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revision 1.1, Tue Mar 25 10:58:33 2003 UTC revision 1.1.2.29, Sun Dec 7 15:08:15 2003 UTC
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1    /******************************************************************************
2     *
3     *  XviD Bit Rate Controller Library
4     *  - VBR 2 pass bitrate controller implementation -
5     *
6     *  Copyright (C)      2002 Foxer <email?>
7     *                     2002 Dirk Knop <dknop@gwdg.de>
8     *                2002-2003 Edouard Gomez <ed.gomez@free.fr>
9     *                     2003 Pete Ross <pross@xvid.org>
10     *
11     *  This curve treatment algorithm is the one originally implemented by Foxer
12     *  and tuned by Dirk Knop for the XviD vfw frontend.
13     *
14     *  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
16     *  the Free Software Foundation; either version 2 of the License, or
17     *  (at your option) any later version.
18     *
19     *  This program is distributed in the hope that it will be useful,
20     *  but WITHOUT ANY WARRANTY; without even the implied warranty of
21     *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22     *  GNU General Public License for more details.
23     *
24     *  You should have received a copy of the GNU General Public License
25     *  along with this program; if not, write to the Free Software
26     *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
27     *
28     * $Id$
29     *
30     *****************************************************************************/
31    
32    #undef COMPENSATE_FORMULA
33    
34    #include <stdio.h>
35    #include <math.h>
36    #include <limits.h>
37    
38    #include "../xvid.h"
39    #include "../image/image.h"
40    
41    /*****************************************************************************
42     * Some constants
43     ****************************************************************************/
44    
45    #define DEFAULT_KEYFRAME_BOOST 0
46    #define DEFAULT_OVERFLOW_CONTROL_STRENGTH 10
47    #define DEFAULT_CURVE_COMPRESSION_HIGH 0
48    #define DEFAULT_CURVE_COMPRESSION_LOW 0
49    #define DEFAULT_MAX_OVERFLOW_IMPROVEMENT 60
50    #define DEFAULT_MAX_OVERFLOW_DEGRADATION 60
51    
52    /* Keyframe settings */
53    #define DEFAULT_KFREDUCTION 20
54    #define DEFAULT_KFTHRESHOLD 1
55    
56    /*****************************************************************************
57     * Structures
58     ****************************************************************************/
59    
60    /* Statistics */
61    typedef struct {
62            int type;               /* first pass type */
63            int quant;              /* first pass quant */
64            int quant2;             /* Second pass quant */
65            int blks[3];                    /* k,m,y blks */
66            int length;             /* first pass length */
67            int scaled_length;      /* scaled length */
68            int desired_length;     /* desired length; calculated during encoding */
69            int error;
70    
71            int zone_mode;   /* XVID_ZONE_xxx */
72            double weight;
73    } twopass_stat_t;
74    
75    /* Context struct */
76    typedef struct
77    {
78            xvid_plugin_2pass2_t param;
79    
80            /*----------------------------------
81             * constant statistical data
82             *--------------------------------*/
83    
84            /* Number of frames of the sequence */
85            int num_frames;
86    
87            /* Number of Intra frames of the sequence */
88            int num_keyframes;
89    
90            /* Target filesize to reach */
91            uint64_t target;
92    
93            /* Count of each frame types */
94            int count[3];
95    
96            /* Total length of each frame types (1st pass) */
97            uint64_t tot_length[3];
98    
99            /* Average length of each frame types (used first for 1st pass data and
100             * then for scaled averages */
101            double avg_length[3];
102    
103            /* Minimum frame length allowed for each frame type */
104            int min_length[3];
105    
106            /* Total bytes per frame type once the curve has been scaled
107             * NB: advanced parameters do not change this value. This field
108             *     represents the total scaled w/o any advanced settings */
109            uint64_t tot_scaled_length[3];
110    
111            /* Maximum observed frame size observed during the first pass, the RC
112             * will try tp force all frame sizes in the second pass to be under that
113             * limit */
114            int max_length;
115    
116            /*----------------------------------
117             * Zones statistical data
118             *
119             * ToDo: Fix zones, current
120             *       implementation is buggy
121             *--------------------------------*/
122    
123            /* Average weight of the zones */
124            double avg_weight;
125    
126            /* Total length used by XVID_ZONE_QUANT zones */
127            int64_t tot_quant;
128    
129            /*----------------------------------
130             * Advanced settings helper ratios
131             *--------------------------------*/
132    
133            /* This the ratio that has to be applied to all p/b frames in order
134             * to reserve/retrieve bits for/from keyframe boosting and consecutive
135             * keyframe penalty */
136            double pb_iboost_tax_ratio;
137    
138            /* This the ratio to apply to all b/p frames in order to respect the
139             * assymetric curve compression while respecting a target filesize
140             * NB: The assymetric delta gain has to be computed before this ratio
141             *     is applied, and then the delta is added to the scaled size */
142            double assymetric_tax_ratio;
143    
144            /*----------------------------------
145             * Data from the stats file kept
146             * into RAM for easy access
147             *--------------------------------*/
148    
149            /* Array of keyframe locations
150             * eg: rc->keyframe_locations[100] returns the frame number of the 100th
151             *     keyframe */
152            int *keyframe_locations;
153    
154            /* Index of the last keyframe used in the keyframe_location */
155            int KF_idx;
156    
157            /* Array of all 1st pass data file -- see the twopass_stat_t structure
158             * definition for more details */
159            twopass_stat_t * stats;
160    
161            /*----------------------------------
162             * Histerysis helpers
163             *--------------------------------*/
164    
165            /* This field holds the int2float conversion errors of each quant per
166             * frame type, this allow the RC to keep track of rouding error and thus
167             * increase or decrease the chosen quant according to this residue */
168            double quant_error[3][32];
169    
170            /* This fields stores the count of each quant usage per frame type
171             * No real role but for debugging */
172            int quant_count[3][32];
173    
174            /* Last valid quantizer used per frame type, it allows quantizer
175             * increament/decreament limitation in order to avoid big image quality
176             * "jumps" */
177            int last_quant[3];
178    
179            /*----------------------------------
180             * Overflow control
181             *--------------------------------*/
182    
183            /* Current overflow that has to be distributed to p/b frames */
184            double overflow;
185    
186            /* Total overflow for keyframes -- not distributed directly */
187            double KFoverflow;
188    
189            /* Amount of keyframe overflow to introduce to the global p/b frame
190             * overflow counter at each encoded frame */
191            double KFoverflow_partial;
192    
193            /* Unknown ???
