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Diff of /xvidcore/src/plugins/plugin_2pass2.c

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revision 1.1.2.24, Sun Nov 9 20:49:21 2003 UTC revision 1.6, Sun Jan 9 20:26:42 2005 UTC
# 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           *--------------------------------*/           *--------------------------------*/
# Line 220  Line 240 
240  {  {
241          switch(opt) {          switch(opt) {
242          case XVID_PLG_INFO :          case XVID_PLG_INFO :
243            case XVID_PLG_FRAME :
244                  return 0;                  return 0;
245    
246          case XVID_PLG_CREATE :          case XVID_PLG_CREATE :
# Line 249  Line 270 
270  static void first_pass_stats_prepare_data(rc_2pass2_t * rc);  static void first_pass_stats_prepare_data(rc_2pass2_t * rc);
271  static void first_pass_scale_curve_internal(rc_2pass2_t *rc);  static void first_pass_scale_curve_internal(rc_2pass2_t *rc);
272  static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);  static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);
273    static  int check_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps);
274    static  int scale_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps);
275  #if 0  #if 0
276  static void stats_print(rc_2pass2_t * rc);  static void stats_print(rc_2pass2_t * rc);
277  #endif  #endif
# Line 267  Line 290 
290          if (rc == NULL)          if (rc == NULL)
291                  return XVID_ERR_MEMORY;                  return XVID_ERR_MEMORY;
292    
293          rc->param = *param;          /* v1.0.x */
294            rc->param.version = param->version;
295            rc->param.bitrate = param->bitrate;
296            rc->param.filename = param->filename;
297            rc->param.keyframe_boost = param->keyframe_boost;
298            rc->param.curve_compression_high = param->curve_compression_high;
299            rc->param.curve_compression_low = param->curve_compression_low;
300            rc->param.overflow_control_strength = param->overflow_control_strength;
301            rc->param.max_overflow_improvement = param->max_overflow_improvement;
302            rc->param.max_overflow_degradation = param->max_overflow_degradation;
303            rc->param.kfreduction = param->kfreduction;
304            rc->param.kfthreshold = param->kfthreshold;
305            rc->param.container_frame_overhead = param->container_frame_overhead;
306    
307            if (XVID_VERSION_MINOR(param->version) >= 1) {
308                    rc->param.vbv_size = param->vbv_size;
309                    rc->param.vbv_initial = param->vbv_initial;
310                    rc->param.vbv_maxrate = param->vbv_maxrate;
311                    rc->param.vbv_peakrate = param->vbv_peakrate;
312            }else{
313                    rc->param.vbv_size =
314                    rc->param.vbv_initial =
315                    rc->param.vbv_maxrate =
316                    rc->param.vbv_peakrate = 0;
317            }
318    
319          /* Initialize all defaults */          /* Initialize all defaults */
320  #define _INIT(a, b) if((a) <= 0) (a) = (b)  #define _INIT(a, b) if((a) <= 0) (a) = (b)
# Line 281  Line 328 
328    
329          /* Keyframe settings */          /* Keyframe settings */
330          _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);          _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);
331          _INIT(rc->param.min_key_interval, DEFAULT_MIN_KEY_INTERVAL);          _INIT(rc->param.kfthreshold, DEFAULT_KFTHRESHOLD);
332  #undef _INIT  #undef _INIT
333    
334          /* Initialize some stuff to zero */          /* Initialize some stuff to zero */
# Line 296  Line 343 
343          for (i=0; i<3; i++) rc->last_quant[i] = 0;          for (i=0; i<3; i++) rc->last_quant[i] = 0;
344    
345          rc->fq_error = 0;          rc->fq_error = 0;
346            rc->min_quant = 1;
347    
348          /* 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
349           * the rc structure */           * the rc structure */
# Line 332  Line 380 
380          /* Compute the target filesize */          /* Compute the target filesize */
381          if (rc->param.bitrate<0) {          if (rc->param.bitrate<0) {
382                  /* if negative, bitrate equals the target (in kbytes) */                  /* if negative, bitrate equals the target (in kbytes) */
383                  rc->target = (-rc->param.bitrate) * 1024;                  rc->target = ((uint64_t)(-rc->param.bitrate)) * 1024;
384          } else if (rc->num_frames  < create->fbase/create->fincr) {          } else if (rc->num_frames  < create->fbase/create->fincr) {
385                  /* 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 */
386                  rc->target = rc->param.bitrate / 8;                  rc->target = rc->param.bitrate / 8;
# Line 358  Line 406 
406          if(rc->param.container_frame_overhead)          if(rc->param.container_frame_overhead)
407                  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);
408    
409            /* When bitrate is not given it means it has been scaled by an external
410             * application */
411            if (rc->param.bitrate) {
412                    /* Apply zone settings
413                     * - set rc->tot_quant which represents the total num of bytes spent in
414                     *   fixed quant zones
415                     * - set rc->tot_weighted which represents the total amount of bytes
416                     *   spent in normal or weighted zones in first pass (normal zones can
417                     *   be considered weight=1)
418                     * - set rc->tot_quant_invariant which represents the total num of bytes
419                     *   spent in fixed quant zones for headers */
420                    zone_process(rc, create);
421            } else {
422                    /* External scaling -- zones are ignored */
423                    for (i=0;i<rc->num_frames;i++) {
424                            rc->stats[i].zone_mode = XVID_ZONE_WEIGHT;
425                            rc->stats[i].weight = 1.0;
426                    }
427                    rc->tot_quant = 0;
428            }
429    
430          /* Gathers some information about first pass stats:          /* Gathers some information about first pass stats:
431           *  - finds the minimum frame length for each frame type during 1st pass.           *  - finds the minimum frame length for each frame type during 1st pass.
