1 /*****************************************************************************
2 * ratecontrol.c: h264 encoder library (Rate Control)
3 *****************************************************************************
4 * Copyright (C) 2005-2008 x264 project
6 * Authors: Loren Merritt <lorenm@u.washington.edu>
7 * Michael Niedermayer <michaelni@gmx.at>
8 * Gabriel Bouvigne <gabriel.bouvigne@joost.com>
9 * Fiona Glaser <fiona@x264.com>
10 * Måns Rullgård <mru@mru.ath.cx>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA.
25 *****************************************************************************/
27 #define _ISOC99_SOURCE
28 #undef NDEBUG // always check asserts, the speed effect is far too small to disable them
31 #include "common/common.h"
32 #include "ratecontrol.h"
44 uint64_t expected_bits; /*total expected bits up to the current frame (current one excluded)*/
51 float blurred_complexity;
54 int16_t i_weight_denom;
59 } ratecontrol_entry_t;
69 struct x264_ratecontrol_t
78 double rate_tolerance;
80 int nmb; /* number of macroblocks in a frame */
84 ratecontrol_entry_t *rce;
85 int qp; /* qp for current frame */
86 float qpm; /* qp for current macroblock: precise float for AQ */
87 float qpa_rc; /* average of macroblocks' qp before aq */
88 float qpa_aq; /* average of macroblocks' qp after aq */
89 float qp_novbv; /* QP for the current frame if 1-pass VBV was disabled. */
94 int64_t buffer_fill_final;
95 double buffer_fill; /* planned buffer, if all in-progress frames hit their bit budget */
96 double buffer_rate; /* # of bits added to buffer_fill after each frame */
97 double vbv_max_rate; /* # of bits added to buffer_fill per second */
98 predictor_t *pred; /* predict frame size from satd */
100 double rate_factor_max_increment; /* Don't allow RF above (CRF + this value). */
105 double cplxr_sum; /* sum of bits*qscale/rceq */
106 double expected_bits_sum; /* sum of qscale2bits after rceq, ratefactor, and overflow, only includes finished frames */
107 double wanted_bits_window; /* target bitrate * window */
109 double short_term_cplxsum;
110 double short_term_cplxcount;
111 double rate_factor_constant;
116 FILE *p_stat_file_out;
117 char *psz_stat_file_tmpname;
118 FILE *p_mbtree_stat_file_out;
119 char *psz_mbtree_stat_file_tmpname;
120 char *psz_mbtree_stat_file_name;
121 FILE *p_mbtree_stat_file_in;
123 int num_entries; /* number of ratecontrol_entry_ts */
124 ratecontrol_entry_t *entry; /* FIXME: copy needed data and free this once init is done */
126 double last_qscale_for[5]; /* last qscale for a specific pict type, used for max_diff & ipb factor stuff */
127 int last_non_b_pict_type;
128 double accum_p_qp; /* for determining I-frame quant */
130 double last_accum_p_norm;
131 double lmin[5]; /* min qscale by frame type */
133 double lstep; /* max change (multiply) in qscale per frame */
134 uint16_t *qp_buffer[2]; /* Global buffers for converting MB-tree quantizer data. */
135 int qpbuf_pos; /* In order to handle pyramid reordering, QP buffer acts as a stack.
136 * This value is the current position (0 or 1). */
139 float frame_size_estimated; /* Access to this variable must be atomic: double is
140 * not atomic on all arches we care about */
141 double frame_size_maximum; /* Maximum frame size due to MinCR */
142 double frame_size_planned;
143 double slice_size_planned;
144 double max_frame_error;
145 predictor_t (*row_pred)[2];
146 predictor_t row_preds[5][2];
147 predictor_t *pred_b_from_p; /* predict B-frame size from P-frame satd */
148 int bframes; /* # consecutive B-frames before this P-frame */
149 int bframe_bits; /* total cost of those frames */
153 x264_zone_t *prev_zone;
156 int initial_cpb_removal_delay;
157 int initial_cpb_removal_delay_offset;
158 double nrt_first_access_unit; /* nominal removal time */
159 double previous_cpb_final_arrival_time;
160 uint64_t hrd_multiply_denom;
164 static int parse_zones( x264_t *h );
165 static int init_pass2(x264_t *);
166 static float rate_estimate_qscale( x264_t *h );
167 static int update_vbv( x264_t *h, int bits );
168 static void update_vbv_plan( x264_t *h, int overhead );
169 static double predict_size( predictor_t *p, double q, double var );
170 static void update_predictor( predictor_t *p, double q, double var, double bits );
172 #define CMP_OPT_FIRST_PASS( opt, param_val )\
174 if( ( p = strstr( opts, opt "=" ) ) && sscanf( p, opt "=%d" , &i ) && param_val != i )\
176 x264_log( h, X264_LOG_ERROR, "different " opt " setting than first pass (%d vs %d)\n", param_val, i );\
182 * qp = h.264's quantizer
183 * qscale = linearized quantizer = Lagrange multiplier
185 static inline double qp2qscale( double qp )
187 return 0.85 * pow( 2.0, ( qp - 12.0 ) / 6.0 );
189 static inline double qscale2qp( double qscale )
191 return 12.0 + 6.0 * log2( qscale/0.85 );
194 /* Texture bitrate is not quite inversely proportional to qscale,
195 * probably due the the changing number of SKIP blocks.
196 * MV bits level off at about qp<=12, because the lambda used
197 * for motion estimation is constant there. */
198 static inline double qscale2bits( ratecontrol_entry_t *rce, double qscale )
202 return (rce->tex_bits + .1) * pow( rce->qscale / qscale, 1.1 )
203 + rce->mv_bits * pow( X264_MAX(rce->qscale, 1) / X264_MAX(qscale, 1), 0.5 )
207 static ALWAYS_INLINE uint32_t ac_energy_plane( x264_t *h, int mb_x, int mb_y, x264_frame_t *frame, int i )
210 int shift = i ? 6 : 8;
211 int stride = frame->i_stride[i];
212 int offset = h->mb.b_interlaced
213 ? w * (mb_x + (mb_y&~1) * stride) + (mb_y&1) * stride
214 : w * (mb_x + mb_y * stride);
215 int pix = i ? PIXEL_8x8 : PIXEL_16x16;
216 stride <<= h->mb.b_interlaced;
217 uint64_t res = h->pixf.var[pix]( frame->plane[i] + offset, stride );
218 uint32_t sum = (uint32_t)res;
219 uint32_t ssd = res >> 32;
220 frame->i_pixel_sum[i] += sum;
221 frame->i_pixel_ssd[i] += ssd;
222 return ssd - ((uint64_t)sum * sum >> shift);
225 // Find the total AC energy of the block in all planes.
226 static NOINLINE uint32_t x264_ac_energy_mb( x264_t *h, int mb_x, int mb_y, x264_frame_t *frame )
228 /* This function contains annoying hacks because GCC has a habit of reordering emms
229 * and putting it after floating point ops. As a result, we put the emms at the end of the
230 * function and make sure that its always called before the float math. Noinline makes
231 * sure no reordering goes on. */
232 uint32_t var = ac_energy_plane( h, mb_x, mb_y, frame, 0 );
233 var += ac_energy_plane( h, mb_x, mb_y, frame, 1 );
234 var += ac_energy_plane( h, mb_x, mb_y, frame, 2 );
239 void x264_adaptive_quant_frame( x264_t *h, x264_frame_t *frame, float *quant_offsets )
241 /* constants chosen to result in approximately the same overall bitrate as without AQ.
242 * FIXME: while they're written in 5 significant digits, they're only tuned to 2. */
245 /* Initialize frame stats */
246 for( int i = 0; i < 3; i++ )
248 frame->i_pixel_sum[i] = 0;
249 frame->i_pixel_ssd[i] = 0;
252 /* Degenerate cases */
253 if( h->param.rc.i_aq_mode == X264_AQ_NONE || h->param.rc.f_aq_strength == 0 )
255 /* Need to init it anyways for MB tree */
256 if( h->param.rc.i_aq_mode && h->param.rc.f_aq_strength == 0 )
260 for( int mb_xy = 0; mb_xy < h->mb.i_mb_count; mb_xy++ )
261 frame->f_qp_offset[mb_xy] = frame->f_qp_offset_aq[mb_xy] = quant_offsets[mb_xy];
262 if( h->frames.b_have_lowres )
263 for( int mb_xy = 0; mb_xy < h->mb.i_mb_count; mb_xy++ )
264 frame->i_inv_qscale_factor[mb_xy] = x264_exp2fix8( frame->f_qp_offset[mb_xy] );
268 memset( frame->f_qp_offset, 0, h->mb.i_mb_count * sizeof(float) );
269 memset( frame->f_qp_offset_aq, 0, h->mb.i_mb_count * sizeof(float) );
270 if( h->frames.b_have_lowres )
271 for( int mb_xy = 0; mb_xy < h->mb.i_mb_count; mb_xy++ )
272 frame->i_inv_qscale_factor[mb_xy] = 256;
275 /* Need variance data for weighted prediction */
276 if( h->param.analyse.i_weighted_pred == X264_WEIGHTP_FAKE || h->param.analyse.i_weighted_pred == X264_WEIGHTP_SMART )
278 for( int mb_y = 0; mb_y < h->mb.i_mb_height; mb_y++ )
279 for( int mb_x = 0; mb_x < h->mb.i_mb_width; mb_x++ )
280 x264_ac_energy_mb( h, mb_x, mb_y, frame );
285 /* Actual adaptive quantization */
288 if( h->param.rc.i_aq_mode == X264_AQ_AUTOVARIANCE )
290 float bit_depth_correction = powf(1 << (BIT_DEPTH-8), 0.5f);
291 float avg_adj_pow2 = 0.f;
292 for( int mb_y = 0; mb_y < h->mb.i_mb_height; mb_y++ )
293 for( int mb_x = 0; mb_x < h->mb.i_mb_width; mb_x++ )
295 uint32_t energy = x264_ac_energy_mb( h, mb_x, mb_y, frame );
296 float qp_adj = powf( energy + 1, 0.125f );
297 frame->f_qp_offset[mb_x + mb_y*h->mb.i_mb_stride] = qp_adj;
299 avg_adj_pow2 += qp_adj * qp_adj;
301 avg_adj /= h->mb.i_mb_count;
302 avg_adj_pow2 /= h->mb.i_mb_count;
303 strength = h->param.rc.f_aq_strength * avg_adj / bit_depth_correction;
304 avg_adj = avg_adj - 0.5f * (avg_adj_pow2 - (14.f * bit_depth_correction)) / avg_adj;
307 strength = h->param.rc.f_aq_strength * 1.0397f;
309 for( int mb_y = 0; mb_y < h->mb.i_mb_height; mb_y++ )
310 for( int mb_x = 0; mb_x < h->mb.i_mb_width; mb_x++ )
313 int mb_xy = mb_x + mb_y*h->mb.i_mb_stride;
314 if( h->param.rc.i_aq_mode == X264_AQ_AUTOVARIANCE )
316 qp_adj = frame->f_qp_offset[mb_xy];
317 qp_adj = strength * (qp_adj - avg_adj);
321 uint32_t energy = x264_ac_energy_mb( h, mb_x, mb_y, frame );
322 qp_adj = strength * (x264_log2( X264_MAX(energy, 1) ) - (14.427f + 2*(BIT_DEPTH-8)));
325 qp_adj += quant_offsets[mb_xy];
326 frame->f_qp_offset[mb_xy] =
327 frame->f_qp_offset_aq[mb_xy] = qp_adj;
328 if( h->frames.b_have_lowres )
329 frame->i_inv_qscale_factor[mb_xy] = x264_exp2fix8(qp_adj);
333 /* Remove mean from SSD calculation */
334 for( int i = 0; i < 3; i++ )
336 uint64_t ssd = frame->i_pixel_ssd[i];
337 uint64_t sum = frame->i_pixel_sum[i];
338 int width = h->mb.i_mb_width*16>>!!i;
339 int height = h->mb.i_mb_height*16>>!!i;
340 frame->i_pixel_ssd[i] = ssd - (sum * sum + width * height / 2) / (width * height);
344 int x264_macroblock_tree_read( x264_t *h, x264_frame_t *frame, float *quant_offsets )
346 x264_ratecontrol_t *rc = h->rc;
347 uint8_t i_type_actual = rc->entry[frame->i_frame].pict_type;
349 if( rc->entry[frame->i_frame].kept_as_ref )
352 if( rc->qpbuf_pos < 0 )
358 if( !fread( &i_type, 1, 1, rc->p_mbtree_stat_file_in ) )
360 if( fread( rc->qp_buffer[rc->qpbuf_pos], sizeof(uint16_t), h->mb.i_mb_count, rc->p_mbtree_stat_file_in ) != h->mb.i_mb_count )
363 if( i_type != i_type_actual && rc->qpbuf_pos == 1 )
365 x264_log(h, X264_LOG_ERROR, "MB-tree frametype %d doesn't match actual frametype %d.\n", i_type, i_type_actual);
368 } while( i_type != i_type_actual );
371 for( int i = 0; i < h->mb.i_mb_count; i++ )
373 frame->f_qp_offset[i] = ((float)(int16_t)endian_fix16( rc->qp_buffer[rc->qpbuf_pos][i] )) * (1/256.0);
374 if( h->frames.b_have_lowres )
375 frame->i_inv_qscale_factor[i] = x264_exp2fix8(frame->f_qp_offset[i]);
380 x264_adaptive_quant_frame( h, frame, quant_offsets );
383 x264_log(h, X264_LOG_ERROR, "Incomplete MB-tree stats file.\n");
387 int x264_reference_build_list_optimal( x264_t *h )
389 ratecontrol_entry_t *rce = h->rc->rce;
390 x264_frame_t *frames[16];
391 x264_weight_t weights[16][3];
394 if( rce->refs != h->i_ref0 )
397 memcpy( frames, h->fref0, sizeof(frames) );
398 memcpy( refcount, rce->refcount, sizeof(refcount) );
399 memcpy( weights, h->fenc->weight, sizeof(weights) );
400 memset( &h->fenc->weight[1][0], 0, sizeof(x264_weight_t[15][3]) );
402 /* For now don't reorder ref 0; it seems to lower quality
403 in most cases due to skips. */
404 for( int ref = 1; ref < h->i_ref0; ref++ )
409 for( int i = 1; i < h->i_ref0; i++ )
410 /* Favor lower POC as a tiebreaker. */
411 COPY2_IF_GT( max, refcount[i], bestref, i );
413 /* FIXME: If there are duplicates from frames other than ref0 then it is possible
414 * that the optimal ordering doesnt place every duplicate. */
416 refcount[bestref] = -1;
417 h->fref0[ref] = frames[bestref];
418 memcpy( h->fenc->weight[ref], weights[bestref], sizeof(weights[bestref]) );
424 static char *x264_strcat_filename( char *input, char *suffix )
426 char *output = x264_malloc( strlen( input ) + strlen( suffix ) + 1 );
429 strcpy( output, input );
430 strcat( output, suffix );
434 void x264_ratecontrol_init_reconfigurable( x264_t *h, int b_init )
436 x264_ratecontrol_t *rc = h->rc;
437 if( !b_init && rc->b_2pass )
440 if( h->param.rc.i_rc_method == X264_RC_CRF )
442 /* Arbitrary rescaling to make CRF somewhat similar to QP.
