libvpx: Pull from upstream

source/libvpx/vp9/encoder/vp9_firstpass.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 <limits.h>
 #include <math.h>
 #include <stdio.h>
 
 #include "./vpx_scale_rtcd.h"
 
 #include "vpx_mem/vpx_mem.h"
 #include "vpx_scale/vpx_scale.h"
 #include "vpx_scale/yv12config.h"
 
 #include "vp9/common/vp9_entropymv.h"
 #include "vp9/common/vp9_quant_common.h"
 #include "vp9/common/vp9_reconinter.h"  // vp9_setup_dst_planes()
 #include "vp9/common/vp9_systemdependent.h"
-
 #include "vp9/encoder/vp9_aq_variance.h"
 #include "vp9/encoder/vp9_block.h"
 #include "vp9/encoder/vp9_encodeframe.h"
 #include "vp9/encoder/vp9_encodemb.h"
 #include "vp9/encoder/vp9_encodemv.h"
 #include "vp9/encoder/vp9_encoder.h"
 #include "vp9/encoder/vp9_extend.h"
 #include "vp9/encoder/vp9_firstpass.h"
 #include "vp9/encoder/vp9_mcomp.h"
 #include "vp9/encoder/vp9_quantize.h"
@@ skipping 13 matching lines @@
 #define FACTOR_PT_LOW 0.5
 #define FACTOR_PT_HIGH 0.9
 
 #define KF_MB_INTRA_MIN 150
 #define GF_MB_INTRA_MIN 100
 
 #define DOUBLE_DIVIDE_CHECK(x) ((x) < 0 ? (x) - 0.000001 : (x) + 0.000001)
 
 #define MIN_KF_BOOST        300
 #define MIN_GF_INTERVAL     4
-#define LONG_TERM_VBR_CORRECTION
 
 static void swap_yv12(YV12_BUFFER_CONFIG *a, YV12_BUFFER_CONFIG *b) {
   YV12_BUFFER_CONFIG temp = *a;
   *a = *b;
   *b = temp;
 }
 
 static int gfboost_qadjust(int qindex) {
   const double q = vp9_convert_qindex_to_q(qindex);
   return (int)((0.00000828 * q * q * q) +
@@ skipping 148 matching lines @@
   section->MVc        -= frame->MVc;
   section->mvc_abs     -= frame->mvc_abs;
   section->MVrv       -= frame->MVrv;
   section->MVcv       -= frame->MVcv;
   section->mv_in_out_count  -= frame->mv_in_out_count;
   section->new_mv_count -= frame->new_mv_count;
   section->count      -= frame->count;
   section->duration   -= frame->duration;
 }
 
-static void avg_stats(FIRSTPASS_STATS *section) {
-  if (section->count < 1.0)
-    return;
-
-  section->intra_error /= section->count;
-  section->coded_error /= section->count;
-  section->sr_coded_error /= section->count;
-  section->pcnt_inter  /= section->count;
-  section->pcnt_second_ref /= section->count;
-  section->pcnt_neutral /= section->count;
-  section->pcnt_motion /= section->count;
-  section->MVr        /= section->count;
-  section->mvr_abs     /= section->count;
-  section->MVc        /= section->count;
-  section->mvc_abs     /= section->count;
-  section->MVrv       /= section->count;
-  section->MVcv       /= section->count;
-  section->mv_in_out_count   /= section->count;
-  section->duration   /= section->count;
-}
 
 // Calculate a modified Error used in distributing bits between easier and
 // harder frames.
 static double calculate_modified_err(const TWO_PASS *twopass,
                                      const VP9EncoderConfig *oxcf,
                                      const FIRSTPASS_STATS *this_frame) {
   const FIRSTPASS_STATS *const stats = &twopass->total_stats;
   const double av_err = stats->coded_error / stats->count;
   const double modified_error = av_err *
       pow(this_frame->coded_error / DOUBLE_DIVIDE_CHECK(av_err),
@@ skipping 13 matching lines @@
     max_bits = rc->max_frame_bandwidth;
 
   return (int)max_bits;
 }
 
 void vp9_init_first_pass(VP9_COMP *cpi) {
   zero_stats(&cpi->twopass.total_stats);
 }
 
 void vp9_end_first_pass(VP9_COMP *cpi) {
-  if (cpi->use_svc && cpi->svc.number_temporal_layers == 1) {
+  if (is_spatial_svc(cpi)) {
     int i;
     for (i = 0; i < cpi->svc.number_spatial_layers; ++i) {
       output_stats(&cpi->svc.layer_context[i].twopass.total_stats,
                    cpi->output_pkt_list);
     }
   } else {
     output_stats(&cpi->twopass.total_stats, cpi->output_pkt_list);
   }
 }
 
