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revision 1.1.2.24, Sun Nov 9 20:49:21 2003 UTC revision 1.9, Tue Mar 9 10:00:14 2010 UTC
# Line 1  Line 1 
1  /******************************************************************************  /******************************************************************************
2   *   *
3   *  XviD Bit Rate Controller Library   *  Xvid Bit Rate Controller Library
4   *  - VBR 2 pass bitrate controller implementation -   *  - VBR 2 pass bitrate controller implementation -
5   *   *
6   *  Copyright (C)      2002 Foxer <email?>   *  Copyright (C)      2002 Benjamin Lambert <foxer@hotmail.com>
7   *                     2002 Dirk Knop <dknop@gwdg.de>   *                     2002 Dirk Knop <dknop@gwdg.de>
8   *                2002-2003 Edouard Gomez <ed.gomez@free.fr>   *                2002-2003 Edouard Gomez <ed.gomez@free.fr>
9   *                     2003 Pete Ross <pross@xvid.org>   *                     2003 Pete Ross <pross@xvid.org>
10   *   *
11   *  This curve treatment algorithm is the one originally implemented by Foxer   *  This curve treatment algorithm is the one originally implemented by Foxer
12   *  and tuned by Dirk Knop for the XviD vfw frontend.   *  and tuned by Dirk Knop for the Xvid vfw frontend.
13   *   *
14   *  This program is free software; you can redistribute it and/or modify   *  This program is free software; you can redistribute it and/or modify
15   *  it under the terms of the GNU General Public License as published by   *  it under the terms of the GNU General Public License as published by
# Line 29  Line 29 
29   *   *
30   *****************************************************************************/   *****************************************************************************/
31    
32    #define BQUANT_PRESCALE
33  #undef COMPENSATE_FORMULA  #undef COMPENSATE_FORMULA
34    
35    /* forces second pass not to be bigger than first */
36    #undef PASS_SMALLER
37    
38    /* automatically alters overflow controls (strength and improvement/degradation)
39            to fight most common problems without user's knowladge */
40    #define SMART_OVERFLOW_SETTING
41    
42  #include <stdio.h>  #include <stdio.h>
43  #include <math.h>  #include <math.h>
44  #include <limits.h>  #include <limits.h>
# Line 39  Line 47 
47  #include "../image/image.h"  #include "../image/image.h"
48    
49  /*****************************************************************************  /*****************************************************************************
50   * Some constants   * Some default settings
51   ****************************************************************************/   ****************************************************************************/
52    
53  #define DEFAULT_KEYFRAME_BOOST 0  #define DEFAULT_KEYFRAME_BOOST 0
54  #define DEFAULT_OVERFLOW_CONTROL_STRENGTH 10  #define DEFAULT_OVERFLOW_CONTROL_STRENGTH 10
55  #define DEFAULT_CURVE_COMPRESSION_HIGH 0  #define DEFAULT_CURVE_COMPRESSION_HIGH 0
56  #define DEFAULT_CURVE_COMPRESSION_LOW 0  #define DEFAULT_CURVE_COMPRESSION_LOW 0
57  #define DEFAULT_MAX_OVERFLOW_IMPROVEMENT 60  #define DEFAULT_MAX_OVERFLOW_IMPROVEMENT 10
58  #define DEFAULT_MAX_OVERFLOW_DEGRADATION 60  #define DEFAULT_MAX_OVERFLOW_DEGRADATION 10
59    
60  /* Keyframe settings */  /* Keyframe settings */
61  #define DEFAULT_KFREDUCTION 20  #define DEFAULT_KFREDUCTION 20
62  #define DEFAULT_MIN_KEY_INTERVAL 1  #define DEFAULT_KFTHRESHOLD 1
63    
64    /*****************************************************************************
65     * Some default constants (can be tuned)
66     ****************************************************************************/
67    
68    /* Specify the invariant part of the headers bits (header+MV)
69     * as  hlength/cst */
70    #define INVARIANT_HEADER_PART_IVOP 1 /* factor 1.0f   */
71    #define INVARIANT_HEADER_PART_PVOP 2 /* factor 0.5f   */
72    #define INVARIANT_HEADER_PART_BVOP 8 /* factor 0.125f */
73    
74  /*****************************************************************************  /*****************************************************************************
75   * Structures   * Structures
# Line 61  Line 79 
79  typedef struct {  typedef struct {
80          int type;               /* first pass type */          int type;               /* first pass type */
81          int quant;              /* first pass quant */          int quant;              /* first pass quant */
         int quant2;             /* Second pass quant */  
82          int blks[3];                    /* k,m,y blks */          int blks[3];                    /* k,m,y blks */
83          int length;             /* first pass length */          int length;             /* first pass length */
84            int invariant;          /* what we assume as being invariant between the two passes, it's a sub part of header + MV bits */
85          int scaled_length;      /* scaled length */          int scaled_length;      /* scaled length */
86          int desired_length;     /* desired length; calculated during encoding */          int desired_length;     /* desired length; calculated during encoding */
87          int error;          int error;
# Line 95  Line 113 
113    
114          /* Total length of each frame types (1st pass) */          /* Total length of each frame types (1st pass) */
115          uint64_t tot_length[3];          uint64_t tot_length[3];
116            uint64_t tot_invariant[3];
117    
118          /* Average length of each frame types (used first for 1st pass data and          /* Average length of each frame types (used first for 1st pass data and
119           * then for scaled averages */           * then for scaled averages */
# Line 115  Line 134 
134    
135          /*----------------------------------          /*----------------------------------
136           * Zones statistical data           * Zones statistical data
          *  
          * ToDo: Fix zones, current  
          *       implementation is buggy  
137           *--------------------------------*/           *--------------------------------*/
138    
         /* Average weight of the zones */  
         double avg_weight;  
   
139          /* Total length used by XVID_ZONE_QUANT zones */          /* Total length used by XVID_ZONE_QUANT zones */
140          int64_t tot_quant;          uint64_t tot_quant;
141            uint64_t tot_quant_invariant;
142    
143            /* Holds the total amount of frame bytes, zone weighted (only scalable
144             * part of frame bytes) */
145            uint64_t tot_weighted;
146    
147          /*----------------------------------          /*----------------------------------
148           * Advanced settings helper ratios           * Advanced settings helper ratios
# Line 159  Line 177 
177          twopass_stat_t * stats;          twopass_stat_t * stats;
178    
179          /*----------------------------------          /*----------------------------------
180           * Histerysis helpers           * Hysteresis helpers
181           *--------------------------------*/           *--------------------------------*/
182    
183          /* This field holds the int2float conversion errors of each quant per          /* This field holds the int2float conversion errors of each quant per
# Line 194  Line 212 
212           * ToDo: description */           * ToDo: description */