443 * Try to compensate for MB-tree's effects as well. */
444 double base_cplx = h->mb.i_mb_count * (h->param.i_bframe ? 120 : 80);
445 double mbtree_offset = h->param.rc.b_mb_tree ? (1.0-h->param.rc.f_qcompress)*13.5 : 0;
446 rc->rate_factor_constant = pow( base_cplx, 1 - rc->qcompress )
447 / qp2qscale( h->param.rc.f_rf_constant + mbtree_offset );
450 if( h->param.rc.i_vbv_max_bitrate > 0 && h->param.rc.i_vbv_buffer_size > 0 )
452 if( h->param.rc.i_vbv_buffer_size < (int)(h->param.rc.i_vbv_max_bitrate / rc->fps) )
454 h->param.rc.i_vbv_buffer_size = h->param.rc.i_vbv_max_bitrate / rc->fps;
455 x264_log( h, X264_LOG_WARNING, "VBV buffer size cannot be smaller than one frame, using %d kbit\n",
456 h->param.rc.i_vbv_buffer_size );
459 /* We don't support changing the ABR bitrate right now,
460 so if the stream starts as CBR, keep it CBR. */
461 if( rc->b_vbv_min_rate )
462 h->param.rc.i_vbv_max_bitrate = h->param.rc.i_bitrate;
464 int vbv_buffer_size = h->param.rc.i_vbv_buffer_size * 1000;
465 int vbv_max_bitrate = h->param.rc.i_vbv_max_bitrate * 1000;
468 h->sps->vui.hrd.i_bit_rate_unscaled = vbv_max_bitrate;
469 h->sps->vui.hrd.i_cpb_size_unscaled = vbv_buffer_size;
470 if( h->param.i_nal_hrd && b_init )
472 h->sps->vui.hrd.i_cpb_cnt = 1;
473 h->sps->vui.hrd.b_cbr_hrd = h->param.i_nal_hrd == X264_NAL_HRD_CBR;
474 h->sps->vui.hrd.i_time_offset_length = 0;
479 int bitrate = 1000*h->param.rc.i_vbv_max_bitrate;
480 int bufsize = 1000*h->param.rc.i_vbv_buffer_size;
482 // normalize HRD size and rate to the value / scale notation
483 h->sps->vui.hrd.i_bit_rate_scale = x264_clip3( x264_ctz( bitrate ) - BR_SHIFT, 0, 15 );
484 h->sps->vui.hrd.i_bit_rate_value = bitrate >> ( h->sps->vui.hrd.i_bit_rate_scale + BR_SHIFT );
485 h->sps->vui.hrd.i_bit_rate_unscaled = h->sps->vui.hrd.i_bit_rate_value << ( h->sps->vui.hrd.i_bit_rate_scale + BR_SHIFT );
486 h->sps->vui.hrd.i_cpb_size_scale = x264_clip3( x264_ctz( bufsize ) - CPB_SHIFT, 0, 15 );
487 h->sps->vui.hrd.i_cpb_size_value = bufsize >> ( h->sps->vui.hrd.i_cpb_size_scale + CPB_SHIFT );
488 h->sps->vui.hrd.i_cpb_size_unscaled = h->sps->vui.hrd.i_cpb_size_value << ( h->sps->vui.hrd.i_cpb_size_scale + CPB_SHIFT );
494 #define MAX_DURATION 0.5
496 int max_cpb_output_delay = X264_MIN( h->param.i_keyint_max * MAX_DURATION * h->sps->vui.i_time_scale / h->sps->vui.i_num_units_in_tick, INT_MAX );
497 int max_dpb_output_delay = h->sps->vui.i_max_dec_frame_buffering * MAX_DURATION * h->sps->vui.i_time_scale / h->sps->vui.i_num_units_in_tick;
498 int max_delay = (int)(90000.0 * (double)h->sps->vui.hrd.i_cpb_size_unscaled / h->sps->vui.hrd.i_bit_rate_unscaled + 0.5);
500 h->sps->vui.hrd.i_initial_cpb_removal_delay_length = 2 + x264_clip3( 32 - x264_clz( max_delay ), 4, 22 );
501 h->sps->vui.hrd.i_cpb_removal_delay_length = x264_clip3( 32 - x264_clz( max_cpb_output_delay ), 4, 31 );
502 h->sps->vui.hrd.i_dpb_output_delay_length = x264_clip3( 32 - x264_clz( max_dpb_output_delay ), 4, 31 );
506 vbv_buffer_size = h->sps->vui.hrd.i_cpb_size_unscaled;
507 vbv_max_bitrate = h->sps->vui.hrd.i_bit_rate_unscaled;
509 else if( h->param.i_nal_hrd && !b_init )
511 x264_log( h, X264_LOG_WARNING, "VBV parameters cannot be changed when NAL HRD is in use\n" );
515 rc->buffer_rate = vbv_max_bitrate / rc->fps;
516 rc->vbv_max_rate = vbv_max_bitrate;
517 rc->buffer_size = vbv_buffer_size;
518 rc->single_frame_vbv = rc->buffer_rate * 1.1 > rc->buffer_size;
519 rc->cbr_decay = 1.0 - rc->buffer_rate / rc->buffer_size
520 * 0.5 * X264_MAX(0, 1.5 - rc->buffer_rate * rc->fps / rc->bitrate);
521 if( h->param.rc.i_rc_method == X264_RC_CRF && h->param.rc.f_rf_constant_max )
523 rc->rate_factor_max_increment = h->param.rc.f_rf_constant_max - h->param.rc.f_rf_constant;
524 if( rc->rate_factor_max_increment <= 0 )
526 x264_log( h, X264_LOG_WARNING, "CRF max must be greater than CRF\n" );
527 rc->rate_factor_max_increment = 0;
532 if( h->param.rc.f_vbv_buffer_init > 1. )
533 h->param.rc.f_vbv_buffer_init = x264_clip3f( h->param.rc.f_vbv_buffer_init / h->param.rc.i_vbv_buffer_size, 0, 1 );
534 h->param.rc.f_vbv_buffer_init = x264_clip3f( X264_MAX( h->param.rc.f_vbv_buffer_init, rc->buffer_rate / rc->buffer_size ), 0, 1);
535 rc->buffer_fill_final = rc->buffer_size * h->param.rc.f_vbv_buffer_init * h->sps->vui.i_time_scale;
537 rc->b_vbv_min_rate = !rc->b_2pass
538 && h->param.rc.i_rc_method == X264_RC_ABR
539 && h->param.rc.i_vbv_max_bitrate <= h->param.rc.i_bitrate;
544 int x264_ratecontrol_new( x264_t *h )
546 x264_ratecontrol_t *rc;
550 CHECKED_MALLOCZERO( h->rc, h->param.i_threads * sizeof(x264_ratecontrol_t) );
553 rc->b_abr = h->param.rc.i_rc_method != X264_RC_CQP && !h->param.rc.b_stat_read;
554 rc->b_2pass = h->param.rc.i_rc_method == X264_RC_ABR && h->param.rc.b_stat_read;
556 /* FIXME: use integers */
557 if( h->param.i_fps_num > 0 && h->param.i_fps_den > 0 )
558 rc->fps = (float) h->param.i_fps_num / h->param.i_fps_den;
562 if( h->param.rc.b_mb_tree )
564 h->param.rc.f_pb_factor = 1;
568 rc->qcompress = h->param.rc.f_qcompress;
570 rc->bitrate = h->param.rc.i_bitrate * 1000.;
571 rc->rate_tolerance = h->param.rc.f_rate_tolerance;
572 rc->nmb = h->mb.i_mb_count;
573 rc->last_non_b_pict_type = -1;
576 if( h->param.rc.i_rc_method == X264_RC_CRF && h->param.rc.b_stat_read )
578 x264_log(h, X264_LOG_ERROR, "constant rate-factor is incompatible with 2pass.\n");
582 x264_ratecontrol_init_reconfigurable( h, 1 );
584 if( h->param.i_nal_hrd )
586 uint64_t denom = (uint64_t)h->sps->vui.hrd.i_bit_rate_unscaled * h->sps->vui.i_time_scale;
587 uint64_t num = 180000;
588 x264_reduce_fraction64( &num, &denom );
589 rc->hrd_multiply_denom = 180000 / num;
591 double bits_required = log2( 180000 / rc->hrd_multiply_denom )
592 + log2( h->sps->vui.i_time_scale )
593 + log2( h->sps->vui.hrd.i_cpb_size_unscaled );
594 if( bits_required >= 63 )
596 x264_log( h, X264_LOG_ERROR, "HRD with very large timescale and bufsize not supported\n" );
601 if( rc->rate_tolerance < 0.01 )
603 x264_log(h, X264_LOG_WARNING, "bitrate tolerance too small, using .01\n");
604 rc->rate_tolerance = 0.01;
607 h->mb.b_variable_qp = rc->b_vbv || h->param.rc.i_aq_mode;
611 /* FIXME ABR_INIT_QP is actually used only in CRF */
612 #define ABR_INIT_QP ( h->param.rc.i_rc_method == X264_RC_CRF ? h->param.rc.f_rf_constant : 24 )
613 rc->accum_p_norm = .01;
614 rc->accum_p_qp = ABR_INIT_QP * rc->accum_p_norm;
615 /* estimated ratio that produces a reasonable QP for the first I-frame */
616 rc->cplxr_sum = .01 * pow( 7.0e5, rc->qcompress ) * pow( h->mb.i_mb_count, 0.5 );
617 rc->wanted_bits_window = 1.0 * rc->bitrate / rc->fps;
618 rc->last_non_b_pict_type = SLICE_TYPE_I;
621 rc->ip_offset = 6.0 * log2f( h->param.rc.f_ip_factor );
622 rc->pb_offset = 6.0 * log2f( h->param.rc.f_pb_factor );
623 rc->qp_constant[SLICE_TYPE_P] = h->param.rc.i_qp_constant;
624 rc->qp_constant[SLICE_TYPE_I] = x264_clip3( h->param.rc.i_qp_constant - rc->ip_offset + 0.5, 0, QP_MAX );
625 rc->qp_constant[SLICE_TYPE_B] = x264_clip3( h->param.rc.i_qp_constant + rc->pb_offset + 0.5, 0, QP_MAX );
626 h->mb.ip_offset = rc->ip_offset + 0.5;
628 rc->lstep = pow( 2, h->param.rc.i_qp_step / 6.0 );
629 rc->last_qscale = qp2qscale( 26 );
630 int num_preds = h->param.b_sliced_threads * h->param.i_threads + 1;
631 CHECKED_MALLOC( rc->pred, 5 * sizeof(predictor_t) * num_preds );
632 CHECKED_MALLOC( rc->pred_b_from_p, sizeof(predictor_t) );
633 for( int i = 0; i < 5; i++ )
635 rc->last_qscale_for[i] = qp2qscale( ABR_INIT_QP );
636 rc->lmin[i] = qp2qscale( h->param.rc.i_qp_min );
637 rc->lmax[i] = qp2qscale( h->param.rc.i_qp_max );
638 for( int j = 0; j < num_preds; j++ )
640 rc->pred[i+j*5].coeff= 2.0;
641 rc->pred[i+j*5].count= 1.0;
642 rc->pred[i+j*5].decay= 0.5;
643 rc->pred[i+j*5].offset= 0.0;
645 for( int j = 0; j < 2; j++ )
647 rc->row_preds[i][j].coeff= .25;
648 rc->row_preds[i][j].count= 1.0;
649 rc->row_preds[i][j].decay= 0.5;
650 rc->row_preds[i][j].offset= 0.0;
653 *rc->pred_b_from_p = rc->pred[0];
655 if( parse_zones( h ) < 0 )
657 x264_log( h, X264_LOG_ERROR, "failed to parse zones\n" );
661 /* Load stat file and init 2pass algo */
662 if( h->param.rc.b_stat_read )
664 char *p, *stats_in, *stats_buf;
666 /* read 1st pass stats */
667 assert( h->param.rc.psz_stat_in );
668 stats_buf = stats_in = x264_slurp_file( h->param.rc.psz_stat_in );
671 x264_log(h, X264_LOG_ERROR, "ratecontrol_init: can't open stats file\n");
674 if( h->param.rc.b_mb_tree )
676 char *mbtree_stats_in = x264_strcat_filename( h->param.rc.psz_stat_in, ".mbtree" );
677 if( !mbtree_stats_in )
679 rc->p_mbtree_stat_file_in = fopen( mbtree_stats_in, "rb" );
680 x264_free( mbtree_stats_in );
681 if( !rc->p_mbtree_stat_file_in )
683 x264_log(h, X264_LOG_ERROR, "ratecontrol_init: can't open mbtree stats file\n");
688 /* check whether 1st pass options were compatible with current options */
689 if( !strncmp( stats_buf, "#options:", 9 ) )
693 char *opts = stats_buf;
694 stats_in = strchr( stats_buf, '\n' );
699 if( sscanf( opts, "#options: %dx%d", &i, &j ) != 2 )
701 x264_log( h, X264_LOG_ERROR, "resolution specified in stats file not valid\n" );
704 else if( h->param.rc.b_mb_tree && (i != h->param.i_width || j != h->param.i_height) )
706 x264_log( h, X264_LOG_ERROR, "MB-tree doesn't support different resolution than 1st pass (%dx%d vs %dx%d)\n",
707 h->param.i_width, h->param.i_height, i, j );
711 if( ( p = strstr( opts, "timebase=" ) ) && sscanf( p, "timebase=%u/%u", &k, &l ) != 2 )
713 x264_log( h, X264_LOG_ERROR, "timebase specified in stats file not valid\n" );
716 if( k != h->param.i_timebase_num || l != h->param.i_timebase_den )
718 x264_log( h, X264_LOG_ERROR, "timebase mismatch with 1st pass (%u/%u vs %u/%u)\n",
719 h->param.i_timebase_num, h->param.i_timebase_den, k, l );
723 CMP_OPT_FIRST_PASS( "weightp", X264_MAX( 0, h->param.analyse.i_weighted_pred ) );