432           *     rc->min_size[]           *     rc->min_size[]
# Line 366  Line 435 
435           *  - count how many times each frame type has been used.           *  - count how many times each frame type has been used.
436           *     rc->count[]           *     rc->count[]
437           *  - total bytes used per frame type           *  - total bytes used per frame type
438           *     rc->total[]           *     rc->tot_length[]
439             *  - total bytes considered invariant between the 2 passes
440           *  - store keyframe location           *  - store keyframe location
441           *     rc->keyframe_locations[]           *     rc->keyframe_locations[]
442           */           */
443          first_pass_stats_prepare_data(rc);          first_pass_stats_prepare_data(rc);
444    
445          /* 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 */  
446          if (rc->param.bitrate) {          if (rc->param.bitrate) {
                 /* Apply zone settings */  
                 zone_process(rc, create);  
447                  /* Perform internal curve scaling */                  /* Perform internal curve scaling */
448                  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;  
449          }          }
450    
451          /* Apply advanced curve options, and compute some parameters in order to          /* Apply advanced curve options, and compute some parameters in order to
452           * shape the curve in the BEFORE/AFTER pair of functions */           * shape the curve in the BEFORE/AFTER pair of functions */
453          scaled_curve_apply_advanced_parameters(rc);          scaled_curve_apply_advanced_parameters(rc);
454    
455            /* Check curve for VBV compliancy and rescale if necessary */
456    #ifdef VBV_FORCE
457            if (rc->param.vbv_size==0) {
458                    rc->param.vbv_size      =  3145728;
459                    rc->param.vbv_initial   =  2359296;
460                    rc->param.vbv_maxrate  =  4000000;
461                    rc->param.vbv_peakrate = 10000000;
462            }
463    #endif
464    
465            /* vbv_size==0 switches VBV check off */
466            if (rc->param.vbv_size > 0)  {
467                    const double fps = (double)create->fbase/(double)create->fincr;
468                    int status = check_curve_for_vbv_compliancy(rc, fps);
469    
470                    if (status) {
471                            DPRINTF(XVID_DEBUG_RC, "[xvid rc] Underflow detected - Scaling Curve for compliancy.\n");
472                    }
473    
474                    status = scale_curve_for_vbv_compliancy(rc, fps);
475    
476                    if (status == 0) {
477                            DPRINTF(XVID_DEBUG_RC, "[xvid rc] VBV compliant curve scaling done.\n");
478                    } else {
479                            DPRINTF(XVID_DEBUG_RC, "[xvid rc] VBV compliant curve scaling impossible.\n");
480                    }
481            }
482          *handle = rc;          *handle = rc;
483          return(0);          return(0);
484  }  }
# Line 435  Line 521 
521          if (data->quant > 0)          if (data->quant > 0)
522                  return(0);                  return(0);
523    
524          /* Second case: We are in a Quant zone */          /* Second case: insufficent stats data
525             * We can't guess much what we should do, let core decide all alone */
526            if (data->frame_num >= rc->num_frames) {
527                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- stats file too short (now processing frame %d)",
528                            data->frame_num);
529                    return(0);
530            }
531    
532            /* Third case: We are in a Quant zone
533             * Quant zones must just ensure we use the same settings as first pass
534             * So set the quantizer and the type */
535          if (s->zone_mode == XVID_ZONE_QUANT) {          if (s->zone_mode == XVID_ZONE_QUANT) {
536                    /* Quant stuff */
537                  rc->fq_error += s->weight;                  rc->fq_error += s->weight;
538                  data->quant = (int)rc->fq_error;                  data->quant = (int)rc->fq_error;
539                  rc->fq_error -= data->quant;                  rc->fq_error -= data->quant;
540    
541                    /* The type stuff */
542                    data->type = s->type;
543    
544                    /* The only required data for AFTER step is this one for the overflow
545                     * control */
546                  s->desired_length = s->length;                  s->desired_length = s->length;
547    
548                  return(0);                  return(0);
549          }          }
550    
         /* Third case: insufficent stats data */  
         if (data->frame_num >= rc->num_frames)  
                 return(0);  
551    
552          /*************************************************************************/          /*************************************************************************/
553          /*************************************************************************/          /*************************************************************************/
# Line 466  Line 565 
565    
566          /* IFrame user settings*/          /* IFrame user settings*/
567          if (s->type == XVID_TYPE_IVOP) {          if (s->type == XVID_TYPE_IVOP) {
   
568                  /* Keyframe boosting -- All keyframes benefit from it */                  /* Keyframe boosting -- All keyframes benefit from it */
569                  dbytes += dbytes*rc->param.keyframe_boost / 100;                  dbytes += dbytes*rc->param.keyframe_boost / 100;
570    
571                  /* Applies keyframe penalties, but not the first frame */  #if 0 /* ToDo: decide how to apply kfthresholding */
572                  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;  
                 }  
573          } else {          } else {
574    
575                  /* 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 611 
611           *-----------------------------------------------------------------------*/           *-----------------------------------------------------------------------*/
612    
613          /* Compute the overflow we should compensate */          /* Compute the overflow we should compensate */
614          if (s->type != XVID_TYPE_IVOP) {          if (s->type != XVID_TYPE_IVOP || rc->overflow > 0) {
615                  double frametype_factor;                  double frametype_factor;
616                  double framesize_factor;                  double framesize_factor;
617    
# Line 555  Line 642 
642                  /* Apply the overflow strength imposed by the user */                  /* Apply the overflow strength imposed by the user */
643                  overflow *= (rc->param.overflow_control_strength/100.0f);                  overflow *= (rc->param.overflow_control_strength/100.0f);
644          } else {          } else {
645                  /* no overflow applied in IFrames because:                  /* no negative overflow applied in IFrames because:
646                   *  - their role is important as they're references for P/BFrames.                   *  - their role is important as they're references for P/BFrames.
