The Tor Browser: media/libvpx/vp9/encoder/vp9_firstpass.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_firstpass.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_firstpass.c

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
permissions: -rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <math.h>
 #include <limits.h>
 #include <stdio.h>
 #include "vp9/encoder/vp9_block.h"
 #include "vp9/encoder/vp9_onyx_int.h"
 #include "vp9/encoder/vp9_variance.h"
 #include "vp9/encoder/vp9_encodeintra.h"
 #include "vp9/encoder/vp9_mcomp.h"
 #include "vp9/encoder/vp9_firstpass.h"
 #include "vpx_scale/vpx_scale.h"
 #include "vp9/encoder/vp9_encodeframe.h"
 #include "vp9/encoder/vp9_encodemb.h"
 #include "vp9/common/vp9_extend.h"
 #include "vp9/common/vp9_systemdependent.h"
 #include "vpx_mem/vpx_mem.h"
 #include "vpx_scale/yv12config.h"
 #include "vp9/encoder/vp9_quantize.h"
 #include "vp9/encoder/vp9_rdopt.h"
 #include "vp9/encoder/vp9_ratectrl.h"
 #include "vp9/common/vp9_quant_common.h"
 #include "vp9/common/vp9_entropymv.h"
 #include "vp9/encoder/vp9_encodemv.h"
 #include "vp9/encoder/vp9_vaq.h"
 #include "./vpx_scale_rtcd.h"
 // TODO(jkoleszar): for setup_dst_planes
 #include "vp9/common/vp9_reconinter.h"
 #define OUTPUT_FPF 0
 #define IIFACTOR   12.5
 #define IIKFACTOR1 12.5
 #define IIKFACTOR2 15.0
 #define RMAX       512.0
 #define GF_RMAX    96.0
 #define ERR_DIVISOR   150.0
 #define MIN_DECAY_FACTOR 0.1
 #define KF_MB_INTRA_MIN 150
 #define GF_MB_INTRA_MIN 100
 #define DOUBLE_DIVIDE_CHECK(x) ((x) < 0 ? (x) - 0.000001 : (x) + 0.000001)
 #define POW1 (double)cpi->oxcf.two_pass_vbrbias/100.0
 #define POW2 (double)cpi->oxcf.two_pass_vbrbias/100.0
 static void swap_yv12(YV12_BUFFER_CONFIG *a, YV12_BUFFER_CONFIG *b) {
   YV12_BUFFER_CONFIG temp = *a;
   *a = *b;
   *b = temp;
 }
 static void find_next_key_frame(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame);
 static int select_cq_level(int qindex) {
   int ret_val = QINDEX_RANGE - 1;
   int i;
   double target_q = (vp9_convert_qindex_to_q(qindex) * 0.5847) + 1.0;
   for (i = 0; i < QINDEX_RANGE; i++) {
     if (target_q <= vp9_convert_qindex_to_q(i)) {
       ret_val = i;
       break;
     }
   }
   return ret_val;
 }
 // Resets the first pass file to the given position using a relative seek from
 // the current position.
 static void reset_fpf_position(VP9_COMP *cpi, FIRSTPASS_STATS *position) {
   cpi->twopass.stats_in = position;
 }
 static int lookup_next_frame_stats(VP9_COMP *cpi, FIRSTPASS_STATS *next_frame) {
   if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end)
     return EOF;
   *next_frame = *cpi->twopass.stats_in;
   return 1;
 }
 // Read frame stats at an offset from the current position
 static int read_frame_stats(VP9_COMP *cpi,
                             FIRSTPASS_STATS *frame_stats,
                             int offset) {
   FIRSTPASS_STATS *fps_ptr = cpi->twopass.stats_in;
   // Check legality of offset
   if (offset >= 0) {
     if (&fps_ptr[offset] >= cpi->twopass.stats_in_end)
       return EOF;
   } else if (offset < 0) {
     if (&fps_ptr[offset] < cpi->twopass.stats_in_start)
       return EOF;
   }
   *frame_stats = fps_ptr[offset];
   return 1;
 }
 static int input_stats(VP9_COMP *cpi, FIRSTPASS_STATS *fps) {
   if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end)
     return EOF;
   *fps = *cpi->twopass.stats_in;
   cpi->twopass.stats_in =
     (void *)((char *)cpi->twopass.stats_in + sizeof(FIRSTPASS_STATS));
   return 1;
 }
 static void output_stats(const VP9_COMP            *cpi,
                          struct vpx_codec_pkt_list *pktlist,
                          FIRSTPASS_STATS            *stats) {
   struct vpx_codec_cx_pkt pkt;
   pkt.kind = VPX_CODEC_STATS_PKT;
   pkt.data.twopass_stats.buf = stats;
   pkt.data.twopass_stats.sz = sizeof(FIRSTPASS_STATS);
   vpx_codec_pkt_list_add(pktlist, &pkt);
 // TEMP debug code
 #if OUTPUT_FPF
   {
     FILE *fpfile;
     fpfile = fopen("firstpass.stt", "a");
     fprintf(stdout, "%12.0f %12.0f %12.0f %12.0f %12.0f %12.4f %12.4f"
             "%12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f"
             "%12.0f %12.0f %12.4f %12.0f %12.0f %12.4f\n",
             stats->frame,
             stats->intra_error,
             stats->coded_error,
             stats->sr_coded_error,
             stats->ssim_weighted_pred_err,
             stats->pcnt_inter,
             stats->pcnt_motion,
             stats->pcnt_second_ref,
             stats->pcnt_neutral,
             stats->MVr,
             stats->mvr_abs,
             stats->MVc,
             stats->mvc_abs,
             stats->MVrv,
             stats->MVcv,
             stats->mv_in_out_count,
             stats->new_mv_count,
             stats->count,
             stats->duration);
     fclose(fpfile);
   }
 #endif
 }
 static void zero_stats(FIRSTPASS_STATS *section) {
   section->frame      = 0.0;
   section->intra_error = 0.0;
   section->coded_error = 0.0;
   section->sr_coded_error = 0.0;
   section->ssim_weighted_pred_err = 0.0;
   section->pcnt_inter  = 0.0;
   section->pcnt_motion  = 0.0;
   section->pcnt_second_ref = 0.0;
   section->pcnt_neutral = 0.0;
   section->MVr        = 0.0;
   section->mvr_abs     = 0.0;
   section->MVc        = 0.0;
   section->mvc_abs     = 0.0;
   section->MVrv       = 0.0;
   section->MVcv       = 0.0;
   section->mv_in_out_count  = 0.0;
   section->new_mv_count = 0.0;
   section->count      = 0.0;
   section->duration   = 1.0;
 }
 static void accumulate_stats(FIRSTPASS_STATS *section, FIRSTPASS_STATS *frame) {
   section->frame += frame->frame;
   section->intra_error += frame->intra_error;
   section->coded_error += frame->coded_error;
   section->sr_coded_error += frame->sr_coded_error;
   section->ssim_weighted_pred_err += frame->ssim_weighted_pred_err;
   section->pcnt_inter  += frame->pcnt_inter;
   section->pcnt_motion += frame->pcnt_motion;
   section->pcnt_second_ref += frame->pcnt_second_ref;
   section->pcnt_neutral += frame->pcnt_neutral;
   section->MVr        += frame->MVr;
   section->mvr_abs     += frame->mvr_abs;
   section->MVc        += frame->MVc;
   section->mvc_abs     += frame->mvc_abs;
   section->MVrv       += frame->MVrv;
   section->MVcv       += frame->MVcv;
   section->mv_in_out_count  += frame->mv_in_out_count;
   section->new_mv_count += frame->new_mv_count;
   section->count      += frame->count;
   section->duration   += frame->duration;
 }
 static void subtract_stats(FIRSTPASS_STATS *section, FIRSTPASS_STATS *frame) {
   section->frame -= frame->frame;
   section->intra_error -= frame->intra_error;
   section->coded_error -= frame->coded_error;
   section->sr_coded_error -= frame->sr_coded_error;
   section->ssim_weighted_pred_err -= frame->ssim_weighted_pred_err;
   section->pcnt_inter  -= frame->pcnt_inter;
   section->pcnt_motion -= frame->pcnt_motion;
   section->pcnt_second_ref -= frame->pcnt_second_ref;
   section->pcnt_neutral -= frame->pcnt_neutral;
   section->MVr        -= frame->MVr;
   section->mvr_abs     -= frame->mvr_abs;
   section->MVc        -= frame->MVc;
   section->mvc_abs     -= frame->mvc_abs;
   section->MVrv       -= frame->MVrv;
   section->MVcv       -= frame->MVcv;
   section->mv_in_out_count  -= frame->mv_in_out_count;
   section->new_mv_count -= frame->new_mv_count;
   section->count      -= frame->count;
   section->duration   -= frame->duration;
 }
 static void avg_stats(FIRSTPASS_STATS *section) {
   if (section->count < 1.0)
     return;
   section->intra_error /= section->count;
   section->coded_error /= section->count;
   section->sr_coded_error /= section->count;
   section->ssim_weighted_pred_err /= section->count;
   section->pcnt_inter  /= section->count;
   section->pcnt_second_ref /= section->count;
   section->pcnt_neutral /= section->count;
   section->pcnt_motion /= section->count;
   section->MVr        /= section->count;
   section->mvr_abs     /= section->count;
   section->MVc        /= section->count;
   section->mvc_abs     /= section->count;
   section->MVrv       /= section->count;
   section->MVcv       /= section->count;
   section->mv_in_out_count   /= section->count;
   section->duration   /= section->count;
 }
 // Calculate a modified Error used in distributing bits between easier and
 // harder frames.
 static double calculate_modified_err(VP9_COMP *cpi,
                                      FIRSTPASS_STATS *this_frame) {
   const FIRSTPASS_STATS *const stats = &cpi->twopass.total_stats;
   const double av_err = stats->ssim_weighted_pred_err / stats->count;
   const double this_err = this_frame->ssim_weighted_pred_err;
   return av_err * pow(this_err / DOUBLE_DIVIDE_CHECK(av_err),
                       this_err > av_err ? POW1 : POW2);
 }
 static const double weight_table[256] = {
 .020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
 .020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
 .020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
 .020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
 .020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.031250, 0.062500,
 .093750, 0.125000, 0.156250, 0.187500, 0.218750, 0.250000, 0.281250,
 .312500, 0.343750, 0.375000, 0.406250, 0.437500, 0.468750, 0.500000,
 .531250, 0.562500, 0.593750, 0.625000, 0.656250, 0.687500, 0.718750,
 .750000, 0.781250, 0.812500, 0.843750, 0.875000, 0.906250, 0.937500,
 .968750, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
 .000000, 1.000000, 1.000000, 1.000000
 };
 static double simple_weight(YV12_BUFFER_CONFIG *source) {
   int i, j;
   uint8_t *src = source->y_buffer;
   double sum_weights = 0.0;
   // Loop through the Y plane examining levels and creating a weight for
   // the image.
   i = source->y_height;
   do {
     j = source->y_width;
     do {
       sum_weights += weight_table[ *src];
       src++;
     } while (--j);
     src -= source->y_width;
     src += source->y_stride;
   } while (--i);
   sum_weights /= (source->y_height * source->y_width);
   return sum_weights;
 }
 // This function returns the current per frame maximum bitrate target.
 static int frame_max_bits(VP9_COMP *cpi) {
   // Max allocation for a single frame based on the max section guidelines
   // passed in and how many bits are left.
