Merge "Move frame re-sizing into the recode loop"

3 files changed, 327 insertions, 259 deletions

diff --git a/vp9/encoder/vp9_encoder.c b/vp9/encoder/vp9_encoder.c
index 0ea129b90..ded590b96 100644
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -2409,30 +2409,37 @@ void vp9_scale_references(VP9_COMP *cpi) {
   const VP9_REFFRAME ref_mask[3] = {VP9_LAST_FLAG, VP9_GOLD_FLAG, VP9_ALT_FLAG};
 
   for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
-    const int idx = cm->ref_frame_map[get_ref_frame_idx(cpi, ref_frame)];
-    const YV12_BUFFER_CONFIG *const ref = &cm->frame_bufs[idx].buf;
-
     // Need to convert from VP9_REFFRAME to index into ref_mask (subtract 1).
-    if ((cpi->ref_frame_flags & ref_mask[ref_frame - 1]) &&
-        (ref->y_crop_width != cm->width || ref->y_crop_height != cm->height)) {
-      const int new_fb = get_free_fb(cm);
-      vp9_realloc_frame_buffer(&cm->frame_bufs[new_fb].buf,
-                               cm->width, cm->height,
-                               cm->subsampling_x, cm->subsampling_y,
-#if CONFIG_VP9_HIGHBITDEPTH
-                               cm->use_highbitdepth,
-#endif  // CONFIG_VP9_HIGHBITDEPTH
-                               VP9_ENC_BORDER_IN_PIXELS, NULL, NULL, NULL);
+    if (cpi->ref_frame_flags & ref_mask[ref_frame - 1]) {
+      const int idx = cm->ref_frame_map[get_ref_frame_idx(cpi, ref_frame)];
+      const YV12_BUFFER_CONFIG *const ref = &cm->frame_bufs[idx].buf;
+
 #if CONFIG_VP9_HIGHBITDEPTH
-      scale_and_extend_frame(ref, &cm->frame_bufs[new_fb].buf,
-                             (int)cm->bit_depth);
+      if (ref->y_crop_width != cm->width || ref->y_crop_height != cm->height) {
+        const int new_fb = get_free_fb(cm);
+        vp9_realloc_frame_buffer(&cm->frame_bufs[new_fb].buf,
+                                 cm->width, cm->height,
+                                 cm->subsampling_x, cm->subsampling_y,
+                                 cm->use_highbitdepth,
+                                 VP9_ENC_BORDER_IN_PIXELS, NULL, NULL, NULL);
+        scale_and_extend_frame(ref, &cm->frame_bufs[new_fb].buf,
+                               (int)cm->bit_depth);
 #else
-      scale_and_extend_frame(ref, &cm->frame_bufs[new_fb].buf);
+      if (ref->y_crop_width != cm->width || ref->y_crop_height != cm->height) {
+        const int new_fb = get_free_fb(cm);
+        vp9_realloc_frame_buffer(&cm->frame_bufs[new_fb].buf,
+                                 cm->width, cm->height,
+                                 cm->subsampling_x, cm->subsampling_y,
+                                 VP9_ENC_BORDER_IN_PIXELS, NULL, NULL, NULL);
+        scale_and_extend_frame(ref, &cm->frame_bufs[new_fb].buf);
 #endif  // CONFIG_VP9_HIGHBITDEPTH
-      cpi->scaled_ref_idx[ref_frame - 1] = new_fb;
+        cpi->scaled_ref_idx[ref_frame - 1] = new_fb;
+      } else {
+        cpi->scaled_ref_idx[ref_frame - 1] = idx;
+        ++cm->frame_bufs[idx].ref_count;
+      }
     } else {
-      cpi->scaled_ref_idx[ref_frame - 1] = idx;
-      cm->frame_bufs[idx].ref_count++;
+      cpi->scaled_ref_idx[ref_frame - 1] = INVALID_REF_BUFFER_IDX;
     }
   }
 }
@@ -2440,9 +2447,13 @@ void vp9_scale_references(VP9_COMP *cpi) {
 static void release_scaled_references(VP9_COMP *cpi) {
   VP9_COMMON *cm = &cpi->common;
   int i;
-
-  for (i = 0; i < 3; i++)
-    cm->frame_bufs[cpi->scaled_ref_idx[i]].ref_count--;
+  for (i = 0; i < MAX_REF_FRAMES; ++i) {
+    const int idx = cpi->scaled_ref_idx[i];
+    RefCntBuffer *const buf =
+        idx != INVALID_REF_BUFFER_IDX ? &cm->frame_bufs[idx] : NULL;
+    if (buf != NULL)
+      --buf->ref_count;
+  }
 }
 
 static void full_to_model_count(unsigned int *model_count,
@@ -2527,10 +2538,181 @@ static void output_frame_level_debug_stats(VP9_COMP *cpi) {
 }
 #endif
 