647                   *  - 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
648                   *    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 674 
674           * pass nor smaller than the allowed minimum.           * pass nor smaller than the allowed minimum.
675           *-----------------------------------------------------------------------*/           *-----------------------------------------------------------------------*/
676    
677    #ifdef PASS_SMALLER
678          if (dbytes > s->length) {          if (dbytes > s->length) {
679                  dbytes = s->length;                  dbytes = s->length;
680          } else if (dbytes < rc->min_length[s->type-1]) {          }
681    #endif
682    
683            /* Prevent stupid desired sizes under logical values */
684            if (dbytes < rc->min_length[s->type-1]) {
685                  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);  
686          }          }
687    
688          /*------------------------------------------------------------------------          /*------------------------------------------------------------------------
689           * Desired frame length <-> quantizer mapping           * Desired frame length <-> quantizer mapping
690           *-----------------------------------------------------------------------*/           *-----------------------------------------------------------------------*/
691    
692          /* For bframes we must retrieve the original quant used (sent to xvidcore)  #ifdef BQUANT_PRESCALE
693           * as core applies the bquant formula before writing the stat log entry */          /* For bframes we prescale the quantizer to avoid too high quant scaling */
694          if(s->type == XVID_TYPE_BVOP) {          if(s->type == XVID_TYPE_BVOP) {
695    
696                  twopass_stat_t *b_ref = s;                  twopass_stat_t *b_ref = s;
# Line 616  Line 700 
700                          b_ref--;                          b_ref--;
701    
702                  /* Compute the original quant */                  /* Compute the original quant */
703                  s->quant  = 100*s->quant - data->bquant_offset;                  s->quant  = 2*(100*s->quant - data->bquant_offset);
704                  s->quant += data->bquant_ratio - 1; /* to avoid rouding issues */                  s->quant += data->bquant_ratio - 1; /* to avoid rounding issues */
705                  s->quant  = s->quant/data->bquant_ratio - b_ref->quant;                  s->quant  = s->quant/data->bquant_ratio - b_ref->quant;
706          }          }
707    #endif
708    
709          /* Don't laugh at this very 'simple' quant<->filesize relationship, it          /* Don't laugh at this very 'simple' quant<->size relationship, it
710           * proves to be acurate enough for our algorithm */           * proves to be acurate enough for our algorithm */
711          scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;          scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;
712    
# Line 682  Line 767 
767                  data->quant = data->max_quant[s->type-1];                  data->quant = data->max_quant[s->type-1];
768          }          }
769    
770            if (data->quant < rc->min_quant) data->quant = rc->min_quant;
771    
772          /* 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"
773           * rule that makes |last_quant - new_quant| <= 2. This rule only applies           * rule that makes |last_quant - new_quant| <= 2. This rule only applies
774           * to predicted frames (P and B) */           * to predicted frames (P and B) */
# Line 709  Line 796 
796          /* Don't forget to force 1st pass frame type ;-) */          /* Don't forget to force 1st pass frame type ;-) */
797          data->type = s->type;          data->type = s->type;
798    
         /* Store the quantizer into the statistics -- Used to compensate the double  
          * formula symptom */  
         s->quant2 = data->quant;  
   
799          return 0;          return 0;
800  }  }
801    
# Line 774  Line 857 
857                  rc->KFoverflow -= rc->KFoverflow_partial;                  rc->KFoverflow -= rc->KFoverflow_partial;
858          }          }
859    
860          rc->overflow += s->error = s->desired_length - data->length;          s->error = s->desired_length - data->length;
861          rc->real_total += data->length;          rc->real_total += data->length;
862    
863          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 906 
906    
907                  char *ptr;                  char *ptr;
908                  char type;                  char type;
909                  int fields, nouse;                  int fields;
910    
911                  lines++;                  lines++;
912    
913                  /* We skip spaces */                  /* We skip spaces */
914                  ptr = skipspaces(line);                  ptr = skipspaces(line);
915    
916                  /* Skip coment lines */                  /* Skip coment lines or empty lines */
917                  if(iscomment(ptr)) {                  if(iscomment(ptr) || *ptr == '\0') {
918                          free(line);                          free(line);
919                          continue;                          continue;
920                  }                  }
921    
922                  /* Read the stat line from buffer */                  /* Read the stat line from buffer */
923                  fields = sscanf(ptr,                  fields = sscanf(ptr, "%c", &type);
                                                 "%c %d %d %d %d %d",  
                                                 &type, &nouse, &nouse, &nouse, &nouse, &nouse);  
924    
925                  /* Valid stats files have at least 6 fields */                  /* Valid stats files have at least 7 fields */
926                  if (fields == 6) {                  if (fields == 1) {
927                          switch(type) {                          switch(type) {
928                          case 'i':                          case 'i':
929                          case 'I':                          case 'I':
# Line 863  Line 944 
944                  } else {                  } else {
945                                  DPRINTF(XVID_DEBUG_RC,                                  DPRINTF(XVID_DEBUG_RC,
946                                                  "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",                                                  "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",