213          double fq_error;          double fq_error;
214    
215            int min_quant; /* internal minimal quant, prevents wrong quants from being used */
216    
217          /*----------------------------------          /*----------------------------------
218           * Debug           * Debug
219           *--------------------------------*/           *--------------------------------*/
220          double desired_total;          double desired_total;
221          double real_total;          double real_total;
222    
223            int scaled_frames;
224  } rc_2pass2_t;  } rc_2pass2_t;
225    
226    
# Line 220  Line 242 
242  {  {
243          switch(opt) {          switch(opt) {
244          case XVID_PLG_INFO :          case XVID_PLG_INFO :
245            case XVID_PLG_FRAME :
246                  return 0;                  return 0;
247    
248          case XVID_PLG_CREATE :          case XVID_PLG_CREATE :
# Line 249  Line 272 
272  static void first_pass_stats_prepare_data(rc_2pass2_t * rc);  static void first_pass_stats_prepare_data(rc_2pass2_t * rc);
273  static void first_pass_scale_curve_internal(rc_2pass2_t *rc);  static void first_pass_scale_curve_internal(rc_2pass2_t *rc);
274  static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);  static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);
275    static  int check_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps);
276    static  int scale_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps);
277  #if 0  #if 0
278  static void stats_print(rc_2pass2_t * rc);  static void stats_print(rc_2pass2_t * rc);
279  #endif  #endif
# Line 267  Line 292 
292          if (rc == NULL)          if (rc == NULL)
293                  return XVID_ERR_MEMORY;                  return XVID_ERR_MEMORY;
294    
295          rc->param = *param;          /* v1.0.x */
296            rc->param.version = param->version;
297            rc->param.bitrate = param->bitrate;
298            rc->param.filename = param->filename;
299            rc->param.keyframe_boost = param->keyframe_boost;
300            rc->param.curve_compression_high = param->curve_compression_high;
301            rc->param.curve_compression_low = param->curve_compression_low;
302            rc->param.overflow_control_strength = param->overflow_control_strength;
303            rc->param.max_overflow_improvement = param->max_overflow_improvement;
304            rc->param.max_overflow_degradation = param->max_overflow_degradation;
305            rc->param.kfreduction = param->kfreduction;
306            rc->param.kfthreshold = param->kfthreshold;
307            rc->param.container_frame_overhead = param->container_frame_overhead;
308    
309            if (XVID_VERSION_MINOR(param->version) >= 1) {
310                    rc->param.vbv_size = param->vbv_size;
311                    rc->param.vbv_initial = param->vbv_initial;
312                    rc->param.vbv_maxrate = param->vbv_maxrate;
313                    rc->param.vbv_peakrate = param->vbv_peakrate;
314            }else{
315                    rc->param.vbv_size =
316                    rc->param.vbv_initial =
317                    rc->param.vbv_maxrate =
318                    rc->param.vbv_peakrate = 0;
319            }
320    
321          /* Initialize all defaults */          /* Initialize all defaults */
322  #define _INIT(a, b) if((a) <= 0) (a) = (b)  #define _INIT(a, b) if((a) <= 0) (a) = (b)
# Line 281  Line 330 
330    
331          /* Keyframe settings */          /* Keyframe settings */
332          _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);          _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);
333          _INIT(rc->param.min_key_interval, DEFAULT_MIN_KEY_INTERVAL);          _INIT(rc->param.kfthreshold, DEFAULT_KFTHRESHOLD);
334  #undef _INIT  #undef _INIT
335    
336          /* Initialize some stuff to zero */          /* Initialize some stuff to zero */
# Line 296  Line 345 
345          for (i=0; i<3; i++) rc->last_quant[i] = 0;          for (i=0; i<3; i++) rc->last_quant[i] = 0;
346    
347          rc->fq_error = 0;          rc->fq_error = 0;
348            rc->min_quant = 1;
349            rc->scaled_frames = 0;
350    
351          /* Count frames (and intra frames) in the stats file, store the result into          /* Count frames (and intra frames) in the stats file, store the result into
352           * the rc structure */           * the rc structure */
# Line 332  Line 383 
383          /* Compute the target filesize */          /* Compute the target filesize */
384          if (rc->param.bitrate<0) {          if (rc->param.bitrate<0) {
385                  /* if negative, bitrate equals the target (in kbytes) */                  /* if negative, bitrate equals the target (in kbytes) */
386                  rc->target = (-rc->param.bitrate) * 1024;                  rc->target = ((uint64_t)(-rc->param.bitrate)) * 1024;
387          } else if (rc->num_frames  < create->fbase/create->fincr) {          } else if (rc->num_frames  < create->fbase/create->fincr) {
388                  /* Source sequence is less than 1s long, we do as if it was 1s long */                  /* Source sequence is less than 1s long, we do as if it was 1s long */
389                  rc->target = rc->param.bitrate / 8;                  rc->target = rc->param.bitrate / 8;
# Line 358  Line 409 
409          if(rc->param.container_frame_overhead)          if(rc->param.container_frame_overhead)
410                  DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- New target filesize after container compensation: %lld\n", rc->target);                  DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- New target filesize after container compensation: %lld\n", rc->target);
411    
412            /* When bitrate is not given it means it has been scaled by an external
413             * application */
414            if (rc->param.bitrate) {
415                    /* Apply zone settings
416                     * - set rc->tot_quant which represents the total num of bytes spent in
417                     *   fixed quant zones
418                     * - set rc->tot_weighted which represents the total amount of bytes
419                     *   spent in normal or weighted zones in first pass (normal zones can
420                     *   be considered weight=1)
421                     * - set rc->tot_quant_invariant which represents the total num of bytes
422                     *   spent in fixed quant zones for headers */
423                    zone_process(rc, create);
424            } else {
425                    /* External scaling -- zones are ignored */
426                    for (i=0;i<rc->num_frames;i++) {
427                            rc->stats[i].zone_mode = XVID_ZONE_WEIGHT;
428                            rc->stats[i].weight = 1.0;
429                    }
430                    rc->tot_quant = 0;
431            }
432    
433          /* Gathers some information about first pass stats:          /* Gathers some information about first pass stats:
434           *  - finds the minimum frame length for each frame type during 1st pass.           *  - finds the minimum frame length for each frame type during 1st pass.
435           *     rc->min_size[]           *     rc->min_size[]
# Line 366  Line 438 
438           *  - count how many times each frame type has been used.           *  - count how many times each frame type has been used.
