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revision 1.1, Tue Mar 25 10:58:33 2003 UTC revision 1.1.2.32, Sun Dec 21 12:41:48 2003 UTC
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1    /******************************************************************************
2     *
3     *  XviD Bit Rate Controller Library
4     *  - VBR 2 pass bitrate controller implementation -
5     *
6     *  Copyright (C)      2002 Foxer <email?>
7     *                     2002 Dirk Knop <dknop@gwdg.de>
8     *                2002-2003 Edouard Gomez <ed.gomez@free.fr>
9     *                     2003 Pete Ross <pross@xvid.org>
10     *
11     *  This curve treatment algorithm is the one originally implemented by Foxer
12     *  and tuned by Dirk Knop for the XviD vfw frontend.
13     *
14     *  This program is free software; you can redistribute it and/or modify
15     *  it under the terms of the GNU General Public License as published by
16     *  the Free Software Foundation; either version 2 of the License, or
17     *  (at your option) any later version.
18     *
19     *  This program is distributed in the hope that it will be useful,
20     *  but WITHOUT ANY WARRANTY; without even the implied warranty of
21     *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22     *  GNU General Public License for more details.
23     *
24     *  You should have received a copy of the GNU General Public License
25     *  along with this program; if not, write to the Free Software
26     *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
27     *
28     * $Id$
29     *
30     *****************************************************************************/
31    
32    #define BQUANT_PRESCALE
33    #undef COMPENSATE_FORMULA
34    
35    /* forces second pass not to be bigger than first */
36    #undef PASS_SMALLER
37    
38    #include <stdio.h>
39    #include <math.h>
40    #include <limits.h>
41    
42    #include "../xvid.h"
43    #include "../image/image.h"
44    
45    /*****************************************************************************
46     * Some default settings
47     ****************************************************************************/
48    
49    #define DEFAULT_KEYFRAME_BOOST 0
50    #define DEFAULT_OVERFLOW_CONTROL_STRENGTH 10
51    #define DEFAULT_CURVE_COMPRESSION_HIGH 0
52    #define DEFAULT_CURVE_COMPRESSION_LOW 0
53    #define DEFAULT_MAX_OVERFLOW_IMPROVEMENT 10
54    #define DEFAULT_MAX_OVERFLOW_DEGRADATION 10
55    
56    /* Keyframe settings */
57    #define DEFAULT_KFREDUCTION 20
58    #define DEFAULT_KFTHRESHOLD 1
59    
60    /*****************************************************************************
61     * Some default constants (can be tuned)
62     ****************************************************************************/
63    
64    /* Specify the invariant part of the headers bits (header+MV)
65     * as  hlength/cst */
66    #define INVARIANT_HEADER_PART_IVOP 1 /* factor 1.0f   */
67    #define INVARIANT_HEADER_PART_PVOP 2 /* factor 0.5f   */
68    #define INVARIANT_HEADER_PART_BVOP 8 /* factor 0.125f */
69    
70    /*****************************************************************************
71     * Structures
72     ****************************************************************************/
73    
74    /* Statistics */
75    typedef struct {
76            int type;               /* first pass type */
77            int quant;              /* first pass quant */
78            int blks[3];            /* k,m,y blks */
79            int length;             /* first pass length */
80            int invariant;          /* what we assume as being invariant between the two passes, it's a sub part of header + MV bits */
81            int scaled_length;      /* scaled length */
82            int desired_length;     /* desired length; calculated during encoding */
83            int error;
84    
85            int zone_mode;   /* XVID_ZONE_xxx */
86            double weight;
87    } twopass_stat_t;
88    
89    /* Context struct */
90    typedef struct
91    {
92            xvid_plugin_2pass2_t param;
93    
94            /*----------------------------------
95             * constant statistical data
96             *--------------------------------*/
97    
98            /* Number of frames of the sequence */
99            int num_frames;
100    
101            /* Number of Intra frames of the sequence */
102            int num_keyframes;
103    
104            /* Target filesize to reach */
105            uint64_t target;
106    
107            /* Count of each frame types */
108            int count[3];
109    
110            /* Total length of each frame types (1st pass) */
111            uint64_t tot_length[3];
112            uint64_t tot_invariant[3];
113    
114            /* Average length of each frame types (used first for 1st pass data and
115             * then for scaled averages */
116            double avg_length[3];
117    
118            /* Minimum frame length allowed for each frame type */
119            int min_length[3];
120    
121            /* Total bytes per frame type once the curve has been scaled
122             * NB: advanced parameters do not change this value. This field
123             *     represents the total scaled w/o any advanced settings */
124            uint64_t tot_scaled_length[3];
125    
126            /* Maximum observed frame size observed during the first pass, the RC
127             * will try tp force all frame sizes in the second pass to be under that
128             * limit */
129            int max_length;
130    
131            /*----------------------------------
132             * Zones statistical data
133             *
134             * ToDo: Fix zones, current
135             *       implementation is buggy
136             *--------------------------------*/
137    
138            /* Average weight of the zones */
139            double avg_weight;
140    
141            /* Total length used by XVID_ZONE_QUANT zones */
142            uint64_t tot_quant;
143            uint64_t tot_quant_invariant;
144    
145            /*----------------------------------
146             * Advanced settings helper ratios
147             *--------------------------------*/
148    
149            /* This the ratio that has to be applied to all p/b frames in order
150             * to reserve/retrieve bits for/from keyframe boosting and consecutive
151             * keyframe penalty */
152            double pb_iboost_tax_ratio;
153    
154            /* This the ratio to apply to all b/p frames in order to respect the
155             * assymetric curve compression while respecting a target filesize
156             * NB: The assymetric delta gain has to be computed before this ratio
157             *     is applied, and then the delta is added to the scaled size */
158            double assymetric_tax_ratio;
159    
160            /*----------------------------------
161             * Data from the stats file kept
162             * into RAM for easy access
163             *--------------------------------*/
164    
165            /* Array of keyframe locations
166             * eg: rc->keyframe_locations[100] returns the frame number of the 100th
167             *     keyframe */
168            int *keyframe_locations;
169    
170            /* Index of the last keyframe used in the keyframe_location */
171            int KF_idx;
172    
173            /* Array of all 1st pass data file -- see the twopass_stat_t structure
174             * definition for more details */
175            twopass_stat_t * stats;
176    
177            /*----------------------------------
178             * Histerysis helpers
179             *--------------------------------*/
180    
181            /* This field holds the int2float conversion errors of each quant per
182             * frame type, this allow the RC to keep track of rouding error and thus
183             * increase or decrease the chosen quant according to this residue */
184            double quant_error[3][32];
185    
186            /* This fields stores the count of each quant usage per frame type
187             * No real role but for debugging */
188            int quant_count[3][32];
189    
190            /* Last valid quantizer used per frame type, it allows quantizer
191             * increament/decreament limitation in order to avoid big image quality
192             * "jumps" */
193            int last_quant[3];
194    
195            /*----------------------------------
196             * Overflow control
197             *--------------------------------*/
198    
199            /* Current overflow that has to be distributed to p/b frames */
200            double overflow;
201    
202            /* Total overflow for keyframes -- not distributed directly */
203            double KFoverflow;
204    
205            /* Amount of keyframe overflow to introduce to the global p/b frame
206             * overflow counter at each encoded frame */
207            double KFoverflow_partial;
208    
209            /* Unknown ???
