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revision 1.1, Tue Mar 25 10:58:33 2003 UTC revision 1.1.2.24, Sun Nov 9 20:49:21 2003 UTC
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1    /******************************************************************************
2     *
3     *  XviD Bit Rate Controller Library
4     *  - VBR 2 pass bitrate controller implementation -
5     *
6     *  Copyright (C)      2002 Foxer <email?>
7     *                     2002 Dirk Knop <dknop@gwdg.de>
8     *                2002-2003 Edouard Gomez <ed.gomez@free.fr>
9     *                     2003 Pete Ross <pross@xvid.org>
10     *
11     *  This curve treatment algorithm is the one originally implemented by Foxer
12     *  and tuned by Dirk Knop for the XviD vfw frontend.
13     *
14     *  This program is free software; you can redistribute it and/or modify
15     *  it under the terms of the GNU General Public License as published by
16     *  the Free Software Foundation; either version 2 of the License, or
17     *  (at your option) any later version.
18     *
19     *  This program is distributed in the hope that it will be useful,
20     *  but WITHOUT ANY WARRANTY; without even the implied warranty of
21     *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22     *  GNU General Public License for more details.
23     *
24     *  You should have received a copy of the GNU General Public License
25     *  along with this program; if not, write to the Free Software
26     *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
27     *
28     * $Id$
29     *
30     *****************************************************************************/
31    
32    #undef COMPENSATE_FORMULA
33    
34    #include <stdio.h>
35    #include <math.h>
36    #include <limits.h>
37    
38    #include "../xvid.h"
39    #include "../image/image.h"
40    
41    /*****************************************************************************
42     * Some constants
43     ****************************************************************************/
44    
45    #define DEFAULT_KEYFRAME_BOOST 0
46    #define DEFAULT_OVERFLOW_CONTROL_STRENGTH 10
47    #define DEFAULT_CURVE_COMPRESSION_HIGH 0
48    #define DEFAULT_CURVE_COMPRESSION_LOW 0
49    #define DEFAULT_MAX_OVERFLOW_IMPROVEMENT 60
50    #define DEFAULT_MAX_OVERFLOW_DEGRADATION 60
51    
52    /* Keyframe settings */
53    #define DEFAULT_KFREDUCTION 20
54    #define DEFAULT_MIN_KEY_INTERVAL 1
55    
56    /*****************************************************************************
57     * Structures
58     ****************************************************************************/
59    
60    /* Statistics */
61    typedef struct {
62            int type;               /* first pass type */
63            int quant;              /* first pass quant */
64            int quant2;             /* Second pass quant */
65            int blks[3];                    /* k,m,y blks */
66            int length;             /* first pass length */
67            int scaled_length;      /* scaled length */
68            int desired_length;     /* desired length; calculated during encoding */
69            int error;
70    
71            int zone_mode;   /* XVID_ZONE_xxx */
72            double weight;
73    } twopass_stat_t;
74    
75    /* Context struct */
76    typedef struct
77    {
78            xvid_plugin_2pass2_t param;
79    
80            /*----------------------------------
81             * constant statistical data
82             *--------------------------------*/
83    
84            /* Number of frames of the sequence */
85            int num_frames;
86    
87            /* Number of Intra frames of the sequence */
88            int num_keyframes;
89    
90            /* Target filesize to reach */
91            uint64_t target;
92    
93            /* Count of each frame types */
94            int count[3];
95    
96            /* Total length of each frame types (1st pass) */
97            uint64_t tot_length[3];
98    
99            /* Average length of each frame types (used first for 1st pass data and
100             * then for scaled averages */
101            double avg_length[3];
102    
103            /* Minimum frame length allowed for each frame type */
104            int min_length[3];
105    
106            /* Total bytes per frame type once the curve has been scaled
107             * NB: advanced parameters do not change this value. This field
108             *     represents the total scaled w/o any advanced settings */
109            uint64_t tot_scaled_length[3];
110    
111            /* Maximum observed frame size observed during the first pass, the RC
112             * will try tp force all frame sizes in the second pass to be under that
113             * limit */
114            int max_length;
115    
116            /*----------------------------------
117             * Zones statistical data
118             *
119             * ToDo: Fix zones, current
120             *       implementation is buggy
121             *--------------------------------*/
122    
123            /* Average weight of the zones */
124            double avg_weight;
125    
126            /* Total length used by XVID_ZONE_QUANT zones */
127            int64_t tot_quant;
128    
129            /*----------------------------------
130             * Advanced settings helper ratios
131             *--------------------------------*/
132    
133            /* This the ratio that has to be applied to all p/b frames in order
134             * to reserve/retrieve bits for/from keyframe boosting and consecutive
135             * keyframe penalty */
136            double pb_iboost_tax_ratio;
137    
138            /* This the ratio to apply to all b/p frames in order to respect the
139             * assymetric curve compression while respecting a target filesize
140             * NB: The assymetric delta gain has to be computed before this ratio
141             *     is applied, and then the delta is added to the scaled size */
142            double assymetric_tax_ratio;
143    
144            /*----------------------------------
145             * Data from the stats file kept
146             * into RAM for easy access
147             *--------------------------------*/
148    
149            /* Array of keyframe locations
150             * eg: rc->keyframe_locations[100] returns the frame number of the 100th
151             *     keyframe */
152            int *keyframe_locations;
153    
154            /* Index of the last keyframe used in the keyframe_location */
155            int KF_idx;
156    
157            /* Array of all 1st pass data file -- see the twopass_stat_t structure
158             * definition for more details */
159            twopass_stat_t * stats;
160    
161            /*----------------------------------
162             * Histerysis helpers
163             *--------------------------------*/
164    
165            /* This field holds the int2float conversion errors of each quant per
166             * frame type, this allow the RC to keep track of rouding error and thus
167             * increase or decrease the chosen quant according to this residue */
168            double quant_error[3][32];
169    
170            /* This fields stores the count of each quant usage per frame type
171             * No real role but for debugging */
172            int quant_count[3][32];
173    
174            /* Last valid quantizer used per frame type, it allows quantizer
175             * increament/decreament limitation in order to avoid big image quality
176             * "jumps" */
177            int last_quant[3];
178    
179            /*----------------------------------
180             * Overflow control
181             *--------------------------------*/
182    
183            /* Current overflow that has to be distributed to p/b frames */
184            double overflow;
185    
186            /* Total overflow for keyframes -- not distributed directly */
187            double KFoverflow;
188    
189            /* Amount of keyframe overflow to introduce to the global p/b frame
190             * overflow counter at each encoded frame */
191            double KFoverflow_partial;
192    
193            /* Unknown ???