   // For VBR base this on the bits and frames left plus the
   // two_pass_vbrmax_section rate passed in by the user.
   const double max_bits = (1.0 * cpi->twopass.bits_left /
       (cpi->twopass.total_stats.count - cpi->common.current_video_frame)) *
       (cpi->oxcf.two_pass_vbrmax_section / 100.0);
   // Trap case where we are out of bits.
   return MAX((int)max_bits, 0);
 }
 void vp9_init_first_pass(VP9_COMP *cpi) {
   zero_stats(&cpi->twopass.total_stats);
 }
 void vp9_end_first_pass(VP9_COMP *cpi) {
   output_stats(cpi, cpi->output_pkt_list, &cpi->twopass.total_stats);
 }
 static void zz_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
                              YV12_BUFFER_CONFIG *recon_buffer,
                              int *best_motion_err, int recon_yoffset) {
   MACROBLOCKD *const xd = &x->e_mbd;
   // Set up pointers for this macro block recon buffer
   xd->plane[0].pre[0].buf = recon_buffer->y_buffer + recon_yoffset;
   switch (xd->mi_8x8[0]->mbmi.sb_type) {
     case BLOCK_8X8:
       vp9_mse8x8(x->plane[0].src.buf, x->plane[0].src.stride,
                  xd->plane[0].pre[0].buf, xd->plane[0].pre[0].stride,
                  (unsigned int *)(best_motion_err));
       break;
     case BLOCK_16X8:
       vp9_mse16x8(x->plane[0].src.buf, x->plane[0].src.stride,
                   xd->plane[0].pre[0].buf, xd->plane[0].pre[0].stride,
                   (unsigned int *)(best_motion_err));
       break;
     case BLOCK_8X16:
       vp9_mse8x16(x->plane[0].src.buf, x->plane[0].src.stride,
                   xd->plane[0].pre[0].buf, xd->plane[0].pre[0].stride,
                   (unsigned int *)(best_motion_err));
       break;
     default:
       vp9_mse16x16(x->plane[0].src.buf, x->plane[0].src.stride,
                    xd->plane[0].pre[0].buf, xd->plane[0].pre[0].stride,
                    (unsigned int *)(best_motion_err));
       break;
   }
 }
 static void first_pass_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
                                      int_mv *ref_mv, MV *best_mv,
                                      YV12_BUFFER_CONFIG *recon_buffer,
                                      int *best_motion_err, int recon_yoffset) {
   MACROBLOCKD *const xd = &x->e_mbd;
   int num00;
   int_mv tmp_mv;
   int_mv ref_mv_full;
   int tmp_err;
   int step_param = 3;
   int further_steps = (MAX_MVSEARCH_STEPS - 1) - step_param;
   int n;
   vp9_variance_fn_ptr_t v_fn_ptr =
       cpi->fn_ptr[xd->mi_8x8[0]->mbmi.sb_type];
   int new_mv_mode_penalty = 256;
   int sr = 0;
   int quart_frm = MIN(cpi->common.width, cpi->common.height);
   // refine the motion search range accroding to the frame dimension
   // for first pass test
   while ((quart_frm << sr) < MAX_FULL_PEL_VAL)
     sr++;
   if (sr)
     sr--;
   step_param    += sr;
   further_steps -= sr;
   // override the default variance function to use MSE
   switch (xd->mi_8x8[0]->mbmi.sb_type) {
     case BLOCK_8X8:
       v_fn_ptr.vf = vp9_mse8x8;
       break;
     case BLOCK_16X8:
       v_fn_ptr.vf = vp9_mse16x8;
       break;
     case BLOCK_8X16:
       v_fn_ptr.vf = vp9_mse8x16;
       break;
     default:
       v_fn_ptr.vf = vp9_mse16x16;
       break;
   }
   // Set up pointers for this macro block recon buffer
   xd->plane[0].pre[0].buf = recon_buffer->y_buffer + recon_yoffset;
   // Initial step/diamond search centred on best mv
   tmp_mv.as_int = 0;
   ref_mv_full.as_mv.col = ref_mv->as_mv.col >> 3;
   ref_mv_full.as_mv.row = ref_mv->as_mv.row >> 3;
   tmp_err = cpi->diamond_search_sad(x, &ref_mv_full, &tmp_mv, step_param,
                                     x->sadperbit16, &num00, &v_fn_ptr,
                                     x->nmvjointcost,
                                     x->mvcost, ref_mv);
   if (tmp_err < INT_MAX - new_mv_mode_penalty)
     tmp_err += new_mv_mode_penalty;
   if (tmp_err < *best_motion_err) {
     *best_motion_err = tmp_err;
     best_mv->row = tmp_mv.as_mv.row;
     best_mv->col = tmp_mv.as_mv.col;
   }
   // Further step/diamond searches as necessary
   n = num00;
   num00 = 0;
   while (n < further_steps) {
     n++;
     if (num00) {
       num00--;
     } else {
       tmp_err = cpi->diamond_search_sad(x, &ref_mv_full, &tmp_mv,
                                         step_param + n, x->sadperbit16,
                                         &num00, &v_fn_ptr,
                                         x->nmvjointcost,
                                         x->mvcost, ref_mv);
       if (tmp_err < INT_MAX - new_mv_mode_penalty)
         tmp_err += new_mv_mode_penalty;
       if (tmp_err < *best_motion_err) {
         *best_motion_err = tmp_err;
         best_mv->row = tmp_mv.as_mv.row;
         best_mv->col = tmp_mv.as_mv.col;
       }
     }
   }
 }
 void vp9_first_pass(VP9_COMP *cpi) {
   int mb_row, mb_col;
   MACROBLOCK *const x = &cpi->mb;
   VP9_COMMON *const cm = &cpi->common;
   MACROBLOCKD *const xd = &x->e_mbd;
   TileInfo tile;
   struct macroblock_plane *const p = x->plane;
   struct macroblockd_plane *const pd = xd->plane;
   PICK_MODE_CONTEXT *ctx = &x->sb64_context;
   int i;
   int recon_yoffset, recon_uvoffset;
   const int lst_yv12_idx = cm->ref_frame_map[cpi->lst_fb_idx];
   const int gld_yv12_idx = cm->ref_frame_map[cpi->gld_fb_idx];
   YV12_BUFFER_CONFIG *const lst_yv12 = &cm->yv12_fb[lst_yv12_idx];
   YV12_BUFFER_CONFIG *const gld_yv12 = &cm->yv12_fb[gld_yv12_idx];
   YV12_BUFFER_CONFIG *const new_yv12 = get_frame_new_buffer(cm);
   const int recon_y_stride = lst_yv12->y_stride;
   const int recon_uv_stride = lst_yv12->uv_stride;
   int64_t intra_error = 0;
   int64_t coded_error = 0;
   int64_t sr_coded_error = 0;
   int sum_mvr = 0, sum_mvc = 0;
   int sum_mvr_abs = 0, sum_mvc_abs = 0;
   int sum_mvrs = 0, sum_mvcs = 0;
   int mvcount = 0;
   int intercount = 0;
   int second_ref_count = 0;
   int intrapenalty = 256;
   int neutral_count = 0;
   int new_mv_count = 0;
   int sum_in_vectors = 0;
   uint32_t lastmv_as_int = 0;
   int_mv zero_ref_mv;
   zero_ref_mv.as_int = 0;
   vp9_clear_system_state();  // __asm emms;
   vp9_setup_src_planes(x, cpi->Source, 0, 0);
   setup_pre_planes(xd, 0, lst_yv12, 0, 0, NULL);
   setup_dst_planes(xd, new_yv12, 0, 0);
   xd->mi_8x8 = cm->mi_grid_visible;
   // required for vp9_frame_init_quantizer
   xd->mi_8x8[0] = cm->mi;
   setup_block_dptrs(&x->e_mbd, cm->subsampling_x, cm->subsampling_y);
   vp9_frame_init_quantizer(cpi);
   for (i = 0; i < MAX_MB_PLANE; ++i) {
     p[i].coeff = ctx->coeff_pbuf[i][1];
     pd[i].qcoeff = ctx->qcoeff_pbuf[i][1];
     pd[i].dqcoeff = ctx->dqcoeff_pbuf[i][1];
     pd[i].eobs = ctx->eobs_pbuf[i][1];
   }
   x->skip_recode = 0;
   // Initialise the MV cost table to the defaults
   // if( cm->current_video_frame == 0)
   // if ( 0 )
   {
     vp9_init_mv_probs(cm);
     vp9_initialize_rd_consts(cpi);
   }
   // tiling is ignored in the first pass
   vp9_tile_init(&tile, cm, 0, 0);
   // for each macroblock row in image
   for (mb_row = 0; mb_row < cm->mb_rows; mb_row++) {
     int_mv best_ref_mv;
     best_ref_mv.as_int = 0;
     // reset above block coeffs
     xd->up_available = (mb_row != 0);
     recon_yoffset = (mb_row * recon_y_stride * 16);
     recon_uvoffset = (mb_row * recon_uv_stride * 8);
     // Set up limit values for motion vectors to prevent them extending
     // outside the UMV borders
     x->mv_row_min = -((mb_row * 16) + BORDER_MV_PIXELS_B16);
     x->mv_row_max = ((cm->mb_rows - 1 - mb_row) * 16)
                     + BORDER_MV_PIXELS_B16;
     // for each macroblock col in image
     for (mb_col = 0; mb_col < cm->mb_cols; mb_col++) {
       int this_error;
       int gf_motion_error = INT_MAX;
       int use_dc_pred = (mb_col || mb_row) && (!mb_col || !mb_row);
       double error_weight;
       vp9_clear_system_state();  // __asm emms;
       error_weight = 1.0;  // avoid uninitialized warnings
       xd->plane[0].dst.buf = new_yv12->y_buffer + recon_yoffset;
       xd->plane[1].dst.buf = new_yv12->u_buffer + recon_uvoffset;
       xd->plane[2].dst.buf = new_yv12->v_buffer + recon_uvoffset;
       xd->left_available = (mb_col != 0);
       if (mb_col * 2 + 1 < cm->mi_cols) {
         if (mb_row * 2 + 1 < cm->mi_rows) {
           xd->mi_8x8[0]->mbmi.sb_type = BLOCK_16X16;
         } else {
           xd->mi_8x8[0]->mbmi.sb_type = BLOCK_16X8;
         }
       } else {
         if (mb_row * 2 + 1 < cm->mi_rows) {
           xd->mi_8x8[0]->mbmi.sb_type = BLOCK_8X16;
         } else {
           xd->mi_8x8[0]->mbmi.sb_type = BLOCK_8X8;
         }
       }
       xd->mi_8x8[0]->mbmi.ref_frame[0] = INTRA_FRAME;
       set_mi_row_col(xd, &tile,
                      mb_row << 1,
                      num_8x8_blocks_high_lookup[xd->mi_8x8[0]->mbmi.sb_type],
                      mb_col << 1,
                      num_8x8_blocks_wide_lookup[xd->mi_8x8[0]->mbmi.sb_type],
                      cm->mi_rows, cm->mi_cols);
       if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
         int energy = vp9_block_energy(cpi, x, xd->mi_8x8[0]->mbmi.sb_type);
         error_weight = vp9_vaq_inv_q_ratio(energy);
       }
       // do intra 16x16 prediction
       this_error = vp9_encode_intra(x, use_dc_pred);
       if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
         vp9_clear_system_state();  // __asm emms;
         this_error *= error_weight;
       }
       // intrapenalty below deals with situations where the intra and inter
       // error scores are very low (eg a plain black frame).
       // We do not have special cases in first pass for 0,0 and nearest etc so
       // all inter modes carry an overhead cost estimate for the mv.
       // When the error score is very low this causes us to pick all or lots of
       // INTRA modes and throw lots of key frames.
       // This penalty adds a cost matching that of a 0,0 mv to the intra case.
       this_error += intrapenalty;
       // Cumulative intra error total
       intra_error += (int64_t)this_error;
       // Set up limit values for motion vectors to prevent them extending
       // outside the UMV borders.
       x->mv_col_min = -((mb_col * 16) + BORDER_MV_PIXELS_B16);
       x->mv_col_max = ((cm->mb_cols - 1 - mb_col) * 16)
                       + BORDER_MV_PIXELS_B16;
       // Other than for the first frame do a motion search
       if (cm->current_video_frame > 0) {
         int tmp_err;
         int motion_error = INT_MAX;
         int_mv mv, tmp_mv;
         // Simple 0,0 motion with no mv overhead
         zz_motion_search(cpi, x, lst_yv12, &motion_error, recon_yoffset);
         mv.as_int = tmp_mv.as_int = 0;
         // Test last reference frame using the previous best mv as the
         // starting point (best reference) for the search
         first_pass_motion_search(cpi, x, &best_ref_mv,
                                  &mv.as_mv, lst_yv12,
                                  &motion_error, recon_yoffset);
         if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
           vp9_clear_system_state();  // __asm emms;
           motion_error *= error_weight;
         }
         // If the current best reference mv is not centered on 0,0 then do a 0,0
         // based search as well.
         if (best_ref_mv.as_int) {
           tmp_err = INT_MAX;
           first_pass_motion_search(cpi, x, &zero_ref_mv, &tmp_mv.as_mv,
                                    lst_yv12, &tmp_err, recon_yoffset);
           if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
             vp9_clear_system_state();  // __asm emms;
             tmp_err *= error_weight;
           }
           if (tmp_err < motion_error) {
             motion_error = tmp_err;
             mv.as_int = tmp_mv.as_int;
           }
         }
         // Experimental search in an older reference frame
         if (cm->current_video_frame > 1) {
           // Simple 0,0 motion with no mv overhead
           zz_motion_search(cpi, x, gld_yv12,
                            &gf_motion_error, recon_yoffset);
           first_pass_motion_search(cpi, x, &zero_ref_mv,
                                    &tmp_mv.as_mv, gld_yv12,
                                    &gf_motion_error, recon_yoffset);
           if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
             vp9_clear_system_state();  // __asm emms;
             gf_motion_error *= error_weight;
           }
           if ((gf_motion_error < motion_error) &&
               (gf_motion_error < this_error)) {
             second_ref_count++;
           }
           // Reset to last frame as reference buffer
           xd->plane[0].pre[0].buf = lst_yv12->y_buffer + recon_yoffset;
           xd->plane[1].pre[0].buf = lst_yv12->u_buffer + recon_uvoffset;
           xd->plane[2].pre[0].buf = lst_yv12->v_buffer + recon_uvoffset;
           // In accumulating a score for the older reference frame
           // take the best of the motion predicted score and
           // the intra coded error (just as will be done for)
           // accumulation of "coded_error" for the last frame.
