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 /*

  *  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] = {

   0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,

   0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,

   0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,

   0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,

   0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.031250, 0.062500,

   0.093750, 0.125000, 0.156250, 0.187500, 0.218750, 0.250000, 0.281250,

   0.312500, 0.343750, 0.375000, 0.406250, 0.437500, 0.468750, 0.500000,

   0.531250, 0.562500, 0.593750, 0.625000, 0.656250, 0.687500, 0.718750,

   0.750000, 0.781250, 0.812500, 0.843750, 0.875000, 0.906250, 0.937500,

   0.968750, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,

   1.000000, 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)) >

         2.0))) {

     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 ?

                           1.04 + (/*cpi->oxcf.cpu_used*/0 * 0.04) :

                           1.25;

   // 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 =

     12 + ((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.