av1/encoder/svc_layercontext.c - aom - Git at Google

 /*
  *  Copyright (c) 2019, Alliance for Open Media. 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 <math.h>

 #include "av1/encoder/encoder.h"
 #include "av1/encoder/encoder_alloc.h"

 static void swap_ptr(void *a, void *b) {
   void **a_p = (void **)a;
   void **b_p = (void **)b;
   void *c = *a_p;
   *a_p = *b_p;
   *b_p = c;
 }

 void av1_init_layer_context(AV1_COMP *const cpi) {
   AV1_COMMON *const cm = &cpi->common;
   const AV1EncoderConfig *const oxcf = &cpi->oxcf;
   SVC *const svc = &cpi->svc;
   int mi_rows = cpi->common.mi_params.mi_rows;
   int mi_cols = cpi->common.mi_params.mi_cols;
   svc->base_framerate = 30.0;
   svc->current_superframe = 0;
   svc->force_zero_mode_spatial_ref = 1;
   svc->num_encoded_top_layer = 0;
   svc->use_flexible_mode = 0;

   for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
     for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
       int layer = LAYER_IDS_TO_IDX(sl, tl, svc->number_temporal_layers);
       LAYER_CONTEXT *const lc = &svc->layer_context[layer];
       RATE_CONTROL *const lrc = &lc->rc;
       PRIMARY_RATE_CONTROL *const lp_rc = &lc->p_rc;
       lrc->ni_av_qi = oxcf->rc_cfg.worst_allowed_q;
       lp_rc->total_actual_bits = 0;
       lrc->ni_tot_qi = 0;
       lp_rc->tot_q = 0.0;
       lp_rc->avg_q = 0.0;
       lp_rc->ni_frames = 0;
       lrc->decimation_count = 0;
       lrc->decimation_factor = 0;
       lrc->worst_quality = av1_quantizer_to_qindex(lc->max_q);
       lrc->best_quality = av1_quantizer_to_qindex(lc->min_q);
       lrc->rtc_external_ratectrl = 0;
       for (int i = 0; i < RATE_FACTOR_LEVELS; ++i) {
         lp_rc->rate_correction_factors[i] = 1.0;
       }
       lc->target_bandwidth = lc->layer_target_bitrate;
       lp_rc->last_q[INTER_FRAME] = lrc->worst_quality;
       lp_rc->avg_frame_qindex[INTER_FRAME] = lrc->worst_quality;
       lp_rc->avg_frame_qindex[KEY_FRAME] = lrc->worst_quality;
       lp_rc->buffer_level =
           oxcf->rc_cfg.starting_buffer_level_ms * lc->target_bandwidth / 1000;
       lp_rc->bits_off_target = lp_rc->buffer_level;
       // Initialize the cyclic refresh parameters. If spatial layers are used
       // (i.e., ss_number_layers > 1), these need to be updated per spatial
       // layer. Cyclic refresh is only applied on base temporal layer.
       if (svc->number_spatial_layers > 1 && tl == 0) {
         lc->sb_index = 0;
         lc->actual_num_seg1_blocks = 0;
         lc->actual_num_seg2_blocks = 0;
         lc->counter_encode_maxq_scene_change = 0;
         if (lc->map) aom_free(lc->map);
         CHECK_MEM_ERROR(cm, lc->map,
                         aom_calloc(mi_rows * mi_cols, sizeof(*lc->map)));
       }
     }
     svc->downsample_filter_type[sl] = BILINEAR;
     svc->downsample_filter_phase[sl] = 8;
   }
   if (svc->number_spatial_layers == 3) {
     svc->downsample_filter_type[0] = EIGHTTAP_SMOOTH;
   }
   svc->ref_frame_comp[0] = 0;
   svc->ref_frame_comp[1] = 0;
   svc->ref_frame_comp[2] = 0;
 }

 // Update the layer context from a change_config() call.
 void av1_update_layer_context_change_config(AV1_COMP *const cpi,
                                             const int64_t target_bandwidth) {
   const RATE_CONTROL *const rc = &cpi->rc;
   const PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;
   SVC *const svc = &cpi->svc;
   int layer = 0;
   int64_t spatial_layer_target = 0;
   float bitrate_alloc = 1.0;
   for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
     for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
       layer = LAYER_IDS_TO_IDX(sl, tl, svc->number_temporal_layers);
       LAYER_CONTEXT *const lc = &svc->layer_context[layer];
       svc->layer_context[layer].target_bandwidth = lc->layer_target_bitrate;
     }
     spatial_layer_target = svc->layer_context[layer].target_bandwidth;
     for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
       LAYER_CONTEXT *const lc =
           &svc->layer_context[sl * svc->number_temporal_layers + tl];
       RATE_CONTROL *const lrc = &lc->rc;
       PRIMARY_RATE_CONTROL *const lp_rc = &lc->p_rc;
       lc->spatial_layer_target_bandwidth = spatial_layer_target;
       bitrate_alloc = (float)lc->target_bandwidth / target_bandwidth;
       lp_rc->starting_buffer_level =
           (int64_t)(p_rc->starting_buffer_level * bitrate_alloc);
       lp_rc->optimal_buffer_level =
           (int64_t)(p_rc->optimal_buffer_level * bitrate_alloc);
       lp_rc->maximum_buffer_size =
           (int64_t)(p_rc->maximum_buffer_size * bitrate_alloc);
       lp_rc->bits_off_target =
           AOMMIN(lp_rc->bits_off_target, lp_rc->maximum_buffer_size);
       lp_rc->buffer_level =
           AOMMIN(lp_rc->buffer_level, lp_rc->maximum_buffer_size);
       lc->framerate = cpi->framerate / lc->framerate_factor;
       lrc->avg_frame_bandwidth =
           (int)round(lc->target_bandwidth / lc->framerate);
       lrc->max_frame_bandwidth = rc->max_frame_bandwidth;
       lrc->rtc_external_ratectrl = rc->rtc_external_ratectrl;
       lrc->worst_quality = av1_quantizer_to_qindex(lc->max_q);
       lrc->best_quality = av1_quantizer_to_qindex(lc->min_q);
     }
   }
 }

