tor-browser

encode_strategy.c (68452B)

---

/*
* Copyright (c) 2019, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/

#include <stdint.h>

#include "av1/common/blockd.h"
#include "config/aom_config.h"
#include "config/aom_scale_rtcd.h"

#include "aom/aom_codec.h"
#include "aom/aom_encoder.h"

#if CONFIG_MISMATCH_DEBUG
#include "aom_util/debug_util.h"
#endif  // CONFIG_MISMATCH_DEBUG

#include "av1/common/av1_common_int.h"
#include "av1/common/reconinter.h"

#include "av1/encoder/encoder.h"
#include "av1/encoder/encode_strategy.h"
#include "av1/encoder/encodeframe.h"
#include "av1/encoder/encoder_alloc.h"
#include "av1/encoder/firstpass.h"
#include "av1/encoder/gop_structure.h"
#include "av1/encoder/pass2_strategy.h"
#include "av1/encoder/temporal_filter.h"
#if CONFIG_THREE_PASS
#include "av1/encoder/thirdpass.h"
#endif  // CONFIG_THREE_PASS
#include "av1/encoder/tpl_model.h"

#if CONFIG_TUNE_VMAF
#include "av1/encoder/tune_vmaf.h"
#endif

#define TEMPORAL_FILTER_KEY_FRAME (CONFIG_REALTIME_ONLY ? 0 : 1)

static inline void set_refresh_frame_flags(
   RefreshFrameInfo *const refresh_frame, bool refresh_gf, bool refresh_bwdref,
   bool refresh_arf) {
 refresh_frame->golden_frame = refresh_gf;
 refresh_frame->bwd_ref_frame = refresh_bwdref;
 refresh_frame->alt_ref_frame = refresh_arf;
}

void av1_configure_buffer_updates(AV1_COMP *const cpi,
                                 RefreshFrameInfo *const refresh_frame,
                                 const FRAME_UPDATE_TYPE type,
                                 const REFBUF_STATE refbuf_state,
                                 int force_refresh_all) {
 // NOTE(weitinglin): Should we define another function to take care of
 // cpi->rc.is_$Source_Type to make this function as it is in the comment?
 const ExtRefreshFrameFlagsInfo *const ext_refresh_frame_flags =
     &cpi->ext_flags.refresh_frame;
 cpi->rc.is_src_frame_alt_ref = 0;

 switch (type) {
   case KF_UPDATE:
     set_refresh_frame_flags(refresh_frame, true, true, true);
     break;

   case LF_UPDATE:
     set_refresh_frame_flags(refresh_frame, false, false, false);
     break;

   case GF_UPDATE:
     set_refresh_frame_flags(refresh_frame, true, false, false);
     break;

   case OVERLAY_UPDATE:
     if (refbuf_state == REFBUF_RESET)
       set_refresh_frame_flags(refresh_frame, true, true, true);
     else
       set_refresh_frame_flags(refresh_frame, true, false, false);

     cpi->rc.is_src_frame_alt_ref = 1;
     break;

   case ARF_UPDATE:
     // NOTE: BWDREF does not get updated along with ALTREF_FRAME.
     if (refbuf_state == REFBUF_RESET)
       set_refresh_frame_flags(refresh_frame, true, true, true);
     else
       set_refresh_frame_flags(refresh_frame, false, false, true);

     break;

   case INTNL_OVERLAY_UPDATE:
     set_refresh_frame_flags(refresh_frame, false, false, false);
     cpi->rc.is_src_frame_alt_ref = 1;
     break;

   case INTNL_ARF_UPDATE:
     set_refresh_frame_flags(refresh_frame, false, true, false);
     break;

   default: assert(0); break;
 }

 if (ext_refresh_frame_flags->update_pending &&
     (!is_stat_generation_stage(cpi))) {
   set_refresh_frame_flags(refresh_frame,
                           ext_refresh_frame_flags->golden_frame,
                           ext_refresh_frame_flags->bwd_ref_frame,
                           ext_refresh_frame_flags->alt_ref_frame);
   GF_GROUP *gf_group = &cpi->ppi->gf_group;
   if (ext_refresh_frame_flags->golden_frame)
     gf_group->update_type[cpi->gf_frame_index] = GF_UPDATE;
   if (ext_refresh_frame_flags->alt_ref_frame)
     gf_group->update_type[cpi->gf_frame_index] = ARF_UPDATE;
   if (ext_refresh_frame_flags->bwd_ref_frame)
     gf_group->update_type[cpi->gf_frame_index] = INTNL_ARF_UPDATE;
 }

 if (force_refresh_all)
   set_refresh_frame_flags(refresh_frame, true, true, true);
}

static void set_additional_frame_flags(const AV1_COMMON *const cm,
                                      unsigned int *const frame_flags) {
 if (frame_is_intra_only(cm)) {
   *frame_flags |= FRAMEFLAGS_INTRAONLY;
 }
 if (frame_is_sframe(cm)) {
   *frame_flags |= FRAMEFLAGS_SWITCH;
 }
 if (cm->features.error_resilient_mode) {
   *frame_flags |= FRAMEFLAGS_ERROR_RESILIENT;
 }
}

static void set_ext_overrides(AV1_COMMON *const cm,
                             EncodeFrameParams *const frame_params,
                             ExternalFlags *const ext_flags) {
 // Overrides the defaults with the externally supplied values with
 // av1_update_reference() and av1_update_entropy() calls
 // Note: The overrides are valid only for the next frame passed
 // to av1_encode_lowlevel()

 if (ext_flags->use_s_frame) {
   frame_params->frame_type = S_FRAME;
 }

 if (ext_flags->refresh_frame_context_pending) {
   cm->features.refresh_frame_context = ext_flags->refresh_frame_context;
   ext_flags->refresh_frame_context_pending = 0;
 }
 cm->features.allow_ref_frame_mvs = ext_flags->use_ref_frame_mvs;

 frame_params->error_resilient_mode = ext_flags->use_error_resilient;
 // A keyframe is already error resilient and keyframes with
 // error_resilient_mode interferes with the use of show_existing_frame
 // when forward reference keyframes are enabled.
 frame_params->error_resilient_mode &= frame_params->frame_type != KEY_FRAME;
 // For bitstream conformance, s-frames must be error-resilient
 frame_params->error_resilient_mode |= frame_params->frame_type == S_FRAME;
}

static int choose_primary_ref_frame(
   AV1_COMP *const cpi, const EncodeFrameParams *const frame_params) {
 const AV1_COMMON *const cm = &cpi->common;

 const int intra_only = frame_params->frame_type == KEY_FRAME ||
                        frame_params->frame_type == INTRA_ONLY_FRAME;
 if (intra_only || frame_params->error_resilient_mode ||
     cpi->ext_flags.use_primary_ref_none) {
   return PRIMARY_REF_NONE;
 }

#if !CONFIG_REALTIME_ONLY
 if (cpi->use_ducky_encode) {
   int wanted_fb = cpi->ppi->gf_group.primary_ref_idx[cpi->gf_frame_index];
   for (int ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ref_frame++) {
     if (get_ref_frame_map_idx(cm, ref_frame) == wanted_fb)
       return ref_frame - LAST_FRAME;
   }

   return PRIMARY_REF_NONE;
 }
#endif  // !CONFIG_REALTIME_ONLY

 // In large scale case, always use Last frame's frame contexts.
 // Note(yunqing): In other cases, primary_ref_frame is chosen based on
 // cpi->ppi->gf_group.layer_depth[cpi->gf_frame_index], which also controls
 // frame bit allocation.
 if (cm->tiles.large_scale) return (LAST_FRAME - LAST_FRAME);

 if (cpi->ppi->use_svc || cpi->ppi->rtc_ref.set_ref_frame_config)
   return av1_svc_primary_ref_frame(cpi);

 // Find the most recent reference frame with the same reference type as the
 // current frame
 const int current_ref_type = get_current_frame_ref_type(cpi);
 int wanted_fb = cpi->ppi->fb_of_context_type[current_ref_type];
#if CONFIG_FPMT_TEST
 if (cpi->ppi->fpmt_unit_test_cfg == PARALLEL_SIMULATION_ENCODE) {
   GF_GROUP *const gf_group = &cpi->ppi->gf_group;
   if (gf_group->update_type[cpi->gf_frame_index] == INTNL_ARF_UPDATE) {
     int frame_level = gf_group->frame_parallel_level[cpi->gf_frame_index];
     // Book keep wanted_fb of frame_parallel_level 1 frame in an FP2 set.
     if (frame_level == 1) {
       cpi->wanted_fb = wanted_fb;
     }
     // Use the wanted_fb of level 1 frame in an FP2 for a level 2 frame in the
     // set.
     if (frame_level == 2 &&
         gf_group->update_type[cpi->gf_frame_index - 1] == INTNL_ARF_UPDATE) {
       assert(gf_group->frame_parallel_level[cpi->gf_frame_index - 1] == 1);
       wanted_fb = cpi->wanted_fb;
     }
   }
 }
#endif  // CONFIG_FPMT_TEST
 int primary_ref_frame = PRIMARY_REF_NONE;
 for (int ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ref_frame++) {
   if (get_ref_frame_map_idx(cm, ref_frame) == wanted_fb) {
     primary_ref_frame = ref_frame - LAST_FRAME;
   }
 }

 return primary_ref_frame;
}

static void adjust_frame_rate(AV1_COMP *cpi, int64_t ts_start, int64_t ts_end) {
 TimeStamps *time_stamps = &cpi->time_stamps;
 int64_t this_duration;
 int step = 0;