210             * ToDo: description */
211            double fq_error;
212    
213            /*----------------------------------
214             * Debug
215             *--------------------------------*/
216            double desired_total;
217            double real_total;
218    } rc_2pass2_t;
219    
220    
221    /*****************************************************************************
222     * Sub plugin functions prototypes
223     ****************************************************************************/
224    
225    static int rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t ** handle);
226    static int rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data);
227    static int rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data);
228    static int rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy);
229    
230    /*****************************************************************************
231     * Plugin definition
232     ****************************************************************************/
233    
234    int
235    xvid_plugin_2pass2(void * handle, int opt, void * param1, void * param2)
236    {
237            switch(opt) {
238            case XVID_PLG_INFO :
239            case XVID_PLG_FRAME :
240                    return 0;
241    
242            case XVID_PLG_CREATE :
243                    return rc_2pass2_create((xvid_plg_create_t*)param1, param2);
244    
245            case XVID_PLG_DESTROY :
246                    return rc_2pass2_destroy((rc_2pass2_t*)handle, (xvid_plg_destroy_t*)param1);
247    
248            case XVID_PLG_BEFORE :
249                    return rc_2pass2_before((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
250    
251            case XVID_PLG_AFTER :
252                    return rc_2pass2_after((rc_2pass2_t*)handle, (xvid_plg_data_t*)param1);
253            }
254    
255            return XVID_ERR_FAIL;
256    }
257    
258    /*****************************************************************************
259     * Sub plugin functions definitions
260     ****************************************************************************/
261    
262    /* First a few local helping function prototypes */
263    static  int statsfile_count_frames(rc_2pass2_t * rc, char * filename);
264    static  int statsfile_load(rc_2pass2_t *rc, char * filename);
265    static void zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create);
266    static void first_pass_stats_prepare_data(rc_2pass2_t * rc);
267    static void first_pass_scale_curve_internal(rc_2pass2_t *rc);
268    static void scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc);
269    #if 0
270    static void stats_print(rc_2pass2_t * rc);
271    #endif
272    
273    /*----------------------------------------------------------------------------
274     *--------------------------------------------------------------------------*/
275    
276    static int
277    rc_2pass2_create(xvid_plg_create_t * create, rc_2pass2_t **handle)
278    {
279            xvid_plugin_2pass2_t * param = (xvid_plugin_2pass2_t *)create->param;
280            rc_2pass2_t * rc;
281            int i;
282    
283            rc = malloc(sizeof(rc_2pass2_t));
284            if (rc == NULL)
285                    return XVID_ERR_MEMORY;
286    
287            rc->param = *param;
288    
289            /* Initialize all defaults */
290    #define _INIT(a, b) if((a) <= 0) (a) = (b)
291            /* Let's set our defaults if needed */
292            _INIT(rc->param.keyframe_boost, DEFAULT_KEYFRAME_BOOST);
293            _INIT(rc->param.overflow_control_strength, DEFAULT_OVERFLOW_CONTROL_STRENGTH);
294            _INIT(rc->param.curve_compression_high, DEFAULT_CURVE_COMPRESSION_HIGH);
295            _INIT(rc->param.curve_compression_low, DEFAULT_CURVE_COMPRESSION_LOW);
296            _INIT(rc->param.max_overflow_improvement, DEFAULT_MAX_OVERFLOW_IMPROVEMENT);
297            _INIT(rc->param.max_overflow_degradation,  DEFAULT_MAX_OVERFLOW_DEGRADATION);
298    
299            /* Keyframe settings */
300            _INIT(rc->param.kfreduction, DEFAULT_KFREDUCTION);
301            _INIT(rc->param.kfthreshold, DEFAULT_KFTHRESHOLD);
302    #undef _INIT
303    
304            /* Initialize some stuff to zero */
305            for(i=0; i<3; i++) {
306                    int j;
307                    for (j=0; j<32; j++) {
308                            rc->quant_error[i][j] = 0;
309                            rc->quant_count[i][j] = 0;
310                    }
311            }
312    
313            for (i=0; i<3; i++) rc->last_quant[i] = 0;
314    
315            rc->fq_error = 0;
316    
317            /* Count frames (and intra frames) in the stats file, store the result into
318             * the rc structure */
319            if (statsfile_count_frames(rc, param->filename) == -1) {
320                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
321                    free(rc);
322                    return(XVID_ERR_FAIL);
323            }
324    
325            /* Allocate the stats' memory */
326            if ((rc->stats = malloc(rc->num_frames * sizeof(twopass_stat_t))) == NULL) {
327                    free(rc);
328                    return(XVID_ERR_MEMORY);
329            }
330    
331            /* Allocate keyframes location's memory
332             * PS: see comment in pre_process0 for the +1 location requirement */
333            rc->keyframe_locations = malloc((rc->num_keyframes + 1) * sizeof(int));
334            if (rc->keyframe_locations == NULL) {
335                    free(rc->stats);
336                    free(rc);
337                    return(XVID_ERR_MEMORY);
338            }
339    
340            /* Load the first pass stats */
341            if (statsfile_load(rc, param->filename) == -1) {
342                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- ERROR: fopen %s failed\n", param->filename);
343                    free(rc->keyframe_locations);
344                    free(rc->stats);
345                    free(rc);
346                    return XVID_ERR_FAIL;
347            }
348    
349            /* Compute the target filesize */
350            if (rc->param.bitrate<0) {
351                    /* if negative, bitrate equals the target (in kbytes) */
352                    rc->target = ((uint64_t)(-rc->param.bitrate)) * 1024;
353            } else if (rc->num_frames  < create->fbase/create->fincr) {
354                    /* Source sequence is less than 1s long, we do as if it was 1s long */
355                    rc->target = rc->param.bitrate / 8;
356            } else {
357                    /* Target filesize = bitrate/8 * numframes / framerate */
358                    rc->target =
359                            ((uint64_t)rc->param.bitrate * (uint64_t)rc->num_frames * \
360                             (uint64_t)create->fincr) / \
361                            ((uint64_t)create->fbase * 8);
362            }
363    
364            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Frame rate: %d/%d (%ffps)\n",
365                            create->fbase, create->fincr,
366                            (double)create->fbase/(double)create->fincr);
367            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Number of frames: %d\n", rc->num_frames);
368            if(rc->param.bitrate>=0)
369                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target bitrate: %ld\n", rc->param.bitrate);
370            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Target filesize: %lld\n", rc->target);
371    
372            /* Compensate the average frame overhead caused by the container */
373            rc->target -= rc->num_frames*rc->param.container_frame_overhead;
374            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Container Frame overhead: %d\n", rc->param.container_frame_overhead);
375            if(rc->param.container_frame_overhead)
376                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- New target filesize after container compensation: %lld\n", rc->target);
377    
378            /* Gathers some information about first pass stats:
379             *  - finds the minimum frame length for each frame type during 1st pass.
380             *     rc->min_size[]
381             *  - determines the maximum frame length observed (no frame type distinction).