194             * ToDo: description */
195            double fq_error;
196    
197            /*----------------------------------
198             * Debug
199             *--------------------------------*/
200            double desired_total;
201            double real_total;
202    } rc_2pass2_t;
203    
204    
205    /*****************************************************************************
206     * Sub plugin functions prototypes
207     ****************************************************************************/
208    
209    static int rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t ** handle);
210    static int rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data);
211    static int rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data);
212    static int rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy);
213    
214    /*****************************************************************************
215     * Plugin definition
216     ****************************************************************************/
217    
218    int
219    xvid_plugin_2pass2(void * handle, int opt, void * param1, void * param2)
220    {
221            switch(opt) {
222            case XVID_PLG_INFO :
223                    return 0;
224    
225            case XVID_PLG_CREATE :
226                    return rc_2pass2_create((xvid_plg_create_t*)param1, param2);
227    
228            case XVID_PLG_DESTROY :
229                    return rc_2pass2_destroy((rc_2pass2_t*)handle, (xvid_plg_destroy_t*)param1);
230    
231            case XVID_PLG_BEFORE :
232                    return rc_2pass2_before((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
233    
234            case XVID_PLG_AFTER :
235                    return rc_2pass2_after((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
236            }
237    
238            return XVID_ERR_FAIL;
239    }
240    
241    /*****************************************************************************
242     * Sub plugin functions definitions
243     ****************************************************************************/
244    
245    /* First a few local helping function prototypes */
246    static  int statsfile_count_frames(rc_2pass2_t * rc, char * filename);
247    static  int statsfile_load(rc_2pass2_t *rc, char * filename);
248    static void zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create);
249    static void first_pass_stats_prepare_data(rc_2pass2_t * rc);
250    static void first_pass_scale_curve_internal(rc_2pass2_t *rc);
251    static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);
252    #if 0
253    static void stats_print(rc_2pass2_t * rc);
254    #endif
255    
256    /*----------------------------------------------------------------------------
257     *--------------------------------------------------------------------------*/
258    
259    static int
260    rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t **handle)
261    {
262            xvid_plugin_2pass2_t * param = (xvid_plugin_2pass2_t *)create->param;
263            rc_2pass2_t * rc;
264            int i;
265    
266            rc = malloc(sizeof(rc_2pass2_t));
267            if (rc == NULL)
268                    return XVID_ERR_MEMORY;
269    
270            rc->param = *param;
271    
272            /* Initialize all defaults */
273    #define _INIT(a, b) if((a) <= 0) (a) = (b)
274            /* Let's set our defaults if needed */
275            _INIT(rc->param.keyframe_boost, DEFAULT_KEYFRAME_BOOST);
276            _INIT(rc->param.overflow_control_strength, DEFAULT_OVERFLOW_CONTROL_STRENGTH);
277            _INIT(rc->param.curve_compression_high, DEFAULT_CURVE_COMPRESSION_HIGH);
278            _INIT(rc->param.curve_compression_low, DEFAULT_CURVE_COMPRESSION_LOW);
279            _INIT(rc->param.max_overflow_improvement, DEFAULT_MAX_OVERFLOW_IMPROVEMENT);
280            _INIT(rc->param.max_overflow_degradation,  DEFAULT_MAX_OVERFLOW_DEGRADATION);
281    
282            /* Keyframe settings */
283            _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);
284            _INIT(rc->param.min_key_interval, DEFAULT_MIN_KEY_INTERVAL);
285    #undef _INIT
286    
287            /* Initialize some stuff to zero */
288            for(i=0; i<3; i++) {
289                    int j;
290                    for (j=0; j<32; j++) {
291                            rc->quant_error[i][j] = 0;
292                            rc->quant_count[i][j] = 0;
293                    }
294            }
295    
296            for (i=0; i<3; i++) rc->last_quant[i] = 0;
297    
298            rc->fq_error = 0;
299    
300            /* Count frames (and intra frames) in the stats file, store the result into
301             * the rc structure */
302            if (statsfile_count_frames(rc, param->filename) == -1) {
303                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
304                    free(rc);
305                    return(XVID_ERR_FAIL);
306            }
307    
308            /* Allocate the stats' memory */
309            if ((rc->stats = malloc(rc->num_frames * sizeof(twopass_stat_t))) == NULL) {
310                    free(rc);
311                    return(XVID_ERR_MEMORY);
312            }
313    
314            /* Allocate keyframes location's memory
315             * PS: see comment in pre_process0 for the +1 location requirement */
316            rc->keyframe_locations = malloc((rc->num_keyframes + 1) * sizeof(int));
317            if (rc->keyframe_locations == NULL) {
318                    free(rc->stats);
319                    free(rc);
320                    return(XVID_ERR_MEMORY);
321            }
322    
323            /* Load the first pass stats */
324            if (statsfile_load(rc, param->filename) == -1) {
325                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
326                    free(rc->keyframe_locations);
327                    free(rc->stats);
328                    free(rc);
329                    return XVID_ERR_FAIL;
330            }
331    
332            /* Compute the target filesize */
333            if (rc->param.bitrate<0) {
334                    /* if negative, bitrate equals the target (in kbytes) */
335                    rc->target = (-rc->param.bitrate) * 1024;
336            } else if (rc->num_frames  < create->fbase/create->fincr) {
337                    /* Source sequence is less than 1s long, we do as if it was 1s long */
338                    rc->target = rc->param.bitrate / 8;
339            } else {
340                    /* Target filesize = bitrate/8 * numframes / framerate */
341                    rc->target =
342                            ((uint64_t)rc->param.bitrate * (uint64_t)rc->num_frames * \
343                             (uint64_t)create->fincr) / \
344                            ((uint64_t)create->fbase * 8);
345            }
346    
347            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Frame rate: %d/%d (%ffps)\n",
348                            create->fbase, create->fincr,
349                            (double)create->fbase/(double)create->fincr);
350            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Number of frames: %d\n", rc->num_frames);
351            if(rc->param.bitrate>=0)
352                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target bitrate: %ld\n", rc->param.bitrate);
353            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target filesize: %lld\n", rc->target);
354    
355            /* Compensate the average frame overhead caused by the container */
356            rc->target -= rc->num_frames*rc->param.container_frame_overhead;
357            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Container Frame overhead: %d\n", rc->param.container_frame_overhead);
358            if(rc->param.container_frame_overhead)
359                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- New target filesize after container compensation: %lld\n", rc->target);
360    
361            /* Gathers some information about first pass stats:
362             *  - finds the minimum frame length for each frame type during 1st pass.
363             *     rc->min_size[]
364             *  - determines the maximum frame length observed (no frame type distinction).
365             *     rc->max_size
366             *  - count how many times each frame type has been used.
