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revision 1.1, Tue Mar 25 10:58:33 2003 UTC revision 1.1.2.31, Wed Dec 17 15:16:16 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    #include <stdio.h>
36    #include <math.h>
37    #include <limits.h>
38    
39    #include "../xvid.h"
40    #include "../image/image.h"
41    
42    /*****************************************************************************
43     * Some default settings
44     ****************************************************************************/
45    
46    #define DEFAULT_KEYFRAME_BOOST 0
47    #define DEFAULT_OVERFLOW_CONTROL_STRENGTH 10
48    #define DEFAULT_CURVE_COMPRESSION_HIGH 0
49    #define DEFAULT_CURVE_COMPRESSION_LOW 0
50    #define DEFAULT_MAX_OVERFLOW_IMPROVEMENT 10
51    #define DEFAULT_MAX_OVERFLOW_DEGRADATION 10
52    
53    /* Keyframe settings */
54    #define DEFAULT_KFREDUCTION 20
55    #define DEFAULT_KFTHRESHOLD 1
56    
57    /*****************************************************************************
58     * Some default constants (can be tuned)
59     ****************************************************************************/
60    
61    /* Specify the invariant part of the headers bits (header+MV)
62     * as  hlength/cst */
63    #define INVARIANT_HEADER_PART_IVOP 1 /* factor 1.0f   */
64    #define INVARIANT_HEADER_PART_PVOP 2 /* factor 0.5f   */
65    #define INVARIANT_HEADER_PART_BVOP 8 /* factor 0.125f */
66    
67    /*****************************************************************************
68     * Structures
69     ****************************************************************************/
70    
71    /* Statistics */
72    typedef struct {
73            int type;               /* first pass type */
74            int quant;              /* first pass quant */
75            int blks[3];            /* k,m,y blks */
76            int length;             /* first pass length */
77            int invariant;          /* what we assume as being invariant between the two passes, it's a sub part of header + MV bits */
78            int scaled_length;      /* scaled length */
79            int desired_length;     /* desired length; calculated during encoding */
80            int error;
81    
82            int zone_mode;   /* XVID_ZONE_xxx */
83            double weight;
84    } twopass_stat_t;
85    
86    /* Context struct */
87    typedef struct
88    {
89            xvid_plugin_2pass2_t param;
90    
91            /*----------------------------------
92             * constant statistical data
93             *--------------------------------*/
94    
95            /* Number of frames of the sequence */
96            int num_frames;
97    
98            /* Number of Intra frames of the sequence */
99            int num_keyframes;
100    
101            /* Target filesize to reach */
102            uint64_t target;
103    
104            /* Count of each frame types */
105            int count[3];
106    
107            /* Total length of each frame types (1st pass) */
108            uint64_t tot_length[3];
109            uint64_t tot_invariant[3];
110    
111            /* Average length of each frame types (used first for 1st pass data and
112             * then for scaled averages */
113            double avg_length[3];
114    
115            /* Minimum frame length allowed for each frame type */
116            int min_length[3];
117    
118            /* Total bytes per frame type once the curve has been scaled
119             * NB: advanced parameters do not change this value. This field
120             *     represents the total scaled w/o any advanced settings */
121            uint64_t tot_scaled_length[3];
122    
123            /* Maximum observed frame size observed during the first pass, the RC
124             * will try tp force all frame sizes in the second pass to be under that
125             * limit */
126            int max_length;
127    
128            /*----------------------------------
129             * Zones statistical data
130             *
131             * ToDo: Fix zones, current
132             *       implementation is buggy
133             *--------------------------------*/
134    
135            /* Average weight of the zones */
136            double avg_weight;
137    
138            /* Total length used by XVID_ZONE_QUANT zones */
139            uint64_t tot_quant;
140            uint64_t tot_quant_invariant;
141    
142            /*----------------------------------
143             * Advanced settings helper ratios
144             *--------------------------------*/
145    
146            /* This the ratio that has to be applied to all p/b frames in order
147             * to reserve/retrieve bits for/from keyframe boosting and consecutive
148             * keyframe penalty */
149            double pb_iboost_tax_ratio;
150    
151            /* This the ratio to apply to all b/p frames in order to respect the
152             * assymetric curve compression while respecting a target filesize
153             * NB: The assymetric delta gain has to be computed before this ratio
154             *     is applied, and then the delta is added to the scaled size */
155            double assymetric_tax_ratio;
156    
157            /*----------------------------------
158             * Data from the stats file kept
159             * into RAM for easy access
160             *--------------------------------*/
161    
162            /* Array of keyframe locations
163             * eg: rc->keyframe_locations[100] returns the frame number of the 100th
164             *     keyframe */
165            int *keyframe_locations;
166    
167            /* Index of the last keyframe used in the keyframe_location */
168            int KF_idx;
169    
170            /* Array of all 1st pass data file -- see the twopass_stat_t structure
171             * definition for more details */
172            twopass_stat_t * stats;
173    
174            /*----------------------------------
175             * Histerysis helpers
176             *--------------------------------*/
177    
178            /* This field holds the int2float conversion errors of each quant per
179             * frame type, this allow the RC to keep track of rouding error and thus
180             * increase or decrease the chosen quant according to this residue */
181            double quant_error[3][32];
182    
183            /* This fields stores the count of each quant usage per frame type
184             * No real role but for debugging */
185            int quant_count[3][32];
186    
187            /* Last valid quantizer used per frame type, it allows quantizer
188             * increament/decreament limitation in order to avoid big image quality
189             * "jumps" */
190            int last_quant[3];
191    
192            /*----------------------------------
193             * Overflow control
194             *--------------------------------*/
195    
196            /* Current overflow that has to be distributed to p/b frames */
197            double overflow;
198    
199            /* Total overflow for keyframes -- not distributed directly */
200            double KFoverflow;
201    
202            /* Amount of keyframe overflow to introduce to the global p/b frame
203             * overflow counter at each encoded frame */
204            double KFoverflow_partial;
205    
206            /* Unknown ???