382             *     rc->max_size
383             *  - count how many times each frame type has been used.
384             *     rc->count[]
385             *  - total bytes used per frame type
386             *     rc->tot_length[]
387             *  - total bytes considered invariant between the 2 passes
388             *  - store keyframe location
389             *     rc->keyframe_locations[]
390             */
391            first_pass_stats_prepare_data(rc);
392    
393            /* When bitrate is not given it means it has been scaled by an external
394             * application */
395            if (rc->param.bitrate) {
396                    /* Apply zone settings
397                     * - set rc->tot_quant which represents the total num of bytes spent in
398                     *   fixed quant zones
399                     * - set rc->tot_quant_invariant which represents the total num of bytes spent
400                     *   in fixed quant zones for headers */
401                    zone_process(rc, create);
402                    /* Perform internal curve scaling */
403                    first_pass_scale_curve_internal(rc);
404            } else {
405                    /* External scaling -- zones are ignored */
406                    for (i=0;i<rc->num_frames;i++) {
407                            rc->stats[i].zone_mode = XVID_ZONE_WEIGHT;
408                            rc->stats[i].weight = 1.0;
409                    }
410                    rc->avg_weight = 1.0;
411                    rc->tot_quant = 0;
412            }
413    
414            /* Apply advanced curve options, and compute some parameters in order to
415             * shape the curve in the BEFORE/AFTER pair of functions */
416            scaled_curve_apply_advanced_parameters(rc);
417    
418            *handle = rc;
419            return(0);
420    }
421    
422    /*----------------------------------------------------------------------------
423     *--------------------------------------------------------------------------*/
424    
425    static int
426    rc_2pass2_destroy(rc_2pass2_t * rc, xvid_plg_destroy_t * destroy)
427    {
428            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- target_total:%lld desired_total:%.2f (%.2f%%) actual_total:%.2f (%.2f%%)\n",
429                            rc->target,
430                            rc->desired_total,
431                            100*rc->desired_total/(double)rc->target,
432                            rc->real_total,
433                            100*rc->real_total/(double)rc->target);
434    
435            free(rc->keyframe_locations);
436            free(rc->stats);
437            free(rc);
438            return(0);
439    }
440    
441    /*----------------------------------------------------------------------------
442     *--------------------------------------------------------------------------*/
443    
444    static int
445    rc_2pass2_before(rc_2pass2_t * rc, xvid_plg_data_t * data)
446    {
447            twopass_stat_t * s = &rc->stats[data->frame_num];
448            double dbytes;
449            double scaled_quant;
450            double overflow;
451            int capped_to_max_framesize = 0;
452    
453            /* This function is quite long but easy to understand. In order to simplify
454             * the code path (a bit), we treat 3 cases that can return immediatly. */
455    
456            /* First case: Another plugin has already set a quantizer */
457            if (data->quant > 0)
458                    return(0);
459    
460            /* Second case: insufficent stats data */
461            if (data->frame_num >= rc->num_frames) {
462                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- stats file too short (now processing frame %d)",
463                            data->frame_num);
464                    return(0);
465            }
466    
467            /* Third case: We are in a Quant zone */
468            if (s->zone_mode == XVID_ZONE_QUANT) {
469                    rc->fq_error += s->weight;
470                    data->quant = (int)rc->fq_error;
471                    rc->fq_error -= data->quant;
472    
473                    s->desired_length = s->length;
474    
475                    return(0);
476            }
477    
478    
479            /*************************************************************************/
480            /*************************************************************************/
481            /*************************************************************************/
482    
483            /*-------------------------------------------------------------------------
484             * Frame bit allocation first part
485             *
486             * First steps apply user settings, just like it is done in the theoritical
487             * scaled_curve_apply_advanced_parameters
488             *-----------------------------------------------------------------------*/
489    
490            /* Set desired to what we are wanting to obtain for this frame */
491            dbytes = (double)s->scaled_length;
492    
493            /* IFrame user settings*/
494            if (s->type == XVID_TYPE_IVOP) {
495                    /* Keyframe boosting -- All keyframes benefit from it */
496                    dbytes += dbytes*rc->param.keyframe_boost / 100;
497    
498    #if 0 /* ToDo: decide how to apply kfthresholding */
499    #endif
500            } else {
501    
502                    /* P/S/B frames must reserve some bits for iframe boosting */
503                    dbytes *= rc->pb_iboost_tax_ratio;
504    
505                    /* Apply assymetric curve compression */
506                    if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
507                            double assymetric_delta;
508    
509                            /* Compute the assymetric delta, this is computed before applying
510                             * the tax, as done in the pre_process function */
511                            if (dbytes > rc->avg_length[s->type-1])
512                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_high / 100.0;
513                            else
514                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * rc->param.curve_compression_low  / 100.0;
515    
516                            /* Now we must apply the assymetric tax, else our curve compression
517                             * would not give a theoritical target size equal to what it is
518                             * expected */
519                            dbytes *= rc->assymetric_tax_ratio;
520    
521                            /* Now we can add the assymetric delta */
522                            dbytes += assymetric_delta;
523                    }
524            }
525    
526            /* That is what we would like to have -- Don't put that chunk after
527             * overflow control, otherwise, overflow is counted twice and you obtain
528             * half sized bitrate sequences */
529            s->desired_length  = (int)dbytes;
530            rc->desired_total += dbytes;
531    
532            /*------------------------------------------------------------------------
533             * Frame bit allocation: overflow control part.
534             *
535             * Unlike the theoritical scaled_curve_apply_advanced_parameters, here
536             * it's real encoding and we need to make sure we don't go so far from
537             * what is our ideal scaled curve.
538             *-----------------------------------------------------------------------*/
539    
540            /* Compute the overflow we should compensate */
541            if (s->type != XVID_TYPE_IVOP || rc->overflow > 0) {
542                    double frametype_factor;
543                    double framesize_factor;
544    
545                    /* Take only the desired part of overflow */
546                    overflow = rc->overflow;
547    
548                    /* Factor that will take care to decrease the overflow applied
549                     * according to the importance of this frame type in term of
550                     * overall size */
551                    frametype_factor  = rc->count[XVID_TYPE_IVOP-1]*rc->avg_length[XVID_TYPE_IVOP-1];
552                    frametype_factor += rc->count[XVID_TYPE_PVOP-1]*rc->avg_length[XVID_TYPE_PVOP-1];
553                    frametype_factor += rc->count[XVID_TYPE_BVOP-1]*rc->avg_length[XVID_TYPE_BVOP-1];
554                    frametype_factor /= rc->count[s->type-1]*rc->avg_length[s->type-1];
555                    frametype_factor  = 1/frametype_factor;
556    
557                    /* Factor that will take care not to compensate too much for this frame
558                     * size */
559                    framesize_factor  = dbytes;
560                    framesize_factor /= rc->avg_length[s->type-1];
561    
562                    /* Treat only the overflow part concerned by this frame type and size */
563                    overflow *= frametype_factor;
564    #if 0
565                    /* Leave this one alone, as it impacts badly on quality */
566                    overflow *= framesize_factor;
567    #endif
568    
569                    /* Apply the overflow strength imposed by the user */
570                    overflow *= (rc->param.overflow_control_strength/100.0f);
571            } else {
572                    /* no negative overflow applied in IFrames because:
573                     *  - their role is important as they're references for P/BFrames.
