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revision 1.1, Tue Mar 25 10:58:33 2003 UTC revision 1.1.2.33, Sun Dec 21 17:38:17 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    #define BQUANT_PRESCALE
33    #undef COMPENSATE_FORMULA
34    
35    /* forces second pass not to be bigger than first */
36    #undef PASS_SMALLER
37    
38    #include <stdio.h>
39    #include <math.h>
40    #include <limits.h>
41    
42    #include "../xvid.h"
43    #include "../image/image.h"
44    
45    /*****************************************************************************
46     * Some default settings
47     ****************************************************************************/
48    
49    #define DEFAULT_KEYFRAME_BOOST 0
50    #define DEFAULT_OVERFLOW_CONTROL_STRENGTH 10
51    #define DEFAULT_CURVE_COMPRESSION_HIGH 0
52    #define DEFAULT_CURVE_COMPRESSION_LOW 0
53    #define DEFAULT_MAX_OVERFLOW_IMPROVEMENT 10
54    #define DEFAULT_MAX_OVERFLOW_DEGRADATION 10
55    
56    /* Keyframe settings */
57    #define DEFAULT_KFREDUCTION 20
58    #define DEFAULT_KFTHRESHOLD 1
59    
60    /*****************************************************************************
61     * Some default constants (can be tuned)
62     ****************************************************************************/
63    
64    /* Specify the invariant part of the headers bits (header+MV)
65     * as  hlength/cst */
66    #define INVARIANT_HEADER_PART_IVOP 1 /* factor 1.0f   */
67    #define INVARIANT_HEADER_PART_PVOP 2 /* factor 0.5f   */
68    #define INVARIANT_HEADER_PART_BVOP 8 /* factor 0.125f */
69    
70    /*****************************************************************************
71     * Structures
72     ****************************************************************************/
73    
74    /* Statistics */
75    typedef struct {
76            int type;               /* first pass type */
77            int quant;              /* first pass quant */
78            int blks[3];            /* k,m,y blks */
79            int length;             /* first pass length */
80            int invariant;          /* what we assume as being invariant between the two passes, it's a sub part of header + MV bits */
81            int scaled_length;      /* scaled length */
82            int desired_length;     /* desired length; calculated during encoding */
83            int error;
84    
85            int zone_mode;   /* XVID_ZONE_xxx */
86            double weight;
87    } twopass_stat_t;
88    
89    /* Context struct */
90    typedef struct
91    {
92            xvid_plugin_2pass2_t param;
93    
94            /*----------------------------------
95             * constant statistical data
96             *--------------------------------*/
97    
98            /* Number of frames of the sequence */
99            int num_frames;
100    
101            /* Number of Intra frames of the sequence */
102            int num_keyframes;
103    
104            /* Target filesize to reach */
105            uint64_t target;
106    
107            /* Count of each frame types */
108            int count[3];
109    
110            /* Total length of each frame types (1st pass) */
111            uint64_t tot_length[3];
112            uint64_t tot_invariant[3];
113    
114            /* Average length of each frame types (used first for 1st pass data and
115             * then for scaled averages */
116            double avg_length[3];
117    
118            /* Minimum frame length allowed for each frame type */
119            int min_length[3];
120    
121            /* Total bytes per frame type once the curve has been scaled
122             * NB: advanced parameters do not change this value. This field
123             *     represents the total scaled w/o any advanced settings */
124            uint64_t tot_scaled_length[3];
125    
126            /* Maximum observed frame size observed during the first pass, the RC
127             * will try tp force all frame sizes in the second pass to be under that
128             * limit */
129            int max_length;
130    
131            /*----------------------------------
132             * Zones statistical data
133             *
134             * ToDo: Fix zones, current
135             *       implementation is buggy
136             *--------------------------------*/
137    
138            /* Average weight of the zones */
139            double avg_weight;
140    
141            /* Total length used by XVID_ZONE_QUANT zones */
142            uint64_t tot_quant;
143            uint64_t tot_quant_invariant;
144    
145            /*----------------------------------
146             * Advanced settings helper ratios
147             *--------------------------------*/
148    
149            /* This the ratio that has to be applied to all p/b frames in order
150             * to reserve/retrieve bits for/from keyframe boosting and consecutive
151             * keyframe penalty */
152            double pb_iboost_tax_ratio;
153    
154            /* This the ratio to apply to all b/p frames in order to respect the
155             * assymetric curve compression while respecting a target filesize
156             * NB: The assymetric delta gain has to be computed before this ratio
157             *     is applied, and then the delta is added to the scaled size */
158            double assymetric_tax_ratio;
159    
160            /*----------------------------------
161             * Data from the stats file kept
162             * into RAM for easy access
163             *--------------------------------*/
164    
165            /* Array of keyframe locations
166             * eg: rc->keyframe_locations[100] returns the frame number of the 100th
167             *     keyframe */
168            int *keyframe_locations;
169    
170            /* Index of the last keyframe used in the keyframe_location */
171            int KF_idx;
172    
173            /* Array of all 1st pass data file -- see the twopass_stat_t structure
174             * definition for more details */
175            twopass_stat_t * stats;
176    
177            /*----------------------------------
178             * Histerysis helpers
179             *--------------------------------*/
180    
181            /* This field holds the int2float conversion errors of each quant per
182             * frame type, this allow the RC to keep track of rouding error and thus
183             * increase or decrease the chosen quant according to this residue */
184            double quant_error[3][32];
185    
186            /* This fields stores the count of each quant usage per frame type
187             * No real role but for debugging */
188            int quant_count[3][32];
189    
190            /* Last valid quantizer used per frame type, it allows quantizer
191             * increament/decreament limitation in order to avoid big image quality
192             * "jumps" */
193            int last_quant[3];
194    
195            /*----------------------------------
196             * Overflow control
197             *--------------------------------*/
198    
199            /* Current overflow that has to be distributed to p/b frames */
200            double overflow;
201    
202            /* Total overflow for keyframes -- not distributed directly */
203            double KFoverflow;
204    
205            /* Amount of keyframe overflow to introduce to the global p/b frame
206             * overflow counter at each encoded frame */
207            double KFoverflow_partial;
208    
209            /* Unknown ???