367             *     rc->count[]
368             *  - total bytes used per frame type
369             *     rc->total[]
370             *  - store keyframe location
371             *     rc->keyframe_locations[]
372             */
373            first_pass_stats_prepare_data(rc);
374    
375            /* When bitrate is not given it means it has been scaled by an external
376             * application */
377            if (rc->param.bitrate) {
378                    /* Apply zone settings */
379                    zone_process(rc, create);
380                    /* Perform internal curve scaling */
381                    first_pass_scale_curve_internal(rc);
382            } else {
383                    /* External scaling -- zones are ignored */
384                    for (i=0;i<rc->num_frames;i++) {
385                            rc->stats[i].zone_mode = XVID_ZONE_WEIGHT;
386                            rc->stats[i].weight = 1.0;
387                    }
388                    rc->avg_weight = 1.0;
389                    rc->tot_quant = 0;
390            }
391    
392            /* Apply advanced curve options, and compute some parameters in order to
393             * shape the curve in the BEFORE/AFTER pair of functions */
394            scaled_curve_apply_advanced_parameters(rc);
395    
396            *handle = rc;
397            return(0);
398    }
399    
400    /*----------------------------------------------------------------------------
401     *--------------------------------------------------------------------------*/
402    
403    static int
404    rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy)
405    {
406            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- target_total:%lld desired_total:%.2f (%.2f%%) actual_total:%.2f (%.2f%%)\n",
407                            rc->target,
408                            rc->desired_total,
409                            100*rc->desired_total/(double)rc->target,
410                            rc->real_total,
411                            100*rc->real_total/(double)rc->target);
412    
413            free(rc->keyframe_locations);
414            free(rc->stats);
415            free(rc);
416            return(0);
417    }
418    
419    /*----------------------------------------------------------------------------
420     *--------------------------------------------------------------------------*/
421    
422    static int
423    rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data)
424    {
425            twopass_stat_t * s = &rc->stats[data->frame_num];
426            double dbytes;
427            double scaled_quant;
428            double overflow;
429            int capped_to_max_framesize = 0;
430    
431            /* This function is quite long but easy to understand. In order to simplify
432             * the code path (a bit), we treat 3 cases that can return immediatly. */
433    
434            /* First case: Another plugin has already set a quantizer */
435            if (data->quant > 0)
436                    return(0);
437    
438            /* Second case: We are in a Quant zone */
439            if (s->zone_mode == XVID_ZONE_QUANT) {
440                    rc->fq_error += s->weight;
441                    data->quant = (int)rc->fq_error;
442                    rc->fq_error -= data->quant;
443    
444                    s->desired_length = s->length;
445    
446                    return(0);
447            }
448    
449            /* Third case: insufficent stats data */
450            if (data->frame_num >= rc->num_frames)
451                    return(0);
452    
453            /*************************************************************************/
454            /*************************************************************************/
455            /*************************************************************************/
456    
457            /*-------------------------------------------------------------------------
458             * Frame bit allocation first part
459             *
460             * First steps apply user settings, just like it is done in the theoritical
461             * scaled_curve_apply_advanced_parameters
462             *-----------------------------------------------------------------------*/
463    
464            /* Set desired to what we are wanting to obtain for this frame */
465            dbytes = (double)s->scaled_length;
466    
467            /* IFrame user settings*/
468            if (s->type == XVID_TYPE_IVOP) {
469    
470                    /* Keyframe boosting -- All keyframes benefit from it */
471                    dbytes += dbytes*rc->param.keyframe_boost / 100;
472    
473                    /* Applies keyframe penalties, but not the first frame */
474                    if (rc->KF_idx) {
475                            int penalty_distance;
476    
477                            /* Minimum keyframe distance penalties */
478                            penalty_distance  = rc->param.min_key_interval;
479                            penalty_distance -= rc->keyframe_locations[rc->KF_idx];
480                            penalty_distance += rc->keyframe_locations[rc->KF_idx-1];
481    
482                            /* Ah ah ! guilty keyframe, you're under arrest ! */
483                            if (penalty_distance > 0)
484                                    dbytes -= dbytes*penalty_distance*rc->param.kfreduction/100;
485                    }
486            } else {
487    
488                    /* P/S/B frames must reserve some bits for iframe boosting */
489                    dbytes *= rc->pb_iboost_tax_ratio;
490    
491                    /* Apply assymetric curve compression */
492                    if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
493                            double assymetric_delta;
494    
495                            /* Compute the assymetric delta, this is computed before applying
496                             * the tax, as done in the pre_process function */
497                            if (dbytes > rc->avg_length[s->type-1])
498                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_high / 100.0;
499                            else
500                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_low  / 100.0;
501    
502                            /* Now we must apply the assymetric tax, else our curve compression
503                             * would not give a theoritical target size equal to what it is
504                             * expected */
505                            dbytes *= rc->assymetric_tax_ratio;
506    
507                            /* Now we can add the assymetric delta */
508                            dbytes += assymetric_delta;
509                    }
510            }
511    
512            /* That is what we would like to have -- Don't put that chunk after
513             * overflow control, otherwise, overflow is counted twice and you obtain
514             * half sized bitrate sequences */
515            s->desired_length  = (int)dbytes;
516            rc->desired_total += dbytes;
517    
518            /*------------------------------------------------------------------------
519             * Frame bit allocation: overflow control part.
520             *
521             * Unlike the theoritical scaled_curve_apply_advanced_parameters, here
522             * it's real encoding and we need to make sure we don't go so far from
523             * what is our ideal scaled curve.
524             *-----------------------------------------------------------------------*/
525    
526            /* Compute the overflow we should compensate */
527            if (s->type != XVID_TYPE_IVOP) {
528                    double frametype_factor;
529                    double framesize_factor;
530    
531                    /* Take only the desired part of overflow */
532                    overflow = rc->overflow;
533    
534                    /* Factor that will take care to decrease the overflow applied
535                     * according to the importance of this frame type in term of
536                     * overall size */
537                    frametype_factor  = rc->count[XVID_TYPE_IVOP-1]*rc->avg_length[XVID_TYPE_IVOP-1];
538                    frametype_factor += rc->count[XVID_TYPE_PVOP-1]*rc->avg_length[XVID_TYPE_PVOP-1];
539                    frametype_factor += rc->count[XVID_TYPE_BVOP-1]*rc->avg_length[XVID_TYPE_BVOP-1];
540                    frametype_factor /= rc->count[s->type-1]*rc->avg_length[s->type-1];
541                    frametype_factor  = 1/frametype_factor;
542    
543                    /* Factor that will take care not to compensate too much for this frame
544                     * size */
545                    framesize_factor  = dbytes;
546                    framesize_factor /= rc->avg_length[s->type-1];
547    
548                    /* Treat only the overflow part concerned by this frame type and size */
549                    overflow *= frametype_factor;
550    #if 0
551                    /* Leave this one alone, as it impacts badly on quality */
552                    overflow *= framesize_factor;
553    #endif
554    
555                    /* Apply the overflow strength imposed by the user */
556                    overflow *= (rc->param.overflow_control_strength/100.0f);
557            } else {
558                    /* no overflow applied in IFrames because:
559                     *  - their role is important as they're references for P/BFrames.