194             * ToDo: description */
195            double fq_error;
196    
197            /*----------------------------------
198             * Debug
199             *--------------------------------*/
200            double desired_total;
201            double real_total;
202    } rc_2pass2_t;
203    
204    
205    /*****************************************************************************
206     * Sub plugin functions prototypes
207     ****************************************************************************/
208    
209    static int rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t ** handle);
210    static int rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data);
211    static int rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data);
212    static int rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy);
213    
214    /*****************************************************************************
215     * Plugin definition
216     ****************************************************************************/
217    
218    int
219    xvid_plugin_2pass2(void * handle, int opt, void * param1, void * param2)
220    {
221            switch(opt) {
222            case XVID_PLG_INFO :
223            case XVID_PLG_FRAME :
224                    return 0;
225    
226            case XVID_PLG_CREATE :
227                    return rc_2pass2_create((xvid_plg_create_t*)param1, param2);
228    
229            case XVID_PLG_DESTROY :
230                    return rc_2pass2_destroy((rc_2pass2_t*)handle, (xvid_plg_destroy_t*)param1);
231    
232            case XVID_PLG_BEFORE :
233                    return rc_2pass2_before((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
234    
235            case XVID_PLG_AFTER :
236                    return rc_2pass2_after((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
237            }
238    
239            return XVID_ERR_FAIL;
240    }
241    
242    /*****************************************************************************
243     * Sub plugin functions definitions
244     ****************************************************************************/
245    
246    /* First a few local helping function prototypes */
247    static  int statsfile_count_frames(rc_2pass2_t * rc, char * filename);
248    static  int statsfile_load(rc_2pass2_t *rc, char * filename);
249    static void zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create);
250    static void first_pass_stats_prepare_data(rc_2pass2_t * rc);
251    static void first_pass_scale_curve_internal(rc_2pass2_t *rc);
252    static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);
253    #if 0
254    static void stats_print(rc_2pass2_t * rc);
255    #endif
256    
257    /*----------------------------------------------------------------------------
258     *--------------------------------------------------------------------------*/
259    
260    static int
261    rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t **handle)
262    {
263            xvid_plugin_2pass2_t * param = (xvid_plugin_2pass2_t *)create->param;
264            rc_2pass2_t * rc;
265            int i;
266    
267            rc = malloc(sizeof(rc_2pass2_t));
268            if (rc == NULL)
269                    return XVID_ERR_MEMORY;
270    
271            rc->param = *param;
272    
273            /* Initialize all defaults */
274    #define _INIT(a, b) if((a) <= 0) (a) = (b)
275            /* Let's set our defaults if needed */
276            _INIT(rc->param.keyframe_boost, DEFAULT_KEYFRAME_BOOST);
277            _INIT(rc->param.overflow_control_strength, DEFAULT_OVERFLOW_CONTROL_STRENGTH);
278            _INIT(rc->param.curve_compression_high, DEFAULT_CURVE_COMPRESSION_HIGH);
279            _INIT(rc->param.curve_compression_low, DEFAULT_CURVE_COMPRESSION_LOW);
280            _INIT(rc->param.max_overflow_improvement, DEFAULT_MAX_OVERFLOW_IMPROVEMENT);
281            _INIT(rc->param.max_overflow_degradation,  DEFAULT_MAX_OVERFLOW_DEGRADATION);
282    
283            /* Keyframe settings */
284            _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);
285            _INIT(rc->param.kfthreshold, DEFAULT_KFTHRESHOLD);
286    #undef _INIT
287    
288            /* Initialize some stuff to zero */
289            for(i=0; i<3; i++) {
290                    int j;
291                    for (j=0; j<32; j++) {
292                            rc->quant_error[i][j] = 0;
293                            rc->quant_count[i][j] = 0;
294                    }
295            }
296    
297            for (i=0; i<3; i++) rc->last_quant[i] = 0;
298    
299            rc->fq_error = 0;
300    
301            /* Count frames (and intra frames) in the stats file, store the result into
302             * the rc structure */
303            if (statsfile_count_frames(rc, param->filename) == -1) {
304                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
305                    free(rc);
306                    return(XVID_ERR_FAIL);
307            }
308    
309            /* Allocate the stats' memory */
310            if ((rc->stats = malloc(rc->num_frames * sizeof(twopass_stat_t))) == NULL) {
311                    free(rc);
312                    return(XVID_ERR_MEMORY);
313            }
314    
315            /* Allocate keyframes location's memory
316             * PS: see comment in pre_process0 for the +1 location requirement */
317            rc->keyframe_locations = malloc((rc->num_keyframes + 1) * sizeof(int));
318            if (rc->keyframe_locations == NULL) {
319                    free(rc->stats);
320                    free(rc);
321                    return(XVID_ERR_MEMORY);
322            }
323    
324            /* Load the first pass stats */
325            if (statsfile_load(rc, param->filename) == -1) {
326                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
327                    free(rc->keyframe_locations);
328                    free(rc->stats);
329                    free(rc);
330                    return XVID_ERR_FAIL;
331            }
332    
333            /* Compute the target filesize */
334            if (rc->param.bitrate<0) {
335                    /* if negative, bitrate equals the target (in kbytes) */
336                    rc->target = ((uint64_t)(-rc->param.bitrate)) * 1024;
337            } else if (rc->num_frames  < create->fbase/create->fincr) {
338                    /* Source sequence is less than 1s long, we do as if it was 1s long */
339                    rc->target = rc->param.bitrate / 8;
340            } else {
341                    /* Target filesize = bitrate/8 * numframes / framerate */
342                    rc->target =
343                            ((uint64_t)rc->param.bitrate * (uint64_t)rc->num_frames * \
344                             (uint64_t)create->fincr) / \
345                            ((uint64_t)create->fbase * 8);
346            }
347    
348            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Frame rate: %d/%d (%ffps)\n",
349                            create->fbase, create->fincr,
350                            (double)create->fbase/(double)create->fincr);
351            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Number of frames: %d\n", rc->num_frames);
352            if(rc->param.bitrate>=0)
353                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target bitrate: %ld\n", rc->param.bitrate);
354            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target filesize: %lld\n", rc->target);
355    
356            /* Compensate the average frame overhead caused by the container */
357            rc->target -= rc->num_frames*rc->param.container_frame_overhead;
358            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Container Frame overhead: %d\n", rc->param.container_frame_overhead);
359            if(rc->param.container_frame_overhead)
360                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- New target filesize after container compensation: %lld\n", rc->target);
361    
362            /* Gathers some information about first pass stats:
363             *  - finds the minimum frame length for each frame type during 1st pass.
364             *     rc->min_size[]
365             *  - determines the maximum frame length observed (no frame type distinction).
366             *     rc->max_size
367             *  - count how many times each frame type has been used.