210             * ToDo: description */
211            double fq_error;
212    
213            /*----------------------------------
214             * Debug
215             *--------------------------------*/
216            double desired_total;
217            double real_total;
218    } rc_2pass2_t;
219    
220    
221    /*****************************************************************************
222     * Sub plugin functions prototypes
223     ****************************************************************************/
224    
225    static int rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t ** handle);
226    static int rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data);
227    static int rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data);
228    static int rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy);
229    
230    /*****************************************************************************
231     * Plugin definition
232     ****************************************************************************/
233    
234    int
235    xvid_plugin_2pass2(void * handle, int opt, void * param1, void * param2)
236    {
237            switch(opt) {
238            case XVID_PLG_INFO :
239            case XVID_PLG_FRAME :
240                    return 0;
241    
242            case XVID_PLG_CREATE :
243                    return rc_2pass2_create((xvid_plg_create_t*)param1, param2);
244    
245            case XVID_PLG_DESTROY :
246                    return rc_2pass2_destroy((rc_2pass2_t*)handle, (xvid_plg_destroy_t*)param1);
247    
248            case XVID_PLG_BEFORE :
249                    return rc_2pass2_before((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
250    
251            case XVID_PLG_AFTER :
252                    return rc_2pass2_after((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
253            }
254    
255            return XVID_ERR_FAIL;
256    }
257    
258    /*****************************************************************************
259     * Sub plugin functions definitions
260     ****************************************************************************/
261    
262    /* First a few local helping function prototypes */
263    static  int statsfile_count_frames(rc_2pass2_t * rc, char * filename);
264    static  int statsfile_load(rc_2pass2_t *rc, char * filename);
265    static void zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create);
266    static void first_pass_stats_prepare_data(rc_2pass2_t * rc);
267    static void first_pass_scale_curve_internal(rc_2pass2_t *rc);
268    static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);
269    #if 0
270    static void stats_print(rc_2pass2_t * rc);
271    #endif
272    
273    /*----------------------------------------------------------------------------
274     *--------------------------------------------------------------------------*/
275    
276    static int
277    rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t **handle)
278    {
279            xvid_plugin_2pass2_t * param = (xvid_plugin_2pass2_t *)create->param;
280            rc_2pass2_t * rc;
281            int i;
282    
283            rc = malloc(sizeof(rc_2pass2_t));
284            if (rc == NULL)
285                    return XVID_ERR_MEMORY;
286    
287            rc->param = *param;
288    
289            /* Initialize all defaults */
290    #define _INIT(a, b) if((a) <= 0) (a) = (b)
291            /* Let's set our defaults if needed */
292            _INIT(rc->param.keyframe_boost, DEFAULT_KEYFRAME_BOOST);
293            _INIT(rc->param.overflow_control_strength, DEFAULT_OVERFLOW_CONTROL_STRENGTH);
294            _INIT(rc->param.curve_compression_high, DEFAULT_CURVE_COMPRESSION_HIGH);
295            _INIT(rc->param.curve_compression_low, DEFAULT_CURVE_COMPRESSION_LOW);
296            _INIT(rc->param.max_overflow_improvement, DEFAULT_MAX_OVERFLOW_IMPROVEMENT);
297            _INIT(rc->param.max_overflow_degradation,  DEFAULT_MAX_OVERFLOW_DEGRADATION);
298    
299            /* Keyframe settings */
300            _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);
301            _INIT(rc->param.kfthreshold, DEFAULT_KFTHRESHOLD);
302    #undef _INIT
303    
304            /* Initialize some stuff to zero */
305            for(i=0; i<3; i++) {
306                    int j;
307                    for (j=0; j<32; j++) {
308                            rc->quant_error[i][j] = 0;
309                            rc->quant_count[i][j] = 0;
310                    }
311            }
312    
313            for (i=0; i<3; i++) rc->last_quant[i] = 0;
314    
315            rc->fq_error = 0;
316    
317            /* Count frames (and intra frames) in the stats file, store the result into
318             * the rc structure */
319            if (statsfile_count_frames(rc, param->filename) == -1) {
320                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
321                    free(rc);
322                    return(XVID_ERR_FAIL);
323            }
324    
325            /* Allocate the stats' memory */
326            if ((rc->stats = malloc(rc->num_frames * sizeof(twopass_stat_t))) == NULL) {
327                    free(rc);
328                    return(XVID_ERR_MEMORY);
329            }
330    
331            /* Allocate keyframes location's memory
332             * PS: see comment in pre_process0 for the +1 location requirement */
333            rc->keyframe_locations = malloc((rc->num_keyframes + 1) * sizeof(int));
334            if (rc->keyframe_locations == NULL) {
335                    free(rc->stats);
336                    free(rc);
337                    return(XVID_ERR_MEMORY);
338            }
339    
340            /* Load the first pass stats */
341            if (statsfile_load(rc, param->filename) == -1) {
342                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
343                    free(rc->keyframe_locations);
344                    free(rc->stats);
345                    free(rc);
346                    return XVID_ERR_FAIL;
347            }
348    
349            /* Compute the target filesize */
350            if (rc->param.bitrate<0) {
351                    /* if negative, bitrate equals the target (in kbytes) */
352                    rc->target = ((uint64_t)(-rc->param.bitrate)) * 1024;
353            } else if (rc->num_frames  < create->fbase/create->fincr) {
354                    /* Source sequence is less than 1s long, we do as if it was 1s long */
355                    rc->target = rc->param.bitrate / 8;
356            } else {
357                    /* Target filesize = bitrate/8 * numframes / framerate */
358                    rc->target =
359                            ((uint64_t)rc->param.bitrate * (uint64_t)rc->num_frames * \
360                             (uint64_t)create->fincr) / \
361                            ((uint64_t)create->fbase * 8);
362            }
363    
364            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Frame rate: %d/%d (%ffps)\n",
365                            create->fbase, create->fincr,
366                            (double)create->fbase/(double)create->fincr);
367            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Number of frames: %d\n", rc->num_frames);
368            if(rc->param.bitrate>=0)
369                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target bitrate: %ld\n", rc->param.bitrate);
370            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target filesize: %lld\n", rc->target);
371    
372            /* Compensate the average frame overhead caused by the container */
373            rc->target -= rc->num_frames*rc->param.container_frame_overhead;
374            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Container Frame overhead: %d\n", rc->param.container_frame_overhead);
375            if(rc->param.container_frame_overhead)
376                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- New target filesize after container compensation: %lld\n", rc->target);
377    
378            /* Gathers some information about first pass stats:
379             *  - finds the minimum frame length for each frame type during 1st pass.
380             *     rc->min_size[]
381             *  - determines the maximum frame length observed (no frame type distinction).
382             *     rc->max_size
383             *  - count how many times each frame type has been used.