574                     *  - there aren't much in typical sequences, so if an IFrame overflows too
575                     *    much, this overflow may impact the next IFrame too much and generate
576                     *    a sequence of poor quality frames */
577                    overflow = 0;
578            }
579    
580            /* Make sure we are not trying to compensate more overflow than we even have */
581            if (fabs(overflow) > fabs(rc->overflow))
582                    overflow = rc->overflow;
583    
584            /* Make sure the overflow doesn't make the frame size to get out of the range
585             * [-max_degradation..+max_improvment] */
586            if (overflow > dbytes*rc->param.max_overflow_improvement / 100) {
587                    if(overflow <= dbytes)
588                            dbytes += dbytes * rc->param.max_overflow_improvement / 100;
589                    else
590                            dbytes += overflow * rc->param.max_overflow_improvement / 100;
591            } else if (overflow < - dbytes * rc->param.max_overflow_degradation / 100) {
592                    dbytes -= dbytes * rc->param.max_overflow_degradation / 100;
593            } else {
594                    dbytes += overflow;
595            }
596    
597            /*-------------------------------------------------------------------------
598             * Frame bit allocation last part:
599             *
600             * Cap frame length so we don't reach neither bigger frame sizes than first
601             * pass nor smaller than the allowed minimum.
602             *-----------------------------------------------------------------------*/
603    
604    #ifdef PASS_SMALLER
605            if (dbytes > s->length) {
606                    dbytes = s->length;
607            } else
608    #endif
609                    if (dbytes < rc->min_length[s->type-1]) {
610                    dbytes = rc->min_length[s->type-1];
611            } else if (dbytes > rc->max_length) {
612                    /* ToDo: this condition is always wrong as max_length == maximum frame
613                     * length of first pass, so the first condition already caps the frame
614                     * size... */
615                    capped_to_max_framesize = 1;
616                    dbytes = rc->max_length;
617                    DPRINTF(XVID_DEBUG_RC,"[xvid rc] -- frame:%d Capped to maximum frame size\n",
618                                    data->frame_num);
619            }
620    
621            /*------------------------------------------------------------------------
622             * Desired frame length <-> quantizer mapping
623             *-----------------------------------------------------------------------*/
624    
625    #ifdef BQUANT_PRESCALE
626            /* For bframes we prescale the quantizer to avoid too high quant scaling */
627            if(s->type == XVID_TYPE_BVOP) {
628    
629                    twopass_stat_t *b_ref = s;
630    
631                    /* Find the reference frame */
632                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
633                            b_ref--;
634    
635                    /* Compute the original quant */
636                    s->quant  = 2*(100*s->quant - data->bquant_offset);
637                    s->quant += data->bquant_ratio - 1; /* to avoid rounding issues */
638                    s->quant  = s->quant/data->bquant_ratio - b_ref->quant;
639            }
640    #endif
641    
642            /* Don't laugh at this very 'simple' quant<->size relationship, it
643             * proves to be acurate enough for our algorithm */
644            scaled_quant = (double)s->quant*(double)s->length/(double)dbytes;
645    
646    #ifdef COMPENSATE_FORMULA
647            /* We know xvidcore will apply the bframe formula again, so we compensate
648             * it right now to make sure we would not apply it twice */
649            if(s->type == XVID_TYPE_BVOP) {
650    
651                    twopass_stat_t *b_ref = s;
652    
653                    /* Find the reference frame */
654                    while(b_ref != &rc->stats[0] && b_ref->type == XVID_TYPE_BVOP)
655                            b_ref--;
656    
657                    /* Compute the quant it would be if the core did not apply the bframe
658                     * formula */
659                    scaled_quant  = 100*scaled_quant - data->bquant_offset;
660                    scaled_quant += data->bquant_ratio - 1; /* to avoid rouding issues */
661                    scaled_quant /= data->bquant_ratio;
662            }
663    #endif
664    
665            /* Quantizer has been scaled using floating point operations/results, we
666             * must cast it to integer */
667            data->quant = (int)scaled_quant;
668    
669            /* Let's clip the computed quantizer, if needed */
670            if (data->quant < 1) {
671                    data->quant = 1;
672            } else if (data->quant > 31) {
673                    data->quant = 31;
674            } else {
675    
676                    /* The frame quantizer has not been clipped, this appears to be a good
677                     * computed quantizer, do not loose quantizer decimal part that we
678                     * accumulate for later reuse when its sum represents a complete
679                     * unit. */
680                    rc->quant_error[s->type-1][data->quant] += scaled_quant - (double)data->quant;
681    
682                    if (rc->quant_error[s->type-1][data->quant] >= 1.0) {
683                            rc->quant_error[s->type-1][data->quant] -= 1.0;
684                            data->quant++;
685                    } else if (rc->quant_error[s->type-1][data->quant] <= -1.0) {
686                            rc->quant_error[s->type-1][data->quant] += 1.0;
687                            data->quant--;
688                    }
689            }
690    
691            /* Now we have a computed quant that is in the right quante range, with a
692             * possible +1 correction due to cumulated error. We can now safely clip
693             * the quantizer again with user's quant ranges. "Safely" means the Rate
694             * Control could learn more about this quantizer, this knowledge is useful
695             * for future frames even if it this quantizer won't be really used atm,
696             * that's why we don't perform this clipping earlier. */
697            if (data->quant < data->min_quant[s->type-1]) {
698                    data->quant = data->min_quant[s->type-1];
699            } else if (data->quant > data->max_quant[s->type-1]) {
700                    data->quant = data->max_quant[s->type-1];
701            }
702    
703            /* To avoid big quality jumps from frame to frame, we apply a "security"
704             * rule that makes |last_quant - new_quant| <= 2. This rule only applies
705             * to predicted frames (P and B) */
706            if (s->type != XVID_TYPE_IVOP && rc->last_quant[s->type-1] && capped_to_max_framesize == 0) {
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 rising too steeply\n",
712                                            data->frame_num);
713                    }
714                    if (data->quant < rc->last_quant[s->type-1] - 2) {
715                            data->quant = rc->last_quant[s->type-1] - 2;
716                            DPRINTF(XVID_DEBUG_RC,
717                                            "[xvid rc] -- frame:%d p/b-frame quantizer prevented from falling too steeply\n",
718                                            data->frame_num);
719                    }
720            }
721    
722            /* We don't want to pollute the RC histerisis when our computed quant has
723             * been computed from a capped frame size */
724            if (capped_to_max_framesize == 0)
725                    rc->last_quant[s->type-1] = data->quant;
726    
727            /* Don't forget to force 1st pass frame type ;-) */
728            data->type = s->type;
729    
730            return 0;
731    }
732    
733    /*----------------------------------------------------------------------------
734     *--------------------------------------------------------------------------*/
735    
736    static int
737    rc_2pass2_after(rc_2pass2_t * rc, xvid_plg_data_t * data)
738    {
739            const char frame_type[4] = { 'i', 'p', 'b', 's'};
740            twopass_stat_t * s = &rc->stats[data->frame_num];
741    
742            /* Insufficent stats data */
743            if (data->frame_num >= rc->num_frames)