@@ skipping 167 matching lines @@
   if (cpi->use_fp_mb_stats) {
     vp9_zero_array(cpi->twopass.frame_mb_stats_buf, cm->MBs);
   }
 #endif
 
   vp9_clear_system_state();
 
   set_first_pass_params(cpi);
   vp9_set_quantizer(cm, find_fp_qindex());
 
-  if (cpi->use_svc && cpi->svc.number_temporal_layers == 1) {
+  if (is_spatial_svc(cpi)) {
     MV_REFERENCE_FRAME ref_frame = LAST_FRAME;
     const YV12_BUFFER_CONFIG *scaled_ref_buf = NULL;
     twopass = &cpi->svc.layer_context[cpi->svc.spatial_layer_id].twopass;
 
     if (cpi->common.current_video_frame == 0) {
       cpi->ref_frame_flags = 0;
     } else {
       LAYER_CONTEXT *lc = &cpi->svc.layer_context[cpi->svc.spatial_layer_id];
       if (lc->current_video_frame_in_layer == 0)
         cpi->ref_frame_flags = VP9_GOLD_FLAG;
@@ skipping 66 matching lines @@
     // outside the UMV borders.
     x->mv_row_min = -((mb_row * 16) + BORDER_MV_PIXELS_B16);
     x->mv_row_max = ((cm->mb_rows - 1 - mb_row) * 16)
                     + BORDER_MV_PIXELS_B16;
 
     for (mb_col = 0; mb_col < cm->mb_cols; ++mb_col) {
       int this_error;
       const int use_dc_pred = (mb_col || mb_row) && (!mb_col || !mb_row);
       double error_weight = 1.0;
       const BLOCK_SIZE bsize = get_bsize(cm, mb_row, mb_col);
+#if CONFIG_FP_MB_STATS
+      const int mb_index = mb_row * cm->mb_cols + mb_col;
+#endif
 
       vp9_clear_system_state();
 
       xd->plane[0].dst.buf = new_yv12->y_buffer + recon_yoffset;
       xd->plane[1].dst.buf = new_yv12->u_buffer + recon_uvoffset;
       xd->plane[2].dst.buf = new_yv12->v_buffer + recon_uvoffset;
       xd->left_available = (mb_col != 0);
       xd->mi[0]->mbmi.sb_type = bsize;
       xd->mi[0]->mbmi.ref_frame[0] = INTRA_FRAME;
       set_mi_row_col(xd, &tile,
@@ skipping 26 matching lines @@
       // When the error score is very low this causes us to pick all or lots of
       // INTRA modes and throw lots of key frames.
       // This penalty adds a cost matching that of a 0,0 mv to the intra case.
       this_error += intrapenalty;
 
       // Accumulate the intra error.
       intra_error += (int64_t)this_error;
 
 #if CONFIG_FP_MB_STATS
       if (cpi->use_fp_mb_stats) {
-        // TODO(pengchong): store some related block statistics here
+        // initialization
+        cpi->twopass.frame_mb_stats_buf[mb_index] = 0;
       }
 #endif
 
       // Set up limit values for motion vectors to prevent them extending
       // outside the UMV borders.
       x->mv_col_min = -((mb_col * 16) + BORDER_MV_PIXELS_B16);
       x->mv_col_max = ((cm->mb_cols - 1 - mb_col) * 16) + BORDER_MV_PIXELS_B16;
 
       // Other than for the first frame do a motion search.
       if (cm->current_video_frame > 0) {
@@ skipping 11 matching lines @@
         // frame as the reference. Skip the further motion search on
         // reconstructed frame if this error is small.
         unscaled_last_source_buf_2d.buf =
             cpi->unscaled_last_source->y_buffer + recon_yoffset;
         unscaled_last_source_buf_2d.stride =
             cpi->unscaled_last_source->y_stride;
         raw_motion_error = get_prediction_error(bsize, &x->plane[0].src,
                                                 &unscaled_last_source_buf_2d);
 