439           *     rc->count[]           *     rc->count[]
440           *  - total bytes used per frame type           *  - total bytes used per frame type
441           *     rc->total[]           *     rc->tot_length[]
442             *  - total bytes considered invariant between the 2 passes
443           *  - store keyframe location           *  - store keyframe location
444           *     rc->keyframe_locations[]           *     rc->keyframe_locations[]
445           */           */
446          first_pass_stats_prepare_data(rc);          first_pass_stats_prepare_data(rc);
447    
448          /* When bitrate is not given it means it has been scaled by an external          /* If we have a user bitrate, it means it's an internal curve scaling */
          * application */  
449          if (rc->param.bitrate) {          if (rc->param.bitrate) {
                 /* Apply zone settings */  
                 zone_process(rc, create);  
450                  /* Perform internal curve scaling */                  /* Perform internal curve scaling */
451                  first_pass_scale_curve_internal(rc);                  first_pass_scale_curve_internal(rc);
         } else {  
                 /* External scaling -- zones are ignored */  
                 for (i=0;i<rc->num_frames;i++) {  
                         rc->stats[i].zone_mode = XVID_ZONE_WEIGHT;  
                         rc->stats[i].weight = 1.0;  
                 }  
                 rc->avg_weight = 1.0;  
                 rc->tot_quant = 0;  
452          }          }
453    
454          /* Apply advanced curve options, and compute some parameters in order to          /* Apply advanced curve options, and compute some parameters in order to
455           * shape the curve in the BEFORE/AFTER pair of functions */           * shape the curve in the BEFORE/AFTER pair of functions */
456          scaled_curve_apply_advanced_parameters(rc);          scaled_curve_apply_advanced_parameters(rc);
457    
458            /* Check curve for VBV compliancy and rescale if necessary */
459    #ifdef VBV_FORCE
460            if (rc->param.vbv_size==0) {
461                    rc->param.vbv_size      =  3145728;
462                    rc->param.vbv_initial   =  2359296;
463                    rc->param.vbv_maxrate   =  4854000;
464                    rc->param.vbv_peakrate  =  8000000;
465            }
466    #endif
467    
468            /* vbv_size==0 switches VBV check off */
469            if (rc->param.vbv_size > 0)  {
470                    const double fps = (double)create->fbase/(double)create->fincr;
471                    int status = check_curve_for_vbv_compliancy(rc, fps);
472    
473                    if (status) {
474                            DPRINTF(XVID_DEBUG_RC, "[xvid rc] Underflow detected - Scaling Curve for compliancy.\n");
475                    }
476    
477                    status = scale_curve_for_vbv_compliancy(rc, fps);
478    
479                    if (status == 0) {
480                            DPRINTF(XVID_DEBUG_RC, "[xvid rc] VBV compliant curve scaling done.\n");
481                    } else {
482                            DPRINTF(XVID_DEBUG_RC, "[xvid rc] VBV compliant curve scaling impossible.\n");
483                    }
484            }
485          *handle = rc;          *handle = rc;
486          return(0);          return(0);
487  }  }
# Line 435  Line 524 
524          if (data->quant > 0)          if (data->quant > 0)
525                  return(0);                  return(0);
526    
527          /* Second case: We are in a Quant zone */          /* Second case: insufficent stats data
528             * We can't guess much what we should do, let core decide all alone */
529            if (data->frame_num >= rc->num_frames) {
530                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- stats file too short (now processing frame %d)",
531                            data->frame_num);
532                    return(0);
533            }
534    
535            /* Third case: We are in a Quant zone
536             * Quant zones must just ensure we use the same settings as first pass
537             * So set the quantizer and the type */
538          if (s->zone_mode == XVID_ZONE_QUANT) {          if (s->zone_mode == XVID_ZONE_QUANT) {
539                    /* Quant stuff */
540                  rc->fq_error += s->weight;                  rc->fq_error += s->weight;
541                  data->quant = (int)rc->fq_error;                  data->quant = (int)rc->fq_error;
542                  rc->fq_error -= data->quant;                  rc->fq_error -= data->quant;
543    
544                    /* The type stuff */
545                    data->type = s->type;
546    
547                    /* The only required data for AFTER step is this one for the overflow
548                     * control */
549                  s->desired_length = s->length;                  s->desired_length = s->length;
550    
551                  return(0);                  return(0);
552          }          }
553    
         /* Third case: insufficent stats data */  
         if (data->frame_num >= rc->num_frames)  
                 return(0);  
554    
555          /*************************************************************************/          /*************************************************************************/
556          /*************************************************************************/          /*************************************************************************/
# Line 466  Line 568 
568    
569          /* IFrame user settings*/          /* IFrame user settings*/
570          if (s->type == XVID_TYPE_IVOP) {          if (s->type == XVID_TYPE_IVOP) {
   
571                  /* Keyframe boosting -- All keyframes benefit from it */                  /* Keyframe boosting -- All keyframes benefit from it */
572                  dbytes += dbytes*rc->param.keyframe_boost / 100;                  dbytes += dbytes*rc->param.keyframe_boost / 100;
573    
574                  /* Applies keyframe penalties, but not the first frame */  #if 0 /* ToDo: decide how to apply kfthresholding */
575                  if (rc->KF_idx) {  #endif
                         int penalty_distance;  
   
                         /* Minimum keyframe distance penalties */  
                         penalty_distance  = rc->param.min_key_interval;  
                         penalty_distance -= rc->keyframe_locations[rc->KF_idx];  
                         penalty_distance += rc->keyframe_locations[rc->KF_idx-1];  
   
                         /* Ah ah ! guilty keyframe, you're under arrest ! */  
                         if (penalty_distance > 0)  
                                 dbytes -= dbytes*penalty_distance*rc->param.kfreduction/100;  
                 }  
576          } else {          } else {
577    
578                  /* P/S/B frames must reserve some bits for iframe boosting */                  /* P/S/B frames must reserve some bits for iframe boosting */
# Line 524  Line 614 
614           *-----------------------------------------------------------------------*/           *-----------------------------------------------------------------------*/
615    
616          /* Compute the overflow we should compensate */          /* Compute the overflow we should compensate */
617          if (s->type != XVID_TYPE_IVOP) {          if (s->type != XVID_TYPE_IVOP || rc->overflow > 0) {
618                  double frametype_factor;                  double frametype_factor;
619                  double framesize_factor;                  double framesize_factor;
620    
# Line 555  Line 645 
645                  /* Apply the overflow strength imposed by the user */                  /* Apply the overflow strength imposed by the user */
646                  overflow *= (rc->param.overflow_control_strength/100.0f);                  overflow *= (rc->param.overflow_control_strength/100.0f);
647          } else {          } else {
648                  /* no overflow applied in IFrames because:                  /* no negative overflow applied in IFrames because:
649                   *  - their role is important as they're references for P/BFrames.                   *  - their role is important as they're references for P/BFrames.
650                   *  - there aren't much in typical sequences, so if an IFrame overflows too                   *  - there aren't much in typical sequences, so if an IFrame overflows too
651                   *    much, this overflow may impact the next IFrame too much and generate                   *    much, this overflow may impact the next IFrame too much and generate
# Line 587  Line 677 
677           * pass nor smaller than the allowed minimum.           * pass nor smaller than the allowed minimum.