560                     *  - there aren't much in typical sequences, so if an IFrame overflows too
561                     *    much, this overflow may impact the next IFrame too much and generate
562                     *    a sequence of poor quality frames */
563                    overflow = 0;
564            }
565    
566            /* Make sure we are not trying to compensate more overflow than we even have */
567            if (fabs(overflow) > fabs(rc->overflow))
568                    overflow = rc->overflow;
569    
570            /* Make sure the overflow doesn't make the frame size to get out of the range
571             * [-max_degradation..+max_improvment] */
572            if (overflow > dbytes*rc->param.max_overflow_improvement / 100) {
573                    if(overflow <= dbytes)
574                            dbytes += dbytes * rc->param.max_overflow_improvement / 100;
575                    else
576                            dbytes += overflow * rc->param.max_overflow_improvement / 100;
577            } else if (overflow < - dbytes * rc->param.max_overflow_degradation / 100) {
578                    dbytes -= dbytes * rc->param.max_overflow_degradation / 100;
579            } else {
580                    dbytes += overflow;
581            }
582    
583            /*-------------------------------------------------------------------------
584             * Frame bit allocation last part:
585             *
586             * Cap frame length so we don't reach neither bigger frame sizes than first
587             * pass nor smaller than the allowed minimum.
588             *-----------------------------------------------------------------------*/
589    
590            if (dbytes > s->length) {
591                    dbytes = s->length;
592            } else if (dbytes < rc->min_length[s->type-1]) {
593                    dbytes = rc->min_length[s->type-1];
594            } else if (dbytes > rc->max_length) {
595                    /* ToDo: this condition is always wrong as max_length == maximum frame
596                     * length of first pass, so the first condition already caps the frame
597                     * size... */
598                    capped_to_max_framesize = 1;
599                    dbytes = rc->max_length;
600                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- frame:%d Capped to maximum frame size\n",
601                                    data->frame_num);
602            }
603    
604            /*------------------------------------------------------------------------
605             * Desired frame length <-> quantizer mapping
606             *-----------------------------------------------------------------------*/
607    
608            /* For bframes we must retrieve the original quant used (sent to xvidcore)
609             * as core applies the bquant formula before writing the stat log entry */
610            if(s->type == XVID_TYPE_BVOP) {
611    
612                    twopass_stat_t *b_ref = s;
613    
614                    /* Find the reference frame */
615                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
616                            b_ref--;
617    
618                    /* Compute the original quant */
619                    s->quant  = 100*s->quant - data->bquant_offset;
620                    s->quant += data->bquant_ratio - 1; /* to avoid rouding issues */
621                    s->quant  = s->quant/data->bquant_ratio - b_ref->quant;
622            }
623    
624            /* Don't laugh at this very 'simple' quant<->filesize relationship, it
625             * proves to be acurate enough for our algorithm */
626            scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;
627    
628    #ifdef COMPENSATE_FORMULA
629            /* We know xvidcore will apply the bframe formula again, so we compensate
630             * it right now to make sure we would not apply it twice */
631            if(s->type == XVID_TYPE_BVOP) {
632    
633                    twopass_stat_t *b_ref = s;
634    
635                    /* Find the reference frame */
636                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
637                            b_ref--;
638    
639                    /* Compute the quant it would be if the core did not apply the bframe
640                     * formula */
641                    scaled_quant  = 100*scaled_quant - data->bquant_offset;
642                    scaled_quant += data->bquant_ratio - 1; /* to avoid rouding issues */
643                    scaled_quant /= data->bquant_ratio;
644            }
645    #endif
646    
647            /* Quantizer has been scaled using floating point operations/results, we
648             * must cast it to integer */
649            data->quant = (int)scaled_quant;
650    
651            /* Let's clip the computed quantizer, if needed */
652            if (data->quant < 1) {
653                    data->quant = 1;
654            } else if (data->quant > 31) {
655                    data->quant = 31;
656            } else {
657    
658                    /* The frame quantizer has not been clipped, this appears to be a good
659                     * computed quantizer, do not loose quantizer decimal part that we
660                     * accumulate for later reuse when its sum represents a complete
661                     * unit. */
662                    rc->quant_error[s->type-1][data->quant] += scaled_quant - (double)data->quant;
663    
664                    if (rc->quant_error[s->type-1][data->quant] >= 1.0) {
665                            rc->quant_error[s->type-1][data->quant] -= 1.0;
666                            data->quant++;
667                    } else if (rc->quant_error[s->type-1][data->quant] <= -1.0) {
668                            rc->quant_error[s->type-1][data->quant] += 1.0;
669                            data->quant--;
670                    }
671            }
672    
673            /* Now we have a computed quant that is in the right quante range, with a
674             * possible +1 correction due to cumulated error. We can now safely clip
675             * the quantizer again with user's quant ranges. "Safely" means the Rate
676             * Control could learn more about this quantizer, this knowledge is useful
677             * for future frames even if it this quantizer won't be really used atm,
678             * that's why we don't perform this clipping earlier. */
679            if (data->quant < data->min_quant[s->type-1]) {
680                    data->quant = data->min_quant[s->type-1];
681            } else if (data->quant > data->max_quant[s->type-1]) {
682                    data->quant = data->max_quant[s->type-1];
683            }
684    
685            /* To avoid big quality jumps from frame to frame, we apply a "security"
686             * rule that makes |last_quant - new_quant| <= 2. This rule only applies
687             * to predicted frames (P and B) */
688            if (s->type != XVID_TYPE_IVOP && rc->last_quant[s->type-1] && capped_to_max_framesize == 0) {
689    
690                    if (data->quant > rc->last_quant[s->type-1] + 2) {
691                            data->quant = rc->last_quant[s->type-1] + 2;
692                            DPRINTF(XVID_DEBUG_RC,
693                                            "[xvid rc] -- frame %d p/b-frame quantizer prevented from rising too steeply\n",
694                                            data->frame_num);
695                    }
696                    if (data->quant < rc->last_quant[s->type-1] - 2) {
697                            data->quant = rc->last_quant[s->type-1] - 2;
698                            DPRINTF(XVID_DEBUG_RC,
699                                            "[xvid rc] -- frame:%d p/b-frame quantizer prevented from falling too steeply\n",
700                                            data->frame_num);
701                    }
702            }
703    
704            /* We don't want to pollute the RC histerisis when our computed quant has
705             * been computed from a capped frame size */
706            if (capped_to_max_framesize == 0)
707                    rc->last_quant[s->type-1] = data->quant;
708    
709            /* Don't forget to force 1st pass frame type ;-) */
710            data->type = s->type;
711    
712            /* Store the quantizer into the statistics -- Used to compensate the double
713             * formula symptom */
714            s->quant2 = data->quant;
715    
716            return 0;
717    }
718    
719    /*----------------------------------------------------------------------------
720     *--------------------------------------------------------------------------*/
721    
722    static int
723    rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data)