         // TODO(pengchong): Replace the hard-coded threshold
-        if (raw_motion_error > 25 ||
-            (cpi->use_svc && cpi->svc.number_temporal_layers == 1)) {
+        if (raw_motion_error > 25 || is_spatial_svc(cpi)) {
           // Test last reference frame using the previous best mv as the
           // starting point (best reference) for the search.
           first_pass_motion_search(cpi, x, &best_ref_mv.as_mv, &mv.as_mv,
                                    &motion_error);
           if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
             vp9_clear_system_state();
             motion_error = (int)(motion_error * error_weight);
           }
 
           // If the current best reference mv is not centered on 0,0 then do a
@@ skipping 47 matching lines @@
           } else {
             sr_coded_error += motion_error;
           }
         } else {
           sr_coded_error += motion_error;
         }
 
         // Start by assuming that intra mode is best.
         best_ref_mv.as_int = 0;
 
+#if CONFIG_FP_MB_STATS
+        if (cpi->use_fp_mb_stats) {
+          // intra predication statistics
+          cpi->twopass.frame_mb_stats_buf[mb_index] = 0;
+          cpi->twopass.frame_mb_stats_buf[mb_index] |= FPMB_DCINTRA_MASK;
+          cpi->twopass.frame_mb_stats_buf[mb_index] |= FPMB_MOTION_ZERO_MASK;
+          if (this_error > FPMB_ERROR_LARGE_TH) {
+            cpi->twopass.frame_mb_stats_buf[mb_index] |= FPMB_ERROR_LARGE_MASK;
+          } else if (this_error < FPMB_ERROR_SMALL_TH) {
+            cpi->twopass.frame_mb_stats_buf[mb_index] |= FPMB_ERROR_SMALL_MASK;
+          }
+        }
+#endif
+
         if (motion_error <= this_error) {
           // Keep a count of cases where the inter and intra were very close
           // and very low. This helps with scene cut detection for example in
           // cropped clips with black bars at the sides or top and bottom.
           if (((this_error - intrapenalty) * 9 <= motion_error * 10) &&
               this_error < 2 * intrapenalty)
             ++neutral_count;
 
           mv.as_mv.row *= 8;
           mv.as_mv.col *= 8;
@@ skipping 10 matching lines @@
           sum_mvc += mv.as_mv.col;
           sum_mvc_abs += abs(mv.as_mv.col);
           sum_mvrs += mv.as_mv.row * mv.as_mv.row;
           sum_mvcs += mv.as_mv.col * mv.as_mv.col;
           ++intercount;
 
           best_ref_mv.as_int = mv.as_int;
 
 #if CONFIG_FP_MB_STATS
           if (cpi->use_fp_mb_stats) {
-            // TODO(pengchong): save some related block statistics here
+            // inter predication statistics
+            cpi->twopass.frame_mb_stats_buf[mb_index] = 0;
+            cpi->twopass.frame_mb_stats_buf[mb_index] &= ~FPMB_DCINTRA_MASK;
+            cpi->twopass.frame_mb_stats_buf[mb_index] |= FPMB_MOTION_ZERO_MASK;
+            if (this_error > FPMB_ERROR_LARGE_TH) {
+              cpi->twopass.frame_mb_stats_buf[mb_index] |=
+                  FPMB_ERROR_LARGE_MASK;
+            } else if (this_error < FPMB_ERROR_SMALL_TH) {
+              cpi->twopass.frame_mb_stats_buf[mb_index] |=
+                  FPMB_ERROR_SMALL_MASK;
+            }
           }
 #endif
 
           if (mv.as_int) {
             ++mvcount;
 
+#if CONFIG_FP_MB_STATS
+            if (cpi->use_fp_mb_stats) {
+              cpi->twopass.frame_mb_stats_buf[mb_index] &=
+                  ~FPMB_MOTION_ZERO_MASK;
+              // check estimated motion direction
+              if (mv.as_mv.col > 0 && mv.as_mv.col >= abs(mv.as_mv.row)) {
+                // right direction
+                cpi->twopass.frame_mb_stats_buf[mb_index] |=
+                    FPMB_MOTION_RIGHT_MASK;
+              } else if (mv.as_mv.row < 0 &&
+                         abs(mv.as_mv.row) >= abs(mv.as_mv.col)) {
+                // up direction
+                cpi->twopass.frame_mb_stats_buf[mb_index] |=
+                    FPMB_MOTION_UP_MASK;
+              } else if (mv.as_mv.col < 0 &&
+                         abs(mv.as_mv.col) >= abs(mv.as_mv.row)) {
+                // left direction
+                cpi->twopass.frame_mb_stats_buf[mb_index] |=
+                    FPMB_MOTION_LEFT_MASK;
+              } else {
+                // down direction
+                cpi->twopass.frame_mb_stats_buf[mb_index] |=
+                    FPMB_MOTION_DOWN_MASK;
+              }
+            }
+#endif
+
             // Non-zero vector, was it different from the last non zero vector?
             if (mv.as_int != lastmv_as_int)
               ++new_mv_count;
             lastmv_as_int = mv.as_int;
 