678           *-----------------------------------------------------------------------*/           *-----------------------------------------------------------------------*/
679    
680    #ifdef PASS_SMALLER
681          if (dbytes > s->length) {          if (dbytes > s->length) {
682                  dbytes = s->length;                  dbytes = s->length;
683          } else if (dbytes < rc->min_length[s->type-1]) {          }
684    #endif
685    
686            /* Prevent stupid desired sizes under logical values */
687            if (dbytes < rc->min_length[s->type-1]) {
688                  dbytes = rc->min_length[s->type-1];                  dbytes = rc->min_length[s->type-1];
         } else if (dbytes > rc->max_length) {  
                 /* ToDo: this condition is always wrong as max_length == maximum frame  
                  * length of first pass, so the first condition already caps the frame  
                  * size... */  
                 capped_to_max_framesize = 1;  
                 dbytes = rc->max_length;  
                 DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- frame:%d Capped to maximum frame size\n",  
                                 data->frame_num);  
689          }          }
690    
691          /*------------------------------------------------------------------------          /*------------------------------------------------------------------------
692           * Desired frame length <-> quantizer mapping           * Desired frame length <-> quantizer mapping
693           *-----------------------------------------------------------------------*/           *-----------------------------------------------------------------------*/
694    
695          /* For bframes we must retrieve the original quant used (sent to xvidcore)  #ifdef BQUANT_PRESCALE
696           * as core applies the bquant formula before writing the stat log entry */          /* For bframes we prescale the quantizer to avoid too high quant scaling */
697          if(s->type == XVID_TYPE_BVOP) {          if(s->type == XVID_TYPE_BVOP) {
698    
699                  twopass_stat_t *b_ref = s;                  twopass_stat_t *b_ref = s;
# Line 616  Line 703 
703                          b_ref--;                          b_ref--;
704    
705                  /* Compute the original quant */                  /* Compute the original quant */
706                  s->quant  = 100*s->quant - data->bquant_offset;                  s->quant  = 2*(100*s->quant - data->bquant_offset);
707                  s->quant += data->bquant_ratio - 1; /* to avoid rouding issues */                  s->quant += data->bquant_ratio - 1; /* to avoid rounding issues */
708                  s->quant  = s->quant/data->bquant_ratio - b_ref->quant;                  s->quant  = s->quant/data->bquant_ratio - b_ref->quant;
709          }          }
710    #endif
711    
712          /* Don't laugh at this very 'simple' quant<->filesize relationship, it          /* Don't laugh at this very 'simple' quant<->size relationship, it
713           * proves to be acurate enough for our algorithm */           * proves to be acurate enough for our algorithm */
714          scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;          scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;
715    
# Line 682  Line 770 
770                  data->quant = data->max_quant[s->type-1];                  data->quant = data->max_quant[s->type-1];
771          }          }
772    
773            if (data->quant < rc->min_quant) data->quant = rc->min_quant;
774    
775          /* To avoid big quality jumps from frame to frame, we apply a "security"          /* To avoid big quality jumps from frame to frame, we apply a "security"
776           * rule that makes |last_quant - new_quant| <= 2. This rule only applies           * rule that makes |last_quant - new_quant| <= 2. This rule only applies
777           * to predicted frames (P and B) */           * to predicted frames (P and B) */
# Line 707  Line 797 
797                  rc->last_quant[s->type-1] = data->quant;                  rc->last_quant[s->type-1] = data->quant;
798    
799          /* Don't forget to force 1st pass frame type ;-) */          /* Don't forget to force 1st pass frame type ;-) */
800            if (rc->scaled_frames)
801          data->type = s->type;          data->type = s->type;
802    
803          /* Store the quantizer into the statistics -- Used to compensate the double          rc->scaled_frames++;
          * formula symptom */  
         s->quant2 = data->quant;  
   
804          return 0;          return 0;
805  }  }
806    
# Line 774  Line 862 
862                  rc->KFoverflow -= rc->KFoverflow_partial;                  rc->KFoverflow -= rc->KFoverflow_partial;
863          }          }
864    
865          rc->overflow += s->error = s->desired_length - data->length;          s->error = s->desired_length - data->length;
866          rc->real_total += data->length;          rc->real_total += data->length;
867    
868          DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- frame:%d type:%c quant:%d stats:%d scaled:%d desired:%d actual:%d error:%d overflow:%.2f\n",          DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- frame:%d type:%c quant:%d stats:%d scaled:%d desired:%d actual:%d error:%d overflow:%.2f\n",
# Line 823  Line 911 
911    
912                  char *ptr;                  char *ptr;
913                  char type;                  char type;
914                  int fields, nouse;                  int fields;
915    
916                  lines++;                  lines++;
917    
918                  /* We skip spaces */                  /* We skip spaces */
919                  ptr = skipspaces(line);                  ptr = skipspaces(line);
920    
921                  /* Skip coment lines */                  /* Skip coment lines or empty lines */
922                  if(iscomment(ptr)) {                  if(iscomment(ptr) || *ptr == '\0') {
923                          free(line);                          free(line);
924                          continue;                          continue;
925                  }                  }
926    
927                  /* Read the stat line from buffer */                  /* Read the stat line from buffer */
928                  fields = sscanf(ptr,                  fields = sscanf(ptr, "%c", &type);
                                                 "%c %d %d %d %d %d",  
                                                 &type, &nouse, &nouse, &nouse, &nouse, &nouse);  
929    
930                  /* Valid stats files have at least 6 fields */                  /* Valid stats files have at least 7 fields */
931                  if (fields == 6) {                  if (fields == 1) {
932                          switch(type) {                          switch(type) {
933                          case 'i':                          case 'i':
934                          case 'I':                          case 'I':
# Line 863  Line 949 
949                  } else {                  } else {
950                                  DPRINTF(XVID_DEBUG_RC,                                  DPRINTF(XVID_DEBUG_RC,
951                                                  "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",                                                  "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",
952                                                  lines, 6-fields);                                                  lines, 7-fields);
953                  }                  }
954    
955                  /* Free the line buffer */                  /* Free the line buffer */
# Line 873  Line 959 
959          /* We are done with the file */          /* We are done with the file */
960          fclose(f);          fclose(f);
961    
962          return(0);          if (!rc->num_keyframes) return (-1); /* No keyframes? Then something is wrong */
963            else return(0);
964  }  }
965    
966  /* open stats file(s) and read into rc->stats array */  /* open stats file(s) and read into rc->stats array */
# Line 901  Line 988 
988                  /* We skip spaces */                  /* We skip spaces */
989                  ptr = skipspaces(line);                  ptr = skipspaces(line);
