1/*
2 * H.26L/H.264/AVC/JVT/14496-10/... reference picture handling
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * H.264 / AVC / MPEG4 part10  reference picture handling.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28#include "internal.h"
29#include "dsputil.h"
30#include "avcodec.h"
31#include "h264.h"
32#include "golomb.h"
33
34//#undef NDEBUG
35#include <assert.h>
36
37
38static void pic_as_field(Picture *pic, const int parity){
39    int i;
40    for (i = 0; i < 4; ++i) {
41        if (parity == PICT_BOTTOM_FIELD)
42            pic->data[i] += pic->linesize[i];
43        pic->reference = parity;
44        pic->linesize[i] *= 2;
45    }
46    pic->poc= pic->field_poc[parity == PICT_BOTTOM_FIELD];
47}
48
49static int split_field_copy(Picture *dest, Picture *src,
50                            int parity, int id_add){
51    int match = !!(src->reference & parity);
52
53    if (match) {
54        *dest = *src;
55        if(parity != PICT_FRAME){
56            pic_as_field(dest, parity);
57            dest->pic_id *= 2;
58            dest->pic_id += id_add;
59        }
60    }
61
62    return match;
63}
64
65static int build_def_list(Picture *def, Picture **in, int len, int is_long, int sel){
66    int i[2]={0};
67    int index=0;
68
69    while(i[0]<len || i[1]<len){
70        while(i[0]<len && !(in[ i[0] ] && (in[ i[0] ]->reference & sel)))
71            i[0]++;
72        while(i[1]<len && !(in[ i[1] ] && (in[ i[1] ]->reference & (sel^3))))
73            i[1]++;
74        if(i[0] < len){
75            in[ i[0] ]->pic_id= is_long ? i[0] : in[ i[0] ]->frame_num;
76            split_field_copy(&def[index++], in[ i[0]++ ], sel  , 1);
77        }
78        if(i[1] < len){
79            in[ i[1] ]->pic_id= is_long ? i[1] : in[ i[1] ]->frame_num;
80            split_field_copy(&def[index++], in[ i[1]++ ], sel^3, 0);
81        }
82    }
83
84    return index;
85}
86
87static int add_sorted(Picture **sorted, Picture **src, int len, int limit, int dir){
88    int i, best_poc;
89    int out_i= 0;
90
91    for(;;){
92        best_poc= dir ? INT_MIN : INT_MAX;
93
94        for(i=0; i<len; i++){
95            const int poc= src[i]->poc;
96            if(((poc > limit) ^ dir) && ((poc < best_poc) ^ dir)){
97                best_poc= poc;
98                sorted[out_i]= src[i];
99            }
100        }
101        if(best_poc == (dir ? INT_MIN : INT_MAX))
102            break;
103        limit= sorted[out_i++]->poc - dir;
104    }
105    return out_i;
106}
107
108int ff_h264_fill_default_ref_list(H264Context *h){
109    MpegEncContext * const s = &h->s;
110    int i, len;
111
112    if(h->slice_type_nos==FF_B_TYPE){
113        Picture *sorted[32];
114        int cur_poc, list;
115        int lens[2];
116
117        if(FIELD_PICTURE)
118            cur_poc= s->current_picture_ptr->field_poc[ s->picture_structure == PICT_BOTTOM_FIELD ];
119        else
120            cur_poc= s->current_picture_ptr->poc;
121
122        for(list= 0; list<2; list++){
123            len= add_sorted(sorted    , h->short_ref, h->short_ref_count, cur_poc, 1^list);
124            len+=add_sorted(sorted+len, h->short_ref, h->short_ref_count, cur_poc, 0^list);
125            assert(len<=32);
126            len= build_def_list(h->default_ref_list[list]    , sorted     , len, 0, s->picture_structure);
127            len+=build_def_list(h->default_ref_list[list]+len, h->long_ref, 16 , 1, s->picture_structure);
128            assert(len<=32);
129
130            if(len < h->ref_count[list])
131                memset(&h->default_ref_list[list][len], 0, sizeof(Picture)*(h->ref_count[list] - len));
132            lens[list]= len;
133        }
134
135        if(lens[0] == lens[1] && lens[1] > 1){
136            for(i=0; h->default_ref_list[0][i].data[0] == h->default_ref_list[1][i].data[0] && i<lens[0]; i++);
137            if(i == lens[0])
138                FFSWAP(Picture, h->default_ref_list[1][0], h->default_ref_list[1][1]);
139        }
140    }else{
141        len = build_def_list(h->default_ref_list[0]    , h->short_ref, h->short_ref_count, 0, s->picture_structure);