             // Does the row vector point inwards or outwards?
             if (mb_row < cm->mb_rows / 2) {
               if (mv.as_mv.row > 0)
                 --sum_in_vectors;
               else if (mv.as_mv.row < 0)
@@ skipping 106 matching lines @@
     if (gld_yv12 != NULL) {
       vp8_yv12_copy_frame(lst_yv12, gld_yv12);
     }
     twopass->sr_update_lag = 1;
   } else {
     ++twopass->sr_update_lag;
   }
 
   vp9_extend_frame_borders(new_yv12);
 
-  if (cpi->use_svc && cpi->svc.number_temporal_layers == 1) {
+  if (is_spatial_svc(cpi)) {
     vp9_update_reference_frames(cpi);
   } else {
     // Swap frame pointers so last frame refers to the frame we just compressed.
     swap_yv12(lst_yv12, new_yv12);
   }
 
   // Special case for the first frame. Copy into the GF buffer as a second
   // reference.
   if (cm->current_video_frame == 0 && gld_yv12 != NULL) {
     vp8_yv12_copy_frame(lst_yv12, gld_yv12);
@@ skipping 45 matching lines @@
   const VP9EncoderConfig *const oxcf = &cpi->oxcf;
 
   if (section_target_bandwidth <= 0) {
     return rc->worst_quality;  // Highest value allowed
   } else {
     const int num_mbs = cpi->common.MBs;
     const double section_err = stats->coded_error / stats->count;
     const double err_per_mb = section_err / num_mbs;
     const double speed_term = 1.0 + 0.04 * oxcf->speed;
     const int target_norm_bits_per_mb = ((uint64_t)section_target_bandwidth <<
-                                            BPER_MB_NORMBITS) / num_mbs;
+                                         BPER_MB_NORMBITS) / num_mbs;
     int q;
     int is_svc_upper_layer = 0;
-    if (cpi->use_svc && cpi->svc.number_temporal_layers == 1 &&
-        cpi->svc.spatial_layer_id > 0) {
+    if (is_spatial_svc(cpi) && cpi->svc.spatial_layer_id > 0)
       is_svc_upper_layer = 1;
-    }
 
     // Try and pick a max Q that will be high enough to encode the
     // content at the given rate.
     for (q = rc->best_quality; q < rc->worst_quality; ++q) {
       const double factor =
           calc_correction_factor(err_per_mb, ERR_DIVISOR,
                                  is_svc_upper_layer ? SVC_FACTOR_PT_LOW :
                                  FACTOR_PT_LOW, FACTOR_PT_HIGH, q);
       const int bits_per_mb = vp9_rc_bits_per_mb(INTER_FRAME, q,
                                                  factor * speed_term);
@@ skipping 93 matching lines @@
   // and the GF buffer (which contains an older frame).
   const double mb_sr_err_diff = (next_frame->sr_coded_error -
                                      next_frame->coded_error) / cm->MBs;
   const double second_ref_decay = mb_sr_err_diff <= 512.0
       ? fclamp(pow(1.0 - (mb_sr_err_diff / 512.0), 0.5), 0.85, 1.0)
       : 0.85;
 
   return MIN(second_ref_decay, next_frame->pcnt_inter);
 }
 
+// This function gives an estimate of how badly we believe the prediction
+// quality is decaying from frame to frame.
+static double get_zero_motion_factor(const VP9_COMMON *cm,
+                                     const FIRSTPASS_STATS *frame) {
+  const double sr_ratio = frame->coded_error /
+                          DOUBLE_DIVIDE_CHECK(frame->sr_coded_error);
+  const double zero_motion_pct = frame->pcnt_inter -
+                                 frame->pcnt_motion;
+
+  return MIN(sr_ratio, zero_motion_pct);
+}
+
+
 // Function to test for a condition where a complex transition is followed
 // by a static section. For example in slide shows where there is a fade
 // between slides. This is to help with more optimal kf and gf positioning.
 static int detect_transition_to_still(TWO_PASS *twopass,
                                       int frame_interval, int still_interval,
                                       double loop_decay_rate,
                                       double last_decay_rate) {
   int trans_to_still = 0;
 