207             * ToDo: description */
208            double fq_error;
209    
210            /*----------------------------------
211             * Debug
212             *--------------------------------*/
213            double desired_total;
214            double real_total;
215    } rc_2pass2_t;
216    
217    
218    /*****************************************************************************
219     * Sub plugin functions prototypes
220     ****************************************************************************/
221    
222    static int rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t ** handle);
223    static int rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data);
224    static int rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data);
225    static int rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy);
226    
227    /*****************************************************************************
228     * Plugin definition
229     ****************************************************************************/
230    
231    int
232    xvid_plugin_2pass2(void * handle, int opt, void * param1, void * param2)
233    {
234            switch(opt) {
235            case XVID_PLG_INFO :
236            case XVID_PLG_FRAME :
237                    return 0;
238    
239            case XVID_PLG_CREATE :
240                    return rc_2pass2_create((xvid_plg_create_t*)param1, param2);
241    
242            case XVID_PLG_DESTROY :
243                    return rc_2pass2_destroy((rc_2pass2_t*)handle, (xvid_plg_destroy_t*)param1);
244    
245            case XVID_PLG_BEFORE :
246                    return rc_2pass2_before((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
247    
248            case XVID_PLG_AFTER :
249                    return rc_2pass2_after((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
250            }
251    
252            return XVID_ERR_FAIL;
253    }
254    
255    /*****************************************************************************
256     * Sub plugin functions definitions
257     ****************************************************************************/
258    
259    /* First a few local helping function prototypes */
260    static  int statsfile_count_frames(rc_2pass2_t * rc, char * filename);
261    static  int statsfile_load(rc_2pass2_t *rc, char * filename);
262    static void zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create);
263    static void first_pass_stats_prepare_data(rc_2pass2_t * rc);
264    static void first_pass_scale_curve_internal(rc_2pass2_t *rc);
265    static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);
266    #if 0
267    static void stats_print(rc_2pass2_t * rc);
268    #endif
269    
270    /*----------------------------------------------------------------------------
271     *--------------------------------------------------------------------------*/
272    
273    static int
274    rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t **handle)
275    {
276            xvid_plugin_2pass2_t * param = (xvid_plugin_2pass2_t *)create->param;
277            rc_2pass2_t * rc;
278            int i;
279    
280            rc = malloc(sizeof(rc_2pass2_t));
281            if (rc == NULL)
282                    return XVID_ERR_MEMORY;
283    
284            rc->param = *param;
285    
286            /* Initialize all defaults */
287    #define _INIT(a, b) if((a) <= 0) (a) = (b)
288            /* Let's set our defaults if needed */
289            _INIT(rc->param.keyframe_boost, DEFAULT_KEYFRAME_BOOST);
290            _INIT(rc->param.overflow_control_strength, DEFAULT_OVERFLOW_CONTROL_STRENGTH);
291            _INIT(rc->param.curve_compression_high, DEFAULT_CURVE_COMPRESSION_HIGH);
292            _INIT(rc->param.curve_compression_low, DEFAULT_CURVE_COMPRESSION_LOW);
293            _INIT(rc->param.max_overflow_improvement, DEFAULT_MAX_OVERFLOW_IMPROVEMENT);
294            _INIT(rc->param.max_overflow_degradation,  DEFAULT_MAX_OVERFLOW_DEGRADATION);
295    
296            /* Keyframe settings */
297            _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);
298            _INIT(rc->param.kfthreshold, DEFAULT_KFTHRESHOLD);
299    #undef _INIT
300    
301            /* Initialize some stuff to zero */
302            for(i=0; i<3; i++) {
303                    int j;
304                    for (j=0; j<32; j++) {
305                            rc->quant_error[i][j] = 0;
306                            rc->quant_count[i][j] = 0;
307                    }
308            }
309    
310            for (i=0; i<3; i++) rc->last_quant[i] = 0;
311    
312            rc->fq_error = 0;
313    
314            /* Count frames (and intra frames) in the stats file, store the result into
315             * the rc structure */
316            if (statsfile_count_frames(rc, param->filename) == -1) {
317                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
318                    free(rc);
319                    return(XVID_ERR_FAIL);
320            }
321    
322            /* Allocate the stats' memory */
323            if ((rc->stats = malloc(rc->num_frames * sizeof(twopass_stat_t))) == NULL) {
324                    free(rc);
325                    return(XVID_ERR_MEMORY);
326            }
327    
328            /* Allocate keyframes location's memory
329             * PS: see comment in pre_process0 for the +1 location requirement */
330            rc->keyframe_locations = malloc((rc->num_keyframes + 1) * sizeof(int));
331            if (rc->keyframe_locations == NULL) {
332                    free(rc->stats);
333                    free(rc);
334                    return(XVID_ERR_MEMORY);
335            }
336    
337            /* Load the first pass stats */
338            if (statsfile_load(rc, param->filename) == -1) {
339                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
340                    free(rc->keyframe_locations);
341                    free(rc->stats);
342                    free(rc);
343                    return XVID_ERR_FAIL;
344            }
345    
346            /* Compute the target filesize */
347            if (rc->param.bitrate<0) {
348                    /* if negative, bitrate equals the target (in kbytes) */
349                    rc->target = ((uint64_t)(-rc->param.bitrate)) * 1024;
350            } else if (rc->num_frames  < create->fbase/create->fincr) {
351                    /* Source sequence is less than 1s long, we do as if it was 1s long */
352                    rc->target = rc->param.bitrate / 8;
353            } else {
354                    /* Target filesize = bitrate/8 * numframes / framerate */
355                    rc->target =
356                            ((uint64_t)rc->param.bitrate * (uint64_t)rc->num_frames * \
357                             (uint64_t)create->fincr) / \
358                            ((uint64_t)create->fbase * 8);
359            }
360    
361            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Frame rate: %d/%d (%ffps)\n",
362                            create->fbase, create->fincr,
363                            (double)create->fbase/(double)create->fincr);
364            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Number of frames: %d\n", rc->num_frames);
365            if(rc->param.bitrate>=0)
366                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target bitrate: %ld\n", rc->param.bitrate);
367            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target filesize: %lld\n", rc->target);
368    
369            /* Compensate the average frame overhead caused by the container */
370            rc->target -= rc->num_frames*rc->param.container_frame_overhead;
371            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Container Frame overhead: %d\n", rc->param.container_frame_overhead);
372            if(rc->param.container_frame_overhead)
373                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- New target filesize after container compensation: %lld\n", rc->target);
374    
375            /* Gathers some information about first pass stats:
376             *  - finds the minimum frame length for each frame type during 1st pass.
377             *     rc->min_size[]
378             *  - determines the maximum frame length observed (no frame type distinction).
379             *     rc->max_size
380             *  - count how many times each frame type has been used.