724 CMP_OPT_FIRST_PASS( "bframes", h->param.i_bframe );
725 CMP_OPT_FIRST_PASS( "b_pyramid", h->param.i_bframe_pyramid );
726 CMP_OPT_FIRST_PASS( "intra_refresh", h->param.b_intra_refresh );
727 CMP_OPT_FIRST_PASS( "keyint", h->param.i_keyint_max );
728 CMP_OPT_FIRST_PASS( "open_gop", h->param.i_open_gop );
730 if( strstr( opts, "qp=0" ) && h->param.rc.i_rc_method == X264_RC_ABR )
731 x264_log( h, X264_LOG_WARNING, "1st pass was lossless, bitrate prediction will be inaccurate\n" );
733 if( !strstr( opts, "direct=3" ) && h->param.analyse.i_direct_mv_pred == X264_DIRECT_PRED_AUTO )
735 x264_log( h, X264_LOG_WARNING, "direct=auto not used on the first pass\n" );
736 h->mb.b_direct_auto_write = 1;
739 if( ( p = strstr( opts, "b_adapt=" ) ) && sscanf( p, "b_adapt=%d", &i ) && i >= X264_B_ADAPT_NONE && i <= X264_B_ADAPT_TRELLIS )
740 h->param.i_bframe_adaptive = i;
741 else if( h->param.i_bframe )
743 x264_log( h, X264_LOG_ERROR, "b_adapt method specified in stats file not valid\n" );
747 if( (h->param.rc.b_mb_tree || h->param.rc.i_vbv_buffer_size) && ( p = strstr( opts, "rc_lookahead=" ) ) && sscanf( p, "rc_lookahead=%d", &i ) )
748 h->param.rc.i_lookahead = i;
751 /* find number of pics */
754 for( num_entries = -1; p; num_entries++ )
755 p = strchr( p + 1, ';' );
758 x264_log(h, X264_LOG_ERROR, "empty stats file\n");
761 rc->num_entries = num_entries;
763 if( h->param.i_frame_total < rc->num_entries && h->param.i_frame_total > 0 )
765 x264_log( h, X264_LOG_WARNING, "2nd pass has fewer frames than 1st pass (%d vs %d)\n",
766 h->param.i_frame_total, rc->num_entries );
768 if( h->param.i_frame_total > rc->num_entries )
770 x264_log( h, X264_LOG_ERROR, "2nd pass has more frames than 1st pass (%d vs %d)\n",
771 h->param.i_frame_total, rc->num_entries );
775 CHECKED_MALLOCZERO( rc->entry, rc->num_entries * sizeof(ratecontrol_entry_t) );
777 /* init all to skipped p frames */
778 for( int i = 0; i < rc->num_entries; i++ )
780 ratecontrol_entry_t *rce = &rc->entry[i];
781 rce->pict_type = SLICE_TYPE_P;
782 rce->qscale = rce->new_qscale = qp2qscale( 20 );
783 rce->misc_bits = rc->nmb + 10;
789 for( int i = 0; i < rc->num_entries; i++ )
791 ratecontrol_entry_t *rce;
799 next= strchr(p, ';');
801 *next++ = 0; //sscanf is unbelievably slow on long strings
802 e = sscanf( p, " in:%d ", &frame_number );
804 if( frame_number < 0 || frame_number >= rc->num_entries )
806 x264_log( h, X264_LOG_ERROR, "bad frame number (%d) at stats line %d\n", frame_number, i );
809 rce = &rc->entry[frame_number];
810 rce->direct_mode = 0;
812 e += sscanf( p, " in:%*d out:%*d type:%c dur:%d cpbdur:%d q:%f tex:%d mv:%d misc:%d imb:%d pmb:%d smb:%d d:%c",
813 &pict_type, &rce->i_duration, &rce->i_cpb_duration, &qp, &rce->tex_bits,
814 &rce->mv_bits, &rce->misc_bits, &rce->i_count, &rce->p_count,
815 &rce->s_count, &rce->direct_mode );
817 p = strstr( p, "ref:" );
821 for( ref = 0; ref < 16; ref++ )
823 if( sscanf( p, " %d", &rce->refcount[ref] ) != 1 )
825 p = strchr( p+1, ' ' );
832 rce->i_weight_denom = -1;
833 char *w = strchr( p, 'w' );
835 if( sscanf( w, "w:%hd,%hd,%hd", &rce->i_weight_denom, &rce->weight[0], &rce->weight[1] ) != 3 )
836 rce->i_weight_denom = -1;
838 if( pict_type != 'b' )
839 rce->kept_as_ref = 1;
843 rce->frame_type = X264_TYPE_IDR;
844 rce->pict_type = SLICE_TYPE_I;
847 rce->frame_type = X264_TYPE_I;
848 rce->pict_type = SLICE_TYPE_I;
851 rce->frame_type = X264_TYPE_P;
852 rce->pict_type = SLICE_TYPE_P;
855 rce->frame_type = X264_TYPE_BREF;
856 rce->pict_type = SLICE_TYPE_B;
859 rce->frame_type = X264_TYPE_B;
860 rce->pict_type = SLICE_TYPE_B;
862 default: e = -1; break;
867 x264_log( h, X264_LOG_ERROR, "statistics are damaged at line %d, parser out=%d\n", i, e );
870 rce->qscale = qp2qscale( qp );
874 x264_free( stats_buf );
876 if( h->param.rc.i_rc_method == X264_RC_ABR )
878 if( init_pass2( h ) < 0 )
880 } /* else we're using constant quant, so no need to run the bitrate allocation */
883 /* Open output file */
884 /* If input and output files are the same, output to a temp file
885 * and move it to the real name only when it's complete */
886 if( h->param.rc.b_stat_write )
889 rc->psz_stat_file_tmpname = x264_strcat_filename( h->param.rc.psz_stat_out, ".temp" );
890 if( !rc->psz_stat_file_tmpname )
893 rc->p_stat_file_out = fopen( rc->psz_stat_file_tmpname, "wb" );
894 if( rc->p_stat_file_out == NULL )
896 x264_log(h, X264_LOG_ERROR, "ratecontrol_init: can't open stats file\n");
900 p = x264_param2string( &h->param, 1 );
902 fprintf( rc->p_stat_file_out, "#options: %s\n", p );
904 if( h->param.rc.b_mb_tree && !h->param.rc.b_stat_read )
906 rc->psz_mbtree_stat_file_tmpname = x264_strcat_filename( h->param.rc.psz_stat_out, ".mbtree.temp" );
907 rc->psz_mbtree_stat_file_name = x264_strcat_filename( h->param.rc.psz_stat_out, ".mbtree" );
908 if( !rc->psz_mbtree_stat_file_tmpname || !rc->psz_mbtree_stat_file_name )
911 rc->p_mbtree_stat_file_out = fopen( rc->psz_mbtree_stat_file_tmpname, "wb" );
912 if( rc->p_mbtree_stat_file_out == NULL )
914 x264_log(h, X264_LOG_ERROR, "ratecontrol_init: can't open mbtree stats file\n");
920 if( h->param.rc.b_mb_tree && (h->param.rc.b_stat_read || h->param.rc.b_stat_write) )
922 CHECKED_MALLOC( rc->qp_buffer[0], h->mb.i_mb_count * sizeof(uint16_t) );
923 if( h->param.i_bframe_pyramid && h->param.rc.b_stat_read )
924 CHECKED_MALLOC( rc->qp_buffer[1], h->mb.i_mb_count * sizeof(uint16_t) );
928 for( int i = 0; i<h->param.i_threads; i++ )
930 h->thread[i]->rc = rc+i;
934 h->thread[i]->param = h->param;
935 h->thread[i]->mb.b_variable_qp = h->mb.b_variable_qp;
944 static int parse_zone( x264_t *h, x264_zone_t *z, char *p )
947 char *tok, UNUSED *saveptr=NULL;
949 z->f_bitrate_factor = 1;
950 if( 3 <= sscanf(p, "%u,%u,q=%u%n", &z->i_start, &z->i_end, &z->i_qp, &len) )
952 else if( 3 <= sscanf(p, "%u,%u,b=%f%n", &z->i_start, &z->i_end, &z->f_bitrate_factor, &len) )
954 else if( 2 <= sscanf(p, "%u,%u%n", &z->i_start, &z->i_end, &len) )
958 x264_log( h, X264_LOG_ERROR, "invalid zone: \"%s\"\n", p );
964 CHECKED_MALLOC( z->param, sizeof(x264_param_t) );
965 memcpy( z->param, &h->param, sizeof(x264_param_t) );
966 z->param->param_free = x264_free;
967 while( (tok = strtok_r( p, ",", &saveptr )) )
969 char *val = strchr( tok, '=' );
975 if( x264_param_parse( z->param, tok, val ) )
977 x264_log( h, X264_LOG_ERROR, "invalid zone param: %s = %s\n", tok, val );
987 static int parse_zones( x264_t *h )
989 x264_ratecontrol_t *rc = h->rc;
990 if( h->param.rc.psz_zones && !h->param.rc.i_zones )
993 CHECKED_MALLOC( psz_zones, strlen( h->param.rc.psz_zones )+1 );
994 strcpy( psz_zones, h->param.rc.psz_zones );
995 h->param.rc.i_zones = 1;
996 for( p = psz_zones; *p; p++ )
997 h->param.rc.i_zones += (*p == '/');
998 CHECKED_MALLOC( h->param.rc.zones, h->param.rc.i_zones * sizeof(x264_zone_t) );
1000 for( int i = 0; i < h->param.rc.i_zones; i++ )
1002 int i_tok = strcspn( p, "/" );
1004 if( parse_zone( h, &h->param.rc.zones[i], p ) )
1008 x264_free( psz_zones );
1011 if( h->param.rc.i_zones > 0 )
1013 for( int i = 0; i < h->param.rc.i_zones; i++ )
1015 x264_zone_t z = h->param.rc.zones[i];
1016 if( z.i_start < 0 || z.i_start > z.i_end )
1018 x264_log( h, X264_LOG_ERROR, "invalid zone: start=%d end=%d\n",
1019 z.i_start, z.i_end );
1022 else if( !z.b_force_qp && z.f_bitrate_factor <= 0 )
1024 x264_log( h, X264_LOG_ERROR, "invalid zone: bitrate_factor=%f\n",
1025 z.f_bitrate_factor );
1030 rc->i_zones = h->param.rc.i_zones + 1;
1031 CHECKED_MALLOC( rc->zones, rc->i_zones * sizeof(x264_zone_t) );
1032 memcpy( rc->zones+1, h->param.rc.zones, (rc->i_zones-1) * sizeof(x264_zone_t) );
1034 // default zone to fall back to if none of the others match
1035 rc->zones[0].i_start = 0;
1036 rc->zones[0].i_end = INT_MAX;
1037 rc->zones[0].b_force_qp = 0;
1038 rc->zones[0].f_bitrate_factor = 1;
1039 CHECKED_MALLOC( rc->zones[0].param, sizeof(x264_param_t) );
1040 memcpy( rc->zones[0].param, &h->param, sizeof(x264_param_t) );
1041 for( int i = 1; i < rc->i_zones; i++ )
1043 if( !rc->zones[i].param )
1044 rc->zones[i].param = rc->zones[0].param;
1053 static x264_zone_t *get_zone( x264_t *h, int frame_num )
1055 for( int i = h->rc->i_zones - 1; i >= 0; i-- )
1057 x264_zone_t *z = &h->rc->zones[i];
1058 if( frame_num >= z->i_start && frame_num <= z->i_end )
1064 void x264_ratecontrol_summary( x264_t *h )
1066 x264_ratecontrol_t *rc = h->rc;
1067 if( rc->b_abr && h->param.rc.i_rc_method == X264_RC_ABR && rc->cbr_decay > .9999 )
1069 double base_cplx = h->mb.i_mb_count * (h->param.i_bframe ? 120 : 80);
1070 double mbtree_offset = h->param.rc.b_mb_tree ? (1.0-h->param.rc.f_qcompress)*13.5 : 0;
1071 x264_log( h, X264_LOG_INFO, "final ratefactor: %.2f\n",
1072 qscale2qp( pow( base_cplx, 1 - rc->qcompress )
1073 * rc->cplxr_sum / rc->wanted_bits_window ) - mbtree_offset );
1077 void x264_ratecontrol_delete( x264_t *h )
1079 x264_ratecontrol_t *rc = h->rc;
1082 if( rc->p_stat_file_out )
1084 b_regular_file = x264_is_regular_file( rc->p_stat_file_out );
1085 fclose( rc->p_stat_file_out );
1086 if( h->i_frame >= rc->num_entries && b_regular_file )
1087 if( rename( rc->psz_stat_file_tmpname, h->param.rc.psz_stat_out ) != 0 )
1089 x264_log( h, X264_LOG_ERROR, "failed to rename \"%s\" to \"%s\"\n",
1090 rc->psz_stat_file_tmpname, h->param.rc.psz_stat_out );
1092 x264_free( rc->psz_stat_file_tmpname );
1094 if( rc->p_mbtree_stat_file_out )
1096 b_regular_file = x264_is_regular_file( rc->p_mbtree_stat_file_out );
1097 fclose( rc->p_mbtree_stat_file_out );
1098 if( h->i_frame >= rc->num_entries && b_regular_file )
1099 if( rename( rc->psz_mbtree_stat_file_tmpname, rc->psz_mbtree_stat_file_name ) != 0 )
1101 x264_log( h, X264_LOG_ERROR, "failed to rename \"%s\" to \"%s\"\n",
1102 rc->psz_mbtree_stat_file_tmpname, rc->psz_mbtree_stat_file_name );
1104 x264_free( rc->psz_mbtree_stat_file_tmpname );