744                    return 0;
745    
746            /* Update the quantizer counter */
747            rc->quant_count[s->type-1][data->quant]++;
748    
749            /* Update the frame type overflow */
750            if (data->type == XVID_TYPE_IVOP) {
751                    int kfdiff = 0;
752    
753                    if(rc->KF_idx != rc->num_frames -1) {
754                            kfdiff  = rc->keyframe_locations[rc->KF_idx+1];
755                            kfdiff -= rc->keyframe_locations[rc->KF_idx];
756                    }
757    
758                    /* Flush Keyframe overflow accumulator */
759                    rc->overflow += rc->KFoverflow;
760    
761                    /* Store the frame overflow to the keyframe accumulator */
762                    rc->KFoverflow = s->desired_length - data->length;
763    
764                    if (kfdiff > 1) {
765                            /* Non-consecutive keyframes case:
766                             * We can then divide this total keyframe overflow into equal parts
767                             * that we will distribute into regular overflow at each frame
768                             * between the sequence bounded by two IFrames */
769                            rc->KFoverflow_partial = rc->KFoverflow / (kfdiff - 1);
770                    } else {
771                            /* Consecutive keyframes case:
772                             * Flush immediatly the keyframe overflow and reset keyframe
773                             * overflow */
774                            rc->overflow += rc->KFoverflow;
775                            rc->KFoverflow = 0;
776                            rc->KFoverflow_partial = 0;
777                    }
778                    rc->KF_idx++;
779            } else {
780                    /* Accumulate the frame overflow */
781                    rc->overflow += s->desired_length - data->length;
782    
783                    /* Distribute part of the keyframe overflow */
784                    rc->overflow += rc->KFoverflow_partial;
785    
786                    /* Don't forget to substract that same amount from the total keyframe
787                     * overflow */
788                    rc->KFoverflow -= rc->KFoverflow_partial;
789            }
790    
791            rc->overflow += (s->error = s->desired_length - data->length);
792            rc->real_total += data->length;
793    
794            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",
795                            data->frame_num,
796                            frame_type[data->type-1],
797                            data->quant,
798                            s->length,
799                            s->scaled_length,
800                            s->desired_length,
801                            s->desired_length - s->error,
802                            -s->error,
803                            rc->overflow);
804    
805            return(0);
806    }
807    
808    /*****************************************************************************
809     * Helper functions definition
810     ****************************************************************************/
811    
812    /* Default buffer size for reading lines */
813    #define BUF_SZ   1024
814    
815    /* Helper functions for reading/parsing the stats file */
816    static char *skipspaces(char *string);
817    static int iscomment(char *string);
818    static char *readline(FILE *f);
819    
820    /* This function counts the number of frame entries in the stats file
821     * It also counts the number of I Frames */
822    static int
823    statsfile_count_frames(rc_2pass2_t * rc, char * filename)
824    {
825            FILE * f;
826            char *line;
827            int lines;
828    
829            rc->num_frames = 0;
830            rc->num_keyframes = 0;
831    
832            if ((f = fopen(filename, "rb")) == NULL)
833                    return(-1);
834    
835            lines = 0;
836            while ((line = readline(f)) != NULL) {
837    
838                    char *ptr;
839                    char type;
840                    int fields;
841    
842                    lines++;
843    
844                    /* We skip spaces */
845                    ptr = skipspaces(line);
846    
847                    /* Skip coment lines or empty lines */
848                    if(iscomment(ptr) || *ptr == '\0') {
849                            free(line);
850                            continue;
851                    }
852    
853                    /* Read the stat line from buffer */
854                    fields = sscanf(ptr, "%c", &type);
855    
856                    /* Valid stats files have at least 7 fields */
857                    if (fields == 1) {
858                            switch(type) {
859                            case 'i':
860                            case 'I':
861                                    rc->num_keyframes++;
862                            case 'p':
863                            case 'P':
864                            case 'b':
865                            case 'B':
866                            case 's':
867                            case 'S':
868                                    rc->num_frames++;
869                                    break;
870                            default:
871                                    DPRINTF(XVID_DEBUG_RC,
872                                                    "[xvid rc] -- WARNING: L%d unknown frame type used (%c).\n",
873                                                    lines, type);
874                            }
875                    } else {
876                                    DPRINTF(XVID_DEBUG_RC,
877                                                    "[xvid rc] -- WARNING: L%d misses some stat fields (%d).\n",
878                                                    lines, 7-fields);
879                    }
880    
881                    /* Free the line buffer */
882                    free(line);
883            }
884    
885            /* We are done with the file */
886            fclose(f);
887    
888            return(0);
889    }
890    
891    /* open stats file(s) and read into rc->stats array */
892    static int
893    statsfile_load(rc_2pass2_t *rc, char * filename)
894    {
895            FILE * f;
896            int processed_entries;
897    
898            /* Opens the file */
899            if ((f = fopen(filename, "rb"))==NULL)
900                    return(-1);
901    
902            processed_entries = 0;
903            while(processed_entries < rc->num_frames) {
904                    char type;
905                    int fields;
906                    twopass_stat_t * s = &rc->stats[processed_entries];
907                    char *line, *ptr;
908    
909                    /* Read the line from the file */
910                    if((line = readline(f)) == NULL)
911                            break;
912    
913                    /* We skip spaces */
914                    ptr = skipspaces(line);
915    
916                    /* Skip comment lines or empty lines */
917                    if(iscomment(ptr) || *ptr == '\0') {
918                            free(line);
919                            continue;
920                    }
921    
922                    /* Reset this field that is optional */
923                    s->scaled_length = 0;
924    
925                    /* Convert the fields */
926                    fields = sscanf(ptr,
927                                                    "%c %d %d %d %d %d %d %d\n",
928                                                    &type,
929                                                    &s->quant,
930                                                    &s->blks[0], &s->blks[1], &s->blks[2],
931                                                    &s->length, &s->invariant /* not really yet */,
932                                                    &s->scaled_length);
933    
934                    /* Free line buffer, we don't need it anymore */
935                    free(line);
936    
937                    /* Fail silently, this has probably been warned in
938                     * statsfile_count_frames */
939                    if(fields != 7 && fields != 8)
940                            continue;
941    
942                    /* Convert frame type and compute the invariant length part */
943                    switch(type) {
944                    case 'i':
945                    case 'I':
946                            s->type = XVID_TYPE_IVOP;
