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revision 1.1, Tue Mar 25 10:58:33 2003 UTC revision 1.1.2.30, Mon Dec 8 12:38:04 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: insufficent stats data */
440            if (data->frame_num >= rc->num_frames) {
441                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- stats file too short (now processing frame %d)",
442                            data->frame_num);
443                    return(0);
444            }
445    
446            /* Third case: We are in a Quant zone */
447            if (s->zone_mode == XVID_ZONE_QUANT) {
448                    rc->fq_error += s->weight;
449                    data->quant = (int)rc->fq_error;
450                    rc->fq_error -= data->quant;
451    
452                    s->desired_length = s->length;
453    
454                    return(0);
455            }
456    
457    
458            /*************************************************************************/
459            /*************************************************************************/
460            /*************************************************************************/
461    
462            /*-------------------------------------------------------------------------
463             * Frame bit allocation first part
464             *
465             * First steps apply user settings, just like it is done in the theoritical
466             * scaled_curve_apply_advanced_parameters
467             *-----------------------------------------------------------------------*/
468    
469            /* Set desired to what we are wanting to obtain for this frame */
470            dbytes = (double)s->scaled_length;
471    
472            /* IFrame user settings*/
473            if (s->type == XVID_TYPE_IVOP) {
474                    /* Keyframe boosting -- All keyframes benefit from it */
475                    dbytes += dbytes*rc->param.keyframe_boost / 100;
476    
477    #if 0 /* ToDo: decide how to apply kfthresholding */
478    #endif
479            } else {
480    
481                    /* P/S/B frames must reserve some bits for iframe boosting */
482                    dbytes *= rc->pb_iboost_tax_ratio;
483    
484                    /* Apply assymetric curve compression */
485                    if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
486                            double assymetric_delta;
487    
488                            /* Compute the assymetric delta, this is computed before applying
489                             * the tax, as done in the pre_process function */
490                            if (dbytes > rc->avg_length[s->type-1])
491                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_high / 100.0;
492                            else
493                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_low  / 100.0;
494    
495                            /* Now we must apply the assymetric tax, else our curve compression
496                             * would not give a theoritical target size equal to what it is
497                             * expected */
498                            dbytes *= rc->assymetric_tax_ratio;
499    
500                            /* Now we can add the assymetric delta */
501                            dbytes += assymetric_delta;
502                    }
503            }
504    
505            /* That is what we would like to have -- Don't put that chunk after
506             * overflow control, otherwise, overflow is counted twice and you obtain
507             * half sized bitrate sequences */
508            s->desired_length  = (int)dbytes;
509            rc->desired_total += dbytes;
510    
511            /*------------------------------------------------------------------------
512             * Frame bit allocation: overflow control part.
513             *
514             * Unlike the theoritical scaled_curve_apply_advanced_parameters, here
515             * it's real encoding and we need to make sure we don't go so far from
516             * what is our ideal scaled curve.
517             *-----------------------------------------------------------------------*/
518    
519            /* Compute the overflow we should compensate */
520            if (s->type != XVID_TYPE_IVOP) {
521                    double frametype_factor;
522                    double framesize_factor;
523    
524                    /* Take only the desired part of overflow */
525                    overflow = rc->overflow;
526    
527                    /* Factor that will take care to decrease the overflow applied
528                     * according to the importance of this frame type in term of
529                     * overall size */
530                    frametype_factor  = rc->count[XVID_TYPE_IVOP-1]*rc->avg_length[XVID_TYPE_IVOP-1];
531                    frametype_factor += rc->count[XVID_TYPE_PVOP-1]*rc->avg_length[XVID_TYPE_PVOP-1];
532                    frametype_factor += rc->count[XVID_TYPE_BVOP-1]*rc->avg_length[XVID_TYPE_BVOP-1];
533                    frametype_factor /= rc->count[s->type-1]*rc->avg_length[s->type-1];
534                    frametype_factor  = 1/frametype_factor;
535    
536                    /* Factor that will take care not to compensate too much for this frame
537                     * size */
538                    framesize_factor  = dbytes;
539                    framesize_factor /= rc->avg_length[s->type-1];
540    
541                    /* Treat only the overflow part concerned by this frame type and size */
542                    overflow *= frametype_factor;
543    #if 0
544                    /* Leave this one alone, as it impacts badly on quality */
545                    overflow *= framesize_factor;
546    #endif
547    
548                    /* Apply the overflow strength imposed by the user */
549                    overflow *= (rc->param.overflow_control_strength/100.0f);
550            } else {
551                    /* no overflow applied in IFrames because:
552                     *  - their role is important as they're references for P/BFrames.