1105 x264_free( rc->psz_mbtree_stat_file_name );
1107 if( rc->p_mbtree_stat_file_in )
1108 fclose( rc->p_mbtree_stat_file_in );
1109 x264_free( rc->pred );
1110 x264_free( rc->pred_b_from_p );
1111 x264_free( rc->entry );
1112 x264_free( rc->qp_buffer[0] );
1113 x264_free( rc->qp_buffer[1] );
1116 x264_free( rc->zones[0].param );
1117 for( int i = 1; i < rc->i_zones; i++ )
1118 if( rc->zones[i].param != rc->zones[0].param && rc->zones[i].param->param_free )
1119 rc->zones[i].param->param_free( rc->zones[i].param );
1120 x264_free( rc->zones );
1125 static void accum_p_qp_update( x264_t *h, float qp )
1127 x264_ratecontrol_t *rc = h->rc;
1128 rc->accum_p_qp *= .95;
1129 rc->accum_p_norm *= .95;
1130 rc->accum_p_norm += 1;
1131 if( h->sh.i_type == SLICE_TYPE_I )
1132 rc->accum_p_qp += qp + rc->ip_offset;
1134 rc->accum_p_qp += qp;
1137 /* Before encoding a frame, choose a QP for it */
1138 void x264_ratecontrol_start( x264_t *h, int i_force_qp, int overhead )
1140 x264_ratecontrol_t *rc = h->rc;
1141 ratecontrol_entry_t *rce = NULL;
1142 x264_zone_t *zone = get_zone( h, h->fenc->i_frame );
1147 if( zone && (!rc->prev_zone || zone->param != rc->prev_zone->param) )
1148 x264_encoder_reconfig( h, zone->param );
1149 rc->prev_zone = zone;
1151 rc->qp_force = i_force_qp;
1153 if( h->param.rc.b_stat_read )
1155 int frame = h->fenc->i_frame;
1156 assert( frame >= 0 && frame < rc->num_entries );
1157 rce = h->rc->rce = &h->rc->entry[frame];
1159 if( h->sh.i_type == SLICE_TYPE_B
1160 && h->param.analyse.i_direct_mv_pred == X264_DIRECT_PRED_AUTO )
1162 h->sh.b_direct_spatial_mv_pred = ( rce->direct_mode == 's' );
1163 h->mb.b_direct_auto_read = ( rce->direct_mode == 's' || rce->direct_mode == 't' );
1169 memset( h->fdec->i_row_bits, 0, h->mb.i_mb_height * sizeof(int) );
1170 rc->row_pred = &rc->row_preds[h->sh.i_type];
1171 rc->buffer_rate = h->fenc->i_cpb_duration * rc->vbv_max_rate * h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale;
1172 update_vbv_plan( h, overhead );
1174 const x264_level_t *l = x264_levels;
1175 while( l->level_idc != 0 && l->level_idc != h->param.i_level_idc )
1178 int mincr = l->mincr;
1180 /* Blu-ray requires this */
1181 if( l->level_idc == 41 && h->param.i_nal_hrd )
1184 /* High 10 doesn't require minCR, so just set the maximum to a large value. */
1185 if( h->sps->i_profile_idc == PROFILE_HIGH10 )
1186 rc->frame_size_maximum = 1e9;
1189 /* The spec has a bizarre special case for the first frame. */
1190 if( h->i_frame == 0 )
1192 //384 * ( Max( PicSizeInMbs, fR * MaxMBPS ) + MaxMBPS * ( tr( 0 ) - tr,n( 0 ) ) ) / MinCR
1193 double fr = 1. / 172;
1194 int pic_size_in_mbs = h->mb.i_mb_width * h->mb.i_mb_height;
1195 rc->frame_size_maximum = 384 * BIT_DEPTH * X264_MAX( pic_size_in_mbs, fr*l->mbps ) / mincr;
1199 //384 * MaxMBPS * ( tr( n ) - tr( n - 1 ) ) / MinCR
1200 rc->frame_size_maximum = 384 * BIT_DEPTH * ((double)h->fenc->i_cpb_duration * h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale) * l->mbps / mincr;
1205 if( h->sh.i_type != SLICE_TYPE_B )
1206 rc->bframes = h->fenc->i_bframes;
1212 else if( rc->b_abr )
1214 q = qscale2qp( rate_estimate_qscale( h ) );
1216 else if( rc->b_2pass )
1218 rce->new_qscale = rate_estimate_qscale( h );
1219 q = qscale2qp( rce->new_qscale );
1223 if( h->sh.i_type == SLICE_TYPE_B && h->fdec->b_kept_as_ref )
1224 q = ( rc->qp_constant[ SLICE_TYPE_B ] + rc->qp_constant[ SLICE_TYPE_P ] ) / 2;
1226 q = rc->qp_constant[ h->sh.i_type ];
1230 if( zone->b_force_qp )
1231 q += zone->i_qp - rc->qp_constant[SLICE_TYPE_P];
1233 q -= 6*log2f( zone->f_bitrate_factor );
1237 q = x264_clip3f( q, h->param.rc.i_qp_min, h->param.rc.i_qp_max );
1241 rc->qp = x264_clip3( (int)(q + 0.5), 0, QP_MAX );
1242 h->fdec->f_qp_avg_rc =
1243 h->fdec->f_qp_avg_aq =
1246 rce->new_qp = rc->qp;
1248 accum_p_qp_update( h, rc->qpm );
1250 if( h->sh.i_type != SLICE_TYPE_B )
1251 rc->last_non_b_pict_type = h->sh.i_type;
1254 static double predict_row_size( x264_t *h, int y, double qp )
1256 /* average between two predictors:
1257 * absolute SATD, and scaled bit cost of the colocated row in the previous frame */
1258 x264_ratecontrol_t *rc = h->rc;
1259 double pred_s = predict_size( rc->row_pred[0], qp2qscale( qp ), h->fdec->i_row_satd[y] );
1261 if( h->sh.i_type == SLICE_TYPE_I || qp >= h->fref0[0]->f_row_qp[y] )
1263 if( h->sh.i_type == SLICE_TYPE_P
1264 && h->fref0[0]->i_type == h->fdec->i_type
1265 && h->fref0[0]->i_row_satd[y] > 0
1266 && (abs(h->fref0[0]->i_row_satd[y] - h->fdec->i_row_satd[y]) < h->fdec->i_row_satd[y]/2))
1268 pred_t = h->fref0[0]->i_row_bits[y] * h->fdec->i_row_satd[y] / h->fref0[0]->i_row_satd[y]
1269 * qp2qscale( h->fref0[0]->f_row_qp[y] ) / qp2qscale( qp );
1273 return (pred_s + pred_t) / 2;
1275 /* Our QP is lower than the reference! */
1278 double pred_intra = predict_size( rc->row_pred[1], qp2qscale( qp ), h->fdec->i_row_satds[0][0][y] );
1279 /* Sum: better to overestimate than underestimate by using only one of the two predictors. */
1280 return pred_intra + pred_s;
1284 static double row_bits_so_far( x264_t *h, int y )
1287 for( int i = h->i_threadslice_start; i <= y; i++ )
1288 bits += h->fdec->i_row_bits[i];
1292 static double predict_row_size_sum( x264_t *h, int y, double qp )
1294 double bits = row_bits_so_far(h, y);
1295 for( int i = y+1; i < h->i_threadslice_end; i++ )
1296 bits += predict_row_size( h, i, qp );
1301 void x264_ratecontrol_mb( x264_t *h, int bits )
1303 x264_ratecontrol_t *rc = h->rc;
1304 const int y = h->mb.i_mb_y;
1308 h->fdec->i_row_bits[y] += bits;
1309 rc->qpa_rc += rc->qpm;
1310 rc->qpa_aq += h->mb.i_qp;
1312 if( h->mb.i_mb_x != h->mb.i_mb_width - 1 || !rc->b_vbv )
1315 h->fdec->f_row_qp[y] = rc->qpm;
1317 update_predictor( rc->row_pred[0], qp2qscale( rc->qpm ), h->fdec->i_row_satd[y], h->fdec->i_row_bits[y] );
1318 if( h->sh.i_type == SLICE_TYPE_P && rc->qpm < h->fref0[0]->f_row_qp[y] )
1319 update_predictor( rc->row_pred[1], qp2qscale( rc->qpm ), h->fdec->i_row_satds[0][0][y], h->fdec->i_row_bits[y] );
1321 /* tweak quality based on difference from predicted size */
1322 if( y < h->i_threadslice_end-1 )
1324 float prev_row_qp = h->fdec->f_row_qp[y];
1325 float qp_min = X264_MAX( prev_row_qp - h->param.rc.i_qp_step, h->param.rc.i_qp_min );
1326 float qp_absolute_max = h->param.rc.i_qp_max;
1327 if( rc->rate_factor_max_increment )
1328 qp_absolute_max = X264_MIN( qp_absolute_max, rc->qp_novbv + rc->rate_factor_max_increment );
1329 float qp_max = X264_MIN( prev_row_qp + h->param.rc.i_qp_step, qp_absolute_max );
1330 float step_size = 0.5;
1332 /* B-frames shouldn't use lower QP than their reference frames. */
1333 if( h->sh.i_type == SLICE_TYPE_B )
1335 qp_min = X264_MAX( qp_min, X264_MAX( h->fref0[0]->f_row_qp[y+1], h->fref1[0]->f_row_qp[y+1] ) );
1336 rc->qpm = X264_MAX( rc->qpm, qp_min );
1339 float buffer_left_planned = rc->buffer_fill - rc->frame_size_planned;
1340 float slice_size_planned = h->param.b_sliced_threads ? rc->slice_size_planned : rc->frame_size_planned;
1341 float size_of_other_slices = 0;
1342 if( h->param.b_sliced_threads )
1344 for( int i = 0; i < h->param.i_threads; i++ )
1345 if( h != h->thread[i] )
1346 size_of_other_slices += h->thread[i]->rc->frame_size_estimated;
1349 rc->max_frame_error = X264_MAX( 0.05, 1.0 / (h->mb.i_mb_width) );
1351 /* More threads means we have to be more cautious in letting ratecontrol use up extra bits. */
1352 float rc_tol = buffer_left_planned / h->param.i_threads * rc->rate_tolerance;
1353 int b1 = predict_row_size_sum( h, y, rc->qpm ) + size_of_other_slices;
1355 /* Don't modify the row QPs until a sufficent amount of the bits of the frame have been processed, in case a flat */
1356 /* area at the top of the frame was measured inaccurately. */
1357 if( row_bits_so_far( h, y ) < 0.05 * slice_size_planned )
1360 if( h->sh.i_type != SLICE_TYPE_I )
1363 if( !rc->b_vbv_min_rate )
1364 qp_min = X264_MAX( qp_min, rc->qp_novbv );
1366 while( rc->qpm < qp_max
1367 && ((b1 > rc->frame_size_planned + rc_tol) ||
1368 (rc->buffer_fill - b1 < buffer_left_planned * 0.5) ||
1369 (b1 > rc->frame_size_planned && rc->qpm < rc->qp_novbv)) )
1371 rc->qpm += step_size;
1372 b1 = predict_row_size_sum( h, y, rc->qpm ) + size_of_other_slices;
1375 while( rc->qpm > qp_min
1376 && (rc->qpm > h->fdec->f_row_qp[0] || rc->single_frame_vbv)
1377 && ((b1 < rc->frame_size_planned * 0.8 && rc->qpm <= prev_row_qp)
1378 || b1 < (rc->buffer_fill - rc->buffer_size + rc->buffer_rate) * 1.1) )
1380 rc->qpm -= step_size;
1381 b1 = predict_row_size_sum( h, y, rc->qpm ) + size_of_other_slices;
1384 /* avoid VBV underflow or MinCR violation */
1385 while( (rc->qpm < qp_absolute_max)
1386 && ((rc->buffer_fill - b1 < rc->buffer_rate * rc->max_frame_error) ||
1387 (rc->frame_size_maximum - b1 < rc->frame_size_maximum * rc->max_frame_error)))
1389 rc->qpm += step_size;
1390 b1 = predict_row_size_sum( h, y, rc->qpm ) + size_of_other_slices;
1393 h->rc->frame_size_estimated = predict_row_size_sum( h, y, rc->qpm );
1397 int x264_ratecontrol_qp( x264_t *h )
1400 return x264_clip3( h->rc->qpm + .5, h->param.rc.i_qp_min, h->param.rc.i_qp_max );
1403 int x264_ratecontrol_mb_qp( x264_t *h )
1406 float qp = h->rc->qpm;
1407 if( h->param.rc.i_aq_mode )
1408 /* MB-tree currently doesn't adjust quantizers in unreferenced frames. */
1409 qp += h->fdec->b_kept_as_ref ? h->fenc->f_qp_offset[h->mb.i_mb_xy] : h->fenc->f_qp_offset_aq[h->mb.i_mb_xy];
1410 return x264_clip3( qp + .5, h->param.rc.i_qp_min, h->param.rc.i_qp_max );
1413 /* In 2pass, force the same frame types as in the 1st pass */
1414 int x264_ratecontrol_slice_type( x264_t *h, int frame_num )
1416 x264_ratecontrol_t *rc = h->rc;
1417 if( h->param.rc.b_stat_read )
1419 if( frame_num >= rc->num_entries )
1421 /* We could try to initialize everything required for ABR and
1422 * adaptive B-frames, but that would be complicated.