 // Clear down mmx registers

 if (is_one_pass_rt_params(cpi) ||
     (cpi->ppi->use_svc && cpi->ppi->rtc_ref.set_ref_frame_config &&
      cpi->svc.number_spatial_layers > 1)) {
   // ts_start is the timestamp for the current frame and ts_end is the
   // expected next timestamp given the duration passed into codec_encode().
   // See the setting in encoder_encode() in av1_cx_iface.c:
   // ts_start = timebase_units_to_ticks(cpi_data.timestamp_ratio, ptsvol),
   // ts_end = timebase_units_to_ticks(cpi_data.timestamp_ratio, ptsvol +
   // duration). So the difference ts_end - ts_start is the duration passed
   // in by the user. For RTC or spatial layers SVC set the framerate based
   // directly on the duration, and bypass the adjustments below.
   this_duration = ts_end - ts_start;
   if (this_duration > 0) {
     cpi->new_framerate = 10000000.0 / this_duration;
     av1_new_framerate(cpi, cpi->new_framerate);
     time_stamps->prev_ts_start = ts_start;
     time_stamps->prev_ts_end = ts_end;
     return;
   }
 }

 if (ts_start == time_stamps->first_ts_start) {
   this_duration = ts_end - ts_start;
   step = 1;
 } else {
   int64_t last_duration =
       time_stamps->prev_ts_end - time_stamps->prev_ts_start;

   this_duration = ts_end - time_stamps->prev_ts_end;

   // do a step update if the duration changes by 10%
   if (last_duration)
     step = (int)((this_duration - last_duration) * 10 / last_duration);
 }

 if (this_duration) {
   if (step) {
     cpi->new_framerate = 10000000.0 / this_duration;
     av1_new_framerate(cpi, cpi->new_framerate);
   } else {
     // Average this frame's rate into the last second's average
     // frame rate. If we haven't seen 1 second yet, then average
     // over the whole interval seen.
     const double interval =
         AOMMIN((double)(ts_end - time_stamps->first_ts_start), 10000000.0);
     double avg_duration = 10000000.0 / cpi->framerate;
     avg_duration *= (interval - avg_duration + this_duration);
     avg_duration /= interval;
     cpi->new_framerate = (10000000.0 / avg_duration);
     // For parallel frames update cpi->framerate with new_framerate
     // during av1_post_encode_updates()
     double framerate =
         (cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0)
             ? cpi->framerate
             : cpi->new_framerate;
     av1_new_framerate(cpi, framerate);
   }
 }

 time_stamps->prev_ts_start = ts_start;
 time_stamps->prev_ts_end = ts_end;
}

// Determine whether there is a forced keyframe pending in the lookahead buffer
int is_forced_keyframe_pending(struct lookahead_ctx *lookahead,
                              const int up_to_index,
                              const COMPRESSOR_STAGE compressor_stage) {
 for (int i = 0; i <= up_to_index; i++) {
   const struct lookahead_entry *e =
       av1_lookahead_peek(lookahead, i, compressor_stage);
   if (e == NULL) {
     // We have reached the end of the lookahead buffer and not early-returned
     // so there isn't a forced key-frame pending.
     return -1;
   } else if (e->flags == AOM_EFLAG_FORCE_KF) {
     return i;
   } else {
     continue;
   }
 }
 return -1;  // Never reached
}

// Check if we should encode an ARF or internal ARF.  If not, try a LAST
// Do some setup associated with the chosen source
// temporal_filtered, flush, and frame_update_type are outputs.
// Return the frame source, or NULL if we couldn't find one
static struct lookahead_entry *choose_frame_source(
   AV1_COMP *const cpi, int *const flush, int *pop_lookahead,
   struct lookahead_entry **last_source, int *const show_frame) {
 AV1_COMMON *const cm = &cpi->common;
 const GF_GROUP *const gf_group = &cpi->ppi->gf_group;
 struct lookahead_entry *source = NULL;

 // Source index in lookahead buffer.
 int src_index = gf_group->arf_src_offset[cpi->gf_frame_index];

 // TODO(Aasaipriya): Forced key frames need to be fixed when rc_mode != AOM_Q
 if (src_index &&
     (is_forced_keyframe_pending(cpi->ppi->lookahead, src_index,
                                 cpi->compressor_stage) != -1) &&
     cpi->oxcf.rc_cfg.mode != AOM_Q && !is_stat_generation_stage(cpi)) {
   src_index = 0;
   *flush = 1;
 }

 // If the current frame is arf, then we should not pop from the lookahead
 // buffer. If the current frame is not arf, then pop it. This assumes the
 // first frame in the GF group is not arf. May need to change if it is not
 // true.
 *pop_lookahead = (src_index == 0);
 // If this is a key frame and keyframe filtering is enabled with overlay,
 // then do not pop.
 if (*pop_lookahead && cpi->oxcf.kf_cfg.enable_keyframe_filtering > 1 &&
     gf_group->update_type[cpi->gf_frame_index] == ARF_UPDATE &&
     !is_stat_generation_stage(cpi) && cpi->ppi->lookahead) {
   if (cpi->ppi->lookahead->read_ctxs[cpi->compressor_stage].sz &&
       (*flush ||
        cpi->ppi->lookahead->read_ctxs[cpi->compressor_stage].sz ==
            cpi->ppi->lookahead->read_ctxs[cpi->compressor_stage].pop_sz)) {
     *pop_lookahead = 0;
   }
 }

 // LAP stage does not have ARFs or forward key-frames,
 // hence, always pop_lookahead here.
 if (is_stat_generation_stage(cpi)) {
   *pop_lookahead = 1;
   src_index = 0;
 }

 *show_frame = *pop_lookahead;

#if CONFIG_FPMT_TEST
 if (cpi->ppi->fpmt_unit_test_cfg == PARALLEL_ENCODE) {
#else
 {
#endif  // CONFIG_FPMT_TEST
   // Future frame in parallel encode set
   if (gf_group->src_offset[cpi->gf_frame_index] != 0 &&
       !is_stat_generation_stage(cpi))
     src_index = gf_group->src_offset[cpi->gf_frame_index];
 }
 if (*show_frame) {
   // show frame, pop from buffer
   // Get last frame source.
   if (cm->current_frame.frame_number > 0) {
     *last_source = av1_lookahead_peek(cpi->ppi->lookahead, src_index - 1,
                                       cpi->compressor_stage);
   }
   // Read in the source frame.
   source = av1_lookahead_peek(cpi->ppi->lookahead, src_index,
                               cpi->compressor_stage);
 } else {
   // no show frames are arf frames
   source = av1_lookahead_peek(cpi->ppi->lookahead, src_index,
                               cpi->compressor_stage);
   if (source != NULL) {
     cm->showable_frame = 1;
   }
 }
 return source;
}

// Don't allow a show_existing_frame to coincide with an error resilient or
// S-Frame. An exception can be made in the case of a keyframe, since it does
// not depend on any previous frames.
static int allow_show_existing(const AV1_COMP *const cpi,
                              unsigned int frame_flags) {
 if (cpi->common.current_frame.frame_number == 0) return 0;

 const struct lookahead_entry *lookahead_src =
     av1_lookahead_peek(cpi->ppi->lookahead, 0, cpi->compressor_stage);
 if (lookahead_src == NULL) return 1;

 const int is_error_resilient =
     cpi->oxcf.tool_cfg.error_resilient_mode ||
     (lookahead_src->flags & AOM_EFLAG_ERROR_RESILIENT);
 const int is_s_frame = cpi->oxcf.kf_cfg.enable_sframe ||
                        (lookahead_src->flags & AOM_EFLAG_SET_S_FRAME);
 const int is_key_frame =
     (cpi->rc.frames_to_key == 0) || (frame_flags & FRAMEFLAGS_KEY);
 return !(is_error_resilient || is_s_frame) || is_key_frame;
}

// Update frame_flags to tell the encoder's caller what sort of frame was
// encoded.
static void update_frame_flags(const AV1_COMMON *const cm,
                              const RefreshFrameInfo *const refresh_frame,
                              unsigned int *frame_flags) {
 if (encode_show_existing_frame(cm)) {
   *frame_flags &= ~(uint32_t)FRAMEFLAGS_GOLDEN;
   *frame_flags &= ~(uint32_t)FRAMEFLAGS_BWDREF;
   *frame_flags &= ~(uint32_t)FRAMEFLAGS_ALTREF;
   *frame_flags &= ~(uint32_t)FRAMEFLAGS_KEY;
   return;
 }

 if (refresh_frame->golden_frame) {
   *frame_flags |= FRAMEFLAGS_GOLDEN;
 } else {
   *frame_flags &= ~(uint32_t)FRAMEFLAGS_GOLDEN;
 }

 if (refresh_frame->alt_ref_frame) {
   *frame_flags |= FRAMEFLAGS_ALTREF;
 } else {
   *frame_flags &= ~(uint32_t)FRAMEFLAGS_ALTREF;
 }

 if (refresh_frame->bwd_ref_frame) {
   *frame_flags |= FRAMEFLAGS_BWDREF;
 } else {
   *frame_flags &= ~(uint32_t)FRAMEFLAGS_BWDREF;
 }

 if (cm->current_frame.frame_type == KEY_FRAME) {
   *frame_flags |= FRAMEFLAGS_KEY;
 } else {
   *frame_flags &= ~(uint32_t)FRAMEFLAGS_KEY;
 }
}

#define DUMP_REF_FRAME_IMAGES 0

#if DUMP_REF_FRAME_IMAGES == 1
static int dump_one_image(AV1_COMMON *cm,
                         const YV12_BUFFER_CONFIG *const ref_buf,
                         char *file_name) {
 int h;
 FILE *f_ref = NULL;

 if (ref_buf == NULL) {
   printf("Frame data buffer is NULL.\n");
   return AOM_CODEC_MEM_ERROR;
 }

 if ((f_ref = fopen(file_name, "wb")) == NULL) {
   printf("Unable to open file %s to write.\n", file_name);
   return AOM_CODEC_MEM_ERROR;
 }