           if (gf_motion_error < this_error)
             sr_coded_error += gf_motion_error;
           else
             sr_coded_error += this_error;
         } else {
           sr_coded_error += motion_error;
         }
         /* Intra assumed best */
         best_ref_mv.as_int = 0;
         if (motion_error <= this_error) {
           // Keep a count of cases where the inter and intra were
           // very close and very low. This helps with scene cut
           // detection for example in cropped clips with black bars
           // at the sides or top and bottom.
           if ((((this_error - intrapenalty) * 9) <=
                (motion_error * 10)) &&
               (this_error < (2 * intrapenalty))) {
             neutral_count++;
           }
           mv.as_mv.row *= 8;
           mv.as_mv.col *= 8;
           this_error = motion_error;
           vp9_set_mbmode_and_mvs(x, NEWMV, &mv);
           xd->mi_8x8[0]->mbmi.tx_size = TX_4X4;
           xd->mi_8x8[0]->mbmi.ref_frame[0] = LAST_FRAME;
           xd->mi_8x8[0]->mbmi.ref_frame[1] = NONE;
           vp9_build_inter_predictors_sby(xd, mb_row << 1,
                                          mb_col << 1,
                                          xd->mi_8x8[0]->mbmi.sb_type);
           vp9_encode_sby(x, xd->mi_8x8[0]->mbmi.sb_type);
           sum_mvr += mv.as_mv.row;
           sum_mvr_abs += abs(mv.as_mv.row);
           sum_mvc += mv.as_mv.col;
           sum_mvc_abs += abs(mv.as_mv.col);
           sum_mvrs += mv.as_mv.row * mv.as_mv.row;
           sum_mvcs += mv.as_mv.col * mv.as_mv.col;
           intercount++;
           best_ref_mv.as_int = mv.as_int;
           // Was the vector non-zero
           if (mv.as_int) {
             mvcount++;
             // Was it different from the last non zero vector
             if (mv.as_int != lastmv_as_int)
               new_mv_count++;
             lastmv_as_int = mv.as_int;
             // Does the Row vector point inwards or outwards
             if (mb_row < cm->mb_rows / 2) {
               if (mv.as_mv.row > 0)
                 sum_in_vectors--;
               else if (mv.as_mv.row < 0)
                 sum_in_vectors++;
             } else if (mb_row > cm->mb_rows / 2) {
               if (mv.as_mv.row > 0)
                 sum_in_vectors++;
               else if (mv.as_mv.row < 0)
                 sum_in_vectors--;
             }
             // Does the Row vector point inwards or outwards
             if (mb_col < cm->mb_cols / 2) {
               if (mv.as_mv.col > 0)
                 sum_in_vectors--;
               else if (mv.as_mv.col < 0)
                 sum_in_vectors++;
             } else if (mb_col > cm->mb_cols / 2) {
               if (mv.as_mv.col > 0)
                 sum_in_vectors++;
               else if (mv.as_mv.col < 0)
                 sum_in_vectors--;
             }
           }
         }
       } else {
         sr_coded_error += (int64_t)this_error;
       }
       coded_error += (int64_t)this_error;
       // adjust to the next column of macroblocks
       x->plane[0].src.buf += 16;
       x->plane[1].src.buf += 8;
       x->plane[2].src.buf += 8;
       recon_yoffset += 16;
       recon_uvoffset += 8;
     }
     // adjust to the next row of mbs
     x->plane[0].src.buf += 16 * x->plane[0].src.stride - 16 * cm->mb_cols;
     x->plane[1].src.buf += 8 * x->plane[1].src.stride - 8 * cm->mb_cols;
     x->plane[2].src.buf += 8 * x->plane[1].src.stride - 8 * cm->mb_cols;
     vp9_clear_system_state();  // __asm emms;
   }
   vp9_clear_system_state();  // __asm emms;
   {
     double weight = 0.0;
     FIRSTPASS_STATS fps;
     fps.frame      = cm->current_video_frame;
     fps.intra_error = (double)(intra_error >> 8);
     fps.coded_error = (double)(coded_error >> 8);
     fps.sr_coded_error = (double)(sr_coded_error >> 8);
     weight = simple_weight(cpi->Source);
     if (weight < 0.1)
       weight = 0.1;
     fps.ssim_weighted_pred_err = fps.coded_error * weight;
     fps.pcnt_inter  = 0.0;
     fps.pcnt_motion = 0.0;
     fps.MVr        = 0.0;
     fps.mvr_abs     = 0.0;
     fps.MVc        = 0.0;
     fps.mvc_abs     = 0.0;
     fps.MVrv       = 0.0;
     fps.MVcv       = 0.0;
     fps.mv_in_out_count  = 0.0;
     fps.new_mv_count = 0.0;
     fps.count      = 1.0;
     fps.pcnt_inter   = 1.0 * (double)intercount / cm->MBs;
     fps.pcnt_second_ref = 1.0 * (double)second_ref_count / cm->MBs;
     fps.pcnt_neutral = 1.0 * (double)neutral_count / cm->MBs;
     if (mvcount > 0) {
       fps.MVr = (double)sum_mvr / (double)mvcount;
       fps.mvr_abs = (double)sum_mvr_abs / (double)mvcount;
       fps.MVc = (double)sum_mvc / (double)mvcount;
       fps.mvc_abs = (double)sum_mvc_abs / (double)mvcount;
       fps.MVrv = ((double)sum_mvrs - (fps.MVr * fps.MVr / (double)mvcount)) /
                  (double)mvcount;
       fps.MVcv = ((double)sum_mvcs - (fps.MVc * fps.MVc / (double)mvcount)) /
                  (double)mvcount;
       fps.mv_in_out_count = (double)sum_in_vectors / (double)(mvcount * 2);
       fps.new_mv_count = new_mv_count;
       fps.pcnt_motion = 1.0 * (double)mvcount / cpi->common.MBs;
     }
     // TODO(paulwilkins):  Handle the case when duration is set to 0, or
     // something less than the full time between subsequent values of
     // cpi->source_time_stamp.
     fps.duration = (double)(cpi->source->ts_end
                             - cpi->source->ts_start);
     // don't want to do output stats with a stack variable!
     cpi->twopass.this_frame_stats = fps;
     output_stats(cpi, cpi->output_pkt_list, &cpi->twopass.this_frame_stats);
     accumulate_stats(&cpi->twopass.total_stats, &fps);
   }
   // Copy the previous Last Frame back into gf and and arf buffers if
   // the prediction is good enough... but also dont allow it to lag too far
   if ((cpi->twopass.sr_update_lag > 3) ||
       ((cm->current_video_frame > 0) &&
        (cpi->twopass.this_frame_stats.pcnt_inter > 0.20) &&
        ((cpi->twopass.this_frame_stats.intra_error /
          DOUBLE_DIVIDE_CHECK(cpi->twopass.this_frame_stats.coded_error)) >
 .0))) {
     vp8_yv12_copy_frame(lst_yv12, gld_yv12);
     cpi->twopass.sr_update_lag = 1;
   } else {
     cpi->twopass.sr_update_lag++;
   }
   // swap frame pointers so last frame refers to the frame we just compressed
   swap_yv12(lst_yv12, new_yv12);
   vp9_extend_frame_borders(lst_yv12, cm->subsampling_x, cm->subsampling_y);
   // Special case for the first frame. Copy into the GF buffer as a second
   // reference.
   if (cm->current_video_frame == 0)
     vp8_yv12_copy_frame(lst_yv12, gld_yv12);
   // use this to see what the first pass reconstruction looks like
   if (0) {
     char filename[512];
     FILE *recon_file;
     snprintf(filename, sizeof(filename), "enc%04d.yuv",
              (int)cm->current_video_frame);
     if (cm->current_video_frame == 0)
       recon_file = fopen(filename, "wb");
     else
       recon_file = fopen(filename, "ab");
     (void)fwrite(lst_yv12->buffer_alloc, lst_yv12->frame_size, 1, recon_file);
     fclose(recon_file);
   }
   cm->current_video_frame++;
 }
 // Estimate a cost per mb attributable to overheads such as the coding of
 // modes and motion vectors.
 // Currently simplistic in its assumptions for testing.
 //
 static double bitcost(double prob) {
   return -(log(prob) / log(2.0));
 }
 static int64_t estimate_modemvcost(VP9_COMP *cpi,
                                      FIRSTPASS_STATS *fpstats) {
 #if 0
   int mv_cost;
   int mode_cost;
   double av_pct_inter = fpstats->pcnt_inter / fpstats->count;
   double av_pct_motion = fpstats->pcnt_motion / fpstats->count;
   double av_intra = (1.0 - av_pct_inter);
   double zz_cost;
   double motion_cost;
   double intra_cost;
   zz_cost = bitcost(av_pct_inter - av_pct_motion);
   motion_cost = bitcost(av_pct_motion);
   intra_cost = bitcost(av_intra);
   // Estimate of extra bits per mv overhead for mbs
   // << 9 is the normalization to the (bits * 512) used in vp9_bits_per_mb
   mv_cost = ((int)(fpstats->new_mv_count / fpstats->count) * 8) << 9;
   // Crude estimate of overhead cost from modes
   // << 9 is the normalization to (bits * 512) used in vp9_bits_per_mb
   mode_cost =
     (int)((((av_pct_inter - av_pct_motion) * zz_cost) +
            (av_pct_motion * motion_cost) +
            (av_intra * intra_cost)) * cpi->common.MBs) << 9;
   // return mv_cost + mode_cost;
   // TODO(paulwilkins): Fix overhead costs for extended Q range.
 #endif
   return 0;
 }
 static double calc_correction_factor(double err_per_mb,
                                      double err_divisor,
                                      double pt_low,
                                      double pt_high,
                                      int q) {
   const double error_term = err_per_mb / err_divisor;
   // Adjustment based on actual quantizer to power term.
   const double power_term = MIN(vp9_convert_qindex_to_q(q) * 0.01 + pt_low,
                                 pt_high);
   // Calculate correction factor
   if (power_term < 1.0)
     assert(error_term >= 0.0);
   return fclamp(pow(error_term, power_term), 0.05, 5.0);
 }
 // Given a current maxQ value sets a range for future values.
 // PGW TODO..
 // This code removes direct dependency on QIndex to determine the range
 // (now uses the actual quantizer) but has not been tuned.
 static void adjust_maxq_qrange(VP9_COMP *cpi) {
   int i;
   // Set the max corresponding to cpi->avg_q * 2.0
   double q = cpi->avg_q * 2.0;
   cpi->twopass.maxq_max_limit = cpi->worst_quality;
   for (i = cpi->best_quality; i <= cpi->worst_quality; i++) {
     cpi->twopass.maxq_max_limit = i;
     if (vp9_convert_qindex_to_q(i) >= q)
       break;
   }
   // Set the min corresponding to cpi->avg_q * 0.5
   q = cpi->avg_q * 0.5;
   cpi->twopass.maxq_min_limit = cpi->best_quality;
   for (i = cpi->worst_quality; i >= cpi->best_quality; i--) {
     cpi->twopass.maxq_min_limit = i;
     if (vp9_convert_qindex_to_q(i) <= q)
       break;
   }
 }
 static int estimate_max_q(VP9_COMP *cpi,
                           FIRSTPASS_STATS *fpstats,
                           int section_target_bandwitdh) {
   int q;
   int num_mbs = cpi->common.MBs;
   int target_norm_bits_per_mb;
   double section_err = fpstats->coded_error / fpstats->count;
   double sr_correction;
   double err_per_mb = section_err / num_mbs;
   double err_correction_factor;
   double speed_correction = 1.0;
   if (section_target_bandwitdh <= 0)
     return cpi->twopass.maxq_max_limit;          // Highest value allowed
   target_norm_bits_per_mb = section_target_bandwitdh < (1 << 20)
                               ? (512 * section_target_bandwitdh) / num_mbs
                               : 512 * (section_target_bandwitdh / num_mbs);
   // Look at the drop in prediction quality between the last frame
   // and the GF buffer (which contained an older frame).
   if (fpstats->sr_coded_error > fpstats->coded_error) {
     double sr_err_diff = (fpstats->sr_coded_error - fpstats->coded_error) /
                              (fpstats->count * cpi->common.MBs);
     sr_correction = fclamp(pow(sr_err_diff / 32.0, 0.25), 0.75, 1.25);
   } else {
     sr_correction = 0.75;
   }
   // Calculate a corrective factor based on a rolling ratio of bits spent
   // vs target bits
   if (cpi->rolling_target_bits > 0 &&
       cpi->active_worst_quality < cpi->worst_quality) {
     double rolling_ratio = (double)cpi->rolling_actual_bits /
                                (double)cpi->rolling_target_bits;
     if (rolling_ratio < 0.95)
       cpi->twopass.est_max_qcorrection_factor -= 0.005;
     else if (rolling_ratio > 1.05)
       cpi->twopass.est_max_qcorrection_factor += 0.005;
     cpi->twopass.est_max_qcorrection_factor = fclamp(
         cpi->twopass.est_max_qcorrection_factor, 0.1, 10.0);
   }
   // Corrections for higher compression speed settings
   // (reduced compression expected)
   // FIXME(jimbankoski): Once we settle on vp9 speed features we need to
   // change this code.
   if (cpi->compressor_speed == 1)
     speed_correction = cpi->oxcf.cpu_used <= 5 ?
