + x_idx * 8 + y_idx * 8 * dst_uv_stride,
+                          dst_uv_stride);
+    vp9_fidct_mb(x);
+    vp9_recon_mby_s_c(&x->e_mbd,
+                      dst + x_idx * 16 + y_idx * 16 * dst_y_stride);
+    vp9_recon_mbuv_s_c(&x->e_mbd,
+                       udst + x_idx * 8 + y_idx * 8 * dst_uv_stride,
+                       vdst + x_idx * 8 + y_idx * 8 * dst_uv_stride);
+
+    if (!x->skip) {
+      vp9_tokenize_mb(cpi, &x->e_mbd, t, 0);
+      skip[n] = xd->mode_info_context->mbmi.mb_skip_coeff;
+    } else {
+      int mb_skip_context =
+        cpi->common.mb_no_coeff_skip ?
+          (x->e_mbd.mode_info_context - 1)->mbmi.mb_skip_coeff +
+            (x->e_mbd.mode_info_context - cpi->common.mode_info_stride)->mbmi.mb_skip_coeff :
+          0;
+      xd->mode_info_context->mbmi.mb_skip_coeff = skip[n] = 1;
+      if (cpi->common.mb_no_coeff_skip) {
+        // TODO(rbultje) this should be done per-sb instead of per-mb?
+        cpi->skip_true_count[mb_skip_context]++;
+        vp9_fix_contexts(xd);
+      } else {
+        vp9_stuff_mb(cpi, xd, t, 0);
+        // TODO(rbultje) this should be done per-sb instead of per-mb?
+        cpi->skip_false_count[mb_skip_context]++;
+      }
+    }
+  }
+
+  xd->mode_info_context = mi;
+  update_sb_skip_coeff_state(cpi, x, ta, tl, tp, t, skip);
+  if (cm->txfm_mode == TX_MODE_SELECT &&
+      !((cm->mb_no_coeff_skip && skip[0] && skip[1] && skip[2] && skip[3]) ||
+        (vp9_segfeature_active(xd, segment_id, SEG_LVL_EOB) &&
+         vp9_get_segdata(xd, segment_id, SEG_LVL_EOB) == 0))) {
+    cpi->txfm_count[mi->mbmi.txfm_size]++;
+  } else {
+    TX_SIZE sz = (cm->txfm_mode == TX_MODE_SELECT) ? TX_16X16 : cm->txfm_mode;
+    mi->mbmi.txfm_size = sz;
+    if (mb_col < cm->mb_cols - 1)
+      mi[1].mbmi.txfm_size = sz;
+    if (mb_row < cm->mb_rows - 1) {
+      mi[cm->mode_info_stride].mbmi.txfm_size = sz;
+      if (mb_col < cm->mb_cols - 1)
+        mi[cm->mode_info_stride + 1].mbmi.txfm_size = sz;
+    }
+  }
+}
+#endif