947                            s->invariant /= INVARIANT_HEADER_PART_IVOP;
948                            break;
949                    case 'p':
950                    case 'P':
951                    case 's':
952                    case 'S':
953                            s->type = XVID_TYPE_PVOP;
954                            s->invariant /= INVARIANT_HEADER_PART_PVOP;
955                            break;
956                    case 'b':
957                    case 'B':
958                            s->type = XVID_TYPE_BVOP;
959                            s->invariant /= INVARIANT_HEADER_PART_BVOP;
960                            break;
961                    default:
962                            /* Same as before, fail silently */
963                            continue;
964                    }
965    
966                    /* Ok it seems it's been processed correctly */
967                    processed_entries++;
968            }
969    
970            /* Close the file */
971            fclose(f);
972    
973            return(0);
974    }
975    
976    /* pre-process the statistics data
977     * - for each type, count, tot_length, min_length, max_length
978     * - set keyframes_locations */
979    static void
980    first_pass_stats_prepare_data(rc_2pass2_t * rc)
981    {
982            int i,j;
983    
984            /* *rc fields initialization
985             * NB: INT_MAX and INT_MIN are used in order to be immediately replaced
986             *     with real values of the 1pass */
987            for (i=0; i<3; i++) {
988                    rc->count[i]=0;
989                    rc->tot_length[i] = 0;
990                    rc->tot_invariant[i] = 0;
991                    rc->min_length[i] = INT_MAX;
992            }
993    
994            rc->max_length = INT_MIN;
995    
996            /* Loop through all frames and find/compute all the stuff this function
997             * is supposed to do */
998            for (i=j=0; i<rc->num_frames; i++) {
999                    twopass_stat_t * s = &rc->stats[i];
1000    
1001                    rc->count[s->type-1]++;
1002                    rc->tot_length[s->type-1] += s->length;
1003                    rc->tot_invariant[s->type-1] += s->invariant;
1004    
1005                    if (s->length < rc->min_length[s->type-1]) {
1006                            rc->min_length[s->type-1] = s->length;
1007                    }
1008    
1009                    if (s->length > rc->max_length) {
1010                            rc->max_length = s->length;
1011                    }
1012    
1013                    if (s->type == XVID_TYPE_IVOP) {
1014                            rc->keyframe_locations[j] = i;
1015                            j++;
1016                    }
1017            }
1018    
1019            /* NB:
1020             * The "per sequence" overflow system considers a natural sequence to be
1021             * formed by all frames between two iframes, so if we want to make sure
1022             * the system does not go nuts during last sequence, we force the last
1023             * frame to appear in the keyframe locations array. */
1024            rc->keyframe_locations[j] = i;
1025    
1026            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass IFrame length: %d\n", rc->min_length[0]);
1027            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass PFrame length: %d\n", rc->min_length[1]);
1028            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Min 1st pass BFrame length: %d\n", rc->min_length[2]);
1029    }
1030    
1031    /* calculate zone weight "center" */
1032    static void
1033    zone_process(rc_2pass2_t *rc, const xvid_plg_create_t * create)
1034    {
1035            int i,j;
1036            int n = 0;
1037    
1038            rc->avg_weight = 0.0;
1039            rc->tot_quant = 0;
1040            rc->tot_quant_invariant = 0;
1041    
1042            if (create->num_zones == 0) {
1043                    for (j = 0; j < rc->num_frames; j++) {
1044                            rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1045                            rc->stats[j].weight = 1.0;
1046                    }
1047                    rc->avg_weight += rc->num_frames * 1.0;
1048                    n += rc->num_frames;
1049            }
1050    
1051    
1052            for(i=0; i < create->num_zones; i++) {
1053    
1054                    int next = (i+1<create->num_zones) ? create->zones[i+1].frame : rc->num_frames;
1055    
1056                    if (i==0 && create->zones[i].frame > 0) {
1057                            for (j = 0; j < create->zones[i].frame && j < rc->num_frames; j++) {
1058                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1059                                    rc->stats[j].weight = 1.0;
1060                            }
1061                            rc->avg_weight += create->zones[i].frame * 1.0;
1062                            n += create->zones[i].frame;
1063                    }
1064    
1065                    if (create->zones[i].mode == XVID_ZONE_WEIGHT) {
1066                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1067                                    rc->stats[j].zone_mode = XVID_ZONE_WEIGHT;
1068                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1069                            }
1070                            next -= create->zones[i].frame;
1071                            rc->avg_weight += (double)(next * create->zones[i].increment) / (double)create->zones[i].base;
1072                            n += next;
1073                    } else{  /* XVID_ZONE_QUANT */
1074                            for (j = create->zones[i].frame; j < next && j < rc->num_frames; j++ ) {
1075                                    rc->stats[j].zone_mode = XVID_ZONE_QUANT;
1076                                    rc->stats[j].weight = (double)create->zones[i].increment / (double)create->zones[i].base;
1077                                    rc->tot_quant += rc->stats[j].length;
1078                                    rc->tot_quant_invariant += rc->stats[j].invariant;
1079                            }
1080                    }
1081            }
1082            rc->avg_weight = n>0 ? rc->avg_weight/n : 1.0;
1083    
1084            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- center_weight:%f (for %d frames)  fixed_bytes:%d\n", rc->avg_weight, n, rc->tot_quant);
1085    }
1086    
1087    
1088    /* scale the curve */
1089    static void
1090    first_pass_scale_curve_internal(rc_2pass2_t *rc)
1091    {
1092            int64_t target;
1093            int64_t pass1_length;
1094            int64_t total_invariant;
1095            double scaler;
1096            int i, num_MBs;
1097    
1098            /* We only scale texture data ! */
1099            total_invariant  = rc->tot_invariant[XVID_TYPE_IVOP-1];
1100            total_invariant += rc->tot_invariant[XVID_TYPE_PVOP-1];
1101            total_invariant += rc->tot_invariant[XVID_TYPE_BVOP-1];
1102            /* don't forget to substract header bytes used in quant zones, otherwise we
1103             * counting them twice */
1104            total_invariant -= rc->tot_quant_invariant;
1105    
1106            /* We remove the bytes used by the fixed quantizer zones during first pass
1107             * with the same quants, so we know very precisely how much that
1108             * represents */
1109            target  = rc->target;
1110            target -= rc->tot_quant;
1111    
1112            /* Do the same for the first pass data */
1113            pass1_length  = rc->tot_length[XVID_TYPE_IVOP-1];
1114            pass1_length += rc->tot_length[XVID_TYPE_PVOP-1];
1115            pass1_length += rc->tot_length[XVID_TYPE_BVOP-1];
1116            pass1_length -= rc->tot_quant;
1117    
1118            /* Let's compute a linear scaler in order to perform curve scaling */
1119            scaler = (double)(target - total_invariant) / (double)(pass1_length - total_invariant);
1120    
1121    #ifdef PASS_SMALLER
1122            if ((target - total_invariant) <= 0 ||
1123                    (pass1_length - total_invariant) <= 0 ||
1124                    target >= pass1_length) {
1125                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected before correction\n");
1126                    scaler = 1.0;
1127            }
1128    #endif
1129            /* Compute min frame lengths (for each frame type) according to the number
1130             * of MBs. We sum all block type counters of frame 0, this gives us the
1131             * number of MBs.