381             *     rc->count[]
382             *  - total bytes used per frame type
383             *     rc->tot_length[]
384             *  - total bytes considered invariant between the 2 passes
385             *  - store keyframe location
386             *     rc->keyframe_locations[]
387             */
388            first_pass_stats_prepare_data(rc);
389    
390            /* When bitrate is not given it means it has been scaled by an external
391             * application */
392            if (rc->param.bitrate) {
393                    /* Apply zone settings
394                     * - set rc->tot_quant which represents the total num of bytes spent in
395                     *   fixed quant zones
396                     * - set rc->tot_quant_invariant which represents the total num of bytes spent
397                     *   in fixed quant zones for headers */
398                    zone_process(rc, create);
399                    /* Perform internal curve scaling */
400                    first_pass_scale_curve_internal(rc);
401            } else {
402                    /* External scaling -- zones are ignored */
403                    for (i=0;i<rc->num_frames;i++) {
404                            rc->stats[i].zone_mode = XVID_ZONE_WEIGHT;
405                            rc->stats[i].weight = 1.0;
406                    }
407                    rc->avg_weight = 1.0;
408                    rc->tot_quant = 0;
409            }
410    
411            /* Apply advanced curve options, and compute some parameters in order to
412             * shape the curve in the BEFORE/AFTER pair of functions */
413            scaled_curve_apply_advanced_parameters(rc);
414    
415            *handle = rc;
416            return(0);
417    }
418    
419    /*----------------------------------------------------------------------------
420     *--------------------------------------------------------------------------*/
421    
422    static int
423    rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy)
424    {
425            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- target_total:%lld desired_total:%.2f (%.2f%%) actual_total:%.2f (%.2f%%)\n",
426                            rc->target,
427                            rc->desired_total,
428                            100*rc->desired_total/(double)rc->target,
429                            rc->real_total,
430                            100*rc->real_total/(double)rc->target);
431    
432            free(rc->keyframe_locations);
433            free(rc->stats);
434            free(rc);
435            return(0);
436    }
437    
438    /*----------------------------------------------------------------------------
439     *--------------------------------------------------------------------------*/
440    
441    static int
442    rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data)
443    {
444            twopass_stat_t * s = &rc->stats[data->frame_num];
445            double dbytes;
446            double scaled_quant;
447            double overflow;
448            int capped_to_max_framesize = 0;
449    
450            /* This function is quite long but easy to understand. In order to simplify
451             * the code path (a bit), we treat 3 cases that can return immediatly. */
452    
453            /* First case: Another plugin has already set a quantizer */
454            if (data->quant > 0)
455                    return(0);
456    
457            /* Second case: insufficent stats data */
458            if (data->frame_num >= rc->num_frames) {
459                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- stats file too short (now processing frame %d)",
460                            data->frame_num);
461                    return(0);
462            }
463    
464            /* Third case: We are in a Quant zone */
465            if (s->zone_mode == XVID_ZONE_QUANT) {
466                    rc->fq_error += s->weight;
467                    data->quant = (int)rc->fq_error;
468                    rc->fq_error -= data->quant;
469    
470                    s->desired_length = s->length;
471    
472                    return(0);
473            }
474    
475    
476            /*************************************************************************/
477            /*************************************************************************/
478            /*************************************************************************/
479    
480            /*-------------------------------------------------------------------------
481             * Frame bit allocation first part
482             *
483             * First steps apply user settings, just like it is done in the theoritical
484             * scaled_curve_apply_advanced_parameters
485             *-----------------------------------------------------------------------*/
486    
487            /* Set desired to what we are wanting to obtain for this frame */
488            dbytes = (double)s->scaled_length;
489    
490            /* IFrame user settings*/
491            if (s->type == XVID_TYPE_IVOP) {
492                    /* Keyframe boosting -- All keyframes benefit from it */
493                    dbytes += dbytes*rc->param.keyframe_boost / 100;
494    
495    #if 0 /* ToDo: decide how to apply kfthresholding */
496    #endif
497            } else {
498    
499                    /* P/S/B frames must reserve some bits for iframe boosting */
500                    dbytes *= rc->pb_iboost_tax_ratio;
501    
502                    /* Apply assymetric curve compression */
503                    if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
504                            double assymetric_delta;
505    
506                            /* Compute the assymetric delta, this is computed before applying
507                             * the tax, as done in the pre_process function */
508                            if (dbytes > rc->avg_length[s->type-1])
509                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_high / 100.0;
510                            else
511                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_low  / 100.0;
512    
513                            /* Now we must apply the assymetric tax, else our curve compression
514                             * would not give a theoritical target size equal to what it is
515                             * expected */
516                            dbytes *= rc->assymetric_tax_ratio;
517    
518                            /* Now we can add the assymetric delta */
519                            dbytes += assymetric_delta;
520                    }
521            }
522    
523            /* That is what we would like to have -- Don't put that chunk after
524             * overflow control, otherwise, overflow is counted twice and you obtain
525             * half sized bitrate sequences */
526            s->desired_length  = (int)dbytes;
527            rc->desired_total += dbytes;
528    
529            /*------------------------------------------------------------------------
530             * Frame bit allocation: overflow control part.
531             *
532             * Unlike the theoritical scaled_curve_apply_advanced_parameters, here
533             * it's real encoding and we need to make sure we don't go so far from
534             * what is our ideal scaled curve.
535             *-----------------------------------------------------------------------*/
536    
537            /* Compute the overflow we should compensate */
538            if (s->type != XVID_TYPE_IVOP) {
539                    double frametype_factor;
540                    double framesize_factor;
541    
542                    /* Take only the desired part of overflow */
543                    overflow = rc->overflow;
544    
545                    /* Factor that will take care to decrease the overflow applied
546                     * according to the importance of this frame type in term of
547                     * overall size */
548                    frametype_factor  = rc->count[XVID_TYPE_IVOP-1]*rc->avg_length[XVID_TYPE_IVOP-1];
549                    frametype_factor += rc->count[XVID_TYPE_PVOP-1]*rc->avg_length[XVID_TYPE_PVOP-1];
550                    frametype_factor += rc->count[XVID_TYPE_BVOP-1]*rc->avg_length[XVID_TYPE_BVOP-1];
551                    frametype_factor /= rc->count[s->type-1]*rc->avg_length[s->type-1];
552                    frametype_factor  = 1/frametype_factor;
553    
554                    /* Factor that will take care not to compensate too much for this frame
555                     * size */
556                    framesize_factor  = dbytes;
557                    framesize_factor /= rc->avg_length[s->type-1];
558    
559                    /* Treat only the overflow part concerned by this frame type and size */
560                    overflow *= frametype_factor;
561    #if 0
562                    /* Leave this one alone, as it impacts badly on quality */
563                    overflow *= framesize_factor;
564    #endif
565    
566                    /* Apply the overflow strength imposed by the user */
567                    overflow *= (rc->param.overflow_control_strength/100.0f);
568            } else {
569                    /* no overflow applied in IFrames because:
570                     *  - their role is important as they're references for P/BFrames.
