xref: /third_party/ffmpeg/libavcodec/h264_refs.c (revision cabdff1a)
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 / MPEG-4 part10  reference picture handling.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28#include <inttypes.h>
29
30#include "libavutil/avassert.h"
31#include "avcodec.h"
32#include "h264.h"
33#include "h264dec.h"
34#include "golomb.h"
35#include "mpegutils.h"
36
37#include <assert.h>
38
39static void pic_as_field(H264Ref *pic, const int parity)
40{
41    int i;
42    for (i = 0; i < FF_ARRAY_ELEMS(pic->data); ++i) {
43        if (parity == PICT_BOTTOM_FIELD)
44            pic->data[i]   += pic->linesize[i];
45        pic->reference      = parity;
46        pic->linesize[i] *= 2;
47    }
48    pic->poc = pic->parent->field_poc[parity == PICT_BOTTOM_FIELD];
49}
50
51static void ref_from_h264pic(H264Ref *dst, H264Picture *src)
52{
53    memcpy(dst->data,     src->f->data,     sizeof(dst->data));
54    memcpy(dst->linesize, src->f->linesize, sizeof(dst->linesize));
55    dst->reference = src->reference;
56    dst->poc       = src->poc;
57    dst->pic_id    = src->pic_id;
58    dst->parent = src;
59}
60
61static int split_field_copy(H264Ref *dest, H264Picture *src, int parity, int id_add)
62{
63    int match = !!(src->reference & parity);
64
65    if (match) {
66        ref_from_h264pic(dest, src);
67        if (parity != PICT_FRAME) {
68            pic_as_field(dest, parity);
69            dest->pic_id *= 2;
70            dest->pic_id += id_add;
71        }
72    }
73
74    return match;
75}
76
77static int build_def_list(H264Ref *def, int def_len,
78                          H264Picture * const *in, int len, int is_long, int sel)
79{
80    int  i[2] = { 0 };
81    int index = 0;
82
83    while (i[0] < len || i[1] < len) {
84        while (i[0] < len && !(in[i[0]] && (in[i[0]]->reference & sel)))
85            i[0]++;
86        while (i[1] < len && !(in[i[1]] && (in[i[1]]->reference & (sel ^ 3))))
87            i[1]++;
88        if (i[0] < len) {
89            av_assert0(index < def_len);
90            in[i[0]]->pic_id = is_long ? i[0] : in[i[0]]->frame_num;
91            split_field_copy(&def[index++], in[i[0]++], sel, 1);
92        }
93        if (i[1] < len) {
94            av_assert0(index < def_len);
95            in[i[1]]->pic_id = is_long ? i[1] : in[i[1]]->frame_num;
96            split_field_copy(&def[index++], in[i[1]++], sel ^ 3, 0);
97        }
98    }
99
100    return index;
101}
102
103static int add_sorted(H264Picture **sorted, H264Picture * const *src,
104                      int len, int limit, int dir)
105{
106    int i, best_poc;
107    int out_i = 0;
108
109    for (;;) {
110        best_poc = dir ? INT_MIN : INT_MAX;
111
112        for (i = 0; i < len; i++) {
113            const int poc = src[i]->poc;
114            if (((poc > limit) ^ dir) && ((poc < best_poc) ^ dir)) {
115                best_poc      = poc;
116                sorted[out_i] = src[i];
117            }
118        }
119        if (best_poc == (dir ? INT_MIN : INT_MAX))
120            break;
121        limit = sorted[out_i++]->poc - dir;
122    }
123    return out_i;
124}
125
126static int mismatches_ref(const H264Context *h, const H264Picture *pic)
127{
128    const AVFrame *f = pic->f;
129    return (h->cur_pic_ptr->f->width  != f->width ||
130            h->cur_pic_ptr->f->height != f->height ||
131            h->cur_pic_ptr->f->format != f->format);
132}
133
134static void h264_initialise_ref_list(H264Context *h, H264SliceContext *sl)
135{
136    int i, len;
137    int j;
138
139    if (sl->slice_type_nos == AV_PICTURE_TYPE_B) {
140        H264Picture *sorted[32];
141        int cur_poc, list;
142        int lens[2];
143
144        if (FIELD_PICTURE(h))
145            cur_poc = h->cur_pic_ptr->field_poc[h->picture_structure == PICT_BOTTOM_FIELD];
146        else
147            cur_poc = h->cur_pic_ptr->poc;
148
149        for (list = 0; list < 2; list++) {
150            len  = add_sorted(sorted,       h->short_ref, h->short_ref_count, cur_poc, 1 ^ list);
151            len += add_sorted(sorted + len, h->short_ref, h->short_ref_count, cur_poc, 0 ^ list);
152            av_assert0(len <= 32);
153