990    
991                  /* Skip comment lines */                  /* Skip comment lines or empty lines */
992                  if(iscomment(ptr)) {                  if(iscomment(ptr) || *ptr == '\0') {
993                          free(line);                          free(line);
994                          continue;                          continue;
995                  }                  }
# Line 912  Line 999 
999    
1000                  /* Convert the fields */                  /* Convert the fields */
1001                  fields = sscanf(ptr,                  fields = sscanf(ptr,
1002                                                  "%c %d %d %d %d %d %d\n",                                                  "%c %d %d %d %d %d %d %d\n",
1003                                                  &type,                                                  &type,
1004                                                  &s->quant,                                                  &s->quant,
1005                                                  &s->blks[0], &s->blks[1], &s->blks[2],                                                  &s->blks[0], &s->blks[1], &s->blks[2],
1006                                                  &s->length,                                                  &s->length, &s->invariant /* not really yet */,
1007                                                  &s->scaled_length);                                                  &s->scaled_length);
1008    
1009                  /* Free line buffer, we don't need it anymore */                  /* Free line buffer, we don't need it anymore */
# Line 924  Line 1011 
1011    
1012                  /* Fail silently, this has probably been warned in                  /* Fail silently, this has probably been warned in
1013                   * statsfile_count_frames */                   * statsfile_count_frames */
1014                  if(fields != 6 && fields != 7)                  if(fields != 7 && fields != 8)
1015                          continue;                          continue;
1016    
1017                  /* Convert frame type */                  /* Convert frame type and compute the invariant length part */
1018                  switch(type) {                  switch(type) {
1019                  case 'i':                  case 'i':
1020                  case 'I':                  case 'I':
1021                          s->type = XVID_TYPE_IVOP;                          s->type = XVID_TYPE_IVOP;
1022                            s->invariant /= INVARIANT_HEADER_PART_IVOP;
1023                          break;                          break;
1024                  case 'p':                  case 'p':
1025                  case 'P':                  case 'P':
1026                  case 's':                  case 's':
1027                  case 'S':                  case 'S':
1028                          s->type = XVID_TYPE_PVOP;                          s->type = XVID_TYPE_PVOP;
1029                            s->invariant /= INVARIANT_HEADER_PART_PVOP;
1030                          break;                          break;
1031                  case 'b':                  case 'b':
1032                  case 'B':                  case 'B':
1033                          s->type = XVID_TYPE_BVOP;                          s->type = XVID_TYPE_BVOP;
1034                            s->invariant /= INVARIANT_HEADER_PART_BVOP;
1035                          break;                          break;
1036                  default:                  default:
1037                          /* Same as before, fail silently */                          /* Same as before, fail silently */
# Line 960  Line 1050 
1050    
1051  /* pre-process the statistics data  /* pre-process the statistics data
1052   * - for each type, count, tot_length, min_length, max_length   * - for each type, count, tot_length, min_length, max_length
1053   * - set keyframes_locations */   * - set keyframes_locations, tot_prescaled */
1054  static void  static void
1055  first_pass_stats_prepare_data(rc_2pass2_t * rc)  first_pass_stats_prepare_data(rc_2pass2_t * rc)
1056  {  {
# Line 972  Line 1062 
1062          for (i=0; i<3; i++) {          for (i=0; i<3; i++) {
1063                  rc->count[i]=0;                  rc->count[i]=0;
1064                  rc->tot_length[i] = 0;                  rc->tot_length[i] = 0;
1065                    rc->tot_invariant[i] = 0;
1066                  rc->min_length[i] = INT_MAX;                  rc->min_length[i] = INT_MAX;
1067          }          }
1068    
1069          rc->max_length = INT_MIN;          rc->max_length = INT_MIN;
1070            rc->tot_weighted = 0;
1071    
1072          /* Loop through all frames and find/compute all the stuff this function          /* Loop through all frames and find/compute all the stuff this function
1073           * is supposed to do */           * is supposed to do */
# Line 984  Line 1076 
1076    
1077                  rc->count[s->type-1]++;                  rc->count[s->type-1]++;
1078                  rc->tot_length[s->type-1] += s->length;                  rc->tot_length[s->type-1] += s->length;
1079                    rc->tot_invariant[s->type-1] += s->invariant;
1080                    if (s->zone_mode != XVID_ZONE_QUANT)
1081                            rc->tot_weighted += (int)(s->weight*(s->length - s->invariant));
1082    
1083                  if (s->length < rc->min_length[s->type-1]) {                  if (s->length < rc->min_length[s->type-1]) {
1084                          rc->min_length[s->type-1] = s->length;                          rc->min_length[s->type-1] = s->length;
# Line 1018  Line 1113 
1113          int i,j;          int i,j;
1114          int n = 0;          int n = 0;
1115    
         rc->avg_weight = 0.0;  
1116          rc->tot_quant = 0;          rc->tot_quant = 0;
1117            rc->tot_quant_invariant = 0;
1118    
1119          if (create->num_zones == 0) {          if (create->num_zones == 0) {
1120                  for (j = 0; j < rc->num_frames; j++) {                  for (j = 0; j < rc->num_frames; j++) {
1121                          rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;                          rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1122                          rc->stats[j].weight = 1.0;                          rc->stats[j].weight = 1.0;
1123                  }                  }
                 rc->avg_weight += rc->num_frames * 1.0;  
1124                  n += rc->num_frames;                  n += rc->num_frames;
1125          }          }
1126    
# Line 1036  Line 1129 
1129    
1130                  int next = (i+1<create->num_zones) ? create->zones[i+1].frame : rc->num_frames;                  int next = (i+1<create->num_zones) ? create->zones[i+1].frame : rc->num_frames;
1131    
1132                    /* Zero weight make no sense */
1133                    if (create->zones[i].increment == 0) create->zones[i].increment = 1;
1134                    /* And obviously an undetermined infinite makes even less sense */
1135                    if (create->zones[i].base == 0) create->zones[i].base = 1;
1136    
1137                  if (i==0 && create->zones[i].frame > 0) {                  if (i==0 && create->zones[i].frame > 0) {
1138                          for (j = 0; j < create->zones[i].frame && j < rc->num_frames; j++) {                          for (j = 0; j < create->zones[i].frame && j < rc->num_frames; j++) {
1139                                  rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;                                  rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1140                                  rc->stats[j].weight = 1.0;                                  rc->stats[j].weight = 1.0;
1141                          }                          }
                         rc->avg_weight += create->zones[i].frame * 1.0;  
1142                          n += create->zones[i].frame;                          n += create->zones[i].frame;
1143                  }                  }
1144    
# Line 1051  Line 1148 
1148                                  rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;                                  rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1149                          }                          }