1132             *
1133             * We compare these hardcoded values with observed values in first pass
1134             * (determined in pre_process0).Then we keep the real minimum. */
1135    
1136            /* Number of MBs */
1137            num_MBs  = rc->stats[0].blks[0];
1138            num_MBs += rc->stats[0].blks[1];
1139            num_MBs += rc->stats[0].blks[2];
1140    
1141            /* Minimum for I frames */
1142            if(rc->min_length[XVID_TYPE_IVOP-1] > ((num_MBs*22) + 240) / 8)
1143                    rc->min_length[XVID_TYPE_IVOP-1] = ((num_MBs*22) + 240) / 8;
1144    
1145            /* Minimum for P/S frames */
1146            if(rc->min_length[XVID_TYPE_PVOP-1] > ((num_MBs) + 88)  / 8)
1147                    rc->min_length[XVID_TYPE_PVOP-1] = ((num_MBs) + 88)  / 8;
1148    
1149            /* Minimum for B frames */
1150            if(rc->min_length[XVID_TYPE_BVOP-1] > 8)
1151                    rc->min_length[XVID_TYPE_BVOP-1] = 8;
1152    
1153            /* Perform an initial scale pass.
1154             *
1155             * If a frame size is scaled underneath our hardcoded minimums, then we
1156             * force the frame size to the minimum, and deduct the original & scaled
1157             * frame length from the original and target total lengths */
1158            for (i=0; i<rc->num_frames; i++) {
1159                    twopass_stat_t * s = &rc->stats[i];
1160                    int len;
1161    
1162                    /* No need to scale frame length for which a specific quantizer is
1163                     * specified thanks to zones */
1164                    if (s->zone_mode == XVID_ZONE_QUANT) {
1165                            s->scaled_length = s->length;
1166                            continue;
1167                    }
1168    
1169                    /* Compute the scaled length -- only non invariant data length is scaled */
1170                    len = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight / rc->avg_weight);
1171    
1172                    /* Compare with the computed minimum */
1173                    if (len < rc->min_length[s->type-1]) {
1174                            /* This is a 'forced size' frame, set its frame size to the
1175                             * computed minimum */
1176                            s->scaled_length = rc->min_length[s->type-1];
1177    
1178                            /* Remove both scaled and original size from their respective
1179                             * total counters, as we prepare a second pass for 'regular'
1180                             * frames */
1181                            target -= s->scaled_length;
1182                            pass1_length -= s->length;
1183                    } else {
1184                            /* Do nothing for now, we'll scale this later */
1185                            s->scaled_length = 0;
1186                    }
1187            }
1188    
1189            /* The first pass on data substracted all 'forced size' frames from the
1190             * total counters. Now, it's possible to scale the 'regular' frames. */
1191    
1192            /* Scaling factor for 'regular' frames */
1193            scaler = (double)(target - total_invariant) / (double)(pass1_length - total_invariant);
1194    
1195    #ifdef PASS_SMALLER
1196            /* Detect undersizing */
1197            if (target <= 0 || pass1_length <= 0 || target >= pass1_length) {
1198                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- WARNING: Undersize detected after correction\n");
1199                    scaler = 1.0;
1200            }
1201    #endif
1202    
1203            /* Do another pass with the new scaler */
1204            for (i=0; i<rc->num_frames; i++) {
1205                    twopass_stat_t * s = &rc->stats[i];
1206    
1207                    /* Ignore frame with forced frame sizes */
1208                    if (s->scaled_length == 0)
1209                            s->scaled_length = s->invariant + (int)((double)(s->length-s->invariant) * scaler * s->weight / rc->avg_weight);
1210            }
1211    
1212            /* Job done */
1213            return;
1214    }
1215    
1216    /* Apply all user settings to the scaled curve
1217     * This implies:
1218     *   keyframe boosting
1219     *   high/low compression */
1220    static void
1221    scaled_curve_apply_advanced_parameters(rc_2pass2_t * rc)
1222    {
1223            int i;
1224            int64_t ivop_boost_total;
1225    
1226            /* Reset the rate controller (per frame type) total byte counters */
1227            for (i=0; i<3; i++) rc->tot_scaled_length[i] = 0;
1228    
1229            /* Compute total bytes for each frame type */
1230            for (i=0; i<rc->num_frames;i++) {
1231                    twopass_stat_t *s = &rc->stats[i];
1232                    rc->tot_scaled_length[s->type-1] += s->scaled_length;
1233            }
1234    
1235            /* First we compute the total amount of bits needed, as being described by
1236             * the scaled distribution. During this pass over the complete stats data,
1237             * we see how much bits two user settings will get/give from/to p&b frames:
1238             *  - keyframe boosting
1239             *  - keyframe distance penalty */
1240            rc->KF_idx = 0;
1241            ivop_boost_total = 0;
1242            for (i=0; i<rc->num_frames; i++) {
1243                    twopass_stat_t * s = &rc->stats[i];
1244    
1245                    /* Some more work is needed for I frames */
1246                    if (s->type == XVID_TYPE_IVOP) {
1247                            int ivop_boost;
1248    
1249                            /* Accumulate bytes needed for keyframe boosting */
1250                            ivop_boost = s->scaled_length*rc->param.keyframe_boost/100;
1251    
1252    #if 0 /* ToDo: decide how to apply kfthresholding */
1253    #endif
1254                            /* If the frame size drops under the minimum length, then cap ivop_boost */
1255                            if (ivop_boost + s->scaled_length < rc->min_length[XVID_TYPE_IVOP-1])
1256                                    ivop_boost = rc->min_length[XVID_TYPE_IVOP-1] - s->scaled_length;
1257    
1258                            /* Accumulate the ivop boost */
1259                            ivop_boost_total += ivop_boost;
1260    
1261                            /* Don't forget to update the keyframe index */
1262                            rc->KF_idx++;
1263                    }
1264            }
1265    
1266            /* Initialize the IBoost tax ratio for P/S/B frames
1267             *
1268             * This ratio has to be applied to p/b/s frames in order to reserve
1269             * additional bits for keyframes (keyframe boosting) or if too much
1270             * keyframe distance is applied, bits retrieved from the keyframes.