154            len  = build_def_list(sl->ref_list[list], FF_ARRAY_ELEMS(sl->ref_list[0]),
155                                  sorted, len, 0, h->picture_structure);
156            len += build_def_list(sl->ref_list[list] + len,
157                                  FF_ARRAY_ELEMS(sl->ref_list[0]) - len,
158                                  h->long_ref, 16, 1, h->picture_structure);
159            av_assert0(len <= 32);
160
161            if (len < sl->ref_count[list])
162                memset(&sl->ref_list[list][len], 0, sizeof(H264Ref) * (sl->ref_count[list] - len));
163            lens[list] = len;
164        }
165
166        if (lens[0] == lens[1] && lens[1] > 1) {
167            for (i = 0; i < lens[0] &&
168                        sl->ref_list[0][i].parent->f->buf[0]->buffer ==
169                        sl->ref_list[1][i].parent->f->buf[0]->buffer; i++);
170            if (i == lens[0]) {
171                FFSWAP(H264Ref, sl->ref_list[1][0], sl->ref_list[1][1]);
172            }
173        }
174    } else {
175        len  = build_def_list(sl->ref_list[0], FF_ARRAY_ELEMS(sl->ref_list[0]),
176                              h->short_ref, h->short_ref_count, 0, h->picture_structure);
177        len += build_def_list(sl->ref_list[0] + len,
178                              FF_ARRAY_ELEMS(sl->ref_list[0]) - len,
179                              h-> long_ref, 16, 1, h->picture_structure);
180        av_assert0(len <= 32);
181
182        if (len < sl->ref_count[0])
183            memset(&sl->ref_list[0][len], 0, sizeof(H264Ref) * (sl->ref_count[0] - len));
184    }
185#ifdef TRACE
186    for (i = 0; i < sl->ref_count[0]; i++) {
187        ff_tlog(h->avctx, "List0: %s fn:%d 0x%p\n",
188                (sl->ref_list[0][i].parent ? (sl->ref_list[0][i].parent->long_ref ? "LT" : "ST") : "??"),
189                sl->ref_list[0][i].pic_id,
190                sl->ref_list[0][i].data[0]);
191    }
192    if (sl->slice_type_nos == AV_PICTURE_TYPE_B) {
193        for (i = 0; i < sl->ref_count[1]; i++) {
194            ff_tlog(h->avctx, "List1: %s fn:%d 0x%p\n",
195                    (sl->ref_list[1][i].parent ? (sl->ref_list[1][i].parent->long_ref ? "LT" : "ST") : "??"),
196                    sl->ref_list[1][i].pic_id,
197                    sl->ref_list[1][i].data[0]);
198        }
199    }
200#endif
201
202    for (j = 0; j<1+(sl->slice_type_nos == AV_PICTURE_TYPE_B); j++) {
203        for (i = 0; i < sl->ref_count[j]; i++) {
204            if (sl->ref_list[j][i].parent) {
205                if (mismatches_ref(h, sl->ref_list[j][i].parent)) {
206                    av_log(h->avctx, AV_LOG_ERROR, "Discarding mismatching reference\n");
207                    memset(&sl->ref_list[j][i], 0, sizeof(sl->ref_list[j][i]));
208                }
209            }
210        }
211    }
212    for (i = 0; i < sl->list_count; i++)
213        h->default_ref[i] = sl->ref_list[i][0];
214}
215
216/**
217 * print short term list
218 */
219static void print_short_term(const H264Context *h)
220{
221    uint32_t i;
222    if (h->avctx->debug & FF_DEBUG_MMCO) {
223        av_log(h->avctx, AV_LOG_DEBUG, "short term list:\n");
224        for (i = 0; i < h->short_ref_count; i++) {
225            H264Picture *pic = h->short_ref[i];
226            av_log(h->avctx, AV_LOG_DEBUG, "%"PRIu32" fn:%d poc:%d %p\n",
227                   i, pic->frame_num, pic->poc, pic->f->data[0]);
228        }
229    }
230}
231
232/**
233 * print long term list
234 */
235static void print_long_term(const H264Context *h)
236{
237    uint32_t i;
238    if (h->avctx->debug & FF_DEBUG_MMCO) {
239        av_log(h->avctx, AV_LOG_DEBUG, "long term list:\n");
240        for (i = 0; i < 16; i++) {
241            H264Picture *pic = h->long_ref[i];
242            if (pic) {
243                av_log(h->avctx, AV_LOG_DEBUG, "%"PRIu32" fn:%d poc:%d %p\n",
244                       i, pic->frame_num, pic->poc, pic->f->data[0]);
245            }
246        }
247    }
248}
249
250/**
251 * Extract structure information about the picture described by pic_num in
252 * the current decoding context (frame or field). Note that pic_num is
253 * picture number without wrapping (so, 0<=pic_num<max_pic_num).