-static void encode_without_recode_loop(VP9_COMP *cpi,
-                                       int q) {
+static void set_mv_search_params(VP9_COMP *cpi) {
+  const VP9_COMMON *const cm = &cpi->common;
+  const unsigned int max_mv_def = MIN(cm->width, cm->height);
+
+  // Default based on max resolution.
+  cpi->mv_step_param = vp9_init_search_range(max_mv_def);
+
+  if (cpi->sf.mv.auto_mv_step_size) {
+    if (frame_is_intra_only(cm)) {
+      // Initialize max_mv_magnitude for use in the first INTER frame
+      // after a key/intra-only frame.
+      cpi->max_mv_magnitude = max_mv_def;
+    } else {
+      if (cm->show_frame) {
+        // Allow mv_steps to correspond to twice the max mv magnitude found
+        // in the previous frame, capped by the default max_mv_magnitude based
+        // on resolution.
+        cpi->mv_step_param =
+            vp9_init_search_range(MIN(max_mv_def, 2 * cpi->max_mv_magnitude));
+      }
+      cpi->max_mv_magnitude = 0;
+    }
+  }
+}
+
+static void set_size_dependent_vars(VP9_COMP *cpi, int *q,
+                                    int *bottom_index, int *top_index) {
+  VP9_COMMON *const cm = &cpi->common;
+  const VP9EncoderConfig *const oxcf = &cpi->oxcf;
+
+  // Setup variables that depend on the dimensions of the frame.
+  set_mv_search_params(cpi);
+
+  // Configure experimental use of segmentation for enhanced coding of
+  // static regions if indicated.
+  // Only allowed in the second pass of a two pass encode, as it requires
+  // lagged coding, and if the relevant speed feature flag is set.
+  if (oxcf->pass == 2 && cpi->sf.static_segmentation)
+    configure_static_seg_features(cpi);
+
+#if CONFIG_VP9_POSTPROC
+  if (oxcf->noise_sensitivity > 0) {
+    int l = 0;
+    switch (oxcf->noise_sensitivity) {
+      case 1:
+        l = 20;
+        break;
+      case 2:
+        l = 40;
+        break;
+      case 3:
+        l = 60;
+        break;
+      case 4:
+      case 5:
+        l = 100;
+        break;
+      case 6:
+        l = 150;
+        break;
+    }
+    vp9_denoise(cpi->Source, cpi->Source, l);
+  }
+#endif  // CONFIG_VP9_POSTPROC
+
+  vp9_set_speed_features(cpi);
+
+  vp9_set_rd_speed_thresholds(cpi);
+  vp9_set_rd_speed_thresholds_sub8x8(cpi);
+
+  // Decide q and q bounds.
+  *q = vp9_rc_pick_q_and_bounds(cpi, bottom_index, top_index);
+
+  if (!frame_is_intra_only(cm)) {
+    cm->interp_filter = cpi->sf.default_interp_filter;
+    vp9_set_high_precision_mv(cpi, (*q) < HIGH_PRECISION_MV_QTHRESH);
+  }
+}
+
+static void init_motion_estimation(VP9_COMP *cpi) {
+  int y_stride = cpi->scaled_source.y_stride;
+
+  if (cpi->sf.mv.search_method == NSTEP) {
+    vp9_init3smotion_compensation(&cpi->ss_cfg, y_stride);
+  } else if (cpi->sf.mv.search_method == DIAMOND) {
+    vp9_init_dsmotion_compensation(&cpi->ss_cfg, y_stride);
+  }
+}
+
+extern void vbr_rate_correction(VP9_COMP *cpi,
+                                int * this_frame_target,
+                                const int64_t vbr_bits_off_target);
+
+void set_frame_size(VP9_COMP *cpi) {
+  int ref_frame;
+  VP9_COMMON *const cm = &cpi->common;
+  const RATE_CONTROL *const rc = &cpi->rc;
+  const VP9EncoderConfig *const oxcf = &cpi->oxcf;
+  MACROBLOCKD *const xd = &cpi->mb.e_mbd;
+
+  if ((oxcf->pass == 2) &&
+      (!cpi->use_svc ||
+          (is_two_pass_svc(cpi) &&
+              cpi->svc.encode_empty_frame_state != ENCODING))) {
+    int target_rate = rc->base_frame_target;
+    if (oxcf->rc_mode == VPX_VBR)
+      vbr_rate_correction(cpi, &target_rate, rc->vbr_bits_off_target);
+    vp9_rc_set_frame_target(cpi, target_rate);
+  }
+
+  if (oxcf->pass == 2 &&
+      cm->current_video_frame == 0 &&
+      oxcf->allow_spatial_resampling &&
+      oxcf->rc_mode == VPX_VBR) {
+    // Internal scaling is triggered on the first frame.
+    vp9_set_size_literal(cpi, oxcf->scaled_frame_width,
+                         oxcf->scaled_frame_height);
+  }
+
+  // Reset the frame pointers to the current frame size.
+  vp9_realloc_frame_buffer(get_frame_new_buffer(cm),
+                           cm->width, cm->height,
+                           cm->subsampling_x, cm->subsampling_y,
+#if CONFIG_VP9_HIGHBITDEPTH
+                           cm->use_highbitdepth,
+#endif
+                           VP9_ENC_BORDER_IN_PIXELS, NULL, NULL, NULL);
+
+  alloc_util_frame_buffers(cpi);
+  init_motion_estimation(cpi);
+
+  for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
+    const int idx = cm->ref_frame_map[get_ref_frame_idx(cpi, ref_frame)];
+    YV12_BUFFER_CONFIG *const buf = &cm->frame_bufs[idx].buf;
+    RefBuffer *const ref_buf = &cm->frame_refs[ref_frame - 1];
+    ref_buf->buf = buf;
+    ref_buf->idx = idx;
+#if CONFIG_VP9_HIGHBITDEPTH
+    vp9_setup_scale_factors_for_frame(&ref_buf->sf,
+                                      buf->y_crop_width, buf->y_crop_height,
+                                      cm->width, cm->height,
+                                      (buf->flags & YV12_FLAG_HIGHBITDEPTH) ?
+                                          1 : 0);
+#else
+    vp9_setup_scale_factors_for_frame(&ref_buf->sf,
+                                      buf->y_crop_width, buf->y_crop_height,
+                                      cm->width, cm->height);
+#endif  // CONFIG_VP9_HIGHBITDEPTH
+    if (vp9_is_scaled(&ref_buf->sf))
+      vp9_extend_frame_borders(buf);
+  }
+
+  set_ref_ptrs(cm, xd, LAST_FRAME, LAST_FRAME);
+}
+
+static void encode_without_recode_loop(VP9_COMP *cpi) {
+  int q;
+  int bottom_index, top_index;  // Dummy.
   VP9_COMMON *const cm = &cpi->common;
+
   vp9_clear_system_state();
+
+  set_frame_size(cpi);
+
+  cpi->Source = vp9_scale_if_required(cm, cpi->un_scaled_source,
+                                      &cpi->scaled_source);
+
+  if (cpi->unscaled_last_source != NULL)
+    cpi->Last_Source = vp9_scale_if_required(cm, cpi->unscaled_last_source,
+                                             &cpi->scaled_last_source);
+
+  vp9_scale_references(cpi);
+
+  set_size_dependent_vars(cpi, &q, &bottom_index, &top_index);
+
   vp9_set_quantizer(cm, q);
   setup_frame(cpi);
   // Variance adaptive and in frame q adjustment experiments are mutually
@@ -2553,28 +2735,45 @@ static void encode_without_recode_loop(VP9_COMP *cpi,
 