 // --- Y ---
 for (h = 0; h < cm->height; ++h) {
   fwrite(&ref_buf->y_buffer[h * ref_buf->y_stride], 1, cm->width, f_ref);
 }
 // --- U ---
 for (h = 0; h < (cm->height >> 1); ++h) {
   fwrite(&ref_buf->u_buffer[h * ref_buf->uv_stride], 1, (cm->width >> 1),
          f_ref);
 }
 // --- V ---
 for (h = 0; h < (cm->height >> 1); ++h) {
   fwrite(&ref_buf->v_buffer[h * ref_buf->uv_stride], 1, (cm->width >> 1),
          f_ref);
 }

 fclose(f_ref);

 return AOM_CODEC_OK;
}

static void dump_ref_frame_images(AV1_COMP *cpi) {
 AV1_COMMON *const cm = &cpi->common;
 MV_REFERENCE_FRAME ref_frame;

 for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
   char file_name[256] = "";
   snprintf(file_name, sizeof(file_name), "/tmp/enc_F%d_ref_%d.yuv",
            cm->current_frame.frame_number, ref_frame);
   dump_one_image(cm, get_ref_frame_yv12_buf(cpi, ref_frame), file_name);
 }
}
#endif  // DUMP_REF_FRAME_IMAGES == 1

int av1_get_refresh_ref_frame_map(int refresh_frame_flags) {
 int ref_map_index;

 for (ref_map_index = 0; ref_map_index < REF_FRAMES; ++ref_map_index)
   if ((refresh_frame_flags >> ref_map_index) & 1) break;

 if (ref_map_index == REF_FRAMES) ref_map_index = INVALID_IDX;
 return ref_map_index;
}

static int get_free_ref_map_index(RefFrameMapPair ref_map_pairs[REF_FRAMES]) {
 for (int idx = 0; idx < REF_FRAMES; ++idx)
   if (ref_map_pairs[idx].disp_order == -1) return idx;
 return INVALID_IDX;
}

static int get_refresh_idx(RefFrameMapPair ref_frame_map_pairs[REF_FRAMES],
                          int update_arf, GF_GROUP *gf_group, int gf_index,
                          int enable_refresh_skip, int cur_frame_disp) {
 int arf_count = 0;
 int oldest_arf_order = INT32_MAX;
 int oldest_arf_idx = -1;

 int oldest_frame_order = INT32_MAX;
 int oldest_idx = -1;

 for (int map_idx = 0; map_idx < REF_FRAMES; map_idx++) {
   RefFrameMapPair ref_pair = ref_frame_map_pairs[map_idx];
   if (ref_pair.disp_order == -1) continue;
   const int frame_order = ref_pair.disp_order;
   const int reference_frame_level = ref_pair.pyr_level;
   // Keep future frames and three closest previous frames in output order.
   if (frame_order > cur_frame_disp - 3) continue;

   if (enable_refresh_skip) {
     int skip_frame = 0;
     // Prevent refreshing a frame in gf_group->skip_frame_refresh.
     for (int i = 0; i < REF_FRAMES; i++) {
       int frame_to_skip = gf_group->skip_frame_refresh[gf_index][i];
       if (frame_to_skip == INVALID_IDX) break;
       if (frame_order == frame_to_skip) {
         skip_frame = 1;
         break;
       }
     }
     if (skip_frame) continue;
   }

   // Keep track of the oldest level 1 frame if the current frame is also level
   // 1.
   if (reference_frame_level == 1) {
     // If there are more than 2 level 1 frames in the reference list,
     // discard the oldest.
     if (frame_order < oldest_arf_order) {
       oldest_arf_order = frame_order;
       oldest_arf_idx = map_idx;
     }
     arf_count++;
     continue;
   }

   // Update the overall oldest reference frame.
   if (frame_order < oldest_frame_order) {
     oldest_frame_order = frame_order;
     oldest_idx = map_idx;
   }
 }
 if (update_arf && arf_count > 2) return oldest_arf_idx;
 if (oldest_idx >= 0) return oldest_idx;
 if (oldest_arf_idx >= 0) return oldest_arf_idx;
 if (oldest_idx == -1) {
   assert(arf_count > 2 && enable_refresh_skip);
   return oldest_arf_idx;
 }
 assert(0 && "No valid refresh index found");
 return -1;
}

// Computes the reference refresh index for INTNL_ARF_UPDATE frame.
int av1_calc_refresh_idx_for_intnl_arf(
   AV1_COMP *cpi, RefFrameMapPair ref_frame_map_pairs[REF_FRAMES],
   int gf_index) {
 GF_GROUP *const gf_group = &cpi->ppi->gf_group;

 // Search for the open slot to store the current frame.
 int free_fb_index = get_free_ref_map_index(ref_frame_map_pairs);

 // Use a free slot if available.
 if (free_fb_index != INVALID_IDX) {
   return free_fb_index;
 } else {
   int enable_refresh_skip = !is_one_pass_rt_params(cpi);
   int refresh_idx =
       get_refresh_idx(ref_frame_map_pairs, 0, gf_group, gf_index,
                       enable_refresh_skip, gf_group->display_idx[gf_index]);
   return refresh_idx;
 }
}

int av1_get_refresh_frame_flags(
   const AV1_COMP *const cpi, const EncodeFrameParams *const frame_params,
   FRAME_UPDATE_TYPE frame_update_type, int gf_index, int cur_disp_order,
   RefFrameMapPair ref_frame_map_pairs[REF_FRAMES]) {
 const AV1_COMMON *const cm = &cpi->common;
 const ExtRefreshFrameFlagsInfo *const ext_refresh_frame_flags =
     &cpi->ext_flags.refresh_frame;

 GF_GROUP *gf_group = &cpi->ppi->gf_group;
 if (gf_group->refbuf_state[gf_index] == REFBUF_RESET)
   return SELECT_ALL_BUF_SLOTS;

 // TODO(jingning): Deprecate the following operations.
 // Switch frames and shown key-frames overwrite all reference slots
 if (frame_params->frame_type == S_FRAME) return SELECT_ALL_BUF_SLOTS;

 // show_existing_frames don't actually send refresh_frame_flags so set the
 // flags to 0 to keep things consistent.
 if (frame_params->show_existing_frame) return 0;

 const RTC_REF *const rtc_ref = &cpi->ppi->rtc_ref;
 if (is_frame_droppable(rtc_ref, ext_refresh_frame_flags)) return 0;

#if !CONFIG_REALTIME_ONLY
 if (cpi->use_ducky_encode &&
     cpi->ducky_encode_info.frame_info.gop_mode == DUCKY_ENCODE_GOP_MODE_RCL) {
   int new_fb_map_idx = cpi->ppi->gf_group.update_ref_idx[gf_index];
   if (new_fb_map_idx == INVALID_IDX) return 0;
   return 1 << new_fb_map_idx;
 }
#endif  // !CONFIG_REALTIME_ONLY

 int refresh_mask = 0;
 if (ext_refresh_frame_flags->update_pending) {
   if (rtc_ref->set_ref_frame_config ||
       use_rtc_reference_structure_one_layer(cpi)) {
     for (unsigned int i = 0; i < INTER_REFS_PER_FRAME; i++) {
       int ref_frame_map_idx = rtc_ref->ref_idx[i];
       refresh_mask |= rtc_ref->refresh[ref_frame_map_idx]
                       << ref_frame_map_idx;
     }
     return refresh_mask;
   }
   // Unfortunately the encoder interface reflects the old refresh_*_frame
   // flags so we have to replicate the old refresh_frame_flags logic here in
   // order to preserve the behaviour of the flag overrides.
   int ref_frame_map_idx = get_ref_frame_map_idx(cm, LAST_FRAME);
   if (ref_frame_map_idx != INVALID_IDX)
     refresh_mask |= ext_refresh_frame_flags->last_frame << ref_frame_map_idx;

   ref_frame_map_idx = get_ref_frame_map_idx(cm, EXTREF_FRAME);
   if (ref_frame_map_idx != INVALID_IDX)
     refresh_mask |= ext_refresh_frame_flags->bwd_ref_frame
                     << ref_frame_map_idx;

   ref_frame_map_idx = get_ref_frame_map_idx(cm, ALTREF2_FRAME);
   if (ref_frame_map_idx != INVALID_IDX)
     refresh_mask |= ext_refresh_frame_flags->alt2_ref_frame
                     << ref_frame_map_idx;

   if (frame_update_type == OVERLAY_UPDATE) {
     ref_frame_map_idx = get_ref_frame_map_idx(cm, ALTREF_FRAME);
     if (ref_frame_map_idx != INVALID_IDX)
       refresh_mask |= ext_refresh_frame_flags->golden_frame
                       << ref_frame_map_idx;
   } else {
     ref_frame_map_idx = get_ref_frame_map_idx(cm, GOLDEN_FRAME);
     if (ref_frame_map_idx != INVALID_IDX)
       refresh_mask |= ext_refresh_frame_flags->golden_frame
                       << ref_frame_map_idx;

     ref_frame_map_idx = get_ref_frame_map_idx(cm, ALTREF_FRAME);
     if (ref_frame_map_idx != INVALID_IDX)
       refresh_mask |= ext_refresh_frame_flags->alt_ref_frame
                       << ref_frame_map_idx;
   }
   return refresh_mask;
 }

 // Search for the open slot to store the current frame.
 int free_fb_index = get_free_ref_map_index(ref_frame_map_pairs);

 // No refresh necessary for these frame types.
 if (frame_update_type == OVERLAY_UPDATE ||
     frame_update_type == INTNL_OVERLAY_UPDATE)
   return refresh_mask;

 // If there is an open slot, refresh that one instead of replacing a
 // reference.
 if (free_fb_index != INVALID_IDX) {
   refresh_mask = 1 << free_fb_index;
   return refresh_mask;
 }
 const int enable_refresh_skip = !is_one_pass_rt_params(cpi);
 const int update_arf = frame_update_type == ARF_UPDATE;
 const int refresh_idx =
     get_refresh_idx(ref_frame_map_pairs, update_arf, &cpi->ppi->gf_group,
                     gf_index, enable_refresh_skip, cur_disp_order);
 return 1 << refresh_idx;
}