254 * @param pic_num picture number for which to extract structure information
255 * @param structure one of PICT_XXX describing structure of picture
256 *                      with pic_num
257 * @return frame number (short term) or long term index of picture
258 *         described by pic_num
259 */
260static int pic_num_extract(const H264Context *h, int pic_num, int *structure)
261{
262    *structure = h->picture_structure;
263    if (FIELD_PICTURE(h)) {
264        if (!(pic_num & 1))
265            /* opposite field */
266            *structure ^= PICT_FRAME;
267        pic_num >>= 1;
268    }
269
270    return pic_num;
271}
272
273static void h264_fill_mbaff_ref_list(H264SliceContext *sl)
274{
275    int list, i, j;
276    for (list = 0; list < sl->list_count; list++) {
277        for (i = 0; i < sl->ref_count[list]; i++) {
278            H264Ref *frame = &sl->ref_list[list][i];
279            H264Ref *field = &sl->ref_list[list][16 + 2 * i];
280
281            field[0] = *frame;
282
283            for (j = 0; j < 3; j++)
284                field[0].linesize[j] <<= 1;
285            field[0].reference = PICT_TOP_FIELD;
286            field[0].poc       = field[0].parent->field_poc[0];
287
288            field[1] = field[0];
289
290            for (j = 0; j < 3; j++)
291                field[1].data[j] += frame->parent->f->linesize[j];
292            field[1].reference = PICT_BOTTOM_FIELD;
293            field[1].poc       = field[1].parent->field_poc[1];
294        }
295    }
296}
297
298int ff_h264_build_ref_list(H264Context *h, H264SliceContext *sl)
299{
300    int list, index, pic_structure;
301
302    print_short_term(h);
303    print_long_term(h);
304
305    h264_initialise_ref_list(h, sl);
306
307    for (list = 0; list < sl->list_count; list++) {
308        int pred = sl->curr_pic_num;
309
310        for (index = 0; index < sl->nb_ref_modifications[list]; index++) {
311            unsigned int modification_of_pic_nums_idc = sl->ref_modifications[list][index].op;
312            unsigned int                          val = sl->ref_modifications[list][index].val;
313            unsigned int pic_id;
314            int i;
315            H264Picture *ref = NULL;
316
317            switch (modification_of_pic_nums_idc) {
318            case 0:
319            case 1: {
320                const unsigned int abs_diff_pic_num = val + 1;
321                int frame_num;
322
323                if (abs_diff_pic_num > sl->max_pic_num) {
324                    av_log(h->avctx, AV_LOG_ERROR,
325                           "abs_diff_pic_num overflow\n");
326                    return AVERROR_INVALIDDATA;
327                }
328
329                if (modification_of_pic_nums_idc == 0)
330                    pred -= abs_diff_pic_num;
331                else
332                    pred += abs_diff_pic_num;
333                pred &= sl->max_pic_num - 1;
334
335                frame_num = pic_num_extract(h, pred, &pic_structure);
336
337                for (i = h->short_ref_count - 1; i >= 0; i--) {
338                    ref = h->short_ref[i];
339                    assert(ref->reference);
340                    assert(!ref->long_ref);
341                    if (ref->frame_num == frame_num &&
342                        (ref->reference & pic_structure))
343                        break;
344                }
345                if (i >= 0)
346                    ref->pic_id = pred;
347                break;
348            }
349            case 2: {
350                int long_idx;
351                pic_id = val; // long_term_pic_idx
352
353                long_idx = pic_num_extract(h, pic_id, &pic_structure);
354
355                if (long_idx > 31U) {
356                    av_log(h->avctx, AV_LOG_ERROR,
357                           "long_term_pic_idx overflow\n");
358                    return AVERROR_INVALIDDATA;
359                }
360                ref = h->long_ref[long_idx];
361                assert(!(ref && !ref->reference));