 static void encode_with_recode_loop(VP9_COMP *cpi,
                                     size_t *size,
-                                    uint8_t *dest,
-                                    int q,
-                                    int bottom_index,
-                                    int top_index) {
+                                    uint8_t *dest) {
   VP9_COMMON *const cm = &cpi->common;
   RATE_CONTROL *const rc = &cpi->rc;
+  int q;
+  int q_low, q_high;
+  int bottom_index, top_index;
   int loop_count = 0;
   int loop = 0;
   int overshoot_seen = 0;
   int undershoot_seen = 0;
-  int q_low = bottom_index, q_high = top_index;
   int frame_over_shoot_limit;
   int frame_under_shoot_limit;
 
-  // Decide frame size bounds
-  vp9_rc_compute_frame_size_bounds(cpi, rc->this_frame_target,
-                                   &frame_under_shoot_limit,
-                                   &frame_over_shoot_limit);
-
   do {
     vp9_clear_system_state();
 
+    if (loop_count == 0) {
+      set_frame_size(cpi);
+
+      // Decide frame size bounds
+      vp9_rc_compute_frame_size_bounds(cpi, rc->this_frame_target,
+                                       &frame_under_shoot_limit,
+                                       &frame_over_shoot_limit);
+
+      cpi->Source = vp9_scale_if_required(cm, cpi->un_scaled_source,
+                                        &cpi->scaled_source);
+
+      if (cpi->unscaled_last_source != NULL)
+        cpi->Last_Source = vp9_scale_if_required(cm, cpi->unscaled_last_source,
+                                                 &cpi->scaled_last_source);
+
+      vp9_scale_references(cpi);
+
+      set_size_dependent_vars(cpi, &q, &bottom_index, &top_index);
+
+      q_low = bottom_index;
+      q_high = top_index;
+    }
+
     vp9_set_quantizer(cm, q);
 
     if (loop_count == 0)
@@ -2816,25 +3015,6 @@ YV12_BUFFER_CONFIG *vp9_scale_if_required(VP9_COMMON *cm,
   }
 }
 
-static int is_skippable_frame(const VP9_COMP *cpi) {
-  // If the current frame does not have non-zero motion vector detected in the
-  // first  pass, and so do its previous and forward frames, then this frame
-  // can be skipped for partition check, and the partition size is assigned
-  // according to the variance
-  const SVC *const svc = &cpi->svc;
-  const TWO_PASS *const twopass = is_two_pass_svc(cpi) ?
-      &svc->layer_context[svc->spatial_layer_id].twopass : &cpi->twopass;
-
-  return (!frame_is_intra_only(&cpi->common) &&
-    twopass->stats_in - 2 > twopass->stats_in_start &&
-    twopass->stats_in < twopass->stats_in_end &&
-    (twopass->stats_in - 1)->pcnt_inter - (twopass->stats_in - 1)->pcnt_motion
-    == 1 &&
-    (twopass->stats_in - 2)->pcnt_inter - (twopass->stats_in - 2)->pcnt_motion
-    == 1 &&
-    twopass->stats_in->pcnt_inter - twopass->stats_in->pcnt_motion == 1);
-}
-
 static void set_arf_sign_bias(VP9_COMP *cpi) {
   VP9_COMMON *const cm = &cpi->common;
   int arf_sign_bias;
@@ -2851,31 +3031,6 @@ static void set_arf_sign_bias(VP9_COMP *cpi) {
   cm->ref_frame_sign_bias[ALTREF_FRAME] = arf_sign_bias;
 }
 