#if !CONFIG_REALTIME_ONLY
// Apply temporal filtering to source frames and encode the filtered frame.
// If the current frame does not require filtering, this function is identical
// to av1_encode() except that tpl is not performed.
static int denoise_and_encode(AV1_COMP *const cpi, uint8_t *const dest,
                             size_t dest_size,
                             EncodeFrameInput *const frame_input,
                             const EncodeFrameParams *const frame_params,
                             size_t *const frame_size) {
#if CONFIG_COLLECT_COMPONENT_TIMING
 if (cpi->oxcf.pass == 2) start_timing(cpi, denoise_and_encode_time);
#endif
 const AV1EncoderConfig *const oxcf = &cpi->oxcf;
 AV1_COMMON *const cm = &cpi->common;

 GF_GROUP *const gf_group = &cpi->ppi->gf_group;
 FRAME_UPDATE_TYPE update_type =
     get_frame_update_type(&cpi->ppi->gf_group, cpi->gf_frame_index);
 const int is_second_arf =
     av1_gop_is_second_arf(gf_group, cpi->gf_frame_index);

 // Decide whether to apply temporal filtering to the source frame.
 int apply_filtering =
     av1_is_temporal_filter_on(oxcf) && !is_stat_generation_stage(cpi);
 if (update_type != KF_UPDATE && update_type != ARF_UPDATE && !is_second_arf) {
   apply_filtering = 0;
 }
 if (apply_filtering) {
   if (frame_params->frame_type == KEY_FRAME) {
     // TODO(angiebird): Move the noise level check to av1_tf_info_filtering.
     // Decide whether it is allowed to perform key frame filtering
     int allow_kf_filtering = oxcf->kf_cfg.enable_keyframe_filtering &&
                              !frame_params->show_existing_frame &&
                              !is_lossless_requested(&oxcf->rc_cfg);
     if (allow_kf_filtering) {
       double y_noise_level = 0.0;
       av1_estimate_noise_level(
           frame_input->source, &y_noise_level, AOM_PLANE_Y, AOM_PLANE_Y,
           cm->seq_params->bit_depth, NOISE_ESTIMATION_EDGE_THRESHOLD);
       apply_filtering = y_noise_level > 0;
     } else {
       apply_filtering = 0;
     }
     // If we are doing kf filtering, set up a few things.
     if (apply_filtering) {
       av1_setup_past_independence(cm);
     }
   } else if (is_second_arf) {
     apply_filtering = cpi->sf.hl_sf.second_alt_ref_filtering;
   }
 }

#if CONFIG_COLLECT_COMPONENT_TIMING
 if (cpi->oxcf.pass == 2) start_timing(cpi, apply_filtering_time);
#endif
 // Save the pointer to the original source image.
 YV12_BUFFER_CONFIG *source_buffer = frame_input->source;
 // apply filtering to frame
 if (apply_filtering) {
   int show_existing_alt_ref = 0;
   FRAME_DIFF frame_diff;
   int top_index = 0;
   int bottom_index = 0;
   const int q_index = av1_rc_pick_q_and_bounds(
       cpi, cpi->oxcf.frm_dim_cfg.width, cpi->oxcf.frm_dim_cfg.height,
       cpi->gf_frame_index, &bottom_index, &top_index);

   // TODO(bohanli): figure out why we need frame_type in cm here.
   cm->current_frame.frame_type = frame_params->frame_type;
   if (update_type == KF_UPDATE || update_type == ARF_UPDATE) {
     YV12_BUFFER_CONFIG *tf_buf = av1_tf_info_get_filtered_buf(
         &cpi->ppi->tf_info, cpi->gf_frame_index, &frame_diff);
     if (tf_buf != NULL) {
       frame_input->source = tf_buf;
       show_existing_alt_ref = av1_check_show_filtered_frame(
           tf_buf, &frame_diff, q_index, cm->seq_params->bit_depth);
       if (show_existing_alt_ref) {
         cpi->common.showable_frame |= 1;
       } else {
         cpi->common.showable_frame = 0;
       }
     }
     if (gf_group->frame_type[cpi->gf_frame_index] != KEY_FRAME) {
       cpi->ppi->show_existing_alt_ref = show_existing_alt_ref;
     }
   }

   if (is_second_arf) {
     // Allocate the memory for tf_buf_second_arf buffer, only when it is
     // required.
     int ret = aom_realloc_frame_buffer(
         &cpi->ppi->tf_info.tf_buf_second_arf, oxcf->frm_dim_cfg.width,
         oxcf->frm_dim_cfg.height, cm->seq_params->subsampling_x,
         cm->seq_params->subsampling_y, cm->seq_params->use_highbitdepth,
         cpi->oxcf.border_in_pixels, cm->features.byte_alignment, NULL, NULL,
         NULL, cpi->alloc_pyramid, 0);
     if (ret)
       aom_internal_error(cm->error, AOM_CODEC_MEM_ERROR,
                          "Failed to allocate tf_buf_second_arf");

     YV12_BUFFER_CONFIG *tf_buf_second_arf =
         &cpi->ppi->tf_info.tf_buf_second_arf;
     // We didn't apply temporal filtering for second arf ahead in
     // av1_tf_info_filtering().
     const int arf_src_index = gf_group->arf_src_offset[cpi->gf_frame_index];
     // Right now, we are still using tf_buf_second_arf due to
     // implementation complexity.
     // TODO(angiebird): Reuse tf_info->tf_buf here.
     av1_temporal_filter(cpi, arf_src_index, cpi->gf_frame_index, &frame_diff,
                         tf_buf_second_arf);
     show_existing_alt_ref = av1_check_show_filtered_frame(
         tf_buf_second_arf, &frame_diff, q_index, cm->seq_params->bit_depth);
     if (show_existing_alt_ref) {
       aom_extend_frame_borders(tf_buf_second_arf, av1_num_planes(cm));
       frame_input->source = tf_buf_second_arf;
     }
     // Currently INTNL_ARF_UPDATE only do show_existing.
     cpi->common.showable_frame |= 1;
   }

   // Copy source metadata to the temporal filtered frame
   if (source_buffer->metadata &&
       aom_copy_metadata_to_frame_buffer(frame_input->source,
                                         source_buffer->metadata)) {
     aom_internal_error(
         cm->error, AOM_CODEC_MEM_ERROR,
         "Failed to copy source metadata to the temporal filtered frame");
   }
 }
#if CONFIG_COLLECT_COMPONENT_TIMING
 if (cpi->oxcf.pass == 2) end_timing(cpi, apply_filtering_time);
#endif

 int set_mv_params = frame_params->frame_type == KEY_FRAME ||
                     update_type == ARF_UPDATE || update_type == GF_UPDATE;
 cm->show_frame = frame_params->show_frame;
 cm->current_frame.frame_type = frame_params->frame_type;
 // TODO(bohanli): Why is this? what part of it is necessary?
 av1_set_frame_size(cpi, cm->width, cm->height);
 if (set_mv_params) av1_set_mv_search_params(cpi);

#if CONFIG_RD_COMMAND
 if (frame_params->frame_type == KEY_FRAME) {
   char filepath[] = "rd_command.txt";
   av1_read_rd_command(filepath, &cpi->rd_command);
 }
#endif  // CONFIG_RD_COMMAND
 if (cpi->gf_frame_index == 0 && !is_stat_generation_stage(cpi)) {
   // perform tpl after filtering
   int allow_tpl =
       oxcf->gf_cfg.lag_in_frames > 1 && oxcf->algo_cfg.enable_tpl_model;
   if (gf_group->size > MAX_LENGTH_TPL_FRAME_STATS) {
     allow_tpl = 0;
   }
   if (frame_params->frame_type != KEY_FRAME) {
     // In rare case, it's possible to have non ARF/GF update_type here.
     // We should set allow_tpl to zero in the situation
     allow_tpl =
         allow_tpl && (update_type == ARF_UPDATE || update_type == GF_UPDATE ||
                       (cpi->use_ducky_encode &&
                        cpi->ducky_encode_info.frame_info.gop_mode ==
                            DUCKY_ENCODE_GOP_MODE_RCL));
   }

   if (allow_tpl) {
     if (!cpi->skip_tpl_setup_stats) {
       av1_tpl_preload_rc_estimate(cpi, frame_params);
       av1_tpl_setup_stats(cpi, 0, frame_params);
#if CONFIG_BITRATE_ACCURACY && !CONFIG_THREE_PASS
       assert(cpi->gf_frame_index == 0);
       av1_vbr_rc_update_q_index_list(&cpi->vbr_rc_info, &cpi->ppi->tpl_data,
                                      gf_group, cm->seq_params->bit_depth);
#endif
     }
   } else {
     av1_init_tpl_stats(&cpi->ppi->tpl_data);
   }
#if CONFIG_BITRATE_ACCURACY && CONFIG_THREE_PASS
   if (cpi->oxcf.pass == AOM_RC_SECOND_PASS &&
       cpi->second_pass_log_stream != NULL) {
     TPL_INFO *tpl_info;
     AOM_CHECK_MEM_ERROR(cm->error, tpl_info, aom_malloc(sizeof(*tpl_info)));
     av1_pack_tpl_info(tpl_info, gf_group, &cpi->ppi->tpl_data);
     av1_write_tpl_info(tpl_info, cpi->second_pass_log_stream,
                        cpi->common.error);
     aom_free(tpl_info);
   }
#endif  // CONFIG_BITRATE_ACCURACY && CONFIG_THREE_PASS
 }

 if (av1_encode(cpi, dest, dest_size, frame_input, frame_params, frame_size) !=
     AOM_CODEC_OK) {
   return AOM_CODEC_ERROR;
 }

 // Set frame_input source to true source for psnr calculation.
 if (apply_filtering && is_psnr_calc_enabled(cpi)) {
   cpi->source = av1_realloc_and_scale_if_required(
       cm, source_buffer, &cpi->scaled_source, cm->features.interp_filter, 0,
       false, true, cpi->oxcf.border_in_pixels, cpi->alloc_pyramid);
   cpi->unscaled_source = source_buffer;
 }
#if CONFIG_COLLECT_COMPONENT_TIMING
 if (cpi->oxcf.pass == 2) end_timing(cpi, denoise_and_encode_time);
#endif
 return AOM_CODEC_OK;
}
#endif  // !CONFIG_REALTIME_ONLY