142        len+= build_def_list(h->default_ref_list[0]+len, h-> long_ref, 16                , 1, s->picture_structure);
143        assert(len <= 32);
144        if(len < h->ref_count[0])
145            memset(&h->default_ref_list[0][len], 0, sizeof(Picture)*(h->ref_count[0] - len));
146    }
147#ifdef TRACE
148    for (i=0; i<h->ref_count[0]; i++) {
149        tprintf(h->s.avctx, "List0: %s fn:%d 0x%p\n", (h->default_ref_list[0][i].long_ref ? "LT" : "ST"), h->default_ref_list[0][i].pic_id, h->default_ref_list[0][i].data[0]);
150    }
151    if(h->slice_type_nos==FF_B_TYPE){
152        for (i=0; i<h->ref_count[1]; i++) {
153            tprintf(h->s.avctx, "List1: %s fn:%d 0x%p\n", (h->default_ref_list[1][i].long_ref ? "LT" : "ST"), h->default_ref_list[1][i].pic_id, h->default_ref_list[1][i].data[0]);
154        }
155    }
156#endif
157    return 0;
158}
159
160static void print_short_term(H264Context *h);
161static void print_long_term(H264Context *h);
162
163/**
164 * Extract structure information about the picture described by pic_num in
165 * the current decoding context (frame or field). Note that pic_num is
166 * picture number without wrapping (so, 0<=pic_num<max_pic_num).
167 * @param pic_num picture number for which to extract structure information
168 * @param structure one of PICT_XXX describing structure of picture
169 *                      with pic_num
170 * @return frame number (short term) or long term index of picture
171 *         described by pic_num
172 */
173static int pic_num_extract(H264Context *h, int pic_num, int *structure){
174    MpegEncContext * const s = &h->s;
175
176    *structure = s->picture_structure;
177    if(FIELD_PICTURE){
178        if (!(pic_num & 1))
179            /* opposite field */
180            *structure ^= PICT_FRAME;
181        pic_num >>= 1;
182    }
183
184    return pic_num;
185}
186
187int ff_h264_decode_ref_pic_list_reordering(H264Context *h){
188    MpegEncContext * const s = &h->s;
189    int list, index, pic_structure;
190
191    print_short_term(h);
192    print_long_term(h);
193
194    for(list=0; list<h->list_count; list++){
195        memcpy(h->ref_list[list], h->default_ref_list[list], sizeof(Picture)*h->ref_count[list]);
196
197        if(get_bits1(&s->gb)){
198            int pred= h->curr_pic_num;
199
200            for(index=0; ; index++){
201                unsigned int reordering_of_pic_nums_idc= get_ue_golomb_31(&s->gb);
202                unsigned int pic_id;
203                int i;
204                Picture *ref = NULL;
205
206                if(reordering_of_pic_nums_idc==3)
207                    break;
208
209                if(index >= h->ref_count[list]){
210                    av_log(h->s.avctx, AV_LOG_ERROR, "reference count overflow\n");
211                    return -1;
212                }
213
214                if(reordering_of_pic_nums_idc<3){
215                    if(reordering_of_pic_nums_idc<2){
216                        const unsigned int abs_diff_pic_num= get_ue_golomb(&s->gb) + 1;
217                        int frame_num;
218
219                        if(abs_diff_pic_num > h->max_pic_num){
220                            av_log(h->s.avctx, AV_LOG_ERROR, "abs_diff_pic_num overflow\n");
221                            return -1;
222                        }
223
224                        if(reordering_of_pic_nums_idc == 0) pred-= abs_diff_pic_num;
225                        else                                pred+= abs_diff_pic_num;
226                        pred &= h->max_pic_num - 1;
227
228                        frame_num = pic_num_extract(h, pred, &pic_structure);
229
230                        for(i= h->short_ref_count-1; i>=0; i--){
231                            ref = h->short_ref[i];
232                            assert(ref->reference);
233                            assert(!ref->long_ref);
234                            if(
235                                   ref->frame_num == frame_num &&
236                                   (ref->reference & pic_structure)
237                              )
238                                break;
239                        }