1423 * So just calculate the average QP used so far. */
1424 h->param.rc.i_qp_constant = (h->stat.i_frame_count[SLICE_TYPE_P] == 0) ? 24
1425 : 1 + h->stat.f_frame_qp[SLICE_TYPE_P] / h->stat.i_frame_count[SLICE_TYPE_P];
1426 rc->qp_constant[SLICE_TYPE_P] = x264_clip3( h->param.rc.i_qp_constant, 0, QP_MAX );
1427 rc->qp_constant[SLICE_TYPE_I] = x264_clip3( (int)( qscale2qp( qp2qscale( h->param.rc.i_qp_constant ) / fabs( h->param.rc.f_ip_factor )) + 0.5 ), 0, QP_MAX );
1428 rc->qp_constant[SLICE_TYPE_B] = x264_clip3( (int)( qscale2qp( qp2qscale( h->param.rc.i_qp_constant ) * fabs( h->param.rc.f_pb_factor )) + 0.5 ), 0, QP_MAX );
1430 x264_log(h, X264_LOG_ERROR, "2nd pass has more frames than 1st pass (%d)\n", rc->num_entries);
1431 x264_log(h, X264_LOG_ERROR, "continuing anyway, at constant QP=%d\n", h->param.rc.i_qp_constant);
1432 if( h->param.i_bframe_adaptive )
1433 x264_log(h, X264_LOG_ERROR, "disabling adaptive B-frames\n");
1435 for( int i = 0; i < h->param.i_threads; i++ )
1437 h->thread[i]->rc->b_abr = 0;
1438 h->thread[i]->rc->b_2pass = 0;
1439 h->thread[i]->param.rc.i_rc_method = X264_RC_CQP;
1440 h->thread[i]->param.rc.b_stat_read = 0;
1441 h->thread[i]->param.i_bframe_adaptive = 0;
1442 h->thread[i]->param.i_scenecut_threshold = 0;
1443 h->thread[i]->param.rc.b_mb_tree = 0;
1444 if( h->thread[i]->param.i_bframe > 1 )
1445 h->thread[i]->param.i_bframe = 1;
1447 return X264_TYPE_AUTO;
1449 return rc->entry[frame_num].frame_type;
1452 return X264_TYPE_AUTO;
1455 void x264_ratecontrol_set_weights( x264_t *h, x264_frame_t *frm )
1457 ratecontrol_entry_t *rce = &h->rc->entry[frm->i_frame];
1458 if( h->param.analyse.i_weighted_pred <= 0 )
1460 if( rce->i_weight_denom >= 0 )
1461 SET_WEIGHT( frm->weight[0][0], 1, rce->weight[0], rce->i_weight_denom, rce->weight[1] );
1464 /* After encoding one frame, save stats and update ratecontrol state */
1465 int x264_ratecontrol_end( x264_t *h, int bits, int *filler )
1467 x264_ratecontrol_t *rc = h->rc;
1468 const int *mbs = h->stat.frame.i_mb_count;
1472 h->stat.frame.i_mb_count_skip = mbs[P_SKIP] + mbs[B_SKIP];
1473 h->stat.frame.i_mb_count_i = mbs[I_16x16] + mbs[I_8x8] + mbs[I_4x4];
1474 h->stat.frame.i_mb_count_p = mbs[P_L0] + mbs[P_8x8];
1475 for( int i = B_DIRECT; i < B_8x8; i++ )
1476 h->stat.frame.i_mb_count_p += mbs[i];
1478 h->fdec->f_qp_avg_rc = rc->qpa_rc /= h->mb.i_mb_count;
1479 h->fdec->f_qp_avg_aq = rc->qpa_aq /= h->mb.i_mb_count;
1481 if( h->param.rc.b_stat_write )
1483 char c_type = h->sh.i_type==SLICE_TYPE_I ? (h->fenc->i_poc==0 ? 'I' : 'i')
1484 : h->sh.i_type==SLICE_TYPE_P ? 'P'
1485 : h->fenc->b_kept_as_ref ? 'B' : 'b';
1486 int dir_frame = h->stat.frame.i_direct_score[1] - h->stat.frame.i_direct_score[0];
1487 int dir_avg = h->stat.i_direct_score[1] - h->stat.i_direct_score[0];
1488 char c_direct = h->mb.b_direct_auto_write ?
1489 ( dir_frame>0 ? 's' : dir_frame<0 ? 't' :
1490 dir_avg>0 ? 's' : dir_avg<0 ? 't' : '-' )
1492 if( fprintf( rc->p_stat_file_out,
1493 "in:%d out:%d type:%c dur:%d cpbdur:%d q:%.2f tex:%d mv:%d misc:%d imb:%d pmb:%d smb:%d d:%c ref:",
1494 h->fenc->i_frame, h->i_frame,
1495 c_type, h->fenc->i_duration,
1496 h->fenc->i_cpb_duration, rc->qpa_rc,
1497 h->stat.frame.i_tex_bits,
1498 h->stat.frame.i_mv_bits,
1499 h->stat.frame.i_misc_bits,
1500 h->stat.frame.i_mb_count_i,
1501 h->stat.frame.i_mb_count_p,
1502 h->stat.frame.i_mb_count_skip,
1506 /* Only write information for reference reordering once. */
1507 int use_old_stats = h->param.rc.b_stat_read && rc->rce->refs > 1;
1508 for( int i = 0; i < (use_old_stats ? rc->rce->refs : h->i_ref0); i++ )
1510 int refcount = use_old_stats ? rc->rce->refcount[i]
1511 : h->param.b_interlaced ? h->stat.frame.i_mb_count_ref[0][i*2]
1512 + h->stat.frame.i_mb_count_ref[0][i*2+1]
1513 : h->stat.frame.i_mb_count_ref[0][i];
1514 if( fprintf( rc->p_stat_file_out, "%d ", refcount ) < 0 )
1518 if( h->sh.weight[0][0].weightfn )
1520 if( fprintf( rc->p_stat_file_out, "w:%"PRId32",%"PRId32",%"PRId32, h->sh.weight[0][0].i_denom, h->sh.weight[0][0].i_scale, h->sh.weight[0][0].i_offset ) < 0 )
1524 if( fprintf( rc->p_stat_file_out, ";\n") < 0 )
1527 /* Don't re-write the data in multi-pass mode. */
1528 if( h->param.rc.b_mb_tree && h->fenc->b_kept_as_ref && !h->param.rc.b_stat_read )
1530 uint8_t i_type = h->sh.i_type;
1531 /* Values are stored as big-endian FIX8.8 */
1532 for( int i = 0; i < h->mb.i_mb_count; i++ )
1533 rc->qp_buffer[0][i] = endian_fix16( h->fenc->f_qp_offset[i]*256.0 );
1534 if( fwrite( &i_type, 1, 1, rc->p_mbtree_stat_file_out ) < 1 )
1536 if( fwrite( rc->qp_buffer[0], sizeof(uint16_t), h->mb.i_mb_count, rc->p_mbtree_stat_file_out ) < h->mb.i_mb_count )
1543 if( h->sh.i_type != SLICE_TYPE_B )
1544 rc->cplxr_sum += bits * qp2qscale( rc->qpa_rc ) / rc->last_rceq;
1547 /* Depends on the fact that B-frame's QP is an offset from the following P-frame's.
1548 * Not perfectly accurate with B-refs, but good enough. */
1549 rc->cplxr_sum += bits * qp2qscale( rc->qpa_rc ) / (rc->last_rceq * fabs( h->param.rc.f_pb_factor ));
1551 rc->cplxr_sum *= rc->cbr_decay;
1552 double frame_duration = (double)h->fenc->i_duration * h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale;
1554 rc->wanted_bits_window += frame_duration * rc->bitrate;
1555 rc->wanted_bits_window *= rc->cbr_decay;
1559 rc->expected_bits_sum += qscale2bits( rc->rce, qp2qscale( rc->rce->new_qp ) );
1561 if( h->mb.b_variable_qp )
1563 if( h->sh.i_type == SLICE_TYPE_B )
1565 rc->bframe_bits += bits;
1566 if( h->fenc->b_last_minigop_bframe )
1568 update_predictor( rc->pred_b_from_p, qp2qscale( rc->qpa_rc ),
1569 h->fref1[h->i_ref1-1]->i_satd, rc->bframe_bits / rc->bframes );
1570 rc->bframe_bits = 0;
1575 *filler = update_vbv( h, bits );
1577 if( h->sps->vui.b_nal_hrd_parameters_present )
1579 if( h->fenc->i_frame == 0 )
1581 // access unit initialises the HRD
1582 h->fenc->hrd_timing.cpb_initial_arrival_time = 0;
1583 rc->initial_cpb_removal_delay = h->initial_cpb_removal_delay;
1584 rc->initial_cpb_removal_delay_offset = h->initial_cpb_removal_delay_offset;
1585 h->fenc->hrd_timing.cpb_removal_time = rc->nrt_first_access_unit = (double)rc->initial_cpb_removal_delay / 90000;
1589 h->fenc->hrd_timing.cpb_removal_time = rc->nrt_first_access_unit + (double)h->fenc->i_cpb_delay *
1590 h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale;
1592 double cpb_earliest_arrival_time = h->fenc->hrd_timing.cpb_removal_time - (double)rc->initial_cpb_removal_delay / 90000;
1593 if( h->fenc->b_keyframe )
1595 rc->nrt_first_access_unit = h->fenc->hrd_timing.cpb_removal_time;
1596 rc->initial_cpb_removal_delay = h->initial_cpb_removal_delay;
1597 rc->initial_cpb_removal_delay_offset = h->initial_cpb_removal_delay_offset;
1600 cpb_earliest_arrival_time -= (double)rc->initial_cpb_removal_delay_offset / 90000;
1602 if( h->sps->vui.hrd.b_cbr_hrd )
1603 h->fenc->hrd_timing.cpb_initial_arrival_time = rc->previous_cpb_final_arrival_time;
1605 h->fenc->hrd_timing.cpb_initial_arrival_time = X264_MAX( rc->previous_cpb_final_arrival_time, cpb_earliest_arrival_time );
1607 int filler_bits = *filler ? X264_MAX( (FILLER_OVERHEAD - h->param.b_annexb), *filler )*8 : 0;
1609 h->fenc->hrd_timing.cpb_final_arrival_time = rc->previous_cpb_final_arrival_time = h->fenc->hrd_timing.cpb_initial_arrival_time +
1610 (double)(bits + filler_bits) / h->sps->vui.hrd.i_bit_rate_unscaled;
1612 h->fenc->hrd_timing.dpb_output_time = (double)h->fenc->i_dpb_output_delay * h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale +
1613 h->fenc->hrd_timing.cpb_removal_time;
1618 x264_log(h, X264_LOG_ERROR, "ratecontrol_end: stats file could not be written to\n");
1622 /****************************************************************************
1624 ***************************************************************************/
1627 * modify the bitrate curve from pass1 for one frame
1629 static double get_qscale(x264_t *h, ratecontrol_entry_t *rce, double rate_factor, int frame_num)
1631 x264_ratecontrol_t *rcc= h->rc;
1632 x264_zone_t *zone = get_zone( h, frame_num );
1633 double q = pow( rce->blurred_complexity, 1 - rcc->qcompress );
1635 // avoid NaN's in the rc_eq
1636 if( !isfinite(q) || rce->tex_bits + rce->mv_bits == 0 )
1637 q = rcc->last_qscale_for[rce->pict_type];
1642 rcc->last_qscale = q;
1647 if( zone->b_force_qp )
1648 q = qp2qscale( zone->i_qp );
1650 q /= zone->f_bitrate_factor;
1656 static double get_diff_limited_q(x264_t *h, ratecontrol_entry_t *rce, double q)