 .04 + (/*cpi->oxcf.cpu_used*/0 * 0.04) :
 .25;
   // Try and pick a max Q that will be high enough to encode the
   // content at the given rate.
   for (q = cpi->twopass.maxq_min_limit; q < cpi->twopass.maxq_max_limit; q++) {
     int bits_per_mb_at_this_q;
     err_correction_factor = calc_correction_factor(err_per_mb,
                                                    ERR_DIVISOR, 0.4, 0.90, q) *
                                 sr_correction * speed_correction *
                                 cpi->twopass.est_max_qcorrection_factor;
     bits_per_mb_at_this_q = vp9_bits_per_mb(INTER_FRAME, q,
                                             err_correction_factor);
     if (bits_per_mb_at_this_q <= target_norm_bits_per_mb)
       break;
   }
   // Restriction on active max q for constrained quality mode.
   if (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY &&
       q < cpi->cq_target_quality)
     q = cpi->cq_target_quality;
   // Adjust maxq_min_limit and maxq_max_limit limits based on
   // average q observed in clip for non kf/gf/arf frames
   // Give average a chance to settle though.
   // PGW TODO.. This code is broken for the extended Q range
   if (cpi->ni_frames > ((int)cpi->twopass.total_stats.count >> 8) &&
       cpi->ni_frames > 25)
     adjust_maxq_qrange(cpi);
   return q;
 }
 // For cq mode estimate a cq level that matches the observed
 // complexity and data rate.
 static int estimate_cq(VP9_COMP *cpi,
                        FIRSTPASS_STATS *fpstats,
                        int section_target_bandwitdh) {
   int q;
   int num_mbs = cpi->common.MBs;
   int target_norm_bits_per_mb;
   double section_err = (fpstats->coded_error / fpstats->count);
   double err_per_mb = section_err / num_mbs;
   double err_correction_factor;
   double sr_err_diff;
   double sr_correction;
   double speed_correction = 1.0;
   double clip_iiratio;
   double clip_iifactor;
   target_norm_bits_per_mb = (section_target_bandwitdh < (1 << 20))
                             ? (512 * section_target_bandwitdh) / num_mbs
                             : 512 * (section_target_bandwitdh / num_mbs);
   // Corrections for higher compression speed settings
   // (reduced compression expected)
   if (cpi->compressor_speed == 1) {
     if (cpi->oxcf.cpu_used <= 5)
       speed_correction = 1.04 + (/*cpi->oxcf.cpu_used*/ 0 * 0.04);
     else
       speed_correction = 1.25;
   }
   // Look at the drop in prediction quality between the last frame
   // and the GF buffer (which contained an older frame).
   if (fpstats->sr_coded_error > fpstats->coded_error) {
     sr_err_diff =
       (fpstats->sr_coded_error - fpstats->coded_error) /
       (fpstats->count * cpi->common.MBs);
     sr_correction = (sr_err_diff / 32.0);
     sr_correction = pow(sr_correction, 0.25);
     if (sr_correction < 0.75)
       sr_correction = 0.75;
     else if (sr_correction > 1.25)
       sr_correction = 1.25;
   } else {
     sr_correction = 0.75;
   }
   // II ratio correction factor for clip as a whole
   clip_iiratio = cpi->twopass.total_stats.intra_error /
                  DOUBLE_DIVIDE_CHECK(cpi->twopass.total_stats.coded_error);
   clip_iifactor = 1.0 - ((clip_iiratio - 10.0) * 0.025);
   if (clip_iifactor < 0.80)
     clip_iifactor = 0.80;
   // Try and pick a Q that can encode the content at the given rate.
   for (q = 0; q < MAXQ; q++) {
     int bits_per_mb_at_this_q;
     // Error per MB based correction factor
     err_correction_factor =
       calc_correction_factor(err_per_mb, 100.0, 0.4, 0.90, q) *
       sr_correction * speed_correction * clip_iifactor;
     bits_per_mb_at_this_q =
       vp9_bits_per_mb(INTER_FRAME, q, err_correction_factor);
     if (bits_per_mb_at_this_q <= target_norm_bits_per_mb)
       break;
   }
   // Clip value to range "best allowed to (worst allowed - 1)"
   q = select_cq_level(q);
   if (q >= cpi->worst_quality)
     q = cpi->worst_quality - 1;
   if (q < cpi->best_quality)
     q = cpi->best_quality;
   return q;
 }
 extern void vp9_new_framerate(VP9_COMP *cpi, double framerate);
 void vp9_init_second_pass(VP9_COMP *cpi) {
   FIRSTPASS_STATS this_frame;
   FIRSTPASS_STATS *start_pos;
   double lower_bounds_min_rate = FRAME_OVERHEAD_BITS * cpi->oxcf.framerate;
   double two_pass_min_rate = (double)(cpi->oxcf.target_bandwidth *
                                       cpi->oxcf.two_pass_vbrmin_section / 100);
   if (two_pass_min_rate < lower_bounds_min_rate)
     two_pass_min_rate = lower_bounds_min_rate;
   zero_stats(&cpi->twopass.total_stats);
   zero_stats(&cpi->twopass.total_left_stats);
   if (!cpi->twopass.stats_in_end)
     return;
   cpi->twopass.total_stats = *cpi->twopass.stats_in_end;
   cpi->twopass.total_left_stats = cpi->twopass.total_stats;
   // each frame can have a different duration, as the frame rate in the source
   // isn't guaranteed to be constant.   The frame rate prior to the first frame
   // encoded in the second pass is a guess.  However the sum duration is not.
   // Its calculated based on the actual durations of all frames from the first
   // pass.
   vp9_new_framerate(cpi, 10000000.0 * cpi->twopass.total_stats.count /
                        cpi->twopass.total_stats.duration);
   cpi->output_framerate = cpi->oxcf.framerate;
   cpi->twopass.bits_left = (int64_t)(cpi->twopass.total_stats.duration *
                                      cpi->oxcf.target_bandwidth / 10000000.0);
   cpi->twopass.bits_left -= (int64_t)(cpi->twopass.total_stats.duration *
                                       two_pass_min_rate / 10000000.0);
   // Calculate a minimum intra value to be used in determining the IIratio
   // scores used in the second pass. We have this minimum to make sure
   // that clips that are static but "low complexity" in the intra domain
   // are still boosted appropriately for KF/GF/ARF
   cpi->twopass.kf_intra_err_min = KF_MB_INTRA_MIN * cpi->common.MBs;
   cpi->twopass.gf_intra_err_min = GF_MB_INTRA_MIN * cpi->common.MBs;
   // This variable monitors how far behind the second ref update is lagging
   cpi->twopass.sr_update_lag = 1;
   // Scan the first pass file and calculate an average Intra / Inter error score
   // ratio for the sequence.
   {
     double sum_iiratio = 0.0;
     double IIRatio;
     start_pos = cpi->twopass.stats_in;  // Note the starting "file" position.
     while (input_stats(cpi, &this_frame) != EOF) {
       IIRatio = this_frame.intra_error
                 / DOUBLE_DIVIDE_CHECK(this_frame.coded_error);
       IIRatio = (IIRatio < 1.0) ? 1.0 : (IIRatio > 20.0) ? 20.0 : IIRatio;
       sum_iiratio += IIRatio;
     }
     cpi->twopass.avg_iiratio = sum_iiratio /
         DOUBLE_DIVIDE_CHECK((double)cpi->twopass.total_stats.count);
     // Reset file position
     reset_fpf_position(cpi, start_pos);
   }
   // Scan the first pass file and calculate a modified total error based upon
   // the bias/power function used to allocate bits.
   {
     start_pos = cpi->twopass.stats_in;  // Note starting "file" position
     cpi->twopass.modified_error_total = 0.0;
     cpi->twopass.modified_error_used = 0.0;
     while (input_stats(cpi, &this_frame) != EOF) {
       cpi->twopass.modified_error_total +=
           calculate_modified_err(cpi, &this_frame);
     }
     cpi->twopass.modified_error_left = cpi->twopass.modified_error_total;
     reset_fpf_position(cpi, start_pos);  // Reset file position
   }
 }
 void vp9_end_second_pass(VP9_COMP *cpi) {
 }
 // This function gives and estimate of how badly we believe
 // the prediction quality is decaying from frame to frame.
 static double get_prediction_decay_rate(VP9_COMP *cpi,
                                         FIRSTPASS_STATS *next_frame) {
   double prediction_decay_rate;
   double second_ref_decay;
   double mb_sr_err_diff;
   // Initial basis is the % mbs inter coded
   prediction_decay_rate = next_frame->pcnt_inter;
   // Look at the observed drop in prediction quality between the last frame
   // and the GF buffer (which contains an older frame).
   mb_sr_err_diff = (next_frame->sr_coded_error - next_frame->coded_error) /
                    cpi->common.MBs;
   if (mb_sr_err_diff <= 512.0) {
     second_ref_decay = 1.0 - (mb_sr_err_diff / 512.0);
     second_ref_decay = pow(second_ref_decay, 0.5);
     if (second_ref_decay < 0.85)
       second_ref_decay = 0.85;
     else if (second_ref_decay > 1.0)
       second_ref_decay = 1.0;
   } else {
     second_ref_decay = 0.85;
   }
   if (second_ref_decay < prediction_decay_rate)
     prediction_decay_rate = second_ref_decay;
   return prediction_decay_rate;
 }
 // Function to test for a condition where a complex transition is followed
 // by a static section. For example in slide shows where there is a fade
 // between slides. This is to help with more optimal kf and gf positioning.
 static int detect_transition_to_still(
   VP9_COMP *cpi,
   int frame_interval,
   int still_interval,
   double loop_decay_rate,
   double last_decay_rate) {
   int trans_to_still = 0;
   // Break clause to detect very still sections after motion
   // For example a static image after a fade or other transition
   // instead of a clean scene cut.
   if (frame_interval > MIN_GF_INTERVAL &&
       loop_decay_rate >= 0.999 &&
       last_decay_rate < 0.9) {
     int j;
     FIRSTPASS_STATS *position = cpi->twopass.stats_in;
     FIRSTPASS_STATS tmp_next_frame;
     double zz_inter;
     // Look ahead a few frames to see if static condition
     // persists...
     for (j = 0; j < still_interval; j++) {
       if (EOF == input_stats(cpi, &tmp_next_frame))
         break;
       zz_inter =
         (tmp_next_frame.pcnt_inter - tmp_next_frame.pcnt_motion);
       if (zz_inter < 0.999)
         break;
     }
     // Reset file position
     reset_fpf_position(cpi, position);
     // Only if it does do we signal a transition to still
     if (j == still_interval)
       trans_to_still = 1;
   }
   return trans_to_still;
 }
 // This function detects a flash through the high relative pcnt_second_ref
 // score in the frame following a flash frame. The offset passed in should
 // reflect this
 static int detect_flash(VP9_COMP *cpi, int offset) {
   FIRSTPASS_STATS next_frame;
   int flash_detected = 0;
   // Read the frame data.
   // The return is FALSE (no flash detected) if not a valid frame
   if (read_frame_stats(cpi, &next_frame, offset) != EOF) {
     // What we are looking for here is a situation where there is a
     // brief break in prediction (such as a flash) but subsequent frames
     // are reasonably well predicted by an earlier (pre flash) frame.