362                if (ref && (ref->reference & pic_structure)) {
363                    ref->pic_id = pic_id;
364                    assert(ref->long_ref);
365                    i = 0;
366                } else {
367                    i = -1;
368                }
369                break;
370            }
371            default:
372                av_assert0(0);
373            }
374
375            if (i < 0 || mismatches_ref(h, ref)) {
376                av_log(h->avctx, AV_LOG_ERROR,
377                       i < 0 ? "reference picture missing during reorder\n" :
378                               "mismatching reference\n"
379                      );
380                memset(&sl->ref_list[list][index], 0, sizeof(sl->ref_list[0][0])); // FIXME
381            } else {
382                for (i = index; i + 1 < sl->ref_count[list]; i++) {
383                    if (sl->ref_list[list][i].parent &&
384                        ref->long_ref == sl->ref_list[list][i].parent->long_ref &&
385                        ref->pic_id   == sl->ref_list[list][i].pic_id)
386                        break;
387                }
388                for (; i > index; i--) {
389                    sl->ref_list[list][i] = sl->ref_list[list][i - 1];
390                }
391                ref_from_h264pic(&sl->ref_list[list][index], ref);
392                if (FIELD_PICTURE(h)) {
393                    pic_as_field(&sl->ref_list[list][index], pic_structure);
394                }
395            }
396        }
397    }
398    for (list = 0; list < sl->list_count; list++) {
399        for (index = 0; index < sl->ref_count[list]; index++) {
400            if (   !sl->ref_list[list][index].parent
401                || (!FIELD_PICTURE(h) && (sl->ref_list[list][index].reference&3) != 3)) {
402                int i;
403                av_log(h->avctx, AV_LOG_ERROR, "Missing reference picture, default is %d\n", h->default_ref[list].poc);
404                for (i = 0; i < FF_ARRAY_ELEMS(h->last_pocs); i++)
405                    h->last_pocs[i] = INT_MIN;
406                if (h->default_ref[list].parent
407                    && !(!FIELD_PICTURE(h) && (h->default_ref[list].reference&3) != 3))
408                    sl->ref_list[list][index] = h->default_ref[list];
409                else
410                    return -1;
411            }
412            av_assert0(av_buffer_get_ref_count(sl->ref_list[list][index].parent->f->buf[0]) > 0);
413        }
414    }
415
416    if (FRAME_MBAFF(h))
417        h264_fill_mbaff_ref_list(sl);
418
419    return 0;
420}
421
422int ff_h264_decode_ref_pic_list_reordering(H264SliceContext *sl, void *logctx)
423{
424    int list, index;
425
426    sl->nb_ref_modifications[0] = 0;
427    sl->nb_ref_modifications[1] = 0;
428
429    for (list = 0; list < sl->list_count; list++) {
430        if (!get_bits1(&sl->gb))    // ref_pic_list_modification_flag_l[01]
431            continue;
432
433        for (index = 0; ; index++) {
434            unsigned int op = get_ue_golomb_31(&sl->gb);
435
436            if (op == 3)
437                break;
438
439            if (index >= sl->ref_count[list]) {
440                av_log(logctx, AV_LOG_ERROR, "reference count overflow\n");
441                return AVERROR_INVALIDDATA;
442            } else if (op > 2) {
443                av_log(logctx, AV_LOG_ERROR,
444                       "illegal modification_of_pic_nums_idc %u\n",
445                       op);
446                return AVERROR_INVALIDDATA;
447            }
448            sl->ref_modifications[list][index].val = get_ue_golomb_long(&sl->gb);
449            sl->ref_modifications[list][index].op  = op;
450            sl->nb_ref_modifications[list]++;
451        }
452    }
453
454    return 0;
455}
456
457/**
458 * Mark a picture as no longer needed for reference. The refmask
459 * argument allows unreferencing of individual fields or the whole frame.
460 * If the picture becomes entirely unreferenced, but is being held for
461 * display purposes, it is marked as such.