 /*!\brief Return layer context for current layer.
  *
  * \ingroup rate_control
  * \param[in]       cpi   Top level encoder structure
  *
  * \return LAYER_CONTEXT for current layer.
  */
 static LAYER_CONTEXT *get_layer_context(AV1_COMP *const cpi) {
   return &cpi->svc.layer_context[cpi->svc.spatial_layer_id *
                                      cpi->svc.number_temporal_layers +
                                  cpi->svc.temporal_layer_id];
 }

 void av1_update_temporal_layer_framerate(AV1_COMP *const cpi) {
   SVC *const svc = &cpi->svc;
   LAYER_CONTEXT *const lc = get_layer_context(cpi);
   RATE_CONTROL *const lrc = &lc->rc;
   const int tl = svc->temporal_layer_id;
   lc->framerate = cpi->framerate / lc->framerate_factor;
   lrc->avg_frame_bandwidth = (int)round(lc->target_bandwidth / lc->framerate);
   lrc->max_frame_bandwidth = cpi->rc.max_frame_bandwidth;
   // Update the average layer frame size (non-cumulative per-frame-bw).
   if (tl == 0) {
     lc->avg_frame_size = lrc->avg_frame_bandwidth;
   } else {
     int prev_layer = svc->spatial_layer_id * svc->number_temporal_layers +
                      svc->temporal_layer_id - 1;
     LAYER_CONTEXT *const lcprev = &svc->layer_context[prev_layer];
     const double prev_layer_framerate =
         cpi->framerate / lcprev->framerate_factor;
     const int64_t prev_layer_target_bandwidth = lcprev->layer_target_bitrate;
     lc->avg_frame_size =
         (int)round((lc->target_bandwidth - prev_layer_target_bandwidth) /
                    (lc->framerate - prev_layer_framerate));
   }
 }

 void av1_restore_layer_context(AV1_COMP *const cpi) {
   SVC *const svc = &cpi->svc;
   const AV1_COMMON *const cm = &cpi->common;
   LAYER_CONTEXT *const lc = get_layer_context(cpi);
   const int old_frame_since_key = cpi->rc.frames_since_key;
   const int old_frame_to_key = cpi->rc.frames_to_key;
   // Restore layer rate control.
   cpi->rc = lc->rc;
   cpi->ppi->p_rc = lc->p_rc;
   cpi->oxcf.rc_cfg.target_bandwidth = lc->target_bandwidth;
   cpi->gf_frame_index = 0;
   cpi->mv_search_params.max_mv_magnitude = lc->max_mv_magnitude;
   if (cpi->mv_search_params.max_mv_magnitude == 0)
     cpi->mv_search_params.max_mv_magnitude = AOMMAX(cm->width, cm->height);
   // Reset the frames_since_key and frames_to_key counters to their values
   // before the layer restore. Keep these defined for the stream (not layer).
   cpi->rc.frames_since_key = old_frame_since_key;
   cpi->rc.frames_to_key = old_frame_to_key;
   // For spatial-svc, allow cyclic-refresh to be applied on the spatial layers,
   // for the base temporal layer.
   if (cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ &&
       svc->number_spatial_layers > 1 && svc->temporal_layer_id == 0) {
     CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
     swap_ptr(&cr->map, &lc->map);
     cr->sb_index = lc->sb_index;
     cr->actual_num_seg1_blocks = lc->actual_num_seg1_blocks;
     cr->actual_num_seg2_blocks = lc->actual_num_seg2_blocks;
   }
   svc->skip_mvsearch_last = 0;
   svc->skip_mvsearch_gf = 0;
   // For each reference (LAST/GOLDEN) set the skip_mvsearch_last/gf frame flags.
   // This is to skip searching mv for that reference if it was last
   // refreshed (i.e., buffer slot holding that reference was refreshed) on the
   // previous spatial layer(s) at the same time (current_superframe).
   if (svc->set_ref_frame_config && svc->force_zero_mode_spatial_ref) {
     int ref_frame_idx = svc->ref_idx[LAST_FRAME - 1];
     if (svc->buffer_time_index[ref_frame_idx] == svc->current_superframe &&
         svc->buffer_spatial_layer[ref_frame_idx] <= svc->spatial_layer_id - 1)
       svc->skip_mvsearch_last = 1;
     ref_frame_idx = svc->ref_idx[GOLDEN_FRAME - 1];
     if (svc->buffer_time_index[ref_frame_idx] == svc->current_superframe &&
         svc->buffer_spatial_layer[ref_frame_idx] <= svc->spatial_layer_id - 1)
       svc->skip_mvsearch_gf = 1;
   }
 }

 void av1_save_layer_context(AV1_COMP *const cpi) {
   SVC *const svc = &cpi->svc;
   const AV1_COMMON *const cm = &cpi->common;
   LAYER_CONTEXT *lc = get_layer_context(cpi);
   lc->rc = cpi->rc;
   lc->p_rc = cpi->ppi->p_rc;
   lc->target_bandwidth = (int)cpi->oxcf.rc_cfg.target_bandwidth;
   lc->group_index = cpi->gf_frame_index;
   lc->max_mv_magnitude = cpi->mv_search_params.max_mv_magnitude;
   if (svc->spatial_layer_id == 0) svc->base_framerate = cpi->framerate;
   // For spatial-svc, allow cyclic-refresh to be applied on the spatial layers,
   // for the base temporal layer.
   if (cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ &&
       cpi->svc.number_spatial_layers > 1 && svc->temporal_layer_id == 0) {
     CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
     signed char *temp = lc->map;
     lc->map = cr->map;
     cr->map = temp;
     lc->sb_index = cr->sb_index;
     lc->actual_num_seg1_blocks = cr->actual_num_seg1_blocks;
     lc->actual_num_seg2_blocks = cr->actual_num_seg2_blocks;
   }
   // For any buffer slot that is refreshed, update it with
   // the spatial_layer_id and the current_superframe.
   if (cpi->common.current_frame.frame_type == KEY_FRAME) {
     // All slots are refreshed on KEY.
     for (unsigned int i = 0; i < REF_FRAMES; i++) {
       svc->buffer_time_index[i] = svc->current_superframe;
       svc->buffer_spatial_layer[i] = svc->spatial_layer_id;
     }
   } else if (cpi->svc.set_ref_frame_config) {
     for (unsigned int i = 0; i < INTER_REFS_PER_FRAME; i++) {
       int ref_frame_map_idx = svc->ref_idx[i];
       if (cpi->svc.refresh[ref_frame_map_idx]) {
         svc->buffer_time_index[ref_frame_map_idx] = svc->current_superframe;
         svc->buffer_spatial_layer[ref_frame_map_idx] = svc->spatial_layer_id;
       }
     }
   }
   for (unsigned int i = 0; i < REF_FRAMES; i++) {
     if (frame_is_intra_only(cm) ||
         cm->current_frame.refresh_frame_flags & (1 << i)) {
       svc->spatial_layer_fb[i] = svc->spatial_layer_id;
       svc->temporal_layer_fb[i] = svc->temporal_layer_id;
     }
   }
   if (svc->spatial_layer_id == svc->number_spatial_layers - 1)
     svc->current_superframe++;
 }