571                     *  - there aren't much in typical sequences, so if an IFrame overflows too
572                     *    much, this overflow may impact the next IFrame too much and generate
573                     *    a sequence of poor quality frames */
574                    overflow = 0;
575            }
576    
577            /* Make sure we are not trying to compensate more overflow than we even have */
578            if (fabs(overflow) > fabs(rc->overflow))
579                    overflow = rc->overflow;
580    
581            /* Make sure the overflow doesn't make the frame size to get out of the range
582             * [-max_degradation..+max_improvment] */
583            if (overflow > dbytes*rc->param.max_overflow_improvement / 100) {
584                    if(overflow <= dbytes)
585                            dbytes += dbytes * rc->param.max_overflow_improvement / 100;
586                    else
587                            dbytes += overflow * rc->param.max_overflow_improvement / 100;
588            } else if (overflow < - dbytes * rc->param.max_overflow_degradation / 100) {
589                    dbytes -= dbytes * rc->param.max_overflow_degradation / 100;
590            } else {
591                    dbytes += overflow;
592            }
593    
594            /*-------------------------------------------------------------------------
595             * Frame bit allocation last part:
596             *
597             * Cap frame length so we don't reach neither bigger frame sizes than first
598             * pass nor smaller than the allowed minimum.
599             *-----------------------------------------------------------------------*/
600    
601            if (dbytes > s->length) {
602                    dbytes = s->length;
603            } else if (dbytes < rc->min_length[s->type-1]) {
604                    dbytes = rc->min_length[s->type-1];
605            } else if (dbytes > rc->max_length) {
606                    /* ToDo: this condition is always wrong as max_length == maximum frame
607                     * length of first pass, so the first condition already caps the frame
608                     * size... */
609                    capped_to_max_framesize = 1;
610                    dbytes = rc->max_length;
611                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- frame:%d Capped to maximum frame size\n",
612                                    data->frame_num);
613            }
614    
615            /*------------------------------------------------------------------------
616             * Desired frame length <-> quantizer mapping
617             *-----------------------------------------------------------------------*/
618    
619    #ifdef BQUANT_PRESCALE
620            /* For bframes we prescale the quantizer to avoid too high quant scaling */
621            if(s->type == XVID_TYPE_BVOP) {
622    
623                    twopass_stat_t *b_ref = s;
624    
625                    /* Find the reference frame */
626                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
627                            b_ref--;
628    
629                    /* Compute the original quant */
630                    s->quant  = 2*(100*s->quant - data->bquant_offset);
631                    s->quant += data->bquant_ratio - 1; /* to avoid rounding issues */
632                    s->quant  = s->quant/data->bquant_ratio - b_ref->quant;
633            }
634    #endif
635    
636            /* Don't laugh at this very 'simple' quant<->size relationship, it
637             * proves to be acurate enough for our algorithm */
638            scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;
639    
640    #ifdef COMPENSATE_FORMULA
641            /* We know xvidcore will apply the bframe formula again, so we compensate
642             * it right now to make sure we would not apply it twice */
643            if(s->type == XVID_TYPE_BVOP) {
644    
645                    twopass_stat_t *b_ref = s;
646    
647                    /* Find the reference frame */
648                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
649                            b_ref--;
650    
651                    /* Compute the quant it would be if the core did not apply the bframe
652                     * formula */
653                    scaled_quant  = 100*scaled_quant - data->bquant_offset;
654                    scaled_quant += data->bquant_ratio - 1; /* to avoid rouding issues */
655                    scaled_quant /= data->bquant_ratio;
656            }
657    #endif
658    
659            /* Quantizer has been scaled using floating point operations/results, we
660             * must cast it to integer */
661            data->quant = (int)scaled_quant;
662    
663            /* Let's clip the computed quantizer, if needed */
664            if (data->quant < 1) {
665                    data->quant = 1;
666            } else if (data->quant > 31) {
667                    data->quant = 31;
668            } else {
669    
670                    /* The frame quantizer has not been clipped, this appears to be a good
671                     * computed quantizer, do not loose quantizer decimal part that we
672                     * accumulate for later reuse when its sum represents a complete
673                     * unit. */
674                    rc->quant_error[s->type-1][data->quant] += scaled_quant - (double)data->quant;
675    
676                    if (rc->quant_error[s->type-1][data->quant] >= 1.0) {
677                            rc->quant_error[s->type-1][data->quant] -= 1.0;
678                            data->quant++;
679                    } else if (rc->quant_error[s->type-1][data->quant] <= -1.0) {
680                            rc->quant_error[s->type-1][data->quant] += 1.0;
681                            data->quant--;
682                    }
683            }
684    
685            /* Now we have a computed quant that is in the right quante range, with a
686             * possible +1 correction due to cumulated error. We can now safely clip
687             * the quantizer again with user's quant ranges. "Safely" means the Rate
688             * Control could learn more about this quantizer, this knowledge is useful
689             * for future frames even if it this quantizer won't be really used atm,
690             * that's why we don't perform this clipping earlier. */
691            if (data->quant < data->min_quant[s->type-1]) {
692                    data->quant = data->min_quant[s->type-1];
693            } else if (data->quant > data->max_quant[s->type-1]) {
694                    data->quant = data->max_quant[s->type-1];
695            }
696    
697            /* To avoid big quality jumps from frame to frame, we apply a "security"
698             * rule that makes |last_quant - new_quant| <= 2. This rule only applies
699             * to predicted frames (P and B) */
700            if (s->type != XVID_TYPE_IVOP && rc->last_quant[s->type-1] && capped_to_max_framesize == 0) {
701    
702                    if (data->quant > rc->last_quant[s->type-1] + 2) {
703                            data->quant = rc->last_quant[s->type-1] + 2;
704                            DPRINTF(XVID_DEBUG_RC,
705                                            "[xvid rc] -- frame %d p/b-frame quantizer prevented from rising too steeply\n",
706                                            data->frame_num);
707                    }
708                    if (data->quant < rc->last_quant[s->type-1] - 2) {
709                            data->quant = rc->last_quant[s->type-1] - 2;
710                            DPRINTF(XVID_DEBUG_RC,
711                                            "[xvid rc] -- frame:%d p/b-frame quantizer prevented from falling too steeply\n",
712                                            data->frame_num);
713                    }
714            }
715    
716            /* We don't want to pollute the RC histerisis when our computed quant has
717             * been computed from a capped frame size */
718            if (capped_to_max_framesize == 0)
719                    rc->last_quant[s->type-1] = data->quant;
720    
721            /* Don't forget to force 1st pass frame type ;-) */
722            data->type = s->type;
723    
724            return 0;
725    }
726    
727    /*----------------------------------------------------------------------------
728     *--------------------------------------------------------------------------*/
729    
730    static int
731    rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data)
732    {
733            const char frame_type[4] = { 'i', 'p', 'b', 's'};
734            twopass_stat_t * s = &rc->stats[data->frame_num];
735    
736            /* Insufficent stats data */
737            if (data->frame_num >= rc->num_frames)
738                    return 0;
739    
740            /* Update the quantizer counter */
741            rc->quant_count[s->type-1][data->quant]++;