462 * @param refmask mask of fields to unreference; the mask is bitwise
463 *                anded with the reference marking of pic
464 * @return non-zero if pic becomes entirely unreferenced (except possibly
465 *         for display purposes) zero if one of the fields remains in
466 *         reference
467 */
468static inline int unreference_pic(H264Context *h, H264Picture *pic, int refmask)
469{
470    int i;
471    if (pic->reference &= refmask) {
472        return 0;
473    } else {
474        for(i = 0; h->delayed_pic[i]; i++)
475            if(pic == h->delayed_pic[i]){
476                pic->reference = DELAYED_PIC_REF;
477                break;
478            }
479        return 1;
480    }
481}
482
483/**
484 * Find a H264Picture in the short term reference list by frame number.
485 * @param frame_num frame number to search for
486 * @param idx the index into h->short_ref where returned picture is found
487 *            undefined if no picture found.
488 * @return pointer to the found picture, or NULL if no pic with the provided
489 *                 frame number is found
490 */
491static H264Picture *find_short(H264Context *h, int frame_num, int *idx)
492{
493    int i;
494
495    for (i = 0; i < h->short_ref_count; i++) {
496        H264Picture *pic = h->short_ref[i];
497        if (h->avctx->debug & FF_DEBUG_MMCO)
498            av_log(h->avctx, AV_LOG_DEBUG, "%d %d %p\n", i, pic->frame_num, pic);
499        if (pic->frame_num == frame_num) {
500            *idx = i;
501            return pic;
502        }
503    }
504    return NULL;
505}
506
507/**
508 * Remove a picture from the short term reference list by its index in
509 * that list.  This does no checking on the provided index; it is assumed
510 * to be valid. Other list entries are shifted down.
511 * @param i index into h->short_ref of picture to remove.
512 */
513static void remove_short_at_index(H264Context *h, int i)
514{
515    assert(i >= 0 && i < h->short_ref_count);
516    h->short_ref[i] = NULL;
517    if (--h->short_ref_count)
518        memmove(&h->short_ref[i], &h->short_ref[i + 1],
519                (h->short_ref_count - i) * sizeof(H264Picture*));
520}
521
522/**
523 * @return the removed picture or NULL if an error occurs
524 */
525static H264Picture *remove_short(H264Context *h, int frame_num, int ref_mask)
526{
527    H264Picture *pic;
528    int i;
529
530    if (h->avctx->debug & FF_DEBUG_MMCO)
531        av_log(h->avctx, AV_LOG_DEBUG, "remove short %d count %d\n", frame_num, h->short_ref_count);
532
533    pic = find_short(h, frame_num, &i);
534    if (pic) {
535        if (unreference_pic(h, pic, ref_mask))
536            remove_short_at_index(h, i);
537    }
538
539    return pic;
540}
541
542/**
543 * Remove a picture from the long term reference list by its index in
544 * that list.
545 * @return the removed picture or NULL if an error occurs
546 */
547static H264Picture *remove_long(H264Context *h, int i, int ref_mask)
548{
549    H264Picture *pic;
550
551    pic = h->long_ref[i];
552    if (pic) {
553        if (unreference_pic(h, pic, ref_mask)) {
554            assert(h->long_ref[i]->long_ref == 1);
555            h->long_ref[i]->long_ref = 0;
556            h->long_ref[i]           = NULL;
557            h->long_ref_count--;
558        }
559    }
560
561    return pic;
562}
563
564void ff_h264_remove_all_refs(H264Context *h)
565{
566    int i;
567
568    for (i = 0; i < 16; i++) {
569        remove_long(h, i, 0);
570    }
571    assert(h->long_ref_count == 0);
572
573    if (h->short_ref_count && !h->last_pic_for_ec.f->data[0]) {
574        ff_h264_unref_picture(h, &h->last_pic_for_ec);
575        ff_h264_ref_picture(h, &h->last_pic_for_ec, h->short_ref[0]);
576    }
577
578    for (i = 0; i < h->short_ref_count; i++) {
579        unreference_pic(h, h->short_ref[i], 0);
580        h->short_ref[i] = NULL;
581    }
582    h->short_ref_count = 0;
583
584    memset(h->default_ref, 0, sizeof(h->default_ref));
585}
586
587static void generate_sliding_window_mmcos(H264Context *h)
588{
589    MMCO *mmco = h->mmco;