 int av1_svc_primary_ref_frame(const AV1_COMP *const cpi) {
   const SVC *const svc = &cpi->svc;
   const AV1_COMMON *const cm = &cpi->common;
   int fb_idx = -1;
   int primary_ref_frame = PRIMARY_REF_NONE;
   // Set the primary_ref_frame to LAST_FRAME if that buffer slot for LAST
   // was last updated on a lower temporal layer (or base TL0) and for the
   // same spatial layer. For RTC patterns this allows for continued decoding
   // when set of enhancement layers are dropped (continued decoding starting
   // at next base TL0), so error_resilience can be off/0 for all layers.
   fb_idx = get_ref_frame_map_idx(cm, LAST_FRAME);
   if (svc->spatial_layer_fb[fb_idx] == svc->spatial_layer_id &&
       (svc->temporal_layer_fb[fb_idx] < svc->temporal_layer_id ||
        svc->temporal_layer_fb[fb_idx] == 0)) {
     primary_ref_frame = 0;  // LAST_FRAME
   }
   return primary_ref_frame;
 }

 void av1_free_svc_cyclic_refresh(AV1_COMP *const cpi) {
   SVC *const svc = &cpi->svc;
   for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
     for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
       int layer = LAYER_IDS_TO_IDX(sl, tl, svc->number_temporal_layers);
       LAYER_CONTEXT *const lc = &svc->layer_context[layer];
       if (lc->map) aom_free(lc->map);
     }
   }
 }

 void av1_svc_reset_temporal_layers(AV1_COMP *const cpi, int is_key) {
   SVC *const svc = &cpi->svc;
   LAYER_CONTEXT *lc = NULL;
   for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
     for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
       lc = &cpi->svc.layer_context[sl * svc->number_temporal_layers + tl];
       if (is_key) lc->frames_from_key_frame = 0;
     }
   }
   av1_update_temporal_layer_framerate(cpi);
   av1_restore_layer_context(cpi);
 }

 void av1_get_layer_resolution(const int width_org, const int height_org,
                               const int num, const int den, int *width_out,
                               int *height_out) {
   int w, h;
   if (width_out == NULL || height_out == NULL || den == 0) return;
   w = width_org * num / den;
   h = height_org * num / den;
   // Make height and width even.
   w += w % 2;
   h += h % 2;
   *width_out = w;
   *height_out = h;
 }

 void av1_one_pass_cbr_svc_start_layer(AV1_COMP *const cpi) {
   SVC *const svc = &cpi->svc;
   LAYER_CONTEXT *lc = NULL;
   int width = 0, height = 0;
   lc = &svc->layer_context[svc->spatial_layer_id * svc->number_temporal_layers +
                            svc->temporal_layer_id];
   av1_get_layer_resolution(cpi->oxcf.frm_dim_cfg.width,
                            cpi->oxcf.frm_dim_cfg.height, lc->scaling_factor_num,
                            lc->scaling_factor_den, &width, &height);
   // Use Eightap_smooth for low resolutions.
   if (width * height <= 320 * 240)
     svc->downsample_filter_type[svc->spatial_layer_id] = EIGHTTAP_SMOOTH;

   cpi->common.width = width;
   cpi->common.height = height;
   alloc_mb_mode_info_buffers(cpi);
   av1_update_frame_size(cpi);
   if (svc->spatial_layer_id == 0) svc->high_source_sad_superframe = 0;
 }

 enum {
   SVC_LAST_FRAME = 0,
   SVC_LAST2_FRAME,
   SVC_LAST3_FRAME,
   SVC_GOLDEN_FRAME,
   SVC_BWDREF_FRAME,
   SVC_ALTREF2_FRAME,
   SVC_ALTREF_FRAME
 };