368             *     rc->count[]
369             *  - total bytes used per frame type
370             *     rc->total[]
371             *  - store keyframe location
372             *     rc->keyframe_locations[]
373             */
374            first_pass_stats_prepare_data(rc);
375    
376            /* When bitrate is not given it means it has been scaled by an external
377             * application */
378            if (rc->param.bitrate) {
379                    /* Apply zone settings */
380                    zone_process(rc, create);
381                    /* Perform internal curve scaling */
382                    first_pass_scale_curve_internal(rc);
383            } else {
384                    /* External scaling -- zones are ignored */
385                    for (i=0;i<rc->num_frames;i++) {
386                            rc->stats[i].zone_mode = XVID_ZONE_WEIGHT;
387                            rc->stats[i].weight = 1.0;
388                    }
389                    rc->avg_weight = 1.0;
390                    rc->tot_quant = 0;
391            }
392    
393            /* Apply advanced curve options, and compute some parameters in order to
394             * shape the curve in the BEFORE/AFTER pair of functions */
395            scaled_curve_apply_advanced_parameters(rc);
396    
397            *handle = rc;
398            return(0);
399    }
400    
401    /*----------------------------------------------------------------------------
402     *--------------------------------------------------------------------------*/
403    
404    static int
405    rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy)
406    {
407            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- target_total:%lld desired_total:%.2f (%.2f%%) actual_total:%.2f (%.2f%%)\n",
408                            rc->target,
409                            rc->desired_total,
410                            100*rc->desired_total/(double)rc->target,
411                            rc->real_total,
412                            100*rc->real_total/(double)rc->target);
413    
414            free(rc->keyframe_locations);
415            free(rc->stats);
416            free(rc);
417            return(0);
418    }
419    
420    /*----------------------------------------------------------------------------
421     *--------------------------------------------------------------------------*/
422    
423    static int
424    rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data)
425    {
426            twopass_stat_t * s = &rc->stats[data->frame_num];
427            double dbytes;
428            double scaled_quant;
429            double overflow;
430            int capped_to_max_framesize = 0;
431    
432            /* This function is quite long but easy to understand. In order to simplify
433             * the code path (a bit), we treat 3 cases that can return immediatly. */
434    
435            /* First case: Another plugin has already set a quantizer */
436            if (data->quant > 0)
437                    return(0);
438    
439            /* Second case: We are in a Quant zone */
440            if (s->zone_mode == XVID_ZONE_QUANT) {
441                    rc->fq_error += s->weight;
442                    data->quant = (int)rc->fq_error;
443                    rc->fq_error -= data->quant;
444    
445                    s->desired_length = s->length;
446    
447                    return(0);
448            }
449    
450            /* Third case: insufficent stats data */
451            if (data->frame_num >= rc->num_frames)
452                    return(0);
453    
454            /*************************************************************************/
455            /*************************************************************************/
456            /*************************************************************************/
457    
458            /*-------------------------------------------------------------------------
459             * Frame bit allocation first part
460             *
461             * First steps apply user settings, just like it is done in the theoritical
462             * scaled_curve_apply_advanced_parameters
463             *-----------------------------------------------------------------------*/
464    
465            /* Set desired to what we are wanting to obtain for this frame */
466            dbytes = (double)s->scaled_length;
467    
468            /* IFrame user settings*/
469            if (s->type == XVID_TYPE_IVOP) {
470                    /* Keyframe boosting -- All keyframes benefit from it */
471                    dbytes += dbytes*rc->param.keyframe_boost / 100;
472    
473    #if 0 /* ToDo: decide how to apply kfthresholding */
474    #endif
475            } else {
476    
477                    /* P/S/B frames must reserve some bits for iframe boosting */
478                    dbytes *= rc->pb_iboost_tax_ratio;
479    
480                    /* Apply assymetric curve compression */
481                    if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
482                            double assymetric_delta;
483    
484                            /* Compute the assymetric delta, this is computed before applying
485                             * the tax, as done in the pre_process function */
486                            if (dbytes > rc->avg_length[s->type-1])
487                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_high / 100.0;
488                            else
489                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_low  / 100.0;
490    
491                            /* Now we must apply the assymetric tax, else our curve compression
492                             * would not give a theoritical target size equal to what it is
493                             * expected */
494                            dbytes *= rc->assymetric_tax_ratio;
495    
496                            /* Now we can add the assymetric delta */
497                            dbytes += assymetric_delta;
498                    }
499            }
500    
501            /* That is what we would like to have -- Don't put that chunk after
502             * overflow control, otherwise, overflow is counted twice and you obtain
503             * half sized bitrate sequences */
504            s->desired_length  = (int)dbytes;
505            rc->desired_total += dbytes;
506    
507            /*------------------------------------------------------------------------
508             * Frame bit allocation: overflow control part.
509             *
510             * Unlike the theoritical scaled_curve_apply_advanced_parameters, here
511             * it's real encoding and we need to make sure we don't go so far from
512             * what is our ideal scaled curve.
513             *-----------------------------------------------------------------------*/
514    
515            /* Compute the overflow we should compensate */
516            if (s->type != XVID_TYPE_IVOP) {
517                    double frametype_factor;
518                    double framesize_factor;
519    
520                    /* Take only the desired part of overflow */
521                    overflow = rc->overflow;
522    
523                    /* Factor that will take care to decrease the overflow applied
524                     * according to the importance of this frame type in term of
525                     * overall size */
526                    frametype_factor  = rc->count[XVID_TYPE_IVOP-1]*rc->avg_length[XVID_TYPE_IVOP-1];
527                    frametype_factor += rc->count[XVID_TYPE_PVOP-1]*rc->avg_length[XVID_TYPE_PVOP-1];
528                    frametype_factor += rc->count[XVID_TYPE_BVOP-1]*rc->avg_length[XVID_TYPE_BVOP-1];
529                    frametype_factor /= rc->count[s->type-1]*rc->avg_length[s->type-1];
530                    frametype_factor  = 1/frametype_factor;
531    
532                    /* Factor that will take care not to compensate too much for this frame
533                     * size */
534                    framesize_factor  = dbytes;
535                    framesize_factor /= rc->avg_length[s->type-1];
536    
537                    /* Treat only the overflow part concerned by this frame type and size */
538                    overflow *= frametype_factor;
539    #if 0
540                    /* Leave this one alone, as it impacts badly on quality */
541                    overflow *= framesize_factor;
542    #endif
543    
544                    /* Apply the overflow strength imposed by the user */
545                    overflow *= (rc->param.overflow_control_strength/100.0f);
546            } else {
547                    /* no overflow applied in IFrames because:
548                     *  - their role is important as they're references for P/BFrames.