/*!\cond */
// Struct to keep track of relevant reference frame data.
typedef struct {
 int map_idx;
 int disp_order;
 int pyr_level;
 int used;
} RefBufMapData;
/*!\endcond */

// Comparison function to sort reference frames in ascending display order.
static int compare_map_idx_pair_asc(const void *a, const void *b) {
 if (((RefBufMapData *)a)->disp_order == ((RefBufMapData *)b)->disp_order) {
   return 0;
 } else if (((const RefBufMapData *)a)->disp_order >
            ((const RefBufMapData *)b)->disp_order) {
   return 1;
 } else {
   return -1;
 }
}

// Checks to see if a particular reference frame is already in the reference
// frame map.
static int is_in_ref_map(RefBufMapData *map, int disp_order, int n_frames) {
 for (int i = 0; i < n_frames; i++) {
   if (disp_order == map[i].disp_order) return 1;
 }
 return 0;
}

// Add a reference buffer index to a named reference slot.
static void add_ref_to_slot(RefBufMapData *ref, int *const remapped_ref_idx,
                           int frame) {
 remapped_ref_idx[frame - LAST_FRAME] = ref->map_idx;
 ref->used = 1;
}

// Threshold dictating when we are allowed to start considering
// leaving lowest level frames unmapped.
#define LOW_LEVEL_FRAMES_TR 5

// Find which reference buffer should be left out of the named mapping.
// This is because there are 8 reference buffers and only 7 named slots.
static void set_unmapped_ref(RefBufMapData *buffer_map, int n_bufs,
                            int n_min_level_refs, int min_level,
                            int cur_frame_disp) {
 int max_dist = 0;
 int unmapped_idx = -1;
 if (n_bufs <= ALTREF_FRAME) return;
 for (int i = 0; i < n_bufs; i++) {
   if (buffer_map[i].used) continue;
   if (buffer_map[i].pyr_level != min_level ||
       n_min_level_refs >= LOW_LEVEL_FRAMES_TR) {
     int dist = abs(cur_frame_disp - buffer_map[i].disp_order);
     if (dist > max_dist) {
       max_dist = dist;
       unmapped_idx = i;
     }
   }
 }
 assert(unmapped_idx >= 0 && "Unmapped reference not found");
 buffer_map[unmapped_idx].used = 1;
}

void av1_get_ref_frames(RefFrameMapPair ref_frame_map_pairs[REF_FRAMES],
                       int cur_frame_disp, const AV1_COMP *cpi, int gf_index,
                       int is_parallel_encode,
                       int remapped_ref_idx[REF_FRAMES]) {
 int buf_map_idx = 0;

 // Initialize reference frame mappings.
 for (int i = 0; i < REF_FRAMES; ++i) remapped_ref_idx[i] = INVALID_IDX;

#if !CONFIG_REALTIME_ONLY
 if (cpi->use_ducky_encode &&
     cpi->ducky_encode_info.frame_info.gop_mode == DUCKY_ENCODE_GOP_MODE_RCL) {
   for (int rf = LAST_FRAME; rf < REF_FRAMES; ++rf) {
     if (cpi->ppi->gf_group.ref_frame_list[gf_index][rf] != INVALID_IDX) {
       remapped_ref_idx[rf - LAST_FRAME] =
           cpi->ppi->gf_group.ref_frame_list[gf_index][rf];
     }
   }

   int valid_rf_idx = 0;
   static const int ref_frame_type_order[REF_FRAMES - LAST_FRAME] = {
     GOLDEN_FRAME,  ALTREF_FRAME, LAST_FRAME, BWDREF_FRAME,
     ALTREF2_FRAME, LAST2_FRAME,  LAST3_FRAME
   };
   for (int i = 0; i < REF_FRAMES - LAST_FRAME; i++) {
     int rf = ref_frame_type_order[i];
     if (remapped_ref_idx[rf - LAST_FRAME] != INVALID_IDX) {
       valid_rf_idx = remapped_ref_idx[rf - LAST_FRAME];
       break;
     }
   }

   for (int i = 0; i < REF_FRAMES; ++i) {
     if (remapped_ref_idx[i] == INVALID_IDX) {
       remapped_ref_idx[i] = valid_rf_idx;
     }
   }

   return;
 }
#endif  // !CONFIG_REALTIME_ONLY

 RefBufMapData buffer_map[REF_FRAMES];
 int n_bufs = 0;
 memset(buffer_map, 0, REF_FRAMES * sizeof(buffer_map[0]));
 int min_level = MAX_ARF_LAYERS;
 int max_level = 0;
 GF_GROUP *gf_group = &cpi->ppi->gf_group;
 int skip_ref_unmapping = 0;
 int is_one_pass_rt = is_one_pass_rt_params(cpi);

 // Go through current reference buffers and store display order, pyr level,
 // and map index.
 for (int map_idx = 0; map_idx < REF_FRAMES; map_idx++) {
   // Get reference frame buffer.
   RefFrameMapPair ref_pair = ref_frame_map_pairs[map_idx];
   if (ref_pair.disp_order == -1) continue;
   const int frame_order = ref_pair.disp_order;
   // Avoid duplicates.
   if (is_in_ref_map(buffer_map, frame_order, n_bufs)) continue;
   const int reference_frame_level = ref_pair.pyr_level;

   // Keep track of the lowest and highest levels that currently exist.
   if (reference_frame_level < min_level) min_level = reference_frame_level;
   if (reference_frame_level > max_level) max_level = reference_frame_level;

   buffer_map[n_bufs].map_idx = map_idx;
   buffer_map[n_bufs].disp_order = frame_order;
   buffer_map[n_bufs].pyr_level = reference_frame_level;
   buffer_map[n_bufs].used = 0;
   n_bufs++;
 }

 // Sort frames in ascending display order.
 qsort(buffer_map, n_bufs, sizeof(buffer_map[0]), compare_map_idx_pair_asc);

 int n_min_level_refs = 0;
 int closest_past_ref = -1;
 int golden_idx = -1;
 int altref_idx = -1;

 // Find the GOLDEN_FRAME and BWDREF_FRAME.
 // Also collect various stats about the reference frames for the remaining
 // mappings.
 for (int i = n_bufs - 1; i >= 0; i--) {
   if (buffer_map[i].pyr_level == min_level) {
     // Keep track of the number of lowest level frames.
     n_min_level_refs++;
     if (buffer_map[i].disp_order < cur_frame_disp && golden_idx == -1 &&
         remapped_ref_idx[GOLDEN_FRAME - LAST_FRAME] == INVALID_IDX) {
       // Save index for GOLDEN.
       golden_idx = i;
     } else if (buffer_map[i].disp_order > cur_frame_disp &&
                altref_idx == -1 &&
                remapped_ref_idx[ALTREF_FRAME - LAST_FRAME] == INVALID_IDX) {
       // Save index for ALTREF.
       altref_idx = i;
     }
   } else if (buffer_map[i].disp_order == cur_frame_disp) {
     // Map the BWDREF_FRAME if this is the show_existing_frame.
     add_ref_to_slot(&buffer_map[i], remapped_ref_idx, BWDREF_FRAME);
   }

   // During parallel encodes of lower layer frames, exclude the first frame
   // (frame_parallel_level 1) from being used for the reference assignment of
   // the second frame (frame_parallel_level 2).
   if (!is_one_pass_rt && gf_group->frame_parallel_level[gf_index] == 2 &&
       gf_group->frame_parallel_level[gf_index - 1] == 1 &&
       gf_group->update_type[gf_index - 1] == INTNL_ARF_UPDATE) {
     assert(gf_group->update_type[gf_index] == INTNL_ARF_UPDATE);
#if CONFIG_FPMT_TEST
     is_parallel_encode = (cpi->ppi->fpmt_unit_test_cfg == PARALLEL_ENCODE)
                              ? is_parallel_encode
                              : 0;
#endif  // CONFIG_FPMT_TEST
     // If parallel cpis are active, use ref_idx_to_skip, else, use display
     // index.
     assert(IMPLIES(is_parallel_encode, cpi->ref_idx_to_skip != INVALID_IDX));
     assert(IMPLIES(!is_parallel_encode,
                    gf_group->skip_frame_as_ref[gf_index] != INVALID_IDX));
     buffer_map[i].used = is_parallel_encode
                              ? (buffer_map[i].map_idx == cpi->ref_idx_to_skip)
                              : (buffer_map[i].disp_order ==
                                 gf_group->skip_frame_as_ref[gf_index]);
     // In case a ref frame is excluded from being used during assignment,
     // skip the call to set_unmapped_ref(). Applicable in steady state.
     if (buffer_map[i].used) skip_ref_unmapping = 1;
   }

   // Keep track of where the frames change from being past frames to future
   // frames.
   if (buffer_map[i].disp_order < cur_frame_disp && closest_past_ref < 0)
     closest_past_ref = i;
 }

 // Do not map GOLDEN and ALTREF based on their pyramid level if all reference
 // frames have the same level.
 if (n_min_level_refs <= n_bufs) {
   // Map the GOLDEN_FRAME.
   if (golden_idx > -1)
     add_ref_to_slot(&buffer_map[golden_idx], remapped_ref_idx, GOLDEN_FRAME);
   // Map the ALTREF_FRAME.
   if (altref_idx > -1)
     add_ref_to_slot(&buffer_map[altref_idx], remapped_ref_idx, ALTREF_FRAME);
 }

 // Find the buffer to be excluded from the mapping.
 if (!skip_ref_unmapping)
   set_unmapped_ref(buffer_map, n_bufs, n_min_level_refs, min_level,
                    cur_frame_disp);