240                        if(i>=0)
241                            ref->pic_id= pred;
242                    }else{
243                        int long_idx;
244                        pic_id= get_ue_golomb(&s->gb); //long_term_pic_idx
245
246                        long_idx= pic_num_extract(h, pic_id, &pic_structure);
247
248                        if(long_idx>31){
249                            av_log(h->s.avctx, AV_LOG_ERROR, "long_term_pic_idx overflow\n");
250                            return -1;
251                        }
252                        ref = h->long_ref[long_idx];
253                        assert(!(ref && !ref->reference));
254                        if(ref && (ref->reference & pic_structure)){
255                            ref->pic_id= pic_id;
256                            assert(ref->long_ref);
257                            i=0;
258                        }else{
259                            i=-1;
260                        }
261                    }
262
263                    if (i < 0) {
264                        av_log(h->s.avctx, AV_LOG_ERROR, "reference picture missing during reorder\n");
265                        memset(&h->ref_list[list][index], 0, sizeof(Picture)); //FIXME
266                    } else {
267                        for(i=index; i+1<h->ref_count[list]; i++){
268                            if(ref->long_ref == h->ref_list[list][i].long_ref && ref->pic_id == h->ref_list[list][i].pic_id)
269                                break;
270                        }
271                        for(; i > index; i--){
272                            h->ref_list[list][i]= h->ref_list[list][i-1];
273                        }
274                        h->ref_list[list][index]= *ref;
275                        if (FIELD_PICTURE){
276                            pic_as_field(&h->ref_list[list][index], pic_structure);
277                        }
278                    }
279                }else{
280                    av_log(h->s.avctx, AV_LOG_ERROR, "illegal reordering_of_pic_nums_idc\n");
281                    return -1;
282                }
283            }
284        }
285    }
286    for(list=0; list<h->list_count; list++){
287        for(index= 0; index < h->ref_count[list]; index++){
288            if(!h->ref_list[list][index].data[0]){
289                av_log(h->s.avctx, AV_LOG_ERROR, "Missing reference picture\n");
290                if(h->default_ref_list[list][0].data[0])
291                    h->ref_list[list][index]= h->default_ref_list[list][0];
292                else
293                    return -1;
294            }
295        }
296    }
297
298    return 0;
299}
300
301void ff_h264_fill_mbaff_ref_list(H264Context *h){
302    int list, i, j;
303    for(list=0; list<2; list++){ //FIXME try list_count
304        for(i=0; i<h->ref_count[list]; i++){
305            Picture *frame = &h->ref_list[list][i];
306            Picture *field = &h->ref_list[list][16+2*i];
307            field[0] = *frame;
308            for(j=0; j<3; j++)
309                field[0].linesize[j] <<= 1;
310            field[0].reference = PICT_TOP_FIELD;
311            field[0].poc= field[0].field_poc[0];
312            field[1] = field[0];
313            for(j=0; j<3; j++)
314                field[1].data[j] += frame->linesize[j];
315            field[1].reference = PICT_BOTTOM_FIELD;
316            field[1].poc= field[1].field_poc[1];
317
318            h->luma_weight[16+2*i][list][0] = h->luma_weight[16+2*i+1][list][0] = h->luma_weight[i][list][0];
319            h->luma_weight[16+2*i][list][1] = h->luma_weight[16+2*i+1][list][1] = h->luma_weight[i][list][1];
320            for(j=0; j<2; j++){
321                h->chroma_weight[16+2*i][list][j][0] = h->chroma_weight[16+2*i+1][list][j][0] = h->chroma_weight[i][list][j][0];
322                h->chroma_weight[16+2*i][list][j][1] = h->chroma_weight[16+2*i+1][list][j][1] = h->chroma_weight[i][list][j][1];
323            }
324        }
325    }
326}
327
328/**
329 * Mark a picture as no longer needed for reference. The refmask
330 * argument allows unreferencing of individual fields or the whole frame.