553                     *  - there aren't much in typical sequences, so if an IFrame overflows too
554                     *    much, this overflow may impact the next IFrame too much and generate
555                     *    a sequence of poor quality frames */
556                    overflow = 0;
557            }
558    
559            /* Make sure we are not trying to compensate more overflow than we even have */
560            if (fabs(overflow) > fabs(rc->overflow))
561                    overflow = rc->overflow;
562    
563            /* Make sure the overflow doesn't make the frame size to get out of the range
564             * [-max_degradation..+max_improvment] */
565            if (overflow > dbytes*rc->param.max_overflow_improvement / 100) {
566                    if(overflow <= dbytes)
567                            dbytes += dbytes * rc->param.max_overflow_improvement / 100;
568                    else
569                            dbytes += overflow * rc->param.max_overflow_improvement / 100;
570            } else if (overflow < - dbytes * rc->param.max_overflow_degradation / 100) {
571                    dbytes -= dbytes * rc->param.max_overflow_degradation / 100;
572            } else {
573                    dbytes += overflow;
574            }
575    
576            /*-------------------------------------------------------------------------
577             * Frame bit allocation last part:
578             *
579             * Cap frame length so we don't reach neither bigger frame sizes than first
580             * pass nor smaller than the allowed minimum.
581             *-----------------------------------------------------------------------*/
582    
583            if (dbytes > s->length) {
584                    dbytes = s->length;
585            } else if (dbytes < rc->min_length[s->type-1]) {
586                    dbytes = rc->min_length[s->type-1];
587            } else if (dbytes > rc->max_length) {
588                    /* ToDo: this condition is always wrong as max_length == maximum frame
589                     * length of first pass, so the first condition already caps the frame
590                     * size... */
591                    capped_to_max_framesize = 1;
592                    dbytes = rc->max_length;
593                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- frame:%d Capped to maximum frame size\n",
594                                    data->frame_num);
595            }
596    
597            /*------------------------------------------------------------------------
598             * Desired frame length <-> quantizer mapping
599             *-----------------------------------------------------------------------*/
600    
601            /* For bframes we must retrieve the original quant used (sent to xvidcore)
602             * as core applies the bquant formula before writing the stat log entry */
603            if(s->type == XVID_TYPE_BVOP) {
604    
605                    twopass_stat_t *b_ref = s;
606    
607                    /* Find the reference frame */
608                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
609                            b_ref--;
610    
611                    /* Compute the original quant */
612                    s->quant  = 2*(100*s->quant - data->bquant_offset);
613                    s->quant += data->bquant_ratio - 1; /* to avoid rouding issues */
614                    s->quant  = s->quant/data->bquant_ratio - b_ref->quant;
615            }
616    
617            /* Don't laugh at this very 'simple' quant<->filesize relationship, it
618             * proves to be acurate enough for our algorithm */
619            scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;
620    
621    #ifdef COMPENSATE_FORMULA
622            /* We know xvidcore will apply the bframe formula again, so we compensate
623             * it right now to make sure we would not apply it twice */
624            if(s->type == XVID_TYPE_BVOP) {
625    
626                    twopass_stat_t *b_ref = s;
627    
628                    /* Find the reference frame */
629                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
630                            b_ref--;
631    
632                    /* Compute the quant it would be if the core did not apply the bframe
633                     * formula */
634                    scaled_quant  = 100*scaled_quant - data->bquant_offset;
635                    scaled_quant += data->bquant_ratio - 1; /* to avoid rouding issues */
636                    scaled_quant /= data->bquant_ratio;
637            }
638    #endif
639    
640            /* Quantizer has been scaled using floating point operations/results, we
641             * must cast it to integer */
642            data->quant = (int)scaled_quant;
643    
644            /* Let's clip the computed quantizer, if needed */
645            if (data->quant < 1) {
646                    data->quant = 1;
647            } else if (data->quant > 31) {
648                    data->quant = 31;
649            } else {
650    
651                    /* The frame quantizer has not been clipped, this appears to be a good
652                     * computed quantizer, do not loose quantizer decimal part that we
653                     * accumulate for later reuse when its sum represents a complete
654                     * unit. */
655                    rc->quant_error[s->type-1][data->quant] += scaled_quant - (double)data->quant;
656    
657                    if (rc->quant_error[s->type-1][data->quant] >= 1.0) {
658                            rc->quant_error[s->type-1][data->quant] -= 1.0;
659                            data->quant++;
660                    } else if (rc->quant_error[s->type-1][data->quant] <= -1.0) {
661                            rc->quant_error[s->type-1][data->quant] += 1.0;
662                            data->quant--;
663                    }
664            }
665    
666            /* Now we have a computed quant that is in the right quante range, with a
667             * possible +1 correction due to cumulated error. We can now safely clip
668             * the quantizer again with user's quant ranges. "Safely" means the Rate
669             * Control could learn more about this quantizer, this knowledge is useful