384             *     rc->count[]
385             *  - total bytes used per frame type
386             *     rc->tot_length[]
387             *  - total bytes considered invariant between the 2 passes
388             *  - store keyframe location
389             *     rc->keyframe_locations[]
390             */
391            first_pass_stats_prepare_data(rc);
392    
393            /* When bitrate is not given it means it has been scaled by an external
394             * application */
395            if (rc->param.bitrate) {
396                    /* Apply zone settings
397                     * - set rc->tot_quant which represents the total num of bytes spent in
398                     *   fixed quant zones
399                     * - set rc->tot_quant_invariant which represents the total num of bytes spent
400                     *   in fixed quant zones for headers */
401                    zone_process(rc, create);
402                    /* Perform internal curve scaling */
403                    first_pass_scale_curve_internal(rc);
404            } else {
405                    /* External scaling -- zones are ignored */
406                    for (i=0;i<rc->num_frames;i++) {
407                            rc->stats[i].zone_mode = XVID_ZONE_WEIGHT;
408                            rc->stats[i].weight = 1.0;
409                    }
410                    rc->avg_weight = 1.0;
411                    rc->tot_quant = 0;
412            }
413    
414            /* Apply advanced curve options, and compute some parameters in order to
415             * shape the curve in the BEFORE/AFTER pair of functions */
416            scaled_curve_apply_advanced_parameters(rc);
417    
418            *handle = rc;
419            return(0);
420    }
421    
422    /*----------------------------------------------------------------------------
423     *--------------------------------------------------------------------------*/
424    
425    static int
426    rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy)
427    {
428            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- target_total:%lld desired_total:%.2f (%.2f%%) actual_total:%.2f (%.2f%%)\n",
429                            rc->target,
430                            rc->desired_total,
431                            100*rc->desired_total/(double)rc->target,
432                            rc->real_total,
433                            100*rc->real_total/(double)rc->target);
434    
435            free(rc->keyframe_locations);
436            free(rc->stats);
437            free(rc);
438            return(0);
439    }
440    
441    /*----------------------------------------------------------------------------
442     *--------------------------------------------------------------------------*/
443    
444    static int
445    rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data)
446    {
447            twopass_stat_t * s = &rc->stats[data->frame_num];
448            double dbytes;
449            double scaled_quant;
450            double overflow;
451            int capped_to_max_framesize = 0;
452    
453            /* This function is quite long but easy to understand. In order to simplify
454             * the code path (a bit), we treat 3 cases that can return immediatly. */
455    
456            /* First case: Another plugin has already set a quantizer */
457            if (data->quant > 0)
458                    return(0);
459    
460            /* Second case: insufficent stats data
461             * We can't guess much what we should do, let core decide all alone */
462            if (data->frame_num >= rc->num_frames) {
463                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- stats file too short (now processing frame %d)",
464                            data->frame_num);
465                    return(0);
466            }
467    
468            /* Third case: We are in a Quant zone
469             * Quant zones must just ensure we use the same settings as first pass
470             * So set the quantizer and the type */
471            if (s->zone_mode == XVID_ZONE_QUANT) {
472                    /* Quant stuff */
473                    rc->fq_error += s->weight;
474                    data->quant = (int)rc->fq_error;
475                    rc->fq_error -= data->quant;
476    
477                    /* The type stuff */
478                    data->type = s->type;
479    
480                    /* The only required data for AFTER step is this one for the overflow
481                     * control */
482                    s->desired_length = s->length;
483    
484                    return(0);
485            }
486    
487    
488            /*************************************************************************/
489            /*************************************************************************/
490            /*************************************************************************/
491    
492            /*-------------------------------------------------------------------------
493             * Frame bit allocation first part
494             *
495             * First steps apply user settings, just like it is done in the theoritical
496             * scaled_curve_apply_advanced_parameters
497             *-----------------------------------------------------------------------*/
498    
499            /* Set desired to what we are wanting to obtain for this frame */
500            dbytes = (double)s->scaled_length;
501    
502            /* IFrame user settings*/
503            if (s->type == XVID_TYPE_IVOP) {
504                    /* Keyframe boosting -- All keyframes benefit from it */
505                    dbytes += dbytes*rc->param.keyframe_boost / 100;
506    
507    #if 0 /* ToDo: decide how to apply kfthresholding */
508    #endif
509            } else {
510    
511                    /* P/S/B frames must reserve some bits for iframe boosting */
512                    dbytes *= rc->pb_iboost_tax_ratio;
513    
514                    /* Apply assymetric curve compression */
515                    if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
516                            double assymetric_delta;
517    
518                            /* Compute the assymetric delta, this is computed before applying
519                             * the tax, as done in the pre_process function */
520                            if (dbytes > rc->avg_length[s->type-1])
521                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_high / 100.0;
522                            else
523                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_low  / 100.0;
524    
525                            /* Now we must apply the assymetric tax, else our curve compression
526                             * would not give a theoritical target size equal to what it is
527                             * expected */
528                            dbytes *= rc->assymetric_tax_ratio;
529    
530                            /* Now we can add the assymetric delta */
531                            dbytes += assymetric_delta;
532                    }
533            }
534    
535            /* That is what we would like to have -- Don't put that chunk after
536             * overflow control, otherwise, overflow is counted twice and you obtain
537             * half sized bitrate sequences */
538            s->desired_length  = (int)dbytes;
539            rc->desired_total += dbytes;
540    
541            /*------------------------------------------------------------------------
542             * Frame bit allocation: overflow control part.
543             *
544             * Unlike the theoritical scaled_curve_apply_advanced_parameters, here
545             * it's real encoding and we need to make sure we don't go so far from
546             * what is our ideal scaled curve.
547             *-----------------------------------------------------------------------*/
548    
549            /* Compute the overflow we should compensate */
550            if (s->type != XVID_TYPE_IVOP || rc->overflow > 0) {
551                    double frametype_factor;
552                    double framesize_factor;
553    
554                    /* Take only the desired part of overflow */
555                    overflow = rc->overflow;
556    
557                    /* Factor that will take care to decrease the overflow applied
558                     * according to the importance of this frame type in term of
559                     * overall size */
560                    frametype_factor  = rc->count[XVID_TYPE_IVOP-1]*rc->avg_length[XVID_TYPE_IVOP-1];
561                    frametype_factor += rc->count[XVID_TYPE_PVOP-1]*rc->avg_length[XVID_TYPE_PVOP-1];
562                    frametype_factor += rc->count[XVID_TYPE_BVOP-1]*rc->avg_length[XVID_TYPE_BVOP-1];
563                    frametype_factor /= rc->count[s->type-1]*rc->avg_length[s->type-1];
564                    frametype_factor  = 1/frametype_factor;
565    
566                    /* Factor that will take care not to compensate too much for this frame
567                     * size */
568                    framesize_factor  = dbytes;
569                    framesize_factor /= rc->avg_length[s->type-1];
570    
571                    /* Treat only the overflow part concerned by this frame type and size */
572                    overflow *= frametype_factor;
573    #if 0
574                    /* Leave this one alone, as it impacts badly on quality */
575                    overflow *= framesize_factor;
576    #endif
577    
578                    /* Apply the overflow strength imposed by the user */
579                    overflow *= (rc->param.overflow_control_strength/100.0f);
580            } else {
581                    /* no negative overflow applied in IFrames because:
582                     *  - their role is important as they're references for P/BFrames.