947                                                  lines, 6-fields);                                                  lines, 7-fields);
948                  }                  }
949    
950                  /* Free the line buffer */                  /* Free the line buffer */
# Line 901  Line 982 
982                  /* We skip spaces */                  /* We skip spaces */
983                  ptr = skipspaces(line);                  ptr = skipspaces(line);
984    
985                  /* Skip comment lines */                  /* Skip comment lines or empty lines */
986                  if(iscomment(ptr)) {                  if(iscomment(ptr) || *ptr == '\0') {
987                          free(line);                          free(line);
988                          continue;                          continue;
989                  }                  }
# Line 912  Line 993 
993    
994                  /* Convert the fields */                  /* Convert the fields */
995                  fields = sscanf(ptr,                  fields = sscanf(ptr,
996                                                  "%c %d %d %d %d %d %d\n",                                                  "%c %d %d %d %d %d %d %d\n",
997                                                  &type,                                                  &type,
998                                                  &s->quant,                                                  &s->quant,
999                                                  &s->blks[0], &s->blks[1], &s->blks[2],                                                  &s->blks[0], &s->blks[1], &s->blks[2],
1000                                                  &s->length,                                                  &s->length, &s->invariant /* not really yet */,
1001                                                  &s->scaled_length);                                                  &s->scaled_length);
1002    
1003                  /* Free line buffer, we don't need it anymore */                  /* Free line buffer, we don't need it anymore */
# Line 924  Line 1005 
1005    
1006                  /* Fail silently, this has probably been warned in                  /* Fail silently, this has probably been warned in
1007                   * statsfile_count_frames */                   * statsfile_count_frames */
1008                  if(fields != 6 && fields != 7)                  if(fields != 7 && fields != 8)
1009                          continue;                          continue;
1010    
1011                  /* Convert frame type */                  /* Convert frame type and compute the invariant length part */
1012                  switch(type) {                  switch(type) {
1013                  case 'i':                  case 'i':
1014                  case 'I':                  case 'I':
1015                          s->type = XVID_TYPE_IVOP;                          s->type = XVID_TYPE_IVOP;
1016                            s->invariant /= INVARIANT_HEADER_PART_IVOP;
1017                          break;                          break;
1018                  case 'p':                  case 'p':
1019                  case 'P':                  case 'P':
1020                  case 's':                  case 's':
1021                  case 'S':                  case 'S':
1022                          s->type = XVID_TYPE_PVOP;                          s->type = XVID_TYPE_PVOP;
1023                            s->invariant /= INVARIANT_HEADER_PART_PVOP;
1024                          break;                          break;
1025                  case 'b':                  case 'b':
1026                  case 'B':                  case 'B':
1027                          s->type = XVID_TYPE_BVOP;                          s->type = XVID_TYPE_BVOP;
1028                            s->invariant /= INVARIANT_HEADER_PART_BVOP;
1029                          break;                          break;
1030                  default:                  default:
1031                          /* Same as before, fail silently */                          /* Same as before, fail silently */
# Line 960  Line 1044 
1044    
1045  /* pre-process the statistics data  /* pre-process the statistics data
1046   * - for each type, count, tot_length, min_length, max_length   * - for each type, count, tot_length, min_length, max_length
1047   * - set keyframes_locations */   * - set keyframes_locations, tot_prescaled */
1048  static void  static void
1049  first_pass_stats_prepare_data(rc_2pass2_t * rc)  first_pass_stats_prepare_data(rc_2pass2_t * rc)
1050  {  {
# Line 972  Line 1056 
1056          for (i=0; i<3; i++) {          for (i=0; i<3; i++) {
1057                  rc->count[i]=0;                  rc->count[i]=0;
1058                  rc->tot_length[i] = 0;                  rc->tot_length[i] = 0;
1059                    rc->tot_invariant[i] = 0;
1060                  rc->min_length[i] = INT_MAX;                  rc->min_length[i] = INT_MAX;
1061          }          }
1062    
1063          rc->max_length = INT_MIN;          rc->max_length = INT_MIN;
1064            rc->tot_weighted = 0;
1065    
1066          /* Loop through all frames and find/compute all the stuff this function          /* Loop through all frames and find/compute all the stuff this function
1067           * is supposed to do */           * is supposed to do */
# Line 984  Line 1070 
1070    
1071                  rc->count[s->type-1]++;                  rc->count[s->type-1]++;
1072                  rc->tot_length[s->type-1] += s->length;                  rc->tot_length[s->type-1] += s->length;
1073                    rc->tot_invariant[s->type-1] += s->invariant;
1074                    if (s->zone_mode != XVID_ZONE_QUANT)
1075                            rc->tot_weighted += (int)(s->weight*(s->length - s->invariant));
1076    
1077                  if (s->length < rc->min_length[s->type-1]) {                  if (s->length < rc->min_length[s->type-1]) {
1078                          rc->min_length[s->type-1] = s->length;                          rc->min_length[s->type-1] = s->length;
# Line 1018  Line 1107 
1107          int i,j;          int i,j;
1108          int n = 0;          int n = 0;
1109    
         rc->avg_weight = 0.0;  
1110          rc->tot_quant = 0;          rc->tot_quant = 0;
1111            rc->tot_quant_invariant = 0;
1112    
1113          if (create->num_zones == 0) {          if (create->num_zones == 0) {
1114                  for (j = 0; j < rc->num_frames; j++) {                  for (j = 0; j < rc->num_frames; j++) {