1150                          next -= create->zones[i].frame;                          next -= create->zones[i].frame;
                         rc->avg_weight += (double)(next * create->zones[i].increment) / (double)create->zones[i].base;  
1151                          n += next;                          n += next;
1152                  }else{  /* XVID_ZONE_QUANT */                  }else{  /* XVID_ZONE_QUANT */
1153                          for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {                          for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1154                                  rc->stats[j].zone_mode = XVID_ZONE_QUANT;                                  rc->stats[j].zone_mode = XVID_ZONE_QUANT;
1155                                  rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;                                  rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1156                                  rc->tot_quant += rc->stats[j].length;                                  rc->tot_quant += rc->stats[j].length;
1157                                    rc->tot_quant_invariant += rc->stats[j].invariant;
1158                          }                          }
1159                  }                  }
1160          }          }
         rc->avg_weight = n>0 ? rc->avg_weight/n : 1.0;  
   
         DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- center_weight:%f (for %d frames)  fixed_bytes:%d\n", rc->avg_weight, n, rc->tot_quant);  
1161  }  }
1162    
1163    
# Line 1072  Line 1166 
1166  first_pass_scale_curve_internal(rc_2pass2_t *rc)  first_pass_scale_curve_internal(rc_2pass2_t *rc)
1167  {  {
1168          int64_t target;          int64_t target;
1169          int64_t pass1_length;          int64_t total_invariant;
1170          double scaler;          double scaler;
1171          int i, num_MBs;          int i, num_MBs;
1172    
1173          /* We remove the bytes used by the fixed quantizer zones          /* We only scale texture data ! */
1174           * ToDo: this approach is flawed, the same amount of bytes is removed from          total_invariant  = rc->tot_invariant[XVID_TYPE_IVOP-1];
1175           *       target and first pass data, this has no sense, zone_process should          total_invariant += rc->tot_invariant[XVID_TYPE_PVOP-1];
1176           *       give us two results one for unscaled data (1pass) and the other          total_invariant += rc->tot_invariant[XVID_TYPE_BVOP-1];
1177           *       one for scaled data and we should then write:          /* don't forget to substract header bytes used in quant zones, otherwise we
1178           *       target = rc->target - rc->tot_quant_scaled;           * counting them twice */
1179           *       pass1_length = rc->i+p+b - rc->tot_quant_firstpass */          total_invariant -= rc->tot_quant_invariant;
1180          target = rc->target - rc->tot_quant;  
1181            /* We remove the bytes used by the fixed quantizer zones during first pass
1182          /* Do the same for the first pass data */           * with the same quants, so we know very precisely how much that
1183          pass1_length  = rc->tot_length[XVID_TYPE_IVOP-1];           * represents */
1184          pass1_length += rc->tot_length[XVID_TYPE_PVOP-1];          target  = rc->target;
1185          pass1_length += rc->tot_length[XVID_TYPE_BVOP-1];          target -= rc->tot_quant;
         pass1_length -= rc->tot_quant;  
1186    
1187          /* Let's compute a linear scaler in order to perform curve scaling */          /* Let's compute a linear scaler in order to perform curve scaling */
1188          scaler = (double)target / (double)pass1_length;          scaler = (double)(target - total_invariant) / (double)(rc->tot_weighted);
1189    
1190          if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {  #ifdef SMART_OVERFLOW_SETTING
1191                  DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected before correction\n");          if (scaler > 0.9) {
1192                  scaler = 1.0;                  rc->param.max_overflow_degradation *= 5;
1193                    rc->param.max_overflow_improvement *= 5;
1194                    rc->param.overflow_control_strength *= 3;
1195            } else if (scaler > 0.6) {
1196                    rc->param.max_overflow_degradation *= 2;
1197                    rc->param.max_overflow_improvement *= 2;
1198                    rc->param.overflow_control_strength *= 2;
1199            } else {
1200                    rc->min_quant = 2;
1201          }          }
1202    #endif
1203    
1204          /* Compute min frame lengths (for each frame type) according to the number          /* Compute min frame lengths (for each frame type) according to the number
1205           * of MBs. We sum all block type counters of frame 0, this gives us the           * of MBs. We sum all block type counters of frame 0, this gives us the
# Line 1139  Line 1241 
1241                          continue;                          continue;
1242                  }                  }
1243    
1244                  /* Compute the scaled length */                  /* Compute the scaled length -- only non invariant data length is scaled */
1245                  len = (int)((double)s->length * scaler * s->weight / rc->avg_weight);                  len = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight);
1246    
1247                  /* Compare with the computed minimum */                  /* Compare with the computed minimum */
1248                  if (len < rc->min_length[s->type-1]) {                  if (len < rc->min_length[s->type-1]) {
# Line 1152  Line 1254 
1254                           * total counters, as we prepare a second pass for 'regular'                           * total counters, as we prepare a second pass for 'regular'
1255                           * frames */                           * frames */
1256                          target -= s->scaled_length;                          target -= s->scaled_length;
                         pass1_length -= s->length;  
1257                  } else {                  } else {
1258                          /* Do nothing for now, we'll scale this later */                          /* Do nothing for now, we'll scale this later */
1259                          s->scaled_length = 0;                          s->scaled_length = 0;
# Line 1163  Line 1264 
1264           * total counters. Now, it's possible to scale the 'regular' frames. */           * total counters. Now, it's possible to scale the 'regular' frames. */
1265    
1266          /* Scaling factor for 'regular' frames */          /* Scaling factor for 'regular' frames */
1267          scaler = (double)target / (double)pass1_length;          scaler = (double)(target - total_invariant) / (double)(rc->tot_weighted);
   
         /* Detect undersizing */  
         if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {  
                 DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected after correction\n");  
                 scaler = 1.0;  
         }  
1268    
1269          /* Do another pass with the new scaler */          /* Do another pass with the new scaler */
1270          for (i=0; i<rc->num_frames; i++) {          for (i=0; i<rc->num_frames; i++) {
# Line 1177  Line 1272 
1272    
1273                  /* Ignore frame with forced frame sizes */                  /* Ignore frame with forced frame sizes */
1274                  if (s->scaled_length == 0)                  if (s->scaled_length == 0)
1275                          s->scaled_length = (int)((double)s->length * scaler * s->weight / rc->avg_weight);                          s->scaled_length = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight);
1276          }          }
1277    
1278          /* Job done */          /* Job done */
# Line 1192  Line 1287 
1287  scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)  scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)
1288  {  {
1289          int i;          int i;
1290          uint64_t ivop_boost_total;          int64_t ivop_boost_total;
1291    
1292          /* Reset the rate controller (per frame type) total byte counters */          /* Reset the rate controller (per frame type) total byte counters */