 // For fixed svc mode: fixed pattern is set based on the number of
 // spatial and temporal layers, and the ksvc_fixed_mode.
 void av1_set_svc_fixed_mode(AV1_COMP *const cpi) {
   SVC *const svc = &cpi->svc;
   int i;
   assert(svc->use_flexible_mode == 0);
   // Fixed SVC mode only supports at most 3 spatial or temporal layers.
   assert(svc->number_spatial_layers >= 1 && svc->number_spatial_layers <= 3 &&
          svc->number_temporal_layers >= 1 && svc->number_temporal_layers <= 3);
   svc->set_ref_frame_config = 1;
   int superframe_cnt = svc->current_superframe;
   // Set the reference map buffer idx for the 7 references:
   // LAST_FRAME (0), LAST2_FRAME(1), LAST3_FRAME(2), GOLDEN_FRAME(3),
   // BWDREF_FRAME(4), ALTREF2_FRAME(5), ALTREF_FRAME(6).
   for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = i;
   for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->reference[i] = 0;
   for (i = 0; i < REF_FRAMES; i++) svc->refresh[i] = 0;
   // Always reference LAST, and reference GOLDEN on SL > 0.
   // For KSVC: GOLDEN reference will be removed on INTER_FRAMES later
   // when frame_type is set.
   svc->reference[SVC_LAST_FRAME] = 1;
   if (svc->spatial_layer_id > 0) svc->reference[SVC_GOLDEN_FRAME] = 1;
   if (svc->temporal_layer_id == 0) {
     // Base temporal layer.
     if (svc->spatial_layer_id == 0) {
       // Set all buffer_idx to 0. Update slot 0 (LAST).
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
       svc->refresh[0] = 1;
     } else if (svc->spatial_layer_id == 1) {
       // Set buffer_idx for LAST to slot 1, GOLDEN (and all other refs) to
       // slot 0. Update slot 1 (LAST).
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
       svc->ref_idx[SVC_LAST_FRAME] = 1;
       svc->refresh[1] = 1;
     } else if (svc->spatial_layer_id == 2) {
       // Set buffer_idx for LAST to slot 2, GOLDEN (and all other refs) to
       // slot 1. Update slot 2 (LAST).
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 1;
       svc->ref_idx[SVC_LAST_FRAME] = 2;
       svc->refresh[2] = 1;
     }
   } else if (svc->temporal_layer_id == 2 && (superframe_cnt - 1) % 4 == 0) {
     // First top temporal enhancement layer.
     if (svc->spatial_layer_id == 0) {
       // Reference LAST (slot 0).
       // Set GOLDEN to slot 3 and update slot 3.
       // Set all other buffer_idx to slot 0.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
       if (svc->spatial_layer_id < svc->number_spatial_layers - 1) {
         svc->ref_idx[SVC_GOLDEN_FRAME] = 3;
         svc->refresh[3] = 1;
       }
     } else if (svc->spatial_layer_id == 1) {
       // Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 1,
       // GOLDEN (and all other refs) to slot 3.
       // Set LAST2 to slot 4 and Update slot 4.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 3;
       svc->ref_idx[SVC_LAST_FRAME] = 1;
       if (svc->spatial_layer_id < svc->number_spatial_layers - 1) {
         svc->ref_idx[SVC_LAST2_FRAME] = 4;
         svc->refresh[4] = 1;
       }
     } else if (svc->spatial_layer_id == 2) {
       // Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 2,
       // GOLDEN (and all other refs) to slot 4.
       // No update.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 4;
       svc->ref_idx[SVC_LAST_FRAME] = 2;
     }
   } else if (svc->temporal_layer_id == 1) {
     // Middle temporal enhancement layer.
     if (svc->spatial_layer_id == 0) {
       // Reference LAST.
       // Set all buffer_idx to 0.
       // Set GOLDEN to slot 5 and update slot 5.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
       if (svc->temporal_layer_id < svc->number_temporal_layers - 1) {
         svc->ref_idx[SVC_GOLDEN_FRAME] = 5;
         svc->refresh[5] = 1;
       }
     } else if (svc->spatial_layer_id == 1) {
       // Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 1,
       // GOLDEN (and all other refs) to slot 5.
       // Set LAST3 to slot 6 and update slot 6.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 5;
       svc->ref_idx[SVC_LAST_FRAME] = 1;
       if (svc->temporal_layer_id < svc->number_temporal_layers - 1) {
         svc->ref_idx[SVC_LAST3_FRAME] = 6;
         svc->refresh[6] = 1;
       }
     } else if (svc->spatial_layer_id == 2) {
       // Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 2,
       // GOLDEN (and all other refs) to slot 6.
       // Set LAST3 to slot 7 and update slot 7.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 6;
       svc->ref_idx[SVC_LAST_FRAME] = 2;
       if (svc->temporal_layer_id < svc->number_temporal_layers - 1) {
         svc->ref_idx[SVC_LAST3_FRAME] = 7;
         svc->refresh[7] = 1;
       }
     }
   } else if (svc->temporal_layer_id == 2 && (superframe_cnt - 3) % 4 == 0) {
     // Second top temporal enhancement layer.
     if (svc->spatial_layer_id == 0) {
       // Set LAST to slot 5 and reference LAST.
       // Set GOLDEN to slot 3 and update slot 3.
       // Set all other buffer_idx to 0.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
       svc->ref_idx[SVC_LAST_FRAME] = 5;
       if (svc->spatial_layer_id < svc->number_spatial_layers - 1) {
         svc->ref_idx[SVC_GOLDEN_FRAME] = 3;
         svc->refresh[3] = 1;
       }
     } else if (svc->spatial_layer_id == 1) {
       // Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 6,
       // GOLDEN to slot 3. Set LAST2 to slot 4 and update slot 4.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
       svc->ref_idx[SVC_LAST_FRAME] = 6;
       svc->ref_idx[SVC_GOLDEN_FRAME] = 3;
       if (svc->spatial_layer_id < svc->number_spatial_layers - 1) {
         svc->ref_idx[SVC_LAST2_FRAME] = 4;
         svc->refresh[4] = 1;
       }
     } else if (svc->spatial_layer_id == 2) {
       // Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 7,
       // GOLDEN to slot 4. No update.
       for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
       svc->ref_idx[SVC_LAST_FRAME] = 7;
       svc->ref_idx[SVC_GOLDEN_FRAME] = 4;
     }
   }
 }

 void av1_svc_check_reset_layer_rc_flag(AV1_COMP *const cpi) {
   SVC *const svc = &cpi->svc;
   for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
     // Check for reset based on avg_frame_bandwidth for spatial layer sl.
     int layer = LAYER_IDS_TO_IDX(sl, svc->number_temporal_layers - 1,
                                  svc->number_temporal_layers);
     LAYER_CONTEXT *lc = &svc->layer_context[layer];
     RATE_CONTROL *lrc = &lc->rc;
     if (lrc->avg_frame_bandwidth > (3 * lrc->prev_avg_frame_bandwidth >> 1) ||
         lrc->avg_frame_bandwidth < (lrc->prev_avg_frame_bandwidth >> 1)) {
       // Reset for all temporal layers with spatial layer sl.
       for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
         int layer2 = LAYER_IDS_TO_IDX(sl, tl, svc->number_temporal_layers);
         LAYER_CONTEXT *lc2 = &svc->layer_context[layer2];
         RATE_CONTROL *lrc2 = &lc2->rc;
         PRIMARY_RATE_CONTROL *lp_rc2 = &lc2->p_rc;
         PRIMARY_RATE_CONTROL *const lp_rc = &lc2->p_rc;
         lrc2->rc_1_frame = 0;
         lrc2->rc_2_frame = 0;
         lp_rc2->bits_off_target = lp_rc->optimal_buffer_level;
         lp_rc2->buffer_level = lp_rc->optimal_buffer_level;
       }
     }
   }
 }
	/*
	* Copyright (c) 2019, Alliance for Open Media. 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 <math.h>