1115                          rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;                          rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1116                          rc->stats[j].weight = 1.0;                          rc->stats[j].weight = 1.0;
1117                  }                  }
                 rc->avg_weight += rc->num_frames * 1.0;  
1118                  n += rc->num_frames;                  n += rc->num_frames;
1119          }          }
1120    
# Line 1036  Line 1123 
1123    
1124                  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;
1125    
1126                    /* Zero weight make no sense */
1127                    if (create->zones[i].increment == 0) create->zones[i].increment = 1;
1128                    /* And obviously an undetermined infinite makes even less sense */
1129                    if (create->zones[i].base == 0) create->zones[i].base = 1;
1130    
1131                  if (i==0 && create->zones[i].frame > 0) {                  if (i==0 && create->zones[i].frame > 0) {
1132                          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++) {
1133                                  rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;                                  rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1134                                  rc->stats[j].weight = 1.0;                                  rc->stats[j].weight = 1.0;
1135                          }                          }
                         rc->avg_weight += create->zones[i].frame * 1.0;  
1136                          n += create->zones[i].frame;                          n += create->zones[i].frame;
1137                  }                  }
1138    
# Line 1051  Line 1142 
1142                                  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;
1143                          }                          }
1144                          next -= create->zones[i].frame;                          next -= create->zones[i].frame;
                         rc->avg_weight += (double)(next * create->zones[i].increment) / (double)create->zones[i].base;  
1145                          n += next;                          n += next;
1146                  }else{  /* XVID_ZONE_QUANT */                  }else{  /* XVID_ZONE_QUANT */
1147                          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++ ) {
1148                                  rc->stats[j].zone_mode = XVID_ZONE_QUANT;                                  rc->stats[j].zone_mode = XVID_ZONE_QUANT;
1149                                  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;
1150                                  rc->tot_quant += rc->stats[j].length;                                  rc->tot_quant += rc->stats[j].length;
1151                                    rc->tot_quant_invariant += rc->stats[j].invariant;
1152                          }                          }
1153                  }                  }
1154          }          }
         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);  
1155  }  }
1156    
1157    
# Line 1072  Line 1160 
1160  first_pass_scale_curve_internal(rc_2pass2_t *rc)  first_pass_scale_curve_internal(rc_2pass2_t *rc)
1161  {  {
1162          int64_t target;          int64_t target;
1163          int64_t pass1_length;          int64_t total_invariant;
1164          double scaler;          double scaler;
1165          int i, num_MBs;          int i, num_MBs;
1166    
1167          /* We remove the bytes used by the fixed quantizer zones          /* We only scale texture data ! */
1168           * ToDo: this approach is flawed, the same amount of bytes is removed from          total_invariant  = rc->tot_invariant[XVID_TYPE_IVOP-1];
1169           *       target and first pass data, this has no sense, zone_process should          total_invariant += rc->tot_invariant[XVID_TYPE_PVOP-1];
1170           *       give us two results one for unscaled data (1pass) and the other          total_invariant += rc->tot_invariant[XVID_TYPE_BVOP-1];
1171           *       one for scaled data and we should then write:          /* don't forget to substract header bytes used in quant zones, otherwise we
1172           *       target = rc->target - rc->tot_quant_scaled;           * counting them twice */
1173           *       pass1_length = rc->i+p+b - rc->tot_quant_firstpass */          total_invariant -= rc->tot_quant_invariant;
1174          target = rc->target - rc->tot_quant;  
1175            /* We remove the bytes used by the fixed quantizer zones during first pass
1176          /* Do the same for the first pass data */           * with the same quants, so we know very precisely how much that
1177          pass1_length  = rc->tot_length[XVID_TYPE_IVOP-1];           * represents */
1178          pass1_length += rc->tot_length[XVID_TYPE_PVOP-1];          target  = rc->target;
1179          pass1_length += rc->tot_length[XVID_TYPE_BVOP-1];          target -= rc->tot_quant;
         pass1_length -= rc->tot_quant;  
1180    
1181          /* Let's compute a linear scaler in order to perform curve scaling */          /* Let's compute a linear scaler in order to perform curve scaling */
1182          scaler = (double)target / (double)pass1_length;          scaler = (double)(target - total_invariant) / (double)(rc->tot_weighted);
1183    
1184          if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {  #ifdef SMART_OVERFLOW_SETTING
1185                  DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected before correction\n");          if (scaler > 0.9) {
1186                  scaler = 1.0;                  rc->param.max_overflow_degradation *= 5;
1187                    rc->param.max_overflow_improvement *= 5;
1188                    rc->param.overflow_control_strength *= 3;
1189            } else if (scaler > 0.6) {
1190                    rc->param.max_overflow_degradation *= 2;
1191                    rc->param.max_overflow_improvement *= 2;
1192                    rc->param.overflow_control_strength *= 2;
1193            } else {
1194                    rc->min_quant = 2;
1195          }          }
1196    #endif
1197    
1198          /* Compute min frame lengths (for each frame type) according to the number          /* Compute min frame lengths (for each frame type) according to the number
1199           * 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 1235 
1235                          continue;                          continue;
1236                  }                  }
1237    
1238                  /* Compute the scaled length */                  /* Compute the scaled length -- only non invariant data length is scaled */
