avformat/mxfdec: fix sorting of index segments
[ffmpeg.git] / libavcodec / h264_parser.c
1 /*
2  * H.26L/H.264/AVC/JVT/14496-10/... parser
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 parser.
25  * @author Michael Niedermayer <michaelni@gmx.at>
26  */
27
28 #define UNCHECKED_BITSTREAM_READER 1
29
30 #include <assert.h>
31 #include <stdint.h>
32
33 #include "libavutil/avutil.h"
34 #include "libavutil/error.h"
35 #include "libavutil/log.h"
36 #include "libavutil/mem.h"
37 #include "libavutil/pixfmt.h"
38
39 #include "avcodec.h"
40 #include "get_bits.h"
41 #include "golomb.h"
42 #include "h264.h"
43 #include "h264_sei.h"
44 #include "h264_ps.h"
45 #include "h264data.h"
46 #include "internal.h"
47 #include "mpegutils.h"
48 #include "parser.h"
49
50 typedef struct H264ParseContext {
51     ParseContext pc;
52     H264ParamSets ps;
53     H264DSPContext h264dsp;
54     H264POCContext poc;
55     H264SEIContext sei;
56     int is_avc;
57     int nal_length_size;
58     int got_first;
59     int picture_structure;
60     uint8_t parse_history[6];
61     int parse_history_count;
62     int parse_last_mb;
63     int64_t reference_dts;
64     int last_frame_num, last_picture_structure;
65 } H264ParseContext;
66
67
68 static int h264_find_frame_end(H264ParseContext *p, const uint8_t *buf,
69                                int buf_size, void *logctx)
70 {
71     int i, j;
72     uint32_t state;
73     ParseContext *pc = &p->pc;
74
75     int next_avc = p->is_avc ? 0 : buf_size;
76 //    mb_addr= pc->mb_addr - 1;
77     state = pc->state;
78     if (state > 13)
79         state = 7;
80
81     if (p->is_avc && !p->nal_length_size)
82         av_log(logctx, AV_LOG_ERROR, "AVC-parser: nal length size invalid\n");
83
84     for (i = 0; i < buf_size; i++) {
85         if (i >= next_avc) {
86             int nalsize = 0;
87             i = next_avc;
88             for (j = 0; j < p->nal_length_size; j++)
89                 nalsize = (nalsize << 8) | buf[i++];
90             if (nalsize <= 0 || nalsize > buf_size - i) {
91                 av_log(logctx, AV_LOG_ERROR, "AVC-parser: nal size %d remaining %d\n", nalsize, buf_size - i);
92                 return buf_size;
93             }
94             next_avc = i + nalsize;
95             state    = 5;
96         }
97
98         if (state == 7) {
99             i += p->h264dsp.startcode_find_candidate(buf + i, next_avc - i);
100             if (i < next_avc)
101                 state = 2;
102         } else if (state <= 2) {
103             if (buf[i] == 1)
104                 state ^= 5;            // 2->7, 1->4, 0->5
105             else if (buf[i])
106                 state = 7;
107             else
108                 state >>= 1;           // 2->1, 1->0, 0->0
109         } else if (state <= 5) {
110             int nalu_type = buf[i] & 0x1F;
111             if (nalu_type == H264_NAL_SEI || nalu_type == H264_NAL_SPS ||
112                 nalu_type == H264_NAL_PPS || nalu_type == H264_NAL_AUD) {
113                 if (pc->frame_start_found) {
114                     i++;
115                     goto found;
116                 }
117             } else if (nalu_type == H264_NAL_SLICE || nalu_type == H264_NAL_DPA ||
118                        nalu_type == H264_NAL_IDR_SLICE) {
119                 state += 8;
120                 continue;
121             }
122             state = 7;
123         } else {
124             p->parse_history[p->parse_history_count++] = buf[i];
125             if (p->parse_history_count > 5) {
126                 unsigned int mb, last_mb = p->parse_last_mb;
127                 GetBitContext gb;
128
129                 init_get_bits(&gb, p->parse_history, 8*p->parse_history_count);
130                 p->parse_history_count = 0;
131                 mb= get_ue_golomb_long(&gb);
132                 p->parse_last_mb = mb;
133                 if (pc->frame_start_found) {
134                     if (mb <= last_mb)
135                         goto found;
136                 } else
137                     pc->frame_start_found = 1;
138                 state = 7;
139             }
140         }
141     }
142     pc->state = state;
143     if (p->is_avc)