590    int nb_mmco = 0;
591
592    if (h->short_ref_count &&
593        h->long_ref_count + h->short_ref_count >= h->ps.sps->ref_frame_count &&
594        !(FIELD_PICTURE(h) && !h->first_field && h->cur_pic_ptr->reference)) {
595        mmco[0].opcode        = MMCO_SHORT2UNUSED;
596        mmco[0].short_pic_num = h->short_ref[h->short_ref_count - 1]->frame_num;
597        nb_mmco               = 1;
598        if (FIELD_PICTURE(h)) {
599            mmco[0].short_pic_num *= 2;
600            mmco[1].opcode         = MMCO_SHORT2UNUSED;
601            mmco[1].short_pic_num  = mmco[0].short_pic_num + 1;
602            nb_mmco                = 2;
603        }
604    }
605
606    h->nb_mmco = nb_mmco;
607}
608
609int ff_h264_execute_ref_pic_marking(H264Context *h)
610{
611    MMCO *mmco = h->mmco;
612    int mmco_count;
613    int i, av_uninit(j);
614    int pps_ref_count[2] = {0};
615    int current_ref_assigned = 0, err = 0;
616    H264Picture *av_uninit(pic);
617
618    if (!h->ps.sps) {
619        av_log(h->avctx, AV_LOG_ERROR, "SPS is unset\n");
620        err = AVERROR_INVALIDDATA;
621        goto out;
622    }
623
624    if (!h->explicit_ref_marking)
625        generate_sliding_window_mmcos(h);
626    mmco_count = h->nb_mmco;
627
628    if ((h->avctx->debug & FF_DEBUG_MMCO) && mmco_count == 0)
629        av_log(h->avctx, AV_LOG_DEBUG, "no mmco here\n");
630
631    for (i = 0; i < mmco_count; i++) {
632        int av_uninit(structure), av_uninit(frame_num);
633        if (h->avctx->debug & FF_DEBUG_MMCO)
634            av_log(h->avctx, AV_LOG_DEBUG, "mmco:%d %d %d\n", h->mmco[i].opcode,
635                   h->mmco[i].short_pic_num, h->mmco[i].long_arg);
636
637        if (mmco[i].opcode == MMCO_SHORT2UNUSED ||
638            mmco[i].opcode == MMCO_SHORT2LONG) {
639            frame_num = pic_num_extract(h, mmco[i].short_pic_num, &structure);
640            pic       = find_short(h, frame_num, &j);
641            if (!pic) {
642                if (mmco[i].opcode != MMCO_SHORT2LONG ||
643                    !h->long_ref[mmco[i].long_arg]    ||
644                    h->long_ref[mmco[i].long_arg]->frame_num != frame_num) {
645                    av_log(h->avctx, h->short_ref_count ? AV_LOG_ERROR : AV_LOG_DEBUG, "mmco: unref short failure\n");
646                    err = AVERROR_INVALIDDATA;
647                }
648                continue;
649            }
650        }
651
652        switch (mmco[i].opcode) {
653        case MMCO_SHORT2UNUSED:
654            if (h->avctx->debug & FF_DEBUG_MMCO)
655                av_log(h->avctx, AV_LOG_DEBUG, "mmco: unref short %d count %d\n",
656                       h->mmco[i].short_pic_num, h->short_ref_count);
657            remove_short(h, frame_num, structure ^ PICT_FRAME);
658            break;
659        case MMCO_SHORT2LONG:
660                if (h->long_ref[mmco[i].long_arg] != pic)
661                    remove_long(h, mmco[i].long_arg, 0);
662
663                remove_short_at_index(h, j);
664                h->long_ref[ mmco[i].long_arg ] = pic;
665                if (h->long_ref[mmco[i].long_arg]) {
666                    h->long_ref[mmco[i].long_arg]->long_ref = 1;
667                    h->long_ref_count++;
668                }
669            break;
670        case MMCO_LONG2UNUSED:
671            j   = pic_num_extract(h, mmco[i].long_arg, &structure);
672            pic = h->long_ref[j];
673            if (pic) {
674                remove_long(h, j, structure ^ PICT_FRAME);
675            } else if (h->avctx->debug & FF_DEBUG_MMCO)
676                av_log(h->avctx, AV_LOG_DEBUG, "mmco: unref long failure\n");
677            break;
678        case MMCO_LONG:
679                    // Comment below left from previous code as it is an interesting note.
680                    /* First field in pair is in short term list or
681                     * at a different long term index.
682                     * This is not allowed; see 7.4.3.3, notes 2 and 3.
683                     * Report the problem and keep the pair where it is,
684                     * and mark this field valid.