 // Place past frames in LAST_FRAME, LAST2_FRAME, and LAST3_FRAME.
 for (int frame = LAST_FRAME; frame < GOLDEN_FRAME; frame++) {
   // Continue if the current ref slot is already full.
   if (remapped_ref_idx[frame - LAST_FRAME] != INVALID_IDX) continue;
   // Find the next unmapped reference buffer
   // in decreasing ouptut order relative to current picture.
   int next_buf_max = 0;
   int next_disp_order = INT_MIN;
   for (buf_map_idx = n_bufs - 1; buf_map_idx >= 0; buf_map_idx--) {
     if (!buffer_map[buf_map_idx].used &&
         buffer_map[buf_map_idx].disp_order < cur_frame_disp &&
         buffer_map[buf_map_idx].disp_order > next_disp_order) {
       next_disp_order = buffer_map[buf_map_idx].disp_order;
       next_buf_max = buf_map_idx;
     }
   }
   buf_map_idx = next_buf_max;
   if (buf_map_idx < 0) break;
   if (buffer_map[buf_map_idx].used) break;
   add_ref_to_slot(&buffer_map[buf_map_idx], remapped_ref_idx, frame);
 }

 // Place future frames (if there are any) in BWDREF_FRAME and ALTREF2_FRAME.
 for (int frame = BWDREF_FRAME; frame < REF_FRAMES; frame++) {
   // Continue if the current ref slot is already full.
   if (remapped_ref_idx[frame - LAST_FRAME] != INVALID_IDX) continue;
   // Find the next unmapped reference buffer
   // in increasing ouptut order relative to current picture.
   int next_buf_max = 0;
   int next_disp_order = INT_MAX;
   for (buf_map_idx = n_bufs - 1; buf_map_idx >= 0; buf_map_idx--) {
     if (!buffer_map[buf_map_idx].used &&
         buffer_map[buf_map_idx].disp_order > cur_frame_disp &&
         buffer_map[buf_map_idx].disp_order < next_disp_order) {
       next_disp_order = buffer_map[buf_map_idx].disp_order;
       next_buf_max = buf_map_idx;
     }
   }
   buf_map_idx = next_buf_max;
   if (buf_map_idx < 0) break;
   if (buffer_map[buf_map_idx].used) break;
   add_ref_to_slot(&buffer_map[buf_map_idx], remapped_ref_idx, frame);
 }

 // Place remaining past frames.
 buf_map_idx = closest_past_ref;
 for (int frame = LAST_FRAME; frame < REF_FRAMES; frame++) {
   // Continue if the current ref slot is already full.
   if (remapped_ref_idx[frame - LAST_FRAME] != INVALID_IDX) continue;
   // Find the next unmapped reference buffer.
   for (; buf_map_idx >= 0; buf_map_idx--) {
     if (!buffer_map[buf_map_idx].used) break;
   }
   if (buf_map_idx < 0) break;
   if (buffer_map[buf_map_idx].used) break;
   add_ref_to_slot(&buffer_map[buf_map_idx], remapped_ref_idx, frame);
 }

 // Place remaining future frames.
 buf_map_idx = n_bufs - 1;
 for (int frame = ALTREF_FRAME; frame >= LAST_FRAME; frame--) {
   // Continue if the current ref slot is already full.
   if (remapped_ref_idx[frame - LAST_FRAME] != INVALID_IDX) continue;
   // Find the next unmapped reference buffer.
   for (; buf_map_idx > closest_past_ref; buf_map_idx--) {
     if (!buffer_map[buf_map_idx].used) break;
   }
   if (buf_map_idx < 0) break;
   if (buffer_map[buf_map_idx].used) break;
   add_ref_to_slot(&buffer_map[buf_map_idx], remapped_ref_idx, frame);
 }

 // Fill any slots that are empty (should only happen for the first 7 frames).
 for (int i = 0; i < REF_FRAMES; ++i)
   if (remapped_ref_idx[i] == INVALID_IDX) remapped_ref_idx[i] = 0;
}

int av1_encode_strategy(AV1_COMP *const cpi, size_t *const size,
                       uint8_t *const dest, size_t dest_size,
                       unsigned int *frame_flags, int64_t *const time_stamp,
                       int64_t *const time_end,
                       const aom_rational64_t *const timestamp_ratio,
                       int *const pop_lookahead, int flush) {
 AV1EncoderConfig *const oxcf = &cpi->oxcf;
 AV1_COMMON *const cm = &cpi->common;
 GF_GROUP *gf_group = &cpi->ppi->gf_group;
 ExternalFlags *const ext_flags = &cpi->ext_flags;
 GFConfig *const gf_cfg = &oxcf->gf_cfg;

 EncodeFrameInput frame_input;
 EncodeFrameParams frame_params;
 size_t frame_size;
 memset(&frame_input, 0, sizeof(frame_input));
 memset(&frame_params, 0, sizeof(frame_params));
 frame_size = 0;

#if CONFIG_BITRATE_ACCURACY && CONFIG_THREE_PASS
 VBR_RATECTRL_INFO *vbr_rc_info = &cpi->vbr_rc_info;
 if (oxcf->pass == AOM_RC_THIRD_PASS && vbr_rc_info->ready == 0) {
   THIRD_PASS_FRAME_INFO frame_info[MAX_THIRD_PASS_BUF];
   av1_open_second_pass_log(cpi, 1);
   FILE *second_pass_log_stream = cpi->second_pass_log_stream;
   fseek(second_pass_log_stream, 0, SEEK_END);
   size_t file_size = ftell(second_pass_log_stream);
   rewind(second_pass_log_stream);
   size_t read_size = 0;
   while (read_size < file_size) {
     THIRD_PASS_GOP_INFO gop_info;
     struct aom_internal_error_info *error = cpi->common.error;
     // Read in GOP information from the second pass file.
     av1_read_second_pass_gop_info(second_pass_log_stream, &gop_info, error);
     TPL_INFO *tpl_info;
     AOM_CHECK_MEM_ERROR(cm->error, tpl_info, aom_malloc(sizeof(*tpl_info)));
     av1_read_tpl_info(tpl_info, second_pass_log_stream, error);
     // Read in per-frame info from second-pass encoding
     av1_read_second_pass_per_frame_info(second_pass_log_stream, frame_info,
                                         gop_info.num_frames, error);
     av1_vbr_rc_append_tpl_info(vbr_rc_info, tpl_info);
     read_size = ftell(second_pass_log_stream);
     aom_free(tpl_info);
   }
   av1_close_second_pass_log(cpi);
   if (cpi->oxcf.rc_cfg.mode == AOM_Q) {
     vbr_rc_info->base_q_index = cpi->oxcf.rc_cfg.cq_level;
     av1_vbr_rc_compute_q_indices(
         vbr_rc_info->base_q_index, vbr_rc_info->total_frame_count,
         vbr_rc_info->qstep_ratio_list, cm->seq_params->bit_depth,
         vbr_rc_info->q_index_list);
   } else {
     vbr_rc_info->base_q_index = av1_vbr_rc_info_estimate_base_q(
         vbr_rc_info->total_bit_budget, cm->seq_params->bit_depth,
         vbr_rc_info->scale_factors, vbr_rc_info->total_frame_count,
         vbr_rc_info->update_type_list, vbr_rc_info->qstep_ratio_list,
         vbr_rc_info->txfm_stats_list, vbr_rc_info->q_index_list, NULL);
   }
   vbr_rc_info->ready = 1;
#if CONFIG_RATECTRL_LOG
   rc_log_record_chunk_info(&cpi->rc_log, vbr_rc_info->base_q_index,
                            vbr_rc_info->total_frame_count);
#endif  // CONFIG_RATECTRL_LOG
 }
#endif  // CONFIG_BITRATE_ACCURACY && CONFIG_THREE_PASS

 // Check if we need to stuff more src frames
 if (flush == 0) {
   int srcbuf_size =
       av1_lookahead_depth(cpi->ppi->lookahead, cpi->compressor_stage);
   int pop_size =
       av1_lookahead_pop_sz(cpi->ppi->lookahead, cpi->compressor_stage);

   // Continue buffering look ahead buffer.
   if (srcbuf_size < pop_size) return -1;
 }

 if (!av1_lookahead_peek(cpi->ppi->lookahead, 0, cpi->compressor_stage)) {
#if !CONFIG_REALTIME_ONLY
   if (flush && oxcf->pass == AOM_RC_FIRST_PASS &&
       !cpi->ppi->twopass.first_pass_done) {
     av1_end_first_pass(cpi); /* get last stats packet */
     cpi->ppi->twopass.first_pass_done = 1;
   }
#endif
   return -1;
 }

 // TODO(sarahparker) finish bit allocation for one pass pyramid
 if (has_no_stats_stage(cpi)) {
   gf_cfg->gf_max_pyr_height =
       AOMMIN(gf_cfg->gf_max_pyr_height, USE_ALTREF_FOR_ONE_PASS);
   gf_cfg->gf_min_pyr_height =
       AOMMIN(gf_cfg->gf_min_pyr_height, gf_cfg->gf_max_pyr_height);
 }

 // Allocation of mi buffers.
 alloc_mb_mode_info_buffers(cpi);

 cpi->skip_tpl_setup_stats = 0;
#if !CONFIG_REALTIME_ONLY
 if (oxcf->pass != AOM_RC_FIRST_PASS) {
   TplParams *const tpl_data = &cpi->ppi->tpl_data;
   if (tpl_data->tpl_stats_pool[0] == NULL) {
     av1_setup_tpl_buffers(cpi->ppi, &cm->mi_params, oxcf->frm_dim_cfg.width,
                           oxcf->frm_dim_cfg.height, 0,
                           oxcf->gf_cfg.lag_in_frames);
   }
 }
 cpi->twopass_frame.this_frame = NULL;
 const int use_one_pass_rt_params = is_one_pass_rt_params(cpi);
 if (!use_one_pass_rt_params && !is_stat_generation_stage(cpi)) {
#if CONFIG_COLLECT_COMPONENT_TIMING
   start_timing(cpi, av1_get_second_pass_params_time);
#endif