1239                  len = (int)((double)s->length * scaler * s->weight / rc->avg_weight);                  len = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight);
1240    
1241                  /* Compare with the computed minimum */                  /* Compare with the computed minimum */
1242                  if (len < rc->min_length[s->type-1]) {                  if (len < rc->min_length[s->type-1]) {
# Line 1152  Line 1248 
1248                           * total counters, as we prepare a second pass for 'regular'                           * total counters, as we prepare a second pass for 'regular'
1249                           * frames */                           * frames */
1250                          target -= s->scaled_length;                          target -= s->scaled_length;
                         pass1_length -= s->length;  
1251                  } else {                  } else {
1252                          /* Do nothing for now, we'll scale this later */                          /* Do nothing for now, we'll scale this later */
1253                          s->scaled_length = 0;                          s->scaled_length = 0;
# Line 1163  Line 1258 
1258           * total counters. Now, it's possible to scale the 'regular' frames. */           * total counters. Now, it's possible to scale the 'regular' frames. */
1259    
1260          /* Scaling factor for 'regular' frames */          /* Scaling factor for 'regular' frames */
1261          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;  
         }  
1262    
1263          /* Do another pass with the new scaler */          /* Do another pass with the new scaler */
1264          for (i=0; i<rc->num_frames; i++) {          for (i=0; i<rc->num_frames; i++) {
# Line 1177  Line 1266 
1266    
1267                  /* Ignore frame with forced frame sizes */                  /* Ignore frame with forced frame sizes */
1268                  if (s->scaled_length == 0)                  if (s->scaled_length == 0)
1269                          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);
1270          }          }
1271    
1272          /* Job done */          /* Job done */
# Line 1192  Line 1281 
1281  scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)  scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)
1282  {  {
1283          int i;          int i;
1284          uint64_t ivop_boost_total;          int64_t ivop_boost_total;
1285    
1286          /* Reset the rate controller (per frame type) total byte counters */          /* Reset the rate controller (per frame type) total byte counters */
1287          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 1304 
1304    
1305                  /* Some more work is needed for I frames */                  /* Some more work is needed for I frames */
1306                  if (s->type == XVID_TYPE_IVOP) {                  if (s->type == XVID_TYPE_IVOP) {
                         int penalty_distance;  
1307                          int ivop_boost;                          int ivop_boost;
1308    
1309                          /* Accumulate bytes needed for keyframe boosting */                          /* Accumulate bytes needed for keyframe boosting */
1310                          ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;                          ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;
1311    
1312                          if (rc->KF_idx) {  #if 0 /* ToDo: decide how to apply kfthresholding */
1313                                  /* 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;  
                         }  
   
1314                          /* 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 */
1315                          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])
1316                                  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 1340 
1340    
1341          /* Compute the ratio described above          /* Compute the ratio described above
1342           *     taxed_total = sum(0, n, tax*scaled_length)           *     taxed_total = sum(0, n, tax*scaled_length)
1343           * <=> taxed_total = tax.sum(0, n, tax*scaled_length)           * <=> taxed_total = tax.sum(0, n, scaled_length)
1344           * <=> tax = taxed_total / original_total */           * <=> tax = taxed_total / original_total */
1345          rc->pb_iboost_tax_ratio =          rc->pb_iboost_tax_ratio =
1346                  (rc->pb_iboost_tax_ratio - ivop_boost_total) /                  (rc->pb_iboost_tax_ratio - ivop_boost_total) /
# Line 1278  Line 1357 
1357                  } else {                  } else {
1358                          rc->avg_length[i] = rc->tot_scaled_length[i];                          rc->avg_length[i] = rc->tot_scaled_length[i];
1359    
1360                          if (i == XVID_TYPE_IVOP) {                          if (i == (XVID_TYPE_IVOP-1)) {
1361                                  /* I Frames total has to be added the boost total */                                  /* I Frames total has to be added the boost total */
1362                                  rc->avg_length[i] += ivop_boost_total;                                  rc->avg_length[i] += ivop_boost_total;
1363                          } else {                          } else {
# Line 1355  Line 1434 
1434  }  }
1435    
1436  /*****************************************************************************  /*****************************************************************************
1437     * VBV compliancy check and scale
1438     * MPEG-4 standard specifies certain restrictions for bitrate/framesize in VBR
1439     * to enable playback on devices with limited readspeed and memory (and which
1440     * aren't...)
1441     *
1442     * DivX profiles have 2 criteria: VBV as in MPEG standard
1443     *                                a limit on peak bitrate for any 3 seconds
1444     *
1445     * But if VBV is fulfilled, peakrate is automatically fulfilled in any profile
1446     * define so far, so we check for it (for completeness) but correct only VBV
1447     *
1448     *****************************************************************************/
1449    
1450    #define VBV_COMPLIANT 0
1451    #define VBV_UNDERFLOW 1 /* video buffer runs empty */
1452    #define VBV_OVERFLOW 2  /* doesn't exist for VBR encoding */
1453    #define VBV_PEAKRATE 4  /* peak bitrate (within 3s) violated */
1454    
1455    static int
1456    check_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps)
1457    {
1458            /* We do all calculations in float, for higher accuracy,
1459             * and in bytes for convenience.