331 * If the picture becomes entirely unreferenced, but is being held for
332 * display purposes, it is marked as such.
333 * @param refmask mask of fields to unreference; the mask is bitwise
334 *                anded with the reference marking of pic
335 * @return non-zero if pic becomes entirely unreferenced (except possibly
336 *         for display purposes) zero if one of the fields remains in
337 *         reference
338 */
339static inline int unreference_pic(H264Context *h, Picture *pic, int refmask){
340    int i;
341    if (pic->reference &= refmask) {
342        return 0;
343    } else {
344        for(i = 0; h->delayed_pic[i]; i++)
345            if(pic == h->delayed_pic[i]){
346                pic->reference=DELAYED_PIC_REF;
347                break;
348            }
349        return 1;
350    }
351}
352
353/**
354 * Find a Picture in the short term reference list by frame number.
355 * @param frame_num frame number to search for
356 * @param idx the index into h->short_ref where returned picture is found
357 *            undefined if no picture found.
358 * @return pointer to the found picture, or NULL if no pic with the provided
359 *                 frame number is found
360 */
361static Picture * find_short(H264Context *h, int frame_num, int *idx){
362    MpegEncContext * const s = &h->s;
363    int i;
364
365    for(i=0; i<h->short_ref_count; i++){
366        Picture *pic= h->short_ref[i];
367        if(s->avctx->debug&FF_DEBUG_MMCO)
368            av_log(h->s.avctx, AV_LOG_DEBUG, "%d %d %p\n", i, pic->frame_num, pic);
369        if(pic->frame_num == frame_num) {
370            *idx = i;
371            return pic;
372        }
373    }
374    return NULL;
375}
376
377/**
378 * Remove a picture from the short term reference list by its index in
379 * that list.  This does no checking on the provided index; it is assumed
380 * to be valid. Other list entries are shifted down.
381 * @param i index into h->short_ref of picture to remove.
382 */
383static void remove_short_at_index(H264Context *h, int i){
384    assert(i >= 0 && i < h->short_ref_count);
385    h->short_ref[i]= NULL;
386    if (--h->short_ref_count)
387        memmove(&h->short_ref[i], &h->short_ref[i+1], (h->short_ref_count - i)*sizeof(Picture*));
388}
389
390/**
391 *
392 * @return the removed picture or NULL if an error occurs
393 */
394static Picture * remove_short(H264Context *h, int frame_num, int ref_mask){
395    MpegEncContext * const s = &h->s;
396    Picture *pic;
397    int i;
398
399    if(s->avctx->debug&FF_DEBUG_MMCO)
400        av_log(h->s.avctx, AV_LOG_DEBUG, "remove short %d count %d\n", frame_num, h->short_ref_count);
401
402    pic = find_short(h, frame_num, &i);
403    if (pic){
404        if(unreference_pic(h, pic, ref_mask))
405        remove_short_at_index(h, i);
406    }
407
408    return pic;
409}
410
411/**
412 * Remove a picture from the long term reference list by its index in
413 * that list.