724    {
725            const char frame_type[4] = { 'i', 'p', 'b', 's'};
726            twopass_stat_t * s = &rc->stats[data->frame_num];
727    
728            /* Insufficent stats data */
729            if (data->frame_num >= rc->num_frames)
730                    return 0;
731    
732            /* Update the quantizer counter */
733            rc->quant_count[s->type-1][data->quant]++;
734    
735            /* Update the frame type overflow */
736            if (data->type == XVID_TYPE_IVOP) {
737                    int kfdiff = 0;
738    
739                    if(rc->KF_idx != rc->num_frames -1) {
740                            kfdiff  = rc->keyframe_locations[rc->KF_idx+1];
741                            kfdiff -= rc->keyframe_locations[rc->KF_idx];
742                    }
743    
744                    /* Flush Keyframe overflow accumulator */
745                    rc->overflow += rc->KFoverflow;
746    
747                    /* Store the frame overflow to the keyframe accumulator */
748                    rc->KFoverflow = s->desired_length - data->length;
749    
750                    if (kfdiff > 1) {
751                            /* Non-consecutive keyframes case:
752                             * We can then divide this total keyframe overflow into equal parts
753                             * that we will distribute into regular overflow at each frame
754                             * between the sequence bounded by two IFrames */
755                            rc->KFoverflow_partial = rc->KFoverflow / (kfdiff - 1);
756                    } else {
757                            /* Consecutive keyframes case:
758                             * Flush immediatly the keyframe overflow and reset keyframe
759                             * overflow */
760                            rc->overflow += rc->KFoverflow;
761                            rc->KFoverflow = 0;
762                            rc->KFoverflow_partial = 0;
763                    }
764                    rc->KF_idx++;
765            } else {
766                    /* Accumulate the frame overflow */
767                    rc->overflow += s->desired_length - data->length;
768    
769                    /* Distribute part of the keyframe overflow */
770                    rc->overflow += rc->KFoverflow_partial;
771    
772                    /* Don't forget to substract that same amount from the total keyframe
773                     * overflow */
774                    rc->KFoverflow -= rc->KFoverflow_partial;
775            }
776    
777            rc->overflow += s->error = s->desired_length - data->length;
778            rc->real_total += data->length;
779    
780            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",
781                            data->frame_num,
782                            frame_type[data->type-1],
783                            data->quant,
784                            s->length,
785                            s->scaled_length,
786                            s->desired_length,
787                            s->desired_length - s->error,
788                            -s->error,
789                            rc->overflow);
790    
791            return(0);
792    }
793    
794    /*****************************************************************************
795     * Helper functions definition
796     ****************************************************************************/
797    
798    /* Default buffer size for reading lines */
799    #define BUF_SZ   1024
800    
801    /* Helper functions for reading/parsing the stats file */
802    static char *skipspaces(char *string);
803    static int iscomment(char *string);
804    static char *readline(FILE *f);
805    
806    /* This function counts the number of frame entries in the stats file
807     * It also counts the number of I Frames */
808    static int
809    statsfile_count_frames(rc_2pass2_t * rc, char * filename)
810    {
811            FILE * f;
812            char *line;
813            int lines;
814    
815            rc->num_frames = 0;
816            rc->num_keyframes = 0;
817    
818            if ((f = fopen(filename, "rb")) == NULL)
819                    return(-1);
820    
821            lines = 0;
822            while ((line = readline(f)) != NULL) {
823    
824                    char *ptr;
825                    char type;
826                    int fields, nouse;
827    
828                    lines++;
829    
830                    /* We skip spaces */
831                    ptr = skipspaces(line);
832    
833                    /* Skip coment lines */
834                    if(iscomment(ptr)) {
835                            free(line);
836                            continue;
837                    }
838    
839                    /* Read the stat line from buffer */
840                    fields = sscanf(ptr,
841                                                    "%c %d %d %d %d %d",
842                                                    &type, &nouse, &nouse, &nouse, &nouse, &nouse);
843    
844                    /* Valid stats files have at least 6 fields */
845                    if (fields == 6) {
846                            switch(type) {
847                            case 'i':
848                            case 'I':
849                                    rc->num_keyframes++;
850                            case 'p':
851                            case 'P':
852                            case 'b':
853                            case 'B':
854                            case 's':
855                            case 'S':
856                                    rc->num_frames++;
857                                    break;
858                            default:
859                                    DPRINTF(XVID_DEBUG_RC,
860                                                    "[xvid rc] -- WARNING: L%d unknown frame type used (%c).\n",
861                                                    lines, type);
862                            }
863                    } else {
864                                    DPRINTF(XVID_DEBUG_RC,
865                                                    "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",
866                                                    lines, 6-fields);
867                    }
868    
869                    /* Free the line buffer */
870                    free(line);
871            }
872    
873            /* We are done with the file */
874            fclose(f);
875    
876            return(0);
877    }
878    
879    /* open stats file(s) and read into rc->stats array */
880    static int
881    statsfile_load(rc_2pass2_t *rc, char * filename)
882    {
883            FILE * f;
884            int processed_entries;
885    
886            /* Opens the file */
887            if ((f = fopen(filename, "rb"))==NULL)
888                    return(-1);
889    
890            processed_entries = 0;
891            while(processed_entries < rc->num_frames) {
892                    char type;
893                    int fields;
894                    twopass_stat_t * s = &rc->stats[processed_entries];
895                    char *line, *ptr;
896    
897                    /* Read the line from the file */
898                    if((line = readline(f)) == NULL)
899                            break;
900    
901                    /* We skip spaces */
902                    ptr = skipspaces(line);
903    
904                    /* Skip comment lines */
905                    if(iscomment(ptr)) {
906                            free(line);
907                            continue;
908                    }
909    
910                    /* Reset this field that is optional */
911                    s->scaled_length = 0;
912    
913                    /* Convert the fields */
914                    fields = sscanf(ptr,
915                                                    "%c %d %d %d %d %d %d\n",
916                                                    &type,
917                                                    &s->quant,
918                                                    &s->blks[0], &s->blks[1], &s->blks[2],
919                                                    &s->length,
920                                                    &s->scaled_length);
921    
922                    /* Free line buffer, we don't need it anymore */
923                    free(line);
924    
925                    /* Fail silently, this has probably been warned in
926                     * statsfile_count_frames */
927                    if(fields != 6 && fields != 7)
928                            continue;
929    
930                    /* Convert frame type */
931                    switch(type) {
932                    case 'i':