1460             *
1461             * typical values from DivX Home Theater profile:
1462             *  vbv_size= 384*1024 (384kB)
1463             *  vbv_initial= 288*1024 (75% fill)
1464             *  maxrate= 4000000 (4MBps)
1465             *  peakrate= 10000000 (10MBps)
1466             *
1467             *  PAL: offset3s = 75 (3 seconds of 25fps)
1468             *  NTSC: offset3s = 90 (3 seconds of 29.97fps) or 72 (3 seconds of 23.976fps)
1469             */
1470    
1471            const float vbv_size = (float)rc->param.vbv_size/8.f;
1472            float vbvfill = (float)rc->param.vbv_initial/8.f;
1473            float vbvmin;
1474    
1475            const float maxrate = (float)rc->param.vbv_maxrate;
1476            const float peakrate = (float)rc->param.vbv_peakrate;
1477            const float r0 = (int)(maxrate/fps+0.5)/8.f;
1478    
1479            int bytes3s = 0;
1480            int offset3s = (int)(3.f*fps+0.5);
1481            int i;
1482    
1483            /* 1Gbit should be enough to inuitialize the vbvmin
1484             *      an arbitrary high value */
1485            vbvmin = 1000*1000*1000;
1486    
1487            for (i=0; i<rc->num_frames; i++) {
1488                    /* DivX 3s peak bitrate check  */
1489                    bytes3s += rc->stats[i].scaled_length;
1490                    if (i>=offset3s)
1491                            bytes3s -= rc->stats[i-offset3s].scaled_length;
1492    
1493                    if (8.f*bytes3s > 3*peakrate)
1494                            return(VBV_PEAKRATE);
1495    
1496                    /* update vbv fill level */
1497                    vbvfill += r0 - rc->stats[i].scaled_length;
1498    
1499                    /* this check is _NOT_ an "overflow"! only reading from disk stops then */
1500                    if (vbvfill > vbv_size)
1501                            vbvfill = vbv_size;
1502    
1503                    /* but THIS would be an underflow. report it! */
1504                    if (vbvfill < 0)
1505                            return(VBV_UNDERFLOW);
1506    
1507                    /* Store the minimum buffer filling */
1508                    if (vbvfill < vbvmin)
1509                            vbvmin = vbvfill;
1510            }
1511    
1512            DPRINTF(XVID_DEBUG_RC, "[xvid rc] Minimum buffer fill: %f bytes\n", vbvmin);
1513    
1514            return(VBV_COMPLIANT);
1515    }
1516    
1517    
1518    static int
1519    scale_curve_for_vbv_compliancy(rc_2pass2_t * rc, const float fps)
1520    {
1521            /* correct any VBV violations. Peak bitrate violations disappears
1522             * by this automatically
1523             *
1524             * This implementation follows
1525             *
1526             * Westerink, Rajagopalan, Gonzales "Two-pass MPEG-2 variable-bitrate encoding"
1527             * IBM J. RES. DEVELOP. VOL 43, No. 4, July 1999, p.471--488
1528             *
1529             * Thanks, guys! This paper rocks!!! */
1530    
1531            /* For each scene of len N, we have to check up to N^2 possible buffer fills.
1532             * This works well with MPEG-2 where N==12 or so, but for MPEG-4 it's a
1533             * little slow...
1534             *
1535             * TODO: Better control on VBVfill between scenes */
1536    
1537            const float vbv_size = (float)rc->param.vbv_size/8.f;
1538            const float vbv_initial = (float)rc->param.vbv_initial/8.f;
1539    
1540            const float maxrate = 0.9*rc->param.vbv_maxrate;
1541            const float vbv_low = 0.10f*vbv_size;
1542            const float r0 = (int)(maxrate/fps+0.5)/8.f;
1543    
1544            int i,k,l,n,violation = 0;
1545            float *scenefactor;
1546            int *scenestart;
1547            int *scenelength;
1548    
1549            /* first step: determine how many "scenes" there are and store their
1550             * boundaries we could get all this from existing keyframe_positions,
1551             * somehow, but there we don't have a min_scenelength, and it's no big
1552             * deal to get it again. */
1553    
1554            const int min_scenelength = (int)(fps+0.5);
1555            int num_scenes = 0;
1556            int last_scene = -999;
1557            for (i=0; i<rc->num_frames; i++) {
1558                    if ((rc->stats[i].type == XVID_TYPE_IVOP) && (i-last_scene>min_scenelength)) {
1559                            last_scene = i;
1560                            num_scenes++;
1561                    }
1562            }
1563    
1564            scenefactor = (float*)malloc(num_scenes*sizeof(float));
1565            scenestart = (int*)malloc(num_scenes*sizeof(int));
1566            scenelength = (int*)malloc(num_scenes*sizeof(int));
1567    
1568            if ((!scenefactor) || (!scenestart) || (!scenelength) ) {
1569                    free(scenefactor);
1570                    free(scenestart);
1571                    free(scenelength);
1572                    /* remember: free(0) is valid and does exactly nothing. */
1573                    return(-1);
1574            }
1575    
1576            /* count again and safe the length/position */
1577    
1578            num_scenes = 0;
1579            last_scene = -999;
1580            for (i=0; i<rc->num_frames; i++) {
1581                    if ((rc->stats[i].type == XVID_TYPE_IVOP) && (i-last_scene>min_scenelength)) {
1582                            if (num_scenes>0) {
1583                                    scenelength[num_scenes-1]=i-last_scene;
1584                            }
1585                            scenestart[num_scenes]=i;
1586                            num_scenes++;
1587                            last_scene = i;
1588                    }
1589            }
1590            scenelength[num_scenes-1]=i-last_scene;
1591    
1592            /* second step: check for each scene, how much we can scale its frames up or
1593             * down such that the VBV restriction is just fulfilled */
1594    #define R(k,n) (((n)+1-(k))*r0)     /* how much enters the buffer between frame k and n */
1595            for (l=0; l<num_scenes;l++) {
1596                    const int start = scenestart[l];
1597                    const int length = scenelength[l];
1598                    twopass_stat_t * frames = &rc->stats[start];
1599    
1600                    float S0n,Skn;
1601                    float f,minf = 99999.f;