670             * for future frames even if it this quantizer won't be really used atm,
671             * that's why we don't perform this clipping earlier. */
672            if (data->quant < data->min_quant[s->type-1]) {
673                    data->quant = data->min_quant[s->type-1];
674            } else if (data->quant > data->max_quant[s->type-1]) {
675                    data->quant = data->max_quant[s->type-1];
676            }
677    
678            /* To avoid big quality jumps from frame to frame, we apply a "security"
679             * rule that makes |last_quant - new_quant| <= 2. This rule only applies
680             * to predicted frames (P and B) */
681            if (s->type != XVID_TYPE_IVOP && rc->last_quant[s->type-1] && capped_to_max_framesize == 0) {
682    
683                    if (data->quant > rc->last_quant[s->type-1] + 2) {
684                            data->quant = rc->last_quant[s->type-1] + 2;
685                            DPRINTF(XVID_DEBUG_RC,
686                                            "[xvid rc] -- frame %d p/b-frame quantizer prevented from rising too steeply\n",
687                                            data->frame_num);
688                    }
689                    if (data->quant < rc->last_quant[s->type-1] - 2) {
690                            data->quant = rc->last_quant[s->type-1] - 2;
691                            DPRINTF(XVID_DEBUG_RC,
692                                            "[xvid rc] -- frame:%d p/b-frame quantizer prevented from falling too steeply\n",
693                                            data->frame_num);
694                    }
695            }
696    
697            /* We don't want to pollute the RC histerisis when our computed quant has
698             * been computed from a capped frame size */
699            if (capped_to_max_framesize == 0)
700                    rc->last_quant[s->type-1] = data->quant;
701    
702            /* Don't forget to force 1st pass frame type ;-) */
703            data->type = s->type;
704    
705            /* Store the quantizer into the statistics -- Used to compensate the double
706             * formula symptom */
707            s->quant2 = data->quant;
708    
709            return 0;
710    }
711    
712    /*----------------------------------------------------------------------------
713     *--------------------------------------------------------------------------*/
714    
715    static int
716    rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data)
717    {
718            const char frame_type[4] = { 'i', 'p', 'b', 's'};
719            twopass_stat_t * s = &rc->stats[data->frame_num];
720    
721            /* Insufficent stats data */
722            if (data->frame_num >= rc->num_frames)
723                    return 0;
724    
725            /* Update the quantizer counter */
726            rc->quant_count[s->type-1][data->quant]++;
727    
728            /* Update the frame type overflow */
729            if (data->type == XVID_TYPE_IVOP) {
730                    int kfdiff = 0;
731    
732                    if(rc->KF_idx != rc->num_frames -1) {
733                            kfdiff  = rc->keyframe_locations[rc->KF_idx+1];
734                            kfdiff -= rc->keyframe_locations[rc->KF_idx];
735                    }
736    
737                    /* Flush Keyframe overflow accumulator */
738                    rc->overflow += rc->KFoverflow;
739    
740                    /* Store the frame overflow to the keyframe accumulator */
741                    rc->KFoverflow = s->desired_length - data->length;
742    
743                    if (kfdiff > 1) {
744                            /* Non-consecutive keyframes case:
745                             * We can then divide this total keyframe overflow into equal parts
746                             * that we will distribute into regular overflow at each frame
747                             * between the sequence bounded by two IFrames */
748                            rc->KFoverflow_partial = rc->KFoverflow / (kfdiff - 1);
749                    } else {
750                            /* Consecutive keyframes case:
751                             * Flush immediatly the keyframe overflow and reset keyframe
752                             * overflow */
753                            rc->overflow += rc->KFoverflow;
754                            rc->KFoverflow = 0;
755                            rc->KFoverflow_partial = 0;
756                    }
757                    rc->KF_idx++;
758            } else {
759                    /* Accumulate the frame overflow */
760                    rc->overflow += s->desired_length - data->length;
761    
762                    /* Distribute part of the keyframe overflow */
763                    rc->overflow += rc->KFoverflow_partial;
764    
765                    /* Don't forget to substract that same amount from the total keyframe
766                     * overflow */
767                    rc->KFoverflow -= rc->KFoverflow_partial;
768            }
769    
770            rc->overflow += s->error = s->desired_length - data->length;
771            rc->real_total += data->length;
772    
773            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",
774                            data->frame_num,
775                            frame_type[data->type-1],
776                            data->quant,
777                            s->length,
778                            s->scaled_length,
779                            s->desired_length,
780                            s->desired_length - s->error,
781                            -s->error,
782                            rc->overflow);
783    
784            return(0);
785    }
786    
787    /*****************************************************************************
788     * Helper functions definition
789     ****************************************************************************/
790    
791    /* Default buffer size for reading lines */
792    #define BUF_SZ   1024
793    
794    /* Helper functions for reading/parsing the stats file */
795    static char *skipspaces(char *string);
796    static int iscomment(char *string);
797    static char *readline(FILE *f);
798    
799    /* This function counts the number of frame entries in the stats file