933                    case 'I':
934                            s->type = XVID_TYPE_IVOP;
935                            break;
936                    case 'p':
937                    case 'P':
938                    case 's':
939                    case 'S':
940                            s->type = XVID_TYPE_PVOP;
941                            break;
942                    case 'b':
943                    case 'B':
944                            s->type = XVID_TYPE_BVOP;
945                            break;
946                    default:
947                            /* Same as before, fail silently */
948                            continue;
949                    }
950    
951                    /* Ok it seems it's been processed correctly */
952                    processed_entries++;
953            }
954    
955            /* Close the file */
956            fclose(f);
957    
958            return(0);
959    }
960    
961    /* pre-process the statistics data
962     * - for each type, count, tot_length, min_length, max_length
963     * - set keyframes_locations */
964    static void
965    first_pass_stats_prepare_data(rc_2pass2_t * rc)
966    {
967            int i,j;
968    
969            /* *rc fields initialization
970             * NB: INT_MAX and INT_MIN are used in order to be immediately replaced
971             *     with real values of the 1pass */
972            for (i=0; i<3; i++) {
973                    rc->count[i]=0;
974                    rc->tot_length[i] = 0;
975                    rc->min_length[i] = INT_MAX;
976            }
977    
978            rc->max_length = INT_MIN;
979    
980            /* Loop through all frames and find/compute all the stuff this function
981             * is supposed to do */
982            for (i=j=0; i<rc->num_frames; i++) {
983                    twopass_stat_t * s = &rc->stats[i];
984    
985                    rc->count[s->type-1]++;
986                    rc->tot_length[s->type-1] += s->length;
987    
988                    if (s->length < rc->min_length[s->type-1]) {
989                            rc->min_length[s->type-1] = s->length;
990                    }
991    
992                    if (s->length > rc->max_length) {
993                            rc->max_length = s->length;
994                    }
995    
996                    if (s->type == XVID_TYPE_IVOP) {
997                            rc->keyframe_locations[j] = i;
998                            j++;
999                    }
1000            }
1001    
1002            /* NB:
1003             * The "per sequence" overflow system considers a natural sequence to be
1004             * formed by all frames between two iframes, so if we want to make sure
1005             * the system does not go nuts during last sequence, we force the last
1006             * frame to appear in the keyframe locations array. */
1007            rc->keyframe_locations[j] = i;
1008    
1009            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass IFrame length: %d\n", rc->min_length[0]);
1010            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass PFrame length: %d\n", rc->min_length[1]);
1011            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass BFrame length: %d\n", rc->min_length[2]);
1012    }
1013    
1014    /* calculate zone weight "center" */
1015    static void
1016    zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create)
1017    {
1018            int i,j;
1019            int n = 0;
1020    
1021            rc->avg_weight = 0.0;
1022            rc->tot_quant = 0;
1023    
1024    
1025            if (create->num_zones == 0) {
1026                    for (j = 0; j < rc->num_frames; j++) {
1027                            rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1028                            rc->stats[j].weight = 1.0;
1029                    }
1030                    rc->avg_weight += rc->num_frames * 1.0;
1031                    n += rc->num_frames;
1032            }
1033    
1034    
1035            for(i=0; i < create->num_zones; i++) {
1036    
1037                    int next = (i+1<create->num_zones) ? create->zones[i+1].frame : rc->num_frames;
1038    
1039                    if (i==0 && create->zones[i].frame > 0) {
1040                            for (j = 0; j < create->zones[i].frame && j < rc->num_frames; j++) {
1041                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1042                                    rc->stats[j].weight = 1.0;
1043                            }
1044                            rc->avg_weight += create->zones[i].frame * 1.0;
1045                            n += create->zones[i].frame;
1046                    }
1047    
1048                    if (create->zones[i].mode == XVID_ZONE_WEIGHT) {
1049                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1050                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1051                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1052                            }
1053                            next -= create->zones[i].frame;
1054                            rc->avg_weight += (double)(next * create->zones[i].increment) / (double)create->zones[i].base;
1055                            n += next;
1056                    }else{  /* XVID_ZONE_QUANT */
1057                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1058                                    rc->stats[j].zone_mode = XVID_ZONE_QUANT;
1059                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1060                                    rc->tot_quant += rc->stats[j].length;
1061                            }
1062                    }
1063            }
1064            rc->avg_weight = n>0 ? rc->avg_weight/n : 1.0;
1065    
1066            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- center_weight:%f (for %d frames)  fixed_bytes:%d\n", rc->avg_weight, n, rc->tot_quant);
1067    }
1068    
1069    
1070    /* scale the curve */
1071    static void
1072    first_pass_scale_curve_internal(rc_2pass2_t *rc)
1073    {
1074            int64_t target;
1075            int64_t pass1_length;
1076            double scaler;
1077            int i, num_MBs;
1078    
1079            /* We remove the bytes used by the fixed quantizer zones
1080             * ToDo: this approach is flawed, the same amount of bytes is removed from
1081             *       target and first pass data, this has no sense, zone_process should
1082             *       give us two results one for unscaled data (1pass) and the other
1083             *       one for scaled data and we should then write:
1084             *       target = rc->target - rc->tot_quant_scaled;
1085             *       pass1_length = rc->i+p+b - rc->tot_quant_firstpass */
1086            target = rc->target - rc->tot_quant;
1087    
1088            /* Do the same for the first pass data */
1089            pass1_length  = rc->tot_length[XVID_TYPE_IVOP-1];
1090            pass1_length += rc->tot_length[XVID_TYPE_PVOP-1];
1091            pass1_length += rc->tot_length[XVID_TYPE_BVOP-1];
1092            pass1_length -= rc->tot_quant;
1093    
1094            /* Let's compute a linear scaler in order to perform curve scaling */
1095            scaler = (double)target / (double)pass1_length;
1096    
1097            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1098                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected before correction\n");
1099                    scaler = 1.0;
1100            }
1101    
1102            /* Compute min frame lengths (for each frame type) according to the number
1103             * of MBs. We sum all block type counters of frame 0, this gives us the
1104             * number of MBs.
1105             *
1106             * We compare these hardcoded values with observed values in first pass
1107             * (determined in pre_process0).Then we keep the real minimum. */
1108    
1109            /* Number of MBs */
1110            num_MBs  = rc->stats[0].blks[0];
1111            num_MBs += rc->stats[0].blks[1];
1112            num_MBs += rc->stats[0].blks[2];
1113    
1114            /* Minimum for I frames */
1115            if(rc->min_length[XVID_TYPE_IVOP-1] > ((num_MBs*22) + 240) / 8)
1116                    rc->min_length[XVID_TYPE_IVOP-1] = ((num_MBs*22) + 240) / 8;
1117    
1118            /* Minimum for P/S frames */
1119            if(rc->min_length[XVID_TYPE_PVOP-1] > ((num_MBs) + 88)  / 8)
1120                    rc->min_length[XVID_TYPE_PVOP-1] = ((num_MBs) + 88)  / 8;
1121    
1122            /* Minimum for B frames */
1123            if(rc->min_length[XVID_TYPE_BVOP-1] > 8)
1124                    rc->min_length[XVID_TYPE_BVOP-1] = 8;
1125    
1126            /* Perform an initial scale pass.