583                     *  - there aren't much in typical sequences, so if an IFrame overflows too
584                     *    much, this overflow may impact the next IFrame too much and generate
585                     *    a sequence of poor quality frames */
586                    overflow = 0;
587            }
588    
589            /* Make sure we are not trying to compensate more overflow than we even have */
590            if (fabs(overflow) > fabs(rc->overflow))
591                    overflow = rc->overflow;
592    
593            /* Make sure the overflow doesn't make the frame size to get out of the range
594             * [-max_degradation..+max_improvment] */
595            if (overflow > dbytes*rc->param.max_overflow_improvement / 100) {
596                    if(overflow <= dbytes)
597                            dbytes += dbytes * rc->param.max_overflow_improvement / 100;
598                    else
599                            dbytes += overflow * rc->param.max_overflow_improvement / 100;
600            } else if (overflow < - dbytes * rc->param.max_overflow_degradation / 100) {
601                    dbytes -= dbytes * rc->param.max_overflow_degradation / 100;
602            } else {
603                    dbytes += overflow;
604            }
605    
606            /*-------------------------------------------------------------------------
607             * Frame bit allocation last part:
608             *
609             * Cap frame length so we don't reach neither bigger frame sizes than first
610             * pass nor smaller than the allowed minimum.
611             *-----------------------------------------------------------------------*/
612    
613    #ifdef PASS_SMALLER
614            if (dbytes > s->length) {
615                    dbytes = s->length;
616            } else
617    #endif
618                    if (dbytes < rc->min_length[s->type-1]) {
619                    dbytes = rc->min_length[s->type-1];
620            } else if (dbytes > rc->max_length) {
621                    /* ToDo: this condition is always wrong as max_length == maximum frame
622                     * length of first pass, so the first condition already caps the frame
623                     * size... */
624                    capped_to_max_framesize = 1;
625                    dbytes = rc->max_length;
626                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- frame:%d Capped to maximum frame size\n",
627                                    data->frame_num);
628            }
629    
630            /*------------------------------------------------------------------------
631             * Desired frame length <-> quantizer mapping
632             *-----------------------------------------------------------------------*/
633    
634    #ifdef BQUANT_PRESCALE
635            /* For bframes we prescale the quantizer to avoid too high quant scaling */
636            if(s->type == XVID_TYPE_BVOP) {
637    
638                    twopass_stat_t *b_ref = s;
639    
640                    /* Find the reference frame */
641                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
642                            b_ref--;
643    
644                    /* Compute the original quant */
645                    s->quant  = 2*(100*s->quant - data->bquant_offset);
646                    s->quant += data->bquant_ratio - 1; /* to avoid rounding issues */
647                    s->quant  = s->quant/data->bquant_ratio - b_ref->quant;
648            }
649    #endif
650    
651            /* Don't laugh at this very 'simple' quant<->size relationship, it
652             * proves to be acurate enough for our algorithm */
653            scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;
654    
655    #ifdef COMPENSATE_FORMULA
656            /* We know xvidcore will apply the bframe formula again, so we compensate
657             * it right now to make sure we would not apply it twice */
658            if(s->type == XVID_TYPE_BVOP) {
659    
660                    twopass_stat_t *b_ref = s;
661    
662                    /* Find the reference frame */
663                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
664                            b_ref--;
665    
666                    /* Compute the quant it would be if the core did not apply the bframe
667                     * formula */
668                    scaled_quant  = 100*scaled_quant - data->bquant_offset;
669                    scaled_quant += data->bquant_ratio - 1; /* to avoid rouding issues */
670                    scaled_quant /= data->bquant_ratio;
671            }
672    #endif
673    
674            /* Quantizer has been scaled using floating point operations/results, we
675             * must cast it to integer */
676            data->quant = (int)scaled_quant;
677    
678            /* Let's clip the computed quantizer, if needed */
679            if (data->quant < 1) {
680                    data->quant = 1;
681            } else if (data->quant > 31) {
682                    data->quant = 31;
683            } else {
684    
685                    /* The frame quantizer has not been clipped, this appears to be a good
686                     * computed quantizer, do not loose quantizer decimal part that we
687                     * accumulate for later reuse when its sum represents a complete
688                     * unit. */
689                    rc->quant_error[s->type-1][data->quant] += scaled_quant - (double)data->quant;
690    
691                    if (rc->quant_error[s->type-1][data->quant] >= 1.0) {
692                            rc->quant_error[s->type-1][data->quant] -= 1.0;
693                            data->quant++;
694                    } else if (rc->quant_error[s->type-1][data->quant] <= -1.0) {
695                            rc->quant_error[s->type-1][data->quant] += 1.0;
696                            data->quant--;
697                    }
698            }
699    
700            /* Now we have a computed quant that is in the right quante range, with a
701             * possible +1 correction due to cumulated error. We can now safely clip
702             * the quantizer again with user's quant ranges. "Safely" means the Rate
703             * Control could learn more about this quantizer, this knowledge is useful
704             * for future frames even if it this quantizer won't be really used atm,
705             * that's why we don't perform this clipping earlier. */
706            if (data->quant < data->min_quant[s->type-1]) {
707                    data->quant = data->min_quant[s->type-1];
708            } else if (data->quant > data->max_quant[s->type-1]) {
709                    data->quant = data->max_quant[s->type-1];
710            }
711    
712            /* To avoid big quality jumps from frame to frame, we apply a "security"
713             * rule that makes |last_quant - new_quant| <= 2. This rule only applies
714             * to predicted frames (P and B) */
715            if (s->type != XVID_TYPE_IVOP && rc->last_quant[s->type-1] && capped_to_max_framesize == 0) {
716    
717                    if (data->quant > rc->last_quant[s->type-1] + 2) {
718                            data->quant = rc->last_quant[s->type-1] + 2;
719                            DPRINTF(XVID_DEBUG_RC,
720                                            "[xvid rc] -- frame %d p/b-frame quantizer prevented from rising too steeply\n",
721                                            data->frame_num);
722                    }
723                    if (data->quant < rc->last_quant[s->type-1] - 2) {
724                            data->quant = rc->last_quant[s->type-1] - 2;
725                            DPRINTF(XVID_DEBUG_RC,
726                                            "[xvid rc] -- frame:%d p/b-frame quantizer prevented from falling too steeply\n",
727                                            data->frame_num);
728                    }
729            }
730    
731            /* We don't want to pollute the RC histerisis when our computed quant has
732             * been computed from a capped frame size */
733            if (capped_to_max_framesize == 0)
734                    rc->last_quant[s->type-1] = data->quant;
735    
736            /* Don't forget to force 1st pass frame type ;-) */
737            data->type = s->type;
738    
739            return 0;
740    }
741    
742    /*----------------------------------------------------------------------------
743     *--------------------------------------------------------------------------*/
744    
745    static int
746    rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data)
747    {