800     * It also counts the number of I Frames */
801    static int
802    statsfile_count_frames(rc_2pass2_t * rc, char * filename)
803    {
804            FILE * f;
805            char *line;
806            int lines;
807    
808            rc->num_frames = 0;
809            rc->num_keyframes = 0;
810    
811            if ((f = fopen(filename, "rb")) == NULL)
812                    return(-1);
813    
814            lines = 0;
815            while ((line = readline(f)) != NULL) {
816    
817                    char *ptr;
818                    char type;
819                    int fields;
820    
821                    lines++;
822    
823                    /* We skip spaces */
824                    ptr = skipspaces(line);
825    
826                    /* Skip coment lines or empty lines */
827                    if(iscomment(ptr) || *ptr == '\0') {
828                            free(line);
829                            continue;
830                    }
831    
832                    /* Read the stat line from buffer */
833                    fields = sscanf(ptr, "%c", &type);
834    
835                    /* Valid stats files have at least 6 fields */
836                    if (fields == 1) {
837                            switch(type) {
838                            case 'i':
839                            case 'I':
840                                    rc->num_keyframes++;
841                            case 'p':
842                            case 'P':
843                            case 'b':
844                            case 'B':
845                            case 's':
846                            case 'S':
847                                    rc->num_frames++;
848                                    break;
849                            default:
850                                    DPRINTF(XVID_DEBUG_RC,
851                                                    "[xvid rc] -- WARNING: L%d unknown frame type used (%c).\n",
852                                                    lines, type);
853                            }
854                    } else {
855                                    DPRINTF(XVID_DEBUG_RC,
856                                                    "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",
857                                                    lines, 6-fields);
858                    }
859    
860                    /* Free the line buffer */
861                    free(line);
862            }
863    
864            /* We are done with the file */
865            fclose(f);
866    
867            return(0);
868    }
869    
870    /* open stats file(s) and read into rc->stats array */
871    static int
872    statsfile_load(rc_2pass2_t *rc, char * filename)
873    {
874            FILE * f;
875            int processed_entries;
876    
877            /* Opens the file */
878            if ((f = fopen(filename, "rb"))==NULL)
879                    return(-1);
880    
881            processed_entries = 0;
882            while(processed_entries < rc->num_frames) {
883                    char type;
884                    int fields;
885                    twopass_stat_t * s = &rc->stats[processed_entries];
886                    char *line, *ptr;
887    
888                    /* Read the line from the file */
889                    if((line = readline(f)) == NULL)
890                            break;
891    
892                    /* We skip spaces */
893                    ptr = skipspaces(line);
894    
895                    /* Skip comment lines or empty lines */
896                    if(iscomment(ptr) || *ptr == '\0') {
897                            free(line);
898                            continue;
899                    }
900    
901                    /* Reset this field that is optional */
902                    s->scaled_length = 0;
903    
904                    /* Convert the fields */
905                    fields = sscanf(ptr,
906                                                    "%c %d %d %d %d %d %d\n",
907                                                    &type,
908                                                    &s->quant,
909                                                    &s->blks[0], &s->blks[1], &s->blks[2],
910                                                    &s->length,
911                                                    &s->scaled_length);
912    
913                    /* Free line buffer, we don't need it anymore */
914                    free(line);
915    
916                    /* Fail silently, this has probably been warned in
917                     * statsfile_count_frames */
918                    if(fields != 6 && fields != 7)
919                            continue;
920    
921                    /* Convert frame type */
922                    switch(type) {
923                    case 'i':
924                    case 'I':
925                            s->type = XVID_TYPE_IVOP;
926                            break;
927                    case 'p':
928                    case 'P':
929                    case 's':
930                    case 'S':
931                            s->type = XVID_TYPE_PVOP;
932                            break;
933                    case 'b':
934                    case 'B':
935                            s->type = XVID_TYPE_BVOP;
936                            break;
937                    default:
938                            /* Same as before, fail silently */
939                            continue;
940                    }
941    
942                    /* Ok it seems it's been processed correctly */
943                    processed_entries++;
944            }
945    
946            /* Close the file */
947            fclose(f);
948    
949            return(0);
950    }
951    
952    /* pre-process the statistics data
953     * - for each type, count, tot_length, min_length, max_length
954     * - set keyframes_locations */
955    static void
956    first_pass_stats_prepare_data(rc_2pass2_t * rc)
957    {
958            int i,j;
959    
960            /* *rc fields initialization
961             * NB: INT_MAX and INT_MIN are used in order to be immediately replaced
962             *     with real values of the 1pass */
963            for (i=0; i<3; i++) {