     // The recovery after a flash is indicated by a high pcnt_second_ref
     // comapred to pcnt_inter.
     if (next_frame.pcnt_second_ref > next_frame.pcnt_inter &&
         next_frame.pcnt_second_ref >= 0.5)
       flash_detected = 1;
   }
   return flash_detected;
 }
 // Update the motion related elements to the GF arf boost calculation
 static void accumulate_frame_motion_stats(
   FIRSTPASS_STATS *this_frame,
   double *this_frame_mv_in_out,
   double *mv_in_out_accumulator,
   double *abs_mv_in_out_accumulator,
   double *mv_ratio_accumulator) {
   // double this_frame_mv_in_out;
   double this_frame_mvr_ratio;
   double this_frame_mvc_ratio;
   double motion_pct;
   // Accumulate motion stats.
   motion_pct = this_frame->pcnt_motion;
   // Accumulate Motion In/Out of frame stats
   *this_frame_mv_in_out = this_frame->mv_in_out_count * motion_pct;
   *mv_in_out_accumulator += this_frame->mv_in_out_count * motion_pct;
   *abs_mv_in_out_accumulator +=
     fabs(this_frame->mv_in_out_count * motion_pct);
   // Accumulate a measure of how uniform (or conversely how random)
   // the motion field is. (A ratio of absmv / mv)
   if (motion_pct > 0.05) {
     this_frame_mvr_ratio = fabs(this_frame->mvr_abs) /
                            DOUBLE_DIVIDE_CHECK(fabs(this_frame->MVr));
     this_frame_mvc_ratio = fabs(this_frame->mvc_abs) /
                            DOUBLE_DIVIDE_CHECK(fabs(this_frame->MVc));
     *mv_ratio_accumulator +=
       (this_frame_mvr_ratio < this_frame->mvr_abs)
       ? (this_frame_mvr_ratio * motion_pct)
       : this_frame->mvr_abs * motion_pct;
     *mv_ratio_accumulator +=
       (this_frame_mvc_ratio < this_frame->mvc_abs)
       ? (this_frame_mvc_ratio * motion_pct)
       : this_frame->mvc_abs * motion_pct;
   }
 }
 // Calculate a baseline boost number for the current frame.
 static double calc_frame_boost(
   VP9_COMP *cpi,
   FIRSTPASS_STATS *this_frame,
   double this_frame_mv_in_out) {
   double frame_boost;
   // Underlying boost factor is based on inter intra error ratio
   if (this_frame->intra_error > cpi->twopass.gf_intra_err_min)
     frame_boost = (IIFACTOR * this_frame->intra_error /
                    DOUBLE_DIVIDE_CHECK(this_frame->coded_error));
   else
     frame_boost = (IIFACTOR * cpi->twopass.gf_intra_err_min /
                    DOUBLE_DIVIDE_CHECK(this_frame->coded_error));
   // Increase boost for frames where new data coming into frame
   // (eg zoom out). Slightly reduce boost if there is a net balance
   // of motion out of the frame (zoom in).
   // The range for this_frame_mv_in_out is -1.0 to +1.0
   if (this_frame_mv_in_out > 0.0)
     frame_boost += frame_boost * (this_frame_mv_in_out * 2.0);
   // In extreme case boost is halved
   else
     frame_boost += frame_boost * (this_frame_mv_in_out / 2.0);
   // Clip to maximum
   if (frame_boost > GF_RMAX)
     frame_boost = GF_RMAX;
   return frame_boost;
 }
 static int calc_arf_boost(VP9_COMP *cpi, int offset,
                           int f_frames, int b_frames,
                           int *f_boost, int *b_boost) {
   FIRSTPASS_STATS this_frame;
   int i;
   double boost_score = 0.0;
   double mv_ratio_accumulator = 0.0;
   double decay_accumulator = 1.0;
   double this_frame_mv_in_out = 0.0;
   double mv_in_out_accumulator = 0.0;
   double abs_mv_in_out_accumulator = 0.0;
   int arf_boost;
   int flash_detected = 0;
   // Search forward from the proposed arf/next gf position
   for (i = 0; i < f_frames; i++) {
     if (read_frame_stats(cpi, &this_frame, (i + offset)) == EOF)
       break;
     // Update the motion related elements to the boost calculation
     accumulate_frame_motion_stats(&this_frame,
                                   &this_frame_mv_in_out, &mv_in_out_accumulator,
                                   &abs_mv_in_out_accumulator,
                                   &mv_ratio_accumulator);
     // We want to discount the flash frame itself and the recovery
     // frame that follows as both will have poor scores.
     flash_detected = detect_flash(cpi, (i + offset)) ||
                      detect_flash(cpi, (i + offset + 1));
     // Cumulative effect of prediction quality decay
     if (!flash_detected) {
       decay_accumulator *= get_prediction_decay_rate(cpi, &this_frame);
       decay_accumulator = decay_accumulator < MIN_DECAY_FACTOR
                           ? MIN_DECAY_FACTOR : decay_accumulator;
     }
     boost_score += (decay_accumulator *
                     calc_frame_boost(cpi, &this_frame, this_frame_mv_in_out));
   }
   *f_boost = (int)boost_score;
   // Reset for backward looking loop
   boost_score = 0.0;
   mv_ratio_accumulator = 0.0;
   decay_accumulator = 1.0;
   this_frame_mv_in_out = 0.0;
   mv_in_out_accumulator = 0.0;
   abs_mv_in_out_accumulator = 0.0;
   // Search backward towards last gf position
   for (i = -1; i >= -b_frames; i--) {
     if (read_frame_stats(cpi, &this_frame, (i + offset)) == EOF)
       break;
     // Update the motion related elements to the boost calculation
     accumulate_frame_motion_stats(&this_frame,
                                   &this_frame_mv_in_out, &mv_in_out_accumulator,
                                   &abs_mv_in_out_accumulator,
                                   &mv_ratio_accumulator);
     // We want to discount the the flash frame itself and the recovery
     // frame that follows as both will have poor scores.
     flash_detected = detect_flash(cpi, (i + offset)) ||
                      detect_flash(cpi, (i + offset + 1));
     // Cumulative effect of prediction quality decay
     if (!flash_detected) {
       decay_accumulator *= get_prediction_decay_rate(cpi, &this_frame);
       decay_accumulator = decay_accumulator < MIN_DECAY_FACTOR
                               ? MIN_DECAY_FACTOR : decay_accumulator;
     }
     boost_score += (decay_accumulator *
                     calc_frame_boost(cpi, &this_frame, this_frame_mv_in_out));
   }
   *b_boost = (int)boost_score;
   arf_boost = (*f_boost + *b_boost);
   if (arf_boost < ((b_frames + f_frames) * 20))
     arf_boost = ((b_frames + f_frames) * 20);
   return arf_boost;
 }
 #if CONFIG_MULTIPLE_ARF
 // Work out the frame coding order for a GF or an ARF group.
 // The current implementation codes frames in their natural order for a
 // GF group, and inserts additional ARFs into an ARF group using a
 // binary split approach.
 // NOTE: this function is currently implemented recursively.
 static void schedule_frames(VP9_COMP *cpi, const int start, const int end,
                             const int arf_idx, const int gf_or_arf_group,
                             const int level) {
   int i, abs_end, half_range;
   int *cfo = cpi->frame_coding_order;
   int idx = cpi->new_frame_coding_order_period;
   // If (end < 0) an ARF should be coded at position (-end).
   assert(start >= 0);
   // printf("start:%d end:%d\n", start, end);
   // GF Group: code frames in logical order.
   if (gf_or_arf_group == 0) {
     assert(end >= start);
     for (i = start; i <= end; ++i) {
       cfo[idx] = i;
       cpi->arf_buffer_idx[idx] = arf_idx;
       cpi->arf_weight[idx] = -1;
       ++idx;
     }
     cpi->new_frame_coding_order_period = idx;
     return;
   }
   // ARF Group: work out the ARF schedule.
   // Mark ARF frames as negative.
   if (end < 0) {
     // printf("start:%d end:%d\n", -end, -end);
     // ARF frame is at the end of the range.
     cfo[idx] = end;
     // What ARF buffer does this ARF use as predictor.
     cpi->arf_buffer_idx[idx] = (arf_idx > 2) ? (arf_idx - 1) : 2;
     cpi->arf_weight[idx] = level;
     ++idx;
     abs_end = -end;
   } else {
     abs_end = end;
   }
   half_range = (abs_end - start) >> 1;
   // ARFs may not be adjacent, they must be separated by at least
   // MIN_GF_INTERVAL non-ARF frames.
   if ((start + MIN_GF_INTERVAL) >= (abs_end - MIN_GF_INTERVAL)) {
     // printf("start:%d end:%d\n", start, abs_end);
     // Update the coding order and active ARF.
     for (i = start; i <= abs_end; ++i) {
       cfo[idx] = i;
       cpi->arf_buffer_idx[idx] = arf_idx;
       cpi->arf_weight[idx] = -1;
       ++idx;
     }
     cpi->new_frame_coding_order_period = idx;
   } else {
     // Place a new ARF at the mid-point of the range.
     cpi->new_frame_coding_order_period = idx;
     schedule_frames(cpi, start, -(start + half_range), arf_idx + 1,
                     gf_or_arf_group, level + 1);
     schedule_frames(cpi, start + half_range + 1, abs_end, arf_idx,
                     gf_or_arf_group, level + 1);
   }
 }
 #define FIXED_ARF_GROUP_SIZE 16
 void define_fixed_arf_period(VP9_COMP *cpi) {
   int i;
   int max_level = INT_MIN;
   assert(cpi->multi_arf_enabled);
   assert(cpi->oxcf.lag_in_frames >= FIXED_ARF_GROUP_SIZE);
   // Save the weight of the last frame in the sequence before next
   // sequence pattern overwrites it.
   cpi->this_frame_weight = cpi->arf_weight[cpi->sequence_number];
   assert(cpi->this_frame_weight >= 0);
   // Initialize frame coding order variables.
   cpi->new_frame_coding_order_period = 0;
   cpi->next_frame_in_order = 0;
   cpi->arf_buffered = 0;
   vp9_zero(cpi->frame_coding_order);
   vp9_zero(cpi->arf_buffer_idx);
   vpx_memset(cpi->arf_weight, -1, sizeof(cpi->arf_weight));
   if (cpi->twopass.frames_to_key <= (FIXED_ARF_GROUP_SIZE + 8)) {
     // Setup a GF group close to the keyframe.
     cpi->source_alt_ref_pending = 0;
     cpi->baseline_gf_interval = cpi->twopass.frames_to_key;
     schedule_frames(cpi, 0, (cpi->baseline_gf_interval - 1), 2, 0, 0);
   } else {
     // Setup a fixed period ARF group.
     cpi->source_alt_ref_pending = 1;
     cpi->baseline_gf_interval = FIXED_ARF_GROUP_SIZE;
     schedule_frames(cpi, 0, -(cpi->baseline_gf_interval - 1), 2, 1, 0);
   }
   // Replace level indicator of -1 with correct level.
   for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
     if (cpi->arf_weight[i] > max_level) {
       max_level = cpi->arf_weight[i];
     }
   }
   ++max_level;
   for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
     if (cpi->arf_weight[i] == -1) {
       cpi->arf_weight[i] = max_level;
     }
   }
   cpi->max_arf_level = max_level;
 #if 0
   printf("\nSchedule: ");
   for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
     printf("%4d ", cpi->frame_coding_order[i]);
   }
   printf("\n");
   printf("ARFref:   ");
   for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
     printf("%4d ", cpi->arf_buffer_idx[i]);
   }
   printf("\n");
   printf("Weight:   ");
   for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
     printf("%4d ", cpi->arf_weight[i]);
   }
   printf("\n");
 #endif
 }
 #endif
 // Analyse and define a gf/arf group.
 static void define_gf_group(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
   FIRSTPASS_STATS next_frame = { 0 };
   FIRSTPASS_STATS *start_pos;
   int i;
   double boost_score = 0.0;
   double old_boost_score = 0.0;
   double gf_group_err = 0.0;
   double gf_first_frame_err = 0.0;
   double mod_frame_err = 0.0;
   double mv_ratio_accumulator = 0.0;
   double decay_accumulator = 1.0;
   double zero_motion_accumulator = 1.0;
   double loop_decay_rate = 1.00;          // Starting decay rate
   double last_loop_decay_rate = 1.00;
   double this_frame_mv_in_out = 0.0;
   double mv_in_out_accumulator = 0.0;
   double abs_mv_in_out_accumulator = 0.0;
   double mv_ratio_accumulator_thresh;
   int max_bits = frame_max_bits(cpi);     // Max for a single frame
   unsigned int allow_alt_ref =
     cpi->oxcf.play_alternate && cpi->oxcf.lag_in_frames;
   int f_boost = 0;
   int b_boost = 0;
   int flash_detected;
   int active_max_gf_interval;
   cpi->twopass.gf_group_bits = 0;
   vp9_clear_system_state();  // __asm emms;
   start_pos = cpi->twopass.stats_in;
   // Load stats for the current frame.
   mod_frame_err = calculate_modified_err(cpi, this_frame);
   // Note the error of the frame at the start of the group (this will be
   // the GF frame error if we code a normal gf
   gf_first_frame_err = mod_frame_err;
   // Special treatment if the current frame is a key frame (which is also
   // a gf). If it is then its error score (and hence bit allocation) need
   // to be subtracted out from the calculation for the GF group
   if (cpi->common.frame_type == KEY_FRAME)
     gf_group_err -= gf_first_frame_err;
   // Motion breakout threshold for loop below depends on image size.
   mv_ratio_accumulator_thresh = (cpi->common.width + cpi->common.height) / 10.0;
   // Work out a maximum interval for the GF.