1271             *
1272             * ie pb_length *= rc->pb_iboost_tax_ratio;
1273             *
1274             *    gives the ideal length of a p/b frame */
1275    
1276            /* Compute the total length of p/b/s frames (temporary storage into
1277             * movie_curve) */
1278            rc->pb_iboost_tax_ratio  = (double)rc->tot_scaled_length[XVID_TYPE_PVOP-1];
1279            rc->pb_iboost_tax_ratio += (double)rc->tot_scaled_length[XVID_TYPE_BVOP-1];
1280    
1281            /* Compute the ratio described above
1282             *     taxed_total = sum(0, n, tax*scaled_length)
1283             * <=> taxed_total = tax.sum(0, n, scaled_length)
1284             * <=> tax = taxed_total / original_total */
1285            rc->pb_iboost_tax_ratio =
1286                    (rc->pb_iboost_tax_ratio - ivop_boost_total) /
1287                    rc->pb_iboost_tax_ratio;
1288    
1289            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- IFrame boost tax ratio:%.2f\n",
1290                            rc->pb_iboost_tax_ratio);
1291    
1292            /* Compute the average size of frames per frame type */
1293            for(i=0; i<3; i++) {
1294                    /* Special case for missing type or weird case */
1295                    if (rc->count[i] == 0 || rc->pb_iboost_tax_ratio == 0) {
1296                            rc->avg_length[i] = 1;
1297                    } else {
1298                            rc->avg_length[i] = rc->tot_scaled_length[i];
1299    
1300                            if (i == (XVID_TYPE_IVOP-1)) {
1301                                    /* I Frames total has to be added the boost total */
1302                                    rc->avg_length[i] += ivop_boost_total;
1303                            } else {
1304                                    /* P/B frames has to taxed */
1305                                    rc->avg_length[i] *= rc->pb_iboost_tax_ratio;
1306                            }
1307    
1308                            /* Finally compute the average frame size */
1309                            rc->avg_length[i] /= (double)rc->count[i];
1310                    }
1311            }
1312    
1313            /* Assymetric curve compression */
1314            if (rc->param.curve_compression_high || rc->param.curve_compression_low) {
1315                    double symetric_total;
1316                    double assymetric_delta_total;
1317    
1318                    /* Like I frame boosting, assymetric curve compression modifies the total
1319                     * amount of needed bits, we must compute the ratio so we can prescale
1320                     lengths */
1321                    symetric_total = 0;
1322                    assymetric_delta_total = 0;
1323                    for (i=0; i<rc->num_frames; i++) {
1324                            double assymetric_delta;
1325                            double dbytes;
1326                            twopass_stat_t * s = &rc->stats[i];
1327    
1328                            /* I Frames are not concerned by assymetric scaling */
1329                            if (s->type == XVID_TYPE_IVOP)
1330                                    continue;
1331    
1332                            /* During the real run, we would have to apply the iboost tax */
1333                            dbytes = s->scaled_length * rc->pb_iboost_tax_ratio;
1334    
1335                            /* Update the symmetric curve compression total */
1336                            symetric_total += dbytes;
1337    
1338                            /* Apply assymetric curve compression */
1339                            if (dbytes > rc->avg_length[s->type-1])
1340                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_high / 100.0f;
1341                            else
1342                                    assymetric_delta = (rc->avg_length[s->type-1] - dbytes) * (double)rc->param.curve_compression_low  / 100.0f;
1343    
1344                            /* Cap to the minimum frame size if needed */
1345                            if (dbytes + assymetric_delta < rc->min_length[s->type-1])
1346                                    assymetric_delta = rc->min_length[s->type-1] - dbytes;
1347    
1348                            /* Accumulate after assymetric curve compression */
1349                            assymetric_delta_total += assymetric_delta;
1350                    }
1351    
1352                    /* Compute the tax that all p/b frames have to pay in order to respect the
1353                     * bit distribution changes that the assymetric compression curve imposes
1354                     * We want assymetric_total = sum(0, n-1, tax.scaled_length)
1355                     *      ie assymetric_total = ratio.sum(0, n-1, scaled_length)
1356                     *         ratio = assymetric_total / symmetric_total */
1357                    rc->assymetric_tax_ratio = ((double)symetric_total - (double)assymetric_delta_total) / (double)symetric_total;
1358            } else {
1359                    rc->assymetric_tax_ratio = 1.0f;
1360            }
1361    
1362            DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- Assymetric tax ratio:%.2f\n", rc->assymetric_tax_ratio);
1363    
1364            /* Last bits that need to be reset */
1365            rc->overflow = 0;
1366            rc->KFoverflow = 0;
1367            rc->KFoverflow_partial = 0;
1368            rc->KF_idx = 0;
1369            rc->desired_total = 0;
1370            rc->real_total = 0;
1371    
1372            /* Job done */
1373            return;
1374    }
1375    
1376    /*****************************************************************************
1377     * Still more low level stuff (nothing to do with stats treatment)
1378     ****************************************************************************/
1379    
1380    /* This function returns an allocated string containing a complete line read
1381     * from the file starting at the current position */
1382    static char *
1383    readline(FILE *f)
1384    {
1385            char *buffer = NULL;
1386            int buffer_size = 0;
1387            int pos = 0;
1388    
1389            do {
1390                    int c;
1391    
1392                    /* Read a character from the stream */
1393                    c = fgetc(f);
1394    
1395                    /* Is that EOF or new line ? */
1396                    if(c == EOF || c == '\n')
1397                            break;
1398    
1399                    /* Do we have to update buffer ? */
1400                    if(pos >= buffer_size - 1) {
1401                            buffer_size += BUF_SZ;
1402                            buffer = (char*)realloc(buffer, buffer_size);
1403                            if (buffer == NULL)
1404                                    return(NULL);
1405                    }
1406    
1407                    buffer[pos] = c;
1408                    pos++;
1409            } while(1);
1410    
1411            /* Read \n or EOF */
1412            if (buffer == NULL) {
1413                    /* EOF, so we reached the end of the file, return NULL */
1414                    if(feof(f))
1415                            return(NULL);
1416    
1417                    /* Just an empty line with just a newline, allocate a 1 byte buffer to
1418                     * store a zero length string */
1419                    buffer = (char*)malloc(1);
1420                    if(buffer == NULL)
1421                            return(NULL);
1422            }
1423    
1424            /* Zero terminated string */
1425            buffer[pos] = '\0';
1426    
1427            return(buffer);
1428    }
1429    
1430    /* This function returns a pointer to the first non space char in the given
1431     * string */
1432    static char *
1433    skipspaces(char *string)
1434    {
1435            const char spaces[] =
1436                    {
1437                            ' ','\t','\0'
1438                    };
1439            const char *spacechar = spaces;
1440    
1441            if (string == NULL) return(NULL);
1442    
1443            while (*string != '\0') {
1444                    /* Test against space chars */
1445                    while (*spacechar != '\0') {
1446                            if (*string == *spacechar) {
1447                                    string++;
1448                                    spacechar = spaces;
1449                                    break;
1450                            }
1451                            spacechar++;
1452                    }
1453    
1454                    /* No space char */
1455                    if (*spacechar == '\0') return(string);
1456            }
1457    
1458            return(string);
1459    }
1460    
1461    /* This function returns a boolean that tells if the string is only a
1462     * comment */
1463    static int
1464    iscomment(char *string)
1465    {
1466            const char comments[] =
1467                    {
1468                            '#',';', '%', '\0'
1469                    };
1470            const char *cmtchar = comments;
1471            int iscomment = 0;
1472    
1473            if (string == NULL) return(1);
1474    
1475            string = skipspaces(string);
1476    
1477            while(*cmtchar != '\0') {
1478                    if(*string == *cmtchar) {
1479                            iscomment = 1;
1480                            break;
1481                    }
1482                    cmtchar++;
1483            }
1484    
1485            return(iscomment);
1486    }
1487    
1488    #if 0
1489    static void
1490    stats_print(rc_2pass2_t * rc)
1491    {
1492            int i;
1493            const char frame_type[4] = { 'i', 'p', 'b', 's'};
1494    
1495            for (i=0; i<rc->num_frames; i++) {
1496                    twopass_stat_t *s = &rc->stats[i];
1497                    DPRINTF(XVID_DEBUG_RC, "[xvid rc] -- frame:%d type:%c quant:%d stats:%d scaled:%d desired:%d actual:%d overflow(%c):%.2f\n",
1498                                    i, frame_type[s->type-1], -1, s->length, s->scaled_length,
1499                                    s->desired_length, -1, frame_type[s->type-1], -1.0f);
1500            }
1501    }
1502    #endif
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