964                    rc->count[i]=0;
965                    rc->tot_length[i] = 0;
966                    rc->min_length[i] = INT_MAX;
967            }
968    
969            rc->max_length = INT_MIN;
970    
971            /* Loop through all frames and find/compute all the stuff this function
972             * is supposed to do */
973            for (i=j=0; i<rc->num_frames; i++) {
974                    twopass_stat_t * s = &rc->stats[i];
975    
976                    rc->count[s->type-1]++;
977                    rc->tot_length[s->type-1] += s->length;
978    
979                    if (s->length < rc->min_length[s->type-1]) {
980                            rc->min_length[s->type-1] = s->length;
981                    }
982    
983                    if (s->length > rc->max_length) {
984                            rc->max_length = s->length;
985                    }
986    
987                    if (s->type == XVID_TYPE_IVOP) {
988                            rc->keyframe_locations[j] = i;
989                            j++;
990                    }
991            }
992    
993            /* NB:
994             * The "per sequence" overflow system considers a natural sequence to be
995             * formed by all frames between two iframes, so if we want to make sure
996             * the system does not go nuts during last sequence, we force the last
997             * frame to appear in the keyframe locations array. */
998            rc->keyframe_locations[j] = i;
999    
1000            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass IFrame length: %d\n", rc->min_length[0]);
1001            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass PFrame length: %d\n", rc->min_length[1]);
1002            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass BFrame length: %d\n", rc->min_length[2]);
1003    }
1004    
1005    /* calculate zone weight "center" */
1006    static void
1007    zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create)
1008    {
1009            int i,j;
1010            int n = 0;
1011    
1012            rc->avg_weight = 0.0;
1013            rc->tot_quant = 0;
1014    
1015    
1016            if (create->num_zones == 0) {
1017                    for (j = 0; j < rc->num_frames; j++) {
1018                            rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1019                            rc->stats[j].weight = 1.0;
1020                    }
1021                    rc->avg_weight += rc->num_frames * 1.0;
1022                    n += rc->num_frames;
1023            }
1024    
1025    
1026            for(i=0; i < create->num_zones; i++) {
1027    
1028                    int next = (i+1<create->num_zones) ? create->zones[i+1].frame : rc->num_frames;
1029    
1030                    if (i==0 && create->zones[i].frame > 0) {
1031                            for (j = 0; j < create->zones[i].frame && j < rc->num_frames; j++) {
1032                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1033                                    rc->stats[j].weight = 1.0;
1034                            }
1035                            rc->avg_weight += create->zones[i].frame * 1.0;
1036                            n += create->zones[i].frame;
1037                    }
1038    
1039                    if (create->zones[i].mode == XVID_ZONE_WEIGHT) {
1040                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1041                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1042                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1043                            }
1044                            next -= create->zones[i].frame;
1045                            rc->avg_weight += (double)(next * create->zones[i].increment) / (double)create->zones[i].base;
1046                            n += next;
1047                    }else{  /* XVID_ZONE_QUANT */
1048                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1049                                    rc->stats[j].zone_mode = XVID_ZONE_QUANT;
1050                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1051                                    rc->tot_quant += rc->stats[j].length;
1052                            }
1053                    }
1054            }
1055            rc->avg_weight = n>0 ? rc->avg_weight/n : 1.0;
1056    
1057            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- center_weight:%f (for %d frames)  fixed_bytes:%d\n", rc->avg_weight, n, rc->tot_quant);
1058    }
1059    
1060    
1061    /* scale the curve */
1062    static void
1063    first_pass_scale_curve_internal(rc_2pass2_t *rc)
1064    {
1065            int64_t target;
1066            int64_t pass1_length;
1067            double scaler;
1068            int i, num_MBs;
1069    
1070            /* We remove the bytes used by the fixed quantizer zones
1071             * ToDo: this approach is flawed, the same amount of bytes is removed from
1072             *       target and first pass data, this has no sense, zone_process should
1073             *       give us two results one for unscaled data (1pass) and the other
1074             *       one for scaled data and we should then write:
1075             *       target = rc->target - rc->tot_quant_scaled;
1076             *       pass1_length = rc->i+p+b - rc->tot_quant_firstpass */
1077            target = rc->target - rc->tot_quant;
1078    
1079            /* Do the same for the first pass data */
1080            pass1_length  = rc->tot_length[XVID_TYPE_IVOP-1];
1081            pass1_length += rc->tot_length[XVID_TYPE_PVOP-1];
1082            pass1_length += rc->tot_length[XVID_TYPE_BVOP-1];
1083            pass1_length -= rc->tot_quant;
1084    
1085            /* Let's compute a linear scaler in order to perform curve scaling */
1086            scaler = (double)target / (double)pass1_length;
1087    
1088            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1089                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected before correction\n");
1090                    scaler = 1.0;
1091            }
1092    
1093            /* Compute min frame lengths (for each frame type) according to the number
1094             * of MBs. We sum all block type counters of frame 0, this gives us the
1095             * number of MBs.