1658 x264_ratecontrol_t *rcc = h->rc;
1659 const int pict_type = rce->pict_type;
1661 // force I/B quants as a function of P quants
1662 const double last_p_q = rcc->last_qscale_for[SLICE_TYPE_P];
1663 const double last_non_b_q= rcc->last_qscale_for[rcc->last_non_b_pict_type];
1664 if( pict_type == SLICE_TYPE_I )
1667 double pq = qp2qscale( rcc->accum_p_qp / rcc->accum_p_norm );
1668 double ip_factor = fabs( h->param.rc.f_ip_factor );
1669 /* don't apply ip_factor if the following frame is also I */
1670 if( rcc->accum_p_norm <= 0 )
1672 else if( h->param.rc.f_ip_factor < 0 )
1674 else if( rcc->accum_p_norm >= 1 )
1677 q = rcc->accum_p_norm * pq / ip_factor + (1 - rcc->accum_p_norm) * iq;
1679 else if( pict_type == SLICE_TYPE_B )
1681 if( h->param.rc.f_pb_factor > 0 )
1683 if( !rce->kept_as_ref )
1684 q *= fabs( h->param.rc.f_pb_factor );
1686 else if( pict_type == SLICE_TYPE_P
1687 && rcc->last_non_b_pict_type == SLICE_TYPE_P
1688 && rce->tex_bits == 0 )
1693 /* last qscale / qdiff stuff */
1694 if( rcc->last_non_b_pict_type == pict_type &&
1695 (pict_type!=SLICE_TYPE_I || rcc->last_accum_p_norm < 1) )
1697 double last_q = rcc->last_qscale_for[pict_type];
1698 double max_qscale = last_q * rcc->lstep;
1699 double min_qscale = last_q / rcc->lstep;
1701 if ( q > max_qscale ) q = max_qscale;
1702 else if( q < min_qscale ) q = min_qscale;
1705 rcc->last_qscale_for[pict_type] = q;
1706 if( pict_type != SLICE_TYPE_B )
1707 rcc->last_non_b_pict_type = pict_type;
1708 if( pict_type == SLICE_TYPE_I )
1710 rcc->last_accum_p_norm = rcc->accum_p_norm;
1711 rcc->accum_p_norm = 0;
1712 rcc->accum_p_qp = 0;
1714 if( pict_type == SLICE_TYPE_P )
1716 float mask = 1 - pow( (float)rce->i_count / rcc->nmb, 2 );
1717 rcc->accum_p_qp = mask * (qscale2qp( q ) + rcc->accum_p_qp);
1718 rcc->accum_p_norm = mask * (1 + rcc->accum_p_norm);
1723 static double predict_size( predictor_t *p, double q, double var )
1725 return (p->coeff*var + p->offset) / (q*p->count);
1728 static void update_predictor( predictor_t *p, double q, double var, double bits )
1730 const double range = 1.5;
1733 double old_coeff = p->coeff / p->count;
1734 double new_coeff = bits*q / var;
1735 double new_coeff_clipped = x264_clip3f( new_coeff, old_coeff/range, old_coeff*range );
1736 double new_offset = bits*q - new_coeff_clipped * var;
1737 if( new_offset >= 0 )
1738 new_coeff = new_coeff_clipped;
1741 p->count *= p->decay;
1742 p->coeff *= p->decay;
1743 p->offset *= p->decay;
1745 p->coeff += new_coeff;
1746 p->offset += new_offset;
1749 // update VBV after encoding a frame
1750 static int update_vbv( x264_t *h, int bits )
1753 int bitrate = h->sps->vui.hrd.i_bit_rate_unscaled;
1754 x264_ratecontrol_t *rcc = h->rc;
1755 x264_ratecontrol_t *rct = h->thread[0]->rc;
1756 uint64_t buffer_size = (uint64_t)h->sps->vui.hrd.i_cpb_size_unscaled * h->sps->vui.i_time_scale;
1758 if( rcc->last_satd >= h->mb.i_mb_count )
1759 update_predictor( &rct->pred[h->sh.i_type], qp2qscale( rcc->qpa_rc ), rcc->last_satd, bits );
1764 rct->buffer_fill_final -= (uint64_t)bits * h->sps->vui.i_time_scale;
1766 if( rct->buffer_fill_final < 0 )
1767 x264_log( h, X264_LOG_WARNING, "VBV underflow (frame %d, %.0f bits)\n", h->i_frame, (double)rct->buffer_fill_final / h->sps->vui.i_time_scale );
1768 rct->buffer_fill_final = X264_MAX( rct->buffer_fill_final, 0 );
1769 rct->buffer_fill_final += (uint64_t)bitrate * h->sps->vui.i_num_units_in_tick * h->fenc->i_cpb_duration;
1771 if( h->sps->vui.hrd.b_cbr_hrd && rct->buffer_fill_final > buffer_size )
1773 filler = ceil( (rct->buffer_fill_final - buffer_size) / (8. * h->sps->vui.i_time_scale) );
1774 bits = X264_MAX( (FILLER_OVERHEAD - h->param.b_annexb), filler ) * 8;
1775 rct->buffer_fill_final -= (uint64_t)bits * h->sps->vui.i_time_scale;
1778 rct->buffer_fill_final = X264_MIN( rct->buffer_fill_final, buffer_size );
1783 void x264_hrd_fullness( x264_t *h )
1785 x264_ratecontrol_t *rct = h->thread[0]->rc;
1786 uint64_t denom = (uint64_t)h->sps->vui.hrd.i_bit_rate_unscaled * h->sps->vui.i_time_scale / rct->hrd_multiply_denom;
1787 uint64_t cpb_state = rct->buffer_fill_final;
1788 uint64_t cpb_size = (uint64_t)h->sps->vui.hrd.i_cpb_size_unscaled * h->sps->vui.i_time_scale;
1789 uint64_t multiply_factor = 180000 / rct->hrd_multiply_denom;
1791 if( rct->buffer_fill_final < 0 || rct->buffer_fill_final > cpb_size )
1793 x264_log( h, X264_LOG_WARNING, "CPB %s: %.0lf bits in a %.0lf-bit buffer\n",
1794 rct->buffer_fill_final < 0 ? "underflow" : "overflow", (float)rct->buffer_fill_final/denom, (float)cpb_size/denom );
1797 h->initial_cpb_removal_delay = (multiply_factor * cpb_state + denom) / (2*denom);
1798 h->initial_cpb_removal_delay_offset = (multiply_factor * cpb_size + denom) / (2*denom) - h->initial_cpb_removal_delay;
1801 // provisionally update VBV according to the planned size of all frames currently in progress
1802 static void update_vbv_plan( x264_t *h, int overhead )
1804 x264_ratecontrol_t *rcc = h->rc;
1805 rcc->buffer_fill = h->thread[0]->rc->buffer_fill_final / h->sps->vui.i_time_scale;
1806 if( h->i_thread_frames > 1 )
1808 int j = h->rc - h->thread[0]->rc;
1809 for( int i = 1; i < h->i_thread_frames; i++ )
1811 x264_t *t = h->thread[ (j+i)%h->i_thread_frames ];
1812 double bits = t->rc->frame_size_planned;
1813 if( !t->b_thread_active )
1815 bits = X264_MAX(bits, t->rc->frame_size_estimated);
1816 rcc->buffer_fill -= bits;
1817 rcc->buffer_fill = X264_MAX( rcc->buffer_fill, 0 );
1818 rcc->buffer_fill += t->rc->buffer_rate;
1819 rcc->buffer_fill = X264_MIN( rcc->buffer_fill, rcc->buffer_size );
1822 rcc->buffer_fill = X264_MIN( rcc->buffer_fill, rcc->buffer_size );
1823 rcc->buffer_fill -= overhead;
1826 // apply VBV constraints and clip qscale to between lmin and lmax
1827 static double clip_qscale( x264_t *h, int pict_type, double q )
1829 x264_ratecontrol_t *rcc = h->rc;
1830 double lmin = rcc->lmin[pict_type];
1831 double lmax = rcc->lmax[pict_type];
1832 if( rcc->rate_factor_max_increment )
1833 lmax = X264_MIN( lmax, qp2qscale( rcc->qp_novbv + rcc->rate_factor_max_increment ) );
1836 /* B-frames are not directly subject to VBV,
1837 * since they are controlled by the P-frames' QPs. */
1839 if( rcc->b_vbv && rcc->last_satd > 0 )
1841 /* Lookahead VBV: raise the quantizer as necessary such that no frames in
1842 * the lookahead overflow and such that the buffer is in a reasonable state
1843 * by the end of the lookahead. */
1844 if( h->param.rc.i_lookahead )
1848 /* Avoid an infinite loop. */
1849 for( int iterations = 0; iterations < 1000 && terminate != 3; iterations++ )
1852 double cur_bits = predict_size( &rcc->pred[h->sh.i_type], q, rcc->last_satd );
1853 double buffer_fill_cur = rcc->buffer_fill - cur_bits;
1855 double total_duration = 0;
1856 frame_q[0] = h->sh.i_type == SLICE_TYPE_I ? q * h->param.rc.f_ip_factor : q;
1857 frame_q[1] = frame_q[0] * h->param.rc.f_pb_factor;
1858 frame_q[2] = frame_q[0] / h->param.rc.f_ip_factor;
1860 /* Loop over the planned future frames. */
1861 for( int j = 0; buffer_fill_cur >= 0 && buffer_fill_cur <= rcc->buffer_size; j++ )
1863 total_duration += h->fenc->f_planned_cpb_duration[j];
1864 buffer_fill_cur += rcc->vbv_max_rate * h->fenc->f_planned_cpb_duration[j];
1865 int i_type = h->fenc->i_planned_type[j];
1866 int i_satd = h->fenc->i_planned_satd[j];
1867 if( i_type == X264_TYPE_AUTO )
1869 i_type = IS_X264_TYPE_I( i_type ) ? SLICE_TYPE_I : IS_X264_TYPE_B( i_type ) ? SLICE_TYPE_B : SLICE_TYPE_P;
1870 cur_bits = predict_size( &rcc->pred[i_type], frame_q[i_type], i_satd );
1871 buffer_fill_cur -= cur_bits;
1873 /* Try to get to get the buffer at least 50% filled, but don't set an impossible goal. */
1874 target_fill = X264_MIN( rcc->buffer_fill + total_duration * rcc->vbv_max_rate * 0.5, rcc->buffer_size * 0.5 );
1875 if( buffer_fill_cur < target_fill )
1881 /* Try to get the buffer no more than 80% filled, but don't set an impossible goal. */
1882 target_fill = x264_clip3f( rcc->buffer_fill - total_duration * rcc->vbv_max_rate * 0.5, rcc->buffer_size * 0.8, rcc->buffer_size );
1883 if( rcc->b_vbv_min_rate && buffer_fill_cur > target_fill )
1892 /* Fallback to old purely-reactive algorithm: no lookahead. */
1895 if( ( pict_type == SLICE_TYPE_P ||
1896 ( pict_type == SLICE_TYPE_I && rcc->last_non_b_pict_type == SLICE_TYPE_I ) ) &&
1897 rcc->buffer_fill/rcc->buffer_size < 0.5 )
1899 q /= x264_clip3f( 2.0*rcc->buffer_fill/rcc->buffer_size, 0.5, 1.0 );
1902 /* Now a hard threshold to make sure the frame fits in VBV.