1127             *
1128             * If a frame size is scaled underneath our hardcoded minimums, then we
1129             * force the frame size to the minimum, and deduct the original & scaled
1130             * frame length from the original and target total lengths */
1131            for (i=0; i<rc->num_frames; i++) {
1132                    twopass_stat_t * s = &rc->stats[i];
1133                    int len;
1134    
1135                    /* No need to scale frame length for which a specific quantizer is
1136                     * specified thanks to zones */
1137                    if (s->zone_mode == XVID_ZONE_QUANT) {
1138                            s->scaled_length = s->length;
1139                            continue;
1140                    }
1141    
1142                    /* Compute the scaled length */
1143                    len = (int)((double)s->length * scaler * s->weight / rc->avg_weight);
1144    
1145                    /* Compare with the computed minimum */
1146                    if (len < rc->min_length[s->type-1]) {
1147                            /* This is a 'forced size' frame, set its frame size to the
1148                             * computed minimum */
1149                            s->scaled_length = rc->min_length[s->type-1];
1150    
1151                            /* Remove both scaled and original size from their respective
1152                             * total counters, as we prepare a second pass for 'regular'
1153                             * frames */
1154                            target -= s->scaled_length;
1155                            pass1_length -= s->length;
1156                    } else {
1157                            /* Do nothing for now, we'll scale this later */
1158                            s->scaled_length = 0;
1159                    }
1160            }
1161    
1162            /* The first pass on data substracted all 'forced size' frames from the
1163             * total counters. Now, it's possible to scale the 'regular' frames. */
1164    
1165            /* Scaling factor for 'regular' frames */
1166            scaler = (double)target / (double)pass1_length;
1167    
1168            /* Detect undersizing */
1169            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1170                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected after correction\n");
1171                    scaler = 1.0;
1172            }
1173    
1174            /* Do another pass with the new scaler */
1175            for (i=0; i<rc->num_frames; i++) {
1176                    twopass_stat_t * s = &rc->stats[i];
1177    
1178                    /* Ignore frame with forced frame sizes */
1179                    if (s->scaled_length == 0)
1180                            s->scaled_length = (int)((double)s->length * scaler * s->weight / rc->avg_weight);
1181            }
1182    
1183            /* Job done */
1184            return;
1185    }
1186    
1187    /* Apply all user settings to the scaled curve
1188     * This implies:
1189     *   keyframe boosting
1190     *   high/low compression */
1191    static void
1192    scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)
1193    {
1194            int i;
1195            uint64_t ivop_boost_total;
1196    
1197            /* Reset the rate controller (per frame type) total byte counters */
1198            for (i=0; i<3; i++) rc->tot_scaled_length[i] = 0;
1199    
1200            /* Compute total bytes for each frame type */
1201            for (i=0; i<rc->num_frames;i++) {
1202                    twopass_stat_t *s = &rc->stats[i];
1203                    rc->tot_scaled_length[s->type-1] += s->scaled_length;
1204            }
1205    
1206            /* First we compute the total amount of bits needed, as being described by
1207             * the scaled distribution. During this pass over the complete stats data,
1208             * we see how much bits two user settings will get/give from/to p&b frames:
1209             *  - keyframe boosting
1210             *  - keyframe distance penalty */
1211            rc->KF_idx = 0;
1212            ivop_boost_total = 0;
1213            for (i=0; i<rc->num_frames; i++) {
1214                    twopass_stat_t * s = &rc->stats[i];
1215    
1216                    /* Some more work is needed for I frames */
1217                    if (s->type == XVID_TYPE_IVOP) {
1218                            int penalty_distance;
1219                            int ivop_boost;
1220    
1221                            /* Accumulate bytes needed for keyframe boosting */
1222                            ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;
1223    
1224                            if (rc->KF_idx) {
1225                                    /* Minimum keyframe distance penalties */
1226                                    penalty_distance  = rc->param.min_key_interval;
1227                                    penalty_distance -= rc->keyframe_locations[rc->KF_idx];
1228                                    penalty_distance += rc->keyframe_locations[rc->KF_idx-1];
1229    
1230                                    /* Ah ah ! guilty keyframe, you're under arrest ! */
1231                                    if (penalty_distance > 0)
1232                                             ivop_boost -= (s->scaled_length + ivop_boost)*penalty_distance*rc->param.kfreduction/100;
1233                            }
1234    
1235                            /* If the frame size drops under the minimum length, then cap ivop_boost */
1236                            if (ivop_boost + s->scaled_length < rc->min_length[XVID_TYPE_IVOP-1])
1237                                    ivop_boost = rc->min_length[XVID_TYPE_IVOP-1] - s->scaled_length;
1238    
1239                            /* Accumulate the ivop boost */
1240                            ivop_boost_total += ivop_boost;
1241    
1242                            /* Don't forget to update the keyframe index */
1243                            rc->KF_idx++;
1244                    }
1245            }
1246    
1247            /* Initialize the IBoost tax ratio for P/S/B frames
1248             *
1249             * This ratio has to be applied to p/b/s frames in order to reserve
1250             * additional bits for keyframes (keyframe boosting) or if too much
1251             * keyframe distance is applied, bits retrieved from the keyframes.