   // Break clause to detect very still sections after motion
@@ skipping 503 matching lines @@
                                   &abs_mv_in_out_accumulator,
                                   &mv_ratio_accumulator);
 
     // Accumulate the effect of prediction quality decay.
     if (!flash_detected) {
       last_loop_decay_rate = loop_decay_rate;
       loop_decay_rate = get_prediction_decay_rate(&cpi->common, &next_frame);
       decay_accumulator = decay_accumulator * loop_decay_rate;
 
       // Monitor for static sections.
-      if ((next_frame.pcnt_inter - next_frame.pcnt_motion) <
-          zero_motion_accumulator) {
-        zero_motion_accumulator = next_frame.pcnt_inter -
-                                      next_frame.pcnt_motion;
-      }
+      zero_motion_accumulator =
+        MIN(zero_motion_accumulator,
+            get_zero_motion_factor(&cpi->common, &next_frame));
 
       // Break clause to detect very still sections after motion. For example,
       // a static image after a fade or other transition.
       if (detect_transition_to_still(twopass, i, 5, loop_decay_rate,
                                      last_loop_decay_rate)) {
         allow_alt_ref = 0;
         break;
       }
     }
 
@@ skipping 349 matching lines @@
 
   // Scan through the kf group collating various stats used to deteermine
   // how many bits to spend on it.
   decay_accumulator = 1.0;
   boost_score = 0.0;
   for (i = 0; i < rc->frames_to_key; ++i) {
     if (EOF == input_stats(twopass, &next_frame))
       break;
 
     // Monitor for static sections.
-    if ((next_frame.pcnt_inter - next_frame.pcnt_motion) <
-            zero_motion_accumulator) {
-      zero_motion_accumulator = (next_frame.pcnt_inter -
-                                     next_frame.pcnt_motion);
-    }
+    zero_motion_accumulator =
+      MIN(zero_motion_accumulator,
+          get_zero_motion_factor(&cpi->common, &next_frame));
 
     // For the first few frames collect data to decide kf boost.
     if (i <= (rc->max_gf_interval * 2)) {
       double r;
       if (next_frame.intra_error > twopass->kf_intra_err_min)
         r = (IIKFACTOR2 * next_frame.intra_error /
              DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
       else
         r = (IIKFACTOR2 * twopass->kf_intra_err_min /
              DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
@@ skipping 94 matching lines @@
       cpi->refresh_alt_ref_frame = 0;
       cpi->rc.is_src_frame_alt_ref = 1;
       break;
     case ARF_UPDATE:
       cpi->refresh_last_frame = 0;
       cpi->refresh_golden_frame = 0;
       cpi->refresh_alt_ref_frame = 1;
       break;
     default:
       assert(0);
+      break;
   }
-  if (cpi->use_svc && cpi->svc.number_temporal_layers == 1) {
-    cpi->refresh_golden_frame = 0;
+  if (is_spatial_svc(cpi)) {
+    if (cpi->svc.layer_context[cpi->svc.spatial_layer_id].gold_ref_idx < 0)
+      cpi->refresh_golden_frame = 0;
     if (cpi->alt_ref_source == NULL)
       cpi->refresh_alt_ref_frame = 0;
   }
 }
 
 
 void vp9_rc_get_second_pass_params(VP9_COMP *cpi) {
   VP9_COMMON *const cm = &cpi->common;
   RATE_CONTROL *const rc = &cpi->rc;
   TWO_PASS *const twopass = &cpi->twopass;
   int frames_left;
   FIRSTPASS_STATS this_frame;
   FIRSTPASS_STATS this_frame_copy;
 
   int target_rate;
   LAYER_CONTEXT *lc = NULL;
-  const int is_spatial_svc = (cpi->use_svc &&
-                              cpi->svc.number_temporal_layers == 1);
-  if (is_spatial_svc) {
+
+  if (is_spatial_svc(cpi)) {
     lc = &cpi->svc.layer_context[cpi->svc.spatial_layer_id];
     frames_left = (int)(twopass->total_stats.count -
                   lc->current_video_frame_in_layer);
   } else {
     frames_left = (int)(twopass->total_stats.count -
                   cm->current_video_frame);
   }
 
   if (!twopass->stats_in)
     return;
 