   // Initialise frame_level_rate_correction_factors with value previous
   // to the parallel frames.
   if (cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0) {
     for (int i = 0; i < RATE_FACTOR_LEVELS; i++) {
       cpi->rc.frame_level_rate_correction_factors[i] =
#if CONFIG_FPMT_TEST
           (cpi->ppi->fpmt_unit_test_cfg == PARALLEL_SIMULATION_ENCODE)
               ? cpi->ppi->p_rc.temp_rate_correction_factors[i]
               :
#endif  // CONFIG_FPMT_TEST
               cpi->ppi->p_rc.rate_correction_factors[i];
     }
   }

   // copy mv_stats from ppi to frame_level cpi.
   cpi->mv_stats = cpi->ppi->mv_stats;
   av1_get_second_pass_params(cpi, &frame_params, *frame_flags);
#if CONFIG_COLLECT_COMPONENT_TIMING
   end_timing(cpi, av1_get_second_pass_params_time);
#endif
 }
#endif

 if (!is_stat_generation_stage(cpi)) {
   // TODO(jingning): fwd key frame always uses show existing frame?
   if (gf_group->update_type[cpi->gf_frame_index] == OVERLAY_UPDATE &&
       gf_group->refbuf_state[cpi->gf_frame_index] == REFBUF_RESET) {
     frame_params.show_existing_frame = 1;
   } else {
     frame_params.show_existing_frame =
         (cpi->ppi->show_existing_alt_ref &&
          gf_group->update_type[cpi->gf_frame_index] == OVERLAY_UPDATE) ||
         gf_group->update_type[cpi->gf_frame_index] == INTNL_OVERLAY_UPDATE;
   }
   frame_params.show_existing_frame &= allow_show_existing(cpi, *frame_flags);

   // Special handling to reset 'show_existing_frame' in case of dropped
   // frames.
   if (oxcf->rc_cfg.drop_frames_water_mark &&
       (gf_group->update_type[cpi->gf_frame_index] == OVERLAY_UPDATE ||
        gf_group->update_type[cpi->gf_frame_index] == INTNL_OVERLAY_UPDATE)) {
     // During the encode of an OVERLAY_UPDATE/INTNL_OVERLAY_UPDATE frame, loop
     // over the gf group to check if the corresponding
     // ARF_UPDATE/INTNL_ARF_UPDATE frame was dropped.
     int cur_disp_idx = gf_group->display_idx[cpi->gf_frame_index];
     for (int idx = 0; idx < cpi->gf_frame_index; idx++) {
       if (cur_disp_idx == gf_group->display_idx[idx]) {
         assert(IMPLIES(
             gf_group->update_type[cpi->gf_frame_index] == OVERLAY_UPDATE,
             gf_group->update_type[idx] == ARF_UPDATE));
         assert(IMPLIES(gf_group->update_type[cpi->gf_frame_index] ==
                            INTNL_OVERLAY_UPDATE,
                        gf_group->update_type[idx] == INTNL_ARF_UPDATE));
         // Reset show_existing_frame and set cpi->is_dropped_frame to true if
         // the frame was dropped during its first encode.
         if (gf_group->is_frame_dropped[idx]) {
           frame_params.show_existing_frame = 0;
           assert(!cpi->is_dropped_frame);
           cpi->is_dropped_frame = true;
         }
         break;
       }
     }
   }

   // Reset show_existing_alt_ref decision to 0 after it is used.
   if (gf_group->update_type[cpi->gf_frame_index] == OVERLAY_UPDATE) {
     cpi->ppi->show_existing_alt_ref = 0;
   }
 } else {
   frame_params.show_existing_frame = 0;
 }

 struct lookahead_entry *source = NULL;
 struct lookahead_entry *last_source = NULL;
 if (frame_params.show_existing_frame) {
   source = av1_lookahead_peek(cpi->ppi->lookahead, 0, cpi->compressor_stage);
   *pop_lookahead = 1;
   frame_params.show_frame = 1;
 } else {
   source = choose_frame_source(cpi, &flush, pop_lookahead, &last_source,
                                &frame_params.show_frame);
 }

 if (source == NULL) {  // If no source was found, we can't encode a frame.
#if !CONFIG_REALTIME_ONLY
   if (flush && oxcf->pass == AOM_RC_FIRST_PASS &&
       !cpi->ppi->twopass.first_pass_done) {
     av1_end_first_pass(cpi); /* get last stats packet */
     cpi->ppi->twopass.first_pass_done = 1;
   }
#endif
   return -1;
 }

 // reset src_offset to allow actual encode call for this frame to get its
 // source.
 gf_group->src_offset[cpi->gf_frame_index] = 0;

 // Source may be changed if temporal filtered later.
 frame_input.source = &source->img;
 if ((cpi->ppi->use_svc || cpi->rc.prev_frame_is_dropped) &&
     last_source != NULL)
   av1_svc_set_last_source(cpi, &frame_input, &last_source->img);
 else
   frame_input.last_source = last_source != NULL ? &last_source->img : NULL;
 frame_input.ts_duration = source->ts_end - source->ts_start;
 // Save unfiltered source. It is used in av1_get_second_pass_params().
 cpi->unfiltered_source = frame_input.source;

 *time_stamp = source->ts_start;
 *time_end = source->ts_end;
 if (source->ts_start < cpi->time_stamps.first_ts_start) {
   cpi->time_stamps.first_ts_start = source->ts_start;
   cpi->time_stamps.prev_ts_end = source->ts_start;
 }

 av1_apply_encoding_flags(cpi, source->flags);
 *frame_flags = (source->flags & AOM_EFLAG_FORCE_KF) ? FRAMEFLAGS_KEY : 0;

#if CONFIG_FPMT_TEST
 if (cpi->ppi->fpmt_unit_test_cfg == PARALLEL_SIMULATION_ENCODE) {
   if (cpi->ppi->gf_group.frame_parallel_level[cpi->gf_frame_index] > 0) {
     cpi->framerate = cpi->temp_framerate;
   }
 }
#endif  // CONFIG_FPMT_TEST

 // Shown frames and arf-overlay frames need frame-rate considering
 if (frame_params.show_frame)
   adjust_frame_rate(cpi, source->ts_start, source->ts_end);

 if (!frame_params.show_existing_frame) {
#if !CONFIG_REALTIME_ONLY
   if (cpi->film_grain_table) {
     cm->cur_frame->film_grain_params_present = aom_film_grain_table_lookup(
         cpi->film_grain_table, *time_stamp, *time_end, 0 /* =erase */,
         &cm->film_grain_params);
   } else {
     cm->cur_frame->film_grain_params_present =
         cm->seq_params->film_grain_params_present;
   }
#endif
   // only one operating point supported now
   const int64_t pts64 = ticks_to_timebase_units(timestamp_ratio, *time_stamp);
   if (pts64 < 0 || pts64 > UINT32_MAX) return AOM_CODEC_ERROR;

   cm->frame_presentation_time = (uint32_t)pts64;
 }

#if CONFIG_COLLECT_COMPONENT_TIMING
 start_timing(cpi, av1_get_one_pass_rt_params_time);
#endif
#if CONFIG_REALTIME_ONLY
 av1_get_one_pass_rt_params(cpi, &frame_params.frame_type, &frame_input,
                            *frame_flags);
 if (use_rtc_reference_structure_one_layer(cpi))
   av1_set_rtc_reference_structure_one_layer(cpi, cpi->gf_frame_index == 0);
#else
 if (use_one_pass_rt_params) {
   av1_get_one_pass_rt_params(cpi, &frame_params.frame_type, &frame_input,
                              *frame_flags);
   if (use_rtc_reference_structure_one_layer(cpi))
     av1_set_rtc_reference_structure_one_layer(cpi, cpi->gf_frame_index == 0);
 }
#endif
#if CONFIG_COLLECT_COMPONENT_TIMING
 end_timing(cpi, av1_get_one_pass_rt_params_time);
#endif

 FRAME_UPDATE_TYPE frame_update_type =
     get_frame_update_type(gf_group, cpi->gf_frame_index);

 if (frame_params.show_existing_frame &&
     frame_params.frame_type != KEY_FRAME) {
   // Force show-existing frames to be INTER, except forward keyframes
   frame_params.frame_type = INTER_FRAME;
 }

 // Per-frame encode speed.  In theory this can vary, but things may have
 // been written assuming speed-level will not change within a sequence, so
 // this parameter should be used with caution.
 frame_params.speed = oxcf->speed;

#if !CONFIG_REALTIME_ONLY
 // Set forced key frames when necessary. For two-pass encoding / lap mode,
 // this is already handled by av1_get_second_pass_params. However when no
 // stats are available, we still need to check if the new frame is a keyframe.
 // For one pass rt, this is already checked in av1_get_one_pass_rt_params.
 if (!use_one_pass_rt_params &&
     (is_stat_generation_stage(cpi) || has_no_stats_stage(cpi))) {
   // Current frame is coded as a key-frame for any of the following cases:
   // 1) First frame of a video
   // 2) For all-intra frame encoding
   // 3) When a key-frame is forced
   const int kf_requested =
       (cm->current_frame.frame_number == 0 ||
        oxcf->kf_cfg.key_freq_max == 0 || (*frame_flags & FRAMEFLAGS_KEY));
   if (kf_requested && frame_update_type != OVERLAY_UPDATE &&
       frame_update_type != INTNL_OVERLAY_UPDATE) {
     frame_params.frame_type = KEY_FRAME;
   } else if (is_stat_generation_stage(cpi)) {
     // For stats generation, set the frame type to inter here.
     frame_params.frame_type = INTER_FRAME;
   }
 }
#endif

 // Work out some encoding parameters specific to the pass:
 if (has_no_stats_stage(cpi) && oxcf->q_cfg.aq_mode == CYCLIC_REFRESH_AQ) {
   av1_cyclic_refresh_update_parameters(cpi);
 } else if (is_stat_generation_stage(cpi)) {
   cpi->td.mb.e_mbd.lossless[0] = is_lossless_requested(&oxcf->rc_cfg);
 } else if (is_stat_consumption_stage(cpi)) {
#if CONFIG_MISMATCH_DEBUG
   mismatch_move_frame_idx_w();
#endif
#if TXCOEFF_COST_TIMER
   cm->txcoeff_cost_timer = 0;
   cm->txcoeff_cost_count = 0;
#endif
 }

 if (!is_stat_generation_stage(cpi))
   set_ext_overrides(cm, &frame_params, ext_flags);