742    
743            /* Update the frame type overflow */
744            if (data->type == XVID_TYPE_IVOP) {
745                    int kfdiff = 0;
746    
747                    if(rc->KF_idx != rc->num_frames -1) {
748                            kfdiff  = rc->keyframe_locations[rc->KF_idx+1];
749                            kfdiff -= rc->keyframe_locations[rc->KF_idx];
750                    }
751    
752                    /* Flush Keyframe overflow accumulator */
753                    rc->overflow += rc->KFoverflow;
754    
755                    /* Store the frame overflow to the keyframe accumulator */
756                    rc->KFoverflow = s->desired_length - data->length;
757    
758                    if (kfdiff > 1) {
759                            /* Non-consecutive keyframes case:
760                             * We can then divide this total keyframe overflow into equal parts
761                             * that we will distribute into regular overflow at each frame
762                             * between the sequence bounded by two IFrames */
763                            rc->KFoverflow_partial = rc->KFoverflow / (kfdiff - 1);
764                    } else {
765                            /* Consecutive keyframes case:
766                             * Flush immediatly the keyframe overflow and reset keyframe
767                             * overflow */
768                            rc->overflow += rc->KFoverflow;
769                            rc->KFoverflow = 0;
770                            rc->KFoverflow_partial = 0;
771                    }
772                    rc->KF_idx++;
773            } else {
774                    /* Accumulate the frame overflow */
775                    rc->overflow += s->desired_length - data->length;
776    
777                    /* Distribute part of the keyframe overflow */
778                    rc->overflow += rc->KFoverflow_partial;
779    
780                    /* Don't forget to substract that same amount from the total keyframe
781                     * overflow */
782                    rc->KFoverflow -= rc->KFoverflow_partial;
783            }
784    
785            rc->overflow += (s->error = s->desired_length - data->length);
786            rc->real_total += data->length;
787    
788            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",
789                            data->frame_num,
790                            frame_type[data->type-1],
791                            data->quant,
792                            s->length,
793                            s->scaled_length,
794                            s->desired_length,
795                            s->desired_length - s->error,
796                            -s->error,
797                            rc->overflow);
798    
799            return(0);
800    }
801    
802    /*****************************************************************************
803     * Helper functions definition
804     ****************************************************************************/
805    
806    /* Default buffer size for reading lines */
807    #define BUF_SZ   1024
808    
809    /* Helper functions for reading/parsing the stats file */
810    static char *skipspaces(char *string);
811    static int iscomment(char *string);
812    static char *readline(FILE *f);
813    
814    /* This function counts the number of frame entries in the stats file
815     * It also counts the number of I Frames */
816    static int
817    statsfile_count_frames(rc_2pass2_t * rc, char * filename)
818    {
819            FILE * f;
820            char *line;
821            int lines;
822    
823            rc->num_frames = 0;
824            rc->num_keyframes = 0;
825    
826            if ((f = fopen(filename, "rb")) == NULL)
827                    return(-1);
828    
829            lines = 0;
830            while ((line = readline(f)) != NULL) {
831    
832                    char *ptr;
833                    char type;
834                    int fields;
835    
836                    lines++;
837    
838                    /* We skip spaces */
839                    ptr = skipspaces(line);
840    
841                    /* Skip coment lines or empty lines */
842                    if(iscomment(ptr) || *ptr == '\0') {
843                            free(line);
844                            continue;
845                    }
846    
847                    /* Read the stat line from buffer */
848                    fields = sscanf(ptr, "%c", &type);
849    
850                    /* Valid stats files have at least 7 fields */
851                    if (fields == 1) {
852                            switch(type) {
853                            case 'i':
854                            case 'I':
855                                    rc->num_keyframes++;
856                            case 'p':
857                            case 'P':
858                            case 'b':
859                            case 'B':
860                            case 's':
861                            case 'S':
862                                    rc->num_frames++;
863                                    break;
864                            default:
865                                    DPRINTF(XVID_DEBUG_RC,
866                                                    "[xvid rc] -- WARNING: L%d unknown frame type used (%c).\n",
867                                                    lines, type);
868                            }
869                    } else {
870                                    DPRINTF(XVID_DEBUG_RC,
871                                                    "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",
872                                                    lines, 7-fields);
873                    }
874    
875                    /* Free the line buffer */
876                    free(line);
877            }
878    
879            /* We are done with the file */
880            fclose(f);
881    
882            return(0);
883    }
884    
885    /* open stats file(s) and read into rc->stats array */
886    static int
887    statsfile_load(rc_2pass2_t *rc, char * filename)
888    {
889            FILE * f;
890            int processed_entries;
891    
892            /* Opens the file */
893            if ((f = fopen(filename, "rb"))==NULL)
894                    return(-1);
895    
896            processed_entries = 0;
897            while(processed_entries < rc->num_frames) {
898                    char type;
899                    int fields;
900                    twopass_stat_t * s = &rc->stats[processed_entries];
901                    char *line, *ptr;
902    
903                    /* Read the line from the file */
904                    if((line = readline(f)) == NULL)
905                            break;
906    
907                    /* We skip spaces */
908                    ptr = skipspaces(line);
909    
910                    /* Skip comment lines or empty lines */
911                    if(iscomment(ptr) || *ptr == '\0') {
912                            free(line);
913                            continue;
914                    }
915    
916                    /* Reset this field that is optional */
917                    s->scaled_length = 0;
918    
919                    /* Convert the fields */
920                    fields = sscanf(ptr,
921                                                    "%c %d %d %d %d %d %d %d\n",
922                                                    &type,
923                                                    &s->quant,
924                                                    &s->blks[0], &s->blks[1], &s->blks[2],
925                                                    &s->length, &s->invariant /* not really yet */,
926                                                    &s->scaled_length);
927    
928                    /* Free line buffer, we don't need it anymore */
929                    free(line);
930    
931                    /* Fail silently, this has probably been warned in
932                     * statsfile_count_frames */
933                    if(fields != 7 && fields != 8)
934                            continue;
935    
936                    /* Convert frame type and compute the invariant length part */
937                    switch(type) {
938                    case 'i':
939                    case 'I':
940                            s->type = XVID_TYPE_IVOP;
941                            s->invariant /= INVARIANT_HEADER_PART_IVOP;
942                            break;
943                    case 'p':
944                    case 'P':
945                    case 's':
946                    case 'S':
947                            s->type = XVID_TYPE_PVOP;
948                            s->invariant /= INVARIANT_HEADER_PART_PVOP;
949                            break;
950                    case 'b':
951                    case 'B':
952                            s->type = XVID_TYPE_BVOP;