748            const char frame_type[4] = { 'i', 'p', 'b', 's'};
749            twopass_stat_t * s = &rc->stats[data->frame_num];
750    
751            /* Insufficent stats data */
752            if (data->frame_num >= rc->num_frames)
753                    return 0;
754    
755            /* Update the quantizer counter */
756            rc->quant_count[s->type-1][data->quant]++;
757    
758            /* Update the frame type overflow */
759            if (data->type == XVID_TYPE_IVOP) {
760                    int kfdiff = 0;
761    
762                    if(rc->KF_idx != rc->num_frames -1) {
763                            kfdiff  = rc->keyframe_locations[rc->KF_idx+1];
764                            kfdiff -= rc->keyframe_locations[rc->KF_idx];
765                    }
766    
767                    /* Flush Keyframe overflow accumulator */
768                    rc->overflow += rc->KFoverflow;
769    
770                    /* Store the frame overflow to the keyframe accumulator */
771                    rc->KFoverflow = s->desired_length - data->length;
772    
773                    if (kfdiff > 1) {
774                            /* Non-consecutive keyframes case:
775                             * We can then divide this total keyframe overflow into equal parts
776                             * that we will distribute into regular overflow at each frame
777                             * between the sequence bounded by two IFrames */
778                            rc->KFoverflow_partial = rc->KFoverflow / (kfdiff - 1);
779                    } else {
780                            /* Consecutive keyframes case:
781                             * Flush immediatly the keyframe overflow and reset keyframe
782                             * overflow */
783                            rc->overflow += rc->KFoverflow;
784                            rc->KFoverflow = 0;
785                            rc->KFoverflow_partial = 0;
786                    }
787                    rc->KF_idx++;
788            } else {
789                    /* Accumulate the frame overflow */
790                    rc->overflow += s->desired_length - data->length;
791    
792                    /* Distribute part of the keyframe overflow */
793                    rc->overflow += rc->KFoverflow_partial;
794    
795                    /* Don't forget to substract that same amount from the total keyframe
796                     * overflow */
797                    rc->KFoverflow -= rc->KFoverflow_partial;
798            }
799    
800            rc->overflow += (s->error = s->desired_length - data->length);
801            rc->real_total += data->length;
802    
803            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",
804                            data->frame_num,
805                            frame_type[data->type-1],
806                            data->quant,
807                            s->length,
808                            s->scaled_length,
809                            s->desired_length,
810                            s->desired_length - s->error,
811                            -s->error,
812                            rc->overflow);
813    
814            return(0);
815    }
816    
817    /*****************************************************************************
818     * Helper functions definition
819     ****************************************************************************/
820    
821    /* Default buffer size for reading lines */
822    #define BUF_SZ   1024
823    
824    /* Helper functions for reading/parsing the stats file */
825    static char *skipspaces(char *string);
826    static int iscomment(char *string);
827    static char *readline(FILE *f);
828    
829    /* This function counts the number of frame entries in the stats file
830     * It also counts the number of I Frames */
831    static int
832    statsfile_count_frames(rc_2pass2_t * rc, char * filename)
833    {
834            FILE * f;
835            char *line;
836            int lines;
837    
838            rc->num_frames = 0;
839            rc->num_keyframes = 0;
840    
841            if ((f = fopen(filename, "rb")) == NULL)
842                    return(-1);
843    
844            lines = 0;
845            while ((line = readline(f)) != NULL) {
846    
847                    char *ptr;
848                    char type;
849                    int fields;
850    
851                    lines++;
852    
853                    /* We skip spaces */
854                    ptr = skipspaces(line);
855    
856                    /* Skip coment lines or empty lines */
857                    if(iscomment(ptr) || *ptr == '\0') {
858                            free(line);
859                            continue;
860                    }
861    
862                    /* Read the stat line from buffer */
863                    fields = sscanf(ptr, "%c", &type);
864    
865                    /* Valid stats files have at least 7 fields */
866                    if (fields == 1) {
867                            switch(type) {
868                            case 'i':
869                            case 'I':
870                                    rc->num_keyframes++;
871                            case 'p':
872                            case 'P':
873                            case 'b':
874                            case 'B':
875                            case 's':
876                            case 'S':
877                                    rc->num_frames++;
878                                    break;
879                            default:
880                                    DPRINTF(XVID_DEBUG_RC,
881                                                    "[xvid rc] -- WARNING: L%d unknown frame type used (%c).\n",
882                                                    lines, type);
883                            }
884                    } else {
885                                    DPRINTF(XVID_DEBUG_RC,
886                                                    "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",
887                                                    lines, 7-fields);
888                    }
889    
890                    /* Free the line buffer */
891                    free(line);
892            }
893    
894            /* We are done with the file */
895            fclose(f);
896    
897            return(0);
898    }
899    
900    /* open stats file(s) and read into rc->stats array */
901    static int
902    statsfile_load(rc_2pass2_t *rc, char * filename)
903    {
904            FILE * f;
905            int processed_entries;
906    
907            /* Opens the file */
908            if ((f = fopen(filename, "rb"))==NULL)
909                    return(-1);
910    
911            processed_entries = 0;
912            while(processed_entries < rc->num_frames) {
913                    char type;
914                    int fields;
915                    twopass_stat_t * s = &rc->stats[processed_entries];
916                    char *line, *ptr;
917    
918                    /* Read the line from the file */
919                    if((line = readline(f)) == NULL)
920                            break;
921    
922                    /* We skip spaces */
923                    ptr = skipspaces(line);
924    
925                    /* Skip comment lines or empty lines */
926                    if(iscomment(ptr) || *ptr == '\0') {
927                            free(line);
928                            continue;
929                    }
930    
931                    /* Reset this field that is optional */
932                    s->scaled_length = 0;
933    
934                    /* Convert the fields */
935                    fields = sscanf(ptr,
936                                                    "%c %d %d %d %d %d %d %d\n",
937                                                    &type,
938                                                    &s->quant,
939                                                    &s->blks[0], &s->blks[1], &s->blks[2],
940                                                    &s->length, &s->invariant /* not really yet */,
941                                                    &s->scaled_length);
942    
943                    /* Free line buffer, we don't need it anymore */
944                    free(line);
945    
946                    /* Fail silently, this has probably been warned in
947                     * statsfile_count_frames */
948                    if(fields != 7 && fields != 8)
949                            continue;
950    
951                    /* Convert frame type and compute the invariant length part */