-static void set_mv_search_params(VP9_COMP *cpi) {
-  const VP9_COMMON *const cm = &cpi->common;
-  const unsigned int max_mv_def = MIN(cm->width, cm->height);
-
-  // Default based on max resolution.
-  cpi->mv_step_param = vp9_init_search_range(max_mv_def);
-
-  if (cpi->sf.mv.auto_mv_step_size) {
-    if (frame_is_intra_only(cm)) {
-      // Initialize max_mv_magnitude for use in the first INTER frame
-      // after a key/intra-only frame.
-      cpi->max_mv_magnitude = max_mv_def;
-    } else {
-      if (cm->show_frame)
-        // Allow mv_steps to correspond to twice the max mv magnitude found
-        // in the previous frame, capped by the default max_mv_magnitude based
-        // on resolution.
-        cpi->mv_step_param =
-            vp9_init_search_range(MIN(max_mv_def, 2 * cpi->max_mv_magnitude));
-      cpi->max_mv_magnitude = 0;
-    }
-  }
-}
-
-
 int setup_interp_filter_search_mask(VP9_COMP *cpi) {
   INTERP_FILTER ifilter;
   int ref_total[MAX_REF_FRAMES] = {0};
@@ -2910,21 +3065,9 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi,
   const VP9EncoderConfig *const oxcf = &cpi->oxcf;
   struct segmentation *const seg = &cm->seg;
   TX_SIZE t;
-  int q;
-  int top_index;
-  int bottom_index;
 
   set_ext_overrides(cpi);
 
-  cpi->Source = vp9_scale_if_required(cm, cpi->un_scaled_source,
-                                      &cpi->scaled_source);
-
-  if (cpi->unscaled_last_source != NULL)
-    cpi->Last_Source = vp9_scale_if_required(cm, cpi->unscaled_last_source,
-                                             &cpi->scaled_last_source);
-
-  vp9_scale_references(cpi);
-
   vp9_clear_system_state();
 
   // Enable or disable mode based tweaking of the zbin.
@@ -2939,14 +3082,11 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi,
   // Set default state for segment based loop filter update flags.
   cm->lf.mode_ref_delta_update = 0;
 
-  set_mv_search_params(cpi);
-
   if (cpi->oxcf.pass == 2 &&
       cpi->sf.adaptive_interp_filter_search)
     cpi->sf.interp_filter_search_mask =
         setup_interp_filter_search_mask(cpi);
 
-
   // Set various flags etc to special state if it is a key frame.
   if (frame_is_intra_only(cm)) {
     // Reset the loop filter deltas and segmentation map.
@@ -3006,20 +3146,6 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi,
     }
   }
 
-  // Configure experimental use of segmentation for enhanced coding of
-  // static regions if indicated.
-  // Only allowed in second pass of two pass (as requires lagged coding)
-  // and if the relevant speed feature flag is set.
-  if (oxcf->pass == 2 && cpi->sf.static_segmentation)
-    configure_static_seg_features(cpi);
-
-  // Check if the current frame is skippable for the partition search in the
-  // second pass according to the first pass stats
-  if (cpi->sf.allow_partition_search_skip && oxcf->pass == 2 &&
-      (!cpi->use_svc || is_two_pass_svc(cpi))) {
-    cpi->partition_search_skippable_frame = is_skippable_frame(cpi);
-  }
-
   // For 1 pass CBR, check if we are dropping this frame.
   // Never drop on key frame.
   if (oxcf->pass == 0 &&
@@ -3034,31 +3160,6 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi,
 
   vp9_clear_system_state();
 
-#if CONFIG_VP9_POSTPROC
-  if (oxcf->noise_sensitivity > 0) {
-    int l = 0;
-    switch (oxcf->noise_sensitivity) {
-      case 1:
-        l = 20;
-        break;
-      case 2:
-        l = 40;
-        break;
-      case 3:
-        l = 60;
-        break;
-      case 4:
-      case 5:
-        l = 100;
-        break;
-      case 6:
-        l = 150;
-        break;
-    }
-    vp9_denoise(cpi->Source, cpi->Source, l);
-  }
-#endif
-
 #if CONFIG_INTERNAL_STATS
   {
     int i;
@@ -3067,24 +3168,10 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi,
   }
 #endif
 
-  vp9_set_speed_features(cpi);
-
-  vp9_set_rd_speed_thresholds(cpi);
-  vp9_set_rd_speed_thresholds_sub8x8(cpi);
-
-  // Decide q and q bounds.
-  q = vp9_rc_pick_q_and_bounds(cpi, &bottom_index, &top_index);
-
-  if (!frame_is_intra_only(cm)) {
-    cm->interp_filter = cpi->sf.default_interp_filter;
-    /* TODO: Decide this more intelligently */
-    vp9_set_high_precision_mv(cpi, q < HIGH_PRECISION_MV_QTHRESH);
-  }
-
   if (cpi->sf.recode_loop == DISALLOW_RECODE) {
-    encode_without_recode_loop(cpi, q);
+    encode_without_recode_loop(cpi);
   } else {
-    encode_with_recode_loop(cpi, size, dest, q, bottom_index, top_index);
+    encode_with_recode_loop(cpi, size, dest);
   }
 
 #if CONFIG_VP9_TEMPORAL_DENOISING
@@ -3227,16 +3314,6 @@ static void Pass2Encode(VP9_COMP *cpi, size_t *size,
     vp9_twopass_postencode_update(cpi);
 }
 
-static void init_motion_estimation(VP9_COMP *cpi) {
-  int y_stride = cpi->scaled_source.y_stride;
-
-  if (cpi->sf.mv.search_method == NSTEP) {
-    vp9_init3smotion_compensation(&cpi->ss_cfg, y_stride);
-  } else if (cpi->sf.mv.search_method == DIAMOND) {
-    vp9_init_dsmotion_compensation(&cpi->ss_cfg, y_stride);
-  }
-}
-
 static void check_initial_width(VP9_COMP *cpi,
 #if CONFIG_VP9_HIGHBITDEPTH
                                 int use_highbitdepth,
@@ -3255,10 +3332,11 @@ static void check_initial_width(VP9_COMP *cpi,
     alloc_ref_frame_buffers(cpi);
     alloc_util_frame_buffers(cpi);
 