414 * @return the removed picture or NULL if an error occurs
415 */
416static Picture * remove_long(H264Context *h, int i, int ref_mask){
417    Picture *pic;
418
419    pic= h->long_ref[i];
420    if (pic){
421        if(unreference_pic(h, pic, ref_mask)){
422            assert(h->long_ref[i]->long_ref == 1);
423            h->long_ref[i]->long_ref= 0;
424            h->long_ref[i]= NULL;
425            h->long_ref_count--;
426        }
427    }
428
429    return pic;
430}
431
432void ff_h264_remove_all_refs(H264Context *h){
433    int i;
434
435    for(i=0; i<16; i++){
436        remove_long(h, i, 0);
437    }
438    assert(h->long_ref_count==0);
439
440    for(i=0; i<h->short_ref_count; i++){
441        unreference_pic(h, h->short_ref[i], 0);
442        h->short_ref[i]= NULL;
443    }
444    h->short_ref_count=0;
445}
446
447/**
448 * print short term list
449 */
450static void print_short_term(H264Context *h) {
451    uint32_t i;
452    if(h->s.avctx->debug&FF_DEBUG_MMCO) {
453        av_log(h->s.avctx, AV_LOG_DEBUG, "short term list:\n");
454        for(i=0; i<h->short_ref_count; i++){
455            Picture *pic= h->short_ref[i];
456            av_log(h->s.avctx, AV_LOG_DEBUG, "%d fn:%d poc:%d %p\n", i, pic->frame_num, pic->poc, pic->data[0]);
457        }
458    }
459}
460
461/**
462 * print long term list
463 */
464static void print_long_term(H264Context *h) {
465    uint32_t i;
466    if(h->s.avctx->debug&FF_DEBUG_MMCO) {
467        av_log(h->s.avctx, AV_LOG_DEBUG, "long term list:\n");
468        for(i = 0; i < 16; i++){
469            Picture *pic= h->long_ref[i];
470            if (pic) {
471                av_log(h->s.avctx, AV_LOG_DEBUG, "%d fn:%d poc:%d %p\n", i, pic->frame_num, pic->poc, pic->data[0]);
472            }
473        }
474    }
475}
476
477int ff_h264_execute_ref_pic_marking(H264Context *h, MMCO *mmco, int mmco_count){
478    MpegEncContext * const s = &h->s;
479    int i, av_uninit(j);
480    int current_ref_assigned=0;
481    Picture *av_uninit(pic);
482
483    if((s->avctx->debug&FF_DEBUG_MMCO) && mmco_count==0)
484        av_log(h->s.avctx, AV_LOG_DEBUG, "no mmco here\n");
485
486    for(i=0; i<mmco_count; i++){
487        int av_uninit(structure), av_uninit(frame_num);
488        if(s->avctx->debug&FF_DEBUG_MMCO)
489            av_log(h->s.avctx, AV_LOG_DEBUG, "mmco:%d %d %d\n", h->mmco[i].opcode, h->mmco[i].short_pic_num, h->mmco[i].long_arg);
490
491        if(   mmco[i].opcode == MMCO_SHORT2UNUSED
492           || mmco[i].opcode == MMCO_SHORT2LONG){
493            frame_num = pic_num_extract(h, mmco[i].short_pic_num, &structure);
494            pic = find_short(h, frame_num, &j);
495            if(!pic){
496                if(mmco[i].opcode != MMCO_SHORT2LONG || !h->long_ref[mmco[i].long_arg]
497                   || h->long_ref[mmco[i].long_arg]->frame_num != frame_num)
498                av_log(h->s.avctx, AV_LOG_ERROR, "mmco: unref short failure\n");
499                continue;
500            }
501        }
502
503        switch(mmco[i].opcode){
504        case MMCO_SHORT2UNUSED:
505            if(s->avctx->debug&FF_DEBUG_MMCO)
506                av_log(h->s.avctx, AV_LOG_DEBUG, "mmco: unref short %d count %d\n", h->mmco[i].short_pic_num, h->short_ref_count);
507            remove_short(h, frame_num, structure ^ PICT_FRAME);
508            break;
509        case MMCO_SHORT2LONG:
510                if (h->long_ref[mmco[i].long_arg] != pic)
511                    remove_long(h, mmco[i].long_arg, 0);
512
513                remove_short_at_index(h, j);
514                h->long_ref[ mmco[i].long_arg ]= pic;
515                if (h->long_ref[ mmco[i].long_arg ]){
516                    h->long_ref[ mmco[i].long_arg ]->long_ref=1;
517                    h->long_ref_count++;
518                }
519            break;
520        case MMCO_LONG2UNUSED:
521            j = pic_num_extract(h, mmco[i].long_arg, &structure);
522            pic = h->long_ref[j];
523            if (pic) {
524                remove_long(h, j, structure ^ PICT_FRAME);
525            } else if(s->avctx->debug&FF_DEBUG_MMCO)
526                av_log(h->s.avctx, AV_LOG_DEBUG, "mmco: unref long failure\n");
527            break;
528        case MMCO_LONG:
529                    // Comment below left from previous code as it is an interresting note.