952                    switch(type) {
953                    case 'i':
954                    case 'I':
955                            s->type = XVID_TYPE_IVOP;
956                            s->invariant /= INVARIANT_HEADER_PART_IVOP;
957                            break;
958                    case 'p':
959                    case 'P':
960                    case 's':
961                    case 'S':
962                            s->type = XVID_TYPE_PVOP;
963                            s->invariant /= INVARIANT_HEADER_PART_PVOP;
964                            break;
965                    case 'b':
966                    case 'B':
967                            s->type = XVID_TYPE_BVOP;
968                            s->invariant /= INVARIANT_HEADER_PART_BVOP;
969                            break;
970                    default:
971                            /* Same as before, fail silently */
972                            continue;
973                    }
974    
975                    /* Ok it seems it's been processed correctly */
976                    processed_entries++;
977            }
978    
979            /* Close the file */
980            fclose(f);
981    
982            return(0);
983    }
984    
985    /* pre-process the statistics data
986     * - for each type, count, tot_length, min_length, max_length
987     * - set keyframes_locations */
988    static void
989    first_pass_stats_prepare_data(rc_2pass2_t * rc)
990    {
991            int i,j;
992    
993            /* *rc fields initialization
994             * NB: INT_MAX and INT_MIN are used in order to be immediately replaced
995             *     with real values of the 1pass */
996            for (i=0; i<3; i++) {
997                    rc->count[i]=0;
998                    rc->tot_length[i] = 0;
999                    rc->tot_invariant[i] = 0;
1000                    rc->min_length[i] = INT_MAX;
1001            }
1002    
1003            rc->max_length = INT_MIN;
1004    
1005            /* Loop through all frames and find/compute all the stuff this function
1006             * is supposed to do */
1007            for (i=j=0; i<rc->num_frames; i++) {
1008                    twopass_stat_t * s = &rc->stats[i];
1009    
1010                    rc->count[s->type-1]++;
1011                    rc->tot_length[s->type-1] += s->length;
1012                    rc->tot_invariant[s->type-1] += s->invariant;
1013    
1014                    if (s->length < rc->min_length[s->type-1]) {
1015                            rc->min_length[s->type-1] = s->length;
1016                    }
1017    
1018                    if (s->length > rc->max_length) {
1019                            rc->max_length = s->length;
1020                    }
1021    
1022                    if (s->type == XVID_TYPE_IVOP) {
1023                            rc->keyframe_locations[j] = i;
1024                            j++;
1025                    }
1026            }
1027    
1028            /* NB:
1029             * The "per sequence" overflow system considers a natural sequence to be
1030             * formed by all frames between two iframes, so if we want to make sure
1031             * the system does not go nuts during last sequence, we force the last
1032             * frame to appear in the keyframe locations array. */
1033            rc->keyframe_locations[j] = i;
1034    
1035            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass IFrame length: %d\n", rc->min_length[0]);
1036            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass PFrame length: %d\n", rc->min_length[1]);
1037            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass BFrame length: %d\n", rc->min_length[2]);
1038    }
1039    
1040    /* calculate zone weight "center" */
1041    static void
1042    zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create)
1043    {
1044            int i,j;
1045            int n = 0;
1046    
1047            rc->avg_weight = 0.0;
1048            rc->tot_quant = 0;
1049            rc->tot_quant_invariant = 0;
1050    
1051            if (create->num_zones == 0) {
1052                    for (j = 0; j < rc->num_frames; j++) {
1053                            rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1054                            rc->stats[j].weight = 1.0;
1055                    }
1056                    rc->avg_weight += rc->num_frames * 1.0;
1057                    n += rc->num_frames;
1058            }
1059    
1060    
1061            for(i=0; i < create->num_zones; i++) {
1062    
1063                    int next = (i+1<create->num_zones) ? create->zones[i+1].frame : rc->num_frames;
1064    
1065                    if (i==0 && create->zones[i].frame > 0) {
1066                            for (j = 0; j < create->zones[i].frame && j < rc->num_frames; j++) {
1067                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1068                                    rc->stats[j].weight = 1.0;
1069                            }
1070                            rc->avg_weight += create->zones[i].frame * 1.0;
1071                            n += create->zones[i].frame;
1072                    }
1073    
1074                    if (create->zones[i].mode == XVID_ZONE_WEIGHT) {
1075                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1076                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1077                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1078                            }
1079                            next -= create->zones[i].frame;
1080                            rc->avg_weight += (double)(next * create->zones[i].increment) / (double)create->zones[i].base;
1081                            n += next;
1082                    } else{  /* XVID_ZONE_QUANT */
1083                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1084                                    rc->stats[j].zone_mode = XVID_ZONE_QUANT;
1085                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1086                                    rc->tot_quant += rc->stats[j].length;
1087                                    rc->tot_quant_invariant += rc->stats[j].invariant;
1088                            }
1089                    }
1090            }
1091            rc->avg_weight = n>0 ? rc->avg_weight/n : 1.0;
1092    
1093            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- center_weight:%f (for %d frames)  fixed_bytes:%d\n", rc->avg_weight, n, rc->tot_quant);
1094    }
1095    
1096    
1097    /* scale the curve */
1098    static void
1099    first_pass_scale_curve_internal(rc_2pass2_t *rc)
1100    {
1101            int64_t target;
1102            int64_t pass1_length;
1103            int64_t total_invariant;
1104            double scaler;
1105            int i, num_MBs;
1106    
1107            /* We only scale texture data ! */
1108            total_invariant  = rc->tot_invariant[XVID_TYPE_IVOP-1];
1109            total_invariant += rc->tot_invariant[XVID_TYPE_PVOP-1];
1110            total_invariant += rc->tot_invariant[XVID_TYPE_BVOP-1];
1111            /* don't forget to substract header bytes used in quant zones, otherwise we
1112             * counting them twice */
1113            total_invariant -= rc->tot_quant_invariant;
1114    
1115            /* We remove the bytes used by the fixed quantizer zones during first pass
1116             * with the same quants, so we know very precisely how much that
1117             * represents */
1118            target  = rc->target;
1119            target -= rc->tot_quant;
1120    
1121            /* Do the same for the first pass data */
1122            pass1_length  = rc->tot_length[XVID_TYPE_IVOP-1];
1123            pass1_length += rc->tot_length[XVID_TYPE_PVOP-1];
1124            pass1_length += rc->tot_length[XVID_TYPE_BVOP-1];
1125            pass1_length -= rc->tot_quant;
1126    
1127            /* Let's compute a linear scaler in order to perform curve scaling */
1128            scaler = (double)(target - total_invariant) / (double)(pass1_length - total_invariant);
1129    
1130    #ifdef PASS_SMALLER
1131            if ((target - total_invariant) <= 0 ||
1132                    (pass1_length - total_invariant) <= 0 ||
1133                    target >= pass1_length) {
1134                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected before correction\n");
1135                    scaler = 1.0;
1136            }
1137    #endif
1138    
1139            /* Compute min frame lengths (for each frame type) according to the number
1140             * of MBs. We sum all block type counters of frame 0, this gives us the
1141             * number of MBs.