549                     *  - there aren't much in typical sequences, so if an IFrame overflows too
550                     *    much, this overflow may impact the next IFrame too much and generate
551                     *    a sequence of poor quality frames */
552                    overflow = 0;
553            }
554    
555            /* Make sure we are not trying to compensate more overflow than we even have */
556            if (fabs(overflow) > fabs(rc->overflow))
557                    overflow = rc->overflow;
558    
559            /* Make sure the overflow doesn't make the frame size to get out of the range
560             * [-max_degradation..+max_improvment] */
561            if (overflow > dbytes*rc->param.max_overflow_improvement / 100) {
562                    if(overflow <= dbytes)
563                            dbytes += dbytes * rc->param.max_overflow_improvement / 100;
564                    else
565                            dbytes += overflow * rc->param.max_overflow_improvement / 100;
566            } else if (overflow < - dbytes * rc->param.max_overflow_degradation / 100) {
567                    dbytes -= dbytes * rc->param.max_overflow_degradation / 100;
568            } else {
569                    dbytes += overflow;
570            }
571    
572            /*-------------------------------------------------------------------------
573             * Frame bit allocation last part:
574             *
575             * Cap frame length so we don't reach neither bigger frame sizes than first
576             * pass nor smaller than the allowed minimum.
577             *-----------------------------------------------------------------------*/
578    
579            if (dbytes > s->length) {
580                    dbytes = s->length;
581            } else if (dbytes < rc->min_length[s->type-1]) {
582                    dbytes = rc->min_length[s->type-1];
583            } else if (dbytes > rc->max_length) {
584                    /* ToDo: this condition is always wrong as max_length == maximum frame
585                     * length of first pass, so the first condition already caps the frame
586                     * size... */
587                    capped_to_max_framesize = 1;
588                    dbytes = rc->max_length;
589                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- frame:%d Capped to maximum frame size\n",
590                                    data->frame_num);
591            }
592    
593            /*------------------------------------------------------------------------
594             * Desired frame length <-> quantizer mapping
595             *-----------------------------------------------------------------------*/
596    
597            /* For bframes we must retrieve the original quant used (sent to xvidcore)
598             * as core applies the bquant formula before writing the stat log entry */
599            if(s->type == XVID_TYPE_BVOP) {
600    
601                    twopass_stat_t *b_ref = s;
602    
603                    /* Find the reference frame */
604                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
605                            b_ref--;
606    
607                    /* Compute the original quant */
608                    s->quant  = 2*(100*s->quant - data->bquant_offset);
609                    s->quant += data->bquant_ratio - 1; /* to avoid rouding issues */
610                    s->quant  = s->quant/data->bquant_ratio - b_ref->quant;
611            }
612    
613            /* Don't laugh at this very 'simple' quant<->filesize relationship, it
614             * proves to be acurate enough for our algorithm */
615            scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;
616    
617    #ifdef COMPENSATE_FORMULA
618            /* We know xvidcore will apply the bframe formula again, so we compensate
619             * it right now to make sure we would not apply it twice */
620            if(s->type == XVID_TYPE_BVOP) {
621    
622                    twopass_stat_t *b_ref = s;
623    
624                    /* Find the reference frame */
625                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
626                            b_ref--;
627    
628                    /* Compute the quant it would be if the core did not apply the bframe
629                     * formula */
630                    scaled_quant  = 100*scaled_quant - data->bquant_offset;
631                    scaled_quant += data->bquant_ratio - 1; /* to avoid rouding issues */
632                    scaled_quant /= data->bquant_ratio;
633            }
634    #endif
635    
636            /* Quantizer has been scaled using floating point operations/results, we
637             * must cast it to integer */
638            data->quant = (int)scaled_quant;
639    
640            /* Let's clip the computed quantizer, if needed */
641            if (data->quant < 1) {
642                    data->quant = 1;
643            } else if (data->quant > 31) {
644                    data->quant = 31;
645            } else {
646    
647                    /* The frame quantizer has not been clipped, this appears to be a good
648                     * computed quantizer, do not loose quantizer decimal part that we
649                     * accumulate for later reuse when its sum represents a complete
650                     * unit. */
651                    rc->quant_error[s->type-1][data->quant] += scaled_quant - (double)data->quant;
652    
653                    if (rc->quant_error[s->type-1][data->quant] >= 1.0) {
654                            rc->quant_error[s->type-1][data->quant] -= 1.0;
655                            data->quant++;
656                    } else if (rc->quant_error[s->type-1][data->quant] <= -1.0) {
657                            rc->quant_error[s->type-1][data->quant] += 1.0;
658                            data->quant--;
659                    }
660            }
661    
662            /* Now we have a computed quant that is in the right quante range, with a
663             * possible +1 correction due to cumulated error. We can now safely clip
664             * the quantizer again with user's quant ranges. "Safely" means the Rate
665             * Control could learn more about this quantizer, this knowledge is useful
666             * for future frames even if it this quantizer won't be really used atm,
667             * that's why we don't perform this clipping earlier. */
668            if (data->quant < data->min_quant[s->type-1]) {
669                    data->quant = data->min_quant[s->type-1];
670            } else if (data->quant > data->max_quant[s->type-1]) {
671                    data->quant = data->max_quant[s->type-1];
672            }
673    
674            /* To avoid big quality jumps from frame to frame, we apply a "security"
675             * rule that makes |last_quant - new_quant| <= 2. This rule only applies
676             * to predicted frames (P and B) */
677            if (s->type != XVID_TYPE_IVOP && rc->last_quant[s->type-1] && capped_to_max_framesize == 0) {
678    
679                    if (data->quant > rc->last_quant[s->type-1] + 2) {
680                            data->quant = rc->last_quant[s->type-1] + 2;
681                            DPRINTF(XVID_DEBUG_RC,
682                                            "[xvid rc] -- frame %d p/b-frame quantizer prevented from rising too steeply\n",
683                                            data->frame_num);
684                    }
685                    if (data->quant < rc->last_quant[s->type-1] - 2) {
686                            data->quant = rc->last_quant[s->type-1] - 2;
687                            DPRINTF(XVID_DEBUG_RC,
688                                            "[xvid rc] -- frame:%d p/b-frame quantizer prevented from falling too steeply\n",
689                                            data->frame_num);
690                    }
691            }
692    
693            /* We don't want to pollute the RC histerisis when our computed quant has
694             * been computed from a capped frame size */
695            if (capped_to_max_framesize == 0)
696                    rc->last_quant[s->type-1] = data->quant;
697    
698            /* Don't forget to force 1st pass frame type ;-) */
699            data->type = s->type;
700    
701            /* Store the quantizer into the statistics -- Used to compensate the double
702             * formula symptom */
703            s->quant2 = data->quant;
704    
705            return 0;
706    }
707    
708    /*----------------------------------------------------------------------------
709     *--------------------------------------------------------------------------*/
710    
711    static int