   // If this is an arf frame then we dont want to read the stats file or
   // advance the input pointer as we already have what we need.
   if (twopass->gf_group.update_type[twopass->gf_group.index] == ARF_UPDATE) {
     int target_rate;
     configure_buffer_updates(cpi);
     target_rate = twopass->gf_group.bit_allocation[twopass->gf_group.index];
     target_rate = vp9_rc_clamp_pframe_target_size(cpi, target_rate);
     rc->base_frame_target = target_rate;
-#ifdef LONG_TERM_VBR_CORRECTION
+
     // Correction to rate target based on prior over or under shoot.
     if (cpi->oxcf.rc_mode == VPX_VBR)
       vbr_rate_correction(&target_rate, rc->vbr_bits_off_target);
-#endif
+
     vp9_rc_set_frame_target(cpi, target_rate);
     cm->frame_type = INTER_FRAME;
 
-    if (is_spatial_svc) {
+    if (is_spatial_svc(cpi)) {
       if (cpi->svc.spatial_layer_id == 0) {
         lc->is_key_frame = 0;
       } else {
         lc->is_key_frame = cpi->svc.layer_context[0].is_key_frame;
 
         if (lc->is_key_frame)
           cpi->ref_frame_flags &= (~VP9_LAST_FLAG);
       }
     }
 
     return;
   }
 
   vp9_clear_system_state();
 
-  if (is_spatial_svc && twopass->kf_intra_err_min == 0) {
+  if (is_spatial_svc(cpi) && twopass->kf_intra_err_min == 0) {
     twopass->kf_intra_err_min = KF_MB_INTRA_MIN * cpi->common.MBs;
     twopass->gf_intra_err_min = GF_MB_INTRA_MIN * cpi->common.MBs;
   }
 
   if (cpi->oxcf.rc_mode == VPX_Q) {
     twopass->active_worst_quality = cpi->oxcf.cq_level;
   } else if (cm->current_video_frame == 0 ||
-             (is_spatial_svc && lc->current_video_frame_in_layer == 0)) {
+             (is_spatial_svc(cpi) &&
+              lc->current_video_frame_in_layer == 0)) {
     // Special case code for first frame.
     const int section_target_bandwidth = (int)(twopass->bits_left /
                                                frames_left);
     const int tmp_q = get_twopass_worst_quality(cpi, &twopass->total_left_stats,
                                                 section_target_bandwidth);
     twopass->active_worst_quality = tmp_q;
     rc->ni_av_qi = tmp_q;
     rc->avg_q = vp9_convert_qindex_to_q(tmp_q);
   }
   vp9_zero(this_frame);
   if (EOF == input_stats(twopass, &this_frame))
     return;
 
   // Local copy of the current frame's first pass stats.
   this_frame_copy = this_frame;
 
   // Keyframe and section processing.
   if (rc->frames_to_key == 0 ||
       (cpi->frame_flags & FRAMEFLAGS_KEY)) {
     // Define next KF group and assign bits to it.
     find_next_key_frame(cpi, &this_frame_copy);
   } else {
     cm->frame_type = INTER_FRAME;
   }
 
-  if (is_spatial_svc) {
+  if (is_spatial_svc(cpi)) {
     if (cpi->svc.spatial_layer_id == 0) {
       lc->is_key_frame = (cm->frame_type == KEY_FRAME);
+      if (lc->is_key_frame)
+        cpi->ref_frame_flags &=
+            (~VP9_LAST_FLAG & ~VP9_GOLD_FLAG & ~VP9_ALT_FLAG);
     } else {
       cm->frame_type = INTER_FRAME;
       lc->is_key_frame = cpi->svc.layer_context[0].is_key_frame;
 
       if (lc->is_key_frame) {
         cpi->ref_frame_flags &= (~VP9_LAST_FLAG);
       }
     }
   }
 