1096             *
1097             * We compare these hardcoded values with observed values in first pass
1098             * (determined in pre_process0).Then we keep the real minimum. */
1099    
1100            /* Number of MBs */
1101            num_MBs  = rc->stats[0].blks[0];
1102            num_MBs += rc->stats[0].blks[1];
1103            num_MBs += rc->stats[0].blks[2];
1104    
1105            /* Minimum for I frames */
1106            if(rc->min_length[XVID_TYPE_IVOP-1] > ((num_MBs*22) + 240) / 8)
1107                    rc->min_length[XVID_TYPE_IVOP-1] = ((num_MBs*22) + 240) / 8;
1108    
1109            /* Minimum for P/S frames */
1110            if(rc->min_length[XVID_TYPE_PVOP-1] > ((num_MBs) + 88)  / 8)
1111                    rc->min_length[XVID_TYPE_PVOP-1] = ((num_MBs) + 88)  / 8;
1112    
1113            /* Minimum for B frames */
1114            if(rc->min_length[XVID_TYPE_BVOP-1] > 8)
1115                    rc->min_length[XVID_TYPE_BVOP-1] = 8;
1116    
1117            /* Perform an initial scale pass.
1118             *
1119             * If a frame size is scaled underneath our hardcoded minimums, then we
1120             * force the frame size to the minimum, and deduct the original & scaled
1121             * frame length from the original and target total lengths */
1122            for (i=0; i<rc->num_frames; i++) {
1123                    twopass_stat_t * s = &rc->stats[i];
1124                    int len;
1125    
1126                    /* No need to scale frame length for which a specific quantizer is
1127                     * specified thanks to zones */
1128                    if (s->zone_mode == XVID_ZONE_QUANT) {
1129                            s->scaled_length = s->length;
1130                            continue;
1131                    }
1132    
1133                    /* Compute the scaled length */
1134                    len = (int)((double)s->length * scaler * s->weight / rc->avg_weight);
1135    
1136                    /* Compare with the computed minimum */
1137                    if (len < rc->min_length[s->type-1]) {
1138                            /* This is a 'forced size' frame, set its frame size to the
1139                             * computed minimum */
1140                            s->scaled_length = rc->min_length[s->type-1];
1141    
1142                            /* Remove both scaled and original size from their respective
1143                             * total counters, as we prepare a second pass for 'regular'
1144                             * frames */
1145                            target -= s->scaled_length;
1146                            pass1_length -= s->length;
1147                    } else {
1148                            /* Do nothing for now, we'll scale this later */
1149                            s->scaled_length = 0;
1150                    }
1151            }
1152    
1153            /* The first pass on data substracted all 'forced size' frames from the
1154             * total counters. Now, it's possible to scale the 'regular' frames. */
1155    
1156            /* Scaling factor for 'regular' frames */
1157            scaler = (double)target / (double)pass1_length;
1158    
1159            /* Detect undersizing */
1160            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1161                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected after correction\n");
1162                    scaler = 1.0;
1163            }
1164    
1165            /* Do another pass with the new scaler */
1166            for (i=0; i<rc->num_frames; i++) {
1167                    twopass_stat_t * s = &rc->stats[i];
1168    
1169                    /* Ignore frame with forced frame sizes */
1170                    if (s->scaled_length == 0)
1171                            s->scaled_length = (int)((double)s->length * scaler * s->weight / rc->avg_weight);
1172            }
1173    
1174            /* Job done */
1175            return;
1176    }
1177    
1178    /* Apply all user settings to the scaled curve
1179     * This implies:
1180     *   keyframe boosting
1181     *   high/low compression */
1182    static void
1183    scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)
1184    {
1185            int i;
1186            int64_t ivop_boost_total;
1187    
1188            /* Reset the rate controller (per frame type) total byte counters */
1189            for (i=0; i<3; i++) rc->tot_scaled_length[i] = 0;
1190    
1191            /* Compute total bytes for each frame type */
1192            for (i=0; i<rc->num_frames;i++) {
1193                    twopass_stat_t *s = &rc->stats[i];
1194                    rc->tot_scaled_length[s->type-1] += s->scaled_length;
1195            }
1196    
1197            /* First we compute the total amount of bits needed, as being described by
1198             * the scaled distribution. During this pass over the complete stats data,
1199             * we see how much bits two user settings will get/give from/to p&b frames:
1200             *  - keyframe boosting
1201             *  - keyframe distance penalty */
1202            rc->KF_idx = 0;
1203            ivop_boost_total = 0;
1204            for (i=0; i<rc->num_frames; i++) {
1205                    twopass_stat_t * s = &rc->stats[i];
1206    
1207                    /* Some more work is needed for I frames */
1208                    if (s->type == XVID_TYPE_IVOP) {
1209                            int ivop_boost;
1210    
1211                            /* Accumulate bytes needed for keyframe boosting */
1212                            ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;
1213    
1214    #if 0 /* ToDo: decide how to apply kfthresholding */
1215    #endif
1216                            /* If the frame size drops under the minimum length, then cap ivop_boost */
1217                            if (ivop_boost + s->scaled_length < rc->min_length[XVID_TYPE_IVOP-1])
1218                                    ivop_boost = rc->min_length[XVID_TYPE_IVOP-1] - s->scaled_length;
1219    
1220                            /* Accumulate the ivop boost */
1221                            ivop_boost_total += ivop_boost;
1222    
1223                            /* Don't forget to update the keyframe index */
1224                            rc->KF_idx++;
1225                    }
1226            }
1227    
1228            /* Initialize the IBoost tax ratio for P/S/B frames
1229             *
1230             * This ratio has to be applied to p/b/s frames in order to reserve
1231             * additional bits for keyframes (keyframe boosting) or if too much
1232             * keyframe distance is applied, bits retrieved from the keyframes.