712    rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data)
713    {
714            const char frame_type[4] = { 'i', 'p', 'b', 's'};
715            twopass_stat_t * s = &rc->stats[data->frame_num];
716    
717            /* Insufficent stats data */
718            if (data->frame_num >= rc->num_frames)
719                    return 0;
720    
721            /* Update the quantizer counter */
722            rc->quant_count[s->type-1][data->quant]++;
723    
724            /* Update the frame type overflow */
725            if (data->type == XVID_TYPE_IVOP) {
726                    int kfdiff = 0;
727    
728                    if(rc->KF_idx != rc->num_frames -1) {
729                            kfdiff  = rc->keyframe_locations[rc->KF_idx+1];
730                            kfdiff -= rc->keyframe_locations[rc->KF_idx];
731                    }
732    
733                    /* Flush Keyframe overflow accumulator */
734                    rc->overflow += rc->KFoverflow;
735    
736                    /* Store the frame overflow to the keyframe accumulator */
737                    rc->KFoverflow = s->desired_length - data->length;
738    
739                    if (kfdiff > 1) {
740                            /* Non-consecutive keyframes case:
741                             * We can then divide this total keyframe overflow into equal parts
742                             * that we will distribute into regular overflow at each frame
743                             * between the sequence bounded by two IFrames */
744                            rc->KFoverflow_partial = rc->KFoverflow / (kfdiff - 1);
745                    } else {
746                            /* Consecutive keyframes case:
747                             * Flush immediatly the keyframe overflow and reset keyframe
748                             * overflow */
749                            rc->overflow += rc->KFoverflow;
750                            rc->KFoverflow = 0;
751                            rc->KFoverflow_partial = 0;
752                    }
753                    rc->KF_idx++;
754            } else {
755                    /* Accumulate the frame overflow */
756                    rc->overflow += s->desired_length - data->length;
757    
758                    /* Distribute part of the keyframe overflow */
759                    rc->overflow += rc->KFoverflow_partial;
760    
761                    /* Don't forget to substract that same amount from the total keyframe
762                     * overflow */
763                    rc->KFoverflow -= rc->KFoverflow_partial;
764            }
765    
766            rc->overflow += s->error = s->desired_length - data->length;
767            rc->real_total += data->length;
768    
769            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",
770                            data->frame_num,
771                            frame_type[data->type-1],
772                            data->quant,
773                            s->length,
774                            s->scaled_length,
775                            s->desired_length,
776                            s->desired_length - s->error,
777                            -s->error,
778                            rc->overflow);
779    
780            return(0);
781    }
782    
783    /*****************************************************************************
784     * Helper functions definition
785     ****************************************************************************/
786    
787    /* Default buffer size for reading lines */
788    #define BUF_SZ   1024
789    
790    /* Helper functions for reading/parsing the stats file */
791    static char *skipspaces(char *string);
792    static int iscomment(char *string);
793    static char *readline(FILE *f);
794    
795    /* This function counts the number of frame entries in the stats file
796     * It also counts the number of I Frames */
797    static int
798    statsfile_count_frames(rc_2pass2_t * rc, char * filename)
799    {
800            FILE * f;
801            char *line;
802            int lines;
803    
804            rc->num_frames = 0;
805            rc->num_keyframes = 0;
806    
807            if ((f = fopen(filename, "rb")) == NULL)
808                    return(-1);
809    
810            lines = 0;
811            while ((line = readline(f)) != NULL) {
812    
813                    char *ptr;
814                    char type;
815                    int fields;
816    
817                    lines++;
818    
819                    /* We skip spaces */
820                    ptr = skipspaces(line);
821    
822                    /* Skip coment lines or empty lines */
823                    if(iscomment(ptr) || *ptr == '\0') {
824                            free(line);
825                            continue;
826                    }
827    
828                    /* Read the stat line from buffer */
829                    fields = sscanf(ptr, "%c", &type);
830    
831                    /* Valid stats files have at least 6 fields */
832                    if (fields == 1) {
833                            switch(type) {
834                            case 'i':
835                            case 'I':
836                                    rc->num_keyframes++;
837                            case 'p':
838                            case 'P':
839                            case 'b':
840                            case 'B':
841                            case 's':
842                            case 'S':
843                                    rc->num_frames++;
844                                    break;
845                            default:
846                                    DPRINTF(XVID_DEBUG_RC,
847                                                    "[xvid rc] -- WARNING: L%d unknown frame type used (%c).\n",
848                                                    lines, type);
849                            }
850                    } else {
851                                    DPRINTF(XVID_DEBUG_RC,
852                                                    "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",
853                                                    lines, 6-fields);
854                    }
855    
856                    /* Free the line buffer */
857                    free(line);
858            }
859    
860            /* We are done with the file */
861            fclose(f);
862    
863            return(0);
864    }
865    
866    /* open stats file(s) and read into rc->stats array */
867    static int
868    statsfile_load(rc_2pass2_t *rc, char * filename)
869    {
870            FILE * f;
871            int processed_entries;
872    
873            /* Opens the file */
874            if ((f = fopen(filename, "rb"))==NULL)
875                    return(-1);
876    
877            processed_entries = 0;
878            while(processed_entries < rc->num_frames) {
879                    char type;
880                    int fields;
881                    twopass_stat_t * s = &rc->stats[processed_entries];
882                    char *line, *ptr;
883    
884                    /* Read the line from the file */
885                    if((line = readline(f)) == NULL)
886                            break;
887    
888                    /* We skip spaces */
889                    ptr = skipspaces(line);
890    
891                    /* Skip comment lines or empty lines */
892                    if(iscomment(ptr) || *ptr == '\0') {
893                            free(line);
894                            continue;
895                    }
896    
897                    /* Reset this field that is optional */
898                    s->scaled_length = 0;
899    
900                    /* Convert the fields */
901                    fields = sscanf(ptr,
902                                                    "%c %d %d %d %d %d %d\n",
903                                                    &type,
904                                                    &s->quant,
905                                                    &s->blks[0], &s->blks[1], &s->blks[2],
906                                                    &s->length,
907                                                    &s->scaled_length);
908    
909                    /* Free line buffer, we don't need it anymore */
910                    free(line);
911    
912                    /* Fail silently, this has probably been warned in
913                     * statsfile_count_frames */
914                    if(fields != 6 && fields != 7)
915                            continue;
916    
917                    /* Convert frame type */
918                    switch(type) {
919                    case 'i':
920                    case 'I':