530                    /* First field in pair is in short term list or
531                     * at a different long term index.
532                     * This is not allowed; see 7.4.3.3, notes 2 and 3.
533                     * Report the problem and keep the pair where it is,
534                     * and mark this field valid.
535                     */
536
537            if (h->long_ref[mmco[i].long_arg] != s->current_picture_ptr) {
538                remove_long(h, mmco[i].long_arg, 0);
539
540                h->long_ref[ mmco[i].long_arg ]= s->current_picture_ptr;
541                h->long_ref[ mmco[i].long_arg ]->long_ref=1;
542                h->long_ref_count++;
543            }
544
545            s->current_picture_ptr->reference |= s->picture_structure;
546            current_ref_assigned=1;
547            break;
548        case MMCO_SET_MAX_LONG:
549            assert(mmco[i].long_arg <= 16);
550            // just remove the long term which index is greater than new max
551            for(j = mmco[i].long_arg; j<16; j++){
552                remove_long(h, j, 0);
553            }
554            break;
555        case MMCO_RESET:
556            while(h->short_ref_count){
557                remove_short(h, h->short_ref[0]->frame_num, 0);
558            }
559            for(j = 0; j < 16; j++) {
560                remove_long(h, j, 0);
561            }
562            s->current_picture_ptr->poc=
563            s->current_picture_ptr->field_poc[0]=
564            s->current_picture_ptr->field_poc[1]=
565            h->poc_lsb=
566            h->poc_msb=
567            h->frame_num=
568            s->current_picture_ptr->frame_num= 0;
569            s->current_picture_ptr->mmco_reset=1;
570            break;
571        default: assert(0);
572        }
573    }
574
575    if (!current_ref_assigned) {
576        /* Second field of complementary field pair; the first field of
577         * which is already referenced. If short referenced, it
578         * should be first entry in short_ref. If not, it must exist
579         * in long_ref; trying to put it on the short list here is an
580         * error in the encoded bit stream (ref: 7.4.3.3, NOTE 2 and 3).
581         */
582        if (h->short_ref_count && h->short_ref[0] == s->current_picture_ptr) {
583            /* Just mark the second field valid */
584            s->current_picture_ptr->reference = PICT_FRAME;
585        } else if (s->current_picture_ptr->long_ref) {
586            av_log(h->s.avctx, AV_LOG_ERROR, "illegal short term reference "
587                                             "assignment for second field "
588                                             "in complementary field pair "
589                                             "(first field is long term)\n");
590        } else {
591            pic= remove_short(h, s->current_picture_ptr->frame_num, 0);
592            if(pic){
593                av_log(h->s.avctx, AV_LOG_ERROR, "illegal short term buffer state detected\n");
594            }
595
596            if(h->short_ref_count)
597                memmove(&h->short_ref[1], &h->short_ref[0], h->short_ref_count*sizeof(Picture*));
598
599            h->short_ref[0]= s->current_picture_ptr;
600            h->short_ref_count++;
601            s->current_picture_ptr->reference |= s->picture_structure;
602        }
603    }
604
605    if (h->long_ref_count + h->short_ref_count > h->sps.ref_frame_count){
606
607        /* We have too many reference frames, probably due to corrupted
608         * stream. Need to discard one frame. Prevents overrun of the
609         * short_ref and long_ref buffers.