1252             *
1253             * ie pb_length *= rc->pb_iboost_tax_ratio;
1254             *
1255             *    gives the ideal length of a p/b frame */
1256    
1257            /* Compute the total length of p/b/s frames (temporary storage into
1258             * movie_curve) */
1259            rc->pb_iboost_tax_ratio  = (double)rc->tot_scaled_length[XVID_TYPE_PVOP-1];
1260            rc->pb_iboost_tax_ratio += (double)rc->tot_scaled_length[XVID_TYPE_BVOP-1];
1261    
1262            /* Compute the ratio described above
1263             *     taxed_total = sum(0, n, tax*scaled_length)
1264             * <=> taxed_total = tax.sum(0, n, tax*scaled_length)
1265             * <=> tax = taxed_total / original_total */
1266            rc->pb_iboost_tax_ratio =
1267                    (rc->pb_iboost_tax_ratio - ivop_boost_total) /
1268                    rc->pb_iboost_tax_ratio;
1269    
1270            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- IFrame boost tax ratio:%.2f\n",
1271                            rc->pb_iboost_tax_ratio);
1272    
1273            /* Compute the average size of frames per frame type */
1274            for(i=0; i<3; i++) {
1275                    /* Special case for missing type or weird case */
1276                    if (rc->count[i] == 0 || rc->pb_iboost_tax_ratio == 0) {
1277                            rc->avg_length[i] = 1;
1278                    } else {
1279                            rc->avg_length[i] = rc->tot_scaled_length[i];
1280    
1281                            if (i == XVID_TYPE_IVOP) {
1282                                    /* I Frames total has to be added the boost total */
1283                                    rc->avg_length[i] += ivop_boost_total;
1284                            } else {
1285                                    /* P/B frames has to taxed */
1286                                    rc->avg_length[i] *= rc->pb_iboost_tax_ratio;
1287                            }
1288    
1289                            /* Finally compute the average frame size */
1290                            rc->avg_length[i] /= (double)rc->count[i];
1291                    }
1292            }
1293    
1294            /* Assymetric curve compression */
1295            if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
1296                    double symetric_total;
1297                    double assymetric_delta_total;
1298    
1299                    /* Like I frame boosting, assymetric curve compression modifies the total
1300                     * amount of needed bits, we must compute the ratio so we can prescale
1301                     lengths */
1302                    symetric_total = 0;
1303                    assymetric_delta_total = 0;
1304                    for (i=0; i<rc->num_frames; i++) {
1305                            double assymetric_delta;
1306                            double dbytes;
1307                            twopass_stat_t * s = &rc->stats[i];
1308    
1309                            /* I Frames are not concerned by assymetric scaling */
1310                            if (s->type == XVID_TYPE_IVOP)
1311                                    continue;
1312    
1313                            /* During the real run, we would have to apply the iboost tax */
1314                            dbytes = s->scaled_length * rc->pb_iboost_tax_ratio;
1315    
1316                            /* Update the symmetric curve compression total */
1317                            symetric_total += dbytes;
1318    
1319                            /* Apply assymetric curve compression */
1320                            if (dbytes > rc->avg_length[s->type-1])
1321                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_high / 100.0f;
1322                            else
1323                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_low  / 100.0f;
1324    
1325                            /* Cap to the minimum frame size if needed */
1326                            if (dbytes + assymetric_delta < rc->min_length[s->type-1])
1327                                    assymetric_delta = rc->min_length[s->type-1] - dbytes;
1328    
1329                            /* Accumulate after assymetric curve compression */
1330                            assymetric_delta_total += assymetric_delta;
1331                    }
1332    
1333                    /* Compute the tax that all p/b frames have to pay in order to respect the
1334                     * bit distribution changes that the assymetric compression curve imposes
1335                     * We want assymetric_total = sum(0, n-1, tax.scaled_length)
1336                     *      ie assymetric_total = ratio.sum(0, n-1, scaled_length)
1337                     *         ratio = assymetric_total / symmetric_total */
1338                    rc->assymetric_tax_ratio = ((double)symetric_total - (double)assymetric_delta_total) / (double)symetric_total;
1339            } else {
1340                    rc->assymetric_tax_ratio = 1.0f;
1341            }
1342    
1343            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Assymetric tax ratio:%.2f\n", rc->assymetric_tax_ratio);
1344    
1345            /* Last bits that need to be reset */
1346            rc->overflow = 0;
1347            rc->KFoverflow = 0;
1348            rc->KFoverflow_partial = 0;
1349            rc->KF_idx = 0;
1350            rc->desired_total = 0;
1351            rc->real_total = 0;
1352    
1353            /* Job done */
1354            return;
1355    }
1356    
1357    /*****************************************************************************
1358     * Still more low level stuff (nothing to do with stats treatment)
1359     ****************************************************************************/
1360    
1361    /* This function returns an allocated string containing a complete line read
1362     * from the file starting at the current position */
1363    static char *
1364    readline(FILE *f)
1365    {
1366            char *buffer = NULL;
1367            int buffer_size = 0;
1368            int pos = 0;
1369    
1370            do {
1371                    int c;
1372    
1373                    /* Read a character from the stream */
1374                    c = fgetc(f);
1375    
1376                    /* Is that EOF or new line ? */
1377                    if(c == EOF || c == '\n')
1378                            break;
1379    
1380                    /* Do we have to update buffer ? */
1381                    if(pos >= buffer_size - 1) {
1382                            buffer_size += BUF_SZ;
1383                            buffer = (char*)realloc(buffer, buffer_size);
1384                            if (buffer == NULL)
1385                                    return(NULL);
1386                    }
1387    
1388                    buffer[pos] = c;
1389                    pos++;
1390            } while(1);
1391    
1392            /* Read \n or EOF */
1393            if (buffer == NULL) {
1394                    /* EOF, so we reached the end of the file, return NULL */
1395                    if(feof(f))
1396                            return(NULL);
1397    
1398                    /* Just an empty line with just a newline, allocate a 1 byte buffer to
1399                     * store a zero length string */
1400                    buffer = (char*)malloc(1);
1401                    if(buffer == NULL)
1402                            return(NULL);
1403            }
1404    
1405            /* Zero terminated string */
1406            buffer[pos] = '\0';
1407    
1408            return(buffer);
1409    }
1410    
1411    /* This function returns a pointer to the first non space char in the given
1412     * string */
1413    static char *
1414    skipspaces(char *string)
1415    {
1416            const char spaces[] =
1417                    {
1418                            ' ','\t','\0'
1419                    };
1420            const char *spacechar = spaces;
1421    
1422            if (string == NULL) return(NULL);
1423    
1424            while (*string != '\0') {
1425                    /* Test against space chars */
1426                    while (*spacechar != '\0') {
1427                            if (*string == *spacechar) {
1428                                    string++;
1429                                    spacechar = spaces;
1430                                    break;
1431                            }
1432                            spacechar++;
1433                    }
1434    
1435                    /* No space char */
1436                    if (*spacechar == '\0') return(string);
1437            }
1438    
1439            return(string);
1440    }
1441    
1442    /* This function returns a boolean that tells if the string is only a
1443     * comment */
1444    static int
1445    iscomment(char *string)
1446    {
1447            const char comments[] =
1448                    {
1449                            '#',';', '%', '\0'
1450                    };
1451            const char *cmtchar = comments;
1452            int iscomment = 0;
1453    
1454            if (string == NULL) return(1);
1455    
1456            string = skipspaces(string);
1457    
1458            while(*cmtchar != '\0') {
1459                    if(*string == *cmtchar) {
1460                            iscomment = 1;
1461                            break;
1462                    }
1463                    cmtchar++;
1464            }
1465    
1466            return(iscomment);
1467    }
1468    
1469    #if 0
1470    static void
1471    stats_print(rc_2pass2_t * rc)
1472    {
1473            int i;
1474            const char frame_type[4] = { 'i', 'p', 'b', 's'};
1475    
1476            for (i=0; i<rc->num_frames; i++) {
1477                    twopass_stat_t *s = &rc->stats[i];
1478                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- frame:%d type:%c quant:%d stats:%d scaled:%d desired:%d actual:%d overflow(%c):%.2f\n",
1479                                    i, frame_type[s->type-1], -1, s->length, s->scaled_length,
1480                                    s->desired_length, -1, frame_type[s->type-1], -1.0f);
1481            }
1482    }
1483    #endif
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