-    init_motion_estimation(cpi);
+    init_motion_estimation(cpi);  // TODO(agrange) This can be removed.
 
     cpi->initial_width = cm->width;
     cpi->initial_height = cm->height;
+    cpi->initial_mbs = cm->MBs;
   }
 }
 
@@ -3400,14 +3478,13 @@ int vp9_get_compressed_data(VP9_COMP *cpi, unsigned int *frame_flags,
                             int64_t *time_stamp, int64_t *time_end, int flush) {
   const VP9EncoderConfig *const oxcf = &cpi->oxcf;
   VP9_COMMON *const cm = &cpi->common;
-  MACROBLOCKD *const xd = &cpi->mb.e_mbd;
   RATE_CONTROL *const rc = &cpi->rc;
   struct vpx_usec_timer  cmptimer;
   YV12_BUFFER_CONFIG *force_src_buffer = NULL;
   struct lookahead_entry *last_source = NULL;
   struct lookahead_entry *source = NULL;
-  MV_REFERENCE_FRAME ref_frame;
   int arf_src_index;
+  int i;
 
   if (is_two_pass_svc(cpi)) {
 #if CONFIG_SPATIAL_SVC
@@ -3546,24 +3623,11 @@ int vp9_get_compressed_data(VP9_COMP *cpi, unsigned int *frame_flags,
     vp9_restore_layer_context(cpi);
   }
 
-  // start with a 0 size frame
-  *size = 0;
-
-  /* find a free buffer for the new frame, releasing the reference previously
-   * held.
-   */
+  // Find a free buffer for the new frame, releasing the reference previously
+  // held.
   cm->frame_bufs[cm->new_fb_idx].ref_count--;
   cm->new_fb_idx = get_free_fb(cm);
 
-  // For two pass encodes analyse the first pass stats and determine
-  // the bit allocation and other parameters for this frame / group of frames.
-  if ((oxcf->pass == 2) &&
-      (!cpi->use_svc ||
-       (is_two_pass_svc(cpi) &&
-        cpi->svc.encode_empty_frame_state != ENCODING))) {
-    vp9_rc_get_second_pass_params(cpi);
-  }
-
   if (!cpi->use_svc && cpi->multi_arf_allowed) {
     if (cm->frame_type == KEY_FRAME) {
       init_buffer_indices(cpi);
@@ -3573,56 +3637,27 @@ int vp9_get_compressed_data(VP9_COMP *cpi, unsigned int *frame_flags,
     }
   }
 
-  cpi->frame_flags = *frame_flags;
-
-  if (oxcf->pass == 2 &&
-      cm->current_video_frame == 0 &&
-      oxcf->allow_spatial_resampling &&
-      oxcf->rc_mode == VPX_VBR) {
-    // Internal scaling is triggered on the first frame.
-    vp9_set_size_literal(cpi, oxcf->scaled_frame_width,
-                         oxcf->scaled_frame_height);
-  }
-
-  // Reset the frame pointers to the current frame size
-  vp9_realloc_frame_buffer(get_frame_new_buffer(cm),
-                           cm->width, cm->height,
-                           cm->subsampling_x, cm->subsampling_y,
-#if CONFIG_VP9_HIGHBITDEPTH
-                           cm->use_highbitdepth,
-#endif
-                           VP9_ENC_BORDER_IN_PIXELS, NULL, NULL, NULL);
+  // Start with a 0 size frame.
+  *size = 0;
 
-  alloc_util_frame_buffers(cpi);
-  init_motion_estimation(cpi);
+  cpi->frame_flags = *frame_flags;
 
-  for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
-    const int idx = cm->ref_frame_map[get_ref_frame_idx(cpi, ref_frame)];
-    YV12_BUFFER_CONFIG *const buf = &cm->frame_bufs[idx].buf;
-    RefBuffer *const ref_buf = &cm->frame_refs[ref_frame - 1];
-    ref_buf->buf = buf;
-    ref_buf->idx = idx;
-#if CONFIG_VP9_HIGHBITDEPTH
-    vp9_setup_scale_factors_for_frame(&ref_buf->sf,
-                                      buf->y_crop_width, buf->y_crop_height,
-                                      cm->width, cm->height,
-                                      (buf->flags & YV12_FLAG_HIGHBITDEPTH) ?
-                                          1 : 0);
-#else
-    vp9_setup_scale_factors_for_frame(&ref_buf->sf,
-                                      buf->y_crop_width, buf->y_crop_height,
-                                      cm->width, cm->height);
-#endif  // CONFIG_VP9_HIGHBITDEPTH
-    if (vp9_is_scaled(&ref_buf->sf))
-      vp9_extend_frame_borders(buf);
+  if ((oxcf->pass == 2) &&
+      (!cpi->use_svc ||
+          (is_two_pass_svc(cpi) &&
+              cpi->svc.encode_empty_frame_state != ENCODING))) {
+    vp9_rc_get_second_pass_params(cpi);
+  } else {
+    set_frame_size(cpi);
   }
 
-  set_ref_ptrs(cm, xd, LAST_FRAME, LAST_FRAME);
-
   if (oxcf->aq_mode == VARIANCE_AQ) {
     vp9_vaq_init();
   }
 