921                            s->type = XVID_TYPE_IVOP;
922                            break;
923                    case 'p':
924                    case 'P':
925                    case 's':
926                    case 'S':
927                            s->type = XVID_TYPE_PVOP;
928                            break;
929                    case 'b':
930                    case 'B':
931                            s->type = XVID_TYPE_BVOP;
932                            break;
933                    default:
934                            /* Same as before, fail silently */
935                            continue;
936                    }
937    
938                    /* Ok it seems it's been processed correctly */
939                    processed_entries++;
940            }
941    
942            /* Close the file */
943            fclose(f);
944    
945            return(0);
946    }
947    
948    /* pre-process the statistics data
949     * - for each type, count, tot_length, min_length, max_length
950     * - set keyframes_locations */
951    static void
952    first_pass_stats_prepare_data(rc_2pass2_t * rc)
953    {
954            int i,j;
955    
956            /* *rc fields initialization
957             * NB: INT_MAX and INT_MIN are used in order to be immediately replaced
958             *     with real values of the 1pass */
959            for (i=0; i<3; i++) {
960                    rc->count[i]=0;
961                    rc->tot_length[i] = 0;
962                    rc->min_length[i] = INT_MAX;
963            }
964    
965            rc->max_length = INT_MIN;
966    
967            /* Loop through all frames and find/compute all the stuff this function
968             * is supposed to do */
969            for (i=j=0; i<rc->num_frames; i++) {
970                    twopass_stat_t * s = &rc->stats[i];
971    
972                    rc->count[s->type-1]++;
973                    rc->tot_length[s->type-1] += s->length;
974    
975                    if (s->length < rc->min_length[s->type-1]) {
976                            rc->min_length[s->type-1] = s->length;
977                    }
978    
979                    if (s->length > rc->max_length) {
980                            rc->max_length = s->length;
981                    }
982    
983                    if (s->type == XVID_TYPE_IVOP) {
984                            rc->keyframe_locations[j] = i;
985                            j++;
986                    }
987            }
988    
989            /* NB:
990             * The "per sequence" overflow system considers a natural sequence to be
991             * formed by all frames between two iframes, so if we want to make sure
992             * the system does not go nuts during last sequence, we force the last
993             * frame to appear in the keyframe locations array. */
994            rc->keyframe_locations[j] = i;
995    
996            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass IFrame length: %d\n", rc->min_length[0]);
997            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass PFrame length: %d\n", rc->min_length[1]);
998            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass BFrame length: %d\n", rc->min_length[2]);
999    }
1000    
1001    /* calculate zone weight "center" */
1002    static void
1003    zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create)
1004    {
1005            int i,j;
1006            int n = 0;
1007    
1008            rc->avg_weight = 0.0;
1009            rc->tot_quant = 0;
1010    
1011    
1012            if (create->num_zones == 0) {
1013                    for (j = 0; j < rc->num_frames; j++) {
1014                            rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1015                            rc->stats[j].weight = 1.0;
1016                    }
1017                    rc->avg_weight += rc->num_frames * 1.0;
1018                    n += rc->num_frames;
1019            }
1020    
1021    
1022            for(i=0; i < create->num_zones; i++) {
1023    
1024                    int next = (i+1<create->num_zones) ? create->zones[i+1].frame : rc->num_frames;
1025    
1026                    if (i==0 && create->zones[i].frame > 0) {
1027                            for (j = 0; j < create->zones[i].frame && j < rc->num_frames; j++) {
1028                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1029                                    rc->stats[j].weight = 1.0;
1030                            }
1031                            rc->avg_weight += create->zones[i].frame * 1.0;
1032                            n += create->zones[i].frame;
1033                    }
1034    
1035                    if (create->zones[i].mode == XVID_ZONE_WEIGHT) {
1036                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1037                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1038                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1039                            }
1040                            next -= create->zones[i].frame;
1041                            rc->avg_weight += (double)(next * create->zones[i].increment) / (double)create->zones[i].base;
1042                            n += next;
1043                    }else{  /* XVID_ZONE_QUANT */
1044                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1045                                    rc->stats[j].zone_mode = XVID_ZONE_QUANT;
1046                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1047                                    rc->tot_quant += rc->stats[j].length;
1048                            }
1049                    }
1050            }
1051            rc->avg_weight = n>0 ? rc->avg_weight/n : 1.0;
1052    
1053            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- center_weight:%f (for %d frames)  fixed_bytes:%d\n", rc->avg_weight, n, rc->tot_quant);
1054    }
1055    
1056    
1057    /* scale the curve */
1058    static void
1059    first_pass_scale_curve_internal(rc_2pass2_t *rc)
1060    {
1061            int64_t target;
1062            int64_t pass1_length;
1063            double scaler;
1064            int i, num_MBs;
1065    
1066            /* We remove the bytes used by the fixed quantizer zones
1067             * ToDo: this approach is flawed, the same amount of bytes is removed from
1068             *       target and first pass data, this has no sense, zone_process should
1069             *       give us two results one for unscaled data (1pass) and the other
1070             *       one for scaled data and we should then write:
1071             *       target = rc->target - rc->tot_quant_scaled;
1072             *       pass1_length = rc->i+p+b - rc->tot_quant_firstpass */
1073            target = rc->target - rc->tot_quant;
1074    
1075            /* Do the same for the first pass data */
1076            pass1_length  = rc->tot_length[XVID_TYPE_IVOP-1];
1077            pass1_length += rc->tot_length[XVID_TYPE_PVOP-1];
1078            pass1_length += rc->tot_length[XVID_TYPE_BVOP-1];
1079            pass1_length -= rc->tot_quant;
1080    
1081            /* Let's compute a linear scaler in order to perform curve scaling */
1082            scaler = (double)target / (double)pass1_length;
1083    
1084            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1085                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected before correction\n");
1086                    scaler = 1.0;
1087            }
1088    
1089            /* Compute min frame lengths (for each frame type) according to the number
1090             * of MBs. We sum all block type counters of frame 0, this gives us the
1091             * number of MBs.
1092             *
1093             * We compare these hardcoded values with observed values in first pass
1094             * (determined in pre_process0).Then we keep the real minimum. */
1095    
1096            /* Number of MBs */
1097            num_MBs  = rc->stats[0].blks[0];
1098            num_MBs += rc->stats[0].blks[1];
1099            num_MBs += rc->stats[0].blks[2];
1100    
1101            /* Minimum for I frames */
1102            if(rc->min_length[XVID_TYPE_IVOP-1] > ((num_MBs*22) + 240) / 8)
1103                    rc->min_length[XVID_TYPE_IVOP-1] = ((num_MBs*22) + 240) / 8;
1104    
1105            /* Minimum for P/S frames */
1106            if(rc->min_length[XVID_TYPE_PVOP-1] > ((num_MBs) + 88)  / 8)
1107                    rc->min_length[XVID_TYPE_PVOP-1] = ((num_MBs) + 88)  / 8;
1108    
1109            /* Minimum for B frames */
1110            if(rc->min_length[XVID_TYPE_BVOP-1] > 8)
1111                    rc->min_length[XVID_TYPE_BVOP-1] = 8;
1112    
1113            /* Perform an initial scale pass.