   // Define a new GF/ARF group. (Should always enter here for key frames).
   if (rc->frames_till_gf_update_due == 0) {
     define_gf_group(cpi, &this_frame_copy);
 
     if (twopass->gf_zeromotion_pct > 995) {
       // As long as max_thresh for encode breakout is small enough, it is ok
       // to enable it for show frame, i.e. set allow_encode_breakout to
       // ENCODE_BREAKOUT_LIMITED.
       if (!cm->show_frame)
         cpi->allow_encode_breakout = ENCODE_BREAKOUT_DISABLED;
       else
         cpi->allow_encode_breakout = ENCODE_BREAKOUT_LIMITED;
     }
 
     rc->frames_till_gf_update_due = rc->baseline_gf_interval;
-    if (!is_spatial_svc)
+    if (!is_spatial_svc(cpi))
       cpi->refresh_golden_frame = 1;
   }
 
   configure_buffer_updates(cpi);
 
   target_rate = twopass->gf_group.bit_allocation[twopass->gf_group.index];
   if (cpi->common.frame_type == KEY_FRAME)
     target_rate = vp9_rc_clamp_iframe_target_size(cpi, target_rate);
   else
     target_rate = vp9_rc_clamp_pframe_target_size(cpi, target_rate);
 
   rc->base_frame_target = target_rate;
-#ifdef LONG_TERM_VBR_CORRECTION
+
   // Correction to rate target based on prior over or under shoot.
   if (cpi->oxcf.rc_mode == VPX_VBR)
     vbr_rate_correction(&target_rate, rc->vbr_bits_off_target);
-#endif
+
   vp9_rc_set_frame_target(cpi, target_rate);
 
   // Update the total stats remaining structure.
   subtract_stats(&twopass->total_left_stats, &this_frame);
 }
 
 void vp9_twopass_postencode_update(VP9_COMP *cpi) {
   TWO_PASS *const twopass = &cpi->twopass;
   RATE_CONTROL *const rc = &cpi->rc;
-#ifdef LONG_TERM_VBR_CORRECTION
-  // In this experimental mode, the VBR correction is done exclusively through
-  // rc->vbr_bits_off_target. Based on the sign of this value, a limited %
-  // adjustment is made to the target rate of subsequent frames, to try and
-  // push it back towards 0. This mode is less likely to suffer from
-  // extreme behaviour at the end of a clip or group of frames.
+
+  // VBR correction is done through rc->vbr_bits_off_target. Based on the
+  // sign of this value, a limited % adjustment is made to the target rate
+  // of subsequent frames, to try and push it back towards 0. This method
+  // is designed to prevent extreme behaviour at the end of a clip
+  // or group of frames.
   const int bits_used = rc->base_frame_target;
   rc->vbr_bits_off_target += rc->base_frame_target - rc->projected_frame_size;
-#else
-  // In this mode, VBR correction is acheived by altering bits_left,
-  // kf_group_bits & gf_group_bits to reflect any deviation from the target
-  // rate in this frame. This alters the allocation of bits to the
-  // remaning frames in the group / clip.
-  //
-  // This method can give rise to unstable behaviour near the end of a clip
-  // or kf/gf group of frames where any accumulated error is corrected over an
-  // ever decreasing number of frames. Hence we change the balance of target
-  // vs. actual bitrate gradually as we progress towards the end of the
-  // sequence in order to mitigate this effect.
-  const double progress =
-      (double)(twopass->stats_in - twopass->stats_in_start) /
-              (twopass->stats_in_end - twopass->stats_in_start);
-  const int bits_used = (int)(progress * rc->this_frame_target +
-                             (1.0 - progress) * rc->projected_frame_size);
-#endif
 
   twopass->bits_left = MAX(twopass->bits_left - bits_used, 0);
 
-#ifdef LONG_TERM_VBR_CORRECTION
   if (cpi->common.frame_type != KEY_FRAME &&
       !vp9_is_upper_layer_key_frame(cpi)) {
-#else
-  if (cpi->common.frame_type == KEY_FRAME ||
-      vp9_is_upper_layer_key_frame(cpi)) {
-    // For key frames kf_group_bits already had the target bits subtracted out.
-    // So now update to the correct value based on the actual bits used.
-    twopass->kf_group_bits += rc->this_frame_target - bits_used;
-  } else {
-#endif
     twopass->kf_group_bits -= bits_used;
   }
   twopass->kf_group_bits = MAX(twopass->kf_group_bits, 0);
 
   // Increment the gf group index ready for the next frame.
   ++twopass->gf_group.index;
 }