   // If the image appears completely static we can extend beyond this.
   // The value chosen depends on the active Q range. At low Q we have
   // bits to spare and are better with a smaller interval and smaller boost.
   // At high Q when there are few bits to spare we are better with a longer
   // interval to spread the cost of the GF.
   active_max_gf_interval =
 + ((int)vp9_convert_qindex_to_q(cpi->active_worst_quality) >> 5);
   if (active_max_gf_interval > cpi->max_gf_interval)
     active_max_gf_interval = cpi->max_gf_interval;
   i = 0;
   while (((i < cpi->twopass.static_scene_max_gf_interval) ||
           ((cpi->twopass.frames_to_key - i) < MIN_GF_INTERVAL)) &&
          (i < cpi->twopass.frames_to_key)) {
     i++;    // Increment the loop counter
     // Accumulate error score of frames in this gf group
     mod_frame_err = calculate_modified_err(cpi, this_frame);
     gf_group_err += mod_frame_err;
     if (EOF == input_stats(cpi, &next_frame))
       break;
     // Test for the case where there is a brief flash but the prediction
     // quality back to an earlier frame is then restored.
     flash_detected = detect_flash(cpi, 0);
     // Update the motion related elements to the boost calculation
     accumulate_frame_motion_stats(&next_frame,
                                   &this_frame_mv_in_out, &mv_in_out_accumulator,
                                   &abs_mv_in_out_accumulator,
                                   &mv_ratio_accumulator);
     // Cumulative effect of prediction quality decay
     if (!flash_detected) {
       last_loop_decay_rate = loop_decay_rate;
       loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
       decay_accumulator = decay_accumulator * loop_decay_rate;
       // Monitor for static sections.
       if ((next_frame.pcnt_inter - next_frame.pcnt_motion) <
           zero_motion_accumulator) {
         zero_motion_accumulator =
           (next_frame.pcnt_inter - next_frame.pcnt_motion);
       }
       // Break clause to detect very still sections after motion
       // (for example a static image after a fade or other transition).
       if (detect_transition_to_still(cpi, i, 5, loop_decay_rate,
                                      last_loop_decay_rate)) {
         allow_alt_ref = 0;
         break;
       }
     }
     // Calculate a boost number for this frame
     boost_score +=
       (decay_accumulator *
        calc_frame_boost(cpi, &next_frame, this_frame_mv_in_out));
     // Break out conditions.
     if (
       // Break at cpi->max_gf_interval unless almost totally static
       (i >= active_max_gf_interval && (zero_motion_accumulator < 0.995)) ||
       (
         // Don't break out with a very short interval
         (i > MIN_GF_INTERVAL) &&
         // Don't break out very close to a key frame
         ((cpi->twopass.frames_to_key - i) >= MIN_GF_INTERVAL) &&
         ((boost_score > 125.0) || (next_frame.pcnt_inter < 0.75)) &&
         (!flash_detected) &&
         ((mv_ratio_accumulator > mv_ratio_accumulator_thresh) ||
          (abs_mv_in_out_accumulator > 3.0) ||
          (mv_in_out_accumulator < -2.0) ||
          ((boost_score - old_boost_score) < IIFACTOR)))) {
       boost_score = old_boost_score;
       break;
     }
     *this_frame = next_frame;
     old_boost_score = boost_score;
   }
   cpi->gf_zeromotion_pct = (int)(zero_motion_accumulator * 1000.0);
   // Don't allow a gf too near the next kf
   if ((cpi->twopass.frames_to_key - i) < MIN_GF_INTERVAL) {
     while (i < cpi->twopass.frames_to_key) {
       i++;
       if (EOF == input_stats(cpi, this_frame))
         break;
       if (i < cpi->twopass.frames_to_key) {
         mod_frame_err = calculate_modified_err(cpi, this_frame);
         gf_group_err += mod_frame_err;
       }
     }
   }
   // Set the interval until the next gf or arf.
   cpi->baseline_gf_interval = i;
 #if CONFIG_MULTIPLE_ARF
   if (cpi->multi_arf_enabled) {
     // Initialize frame coding order variables.
     cpi->new_frame_coding_order_period = 0;
     cpi->next_frame_in_order = 0;
     cpi->arf_buffered = 0;
     vp9_zero(cpi->frame_coding_order);
     vp9_zero(cpi->arf_buffer_idx);
     vpx_memset(cpi->arf_weight, -1, sizeof(cpi->arf_weight));
   }
 #endif
   // Should we use the alternate reference frame
   if (allow_alt_ref &&
       (i < cpi->oxcf.lag_in_frames) &&
       (i >= MIN_GF_INTERVAL) &&
       // dont use ARF very near next kf
       (i <= (cpi->twopass.frames_to_key - MIN_GF_INTERVAL)) &&
       ((next_frame.pcnt_inter > 0.75) ||
        (next_frame.pcnt_second_ref > 0.5)) &&
       ((mv_in_out_accumulator / (double)i > -0.2) ||
        (mv_in_out_accumulator > -2.0)) &&
       (boost_score > 100)) {
     // Alternative boost calculation for alt ref
     cpi->gfu_boost = calc_arf_boost(cpi, 0, (i - 1), (i - 1), &f_boost,
                                     &b_boost);
     cpi->source_alt_ref_pending = 1;
 #if CONFIG_MULTIPLE_ARF
     // Set the ARF schedule.
     if (cpi->multi_arf_enabled) {
       schedule_frames(cpi, 0, -(cpi->baseline_gf_interval - 1), 2, 1, 0);
     }
 #endif
   } else {
     cpi->gfu_boost = (int)boost_score;
     cpi->source_alt_ref_pending = 0;
 #if CONFIG_MULTIPLE_ARF
     // Set the GF schedule.
     if (cpi->multi_arf_enabled) {
       schedule_frames(cpi, 0, cpi->baseline_gf_interval - 1, 2, 0, 0);
       assert(cpi->new_frame_coding_order_period == cpi->baseline_gf_interval);
     }
 #endif
   }
 #if CONFIG_MULTIPLE_ARF
   if (cpi->multi_arf_enabled && (cpi->common.frame_type != KEY_FRAME)) {
     int max_level = INT_MIN;
     // Replace level indicator of -1 with correct level.
     for (i = 0; i < cpi->frame_coding_order_period; ++i) {
       if (cpi->arf_weight[i] > max_level) {
         max_level = cpi->arf_weight[i];
       }
     }
     ++max_level;
     for (i = 0; i < cpi->frame_coding_order_period; ++i) {
       if (cpi->arf_weight[i] == -1) {
         cpi->arf_weight[i] = max_level;
       }
     }
     cpi->max_arf_level = max_level;
   }
 #if 0
   if (cpi->multi_arf_enabled) {
     printf("\nSchedule: ");
     for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
       printf("%4d ", cpi->frame_coding_order[i]);
     }
     printf("\n");
     printf("ARFref:   ");
     for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
       printf("%4d ", cpi->arf_buffer_idx[i]);
     }
     printf("\n");
     printf("Weight:   ");
     for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
       printf("%4d ", cpi->arf_weight[i]);
     }
     printf("\n");
   }
 #endif
 #endif
   // Now decide how many bits should be allocated to the GF group as  a
   // proportion of those remaining in the kf group.
   // The final key frame group in the clip is treated as a special case
   // where cpi->twopass.kf_group_bits is tied to cpi->twopass.bits_left.
   // This is also important for short clips where there may only be one
   // key frame.
   if (cpi->twopass.frames_to_key >= (int)(cpi->twopass.total_stats.count -
                                           cpi->common.current_video_frame)) {
     cpi->twopass.kf_group_bits =
       (cpi->twopass.bits_left > 0) ? cpi->twopass.bits_left : 0;
   }
   // Calculate the bits to be allocated to the group as a whole
   if ((cpi->twopass.kf_group_bits > 0) &&
       (cpi->twopass.kf_group_error_left > 0)) {
     cpi->twopass.gf_group_bits =
       (int64_t)(cpi->twopass.kf_group_bits *
                 (gf_group_err / cpi->twopass.kf_group_error_left));
   } else {
     cpi->twopass.gf_group_bits = 0;
   }
   cpi->twopass.gf_group_bits =
     (cpi->twopass.gf_group_bits < 0)
     ? 0
     : (cpi->twopass.gf_group_bits > cpi->twopass.kf_group_bits)
     ? cpi->twopass.kf_group_bits : cpi->twopass.gf_group_bits;
   // Clip cpi->twopass.gf_group_bits based on user supplied data rate
   // variability limit (cpi->oxcf.two_pass_vbrmax_section)
   if (cpi->twopass.gf_group_bits >
       (int64_t)max_bits * cpi->baseline_gf_interval)
     cpi->twopass.gf_group_bits = (int64_t)max_bits * cpi->baseline_gf_interval;
   // Reset the file position
   reset_fpf_position(cpi, start_pos);
   // Update the record of error used so far (only done once per gf group)
   cpi->twopass.modified_error_used += gf_group_err;
   // Assign  bits to the arf or gf.
   for (i = 0;
       i <= (cpi->source_alt_ref_pending && cpi->common.frame_type != KEY_FRAME);
       ++i) {
     int allocation_chunks;
     int q = cpi->oxcf.fixed_q < 0 ? cpi->last_q[INTER_FRAME]
                                   : cpi->oxcf.fixed_q;
     int gf_bits;
     int boost = (cpi->gfu_boost * vp9_gfboost_qadjust(q)) / 100;
     // Set max and minimum boost and hence minimum allocation
     boost = clamp(boost, 125, (cpi->baseline_gf_interval + 1) * 200);
     if (cpi->source_alt_ref_pending && i == 0)
       allocation_chunks = ((cpi->baseline_gf_interval + 1) * 100) + boost;
     else
       allocation_chunks = (cpi->baseline_gf_interval * 100) + (boost - 100);
     // Prevent overflow
     if (boost > 1023) {
       int divisor = boost >> 10;
       boost /= divisor;
       allocation_chunks /= divisor;
     }
     // Calculate the number of bits to be spent on the gf or arf based on
     // the boost number
     gf_bits = (int)((double)boost * (cpi->twopass.gf_group_bits /
                                        (double)allocation_chunks));
     // If the frame that is to be boosted is simpler than the average for
     // the gf/arf group then use an alternative calculation
     // based on the error score of the frame itself
     if (mod_frame_err < gf_group_err / (double)cpi->baseline_gf_interval) {
       double alt_gf_grp_bits =
         (double)cpi->twopass.kf_group_bits  *
         (mod_frame_err * (double)cpi->baseline_gf_interval) /
         DOUBLE_DIVIDE_CHECK(cpi->twopass.kf_group_error_left);
       int alt_gf_bits = (int)((double)boost * (alt_gf_grp_bits /
                                            (double)allocation_chunks));
       if (gf_bits > alt_gf_bits)
         gf_bits = alt_gf_bits;
     } else {
       // If it is harder than other frames in the group make sure it at
       // least receives an allocation in keeping with its relative error
       // score, otherwise it may be worse off than an "un-boosted" frame.
       int alt_gf_bits = (int)((double)cpi->twopass.kf_group_bits *
                         mod_frame_err /
                         DOUBLE_DIVIDE_CHECK(cpi->twopass.kf_group_error_left));
       if (alt_gf_bits > gf_bits)
         gf_bits = alt_gf_bits;
     }
     // Dont allow a negative value for gf_bits
     if (gf_bits < 0)
       gf_bits = 0;
     // Add in minimum for a frame
     gf_bits += cpi->min_frame_bandwidth;
     if (i == 0) {
       cpi->twopass.gf_bits = gf_bits;
     }
     if (i == 1 || (!cpi->source_alt_ref_pending
         && (cpi->common.frame_type != KEY_FRAME))) {
       // Per frame bit target for this frame
       cpi->per_frame_bandwidth = gf_bits;
     }
   }
   {
     // Adjust KF group bits and error remaining
     cpi->twopass.kf_group_error_left -= (int64_t)gf_group_err;
     cpi->twopass.kf_group_bits -= cpi->twopass.gf_group_bits;
     if (cpi->twopass.kf_group_bits < 0)
       cpi->twopass.kf_group_bits = 0;
     // Note the error score left in the remaining frames of the group.