1903 * This one is mostly for I-frames. */
1904 double bits = predict_size( &rcc->pred[h->sh.i_type], q, rcc->last_satd );
1906 /* For small VBVs, allow the frame to use up the entire VBV. */
1907 double max_fill_factor = h->param.rc.i_vbv_buffer_size >= 5*h->param.rc.i_vbv_max_bitrate / rcc->fps ? 2 : 1;
1908 /* For single-frame VBVs, request that the frame use up the entire VBV. */
1909 double min_fill_factor = rcc->single_frame_vbv ? 1 : 2;
1911 if( bits > rcc->buffer_fill/max_fill_factor )
1912 qf = x264_clip3f( rcc->buffer_fill/(max_fill_factor*bits), 0.2, 1.0 );
1915 if( bits < rcc->buffer_rate/min_fill_factor )
1916 q *= bits*min_fill_factor/rcc->buffer_rate;
1917 q = X264_MAX( q0, q );
1920 /* Apply MinCR restrictions */
1921 double bits = predict_size( &rcc->pred[h->sh.i_type], q, rcc->last_satd );
1922 if( bits > rcc->frame_size_maximum )
1923 q *= bits / rcc->frame_size_maximum;
1924 bits = predict_size( &rcc->pred[h->sh.i_type], q, rcc->last_satd );
1926 /* Check B-frame complexity, and use up any bits that would
1927 * overflow before the next P-frame. */
1928 if( h->sh.i_type == SLICE_TYPE_P && !rcc->single_frame_vbv )
1930 int nb = rcc->bframes;
1931 double pbbits = bits;
1932 double bbits = predict_size( rcc->pred_b_from_p, q * h->param.rc.f_pb_factor, rcc->last_satd );
1934 double bframe_cpb_duration = 0;
1935 double minigop_cpb_duration;
1936 for( int i = 0; i < nb; i++ )
1937 bframe_cpb_duration += h->fenc->f_planned_cpb_duration[1+i];
1939 if( bbits * nb > bframe_cpb_duration * rcc->vbv_max_rate )
1941 pbbits += nb * bbits;
1943 minigop_cpb_duration = bframe_cpb_duration + h->fenc->f_planned_cpb_duration[0];
1944 space = rcc->buffer_fill + minigop_cpb_duration*rcc->vbv_max_rate - rcc->buffer_size;
1945 if( pbbits < space )
1947 q *= X264_MAX( pbbits / space, bits / (0.5 * rcc->buffer_size) );
1949 q = X264_MAX( q0-5, q );
1952 if( !rcc->b_vbv_min_rate )
1953 q = X264_MAX( q0, q );
1958 else if( rcc->b_2pass )
1960 double min2 = log( lmin );
1961 double max2 = log( lmax );
1962 q = (log(q) - min2)/(max2-min2) - 0.5;
1963 q = 1.0/(1.0 + exp( -4*q ));
1964 q = q*(max2-min2) + min2;
1968 return x264_clip3f( q, lmin, lmax );
1971 // update qscale for 1 frame based on actual bits used so far
1972 static float rate_estimate_qscale( x264_t *h )
1975 x264_ratecontrol_t *rcc = h->rc;
1976 ratecontrol_entry_t rce;
1977 int pict_type = h->sh.i_type;
1978 int64_t total_bits = 8*(h->stat.i_frame_size[SLICE_TYPE_I]
1979 + h->stat.i_frame_size[SLICE_TYPE_P]
1980 + h->stat.i_frame_size[SLICE_TYPE_B]);
1985 if( pict_type != rce.pict_type )
1987 x264_log( h, X264_LOG_ERROR, "slice=%c but 2pass stats say %c\n",
1988 slice_type_to_char[pict_type], slice_type_to_char[rce.pict_type] );
1992 if( pict_type == SLICE_TYPE_B )
1994 /* B-frames don't have independent ratecontrol, but rather get the
1995 * average QP of the two adjacent P-frames + an offset */
1997 int i0 = IS_X264_TYPE_I(h->fref0[0]->i_type);
1998 int i1 = IS_X264_TYPE_I(h->fref1[0]->i_type);
1999 int dt0 = abs(h->fenc->i_poc - h->fref0[0]->i_poc);
2000 int dt1 = abs(h->fenc->i_poc - h->fref1[0]->i_poc);
2001 float q0 = h->fref0[0]->f_qp_avg_rc;
2002 float q1 = h->fref1[0]->f_qp_avg_rc;
2004 if( h->fref0[0]->i_type == X264_TYPE_BREF )
2005 q0 -= rcc->pb_offset/2;
2006 if( h->fref1[0]->i_type == X264_TYPE_BREF )
2007 q1 -= rcc->pb_offset/2;
2010 q = (q0 + q1) / 2 + rcc->ip_offset;
2016 q = (q0*dt1 + q1*dt0) / (dt0 + dt1);
2018 if( h->fenc->b_kept_as_ref )
2019 q += rcc->pb_offset/2;
2021 q += rcc->pb_offset;
2023 if( rcc->b_2pass && rcc->b_vbv )
2024 rcc->frame_size_planned = qscale2bits( &rce, q );
2026 rcc->frame_size_planned = predict_size( rcc->pred_b_from_p, q, h->fref1[h->i_ref1-1]->i_satd );
2027 h->rc->frame_size_estimated = rcc->frame_size_planned;
2031 rcc->last_satd = x264_rc_analyse_slice( h );
2033 return qp2qscale( q );
2037 double abr_buffer = 2 * rcc->rate_tolerance * rcc->bitrate;
2041 double lmin = rcc->lmin[pict_type];
2042 double lmax = rcc->lmax[pict_type];
2044 int64_t predicted_bits = total_bits;
2048 if( h->i_thread_frames > 1 )
2050 int j = h->rc - h->thread[0]->rc;
2051 for( int i = 1; i < h->i_thread_frames; i++ )
2053 x264_t *t = h->thread[ (j+i)%h->i_thread_frames ];
2054 double bits = t->rc->frame_size_planned;
2055 if( !t->b_thread_active )
2057 bits = X264_MAX(bits, t->rc->frame_size_estimated);
2058 predicted_bits += (int64_t)bits;
2064 if( h->i_frame < h->i_thread_frames )
2065 predicted_bits += (int64_t)h->i_frame * rcc->bitrate / rcc->fps;
2067 predicted_bits += (int64_t)(h->i_thread_frames - 1) * rcc->bitrate / rcc->fps;
2070 /* Adjust ABR buffer based on distance to the end of the video. */
2071 if( rcc->num_entries > h->i_frame )
2073 double final_bits = rcc->entry[rcc->num_entries-1].expected_bits;
2074 double video_pos = rce.expected_bits / final_bits;
2075 double scale_factor = sqrt( (1 - video_pos) * rcc->num_entries );
2076 abr_buffer *= 0.5 * X264_MAX( scale_factor, 0.5 );
2079 diff = predicted_bits - (int64_t)rce.expected_bits;
2081 q /= x264_clip3f((double)(abr_buffer - diff) / abr_buffer, .5, 2);
2082 if( ((h->i_frame + 1 - h->i_thread_frames) >= rcc->fps) &&
2083 (rcc->expected_bits_sum > 0))
2085 /* Adjust quant based on the difference between
2086 * achieved and expected bitrate so far */
2087 double cur_time = (double)h->i_frame / rcc->num_entries;
2088 double w = x264_clip3f( cur_time*100, 0.0, 1.0 );
2089 q *= pow( (double)total_bits / rcc->expected_bits_sum, w );
2093 /* Do not overflow vbv */
2094 double expected_size = qscale2bits( &rce, q );
2095 double expected_vbv = rcc->buffer_fill + rcc->buffer_rate - expected_size;
2096 double expected_fullness = rce.expected_vbv / rcc->buffer_size;
2097 double qmax = q*(2 - expected_fullness);
2098 double size_constraint = 1 + expected_fullness;
2099 qmax = X264_MAX( qmax, rce.new_qscale );
2100 if( expected_fullness < .05 )
2102 qmax = X264_MIN(qmax, lmax);
2103 while( ((expected_vbv < rce.expected_vbv/size_constraint) && (q < qmax)) ||
2104 ((expected_vbv < 0) && (q < lmax)))
2107 expected_size = qscale2bits(&rce, q);
2108 expected_vbv = rcc->buffer_fill + rcc->buffer_rate - expected_size;
2110 rcc->last_satd = x264_rc_analyse_slice( h );
2112 q = x264_clip3f( q, lmin, lmax );
2114 else /* 1pass ABR */
2116 /* Calculate the quantizer which would have produced the desired
2117 * average bitrate if it had been applied to all frames so far.
2118 * Then modulate that quant based on the current frame's complexity
2119 * relative to the average complexity so far (using the 2pass RCEQ).
2120 * Then bias the quant up or down if total size so far was far from
2122 * Result: Depending on the value of rate_tolerance, there is a
2123 * tradeoff between quality and bitrate precision. But at large
2124 * tolerances, the bit distribution approaches that of 2pass. */
2126 double wanted_bits, overflow = 1;
2128 rcc->last_satd = x264_rc_analyse_slice( h );
2129 rcc->short_term_cplxsum *= 0.5;
2130 rcc->short_term_cplxcount *= 0.5;
2131 rcc->short_term_cplxsum += rcc->last_satd;
2132 rcc->short_term_cplxcount ++;
2134 rce.tex_bits = rcc->last_satd;
2135 rce.blurred_complexity = rcc->short_term_cplxsum / rcc->short_term_cplxcount;
2137 rce.p_count = rcc->nmb;
2141 rce.pict_type = pict_type;
2143 if( h->param.rc.i_rc_method == X264_RC_CRF )
2145 q = get_qscale( h, &rce, rcc->rate_factor_constant, h->fenc->i_frame );
2149 q = get_qscale( h, &rce, rcc->wanted_bits_window / rcc->cplxr_sum, h->fenc->i_frame );
2151 /* ABR code can potentially be counterproductive in CBR, so just don't bother.
2152 * Don't run it if the frame complexity is zero either. */
2153 if( !rcc->b_vbv_min_rate && rcc->last_satd )
2155 // FIXME is it simpler to keep track of wanted_bits in ratecontrol_end?
2156 int i_frame_done = h->i_frame + 1 - h->i_thread_frames;
2157 double time_done = i_frame_done / rcc->fps;
2158 if( h->param.b_vfr_input && i_frame_done > 0 )
2159 time_done = ((double)(h->fenc->i_reordered_pts - h->i_reordered_pts_delay)) * h->param.i_timebase_num / h->param.i_timebase_den;
2160 wanted_bits = time_done * rcc->bitrate;
2161 if( wanted_bits > 0 )
2163 abr_buffer *= X264_MAX( 1, sqrt( time_done ) );
2164 overflow = x264_clip3f( 1.0 + (total_bits - wanted_bits) / abr_buffer, .5, 2 );
2170 if( pict_type == SLICE_TYPE_I && h->param.i_keyint_max > 1
2171 /* should test _next_ pict type, but that isn't decided yet */
2172 && rcc->last_non_b_pict_type != SLICE_TYPE_I )
2174 q = qp2qscale( rcc->accum_p_qp / rcc->accum_p_norm );
2175 q /= fabs( h->param.rc.f_ip_factor );
2177 else if( h->i_frame > 0 )
2179 /* Asymmetric clipping, because symmetric would prevent
2180 * overflow control in areas of rapidly oscillating complexity */
2181 double lmin = rcc->last_qscale_for[pict_type] / rcc->lstep;
2182 double lmax = rcc->last_qscale_for[pict_type] * rcc->lstep;
2183 if( overflow > 1.1 && h->i_frame > 3 )
2185 else if( overflow < 0.9 )
2188 q = x264_clip3f(q, lmin, lmax);
2190 else if( h->param.rc.i_rc_method == X264_RC_CRF && rcc->qcompress != 1 )
2192 q = qp2qscale( ABR_INIT_QP ) / fabs( h->param.rc.f_ip_factor );
2194 rcc->qp_novbv = qscale2qp( q );
2196 //FIXME use get_diff_limited_q() ?
2197 q = clip_qscale( h, pict_type, q );
2200 rcc->last_qscale_for[pict_type] =
2201 rcc->last_qscale = q;
2203 if( !(rcc->b_2pass && !rcc->b_vbv) && h->fenc->i_frame == 0 )
2204 rcc->last_qscale_for[SLICE_TYPE_P] = q * fabs( h->param.rc.f_ip_factor );
2206 if( rcc->b_2pass && rcc->b_vbv )
2207 rcc->frame_size_planned = qscale2bits(&rce, q);
2209 rcc->frame_size_planned = predict_size( &rcc->pred[h->sh.i_type], q, rcc->last_satd );
2211 /* Always use up the whole VBV in this case. */
2212 if( rcc->single_frame_vbv )
2213 rcc->frame_size_planned = rcc->buffer_rate;
2214 h->rc->frame_size_estimated = rcc->frame_size_planned;
2219 void x264_threads_normalize_predictors( x264_t *h )
2221 double totalsize = 0;
2222 for( int i = 0; i < h->param.i_threads; i++ )
2223 totalsize += h->thread[i]->rc->slice_size_planned;
2224 double factor = h->rc->frame_size_planned / totalsize;
2225 for( int i = 0; i < h->param.i_threads; i++ )
2226 h->thread[i]->rc->slice_size_planned *= factor;
2229 void x264_threads_distribute_ratecontrol( x264_t *h )
2232 x264_ratecontrol_t *rc = h->rc;
2234 /* Initialize row predictors */
2235 if( h->i_frame == 0 )
2236 for( int i = 0; i < h->param.i_threads; i++ )
2238 x264_ratecontrol_t *t = h->thread[i]->rc;
2239 memcpy( t->row_preds, rc->row_preds, sizeof(rc->row_preds) );
2242 for( int i = 0; i < h->param.i_threads; i++ )
2244 x264_t *t = h->thread[i];
2245 memcpy( t->rc, rc, offsetof(x264_ratecontrol_t, row_pred) );
2246 t->rc->row_pred = &t->rc->row_preds[h->sh.i_type];
2247 /* Calculate the planned slice size. */
2248 if( rc->b_vbv && rc->frame_size_planned )
2251 for( row = t->i_threadslice_start; row < t->i_threadslice_end; row++ )
2252 size += h->fdec->i_row_satd[row];
2253 t->rc->slice_size_planned = predict_size( &rc->pred[h->sh.i_type + (i+1)*5], rc->qpm, size );
2256 t->rc->slice_size_planned = 0;
2258 if( rc->b_vbv && rc->frame_size_planned )
2260 x264_threads_normalize_predictors( h );
2262 if( rc->single_frame_vbv )
2264 /* Compensate for our max frame error threshold: give more bits (proportionally) to smaller slices. */
2265 for( int i = 0; i < h->param.i_threads; i++ )
2267 x264_t *t = h->thread[i];
2268 t->rc->max_frame_error = X264_MAX( 0.05, 1.0 / (t->i_threadslice_end - t->i_threadslice_start) );
2269 t->rc->slice_size_planned += 2 * t->rc->max_frame_error * rc->frame_size_planned;
2271 x264_threads_normalize_predictors( h );
2274 for( int i = 0; i < h->param.i_threads; i++ )
2275 h->thread[i]->rc->frame_size_estimated = h->thread[i]->rc->slice_size_planned;
2279 void x264_threads_merge_ratecontrol( x264_t *h )
2281 x264_ratecontrol_t *rc = h->rc;
2284 for( int i = 0; i < h->param.i_threads; i++ )
2286 x264_t *t = h->thread[i];
2287 x264_ratecontrol_t *rct = h->thread[i]->rc;
2288 if( h->param.rc.i_vbv_buffer_size )
2291 for( int row = t->i_threadslice_start; row < t->i_threadslice_end; row++ )
2292 size += h->fdec->i_row_satd[row];
2293 int bits = t->stat.frame.i_mv_bits + t->stat.frame.i_tex_bits + t->stat.frame.i_misc_bits;
2294 int mb_count = (t->i_threadslice_end - t->i_threadslice_start) * h->mb.i_mb_width;
2295 update_predictor( &rc->pred[h->sh.i_type+5*i], qp2qscale( rct->qpa_rc/mb_count ), size, bits );
2299 rc->qpa_rc += rct->qpa_rc;
2300 rc->qpa_aq += rct->qpa_aq;
2304 void x264_thread_sync_ratecontrol( x264_t *cur, x264_t *prev, x264_t *next )
2308 #define COPY(var) memcpy(&cur->rc->var, &prev->rc->var, sizeof(cur->rc->var))
2309 /* these vars are updated in x264_ratecontrol_start()
2310 * so copy them from the context that most recently started (prev)
2311 * to the context that's about to start (cur). */
2316 COPY(last_qscale_for);
2317 COPY(last_non_b_pict_type);
2318 COPY(short_term_cplxsum);
2319 COPY(short_term_cplxcount);
2323 /* these vars can be updated by x264_ratecontrol_init_reconfigurable */
2326 COPY(single_frame_vbv);
2328 COPY(b_vbv_min_rate);
2329 COPY(rate_factor_constant);
2335 #define COPY(var) next->rc->var = cur->rc->var
2336 /* these vars are updated in x264_ratecontrol_end()
2337 * so copy them from the context that most recently ended (cur)
2338 * to the context that's about to end (next) */
2340 COPY(expected_bits_sum);
2341 COPY(wanted_bits_window);
2343 COPY(initial_cpb_removal_delay);
2344 COPY(initial_cpb_removal_delay_offset);
2345 COPY(nrt_first_access_unit);
2346 COPY(previous_cpb_final_arrival_time);
2349 //FIXME row_preds[] (not strictly necessary, but would improve prediction)
2350 /* the rest of the variables are either constant or thread-local */
2353 static int find_underflow( x264_t *h, double *fills, int *t0, int *t1, int over )
2355 /* find an interval ending on an overflow or underflow (depending on whether
2356 * we're adding or removing bits), and starting on the earliest frame that
2357 * can influence the buffer fill of that end frame. */
2358 x264_ratecontrol_t *rcc = h->rc;
2359 const double buffer_min = (over ? .1 : .1) * rcc->buffer_size;
2360 const double buffer_max = .9 * rcc->buffer_size;
2361 double fill = fills[*t0-1];
2362 double parity = over ? 1. : -1.;
2363 int start = -1, end = -1;
2364 for( int i = *t0; i < rcc->num_entries; i++ )
2366 fill += (rcc->entry[i].i_cpb_duration * rcc->vbv_max_rate * h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale -
2367 qscale2bits( &rcc->entry[i], rcc->entry[i].new_qscale )) * parity;
2368 fill = x264_clip3f(fill, 0, rcc->buffer_size);
2370 if( fill <= buffer_min || i == 0 )
2376 else if( fill >= buffer_max && start >= 0 )
2381 return start >= 0 && end >= 0;
2384 static int fix_underflow( x264_t *h, int t0, int t1, double adjustment, double qscale_min, double qscale_max)
2386 x264_ratecontrol_t *rcc = h->rc;
2387 double qscale_orig, qscale_new;
2391 for( int i = t0; i <= t1; i++ )
2393 qscale_orig = rcc->entry[i].new_qscale;
2394 qscale_orig = x264_clip3f( qscale_orig, qscale_min, qscale_max );
2395 qscale_new = qscale_orig * adjustment;
2396 qscale_new = x264_clip3f( qscale_new, qscale_min, qscale_max );
2397 rcc->entry[i].new_qscale = qscale_new;
2398 adjusted = adjusted || (qscale_new != qscale_orig);
2403 static double count_expected_bits( x264_t *h )
2405 x264_ratecontrol_t *rcc = h->rc;
2406 double expected_bits = 0;
2407 for( int i = 0; i < rcc->num_entries; i++ )
2409 ratecontrol_entry_t *rce = &rcc->entry[i];
2410 rce->expected_bits = expected_bits;
2411 expected_bits += qscale2bits( rce, rce->new_qscale );
2413 return expected_bits;
2416 static int vbv_pass2( x264_t *h, double all_available_bits )
2418 /* for each interval of buffer_full .. underflow, uniformly increase the qp of all
2419 * frames in the interval until either buffer is full at some intermediate frame or the
2420 * last frame in the interval no longer underflows. Recompute intervals and repeat.