	#include "av1/encoder/encoder.h"
	#include "av1/encoder/encoder_alloc.h"

	static void swap_ptr(void a, void b) {
	void a_p = (void )a;
	void b_p = (void )b;
	void c = a_p;
	a_p = b_p;
	*b_p = c;
	}

	void av1_init_layer_context(AV1_COMP *const cpi) {
	AV1_COMMON *const cm = &cpi->common;
	const AV1EncoderConfig *const oxcf = &cpi->oxcf;
	SVC *const svc = &cpi->svc;
	int mi_rows = cpi->common.mi_params.mi_rows;
	int mi_cols = cpi->common.mi_params.mi_cols;
	svc->base_framerate = 30.0;
	svc->current_superframe = 0;
	svc->force_zero_mode_spatial_ref = 1;
	svc->num_encoded_top_layer = 0;
	svc->use_flexible_mode = 0;

	for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
	for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
	int layer = LAYER_IDS_TO_IDX(sl, tl, svc->number_temporal_layers);
	LAYER_CONTEXT *const lc = &svc->layer_context[layer];
	RATE_CONTROL *const lrc = &lc->rc;
	PRIMARY_RATE_CONTROL *const lp_rc = &lc->p_rc;
	lrc->ni_av_qi = oxcf->rc_cfg.worst_allowed_q;
	lp_rc->total_actual_bits = 0;
	lrc->ni_tot_qi = 0;
	lp_rc->tot_q = 0.0;
	lp_rc->avg_q = 0.0;
	lp_rc->ni_frames = 0;
	lrc->decimation_count = 0;
	lrc->decimation_factor = 0;
	lrc->worst_quality = av1_quantizer_to_qindex(lc->max_q);
	lrc->best_quality = av1_quantizer_to_qindex(lc->min_q);
	lrc->rtc_external_ratectrl = 0;
	for (int i = 0; i < RATE_FACTOR_LEVELS; ++i) {
	lp_rc->rate_correction_factors[i] = 1.0;
	}
	lc->target_bandwidth = lc->layer_target_bitrate;
	lp_rc->last_q[INTER_FRAME] = lrc->worst_quality;
	lp_rc->avg_frame_qindex[INTER_FRAME] = lrc->worst_quality;
	lp_rc->avg_frame_qindex[KEY_FRAME] = lrc->worst_quality;
	lp_rc->buffer_level =
	oxcf->rc_cfg.starting_buffer_level_ms * lc->target_bandwidth / 1000;
	lp_rc->bits_off_target = lp_rc->buffer_level;
	// Initialize the cyclic refresh parameters. If spatial layers are used
	// (i.e., ss_number_layers > 1), these need to be updated per spatial
	// layer. Cyclic refresh is only applied on base temporal layer.
	if (svc->number_spatial_layers > 1 && tl == 0) {
	lc->sb_index = 0;
	lc->actual_num_seg1_blocks = 0;
	lc->actual_num_seg2_blocks = 0;
	lc->counter_encode_maxq_scene_change = 0;
	if (lc->map) aom_free(lc->map);
	CHECK_MEM_ERROR(cm, lc->map,
	aom_calloc(mi_rows * mi_cols, sizeof(*lc->map)));
	}
	}
	svc->downsample_filter_type[sl] = BILINEAR;
	svc->downsample_filter_phase[sl] = 8;
	}
	if (svc->number_spatial_layers == 3) {
	svc->downsample_filter_type[0] = EIGHTTAP_SMOOTH;
	}
	svc->ref_frame_comp[0] = 0;
	svc->ref_frame_comp[1] = 0;
	svc->ref_frame_comp[2] = 0;
	}

	// Update the layer context from a change_config() call.
	void av1_update_layer_context_change_config(AV1_COMP *const cpi,
	const int64_t target_bandwidth) {
	const RATE_CONTROL *const rc = &cpi->rc;
	const PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;
	SVC *const svc = &cpi->svc;
	int layer = 0;
	int64_t spatial_layer_target = 0;
	float bitrate_alloc = 1.0;
	for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
	for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
	layer = LAYER_IDS_TO_IDX(sl, tl, svc->number_temporal_layers);
	LAYER_CONTEXT *const lc = &svc->layer_context[layer];
	svc->layer_context[layer].target_bandwidth = lc->layer_target_bitrate;
	}
	spatial_layer_target = svc->layer_context[layer].target_bandwidth;
	for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
	LAYER_CONTEXT *const lc =
	&svc->layer_context[sl * svc->number_temporal_layers + tl];
	RATE_CONTROL *const lrc = &lc->rc;
	PRIMARY_RATE_CONTROL *const lp_rc = &lc->p_rc;
	lc->spatial_layer_target_bandwidth = spatial_layer_target;
	bitrate_alloc = (float)lc->target_bandwidth / target_bandwidth;
	lp_rc->starting_buffer_level =
	(int64_t)(p_rc->starting_buffer_level * bitrate_alloc);
	lp_rc->optimal_buffer_level =
	(int64_t)(p_rc->optimal_buffer_level * bitrate_alloc);
	lp_rc->maximum_buffer_size =
	(int64_t)(p_rc->maximum_buffer_size * bitrate_alloc);
	lp_rc->bits_off_target =
	AOMMIN(lp_rc->bits_off_target, lp_rc->maximum_buffer_size);
	lp_rc->buffer_level =
	AOMMIN(lp_rc->buffer_level, lp_rc->maximum_buffer_size);
	lc->framerate = cpi->framerate / lc->framerate_factor;
	lrc->avg_frame_bandwidth =
	(int)round(lc->target_bandwidth / lc->framerate);
	lrc->max_frame_bandwidth = rc->max_frame_bandwidth;
	lrc->rtc_external_ratectrl = rc->rtc_external_ratectrl;
	lrc->worst_quality = av1_quantizer_to_qindex(lc->max_q);
	lrc->best_quality = av1_quantizer_to_qindex(lc->min_q);
	}
	}
	}