     // For normal GFs we want to remove the error score for the first frame
     // of the group (except in Key frame case where this has already
     // happened)
     if (!cpi->source_alt_ref_pending && cpi->common.frame_type != KEY_FRAME)
       cpi->twopass.gf_group_error_left = (int64_t)(gf_group_err
                                                    - gf_first_frame_err);
     else
       cpi->twopass.gf_group_error_left = (int64_t)gf_group_err;
     cpi->twopass.gf_group_bits -= cpi->twopass.gf_bits
         - cpi->min_frame_bandwidth;
     if (cpi->twopass.gf_group_bits < 0)
       cpi->twopass.gf_group_bits = 0;
     // This condition could fail if there are two kfs very close together
     // despite (MIN_GF_INTERVAL) and would cause a divide by 0 in the
     // calculation of alt_extra_bits.
     if (cpi->baseline_gf_interval >= 3) {
       const int boost = cpi->source_alt_ref_pending ? b_boost : cpi->gfu_boost;
       if (boost >= 150) {
         int alt_extra_bits;
         int pct_extra = (boost - 100) / 50;
         pct_extra = (pct_extra > 20) ? 20 : pct_extra;
         alt_extra_bits = (int)((cpi->twopass.gf_group_bits * pct_extra) / 100);
         cpi->twopass.gf_group_bits -= alt_extra_bits;
       }
     }
   }
   if (cpi->common.frame_type != KEY_FRAME) {
     FIRSTPASS_STATS sectionstats;
     zero_stats(&sectionstats);
     reset_fpf_position(cpi, start_pos);
     for (i = 0; i < cpi->baseline_gf_interval; i++) {
       input_stats(cpi, &next_frame);
       accumulate_stats(&sectionstats, &next_frame);
     }
     avg_stats(&sectionstats);
     cpi->twopass.section_intra_rating = (int)
       (sectionstats.intra_error /
       DOUBLE_DIVIDE_CHECK(sectionstats.coded_error));
     reset_fpf_position(cpi, start_pos);
   }
 }
 // Allocate bits to a normal frame that is neither a gf an arf or a key frame.
 static void assign_std_frame_bits(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
   int target_frame_size;
   double modified_err;
   double err_fraction;
   // Max for a single frame.
   int max_bits = frame_max_bits(cpi);
   // Calculate modified prediction error used in bit allocation.
   modified_err = calculate_modified_err(cpi, this_frame);
   if (cpi->twopass.gf_group_error_left > 0)
     // What portion of the remaining GF group error is used by this frame.
     err_fraction = modified_err / cpi->twopass.gf_group_error_left;
   else
     err_fraction = 0.0;
   // How many of those bits available for allocation should we give it?
   target_frame_size = (int)((double)cpi->twopass.gf_group_bits * err_fraction);
   // Clip target size to 0 - max_bits (or cpi->twopass.gf_group_bits) at
   // the top end.
   if (target_frame_size < 0) {
     target_frame_size = 0;
   } else {
     if (target_frame_size > max_bits)
       target_frame_size = max_bits;
     if (target_frame_size > cpi->twopass.gf_group_bits)
       target_frame_size = (int)cpi->twopass.gf_group_bits;
   }
   // Adjust error and bits remaining.
   cpi->twopass.gf_group_error_left -= (int64_t)modified_err;
   cpi->twopass.gf_group_bits -= target_frame_size;
   if (cpi->twopass.gf_group_bits < 0)
     cpi->twopass.gf_group_bits = 0;
   // Add in the minimum number of bits that is set aside for every frame.
   target_frame_size += cpi->min_frame_bandwidth;
   // Per frame bit target for this frame.
   cpi->per_frame_bandwidth = target_frame_size;
 }
 // Make a damped adjustment to the active max q.
 static int adjust_active_maxq(int old_maxqi, int new_maxqi) {
   int i;
   const double old_q = vp9_convert_qindex_to_q(old_maxqi);
   const double new_q = vp9_convert_qindex_to_q(new_maxqi);
   const double target_q = ((old_q * 7.0) + new_q) / 8.0;
   if (target_q > old_q) {
     for (i = old_maxqi; i <= new_maxqi; i++)
       if (vp9_convert_qindex_to_q(i) >= target_q)
         return i;
   } else {
     for (i = old_maxqi; i >= new_maxqi; i--)
       if (vp9_convert_qindex_to_q(i) <= target_q)
         return i;
   }
   return new_maxqi;
 }
 void vp9_second_pass(VP9_COMP *cpi) {
   int tmp_q;
   int frames_left = (int)(cpi->twopass.total_stats.count -
                           cpi->common.current_video_frame);
   FIRSTPASS_STATS this_frame;
   FIRSTPASS_STATS this_frame_copy;
   double this_frame_intra_error;
   double this_frame_coded_error;
   if (!cpi->twopass.stats_in)
     return;
   vp9_clear_system_state();
   if (cpi->oxcf.end_usage == USAGE_CONSTANT_QUALITY) {
     cpi->active_worst_quality = cpi->oxcf.cq_level;
   } else {
     // Special case code for first frame.
     if (cpi->common.current_video_frame == 0) {
       int section_target_bandwidth =
           (int)(cpi->twopass.bits_left / frames_left);
       cpi->twopass.est_max_qcorrection_factor = 1.0;
       // Set a cq_level in constrained quality mode.
       // Commenting this code out for now since it does not seem to be
       // working well.
       /*
       if (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) {
         int est_cq = estimate_cq(cpi, &cpi->twopass.total_left_stats,
            section_target_bandwidth);
         if (est_cq > cpi->cq_target_quality)
           cpi->cq_target_quality = est_cq;
         else
           cpi->cq_target_quality = cpi->oxcf.cq_level;
       }
       */
       // guess at maxq needed in 2nd pass
       cpi->twopass.maxq_max_limit = cpi->worst_quality;
       cpi->twopass.maxq_min_limit = cpi->best_quality;
       tmp_q = estimate_max_q(cpi, &cpi->twopass.total_left_stats,
                              section_target_bandwidth);
       cpi->active_worst_quality = tmp_q;
       cpi->ni_av_qi = tmp_q;
       cpi->avg_q = vp9_convert_qindex_to_q(tmp_q);
       // Limit the maxq value returned subsequently.
       // This increases the risk of overspend or underspend if the initial
       // estimate for the clip is bad, but helps prevent excessive
       // variation in Q, especially near the end of a clip
       // where for example a small overspend may cause Q to crash
       adjust_maxq_qrange(cpi);
     }
     // The last few frames of a clip almost always have to few or too many
     // bits and for the sake of over exact rate control we dont want to make
     // radical adjustments to the allowed quantizer range just to use up a
     // few surplus bits or get beneath the target rate.
     else if ((cpi->common.current_video_frame <
               (((unsigned int)cpi->twopass.total_stats.count * 255) >> 8)) &&
              ((cpi->common.current_video_frame + cpi->baseline_gf_interval) <
               (unsigned int)cpi->twopass.total_stats.count)) {
       int section_target_bandwidth =
           (int)(cpi->twopass.bits_left / frames_left);
       if (frames_left < 1)
         frames_left = 1;
       tmp_q = estimate_max_q(
           cpi,
           &cpi->twopass.total_left_stats,
           section_target_bandwidth);
       // Make a damped adjustment to active max Q
       cpi->active_worst_quality =
           adjust_active_maxq(cpi->active_worst_quality, tmp_q);
     }
   }
   vp9_zero(this_frame);
   if (EOF == input_stats(cpi, &this_frame))
     return;
   this_frame_intra_error = this_frame.intra_error;
   this_frame_coded_error = this_frame.coded_error;
   // keyframe and section processing !
   if (cpi->twopass.frames_to_key == 0) {
     // Define next KF group and assign bits to it
     this_frame_copy = this_frame;
     find_next_key_frame(cpi, &this_frame_copy);
   }
   // Is this a GF / ARF (Note that a KF is always also a GF)
   if (cpi->frames_till_gf_update_due == 0) {
     // Define next gf group and assign bits to it
     this_frame_copy = this_frame;
     cpi->gf_zeromotion_pct = 0;
 #if CONFIG_MULTIPLE_ARF
     if (cpi->multi_arf_enabled) {
       define_fixed_arf_period(cpi);
     } else {
 #endif
       define_gf_group(cpi, &this_frame_copy);
 #if CONFIG_MULTIPLE_ARF
     }
 #endif
     if (cpi->gf_zeromotion_pct > 995) {
       // As long as max_thresh for encode breakout is small enough, it is ok
       // to enable it for no-show frame, i.e. set enable_encode_breakout to 2.
       if (!cpi->common.show_frame)
         cpi->enable_encode_breakout = 0;
       else
         cpi->enable_encode_breakout = 2;
     }
     // If we are going to code an altref frame at the end of the group
     // and the current frame is not a key frame....
     // If the previous group used an arf this frame has already benefited
     // from that arf boost and it should not be given extra bits
     // If the previous group was NOT coded using arf we may want to apply
     // some boost to this GF as well
     if (cpi->source_alt_ref_pending && (cpi->common.frame_type != KEY_FRAME)) {
       // Assign a standard frames worth of bits from those allocated
       // to the GF group
       int bak = cpi->per_frame_bandwidth;
       this_frame_copy = this_frame;
       assign_std_frame_bits(cpi, &this_frame_copy);
       cpi->per_frame_bandwidth = bak;
     }
   } else {
     // Otherwise this is an ordinary frame
     // Assign bits from those allocated to the GF group
     this_frame_copy =  this_frame;
     assign_std_frame_bits(cpi, &this_frame_copy);
   }
   // Keep a globally available copy of this and the next frame's iiratio.
   cpi->twopass.this_iiratio = (int)(this_frame_intra_error /
                               DOUBLE_DIVIDE_CHECK(this_frame_coded_error));
   {
     FIRSTPASS_STATS next_frame;
     if (lookup_next_frame_stats(cpi, &next_frame) != EOF) {
       cpi->twopass.next_iiratio = (int)(next_frame.intra_error /
                                   DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
     }
   }
   // Set nominal per second bandwidth for this frame
   cpi->target_bandwidth = (int)(cpi->per_frame_bandwidth
                                 * cpi->output_framerate);
   if (cpi->target_bandwidth < 0)
     cpi->target_bandwidth = 0;
   cpi->twopass.frames_to_key--;
   // Update the total stats remaining structure
   subtract_stats(&cpi->twopass.total_left_stats, &this_frame);
 }
 static int test_candidate_kf(VP9_COMP *cpi,
                              FIRSTPASS_STATS *last_frame,
                              FIRSTPASS_STATS *this_frame,
                              FIRSTPASS_STATS *next_frame) {
   int is_viable_kf = 0;
   // Does the frame satisfy the primary criteria of a key frame
   //      If so, then examine how well it predicts subsequent frames
   if ((this_frame->pcnt_second_ref < 0.10) &&
       (next_frame->pcnt_second_ref < 0.10) &&
       ((this_frame->pcnt_inter < 0.05) ||
        (((this_frame->pcnt_inter - this_frame->pcnt_neutral) < .35) &&
         ((this_frame->intra_error /
           DOUBLE_DIVIDE_CHECK(this_frame->coded_error)) < 2.5) &&
         ((fabs(last_frame->coded_error - this_frame->coded_error) /
               DOUBLE_DIVIDE_CHECK(this_frame->coded_error) >
           .40) ||
          (fabs(last_frame->intra_error - this_frame->intra_error) /
               DOUBLE_DIVIDE_CHECK(this_frame->intra_error) >
           .40) ||
          ((next_frame->intra_error /
            DOUBLE_DIVIDE_CHECK(next_frame->coded_error)) > 3.5))))) {
     int i;
     FIRSTPASS_STATS *start_pos;
     FIRSTPASS_STATS local_next_frame;
     double boost_score = 0.0;
     double old_boost_score = 0.0;
     double decay_accumulator = 1.0;
     double next_iiratio;
     local_next_frame = *next_frame;
     // Note the starting file position so we can reset to it
     start_pos = cpi->twopass.stats_in;
     // Examine how well the key frame predicts subsequent frames
     for (i = 0; i < 16; i++) {
       next_iiratio = (IIKFACTOR1 * local_next_frame.intra_error /
                       DOUBLE_DIVIDE_CHECK(local_next_frame.coded_error));
       if (next_iiratio > RMAX)
         next_iiratio = RMAX;
       // Cumulative effect of decay in prediction quality
       if (local_next_frame.pcnt_inter > 0.85)
         decay_accumulator = decay_accumulator * local_next_frame.pcnt_inter;
       else
         decay_accumulator =
             decay_accumulator * ((0.85 + local_next_frame.pcnt_inter) / 2.0);
       // decay_accumulator = decay_accumulator * local_next_frame.pcnt_inter;
       // Keep a running total
       boost_score += (decay_accumulator * next_iiratio);
       // Test various breakout clauses
       if ((local_next_frame.pcnt_inter < 0.05) ||
           (next_iiratio < 1.5) ||
           (((local_next_frame.pcnt_inter -
              local_next_frame.pcnt_neutral) < 0.20) &&
            (next_iiratio < 3.0)) ||
           ((boost_score - old_boost_score) < 3.0) ||
           (local_next_frame.intra_error < 200)
          ) {
         break;
       }
       old_boost_score = boost_score;
       // Get the next frame details
       if (EOF == input_stats(cpi, &local_next_frame))
         break;
     }
     // If there is tolerable prediction for at least the next 3 frames then
     // break out else discard this potential key frame and move on
     if (boost_score > 30.0 && (i > 3)) {
       is_viable_kf = 1;
     } else {
       // Reset the file position
       reset_fpf_position(cpi, start_pos);
       is_viable_kf = 0;
     }
   }
   return is_viable_kf;
 }
 static void find_next_key_frame(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
   int i, j;
   FIRSTPASS_STATS last_frame;
   FIRSTPASS_STATS first_frame;
   FIRSTPASS_STATS next_frame;
   FIRSTPASS_STATS *start_position;
   double decay_accumulator = 1.0;
   double zero_motion_accumulator = 1.0;
   double boost_score = 0;
   double loop_decay_rate;
   double kf_mod_err = 0.0;
   double kf_group_err = 0.0;
   double kf_group_intra_err = 0.0;
   double kf_group_coded_err = 0.0;
   double recent_loop_decay[8] = {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0};
   vp9_zero(next_frame);
   vp9_clear_system_state();  // __asm emms;
   start_position = cpi->twopass.stats_in;
   cpi->common.frame_type = KEY_FRAME;
   // is this a forced key frame by interval
   cpi->this_key_frame_forced = cpi->next_key_frame_forced;
   // Clear the alt ref active flag as this can never be active on a key frame
   cpi->source_alt_ref_active = 0;
   // Kf is always a gf so clear frames till next gf counter
   cpi->frames_till_gf_update_due = 0;
   cpi->twopass.frames_to_key = 1;
   // Take a copy of the initial frame details
   first_frame = *this_frame;
   cpi->twopass.kf_group_bits = 0;        // Total bits available to kf group
   cpi->twopass.kf_group_error_left = 0;  // Group modified error score.