2421 * Then do the converse to put bits back into overflow areas until target size is met */
2423 x264_ratecontrol_t *rcc = h->rc;
2425 double expected_bits = 0;
2427 double prev_bits = 0;
2429 double qscale_min = qp2qscale( h->param.rc.i_qp_min );
2430 double qscale_max = qp2qscale( h->param.rc.i_qp_max );
2432 int adj_min, adj_max;
2433 CHECKED_MALLOC( fills, (rcc->num_entries+1)*sizeof(double) );
2437 /* adjust overall stream size */
2441 prev_bits = expected_bits;
2444 { /* not first iteration */
2445 adjustment = X264_MAX(X264_MIN(expected_bits / all_available_bits, 0.999), 0.9);
2446 fills[-1] = rcc->buffer_size * h->param.rc.f_vbv_buffer_init;
2450 while(adj_min && find_underflow( h, fills, &t0, &t1, 1 ))
2452 adj_min = fix_underflow( h, t0, t1, adjustment, qscale_min, qscale_max );
2457 fills[-1] = rcc->buffer_size * (1. - h->param.rc.f_vbv_buffer_init);
2459 /* fix underflows -- should be done after overflow, as we'd better undersize target than underflowing VBV */
2461 while( adj_max && find_underflow( h, fills, &t0, &t1, 0 ) )
2462 adj_max = fix_underflow( h, t0, t1, 1.001, qscale_min, qscale_max );
2464 expected_bits = count_expected_bits( h );
2465 } while( (expected_bits < .995*all_available_bits) && ((int64_t)(expected_bits+.5) > (int64_t)(prev_bits+.5)) );
2468 x264_log( h, X264_LOG_WARNING, "vbv-maxrate issue, qpmax or vbv-maxrate too low\n");
2470 /* store expected vbv filling values for tracking when encoding */
2471 for( int i = 0; i < rcc->num_entries; i++ )
2472 rcc->entry[i].expected_vbv = rcc->buffer_size - fills[i];
2474 x264_free( fills-1 );
2480 static int init_pass2( x264_t *h )
2482 x264_ratecontrol_t *rcc = h->rc;
2483 uint64_t all_const_bits = 0;
2484 double duration = 0;
2485 for( int i = 0; i < rcc->num_entries; i++ )
2486 duration += rcc->entry[i].i_duration;
2487 duration *= (double)h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale;
2488 uint64_t all_available_bits = h->param.rc.i_bitrate * 1000. * duration;
2489 double rate_factor, step_mult;
2490 double qblur = h->param.rc.f_qblur;
2491 double cplxblur = h->param.rc.f_complexity_blur;
2492 const int filter_size = (int)(qblur*4) | 1;
2493 double expected_bits;
2494 double *qscale, *blurred_qscale;
2496 /* find total/average complexity & const_bits */
2497 for( int i = 0; i < rcc->num_entries; i++ )
2499 ratecontrol_entry_t *rce = &rcc->entry[i];
2500 all_const_bits += rce->misc_bits;
2503 if( all_available_bits < all_const_bits)
2505 x264_log( h, X264_LOG_ERROR, "requested bitrate is too low. estimated minimum is %d kbps\n",
2506 (int)(all_const_bits * rcc->fps / (rcc->num_entries * 1000.)) );
2510 /* Blur complexities, to reduce local fluctuation of QP.
2511 * We don't blur the QPs directly, because then one very simple frame
2512 * could drag down the QP of a nearby complex frame and give it more
2513 * bits than intended. */
2514 for( int i = 0; i < rcc->num_entries; i++ )
2516 ratecontrol_entry_t *rce = &rcc->entry[i];
2517 double weight_sum = 0;
2518 double cplx_sum = 0;
2519 double weight = 1.0;
2520 double gaussian_weight;
2521 /* weighted average of cplx of future frames */
2522 for( int j = 1; j < cplxblur*2 && j < rcc->num_entries-i; j++ )
2524 ratecontrol_entry_t *rcj = &rcc->entry[i+j];
2525 weight *= 1 - pow( (float)rcj->i_count / rcc->nmb, 2 );
2526 if( weight < .0001 )
2528 gaussian_weight = weight * exp( -j*j/200.0 );
2529 weight_sum += gaussian_weight;
2530 cplx_sum += gaussian_weight * (qscale2bits(rcj, 1) - rcj->misc_bits);
2532 /* weighted average of cplx of past frames */
2534 for( int j = 0; j <= cplxblur*2 && j <= i; j++ )
2536 ratecontrol_entry_t *rcj = &rcc->entry[i-j];
2537 gaussian_weight = weight * exp( -j*j/200.0 );
2538 weight_sum += gaussian_weight;
2539 cplx_sum += gaussian_weight * (qscale2bits( rcj, 1 ) - rcj->misc_bits);
2540 weight *= 1 - pow( (float)rcj->i_count / rcc->nmb, 2 );
2541 if( weight < .0001 )
2544 rce->blurred_complexity = cplx_sum / weight_sum;
2547 CHECKED_MALLOC( qscale, sizeof(double)*rcc->num_entries );
2548 if( filter_size > 1 )
2549 CHECKED_MALLOC( blurred_qscale, sizeof(double)*rcc->num_entries );
2551 blurred_qscale = qscale;
2553 /* Search for a factor which, when multiplied by the RCEQ values from
2554 * each frame, adds up to the desired total size.
2555 * There is no exact closed-form solution because of VBV constraints and
2556 * because qscale2bits is not invertible, but we can start with the simple
2557 * approximation of scaling the 1st pass by the ratio of bitrates.
2558 * The search range is probably overkill, but speed doesn't matter here. */
2561 for( int i = 0; i < rcc->num_entries; i++ )
2563 double q = get_qscale(h, &rcc->entry[i], 1.0, i);
2564 expected_bits += qscale2bits(&rcc->entry[i], q);
2565 rcc->last_qscale_for[rcc->entry[i].pict_type] = q;
2567 step_mult = all_available_bits / expected_bits;
2570 for( double step = 1E4 * step_mult; step > 1E-7 * step_mult; step *= 0.5)
2573 rate_factor += step;
2575 rcc->last_non_b_pict_type = -1;
2576 rcc->last_accum_p_norm = 1;
2577 rcc->accum_p_norm = 0;
2580 for( int i = 0; i < rcc->num_entries; i++ )
2582 qscale[i] = get_qscale( h, &rcc->entry[i], rate_factor, i );
2583 rcc->last_qscale_for[rcc->entry[i].pict_type] = qscale[i];
2586 /* fixed I/B qscale relative to P */
2587 for( int i = rcc->num_entries-1; i >= 0; i-- )
2589 qscale[i] = get_diff_limited_q( h, &rcc->entry[i], qscale[i] );
2590 assert(qscale[i] >= 0);
2594 if( filter_size > 1 )
2596 assert( filter_size%2 == 1 );
2597 for( int i = 0; i < rcc->num_entries; i++ )
2599 ratecontrol_entry_t *rce = &rcc->entry[i];
2600 double q = 0.0, sum = 0.0;
2602 for( int j = 0; j < filter_size; j++ )
2604 int idx = i+j-filter_size/2;
2606 double coeff = qblur==0 ? 1.0 : exp( -d*d/(qblur*qblur) );
2607 if( idx < 0 || idx >= rcc->num_entries )
2609 if( rce->pict_type != rcc->entry[idx].pict_type )
2611 q += qscale[idx] * coeff;
2614 blurred_qscale[i] = q/sum;
2618 /* find expected bits */
2619 for( int i = 0; i < rcc->num_entries; i++ )
2621 ratecontrol_entry_t *rce = &rcc->entry[i];
2622 rce->new_qscale = clip_qscale( h, rce->pict_type, blurred_qscale[i] );
2623 assert(rce->new_qscale >= 0);
2624 expected_bits += qscale2bits( rce, rce->new_qscale );
2627 if( expected_bits > all_available_bits )
2628 rate_factor -= step;
2631 x264_free( qscale );
2632 if( filter_size > 1 )
2633 x264_free( blurred_qscale );
2636 if( vbv_pass2( h, all_available_bits ) )
2638 expected_bits = count_expected_bits( h );
2640 if( fabs( expected_bits/all_available_bits - 1.0 ) > 0.01 )
2643 for( int i = 0; i < rcc->num_entries; i++ )
2644 avgq += rcc->entry[i].new_qscale;
2645 avgq = qscale2qp( avgq / rcc->num_entries );
2647 if( expected_bits > all_available_bits || !rcc->b_vbv )
2648 x264_log( h, X264_LOG_WARNING, "Error: 2pass curve failed to converge\n" );
2649 x264_log( h, X264_LOG_WARNING, "target: %.2f kbit/s, expected: %.2f kbit/s, avg QP: %.4f\n",
2650 (float)h->param.rc.i_bitrate,
2651 expected_bits * rcc->fps / (rcc->num_entries * 1000.),
2653 if( expected_bits < all_available_bits && avgq < h->param.rc.i_qp_min + 2 )
2655 if( h->param.rc.i_qp_min > 0 )
2656 x264_log( h, X264_LOG_WARNING, "try reducing target bitrate or reducing qp_min (currently %d)\n", h->param.rc.i_qp_min );
2658 x264_log( h, X264_LOG_WARNING, "try reducing target bitrate\n" );
2660 else if( expected_bits > all_available_bits && avgq > h->param.rc.i_qp_max - 2 )
2662 if( h->param.rc.i_qp_max < QP_MAX )
2663 x264_log( h, X264_LOG_WARNING, "try increasing target bitrate or increasing qp_max (currently %d)\n", h->param.rc.i_qp_max );
2665 x264_log( h, X264_LOG_WARNING, "try increasing target bitrate\n");
2667 else if( !(rcc->b_2pass && rcc->b_vbv) )
2668 x264_log( h, X264_LOG_WARNING, "internal error\n" );