1293          for (i=0; i<3; i++) rc->tot_scaled_length[i] = 0;          for (i=0; i<3; i++) rc->tot_scaled_length[i] = 0;
# Line 1215  Line 1310 
1310    
1311                  /* Some more work is needed for I frames */                  /* Some more work is needed for I frames */
1312                  if (s->type == XVID_TYPE_IVOP) {                  if (s->type == XVID_TYPE_IVOP) {
                         int penalty_distance;  
1313                          int ivop_boost;                          int ivop_boost;
1314    
1315                          /* Accumulate bytes needed for keyframe boosting */                          /* Accumulate bytes needed for keyframe boosting */
1316                          ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;                          ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;
1317    
1318                          if (rc->KF_idx) {  #if 0 /* ToDo: decide how to apply kfthresholding */
1319                                  /* Minimum keyframe distance penalties */  #endif
                                 penalty_distance  = rc->param.min_key_interval;  
                                 penalty_distance -= rc->keyframe_locations[rc->KF_idx];  
                                 penalty_distance += rc->keyframe_locations[rc->KF_idx-1];  
   
                                 /* Ah ah ! guilty keyframe, you're under arrest ! */  
                                 if (penalty_distance > 0)  
                                          ivop_boost -= (s->scaled_length + ivop_boost)*penalty_distance*rc->param.kfreduction/100;  
                         }  
   
1320                          /* If the frame size drops under the minimum length, then cap ivop_boost */                          /* If the frame size drops under the minimum length, then cap ivop_boost */
1321                          if (ivop_boost + s->scaled_length < rc->min_length[XVID_TYPE_IVOP-1])                          if (ivop_boost + s->scaled_length < rc->min_length[XVID_TYPE_IVOP-1])
1322                                  ivop_boost = rc->min_length[XVID_TYPE_IVOP-1] - s->scaled_length;                                  ivop_boost = rc->min_length[XVID_TYPE_IVOP-1] - s->scaled_length;
# Line 1261  Line 1346 
1346    
1347          /* Compute the ratio described above          /* Compute the ratio described above
1348           *     taxed_total = sum(0, n, tax*scaled_length)           *     taxed_total = sum(0, n, tax*scaled_length)
1349           * <=> taxed_total = tax.sum(0, n, tax*scaled_length)           * <=> taxed_total = tax.sum(0, n, scaled_length)
1350           * <=> tax = taxed_total / original_total */           * <=> tax = taxed_total / original_total */
1351          rc->pb_iboost_tax_ratio =          rc->pb_iboost_tax_ratio =
1352                  (rc->pb_iboost_tax_ratio - ivop_boost_total) /                  (rc->pb_iboost_tax_ratio - ivop_boost_total) /
# Line 1278  Line 1363 
1363                  } else {                  } else {
1364                          rc->avg_length[i] = rc->tot_scaled_length[i];                          rc->avg_length[i] = rc->tot_scaled_length[i];
1365    
1366                          if (i == XVID_TYPE_IVOP) {                          if (i == (XVID_TYPE_IVOP-1)) {
1367                                  /* I Frames total has to be added the boost total */                                  /* I Frames total has to be added the boost total */
1368                                  rc->avg_length[i] += ivop_boost_total;                                  rc->avg_length[i] += ivop_boost_total;
1369                          } else {                          } else {
# Line 1355  Line 1440 
1440  }  }
1441    
1442  /*****************************************************************************  /*****************************************************************************
1443     * VBV compliancy check and scale
1444     * MPEG-4 standard specifies certain restrictions for bitrate/framesize in VBR
1445     * to enable playback on devices with limited readspeed and memory (and which
1446     * aren't...)
1447     *
1448     * DivX profiles have 2 criteria: VBV as in MPEG standard
1449     *                                a limit on peak bitrate for any 3 seconds
1450     *
1451     * But if VBV is fulfilled, peakrate is automatically fulfilled in any profile
1452     * define so far, so we check for it (for completeness) but correct only VBV
1453     *
1454     *****************************************************************************/
1455    
1456    #define VBV_COMPLIANT 0
1457    #define VBV_UNDERFLOW 1 /* video buffer runs empty */
1458    #define VBV_OVERFLOW 2  /* doesn't exist for VBR encoding */
1459    #define VBV_PEAKRATE 4  /* peak bitrate (within 3s) violated */
1460    
1461    static int
1462    check_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps)
1463    {
1464            /* We do all calculations in float, for higher accuracy,
1465             * and in bytes for convenience.
1466             *
1467             * typical values from DivX Home Theater profile:
1468             *  vbv_size= 384*1024 (384kB)
1469             *  vbv_initial= 288*1024 (75% fill)
1470             *  maxrate= 4854000 (4.854MBps)
1471             *  peakrate= 8000000 (8MBps)
1472             *
1473             *  PAL: offset3s = 75 (3 seconds of 25fps)
1474             *  NTSC: offset3s = 90 (3 seconds of 29.97fps) or 72 (3 seconds of 23.976fps)
1475             */
1476    
1477            const float vbv_size = (float)rc->param.vbv_size/8.f;
1478            float vbvfill = (float)rc->param.vbv_initial/8.f;
1479            float vbvmin;
1480    
1481            const float maxrate = (float)rc->param.vbv_maxrate;
1482            const float peakrate = (float)rc->param.vbv_peakrate;
1483            const float r0 = (int)(maxrate/fps+0.5)/8.f;
1484    
1485            int bytes3s = 0;
1486            int offset3s = (int)(3.f*fps+0.5);
1487            int i;
1488    
1489            /* 1Gbit should be enough to inuitialize the vbvmin
1490             *      an arbitrary high value */
1491            vbvmin = 1000*1000*1000;
1492    
1493            for (i=0; i<rc->num_frames; i++) {
1494                    /* DivX 3s peak bitrate check  */
1495                    bytes3s += rc->stats[i].scaled_length;
1496                    if (i>=offset3s)
1497                            bytes3s -= rc->stats[i-offset3s].scaled_length;
1498    
1499        /* ignore peakrate constraint if peakrate is <= 0.f */
1500                    if (peakrate>0.f && 8.f*bytes3s > 3*peakrate)
1501                            return(VBV_PEAKRATE);
1502    
1503                    /* update vbv fill level */
1504                    vbvfill += r0 - rc->stats[i].scaled_length;
1505    
1506                    /* this check is _NOT_ an "overflow"! only reading from disk stops then */
1507                    if (vbvfill > vbv_size)
1508                            vbvfill = vbv_size;
1509    
1510                    /* but THIS would be an underflow. report it! */
1511                    if (vbvfill < 0)
1512                            return(VBV_UNDERFLOW);
1513    
1514                    /* Store the minimum buffer filling */
1515                    if (vbvfill < vbvmin)
1516                            vbvmin = vbvfill;
1517            }
1518    
1519            DPRINTF(XVID_DEBUG_RC, "[xvid rc] Minimum buffer fill: %f bytes\n", vbvmin);
1520    
1521            return(VBV_COMPLIANT);
1522    }
1523    
1524    
1525    static int
1526    scale_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps)
1527    {
1528            /* correct any VBV violations. Peak bitrate violations disappears
1529             * by this automatically
1530             *
1531             * This implementation follows
1532             *
1533             * Westerink, Rajagopalan, Gonzales "Two-pass MPEG-2 variable-bitrate encoding"
1534             * IBM J. RES. DEVELOP. VOL 43, No. 4, July 1999, p.471--488
1535             *
1536             * Thanks, guys! This paper rocks!!! */
1537    
1538            /* For each scene of len N, we have to check up to N^2 possible buffer fills.
1539             * This works well with MPEG-2 where N==12 or so, but for MPEG-4 it's a
1540             * little slow...