1142             *
1143             * We compare these hardcoded values with observed values in first pass
1144             * (determined in pre_process0).Then we keep the real minimum. */
1145    
1146            /* Number of MBs */
1147            num_MBs  = rc->stats[0].blks[0];
1148            num_MBs += rc->stats[0].blks[1];
1149            num_MBs += rc->stats[0].blks[2];
1150    
1151            /* Minimum for I frames */
1152            if(rc->min_length[XVID_TYPE_IVOP-1] > ((num_MBs*22) + 240) / 8)
1153                    rc->min_length[XVID_TYPE_IVOP-1] = ((num_MBs*22) + 240) / 8;
1154    
1155            /* Minimum for P/S frames */
1156            if(rc->min_length[XVID_TYPE_PVOP-1] > ((num_MBs) + 88)  / 8)
1157                    rc->min_length[XVID_TYPE_PVOP-1] = ((num_MBs) + 88)  / 8;
1158    
1159            /* Minimum for B frames */
1160            if(rc->min_length[XVID_TYPE_BVOP-1] > 8)
1161                    rc->min_length[XVID_TYPE_BVOP-1] = 8;
1162    
1163            /* Perform an initial scale pass.
1164             *
1165             * If a frame size is scaled underneath our hardcoded minimums, then we
1166             * force the frame size to the minimum, and deduct the original & scaled
1167             * frame length from the original and target total lengths */
1168            for (i=0; i<rc->num_frames; i++) {
1169                    twopass_stat_t * s = &rc->stats[i];
1170                    int len;
1171    
1172                    /* No need to scale frame length for which a specific quantizer is
1173                     * specified thanks to zones */
1174                    if (s->zone_mode == XVID_ZONE_QUANT) {
1175                            s->scaled_length = s->length;
1176                            continue;
1177                    }
1178    
1179                    /* Compute the scaled length -- only non invariant data length is scaled */
1180                    len = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight / rc->avg_weight);
1181    
1182                    /* Compare with the computed minimum */
1183                    if (len < rc->min_length[s->type-1]) {
1184                            /* This is a 'forced size' frame, set its frame size to the
1185                             * computed minimum */
1186                            s->scaled_length = rc->min_length[s->type-1];
1187    
1188                            /* Remove both scaled and original size from their respective
1189                             * total counters, as we prepare a second pass for 'regular'
1190                             * frames */
1191                            target -= s->scaled_length;
1192                            pass1_length -= s->length;
1193                    } else {
1194                            /* Do nothing for now, we'll scale this later */
1195                            s->scaled_length = 0;
1196                    }
1197            }
1198    
1199            /* The first pass on data substracted all 'forced size' frames from the
1200             * total counters. Now, it's possible to scale the 'regular' frames. */
1201    
1202            /* Scaling factor for 'regular' frames */
1203            scaler = (double)(target - total_invariant) / (double)(pass1_length - total_invariant);
1204    
1205    #ifdef PASS_SMALLER
1206            /* Detect undersizing */
1207            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1208                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected after correction\n");
1209                    scaler = 1.0;
1210            }
1211    #endif
1212    
1213            /* Do another pass with the new scaler */
1214            for (i=0; i<rc->num_frames; i++) {
1215                    twopass_stat_t * s = &rc->stats[i];
1216    
1217                    /* Ignore frame with forced frame sizes */
1218                    if (s->scaled_length == 0)
1219                            s->scaled_length = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight / rc->avg_weight);
1220            }
1221    
1222            /* Job done */
1223            return;
1224    }
1225    
1226    /* Apply all user settings to the scaled curve
1227     * This implies:
1228     *   keyframe boosting
1229     *   high/low compression */
1230    static void
1231    scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)
1232    {
1233            int i;
1234            int64_t ivop_boost_total;
1235    
1236            /* Reset the rate controller (per frame type) total byte counters */
1237            for (i=0; i<3; i++) rc->tot_scaled_length[i] = 0;
1238    
1239            /* Compute total bytes for each frame type */
1240            for (i=0; i<rc->num_frames;i++) {
1241                    twopass_stat_t *s = &rc->stats[i];
1242                    rc->tot_scaled_length[s->type-1] += s->scaled_length;
1243            }
1244    
1245            /* First we compute the total amount of bits needed, as being described by
1246             * the scaled distribution. During this pass over the complete stats data,
1247             * we see how much bits two user settings will get/give from/to p&b frames:
1248             *  - keyframe boosting
1249             *  - keyframe distance penalty */
1250            rc->KF_idx = 0;
1251            ivop_boost_total = 0;
1252            for (i=0; i<rc->num_frames; i++) {
1253                    twopass_stat_t * s = &rc->stats[i];
1254    
1255                    /* Some more work is needed for I frames */
1256                    if (s->type == XVID_TYPE_IVOP) {
1257                            int ivop_boost;
1258    
1259                            /* Accumulate bytes needed for keyframe boosting */
1260                            ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;
1261    
1262    #if 0 /* ToDo: decide how to apply kfthresholding */
1263    #endif
1264                            /* If the frame size drops under the minimum length, then cap ivop_boost */
1265                            if (ivop_boost + s->scaled_length < rc->min_length[XVID_TYPE_IVOP-1])
1266                                    ivop_boost = rc->min_length[XVID_TYPE_IVOP-1] - s->scaled_length;
1267    
1268                            /* Accumulate the ivop boost */
1269                            ivop_boost_total += ivop_boost;
1270    
1271                            /* Don't forget to update the keyframe index */
1272                            rc->KF_idx++;
1273                    }
1274            }
1275    
1276            /* Initialize the IBoost tax ratio for P/S/B frames
1277             *
1278             * This ratio has to be applied to p/b/s frames in order to reserve
1279             * additional bits for keyframes (keyframe boosting) or if too much
1280             * keyframe distance is applied, bits retrieved from the keyframes.