+  for (i = 0; i < MAX_REF_FRAMES; ++i)
+    cpi->scaled_ref_idx[i] = INVALID_REF_BUFFER_IDX;
+
   if (oxcf->pass == 1 &&
       (!cpi->use_svc || is_two_pass_svc(cpi))) {
     const int lossless = is_lossless_requested(oxcf);
@@ -3651,7 +3686,7 @@ int vp9_get_compressed_data(VP9_COMP *cpi, unsigned int *frame_flags,
   if (cm->refresh_frame_context)
     cm->frame_contexts[cm->frame_context_idx] = *cm->fc;
 
-  // Frame was dropped, release scaled references.
+  // No frame encoded, or frame was dropped, release scaled references.
   if (*size == 0) {
     release_scaled_references(cpi);
   }
diff --git a/vp9/encoder/vp9_encoder.h b/vp9/encoder/vp9_encoder.h
index 1e6047464..52b00e6be 100644
--- a/vp9/encoder/vp9_encoder.h
+++ b/vp9/encoder/vp9_encoder.h
@@ -44,6 +44,7 @@ extern "C" {
 #endif
 
 #define DEFAULT_GF_INTERVAL         10
+#define INVALID_REF_BUFFER_IDX      -1  // Marks an invalid reference buffer id.
 
 typedef struct {
   int nmvjointcost[MV_JOINTS];
@@ -241,7 +242,7 @@ typedef struct VP9_COMP {
   // For a still frame, this flag is set to 1 to skip partition search.
   int partition_search_skippable_frame;
 
-  int scaled_ref_idx[3];
+  int scaled_ref_idx[MAX_REF_FRAMES];
   int lst_fb_idx;
   int gld_fb_idx;
   int alt_fb_idx;
@@ -374,6 +375,10 @@ typedef struct VP9_COMP {
 
   int initial_width;
   int initial_height;
+  int initial_mbs;  // Number of MBs in the full-size frame; to be used to
+                    // normalize the firstpass stats. This will differ from the
+                    // number of MBs in the current frame when the frame is
+                    // scaled.
 
   int use_svc;
 
diff --git a/vp9/encoder/vp9_firstpass.c b/vp9/encoder/vp9_firstpass.c
index f1baf8323..5a67ef414 100644
--- a/vp9/encoder/vp9_firstpass.c
+++ b/vp9/encoder/vp9_firstpass.c
@@ -138,7 +138,7 @@ static void output_fpmb_stats(uint8_t *this_frame_mb_stats, VP9_COMMON *cm,
   struct vpx_codec_cx_pkt pkt;
   pkt.kind = VPX_CODEC_FPMB_STATS_PKT;
   pkt.data.firstpass_mb_stats.buf = this_frame_mb_stats;
-  pkt.data.firstpass_mb_stats.sz = cm->MBs * sizeof(uint8_t);
+  pkt.data.firstpass_mb_stats.sz = cm->initial_mbs * sizeof(uint8_t);
   vpx_codec_pkt_list_add(pktlist, &pkt);
 }
 #endif
@@ -483,7 +483,7 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
 
 #if CONFIG_FP_MB_STATS
   if (cpi->use_fp_mb_stats) {
-    vp9_zero_array(cpi->twopass.frame_mb_stats_buf, cm->MBs);
+    vp9_zero_array(cpi->twopass.frame_mb_stats_buf, cm->initial_mbs);
   }
 #endif
 
@@ -934,12 +934,14 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
   vp9_clear_system_state();
   {
     FIRSTPASS_STATS fps;
-    // The minimum error here insures some bit alocation to frames even
+    // The minimum error here insures some bit allocation to frames even
     // in static regions. The allocation per MB declines for larger formats
     // where the typical "real" energy per MB also falls.
     // Initial estimate here uses sqrt(mbs) to define the min_err, where the
-    // number of mbs is propotional to image area.
-    const double min_err = 200 * sqrt(cm->MBs);
+    // number of mbs is proportional to the image area.
+    const int num_mbs =
+        cpi->oxcf.allow_spatial_resampling ? cpi->initial_mbs : cpi->common.MBs;
+    const double min_err = 200 * sqrt(num_mbs);
 
     fps.frame = cm->current_video_frame;
     fps.spatial_layer_id = cpi->svc.spatial_layer_id;
@@ -947,9 +949,9 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
     fps.sr_coded_error = (double)(sr_coded_error >> 8) + min_err;
     fps.intra_error = (double)(intra_error >> 8) + min_err;
     fps.count = 1.0;
-    fps.pcnt_inter = (double)intercount / cm->MBs;
-    fps.pcnt_second_ref = (double)second_ref_count / cm->MBs;
-    fps.pcnt_neutral = (double)neutral_count / cm->MBs;
+    fps.pcnt_inter = (double)intercount / num_mbs;
+    fps.pcnt_second_ref = (double)second_ref_count / num_mbs;
+    fps.pcnt_neutral = (double)neutral_count / num_mbs;
 
     if (mvcount > 0) {
       fps.MVr = (double)sum_mvr / mvcount;
@@ -960,7 +962,7 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
       fps.MVcv = ((double)sum_mvcs - (fps.MVc * fps.MVc / mvcount)) / mvcount;
       fps.mv_in_out_count = (double)sum_in_vectors / (mvcount * 2);
       fps.new_mv_count = new_mv_count;
-      fps.pcnt_motion = (double)mvcount / cm->MBs;
+      fps.pcnt_motion = (double)mvcount / num_mbs;
     } else {
       fps.MVr = 0.0;
       fps.mvr_abs = 0.0;
@@ -1074,7 +1076,8 @@ static int get_twopass_worst_quality(const VP9_COMP *cpi,
   if (section_target_bandwidth <= 0) {
     return rc->worst_quality;  // Highest value allowed
   } else {
-    const int num_mbs = cpi->common.MBs;
+    const int num_mbs =
+        cpi->oxcf.allow_spatial_resampling ? cpi->initial_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;
@@ -1188,9 +1191,12 @@ void vp9_init_second_pass(VP9_COMP *cpi) {
 #define LOW_SR_DIFF_TRHESH 0.1
 #define SR_DIFF_MAX 128.0
 