1602    
1603                    S0n=0.;
1604                    for (n=0;n<=length-1;n++) {
1605                            S0n += frames[n].scaled_length;
1606    
1607                            k = 0;
1608                            Skn = S0n;
1609                            f = (R(k,n-1) + (vbv_initial - vbv_low)) / Skn;
1610                            if (f < minf)
1611                                    minf = f;
1612    
1613                            for (k=1;k<=n;k++) {
1614                                    Skn -= frames[k].scaled_length;
1615    
1616                                    f = (R(k,n-1) + (vbv_size - vbv_low)) / Skn;
1617                                    if (f < minf)
1618                                            minf = f;
1619                            }
1620                    }
1621    
1622                    /* special case: at the end, fill buffer up to vbv_initial again
1623                     *
1624                     * TODO: Allow other values for buffer fill between scenes
1625                     * e.g. if n=N is smallest f-value, then check for better value */
1626    
1627                    n=length;
1628                    k=0;
1629                    Skn = S0n;
1630                    f = R(k,n-1)/Skn;
1631                    if (f < minf)
1632                            minf = f;
1633    
1634                    for (k=1;k<=n-1;k++) {
1635                            Skn -= frames[k].scaled_length;
1636    
1637                            f = (R(k,n-1) + (vbv_initial - vbv_low)) / Skn;
1638                            if (f < minf)
1639                                    minf = f;
1640                    }
1641    
1642                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] Scene %d (Frames %d-%d): VBVfactor %f\n",
1643                                    l, start, start+length-1 , minf);
1644    
1645                    scenefactor[l] = minf;
1646            }
1647    #undef R
1648    
1649            /* last step: now we know of any scene how much it can be scaled up or down
1650             * without violating VBV. Next, distribute bits from the evil scenes to the
1651             * good ones */
1652            do {
1653                    float S_red = 0.f;    /* how much to redistribute */
1654                    float S_elig = 0.f;   /* sum of bit for those scenes you can still swallow something*/
1655                    float f_red;
1656                    int l;
1657    
1658                    /* check how much is wrong */
1659                    for (l=0;l<num_scenes;l++) {
1660                            const int start = scenestart[l];
1661                            const int length = scenelength[l];
1662                            twopass_stat_t * frames = &rc->stats[start];
1663    
1664                            /* exactly 1 means "don't touch this anymore!" */
1665                            if (scenefactor[l] == 1.)
1666                                    continue;
1667    
1668                            /* within limits */
1669                            if (scenefactor[l] > 1.) {
1670                                    for (n= 0; n < length; n++)
1671                                            S_elig += frames[n].scaled_length;
1672                            } else {
1673                                    /* underflowing segment */
1674                                    for (n= 0; n < length; n++) {
1675                                            float newbytes = (float)frames[n].scaled_length * scenefactor[l];
1676                                            S_red += (float)frames[n].scaled_length - (float)newbytes;
1677                                            frames[n].scaled_length =(int)newbytes;
1678                                    }
1679                                    scenefactor[l] = 1.f;
1680                            }
1681                    }
1682    
1683                    /* no more underflows */
1684                    if (S_red < 1.f)
1685                            break;
1686    
1687                    if (S_elig < 1.f) {
1688                            DPRINTF(XVID_DEBUG_RC, "[xvid rc] Everything underflowing.\n");
1689                            free(scenefactor);
1690                            free(scenestart);
1691                            free(scenelength);
1692                            return(-2);
1693                    }
1694    
1695                    f_red = (1.f + S_red/S_elig);
1696    
1697                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] Moving %.0f kB to avoid buffer underflow, correction factor: %.5f\n",
1698                                    S_red/1024.f, f_red);
1699    
1700                    violation=0;
1701                    /* scale remaining scenes up to meet total size */
1702                    for (l=0; l<num_scenes; l++) {
1703                            const int start = scenestart[l];
1704                            const int length = scenelength[l];
1705                            twopass_stat_t * frames = &rc->stats[start];
1706    
1707                            if (scenefactor[l] == 1.)
1708                                    continue;
1709    
1710                            /* there shouldn't be any segments with factor<1 left, so all the rest is >1 */
1711                            for (n= 0; n < length; n++) {
1712                                    frames[n].scaled_length = (int)(frames[n].scaled_length * f_red + 0.5);
1713                            }
1714    
1715                            scenefactor[l] /= f_red;
1716                            if (scenefactor[l] < 1.f)
1717                                    violation=1;
1718                    }
1719    
1720            } while (violation);
1721    
1722            free(scenefactor);
1723            free(scenestart);
1724            free(scenelength);
1725            return(0);
1726    }
1727    
1728    
1729    /*****************************************************************************
1730   * Still more low level stuff (nothing to do with stats treatment)   * Still more low level stuff (nothing to do with stats treatment)
1731   ****************************************************************************/   ****************************************************************************/
1732    

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