1281             *
1282             * ie pb_length *= rc->pb_iboost_tax_ratio;
1283             *
1284             *    gives the ideal length of a p/b frame */
1285    
1286            /* Compute the total length of p/b/s frames (temporary storage into
1287             * movie_curve) */
1288            rc->pb_iboost_tax_ratio  = (double)rc->tot_scaled_length[XVID_TYPE_PVOP-1];
1289            rc->pb_iboost_tax_ratio += (double)rc->tot_scaled_length[XVID_TYPE_BVOP-1];
1290    
1291            /* Compute the ratio described above
1292             *     taxed_total = sum(0, n, tax*scaled_length)
1293             * <=> taxed_total = tax.sum(0, n, scaled_length)
1294             * <=> tax = taxed_total / original_total */
1295            rc->pb_iboost_tax_ratio =
1296                    (rc->pb_iboost_tax_ratio - ivop_boost_total) /
1297                    rc->pb_iboost_tax_ratio;
1298    
1299            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- IFrame boost tax ratio:%.2f\n",
1300                            rc->pb_iboost_tax_ratio);
1301    
1302            /* Compute the average size of frames per frame type */
1303            for(i=0; i<3; i++) {
1304                    /* Special case for missing type or weird case */
1305                    if (rc->count[i] == 0 || rc->pb_iboost_tax_ratio == 0) {
1306                            rc->avg_length[i] = 1;
1307                    } else {
1308                            rc->avg_length[i] = rc->tot_scaled_length[i];
1309    
1310                            if (i == (XVID_TYPE_IVOP-1)) {
1311                                    /* I Frames total has to be added the boost total */
1312                                    rc->avg_length[i] += ivop_boost_total;
1313                            } else {
1314                                    /* P/B frames has to taxed */
1315                                    rc->avg_length[i] *= rc->pb_iboost_tax_ratio;
1316                            }
1317    
1318                            /* Finally compute the average frame size */
1319                            rc->avg_length[i] /= (double)rc->count[i];
1320                    }
1321            }
1322    
1323            /* Assymetric curve compression */
1324            if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
1325                    double symetric_total;
1326                    double assymetric_delta_total;
1327    
1328                    /* Like I frame boosting, assymetric curve compression modifies the total
1329                     * amount of needed bits, we must compute the ratio so we can prescale
1330                     lengths */
1331                    symetric_total = 0;
1332                    assymetric_delta_total = 0;
1333                    for (i=0; i<rc->num_frames; i++) {
1334                            double assymetric_delta;
1335                            double dbytes;
1336                            twopass_stat_t * s = &rc->stats[i];
1337    
1338                            /* I Frames are not concerned by assymetric scaling */
1339                            if (s->type == XVID_TYPE_IVOP)
1340                                    continue;
1341    
1342                            /* During the real run, we would have to apply the iboost tax */
1343                            dbytes = s->scaled_length * rc->pb_iboost_tax_ratio;
1344    
1345                            /* Update the symmetric curve compression total */
1346                            symetric_total += dbytes;
1347    
1348                            /* Apply assymetric curve compression */
1349                            if (dbytes > rc->avg_length[s->type-1])
1350                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_high / 100.0f;
1351                            else
1352                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_low  / 100.0f;
1353    
1354                            /* Cap to the minimum frame size if needed */
1355                            if (dbytes + assymetric_delta < rc->min_length[s->type-1])
1356                                    assymetric_delta = rc->min_length[s->type-1] - dbytes;
1357    
1358                            /* Accumulate after assymetric curve compression */
1359                            assymetric_delta_total += assymetric_delta;
1360                    }
1361    
1362                    /* Compute the tax that all p/b frames have to pay in order to respect the
1363                     * bit distribution changes that the assymetric compression curve imposes
1364                     * We want assymetric_total = sum(0, n-1, tax.scaled_length)
1365                     *      ie assymetric_total = ratio.sum(0, n-1, scaled_length)
1366                     *         ratio = assymetric_total / symmetric_total */
1367                    rc->assymetric_tax_ratio = ((double)symetric_total - (double)assymetric_delta_total) / (double)symetric_total;
1368            } else {
1369                    rc->assymetric_tax_ratio = 1.0f;
1370            }
1371    
1372            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Assymetric tax ratio:%.2f\n", rc->assymetric_tax_ratio);
1373    
1374            /* Last bits that need to be reset */
1375            rc->overflow = 0;
1376            rc->KFoverflow = 0;
1377            rc->KFoverflow_partial = 0;
1378            rc->KF_idx = 0;
1379            rc->desired_total = 0;
1380            rc->real_total = 0;
1381    
1382            /* Job done */
1383            return;
1384    }
1385    
1386    /*****************************************************************************
1387     * Still more low level stuff (nothing to do with stats treatment)
1388     ****************************************************************************/
1389    
1390    /* This function returns an allocated string containing a complete line read
1391     * from the file starting at the current position */
1392    static char *
1393    readline(FILE *f)
1394    {
1395            char *buffer = NULL;
1396            int buffer_size = 0;
1397            int pos = 0;
1398    
1399            do {
1400                    int c;
1401    
1402                    /* Read a character from the stream */
1403                    c = fgetc(f);
1404    
1405                    /* Is that EOF or new line ? */
1406                    if(c == EOF || c == '\n')
1407                            break;
1408    
1409                    /* Do we have to update buffer ? */
1410                    if(pos >= buffer_size - 1) {
1411                            buffer_size += BUF_SZ;
1412                            buffer = (char*)realloc(buffer, buffer_size);
1413                            if (buffer == NULL)
1414                                    return(NULL);
1415                    }
1416    
1417                    buffer[pos] = c;
1418                    pos++;
1419            } while(1);
1420    
1421            /* Read \n or EOF */
1422            if (buffer == NULL) {
1423                    /* EOF, so we reached the end of the file, return NULL */
1424                    if(feof(f))
1425                            return(NULL);
1426    
1427                    /* Just an empty line with just a newline, allocate a 1 byte buffer to
1428                     * store a zero length string */
1429                    buffer = (char*)malloc(1);
1430                    if(buffer == NULL)
1431                            return(NULL);
1432            }
1433    
1434            /* Zero terminated string */
1435            buffer[pos] = '\0';
1436    
1437            return(buffer);
1438    }
1439    
1440    /* This function returns a pointer to the first non space char in the given
1441     * string */
1442    static char *
1443    skipspaces(char *string)
1444    {
1445            const char spaces[] =
1446                    {
1447                            ' ','\t','\0'
1448                    };
1449            const char *spacechar = spaces;
1450    
1451            if (string == NULL) return(NULL);
1452    
1453            while (*string != '\0') {
1454                    /* Test against space chars */
1455                    while (*spacechar != '\0') {
1456                            if (*string == *spacechar) {
1457                                    string++;
1458                                    spacechar = spaces;
1459                                    break;
1460                            }
1461                            spacechar++;
1462                    }
1463    
1464                    /* No space char */
1465                    if (*spacechar == '\0') return(string);
1466            }
1467    
1468            return(string);
1469    }
1470    
1471    /* This function returns a boolean that tells if the string is only a
1472     * comment */
1473    static int
1474    iscomment(char *string)
1475    {
1476            const char comments[] =
1477                    {
1478                            '#',';', '%', '\0'
1479                    };
1480            const char *cmtchar = comments;
1481            int iscomment = 0;
1482    
1483            if (string == NULL) return(1);
1484    
1485            string = skipspaces(string);
1486    
1487            while(*cmtchar != '\0') {
1488                    if(*string == *cmtchar) {
1489                            iscomment = 1;
1490                            break;
1491                    }
1492                    cmtchar++;
1493            }
1494    
1495            return(iscomment);
1496    }
1497    
1498    #if 0
1499    static void
1500    stats_print(rc_2pass2_t * rc)
1501    {
1502            int i;
1503            const char frame_type[4] = { 'i', 'p', 'b', 's'};
1504    
1505            for (i=0; i<rc->num_frames; i++) {
1506                    twopass_stat_t *s = &rc->stats[i];
1507                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- frame:%d type:%c quant:%d stats:%d scaled:%d desired:%d actual:%d overflow(%c):%.2f\n",
1508                                    i, frame_type[s->type-1], -1, s->length, s->scaled_length,
1509                                    s->desired_length, -1, frame_type[s->type-1], -1.0f);
1510            }
1511    }
1512    #endif
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