685                     */
686            if (h->short_ref[0] == h->cur_pic_ptr) {
687                av_log(h->avctx, AV_LOG_ERROR, "mmco: cannot assign current picture to short and long at the same time\n");
688                remove_short_at_index(h, 0);
689            }
690
691            /* make sure the current picture is not already assigned as a long ref */
692            if (h->cur_pic_ptr->long_ref) {
693                for (j = 0; j < FF_ARRAY_ELEMS(h->long_ref); j++) {
694                    if (h->long_ref[j] == h->cur_pic_ptr) {
695                        if (j != mmco[i].long_arg)
696                            av_log(h->avctx, AV_LOG_ERROR, "mmco: cannot assign current picture to 2 long term references\n");
697                        remove_long(h, j, 0);
698                    }
699                }
700            }
701
702            if (h->long_ref[mmco[i].long_arg] != h->cur_pic_ptr) {
703                av_assert0(!h->cur_pic_ptr->long_ref);
704                remove_long(h, mmco[i].long_arg, 0);
705
706                h->long_ref[mmco[i].long_arg]           = h->cur_pic_ptr;
707                h->long_ref[mmco[i].long_arg]->long_ref = 1;
708                h->long_ref_count++;
709            }
710
711            h->cur_pic_ptr->reference |= h->picture_structure;
712            current_ref_assigned = 1;
713            break;
714        case MMCO_SET_MAX_LONG:
715            assert(mmco[i].long_arg <= 16);
716            // just remove the long term which index is greater than new max
717            for (j = mmco[i].long_arg; j < 16; j++) {
718                remove_long(h, j, 0);
719            }
720            break;
721        case MMCO_RESET:
722            while (h->short_ref_count) {
723                remove_short(h, h->short_ref[0]->frame_num, 0);
724            }
725            for (j = 0; j < 16; j++) {
726                remove_long(h, j, 0);
727            }
728            h->poc.frame_num = h->cur_pic_ptr->frame_num = 0;
729            h->mmco_reset = 1;
730            h->cur_pic_ptr->mmco_reset = 1;
731            for (j = 0; j < FF_ARRAY_ELEMS(h->last_pocs); j++)
732                h->last_pocs[j] = INT_MIN;
733            break;
734        default: av_assert0(0);
735        }
736    }
737
738    if (!current_ref_assigned) {
739        /* Second field of complementary field pair; the first field of
740         * which is already referenced. If short referenced, it
741         * should be first entry in short_ref. If not, it must exist
742         * in long_ref; trying to put it on the short list here is an
743         * error in the encoded bit stream (ref: 7.4.3.3, NOTE 2 and 3).
744         */
745        if (h->short_ref_count && h->short_ref[0] == h->cur_pic_ptr) {
746            /* Just mark the second field valid */
747            h->cur_pic_ptr->reference |= h->picture_structure;
748        } else if (h->cur_pic_ptr->long_ref) {
749            av_log(h->avctx, AV_LOG_ERROR, "illegal short term reference "
750                                           "assignment for second field "
751                                           "in complementary field pair "
752                                           "(first field is long term)\n");
753            err = AVERROR_INVALIDDATA;
754        } else {
755            pic = remove_short(h, h->cur_pic_ptr->frame_num, 0);
756            if (pic) {
757                av_log(h->avctx, AV_LOG_ERROR, "illegal short term buffer state detected\n");
758                err = AVERROR_INVALIDDATA;
759            }
760
761            if (h->short_ref_count)
762                memmove(&h->short_ref[1], &h->short_ref[0],
763                        h->short_ref_count * sizeof(H264Picture*));
764
765            h->short_ref[0] = h->cur_pic_ptr;
766            h->short_ref_count++;
767            h->cur_pic_ptr->reference |= h->picture_structure;
768        }
769    }
770
771    if (h->long_ref_count + h->short_ref_count > FFMAX(h->ps.sps->ref_frame_count, 1)) {
772
773        /* We have too many reference frames, probably due to corrupted
774         * stream. Need to discard one frame. Prevents overrun of the
775         * short_ref and long_ref buffers.