	/*!\brief Return layer context for current layer.
	*
	* \ingroup rate_control
	* \param[in] cpi Top level encoder structure
	*
	* \return LAYER_CONTEXT for current layer.
	*/
	static LAYER_CONTEXT get_layer_context(AV1_COMP const cpi) {
	return &cpi->svc.layer_context[cpi->svc.spatial_layer_id *
	cpi->svc.number_temporal_layers +
	cpi->svc.temporal_layer_id];
	}

	void av1_update_temporal_layer_framerate(AV1_COMP *const cpi) {
	SVC *const svc = &cpi->svc;
	LAYER_CONTEXT *const lc = get_layer_context(cpi);
	RATE_CONTROL *const lrc = &lc->rc;
	const int tl = svc->temporal_layer_id;
	lc->framerate = cpi->framerate / lc->framerate_factor;
	lrc->avg_frame_bandwidth = (int)round(lc->target_bandwidth / lc->framerate);
	lrc->max_frame_bandwidth = cpi->rc.max_frame_bandwidth;
	// Update the average layer frame size (non-cumulative per-frame-bw).
	if (tl == 0) {
	lc->avg_frame_size = lrc->avg_frame_bandwidth;
	} else {
	int prev_layer = svc->spatial_layer_id * svc->number_temporal_layers +
	svc->temporal_layer_id - 1;
	LAYER_CONTEXT *const lcprev = &svc->layer_context[prev_layer];
	const double prev_layer_framerate =
	cpi->framerate / lcprev->framerate_factor;
	const int64_t prev_layer_target_bandwidth = lcprev->layer_target_bitrate;
	lc->avg_frame_size =
	(int)round((lc->target_bandwidth - prev_layer_target_bandwidth) /
	(lc->framerate - prev_layer_framerate));
	}
	}

	void av1_restore_layer_context(AV1_COMP *const cpi) {
	SVC *const svc = &cpi->svc;
	const AV1_COMMON *const cm = &cpi->common;
	LAYER_CONTEXT *const lc = get_layer_context(cpi);
	const int old_frame_since_key = cpi->rc.frames_since_key;
	const int old_frame_to_key = cpi->rc.frames_to_key;
	// Restore layer rate control.
	cpi->rc = lc->rc;
	cpi->ppi->p_rc = lc->p_rc;
	cpi->oxcf.rc_cfg.target_bandwidth = lc->target_bandwidth;
	cpi->gf_frame_index = 0;
	cpi->mv_search_params.max_mv_magnitude = lc->max_mv_magnitude;
	if (cpi->mv_search_params.max_mv_magnitude == 0)
	cpi->mv_search_params.max_mv_magnitude = AOMMAX(cm->width, cm->height);
	// Reset the frames_since_key and frames_to_key counters to their values
	// before the layer restore. Keep these defined for the stream (not layer).
	cpi->rc.frames_since_key = old_frame_since_key;
	cpi->rc.frames_to_key = old_frame_to_key;
	// For spatial-svc, allow cyclic-refresh to be applied on the spatial layers,
	// for the base temporal layer.
	if (cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ &&
	svc->number_spatial_layers > 1 && svc->temporal_layer_id == 0) {
	CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
	swap_ptr(&cr->map, &lc->map);
	cr->sb_index = lc->sb_index;
	cr->actual_num_seg1_blocks = lc->actual_num_seg1_blocks;
	cr->actual_num_seg2_blocks = lc->actual_num_seg2_blocks;
	}
	svc->skip_mvsearch_last = 0;
	svc->skip_mvsearch_gf = 0;
	// For each reference (LAST/GOLDEN) set the skip_mvsearch_last/gf frame flags.
	// This is to skip searching mv for that reference if it was last
	// refreshed (i.e., buffer slot holding that reference was refreshed) on the
	// previous spatial layer(s) at the same time (current_superframe).
	if (svc->set_ref_frame_config && svc->force_zero_mode_spatial_ref) {
	int ref_frame_idx = svc->ref_idx[LAST_FRAME - 1];
	if (svc->buffer_time_index[ref_frame_idx] == svc->current_superframe &&
	svc->buffer_spatial_layer[ref_frame_idx] <= svc->spatial_layer_id - 1)
	svc->skip_mvsearch_last = 1;
	ref_frame_idx = svc->ref_idx[GOLDEN_FRAME - 1];
	if (svc->buffer_time_index[ref_frame_idx] == svc->current_superframe &&
	svc->buffer_spatial_layer[ref_frame_idx] <= svc->spatial_layer_id - 1)
	svc->skip_mvsearch_gf = 1;
	}
	}

	void av1_save_layer_context(AV1_COMP *const cpi) {
	SVC *const svc = &cpi->svc;
	const AV1_COMMON *const cm = &cpi->common;
	LAYER_CONTEXT *lc = get_layer_context(cpi);
	lc->rc = cpi->rc;
	lc->p_rc = cpi->ppi->p_rc;
	lc->target_bandwidth = (int)cpi->oxcf.rc_cfg.target_bandwidth;
	lc->group_index = cpi->gf_frame_index;
	lc->max_mv_magnitude = cpi->mv_search_params.max_mv_magnitude;
	if (svc->spatial_layer_id == 0) svc->base_framerate = cpi->framerate;
	// For spatial-svc, allow cyclic-refresh to be applied on the spatial layers,
	// for the base temporal layer.
	if (cpi->oxcf.q_cfg.aq_mode == CYCLIC_REFRESH_AQ &&
	cpi->svc.number_spatial_layers > 1 && svc->temporal_layer_id == 0) {
	CYCLIC_REFRESH *const cr = cpi->cyclic_refresh;
	signed char *temp = lc->map;
	lc->map = cr->map;
	cr->map = temp;
	lc->sb_index = cr->sb_index;
	lc->actual_num_seg1_blocks = cr->actual_num_seg1_blocks;
	lc->actual_num_seg2_blocks = cr->actual_num_seg2_blocks;
	}
	// For any buffer slot that is refreshed, update it with
	// the spatial_layer_id and the current_superframe.
	if (cpi->common.current_frame.frame_type == KEY_FRAME) {
	// All slots are refreshed on KEY.
	for (unsigned int i = 0; i < REF_FRAMES; i++) {
	svc->buffer_time_index[i] = svc->current_superframe;
	svc->buffer_spatial_layer[i] = svc->spatial_layer_id;
	}
	} else if (cpi->svc.set_ref_frame_config) {
	for (unsigned int i = 0; i < INTER_REFS_PER_FRAME; i++) {
	int ref_frame_map_idx = svc->ref_idx[i];
	if (cpi->svc.refresh[ref_frame_map_idx]) {
	svc->buffer_time_index[ref_frame_map_idx] = svc->current_superframe;
	svc->buffer_spatial_layer[ref_frame_map_idx] = svc->spatial_layer_id;
	}
	}
	}
	for (unsigned int i = 0; i < REF_FRAMES; i++) {
	if (frame_is_intra_only(cm) \|\|
	cm->current_frame.refresh_frame_flags & (1 << i)) {
	svc->spatial_layer_fb[i] = svc->spatial_layer_id;
	svc->temporal_layer_fb[i] = svc->temporal_layer_id;
	}
	}
	if (svc->spatial_layer_id == svc->number_spatial_layers - 1)
	svc->current_superframe++;
	}