1114             *
1115             * If a frame size is scaled underneath our hardcoded minimums, then we
1116             * force the frame size to the minimum, and deduct the original & scaled
1117             * frame length from the original and target total lengths */
1118            for (i=0; i<rc->num_frames; i++) {
1119                    twopass_stat_t * s = &rc->stats[i];
1120                    int len;
1121    
1122                    /* No need to scale frame length for which a specific quantizer is
1123                     * specified thanks to zones */
1124                    if (s->zone_mode == XVID_ZONE_QUANT) {
1125                            s->scaled_length = s->length;
1126                            continue;
1127                    }
1128    
1129                    /* Compute the scaled length */
1130                    len = (int)((double)s->length * scaler * s->weight / rc->avg_weight);
1131    
1132                    /* Compare with the computed minimum */
1133                    if (len < rc->min_length[s->type-1]) {
1134                            /* This is a 'forced size' frame, set its frame size to the
1135                             * computed minimum */
1136                            s->scaled_length = rc->min_length[s->type-1];
1137    
1138                            /* Remove both scaled and original size from their respective
1139                             * total counters, as we prepare a second pass for 'regular'
1140                             * frames */
1141                            target -= s->scaled_length;
1142                            pass1_length -= s->length;
1143                    } else {
1144                            /* Do nothing for now, we'll scale this later */
1145                            s->scaled_length = 0;
1146                    }
1147            }
1148    
1149            /* The first pass on data substracted all 'forced size' frames from the
1150             * total counters. Now, it's possible to scale the 'regular' frames. */
1151    
1152            /* Scaling factor for 'regular' frames */
1153            scaler = (double)target / (double)pass1_length;
1154    
1155            /* Detect undersizing */
1156            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1157                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected after correction\n");
1158                    scaler = 1.0;
1159            }
1160    
1161            /* Do another pass with the new scaler */
1162            for (i=0; i<rc->num_frames; i++) {
1163                    twopass_stat_t * s = &rc->stats[i];
1164    
1165                    /* Ignore frame with forced frame sizes */
1166                    if (s->scaled_length == 0)
1167                            s->scaled_length = (int)((double)s->length * scaler * s->weight / rc->avg_weight);
1168            }
1169    
1170            /* Job done */
1171            return;
1172    }
1173    
1174    /* Apply all user settings to the scaled curve
1175     * This implies:
1176     *   keyframe boosting
1177     *   high/low compression */
1178    static void
1179    scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)
1180    {
1181            int i;
1182            int64_t ivop_boost_total;
1183    
1184            /* Reset the rate controller (per frame type) total byte counters */
1185            for (i=0; i<3; i++) rc->tot_scaled_length[i] = 0;
1186    
1187            /* Compute total bytes for each frame type */
1188            for (i=0; i<rc->num_frames;i++) {
1189                    twopass_stat_t *s = &rc->stats[i];
1190                    rc->tot_scaled_length[s->type-1] += s->scaled_length;
1191            }
1192    
1193            /* First we compute the total amount of bits needed, as being described by
1194             * the scaled distribution. During this pass over the complete stats data,
1195             * we see how much bits two user settings will get/give from/to p&b frames:
1196             *  - keyframe boosting
1197             *  - keyframe distance penalty */
1198            rc->KF_idx = 0;
1199            ivop_boost_total = 0;
1200            for (i=0; i<rc->num_frames; i++) {
1201                    twopass_stat_t * s = &rc->stats[i];
1202    
1203                    /* Some more work is needed for I frames */
1204                    if (s->type == XVID_TYPE_IVOP) {
1205                            int ivop_boost;
1206    
1207                            /* Accumulate bytes needed for keyframe boosting */
1208                            ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;
1209    
1210    #if 0 /* ToDo: decide how to apply kfthresholding */
1211    #endif
1212                            /* If the frame size drops under the minimum length, then cap ivop_boost */
1213                            if (ivop_boost + s->scaled_length < rc->min_length[XVID_TYPE_IVOP-1])
1214                                    ivop_boost = rc->min_length[XVID_TYPE_IVOP-1] - s->scaled_length;
1215    
1216                            /* Accumulate the ivop boost */
1217                            ivop_boost_total += ivop_boost;
1218    
1219                            /* Don't forget to update the keyframe index */
1220                            rc->KF_idx++;
1221                    }
1222            }
1223    
1224            /* Initialize the IBoost tax ratio for P/S/B frames
1225             *
1226             * This ratio has to be applied to p/b/s frames in order to reserve
1227             * additional bits for keyframes (keyframe boosting) or if too much
1228             * keyframe distance is applied, bits retrieved from the keyframes.