1233             *
1234             * ie pb_length *= rc->pb_iboost_tax_ratio;
1235             *
1236             *    gives the ideal length of a p/b frame */
1237    
1238            /* Compute the total length of p/b/s frames (temporary storage into
1239             * movie_curve) */
1240            rc->pb_iboost_tax_ratio  = (double)rc->tot_scaled_length[XVID_TYPE_PVOP-1];
1241            rc->pb_iboost_tax_ratio += (double)rc->tot_scaled_length[XVID_TYPE_BVOP-1];
1242    
1243            /* Compute the ratio described above
1244             *     taxed_total = sum(0, n, tax*scaled_length)
1245             * <=> taxed_total = tax.sum(0, n, scaled_length)
1246             * <=> tax = taxed_total / original_total */
1247            rc->pb_iboost_tax_ratio =
1248                    (rc->pb_iboost_tax_ratio - ivop_boost_total) /
1249                    rc->pb_iboost_tax_ratio;
1250    
1251            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- IFrame boost tax ratio:%.2f\n",
1252                            rc->pb_iboost_tax_ratio);
1253    
1254            /* Compute the average size of frames per frame type */
1255            for(i=0; i<3; i++) {
1256                    /* Special case for missing type or weird case */
1257                    if (rc->count[i] == 0 || rc->pb_iboost_tax_ratio == 0) {
1258                            rc->avg_length[i] = 1;
1259                    } else {
1260                            rc->avg_length[i] = rc->tot_scaled_length[i];
1261    
1262                            if (i == (XVID_TYPE_IVOP-1)) {
1263                                    /* I Frames total has to be added the boost total */
1264                                    rc->avg_length[i] += ivop_boost_total;
1265                            } else {
1266                                    /* P/B frames has to taxed */
1267                                    rc->avg_length[i] *= rc->pb_iboost_tax_ratio;
1268                            }
1269    
1270                            /* Finally compute the average frame size */
1271                            rc->avg_length[i] /= (double)rc->count[i];
1272                    }
1273            }
1274    
1275            /* Assymetric curve compression */
1276            if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
1277                    double symetric_total;
1278                    double assymetric_delta_total;
1279    
1280                    /* Like I frame boosting, assymetric curve compression modifies the total
1281                     * amount of needed bits, we must compute the ratio so we can prescale
1282                     lengths */
1283                    symetric_total = 0;
1284                    assymetric_delta_total = 0;
1285                    for (i=0; i<rc->num_frames; i++) {
1286                            double assymetric_delta;
1287                            double dbytes;
1288                            twopass_stat_t * s = &rc->stats[i];
1289    
1290                            /* I Frames are not concerned by assymetric scaling */
1291                            if (s->type == XVID_TYPE_IVOP)
1292                                    continue;
1293    
1294                            /* During the real run, we would have to apply the iboost tax */
1295                            dbytes = s->scaled_length * rc->pb_iboost_tax_ratio;
1296    
1297                            /* Update the symmetric curve compression total */
1298                            symetric_total += dbytes;
1299    
1300                            /* Apply assymetric curve compression */
1301                            if (dbytes > rc->avg_length[s->type-1])
1302                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_high / 100.0f;
1303                            else
1304                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_low  / 100.0f;
1305    
1306                            /* Cap to the minimum frame size if needed */
1307                            if (dbytes + assymetric_delta < rc->min_length[s->type-1])
1308                                    assymetric_delta = rc->min_length[s->type-1] - dbytes;
1309    
1310                            /* Accumulate after assymetric curve compression */
1311                            assymetric_delta_total += assymetric_delta;
1312                    }
1313    
1314                    /* Compute the tax that all p/b frames have to pay in order to respect the
1315                     * bit distribution changes that the assymetric compression curve imposes
1316                     * We want assymetric_total = sum(0, n-1, tax.scaled_length)
1317                     *      ie assymetric_total = ratio.sum(0, n-1, scaled_length)
1318                     *         ratio = assymetric_total / symmetric_total */
1319                    rc->assymetric_tax_ratio = ((double)symetric_total - (double)assymetric_delta_total) / (double)symetric_total;
1320            } else {
1321                    rc->assymetric_tax_ratio = 1.0f;
1322            }
1323    
1324            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Assymetric tax ratio:%.2f\n", rc->assymetric_tax_ratio);