776         */
777        av_log(h->avctx, AV_LOG_ERROR,
778               "number of reference frames (%d+%d) exceeds max (%d; probably "
779               "corrupt input), discarding one\n",
780               h->long_ref_count, h->short_ref_count, h->ps.sps->ref_frame_count);
781        err = AVERROR_INVALIDDATA;
782
783        if (h->long_ref_count && !h->short_ref_count) {
784            for (i = 0; i < 16; ++i)
785                if (h->long_ref[i])
786                    break;
787
788            assert(i < 16);
789            remove_long(h, i, 0);
790        } else {
791            pic = h->short_ref[h->short_ref_count - 1];
792            remove_short(h, pic->frame_num, 0);
793        }
794    }
795
796    for (i = 0; i<h->short_ref_count; i++) {
797        pic = h->short_ref[i];
798        if (pic->invalid_gap) {
799            int d = av_mod_uintp2(h->cur_pic_ptr->frame_num - pic->frame_num, h->ps.sps->log2_max_frame_num);
800            if (d > h->ps.sps->ref_frame_count)
801                remove_short(h, pic->frame_num, 0);
802        }
803    }
804
805    print_short_term(h);
806    print_long_term(h);
807
808    for (i = 0; i < FF_ARRAY_ELEMS(h->ps.pps_list); i++) {
809        if (h->ps.pps_list[i]) {
810            const PPS *pps = (const PPS *)h->ps.pps_list[i]->data;
811            pps_ref_count[0] = FFMAX(pps_ref_count[0], pps->ref_count[0]);
812            pps_ref_count[1] = FFMAX(pps_ref_count[1], pps->ref_count[1]);
813        }
814    }
815
816    // Detect unmarked random access points
817    if (   err >= 0
818        && h->long_ref_count==0
819        && (   h->short_ref_count<=2
820            || pps_ref_count[0] <= 2 && pps_ref_count[1] <= 1 && h->avctx->has_b_frames
821            || pps_ref_count[0] <= 1 + (h->picture_structure != PICT_FRAME) && pps_ref_count[1] <= 1)
822        && pps_ref_count[0]<=2 + (h->picture_structure != PICT_FRAME) + (2*!h->has_recovery_point)
823        && h->cur_pic_ptr->f->pict_type == AV_PICTURE_TYPE_I){
824        h->cur_pic_ptr->recovered |= 1;
825        if(!h->avctx->has_b_frames)
826            h->frame_recovered |= FRAME_RECOVERED_SEI;
827    }
828
829out:
830    return (h->avctx->err_recognition & AV_EF_EXPLODE) ? err : 0;
831}
832
833int ff_h264_decode_ref_pic_marking(H264SliceContext *sl, GetBitContext *gb,
834                                   const H2645NAL *nal, void *logctx)
835{
836    int i;
837    MMCO *mmco = sl->mmco;
838    int nb_mmco = 0;
839
840    if (nal->type == H264_NAL_IDR_SLICE) { // FIXME fields
841        skip_bits1(gb); // broken_link
842        if (get_bits1(gb)) {
843            mmco[0].opcode   = MMCO_LONG;
844            mmco[0].long_arg = 0;
845            nb_mmco          = 1;
846        }
847        sl->explicit_ref_marking = 1;
848    } else {
849        sl->explicit_ref_marking = get_bits1(gb);
850        if (sl->explicit_ref_marking) {
851            for (i = 0; i < FF_ARRAY_ELEMS(sl->mmco); i++) {
852                MMCOOpcode opcode = get_ue_golomb_31(gb);
853
854                mmco[i].opcode = opcode;
855                if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG) {
856                    mmco[i].short_pic_num =
857                        (sl->curr_pic_num - get_ue_golomb_long(gb) - 1) &
858                            (sl->max_pic_num - 1);
859                }
860                if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
861                    opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG) {
862                    unsigned int long_arg = get_ue_golomb_31(gb);
863                    if (long_arg >= 32 ||
864                        (long_arg >= 16 && !(opcode == MMCO_SET_MAX_LONG &&
865                                             long_arg == 16) &&
866                         !(opcode == MMCO_LONG2UNUSED && FIELD_PICTURE(sl)))) {
867                        av_log(logctx, AV_LOG_ERROR,
868                               "illegal long ref in memory management control "
869                               "operation %d\n", opcode);
870                        sl->nb_mmco = i;
871                        return -1;
872                    }
873                    mmco[i].long_arg = long_arg;
874                }
875
876                if (opcode > (unsigned) MMCO_LONG) {
877                    av_log(logctx, AV_LOG_ERROR,
878                           "illegal memory management control operation %d\n",
879                           opcode);
880                    sl->nb_mmco = i;
881                    return -1;
882                }
883                if (opcode == MMCO_END)
884                    break;
885            }
886            nb_mmco = i;
887        }
888    }
889
890    sl->nb_mmco = nb_mmco;
891
892    return 0;
893}
894