953                            s->invariant /= INVARIANT_HEADER_PART_BVOP;
954                            break;
955                    default:
956                            /* Same as before, fail silently */
957                            continue;
958                    }
959    
960                    /* Ok it seems it's been processed correctly */
961                    processed_entries++;
962            }
963    
964            /* Close the file */
965            fclose(f);
966    
967            return(0);
968    }
969    
970    /* pre-process the statistics data
971     * - for each type, count, tot_length, min_length, max_length
972     * - set keyframes_locations */
973    static void
974    first_pass_stats_prepare_data(rc_2pass2_t * rc)
975    {
976            int i,j;
977    
978            /* *rc fields initialization
979             * NB: INT_MAX and INT_MIN are used in order to be immediately replaced
980             *     with real values of the 1pass */
981            for (i=0; i<3; i++) {
982                    rc->count[i]=0;
983                    rc->tot_length[i] = 0;
984                    rc->tot_invariant[i] = 0;
985                    rc->min_length[i] = INT_MAX;
986            }
987    
988            rc->max_length = INT_MIN;
989    
990            /* Loop through all frames and find/compute all the stuff this function
991             * is supposed to do */
992            for (i=j=0; i<rc->num_frames; i++) {
993                    twopass_stat_t * s = &rc->stats[i];
994    
995                    rc->count[s->type-1]++;
996                    rc->tot_length[s->type-1] += s->length;
997                    rc->tot_invariant[s->type-1] += s->invariant;
998    
999                    if (s->length < rc->min_length[s->type-1]) {
1000                            rc->min_length[s->type-1] = s->length;
1001                    }
1002    
1003                    if (s->length > rc->max_length) {
1004                            rc->max_length = s->length;
1005                    }
1006    
1007                    if (s->type == XVID_TYPE_IVOP) {
1008                            rc->keyframe_locations[j] = i;
1009                            j++;
1010                    }
1011            }
1012    
1013            /* NB:
1014             * The "per sequence" overflow system considers a natural sequence to be
1015             * formed by all frames between two iframes, so if we want to make sure
1016             * the system does not go nuts during last sequence, we force the last
1017             * frame to appear in the keyframe locations array. */
1018            rc->keyframe_locations[j] = i;
1019    
1020            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass IFrame length: %d\n", rc->min_length[0]);
1021            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass PFrame length: %d\n", rc->min_length[1]);
1022            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass BFrame length: %d\n", rc->min_length[2]);
1023    }
1024    
1025    /* calculate zone weight "center" */
1026    static void
1027    zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create)
1028    {
1029            int i,j;
1030            int n = 0;
1031    
1032            rc->avg_weight = 0.0;
1033            rc->tot_quant = 0;
1034            rc->tot_quant_invariant = 0;
1035    
1036            if (create->num_zones == 0) {
1037                    for (j = 0; j < rc->num_frames; j++) {
1038                            rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1039                            rc->stats[j].weight = 1.0;
1040                    }
1041                    rc->avg_weight += rc->num_frames * 1.0;
1042                    n += rc->num_frames;
1043            }
1044    
1045    
1046            for(i=0; i < create->num_zones; i++) {
1047    
1048                    int next = (i+1<create->num_zones) ? create->zones[i+1].frame : rc->num_frames;
1049    
1050                    if (i==0 && create->zones[i].frame > 0) {
1051                            for (j = 0; j < create->zones[i].frame && j < rc->num_frames; j++) {
1052                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1053                                    rc->stats[j].weight = 1.0;
1054                            }
1055                            rc->avg_weight += create->zones[i].frame * 1.0;
1056                            n += create->zones[i].frame;
1057                    }
1058    
1059                    if (create->zones[i].mode == XVID_ZONE_WEIGHT) {
1060                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1061                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1062                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1063                            }
1064                            next -= create->zones[i].frame;
1065                            rc->avg_weight += (double)(next * create->zones[i].increment) / (double)create->zones[i].base;
1066                            n += next;
1067                    } else{  /* XVID_ZONE_QUANT */
1068                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1069                                    rc->stats[j].zone_mode = XVID_ZONE_QUANT;
1070                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1071                                    rc->tot_quant += rc->stats[j].length;
1072                                    rc->tot_quant_invariant += rc->stats[j].invariant;
1073                            }
1074                    }
1075            }
1076            rc->avg_weight = n>0 ? rc->avg_weight/n : 1.0;
1077    
1078            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- center_weight:%f (for %d frames)  fixed_bytes:%d\n", rc->avg_weight, n, rc->tot_quant);
1079    }
1080    
1081    
1082    /* scale the curve */
1083    static void
1084    first_pass_scale_curve_internal(rc_2pass2_t *rc)
1085    {
1086            int64_t target;
1087            int64_t pass1_length;
1088            int64_t total_invariant;
1089            double scaler;
1090            int i, num_MBs;
1091    
1092            /* We only scale texture data ! */
1093            total_invariant  = rc->tot_invariant[XVID_TYPE_IVOP-1];
1094            total_invariant += rc->tot_invariant[XVID_TYPE_PVOP-1];
1095            total_invariant += rc->tot_invariant[XVID_TYPE_BVOP-1];
1096            /* don't forget to substract header bytes used in quant zones, otherwise we
1097             * counting them twice */
1098            total_invariant -= rc->tot_quant_invariant;
1099    
1100            /* We remove the bytes used by the fixed quantizer zones during first pass
1101             * with the same quants, so we know very precisely how much that
1102             * represents */
1103            target  = rc->target;
1104            target -= rc->tot_quant;
1105    
1106            /* Do the same for the first pass data */
1107            pass1_length  = rc->tot_length[XVID_TYPE_IVOP-1];
1108            pass1_length += rc->tot_length[XVID_TYPE_PVOP-1];
1109            pass1_length += rc->tot_length[XVID_TYPE_BVOP-1];
1110            pass1_length -= rc->tot_quant;
1111    
1112            /* Let's compute a linear scaler in order to perform curve scaling */
1113            scaler = (double)(target - total_invariant) / (double)(pass1_length - total_invariant);
1114    
1115            if ((target - total_invariant) <= 0 ||
1116                    (pass1_length - total_invariant) <= 0 ||
1117                    target >= pass1_length) {
1118                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected before correction\n");
1119                    scaler = 1.0;
1120            }
1121    
1122            /* Compute min frame lengths (for each frame type) according to the number
1123             * of MBs. We sum all block type counters of frame 0, this gives us the
1124             * number of MBs.
1125             *
1126             * We compare these hardcoded values with observed values in first pass
1127             * (determined in pre_process0).Then we keep the real minimum. */
1128    
1129            /* Number of MBs */
1130            num_MBs  = rc->stats[0].blks[0];
1131            num_MBs += rc->stats[0].blks[1];
1132            num_MBs += rc->stats[0].blks[2];
1133    
1134            /* Minimum for I frames */
1135            if(rc->min_length[XVID_TYPE_IVOP-1] > ((num_MBs*22) + 240) / 8)
1136                    rc->min_length[XVID_TYPE_IVOP-1] = ((num_MBs*22) + 240) / 8;
1137    
1138            /* Minimum for P/S frames */
1139            if(rc->min_length[XVID_TYPE_PVOP-1] > ((num_MBs) + 88)  / 8)
1140                    rc->min_length[XVID_TYPE_PVOP-1] = ((num_MBs) + 88)  / 8;
1141    
1142            /* Minimum for B frames */
1143            if(rc->min_length[XVID_TYPE_BVOP-1] > 8)
1144                    rc->min_length[XVID_TYPE_BVOP-1] = 8;
1145    
1146            /* Perform an initial scale pass.