1541             *
1542             * TODO: Better control on VBVfill between scenes */
1543    
1544            const float vbv_size = (float)rc->param.vbv_size/8.f;
1545            const float vbv_initial = (float)rc->param.vbv_initial/8.f;
1546    
1547            const float maxrate = 0.9*rc->param.vbv_maxrate;
1548            const float vbv_low = 0.10f*vbv_size;
1549            const float r0 = (int)(maxrate/fps+0.5)/8.f;
1550    
1551            int i,k,l,n,violation = 0;
1552            float *scenefactor;
1553            int *scenestart;
1554            int *scenelength;
1555    
1556            /* first step: determine how many "scenes" there are and store their
1557             * boundaries we could get all this from existing keyframe_positions,
1558             * somehow, but there we don't have a min_scenelength, and it's no big
1559             * deal to get it again. */
1560    
1561            const int min_scenelength = (int)(fps+0.5);
1562            int num_scenes = 0;
1563            int last_scene = -999;
1564            for (i=0; i<rc->num_frames; i++) {
1565                    if ((rc->stats[i].type == XVID_TYPE_IVOP) && (i-last_scene>min_scenelength)) {
1566                            last_scene = i;
1567                            num_scenes++;
1568                    }
1569            }
1570    
1571            scenefactor = (float*)malloc(num_scenes*sizeof(float));
1572            scenestart = (int*)malloc(num_scenes*sizeof(int));
1573            scenelength = (int*)malloc(num_scenes*sizeof(int));
1574    
1575            if ((!scenefactor) || (!scenestart) || (!scenelength) ) {
1576                    free(scenefactor);
1577                    free(scenestart);
1578                    free(scenelength);
1579                    /* remember: free(0) is valid and does exactly nothing. */
1580                    return(-1);
1581            }
1582    
1583            /* count again and safe the length/position */
1584    
1585            num_scenes = 0;
1586            last_scene = -999;
1587            for (i=0; i<rc->num_frames; i++) {
1588                    if ((rc->stats[i].type == XVID_TYPE_IVOP) && (i-last_scene>min_scenelength)) {
1589                            if (num_scenes>0) {
1590                                    scenelength[num_scenes-1]=i-last_scene;
1591                            }
1592                            scenestart[num_scenes]=i;
1593                            num_scenes++;
1594                            last_scene = i;
1595                    }
1596            }
1597            scenelength[num_scenes-1]=i-last_scene;
1598    
1599            /* second step: check for each scene, how much we can scale its frames up or
1600             * down such that the VBV restriction is just fulfilled */
1601    #define R(k,n) (((n)+1-(k))*r0)     /* how much enters the buffer between frame k and n */
1602            for (l=0; l<num_scenes;l++) {
1603                    const int start = scenestart[l];
1604                    const int length = scenelength[l];
1605                    twopass_stat_t * frames = &rc->stats[start];
1606    
1607                    float S0n,Skn;
1608                    float f,minf = 99999.f;
1609    
1610                    S0n=0.;
1611                    for (n=0;n<=length-1;n++) {
1612                            S0n += frames[n].scaled_length;
1613    
1614                            k = 0;
1615                            Skn = S0n;
1616                            f = (R(k,n-1) + (vbv_initial - vbv_low)) / Skn;
1617                            if (f < minf)
1618                                    minf = f;
1619    
1620                            for (k=1;k<=n;k++) {
1621                                    Skn -= frames[k].scaled_length;
1622    
1623                                    f = (R(k,n-1) + (vbv_size - vbv_low)) / Skn;
1624                                    if (f < minf)
1625                                            minf = f;
1626                            }
1627                    }
1628    
1629                    /* special case: at the end, fill buffer up to vbv_initial again
1630                     *
1631                     * TODO: Allow other values for buffer fill between scenes
1632                     * e.g. if n=N is smallest f-value, then check for better value */
1633    
1634                    n=length;
1635                    k=0;
1636                    Skn = S0n;
1637                    f = R(k,n-1)/Skn;
1638                    if (f < minf)
1639                            minf = f;
1640    
1641                    for (k=1;k<=n-1;k++) {
1642                            Skn -= frames[k].scaled_length;
1643    
1644                            f = (R(k,n-1) + (vbv_initial - vbv_low)) / Skn;
1645                            if (f < minf)
1646                                    minf = f;
1647                    }
1648    
1649                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] Scene %d (Frames %d-%d): VBVfactor %f\n",
1650                                    l, start, start+length-1 , minf);
1651    
1652                    scenefactor[l] = minf;
1653            }
1654    #undef R
1655    
1656            /* last step: now we know of any scene how much it can be scaled up or down
1657             * without violating VBV. Next, distribute bits from the evil scenes to the
1658             * good ones */
1659            do {
1660                    float S_red = 0.f;    /* how much to redistribute */
1661                    float S_elig = 0.f;   /* sum of bit for those scenes you can still swallow something*/
1662                    float f_red;
1663                    int l;
1664    
1665                    /* check how much is wrong */
1666                    for (l=0;l<num_scenes;l++) {
1667                            const int start = scenestart[l];
1668                            const int length = scenelength[l];
1669                            twopass_stat_t * frames = &rc->stats[start];
1670    
1671                            /* exactly 1 means "don't touch this anymore!" */
1672                            if (scenefactor[l] == 1.)
1673                                    continue;
1674    
1675                            /* within limits */
1676                            if (scenefactor[l] > 1.) {
1677                                    for (n= 0; n < length; n++)
1678                                            S_elig += frames[n].scaled_length;
1679                            } else {
1680                                    /* underflowing segment */
1681                                    for (n= 0; n < length; n++) {
1682                                            float newbytes = (float)frames[n].scaled_length * scenefactor[l];
1683                                            S_red += (float)frames[n].scaled_length - (float)newbytes;
1684                                            frames[n].scaled_length =(int)newbytes;
1685                                    }
1686                                    scenefactor[l] = 1.f;
1687                            }
1688                    }
1689    
1690                    /* no more underflows */
1691                    if (S_red < 1.f)
1692                            break;
1693    
1694                    if (S_elig < 1.f) {
1695                            DPRINTF(XVID_DEBUG_RC, "[xvid rc] Everything underflowing.\n");
1696                            free(scenefactor);
1697                            free(scenestart);
1698                            free(scenelength);
1699                            return(-2);
1700                    }
1701    
1702                    f_red = (1.f + S_red/S_elig);
1703    
1704                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] Moving %.0f kB to avoid buffer underflow, correction factor: %.5f\n",
1705                                    S_red/1024.f, f_red);
1706    
1707                    violation=0;
1708                    /* scale remaining scenes up to meet total size */
1709                    for (l=0; l<num_scenes; l++) {
1710                            const int start = scenestart[l];
1711                            const int length = scenelength[l];
1712                            twopass_stat_t * frames = &rc->stats[start];
1713    
1714                            if (scenefactor[l] == 1.)
1715                                    continue;
1716    
1717                            /* there shouldn't be any segments with factor<1 left, so all the rest is >1 */
1718                            for (n= 0; n < length; n++) {
1719                                    frames[n].scaled_length = (int)(frames[n].scaled_length * f_red + 0.5);
1720                            }
1721    
1722                            scenefactor[l] /= f_red;
1723                            if (scenefactor[l] < 1.f)
1724                                    violation=1;
1725                    }
1726    
1727            } while (violation);
1728    
1729            free(scenefactor);
1730            free(scenestart);
1731            free(scenelength);
1732            return(0);
1733    }
1734    
1735    
1736    /*****************************************************************************
1737   * Still more low level stuff (nothing to do with stats treatment)   * Still more low level stuff (nothing to do with stats treatment)
1738   ****************************************************************************/   ****************************************************************************/
1739    

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