   kf_mod_err = calculate_modified_err(cpi, this_frame);
   // find the next keyframe
   i = 0;
   while (cpi->twopass.stats_in < cpi->twopass.stats_in_end) {
     // Accumulate kf group error
     kf_group_err += calculate_modified_err(cpi, this_frame);
     // These figures keep intra and coded error counts for all frames including
     // key frames in the group. The effect of the key frame itself can be
     // subtracted out using the first_frame data collected above.
     kf_group_intra_err += this_frame->intra_error;
     kf_group_coded_err += this_frame->coded_error;
     // load a the next frame's stats
     last_frame = *this_frame;
     input_stats(cpi, this_frame);
     // Provided that we are not at the end of the file...
     if (cpi->oxcf.auto_key
         && lookup_next_frame_stats(cpi, &next_frame) != EOF) {
       // Normal scene cut check
       if (test_candidate_kf(cpi, &last_frame, this_frame, &next_frame))
         break;
       // How fast is prediction quality decaying
       loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
       // We want to know something about the recent past... rather than
       // as used elsewhere where we are concened with decay in prediction
       // quality since the last GF or KF.
       recent_loop_decay[i % 8] = loop_decay_rate;
       decay_accumulator = 1.0;
       for (j = 0; j < 8; j++)
         decay_accumulator *= recent_loop_decay[j];
       // Special check for transition or high motion followed by a
       // to a static scene.
       if (detect_transition_to_still(cpi, i, cpi->key_frame_frequency - i,
                                      loop_decay_rate, decay_accumulator))
         break;
       // Step on to the next frame
       cpi->twopass.frames_to_key++;
       // If we don't have a real key frame within the next two
       // forcekeyframeevery intervals then break out of the loop.
       if (cpi->twopass.frames_to_key >= 2 * (int)cpi->key_frame_frequency)
         break;
     } else {
       cpi->twopass.frames_to_key++;
     }
     i++;
   }
   // If there is a max kf interval set by the user we must obey it.
   // We already breakout of the loop above at 2x max.
   // This code centers the extra kf if the actual natural
   // interval is between 1x and 2x
   if (cpi->oxcf.auto_key
       && cpi->twopass.frames_to_key > (int)cpi->key_frame_frequency) {
     FIRSTPASS_STATS *current_pos = cpi->twopass.stats_in;
     FIRSTPASS_STATS tmp_frame;
     cpi->twopass.frames_to_key /= 2;
     // Copy first frame details
     tmp_frame = first_frame;
     // Reset to the start of the group
     reset_fpf_position(cpi, start_position);
     kf_group_err = 0;
     kf_group_intra_err = 0;
     kf_group_coded_err = 0;
     // Rescan to get the correct error data for the forced kf group
     for (i = 0; i < cpi->twopass.frames_to_key; i++) {
       // Accumulate kf group errors
       kf_group_err += calculate_modified_err(cpi, &tmp_frame);
       kf_group_intra_err += tmp_frame.intra_error;
       kf_group_coded_err += tmp_frame.coded_error;
       // Load a the next frame's stats
       input_stats(cpi, &tmp_frame);
     }
     // Reset to the start of the group
     reset_fpf_position(cpi, current_pos);
     cpi->next_key_frame_forced = 1;
   } else {
     cpi->next_key_frame_forced = 0;
   }
   // Special case for the last frame of the file
   if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end) {
     // Accumulate kf group error
     kf_group_err += calculate_modified_err(cpi, this_frame);
     // These figures keep intra and coded error counts for all frames including
     // key frames in the group. The effect of the key frame itself can be
     // subtracted out using the first_frame data collected above.
     kf_group_intra_err += this_frame->intra_error;
     kf_group_coded_err += this_frame->coded_error;
   }
   // Calculate the number of bits that should be assigned to the kf group.
   if ((cpi->twopass.bits_left > 0) &&
       (cpi->twopass.modified_error_left > 0.0)) {
     // Max for a single normal frame (not key frame)
     int max_bits = frame_max_bits(cpi);
     // Maximum bits for the kf group
     int64_t max_grp_bits;
     // Default allocation based on bits left and relative
     // complexity of the section
     cpi->twopass.kf_group_bits = (int64_t)(cpi->twopass.bits_left *
                                            (kf_group_err /
                                             cpi->twopass.modified_error_left));
     // Clip based on maximum per frame rate defined by the user.
     max_grp_bits = (int64_t)max_bits * (int64_t)cpi->twopass.frames_to_key;
     if (cpi->twopass.kf_group_bits > max_grp_bits)
       cpi->twopass.kf_group_bits = max_grp_bits;
   } else {
     cpi->twopass.kf_group_bits = 0;
   }
   // Reset the first pass file position
   reset_fpf_position(cpi, start_position);
   // Determine how big to make this keyframe based on how well the subsequent
   // frames use inter blocks.
   decay_accumulator = 1.0;
   boost_score = 0.0;
   loop_decay_rate = 1.00;       // Starting decay rate
   // Scan through the kf group collating various stats.
   for (i = 0; i < cpi->twopass.frames_to_key; i++) {
     double r;
     if (EOF == input_stats(cpi, &next_frame))
       break;
     // Monitor for static sections.
     if ((next_frame.pcnt_inter - next_frame.pcnt_motion) <
         zero_motion_accumulator) {
       zero_motion_accumulator =
         (next_frame.pcnt_inter - next_frame.pcnt_motion);
     }
     // For the first few frames collect data to decide kf boost.
     if (i <= (cpi->max_gf_interval * 2)) {
       if (next_frame.intra_error > cpi->twopass.kf_intra_err_min)
         r = (IIKFACTOR2 * next_frame.intra_error /
              DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
       else
         r = (IIKFACTOR2 * cpi->twopass.kf_intra_err_min /
              DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
       if (r > RMAX)
         r = RMAX;
       // How fast is prediction quality decaying
       if (!detect_flash(cpi, 0)) {
         loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
         decay_accumulator = decay_accumulator * loop_decay_rate;
         decay_accumulator = decay_accumulator < MIN_DECAY_FACTOR
                               ? MIN_DECAY_FACTOR : decay_accumulator;
       }
       boost_score += (decay_accumulator * r);
     }
   }
   {
     FIRSTPASS_STATS sectionstats;
     zero_stats(&sectionstats);
     reset_fpf_position(cpi, start_position);
     for (i = 0; i < cpi->twopass.frames_to_key; i++) {
       input_stats(cpi, &next_frame);
       accumulate_stats(&sectionstats, &next_frame);
     }
     avg_stats(&sectionstats);
     cpi->twopass.section_intra_rating = (int)
       (sectionstats.intra_error
       / DOUBLE_DIVIDE_CHECK(sectionstats.coded_error));
   }
   // Reset the first pass file position
   reset_fpf_position(cpi, start_position);
   // Work out how many bits to allocate for the key frame itself
   if (1) {
     int kf_boost = (int)boost_score;
     int allocation_chunks;
     int alt_kf_bits;
     if (kf_boost < (cpi->twopass.frames_to_key * 3))
       kf_boost = (cpi->twopass.frames_to_key * 3);
     if (kf_boost < 300)  // Min KF boost
       kf_boost = 300;
     // Make a note of baseline boost and the zero motion
     // accumulator value for use elsewhere.
     cpi->kf_boost = kf_boost;
     cpi->kf_zeromotion_pct = (int)(zero_motion_accumulator * 100.0);
     // We do three calculations for kf size.
     // The first is based on the error score for the whole kf group.
     // The second (optionaly) on the key frames own error if this is
     // smaller than the average for the group.
     // The final one insures that the frame receives at least the
     // allocation it would have received based on its own error score vs
     // the error score remaining
     // Special case if the sequence appears almost totaly static
     // In this case we want to spend almost all of the bits on the
     // key frame.
     // cpi->twopass.frames_to_key-1 because key frame itself is taken
     // care of by kf_boost.
     if (zero_motion_accumulator >= 0.99) {
       allocation_chunks =
         ((cpi->twopass.frames_to_key - 1) * 10) + kf_boost;
     } else {
       allocation_chunks =
         ((cpi->twopass.frames_to_key - 1) * 100) + kf_boost;
     }
     // Prevent overflow
     if (kf_boost > 1028) {
       int divisor = kf_boost >> 10;
       kf_boost /= divisor;
       allocation_chunks /= divisor;
     }
     cpi->twopass.kf_group_bits =
         (cpi->twopass.kf_group_bits < 0) ? 0 : cpi->twopass.kf_group_bits;
     // Calculate the number of bits to be spent on the key frame
     cpi->twopass.kf_bits =
         (int)((double)kf_boost *
               ((double)cpi->twopass.kf_group_bits / (double)allocation_chunks));
     // If the key frame is actually easier than the average for the
     // kf group (which does sometimes happen... eg a blank intro frame)
     // Then use an alternate calculation based on the kf error score
     // which should give a smaller key frame.
     if (kf_mod_err < kf_group_err / cpi->twopass.frames_to_key) {
       double  alt_kf_grp_bits =
         ((double)cpi->twopass.bits_left *
          (kf_mod_err * (double)cpi->twopass.frames_to_key) /
          DOUBLE_DIVIDE_CHECK(cpi->twopass.modified_error_left));
       alt_kf_bits = (int)((double)kf_boost *
                           (alt_kf_grp_bits / (double)allocation_chunks));
       if (cpi->twopass.kf_bits > alt_kf_bits) {
         cpi->twopass.kf_bits = alt_kf_bits;
       }
     } else {
     // Else if it is much harder than other frames in the group make sure
     // it at least receives an allocation in keeping with its relative
     // error score
       alt_kf_bits =
         (int)((double)cpi->twopass.bits_left *
               (kf_mod_err /
                DOUBLE_DIVIDE_CHECK(cpi->twopass.modified_error_left)));
       if (alt_kf_bits > cpi->twopass.kf_bits) {
         cpi->twopass.kf_bits = alt_kf_bits;
       }
     }
     cpi->twopass.kf_group_bits -= cpi->twopass.kf_bits;
     // Add in the minimum frame allowance
     cpi->twopass.kf_bits += cpi->min_frame_bandwidth;
     // Peer frame bit target for this frame
     cpi->per_frame_bandwidth = cpi->twopass.kf_bits;
     // Convert to a per second bitrate
     cpi->target_bandwidth = (int)(cpi->twopass.kf_bits *
                                   cpi->output_framerate);
   }
   // Note the total error score of the kf group minus the key frame itself
   cpi->twopass.kf_group_error_left = (int)(kf_group_err - kf_mod_err);
   // Adjust the count of total modified error left.
   // The count of bits left is adjusted elsewhere based on real coded frame
   // sizes.
   cpi->twopass.modified_error_left -= kf_group_err;
 }

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media/libvpx/vp9/encoder/vp9_firstpass.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_firstpass.c