1147             *
1148             * If a frame size is scaled underneath our hardcoded minimums, then we
1149             * force the frame size to the minimum, and deduct the original & scaled
1150             * frame length from the original and target total lengths */
1151            for (i=0; i<rc->num_frames; i++) {
1152                    twopass_stat_t * s = &rc->stats[i];
1153                    int len;
1154    
1155                    /* No need to scale frame length for which a specific quantizer is
1156                     * specified thanks to zones */
1157                    if (s->zone_mode == XVID_ZONE_QUANT) {
1158                            s->scaled_length = s->length;
1159                            continue;
1160                    }
1161    
1162                    /* Compute the scaled length -- only non invariant data length is scaled */
1163                    len = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight / rc->avg_weight);
1164    
1165                    /* Compare with the computed minimum */
1166                    if (len < rc->min_length[s->type-1]) {
1167                            /* This is a 'forced size' frame, set its frame size to the
1168                             * computed minimum */
1169                            s->scaled_length = rc->min_length[s->type-1];
1170    
1171                            /* Remove both scaled and original size from their respective
1172                             * total counters, as we prepare a second pass for 'regular'
1173                             * frames */
1174                            target -= s->scaled_length;
1175                            pass1_length -= s->length;
1176                    } else {
1177                            /* Do nothing for now, we'll scale this later */
1178                            s->scaled_length = 0;
1179                    }
1180            }
1181    
1182            /* The first pass on data substracted all 'forced size' frames from the
1183             * total counters. Now, it's possible to scale the 'regular' frames. */
1184    
1185            /* Scaling factor for 'regular' frames */
1186            scaler = (double)(target - total_invariant) / (double)(pass1_length - total_invariant);
1187    
1188            /* Detect undersizing */
1189            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1190                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected after correction\n");
1191                    scaler = 1.0;
1192            }
1193    
1194            /* Do another pass with the new scaler */
1195            for (i=0; i<rc->num_frames; i++) {
1196                    twopass_stat_t * s = &rc->stats[i];
1197    
1198                    /* Ignore frame with forced frame sizes */
1199                    if (s->scaled_length == 0)
1200                            s->scaled_length = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight / rc->avg_weight);
1201            }
1202    
1203            /* Job done */
1204            return;
1205    }
1206    
1207    /* Apply all user settings to the scaled curve
1208     * This implies:
1209     *   keyframe boosting
1210     *   high/low compression */
1211    static void
1212    scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)
1213    {
1214            int i;
1215            int64_t ivop_boost_total;
1216    
1217            /* Reset the rate controller (per frame type) total byte counters */
1218            for (i=0; i<3; i++) rc->tot_scaled_length[i] = 0;
1219    
1220            /* Compute total bytes for each frame type */
1221            for (i=0; i<rc->num_frames;i++) {
1222                    twopass_stat_t *s = &rc->stats[i];
1223                    rc->tot_scaled_length[s->type-1] += s->scaled_length;
1224            }
1225    
1226            /* First we compute the total amount of bits needed, as being described by
1227             * the scaled distribution. During this pass over the complete stats data,
1228             * we see how much bits two user settings will get/give from/to p&b frames:
1229             *  - keyframe boosting
1230             *  - keyframe distance penalty */
1231            rc->KF_idx = 0;
1232            ivop_boost_total = 0;
1233            for (i=0; i<rc->num_frames; i++) {
1234                    twopass_stat_t * s = &rc->stats[i];
1235    
1236                    /* Some more work is needed for I frames */
1237                    if (s->type == XVID_TYPE_IVOP) {
1238                            int ivop_boost;
1239    
1240                            /* Accumulate bytes needed for keyframe boosting */
1241                            ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;
1242    
1243    #if 0 /* ToDo: decide how to apply kfthresholding */
1244    #endif
1245                            /* If the frame size drops under the minimum length, then cap ivop_boost */
1246                            if (ivop_boost + s->scaled_length < rc->min_length[XVID_TYPE_IVOP-1])
1247                                    ivop_boost = rc->min_length[XVID_TYPE_IVOP-1] - s->scaled_length;
1248    
1249                            /* Accumulate the ivop boost */
1250                            ivop_boost_total += ivop_boost;
1251    
1252                            /* Don't forget to update the keyframe index */
1253                            rc->KF_idx++;
1254                    }
1255            }
1256    
1257            /* Initialize the IBoost tax ratio for P/S/B frames
1258             *
1259             * This ratio has to be applied to p/b/s frames in order to reserve
1260             * additional bits for keyframes (keyframe boosting) or if too much
1261             * keyframe distance is applied, bits retrieved from the keyframes.