1325    
1326            /* Last bits that need to be reset */
1327            rc->overflow = 0;
1328            rc->KFoverflow = 0;
1329            rc->KFoverflow_partial = 0;
1330            rc->KF_idx = 0;
1331            rc->desired_total = 0;
1332            rc->real_total = 0;
1333    
1334            /* Job done */
1335            return;
1336    }
1337    
1338    /*****************************************************************************
1339     * Still more low level stuff (nothing to do with stats treatment)
1340     ****************************************************************************/
1341    
1342    /* This function returns an allocated string containing a complete line read
1343     * from the file starting at the current position */
1344    static char *
1345    readline(FILE *f)
1346    {
1347            char *buffer = NULL;
1348            int buffer_size = 0;
1349            int pos = 0;
1350    
1351            do {
1352                    int c;
1353    
1354                    /* Read a character from the stream */
1355                    c = fgetc(f);
1356    
1357                    /* Is that EOF or new line ? */
1358                    if(c == EOF || c == '\n')
1359                            break;
1360    
1361                    /* Do we have to update buffer ? */
1362                    if(pos >= buffer_size - 1) {
1363                            buffer_size += BUF_SZ;
1364                            buffer = (char*)realloc(buffer, buffer_size);
1365                            if (buffer == NULL)
1366                                    return(NULL);
1367                    }
1368    
1369                    buffer[pos] = c;
1370                    pos++;
1371            } while(1);
1372    
1373            /* Read \n or EOF */
1374            if (buffer == NULL) {
1375                    /* EOF, so we reached the end of the file, return NULL */
1376                    if(feof(f))
1377                            return(NULL);
1378    
1379                    /* Just an empty line with just a newline, allocate a 1 byte buffer to
1380                     * store a zero length string */
1381                    buffer = (char*)malloc(1);
1382                    if(buffer == NULL)
1383                            return(NULL);
1384            }
1385    
1386            /* Zero terminated string */
1387            buffer[pos] = '\0';
1388    
1389            return(buffer);
1390    }
1391    
1392    /* This function returns a pointer to the first non space char in the given
1393     * string */
1394    static char *
1395    skipspaces(char *string)
1396    {
1397            const char spaces[] =
1398                    {
1399                            ' ','\t','\0'
1400                    };
1401            const char *spacechar = spaces;
1402    
1403            if (string == NULL) return(NULL);
1404    
1405            while (*string != '\0') {
1406                    /* Test against space chars */
1407                    while (*spacechar != '\0') {
1408                            if (*string == *spacechar) {
1409                                    string++;
1410                                    spacechar = spaces;
1411                                    break;
1412                            }
1413                            spacechar++;
1414                    }
1415    
1416                    /* No space char */
1417                    if (*spacechar == '\0') return(string);
1418            }
1419    
1420            return(string);
1421    }
1422    
1423    /* This function returns a boolean that tells if the string is only a
1424     * comment */
1425    static int
1426    iscomment(char *string)
1427    {
1428            const char comments[] =
1429                    {
1430                            '#',';', '%', '\0'
1431                    };
1432            const char *cmtchar = comments;
1433            int iscomment = 0;
1434    
1435            if (string == NULL) return(1);
1436    
1437            string = skipspaces(string);
1438    
1439            while(*cmtchar != '\0') {
1440                    if(*string == *cmtchar) {
1441                            iscomment = 1;
1442                            break;
1443                    }
1444                    cmtchar++;
1445            }
1446    
1447            return(iscomment);
1448    }
1449    
1450    #if 0
1451    static void
1452    stats_print(rc_2pass2_t * rc)
1453    {
1454            int i;
1455            const char frame_type[4] = { 'i', 'p', 'b', 's'};
1456    
1457            for (i=0; i<rc->num_frames; i++) {
1458                    twopass_stat_t *s = &rc->stats[i];
1459                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- frame:%d type:%c quant:%d stats:%d scaled:%d desired:%d actual:%d overflow(%c):%.2f\n",
1460                                    i, frame_type[s->type-1], -1, s->length, s->scaled_length,
1461                                    s->desired_length, -1, frame_type[s->type-1], -1.0f);
1462            }
1463    }
1464    #endif
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