-static double get_sr_decay_rate(const VP9_COMMON *cm,
+static double get_sr_decay_rate(const VP9_COMP *cpi,
                                 const FIRSTPASS_STATS *frame) {
-  double sr_diff = (frame->sr_coded_error - frame->coded_error) / cm->MBs;
+  const int num_mbs =
+      cpi->oxcf.allow_spatial_resampling ? cpi->initial_mbs : cpi->common.MBs;
+  double sr_diff =
+      (frame->sr_coded_error - frame->coded_error) / num_mbs;
   double sr_decay = 1.0;
   const double motion_amplitude_factor =
     frame->pcnt_motion * ((frame->mvc_abs + frame->mvr_abs) / 2);
@@ -1207,19 +1213,19 @@ static double get_sr_decay_rate(const VP9_COMMON *cm,
 
 // 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,
+static double get_zero_motion_factor(const VP9_COMP *cpi,
                                      const FIRSTPASS_STATS *frame) {
   const double zero_motion_pct = frame->pcnt_inter -
                                  frame->pcnt_motion;
-  double sr_decay = get_sr_decay_rate(cm, frame);
+  double sr_decay = get_sr_decay_rate(cpi, frame);
   return MIN(sr_decay, zero_motion_pct);
 }
 
 #define ZM_POWER_FACTOR 0.75
 
-static double get_prediction_decay_rate(const VP9_COMMON *cm,
+static double get_prediction_decay_rate(const VP9_COMP *cpi,
                                         const FIRSTPASS_STATS *next_frame) {
-  const double sr_decay_rate = get_sr_decay_rate(cm, next_frame);
+  const double sr_decay_rate = get_sr_decay_rate(cpi, next_frame);
   const double zero_motion_factor =
     (0.95 * pow((next_frame->pcnt_inter - next_frame->pcnt_motion),
                 ZM_POWER_FACTOR));
@@ -1314,9 +1320,11 @@ static double calc_frame_boost(VP9_COMP *cpi,
     vp9_convert_qindex_to_q(cpi->rc.avg_frame_qindex[INTER_FRAME],
                             cpi->common.bit_depth);
   const double boost_correction = MIN((0.5 + (lq * 0.015)), 1.5);
+  const int num_mbs =
+      cpi->oxcf.allow_spatial_resampling ? cpi->initial_mbs : cpi->common.MBs;
 
   // Underlying boost factor is based on inter error ratio.
-  frame_boost = (BASELINE_ERR_PER_MB * cpi->common.MBs) /
+  frame_boost = (BASELINE_ERR_PER_MB * num_mbs) /
                 DOUBLE_DIVIDE_CHECK(this_frame->coded_error);
   frame_boost = frame_boost * BOOST_FACTOR * boost_correction;
 
@@ -1365,7 +1373,7 @@ static int calc_arf_boost(VP9_COMP *cpi, int offset,
 
     // Accumulate the effect of prediction quality decay.
     if (!flash_detected) {
-      decay_accumulator *= get_prediction_decay_rate(&cpi->common, this_frame);
+      decay_accumulator *= get_prediction_decay_rate(cpi, this_frame);
       decay_accumulator = decay_accumulator < MIN_DECAY_FACTOR
                           ? MIN_DECAY_FACTOR : decay_accumulator;
     }
@@ -1404,7 +1412,7 @@ static int calc_arf_boost(VP9_COMP *cpi, int offset,
 
     // Cumulative effect of prediction quality decay.
     if (!flash_detected) {
-      decay_accumulator *= get_prediction_decay_rate(&cpi->common, this_frame);
+      decay_accumulator *= get_prediction_decay_rate(cpi, this_frame);
       decay_accumulator = decay_accumulator < MIN_DECAY_FACTOR
                               ? MIN_DECAY_FACTOR : decay_accumulator;
     }
@@ -1723,7 +1731,8 @@ static void define_gf_group(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
     gf_group_err -= gf_first_frame_err;
 
   // Motion breakout threshold for loop below depends on image size.
-  mv_ratio_accumulator_thresh = (cpi->common.width + cpi->common.height) / 4.0;
+  mv_ratio_accumulator_thresh =
+      (cpi->common.height + cpi->common.width) / 4.0;
 
   // Set a maximum and minimum interval for the GF group.
   // If the image appears almost completely static we can extend beyond this.
@@ -1775,14 +1784,14 @@ static void define_gf_group(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
     // 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);
+      loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
 
       decay_accumulator = decay_accumulator * loop_decay_rate;
 
       // Monitor for static sections.
       zero_motion_accumulator =
         MIN(zero_motion_accumulator,
-            get_zero_motion_factor(&cpi->common, &next_frame));
+            get_zero_motion_factor(cpi, &next_frame));
 
       // Break clause to detect very still sections after motion. For example,
       // a static image after a fade or other transition.
@@ -2048,8 +2057,7 @@ static void find_next_key_frame(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
         break;
 