 // Shown keyframes and S frames refresh all reference buffers
 const int force_refresh_all =
     ((frame_params.frame_type == KEY_FRAME && frame_params.show_frame) ||
      frame_params.frame_type == S_FRAME) &&
     !frame_params.show_existing_frame;

 av1_configure_buffer_updates(
     cpi, &frame_params.refresh_frame, frame_update_type,
     gf_group->refbuf_state[cpi->gf_frame_index], force_refresh_all);

 if (!is_stat_generation_stage(cpi)) {
   const YV12_BUFFER_CONFIG *ref_frame_buf[INTER_REFS_PER_FRAME];

   RefFrameMapPair ref_frame_map_pairs[REF_FRAMES];
   init_ref_map_pair(cpi, ref_frame_map_pairs);
   const int order_offset = gf_group->arf_src_offset[cpi->gf_frame_index];
   const int cur_frame_disp =
       cpi->common.current_frame.frame_number + order_offset;

   int get_ref_frames = 0;
#if CONFIG_FPMT_TEST
   get_ref_frames =
       (cpi->ppi->fpmt_unit_test_cfg == PARALLEL_SIMULATION_ENCODE) ? 1 : 0;
#endif  // CONFIG_FPMT_TEST
   if (get_ref_frames ||
       gf_group->frame_parallel_level[cpi->gf_frame_index] == 0) {
     if (!ext_flags->refresh_frame.update_pending) {
       av1_get_ref_frames(ref_frame_map_pairs, cur_frame_disp, cpi,
                          cpi->gf_frame_index, 1, cm->remapped_ref_idx);
     } else if (cpi->ppi->rtc_ref.set_ref_frame_config ||
                use_rtc_reference_structure_one_layer(cpi)) {
       for (unsigned int i = 0; i < INTER_REFS_PER_FRAME; i++)
         cm->remapped_ref_idx[i] = cpi->ppi->rtc_ref.ref_idx[i];
     }
   }

   // Get the reference frames
   bool has_ref_frames = false;
   for (int i = 0; i < INTER_REFS_PER_FRAME; ++i) {
     const RefCntBuffer *ref_frame =
         get_ref_frame_buf(cm, ref_frame_priority_order[i]);
     ref_frame_buf[i] = ref_frame != NULL ? &ref_frame->buf : NULL;
     if (ref_frame != NULL) has_ref_frames = true;
   }
   if (!has_ref_frames && (frame_params.frame_type == INTER_FRAME ||
                           frame_params.frame_type == S_FRAME)) {
     return AOM_CODEC_ERROR;
   }

   // Work out which reference frame slots may be used.
   frame_params.ref_frame_flags =
       get_ref_frame_flags(&cpi->sf, is_one_pass_rt_params(cpi), ref_frame_buf,
                           ext_flags->ref_frame_flags);

   // Set primary_ref_frame of non-reference frames as PRIMARY_REF_NONE.
   if (cpi->ppi->gf_group.is_frame_non_ref[cpi->gf_frame_index]) {
     frame_params.primary_ref_frame = PRIMARY_REF_NONE;
   } else {
     frame_params.primary_ref_frame =
         choose_primary_ref_frame(cpi, &frame_params);
   }

   frame_params.order_offset = gf_group->arf_src_offset[cpi->gf_frame_index];

   // Call av1_get_refresh_frame_flags() if refresh index not available.
   if (!cpi->refresh_idx_available) {
     frame_params.refresh_frame_flags = av1_get_refresh_frame_flags(
         cpi, &frame_params, frame_update_type, cpi->gf_frame_index,
         cur_frame_disp, ref_frame_map_pairs);
   } else {
     assert(cpi->ref_refresh_index != INVALID_IDX);
     frame_params.refresh_frame_flags = (1 << cpi->ref_refresh_index);
   }

   // Make the frames marked as is_frame_non_ref to non-reference frames.
   if (gf_group->is_frame_non_ref[cpi->gf_frame_index])
     frame_params.refresh_frame_flags = 0;

   frame_params.existing_fb_idx_to_show = INVALID_IDX;
   // Find the frame buffer to show based on display order.
   if (frame_params.show_existing_frame) {
     for (int frame = 0; frame < REF_FRAMES; frame++) {
       const RefCntBuffer *const buf = cm->ref_frame_map[frame];
       if (buf == NULL) continue;
       const int frame_order = (int)buf->display_order_hint;
       if (frame_order == cur_frame_disp)
         frame_params.existing_fb_idx_to_show = frame;
     }
   }
 }

 // The way frame_params->remapped_ref_idx is setup is a placeholder.
 // Currently, reference buffer assignment is done by update_ref_frame_map()
 // which is called by high-level strategy AFTER encoding a frame.  It
 // modifies cm->remapped_ref_idx.  If you want to use an alternative method
 // to determine reference buffer assignment, just put your assignments into
 // frame_params->remapped_ref_idx here and they will be used when encoding
 // this frame.  If frame_params->remapped_ref_idx is setup independently of
 // cm->remapped_ref_idx then update_ref_frame_map() will have no effect.
 memcpy(frame_params.remapped_ref_idx, cm->remapped_ref_idx,
        REF_FRAMES * sizeof(*cm->remapped_ref_idx));

 cpi->td.mb.rdmult_delta_qindex = cpi->td.mb.delta_qindex = 0;

 if (!frame_params.show_existing_frame) {
   cm->quant_params.using_qmatrix = oxcf->q_cfg.using_qm;
 }

 const int is_intra_frame = frame_params.frame_type == KEY_FRAME ||
                            frame_params.frame_type == INTRA_ONLY_FRAME;
 FeatureFlags *const features = &cm->features;
 if (!is_stat_generation_stage(cpi) &&
     (oxcf->pass == AOM_RC_ONE_PASS || oxcf->pass >= AOM_RC_SECOND_PASS) &&
     is_intra_frame) {
   av1_set_screen_content_options(cpi, features);
 }

#if CONFIG_REALTIME_ONLY
 if (av1_encode(cpi, dest, dest_size, &frame_input, &frame_params,
                &frame_size) != AOM_CODEC_OK) {
   return AOM_CODEC_ERROR;
 }
#else
 if (has_no_stats_stage(cpi) && oxcf->mode == REALTIME &&
     gf_cfg->lag_in_frames == 0) {
   if (av1_encode(cpi, dest, dest_size, &frame_input, &frame_params,
                  &frame_size) != AOM_CODEC_OK) {
     return AOM_CODEC_ERROR;
   }
 } else if (denoise_and_encode(cpi, dest, dest_size, &frame_input,
                               &frame_params, &frame_size) != AOM_CODEC_OK) {
   return AOM_CODEC_ERROR;
 }
#endif  // CONFIG_REALTIME_ONLY

 // This is used in rtc temporal filter case. Use true source in the PSNR
 // calculation.
 if (is_psnr_calc_enabled(cpi) && cpi->sf.rt_sf.use_rtc_tf) {
   assert(cpi->orig_source.buffer_alloc_sz > 0);
   cpi->source = &cpi->orig_source;
 }

 if (!is_stat_generation_stage(cpi)) {
   // First pass doesn't modify reference buffer assignment or produce frame
   // flags
   update_frame_flags(&cpi->common, &cpi->refresh_frame, frame_flags);
   set_additional_frame_flags(cm, frame_flags);
 }

#if !CONFIG_REALTIME_ONLY
#if TXCOEFF_COST_TIMER
 if (!is_stat_generation_stage(cpi)) {
   cm->cum_txcoeff_cost_timer += cm->txcoeff_cost_timer;
   fprintf(stderr,
           "\ntxb coeff cost block number: %ld, frame time: %ld, cum time %ld "
           "in us\n",
           cm->txcoeff_cost_count, cm->txcoeff_cost_timer,
           cm->cum_txcoeff_cost_timer);
 }
#endif
#endif  // !CONFIG_REALTIME_ONLY

#if CONFIG_TUNE_VMAF
 if (!is_stat_generation_stage(cpi) &&
     (oxcf->tune_cfg.tuning >= AOM_TUNE_VMAF_WITH_PREPROCESSING &&
      oxcf->tune_cfg.tuning <= AOM_TUNE_VMAF_NEG_MAX_GAIN)) {
   av1_update_vmaf_curve(cpi);
 }
#endif

 *size = frame_size;

 // Leave a signal for a higher level caller about if this frame is droppable
 if (*size > 0) {
   cpi->droppable =
       is_frame_droppable(&cpi->ppi->rtc_ref, &ext_flags->refresh_frame);
 }

 // For SVC, or when frame-dropper is enabled:
 // keep track of the (unscaled) source corresponding to the refresh of LAST
 // reference (base temporal layer - TL0). Copy only for the
 // top spatial enhancement layer so all spatial layers of the next
 // superframe have last_source to be aligned with previous TL0 superframe.
 // Avoid cases where resolution changes for unscaled source (top spatial
 // layer). Only needs to be done for frame that are encoded (size > 0).
 if (*size > 0 &&
     (cpi->ppi->use_svc || cpi->oxcf.rc_cfg.drop_frames_water_mark > 0) &&
     cpi->svc.spatial_layer_id == cpi->svc.number_spatial_layers - 1 &&
     cpi->svc.temporal_layer_id == 0 &&
     cpi->unscaled_source->y_width == cpi->svc.source_last_TL0.y_width &&
     cpi->unscaled_source->y_height == cpi->svc.source_last_TL0.y_height) {
   aom_yv12_copy_y(cpi->unscaled_source, &cpi->svc.source_last_TL0, 1);
   aom_yv12_copy_u(cpi->unscaled_source, &cpi->svc.source_last_TL0, 1);
   aom_yv12_copy_v(cpi->unscaled_source, &cpi->svc.source_last_TL0, 1);
 }

 return AOM_CODEC_OK;
}