	int av1_svc_primary_ref_frame(const AV1_COMP *const cpi) {
	const SVC *const svc = &cpi->svc;
	const AV1_COMMON *const cm = &cpi->common;
	int fb_idx = -1;
	int primary_ref_frame = PRIMARY_REF_NONE;
	// Set the primary_ref_frame to LAST_FRAME if that buffer slot for LAST
	// was last updated on a lower temporal layer (or base TL0) and for the
	// same spatial layer. For RTC patterns this allows for continued decoding
	// when set of enhancement layers are dropped (continued decoding starting
	// at next base TL0), so error_resilience can be off/0 for all layers.
	fb_idx = get_ref_frame_map_idx(cm, LAST_FRAME);
	if (svc->spatial_layer_fb[fb_idx] == svc->spatial_layer_id &&
	(svc->temporal_layer_fb[fb_idx] < svc->temporal_layer_id \|\|
	svc->temporal_layer_fb[fb_idx] == 0)) {
	primary_ref_frame = 0; // LAST_FRAME
	}
	return primary_ref_frame;
	}

	void av1_free_svc_cyclic_refresh(AV1_COMP *const cpi) {
	SVC *const svc = &cpi->svc;
	for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
	for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
	int layer = LAYER_IDS_TO_IDX(sl, tl, svc->number_temporal_layers);
	LAYER_CONTEXT *const lc = &svc->layer_context[layer];
	if (lc->map) aom_free(lc->map);
	}
	}
	}

	void av1_svc_reset_temporal_layers(AV1_COMP *const cpi, int is_key) {
	SVC *const svc = &cpi->svc;
	LAYER_CONTEXT *lc = NULL;
	for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
	for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
	lc = &cpi->svc.layer_context[sl * svc->number_temporal_layers + tl];
	if (is_key) lc->frames_from_key_frame = 0;
	}
	}
	av1_update_temporal_layer_framerate(cpi);
	av1_restore_layer_context(cpi);
	}

	void av1_get_layer_resolution(const int width_org, const int height_org,
	const int num, const int den, int *width_out,
	int *height_out) {
	int w, h;
	if (width_out == NULL \|\| height_out == NULL \|\| den == 0) return;
	w = width_org * num / den;
	h = height_org * num / den;
	// Make height and width even.
	w += w % 2;
	h += h % 2;
	*width_out = w;
	*height_out = h;
	}

	void av1_one_pass_cbr_svc_start_layer(AV1_COMP *const cpi) {
	SVC *const svc = &cpi->svc;
	LAYER_CONTEXT *lc = NULL;
	int width = 0, height = 0;
	lc = &svc->layer_context[svc->spatial_layer_id * svc->number_temporal_layers +
	svc->temporal_layer_id];
	av1_get_layer_resolution(cpi->oxcf.frm_dim_cfg.width,
	cpi->oxcf.frm_dim_cfg.height, lc->scaling_factor_num,
	lc->scaling_factor_den, &width, &height);
	// Use Eightap_smooth for low resolutions.
	if (width * height <= 320 * 240)
	svc->downsample_filter_type[svc->spatial_layer_id] = EIGHTTAP_SMOOTH;

	cpi->common.width = width;
	cpi->common.height = height;
	alloc_mb_mode_info_buffers(cpi);
	av1_update_frame_size(cpi);
	if (svc->spatial_layer_id == 0) svc->high_source_sad_superframe = 0;
	}

	enum {
	SVC_LAST_FRAME = 0,
	SVC_LAST2_FRAME,
	SVC_LAST3_FRAME,
	SVC_GOLDEN_FRAME,
	SVC_BWDREF_FRAME,
	SVC_ALTREF2_FRAME,
	SVC_ALTREF_FRAME
	};