1262             *
1263             * ie pb_length *= rc->pb_iboost_tax_ratio;
1264             *
1265             *    gives the ideal length of a p/b frame */
1266    
1267            /* Compute the total length of p/b/s frames (temporary storage into
1268             * movie_curve) */
1269            rc->pb_iboost_tax_ratio  = (double)rc->tot_scaled_length[XVID_TYPE_PVOP-1];
1270            rc->pb_iboost_tax_ratio += (double)rc->tot_scaled_length[XVID_TYPE_BVOP-1];
1271    
1272            /* Compute the ratio described above
1273             *     taxed_total = sum(0, n, tax*scaled_length)
1274             * <=> taxed_total = tax.sum(0, n, scaled_length)
1275             * <=> tax = taxed_total / original_total */
1276            rc->pb_iboost_tax_ratio =
1277                    (rc->pb_iboost_tax_ratio - ivop_boost_total) /
1278                    rc->pb_iboost_tax_ratio;
1279    
1280            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- IFrame boost tax ratio:%.2f\n",
1281                            rc->pb_iboost_tax_ratio);
1282    
1283            /* Compute the average size of frames per frame type */
1284            for(i=0; i<3; i++) {
1285                    /* Special case for missing type or weird case */
1286                    if (rc->count[i] == 0 || rc->pb_iboost_tax_ratio == 0) {
1287                            rc->avg_length[i] = 1;
1288                    } else {
1289                            rc->avg_length[i] = rc->tot_scaled_length[i];
1290    
1291                            if (i == (XVID_TYPE_IVOP-1)) {
1292                                    /* I Frames total has to be added the boost total */
1293                                    rc->avg_length[i] += ivop_boost_total;
1294                            } else {
1295                                    /* P/B frames has to taxed */
1296                                    rc->avg_length[i] *= rc->pb_iboost_tax_ratio;
1297                            }
1298    
1299                            /* Finally compute the average frame size */
1300                            rc->avg_length[i] /= (double)rc->count[i];
1301                    }
1302            }
1303    
1304            /* Assymetric curve compression */
1305            if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
1306                    double symetric_total;
1307                    double assymetric_delta_total;
1308    
1309                    /* Like I frame boosting, assymetric curve compression modifies the total
1310                     * amount of needed bits, we must compute the ratio so we can prescale
1311                     lengths */
1312                    symetric_total = 0;
1313                    assymetric_delta_total = 0;
1314                    for (i=0; i<rc->num_frames; i++) {
1315                            double assymetric_delta;
1316                            double dbytes;
1317                            twopass_stat_t * s = &rc->stats[i];
1318    
1319                            /* I Frames are not concerned by assymetric scaling */
1320                            if (s->type == XVID_TYPE_IVOP)
1321                                    continue;
1322    
1323                            /* During the real run, we would have to apply the iboost tax */
1324                            dbytes = s->scaled_length * rc->pb_iboost_tax_ratio;
1325    
1326                            /* Update the symmetric curve compression total */
1327                            symetric_total += dbytes;
1328    
1329                            /* Apply assymetric curve compression */
1330                            if (dbytes > rc->avg_length[s->type-1])
1331                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_high / 100.0f;
1332                            else
1333                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_low  / 100.0f;
1334    
1335                            /* Cap to the minimum frame size if needed */
1336                            if (dbytes + assymetric_delta < rc->min_length[s->type-1])
1337                                    assymetric_delta = rc->min_length[s->type-1] - dbytes;
1338    
1339                            /* Accumulate after assymetric curve compression */
1340                            assymetric_delta_total += assymetric_delta;
1341                    }
1342    
1343                    /* Compute the tax that all p/b frames have to pay in order to respect the
1344                     * bit distribution changes that the assymetric compression curve imposes
1345                     * We want assymetric_total = sum(0, n-1, tax.scaled_length)
1346                     *      ie assymetric_total = ratio.sum(0, n-1, scaled_length)
1347                     *         ratio = assymetric_total / symmetric_total */
1348                    rc->assymetric_tax_ratio = ((double)symetric_total - (double)assymetric_delta_total) / (double)symetric_total;
1349            } else {
1350                    rc->assymetric_tax_ratio = 1.0f;
1351            }
1352    
1353            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Assymetric tax ratio:%.2f\n", rc->assymetric_tax_ratio);
1354    
1355            /* Last bits that need to be reset */
1356            rc->overflow = 0;
1357            rc->KFoverflow = 0;
1358            rc->KFoverflow_partial = 0;
1359            rc->KF_idx = 0;
1360            rc->desired_total = 0;
1361            rc->real_total = 0;
1362    
1363            /* Job done */
1364            return;
1365    }
1366    
1367    /*****************************************************************************
1368     * Still more low level stuff (nothing to do with stats treatment)
1369     ****************************************************************************/
1370    
1371    /* This function returns an allocated string containing a complete line read
1372     * from the file starting at the current position */
1373    static char *
1374    readline(FILE *f)
1375    {
1376            char *buffer = NULL;
1377            int buffer_size = 0;
1378            int pos = 0;
1379    
1380            do {
1381                    int c;
1382    
1383                    /* Read a character from the stream */
1384                    c = fgetc(f);
1385    
1386                    /* Is that EOF or new line ? */
1387                    if(c == EOF || c == '\n')
1388                            break;
1389    
1390                    /* Do we have to update buffer ? */
1391                    if(pos >= buffer_size - 1) {
1392                            buffer_size += BUF_SZ;
1393                            buffer = (char*)realloc(buffer, buffer_size);
1394                            if (buffer == NULL)
1395                                    return(NULL);
1396                    }
1397    
1398                    buffer[pos] = c;
1399                    pos++;
1400            } while(1);
1401    
1402            /* Read \n or EOF */
1403            if (buffer == NULL) {
1404                    /* EOF, so we reached the end of the file, return NULL */
1405                    if(feof(f))
1406                            return(NULL);
1407    
1408                    /* Just an empty line with just a newline, allocate a 1 byte buffer to
1409                     * store a zero length string */
1410                    buffer = (char*)malloc(1);
1411                    if(buffer == NULL)
1412                            return(NULL);
1413            }
1414    
1415            /* Zero terminated string */
1416            buffer[pos] = '\0';
1417    
1418            return(buffer);
1419    }
1420    
1421    /* This function returns a pointer to the first non space char in the given
1422     * string */
1423    static char *
1424    skipspaces(char *string)
1425    {
1426            const char spaces[] =
1427                    {
1428                            ' ','\t','\0'
1429                    };
1430            const char *spacechar = spaces;
1431    
1432            if (string == NULL) return(NULL);
1433    
1434            while (*string != '\0') {
1435                    /* Test against space chars */
1436                    while (*spacechar != '\0') {
1437                            if (*string == *spacechar) {
1438                                    string++;
1439                                    spacechar = spaces;
1440                                    break;
1441                            }
1442                            spacechar++;
1443                    }
1444    
1445                    /* No space char */
1446                    if (*spacechar == '\0') return(string);
1447            }
1448    
1449            return(string);
1450    }
1451    
1452    /* This function returns a boolean that tells if the string is only a
1453     * comment */
1454    static int
1455    iscomment(char *string)
1456    {
1457            const char comments[] =
1458                    {
1459                            '#',';', '%', '\0'
1460                    };
1461            const char *cmtchar = comments;
1462            int iscomment = 0;
1463    
1464            if (string == NULL) return(1);
1465    
1466            string = skipspaces(string);
1467    
1468            while(*cmtchar != '\0') {
1469                    if(*string == *cmtchar) {
1470                            iscomment = 1;
1471                            break;
1472                    }
1473                    cmtchar++;
1474            }
1475    
1476            return(iscomment);
1477    }
1478    
1479    #if 0
1480    static void
1481    stats_print(rc_2pass2_t * rc)
1482    {
1483            int i;
1484            const char frame_type[4] = { 'i', 'p', 'b', 's'};
1485    
1486            for (i=0; i<rc->num_frames; i++) {
1487                    twopass_stat_t *s = &rc->stats[i];
1488                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- frame:%d type:%c quant:%d stats:%d scaled:%d desired:%d actual:%d overflow(%c):%.2f\n",
1489                                    i, frame_type[s->type-1], -1, s->length, s->scaled_length,
1490                                    s->desired_length, -1, frame_type[s->type-1], -1.0f);
1491            }
1492    }
1493    #endif
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