       // How fast is the prediction quality decaying?
-      loop_decay_rate = get_prediction_decay_rate(&cpi->common,
-                                                  twopass->stats_in);
+      loop_decay_rate = get_prediction_decay_rate(cpi, twopass->stats_in);
 
       // We want to know something about the recent past... rather than
       // as used elsewhere where we are concerned with decay in prediction
@@ -2160,7 +2168,7 @@ static void find_next_key_frame(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
     // Monitor for static sections.
     zero_motion_accumulator =
       MIN(zero_motion_accumulator,
-          get_zero_motion_factor(&cpi->common, &next_frame));
+          get_zero_motion_factor(cpi, &next_frame));
 
     // Not all frames in the group are necessarily used in calculating boost.
     if ((i <= rc->max_gf_interval) ||
@@ -2171,7 +2179,7 @@ static void find_next_key_frame(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
       // How fast is prediction quality decaying.
       if (!detect_flash(twopass, 0)) {
         const double loop_decay_rate =
-          get_prediction_decay_rate(&cpi->common, &next_frame);
+          get_prediction_decay_rate(cpi, &next_frame);
         decay_accumulator *= loop_decay_rate;
         decay_accumulator = MAX(decay_accumulator, MIN_DECAY_FACTOR);
         av_decay_accumulator += decay_accumulator;
@@ -2295,6 +2303,24 @@ void configure_buffer_updates(VP9_COMP *cpi) {
   }
 }
 
+int is_skippable_frame(const VP9_COMP *cpi) {
+  // If the current frame does not have non-zero motion vector detected in the
+  // first  pass, and so do its previous and forward frames, then this frame
+  // can be skipped for partition check, and the partition size is assigned
+  // according to the variance
+  const SVC *const svc = &cpi->svc;
+  const TWO_PASS *const twopass = is_two_pass_svc(cpi) ?
+      &svc->layer_context[svc->spatial_layer_id].twopass : &cpi->twopass;
+
+  return (!frame_is_intra_only(&cpi->common) &&
+    twopass->stats_in - 2 > twopass->stats_in_start &&
+    twopass->stats_in < twopass->stats_in_end &&
+    (twopass->stats_in - 1)->pcnt_inter - (twopass->stats_in - 1)->pcnt_motion
+    == 1 &&
+    (twopass->stats_in - 2)->pcnt_inter - (twopass->stats_in - 2)->pcnt_motion
+    == 1 &&
+    twopass->stats_in->pcnt_inter - twopass->stats_in->pcnt_motion == 1);
+}
 
 void vp9_rc_get_second_pass_params(VP9_COMP *cpi) {
   VP9_COMMON *const cm = &cpi->common;
@@ -2329,11 +2355,6 @@ void vp9_rc_get_second_pass_params(VP9_COMP *cpi) {
     target_rate = vp9_rc_clamp_pframe_target_size(cpi, target_rate);
     rc->base_frame_target = target_rate;
 
-    // Correction to rate target based on prior over or under shoot.
-    if (cpi->oxcf.rc_mode == VPX_VBR)
-      vbr_rate_correction(cpi, &target_rate, rc->vbr_bits_off_target);
-
-    vp9_rc_set_frame_target(cpi, target_rate);
     cm->frame_type = INTER_FRAME;
 
     if (lc != NULL) {
@@ -2347,6 +2368,13 @@ void vp9_rc_get_second_pass_params(VP9_COMP *cpi) {
       }
     }
 
+    // Do the firstpass stats indicate that this frame is skippable for the
+    // partition search?
+    if (cpi->sf.allow_partition_search_skip &&
+        cpi->oxcf.pass == 2 && (!cpi->use_svc || is_two_pass_svc(cpi))) {
+      cpi->partition_search_skippable_frame = is_skippable_frame(cpi);
+    }
+
     return;
   }
 
@@ -2377,8 +2405,7 @@ void vp9_rc_get_second_pass_params(VP9_COMP *cpi) {
   this_frame_copy = this_frame;
 
   // Keyframe and section processing.
-  if (rc->frames_to_key == 0 ||
-      (cpi->frame_flags & FRAMEFLAGS_KEY)) {
+  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 {
@@ -2431,6 +2458,13 @@ void vp9_rc_get_second_pass_params(VP9_COMP *cpi) {
 
   configure_buffer_updates(cpi);
 
+  // Do the firstpass stats indicate that this frame is skippable for the
+  // partition search?
+  if (cpi->sf.allow_partition_search_skip && cpi->oxcf.pass == 2 &&
+      (!cpi->use_svc || is_two_pass_svc(cpi))) {
+    cpi->partition_search_skippable_frame = is_skippable_frame(cpi);
+  }
+
   target_rate = gf_group->bit_allocation[gf_group->index];
   if (cpi->common.frame_type == KEY_FRAME)
     target_rate = vp9_rc_clamp_iframe_target_size(cpi, target_rate);
@@ -2439,12 +2473,6 @@ void vp9_rc_get_second_pass_params(VP9_COMP *cpi) {
 
   rc->base_frame_target = target_rate;
 
-  // Correction to rate target based on prior over or under shoot.
-  if (cpi->oxcf.rc_mode == VPX_VBR)
-    vbr_rate_correction(cpi, &target_rate, rc->vbr_bits_off_target);
-
-  vp9_rc_set_frame_target(cpi, target_rate);
-
   // Update the total stats remaining structure.
   subtract_stats(&twopass->total_left_stats, &this_frame);
 }