610         */
611        av_log(h->s.avctx, AV_LOG_ERROR,
612               "number of reference frames exceeds max (probably "
613               "corrupt input), discarding one\n");
614
615        if (h->long_ref_count && !h->short_ref_count) {
616            for (i = 0; i < 16; ++i)
617                if (h->long_ref[i])
618                    break;
619
620            assert(i < 16);
621            remove_long(h, i, 0);
622        } else {
623            pic = h->short_ref[h->short_ref_count - 1];
624            remove_short(h, pic->frame_num, 0);
625        }
626    }
627
628    print_short_term(h);
629    print_long_term(h);
630    return 0;
631}
632
633int ff_h264_decode_ref_pic_marking(H264Context *h, GetBitContext *gb){
634    MpegEncContext * const s = &h->s;
635    int i;
636
637    h->mmco_index= 0;
638    if(h->nal_unit_type == NAL_IDR_SLICE){ //FIXME fields
639        s->broken_link= get_bits1(gb) -1;
640        if(get_bits1(gb)){
641            h->mmco[0].opcode= MMCO_LONG;
642            h->mmco[0].long_arg= 0;
643            h->mmco_index= 1;
644        }
645    }else{
646        if(get_bits1(gb)){ // adaptive_ref_pic_marking_mode_flag
647            for(i= 0; i<MAX_MMCO_COUNT; i++) {
648                MMCOOpcode opcode= get_ue_golomb_31(gb);
649
650                h->mmco[i].opcode= opcode;
651                if(opcode==MMCO_SHORT2UNUSED || opcode==MMCO_SHORT2LONG){
652                    h->mmco[i].short_pic_num= (h->curr_pic_num - get_ue_golomb(gb) - 1) & (h->max_pic_num - 1);
653/*                    if(h->mmco[i].short_pic_num >= h->short_ref_count || h->short_ref[ h->mmco[i].short_pic_num ] == NULL){
654                        av_log(s->avctx, AV_LOG_ERROR, "illegal short ref in memory management control operation %d\n", mmco);
655                        return -1;
656                    }*/
657                }
658                if(opcode==MMCO_SHORT2LONG || opcode==MMCO_LONG2UNUSED || opcode==MMCO_LONG || opcode==MMCO_SET_MAX_LONG){
659                    unsigned int long_arg= get_ue_golomb_31(gb);
660                    if(long_arg >= 32 || (long_arg >= 16 && !(opcode == MMCO_LONG2UNUSED && FIELD_PICTURE))){
661                        av_log(h->s.avctx, AV_LOG_ERROR, "illegal long ref in memory management control operation %d\n", opcode);
662                        return -1;
663                    }
664                    h->mmco[i].long_arg= long_arg;
665                }
666
667                if(opcode > (unsigned)MMCO_LONG){
668                    av_log(h->s.avctx, AV_LOG_ERROR, "illegal memory management control operation %d\n", opcode);
669                    return -1;
670                }
671                if(opcode == MMCO_END)
672                    break;
673            }
674            h->mmco_index= i;
675        }else{
676            assert(h->long_ref_count + h->short_ref_count <= h->sps.ref_frame_count);
677
678            if(h->short_ref_count && h->long_ref_count + h->short_ref_count == h->sps.ref_frame_count &&
679                    !(FIELD_PICTURE && !s->first_field && s->current_picture_ptr->reference)) {
680                h->mmco[0].opcode= MMCO_SHORT2UNUSED;
681                h->mmco[0].short_pic_num= h->short_ref[ h->short_ref_count - 1 ]->frame_num;
682                h->mmco_index= 1;
683                if (FIELD_PICTURE) {
684                    h->mmco[0].short_pic_num *= 2;
685                    h->mmco[1].opcode= MMCO_SHORT2UNUSED;
686                    h->mmco[1].short_pic_num= h->mmco[0].short_pic_num + 1;
687                    h->mmco_index= 2;
688                }
689            }
690        }
691    }
692
693    return 0;
694}
695