1229             *
1230             * ie pb_length *= rc->pb_iboost_tax_ratio;
1231             *
1232             *    gives the ideal length of a p/b frame */
1233    
1234            /* Compute the total length of p/b/s frames (temporary storage into
1235             * movie_curve) */
1236            rc->pb_iboost_tax_ratio  = (double)rc->tot_scaled_length[XVID_TYPE_PVOP-1];
1237            rc->pb_iboost_tax_ratio += (double)rc->tot_scaled_length[XVID_TYPE_BVOP-1];
1238    
1239            /* Compute the ratio described above
1240             *     taxed_total = sum(0, n, tax*scaled_length)
1241             * <=> taxed_total = tax.sum(0, n, scaled_length)
1242             * <=> tax = taxed_total / original_total */
1243            rc->pb_iboost_tax_ratio =
1244                    (rc->pb_iboost_tax_ratio - ivop_boost_total) /
1245                    rc->pb_iboost_tax_ratio;
1246    
1247            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- IFrame boost tax ratio:%.2f\n",
1248                            rc->pb_iboost_tax_ratio);
1249    
1250            /* Compute the average size of frames per frame type */
1251            for(i=0; i<3; i++) {
1252                    /* Special case for missing type or weird case */
1253                    if (rc->count[i] == 0 || rc->pb_iboost_tax_ratio == 0) {
1254                            rc->avg_length[i] = 1;
1255                    } else {
1256                            rc->avg_length[i] = rc->tot_scaled_length[i];
1257    
1258                            if (i == (XVID_TYPE_IVOP-1)) {
1259                                    /* I Frames total has to be added the boost total */
1260                                    rc->avg_length[i] += ivop_boost_total;
1261                            } else {
1262                                    /* P/B frames has to taxed */
1263                                    rc->avg_length[i] *= rc->pb_iboost_tax_ratio;
1264                            }
1265    
1266                            /* Finally compute the average frame size */
1267                            rc->avg_length[i] /= (double)rc->count[i];
1268                    }
1269            }
1270    
1271            /* Assymetric curve compression */
1272            if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
1273                    double symetric_total;
1274                    double assymetric_delta_total;
1275    
1276                    /* Like I frame boosting, assymetric curve compression modifies the total
1277                     * amount of needed bits, we must compute the ratio so we can prescale
1278                     lengths */
1279                    symetric_total = 0;
1280                    assymetric_delta_total = 0;
1281                    for (i=0; i<rc->num_frames; i++) {
1282                            double assymetric_delta;
1283                            double dbytes;
1284                            twopass_stat_t * s = &rc->stats[i];
1285    
1286                            /* I Frames are not concerned by assymetric scaling */
1287                            if (s->type == XVID_TYPE_IVOP)
1288                                    continue;
1289    
1290                            /* During the real run, we would have to apply the iboost tax */
1291                            dbytes = s->scaled_length * rc->pb_iboost_tax_ratio;
1292    
1293                            /* Update the symmetric curve compression total */
1294                            symetric_total += dbytes;
1295    
1296                            /* Apply assymetric curve compression */
1297                            if (dbytes > rc->avg_length[s->type-1])
1298                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_high / 100.0f;
1299                            else
1300                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_low  / 100.0f;
1301    
1302                            /* Cap to the minimum frame size if needed */
1303                            if (dbytes + assymetric_delta < rc->min_length[s->type-1])
1304                                    assymetric_delta = rc->min_length[s->type-1] - dbytes;
1305    
1306                            /* Accumulate after assymetric curve compression */
1307                            assymetric_delta_total += assymetric_delta;
1308                    }
1309    
1310                    /* Compute the tax that all p/b frames have to pay in order to respect the
1311                     * bit distribution changes that the assymetric compression curve imposes
1312                     * We want assymetric_total = sum(0, n-1, tax.scaled_length)
1313                     *      ie assymetric_total = ratio.sum(0, n-1, scaled_length)
1314                     *         ratio = assymetric_total / symmetric_total */
1315                    rc->assymetric_tax_ratio = ((double)symetric_total - (double)assymetric_delta_total) / (double)symetric_total;
1316            } else {
1317                    rc->assymetric_tax_ratio = 1.0f;
1318            }
1319    
1320            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Assymetric tax ratio:%.2f\n", rc->assymetric_tax_ratio);
1321    
1322            /* Last bits that need to be reset */
1323            rc->overflow = 0;
1324            rc->KFoverflow = 0;
1325            rc->KFoverflow_partial = 0;
1326            rc->KF_idx = 0;
1327            rc->desired_total = 0;
1328            rc->real_total = 0;
1329    
1330            /* Job done */
1331            return;
1332    }
1333    
1334    /*****************************************************************************
1335     * Still more low level stuff (nothing to do with stats treatment)
1336     ****************************************************************************/
1337    
1338    /* This function returns an allocated string containing a complete line read
1339     * from the file starting at the current position */
1340    static char *
1341    readline(FILE *f)
1342    {
1343            char *buffer = NULL;
1344            int buffer_size = 0;
1345            int pos = 0;
1346    
1347            do {
1348                    int c;
1349    
1350                    /* Read a character from the stream */
1351                    c = fgetc(f);
1352    
1353                    /* Is that EOF or new line ? */
1354                    if(c == EOF || c == '\n')
1355                            break;
1356    
1357                    /* Do we have to update buffer ? */
1358                    if(pos >= buffer_size - 1) {
1359                            buffer_size += BUF_SZ;
1360                            buffer = (char*)realloc(buffer, buffer_size);
1361                            if (buffer == NULL)
1362                                    return(NULL);
1363                    }
1364    
1365                    buffer[pos] = c;
1366                    pos++;
1367            } while(1);
1368    
1369            /* Read \n or EOF */
1370            if (buffer == NULL) {
1371                    /* EOF, so we reached the end of the file, return NULL */
1372                    if(feof(f))
1373                            return(NULL);
1374    
1375                    /* Just an empty line with just a newline, allocate a 1 byte buffer to
1376                     * store a zero length string */
1377                    buffer = (char*)malloc(1);
1378                    if(buffer == NULL)
1379                            return(NULL);
1380            }
1381    
1382            /* Zero terminated string */
1383            buffer[pos] = '\0';
1384    
1385            return(buffer);
1386    }
1387    
1388    /* This function returns a pointer to the first non space char in the given
1389     * string */
1390    static char *
1391    skipspaces(char *string)
1392    {
1393            const char spaces[] =
1394                    {
1395                            ' ','\t','\0'
1396                    };
1397            const char *spacechar = spaces;
1398    
1399            if (string == NULL) return(NULL);
1400    
1401            while (*string != '\0') {
1402                    /* Test against space chars */
1403                    while (*spacechar != '\0') {
1404                            if (*string == *spacechar) {
1405                                    string++;
1406                                    spacechar = spaces;
1407                                    break;
1408                            }
1409                            spacechar++;
1410                    }
1411    
1412                    /* No space char */
1413                    if (*spacechar == '\0') return(string);
1414            }
1415    
1416            return(string);
1417    }
1418    
1419    /* This function returns a boolean that tells if the string is only a
1420     * comment */
1421    static int
1422    iscomment(char *string)
1423    {
1424            const char comments[] =
1425                    {
1426                            '#',';', '%', '\0'
1427                    };
1428            const char *cmtchar = comments;
1429            int iscomment = 0;
1430    
1431            if (string == NULL) return(1);
1432    
1433            string = skipspaces(string);
1434    
1435            while(*cmtchar != '\0') {
1436                    if(*string == *cmtchar) {
1437                            iscomment = 1;
1438                            break;
1439                    }
1440                    cmtchar++;
1441            }
1442    
1443            return(iscomment);
1444    }
1445    
1446    #if 0
1447    static void
1448    stats_print(rc_2pass2_t * rc)
1449    {
1450            int i;
1451            const char frame_type[4] = { 'i', 'p', 'b', 's'};
1452    
1453            for (i=0; i<rc->num_frames; i++) {
1454                    twopass_stat_t *s = &rc->stats[i];
1455                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- frame:%d type:%c quant:%d stats:%d scaled:%d desired:%d actual:%d overflow(%c):%.2f\n",
1456                                    i, frame_type[s->type-1], -1, s->length, s->scaled_length,
1457                                    s->desired_length, -1, frame_type[s->type-1], -1.0f);
1458            }
1459    }
1460    #endif
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