	// For fixed svc mode: fixed pattern is set based on the number of
	// spatial and temporal layers, and the ksvc_fixed_mode.
	void av1_set_svc_fixed_mode(AV1_COMP *const cpi) {
	SVC *const svc = &cpi->svc;
	int i;
	assert(svc->use_flexible_mode == 0);
	// Fixed SVC mode only supports at most 3 spatial or temporal layers.
	assert(svc->number_spatial_layers >= 1 && svc->number_spatial_layers <= 3 &&
	svc->number_temporal_layers >= 1 && svc->number_temporal_layers <= 3);
	svc->set_ref_frame_config = 1;
	int superframe_cnt = svc->current_superframe;
	// Set the reference map buffer idx for the 7 references:
	// LAST_FRAME (0), LAST2_FRAME(1), LAST3_FRAME(2), GOLDEN_FRAME(3),
	// BWDREF_FRAME(4), ALTREF2_FRAME(5), ALTREF_FRAME(6).
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = i;
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->reference[i] = 0;
	for (i = 0; i < REF_FRAMES; i++) svc->refresh[i] = 0;
	// Always reference LAST, and reference GOLDEN on SL > 0.
	// For KSVC: GOLDEN reference will be removed on INTER_FRAMES later
	// when frame_type is set.
	svc->reference[SVC_LAST_FRAME] = 1;
	if (svc->spatial_layer_id > 0) svc->reference[SVC_GOLDEN_FRAME] = 1;
	if (svc->temporal_layer_id == 0) {
	// Base temporal layer.
	if (svc->spatial_layer_id == 0) {
	// Set all buffer_idx to 0. Update slot 0 (LAST).
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
	svc->refresh[0] = 1;
	} else if (svc->spatial_layer_id == 1) {
	// Set buffer_idx for LAST to slot 1, GOLDEN (and all other refs) to
	// slot 0. Update slot 1 (LAST).
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
	svc->ref_idx[SVC_LAST_FRAME] = 1;
	svc->refresh[1] = 1;
	} else if (svc->spatial_layer_id == 2) {
	// Set buffer_idx for LAST to slot 2, GOLDEN (and all other refs) to
	// slot 1. Update slot 2 (LAST).
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 1;
	svc->ref_idx[SVC_LAST_FRAME] = 2;
	svc->refresh[2] = 1;
	}
	} else if (svc->temporal_layer_id == 2 && (superframe_cnt - 1) % 4 == 0) {
	// First top temporal enhancement layer.
	if (svc->spatial_layer_id == 0) {
	// Reference LAST (slot 0).
	// Set GOLDEN to slot 3 and update slot 3.
	// Set all other buffer_idx to slot 0.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
	if (svc->spatial_layer_id < svc->number_spatial_layers - 1) {
	svc->ref_idx[SVC_GOLDEN_FRAME] = 3;
	svc->refresh[3] = 1;
	}
	} else if (svc->spatial_layer_id == 1) {
	// Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 1,
	// GOLDEN (and all other refs) to slot 3.
	// Set LAST2 to slot 4 and Update slot 4.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 3;
	svc->ref_idx[SVC_LAST_FRAME] = 1;
	if (svc->spatial_layer_id < svc->number_spatial_layers - 1) {
	svc->ref_idx[SVC_LAST2_FRAME] = 4;
	svc->refresh[4] = 1;
	}
	} else if (svc->spatial_layer_id == 2) {
	// Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 2,
	// GOLDEN (and all other refs) to slot 4.
	// No update.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 4;
	svc->ref_idx[SVC_LAST_FRAME] = 2;
	}
	} else if (svc->temporal_layer_id == 1) {
	// Middle temporal enhancement layer.
	if (svc->spatial_layer_id == 0) {
	// Reference LAST.
	// Set all buffer_idx to 0.
	// Set GOLDEN to slot 5 and update slot 5.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
	if (svc->temporal_layer_id < svc->number_temporal_layers - 1) {
	svc->ref_idx[SVC_GOLDEN_FRAME] = 5;
	svc->refresh[5] = 1;
	}
	} else if (svc->spatial_layer_id == 1) {
	// Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 1,
	// GOLDEN (and all other refs) to slot 5.
	// Set LAST3 to slot 6 and update slot 6.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 5;
	svc->ref_idx[SVC_LAST_FRAME] = 1;
	if (svc->temporal_layer_id < svc->number_temporal_layers - 1) {
	svc->ref_idx[SVC_LAST3_FRAME] = 6;
	svc->refresh[6] = 1;
	}
	} else if (svc->spatial_layer_id == 2) {
	// Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 2,
	// GOLDEN (and all other refs) to slot 6.
	// Set LAST3 to slot 7 and update slot 7.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 6;
	svc->ref_idx[SVC_LAST_FRAME] = 2;
	if (svc->temporal_layer_id < svc->number_temporal_layers - 1) {
	svc->ref_idx[SVC_LAST3_FRAME] = 7;
	svc->refresh[7] = 1;
	}
	}
	} else if (svc->temporal_layer_id == 2 && (superframe_cnt - 3) % 4 == 0) {
	// Second top temporal enhancement layer.
	if (svc->spatial_layer_id == 0) {
	// Set LAST to slot 5 and reference LAST.
	// Set GOLDEN to slot 3 and update slot 3.
	// Set all other buffer_idx to 0.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
	svc->ref_idx[SVC_LAST_FRAME] = 5;
	if (svc->spatial_layer_id < svc->number_spatial_layers - 1) {
	svc->ref_idx[SVC_GOLDEN_FRAME] = 3;
	svc->refresh[3] = 1;
	}
	} else if (svc->spatial_layer_id == 1) {
	// Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 6,
	// GOLDEN to slot 3. Set LAST2 to slot 4 and update slot 4.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
	svc->ref_idx[SVC_LAST_FRAME] = 6;
	svc->ref_idx[SVC_GOLDEN_FRAME] = 3;
	if (svc->spatial_layer_id < svc->number_spatial_layers - 1) {
	svc->ref_idx[SVC_LAST2_FRAME] = 4;
	svc->refresh[4] = 1;
	}
	} else if (svc->spatial_layer_id == 2) {
	// Reference LAST and GOLDEN. Set buffer_idx for LAST to slot 7,
	// GOLDEN to slot 4. No update.
	for (i = 0; i < INTER_REFS_PER_FRAME; i++) svc->ref_idx[i] = 0;
	svc->ref_idx[SVC_LAST_FRAME] = 7;
	svc->ref_idx[SVC_GOLDEN_FRAME] = 4;
	}
	}
	}

	void av1_svc_check_reset_layer_rc_flag(AV1_COMP *const cpi) {
	SVC *const svc = &cpi->svc;
	for (int sl = 0; sl < svc->number_spatial_layers; ++sl) {
	// Check for reset based on avg_frame_bandwidth for spatial layer sl.
	int layer = LAYER_IDS_TO_IDX(sl, svc->number_temporal_layers - 1,
	svc->number_temporal_layers);
	LAYER_CONTEXT *lc = &svc->layer_context[layer];
	RATE_CONTROL *lrc = &lc->rc;
	if (lrc->avg_frame_bandwidth > (3 * lrc->prev_avg_frame_bandwidth >> 1) \|\|
	lrc->avg_frame_bandwidth < (lrc->prev_avg_frame_bandwidth >> 1)) {
	// Reset for all temporal layers with spatial layer sl.
	for (int tl = 0; tl < svc->number_temporal_layers; ++tl) {
	int layer2 = LAYER_IDS_TO_IDX(sl, tl, svc->number_temporal_layers);
	LAYER_CONTEXT *lc2 = &svc->layer_context[layer2];
	RATE_CONTROL *lrc2 = &lc2->rc;
	PRIMARY_RATE_CONTROL *lp_rc2 = &lc2->p_rc;
	PRIMARY_RATE_CONTROL *const lp_rc = &lc2->p_rc;
	lrc2->rc_1_frame = 0;
	lrc2->rc_2_frame = 0;
	lp_rc2->bits_off_target = lp_rc->optimal_buffer_level;
	lp_rc2->buffer_level = lp_rc->optimal_buffer_level;
	}
	}
	}
	}