Move frame re-sizing into the recode loop

The point at which frames are scaled to their
coded dimensions is moved into the re-code loop.

This is in preparation for a further patch that
will add logic into the re-code loop to reduce
the coded frame size if the encoder is struggling
to hit the target data rate at the native frame
size.

Change-Id: Ie4131f5ec6fb93148879f6ce96123296442bf2d1

1 files changed, 254 insertions, 219 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);
   }