144         return next_avc;
145     return END_NOT_FOUND;
146
147 found:
148     pc->state             = 7;
149     pc->frame_start_found = 0;
150     if (p->is_avc)
151         return next_avc;
152     return i - (state & 5) - 5 * (state > 7);
153 }
154
155 static int scan_mmco_reset(AVCodecParserContext *s, GetBitContext *gb,
156                            void *logctx)
157 {
158     H264PredWeightTable pwt;
159     int slice_type_nos = s->pict_type & 3;
160     H264ParseContext *p = s->priv_data;
161     int list_count, ref_count[2];
162
163
164     if (p->ps.pps->redundant_pic_cnt_present)
165         get_ue_golomb(gb); // redundant_pic_count
166
167     if (slice_type_nos == AV_PICTURE_TYPE_B)
168         get_bits1(gb); // direct_spatial_mv_pred
169
170     if (ff_h264_parse_ref_count(&list_count, ref_count, gb, p->ps.pps,
171                                 slice_type_nos, p->picture_structure, logctx) < 0)
172         return AVERROR_INVALIDDATA;
173
174     if (slice_type_nos != AV_PICTURE_TYPE_I) {
175         int list;
176         for (list = 0; list < list_count; list++) {
177             if (get_bits1(gb)) {
178                 int index;
179                 for (index = 0; ; index++) {
180                     unsigned int reordering_of_pic_nums_idc = get_ue_golomb_31(gb);
181
182                     if (reordering_of_pic_nums_idc < 3)
183                         get_ue_golomb_long(gb);
184                     else if (reordering_of_pic_nums_idc > 3) {
185                         av_log(logctx, AV_LOG_ERROR,
186                                "illegal reordering_of_pic_nums_idc %d\n",
187                                reordering_of_pic_nums_idc);
188                         return AVERROR_INVALIDDATA;
189                     } else
190                         break;
191
192                     if (index >= ref_count[list]) {
193                         av_log(logctx, AV_LOG_ERROR,
194                                "reference count %d overflow\n", index);
195                         return AVERROR_INVALIDDATA;
196                     }
197                 }
198             }
199         }
200     }
201
202     if ((p->ps.pps->weighted_pred && slice_type_nos == AV_PICTURE_TYPE_P) ||
203         (p->ps.pps->weighted_bipred_idc == 1 && slice_type_nos == AV_PICTURE_TYPE_B))
204         ff_h264_pred_weight_table(gb, p->ps.sps, ref_count, slice_type_nos,
205                                   &pwt, p->picture_structure, logctx);
206
207     if (get_bits1(gb)) { // adaptive_ref_pic_marking_mode_flag
208         int i;
209         for (i = 0; i < MAX_MMCO_COUNT; i++) {
210             MMCOOpcode opcode = get_ue_golomb_31(gb);
211             if (opcode > (unsigned) MMCO_LONG) {
212                 av_log(logctx, AV_LOG_ERROR,
213                        "illegal memory management control operation %d\n",
214                        opcode);
215                 return AVERROR_INVALIDDATA;
216             }
217             if (opcode == MMCO_END)
218                return 0;
219             else if (opcode == MMCO_RESET)
220                 return 1;
221
222             if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG)
223                 get_ue_golomb_long(gb); // difference_of_pic_nums_minus1
224             if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
225                 opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG)
226                 get_ue_golomb_31(gb);
227         }
228     }
229
230     return 0;
231 }
232
233 /**
234  * Parse NAL units of found picture and decode some basic information.
235  *
236  * @param s parser context.
237  * @param avctx codec context.
238  * @param buf buffer with field/frame data.
239  * @param buf_size size of the buffer.
240  */
241 static inline int parse_nal_units(AVCodecParserContext *s,
242                                   AVCodecContext *avctx,
243                                   const uint8_t * const buf, int buf_size)
244 {
245     H264ParseContext *p = s->priv_data;
246     H2645RBSP rbsp = { NULL };
247     H2645NAL nal = { NULL };
248     int buf_index, next_avc;
249     unsigned int pps_id;
250     unsigned int slice_type;
251     int state = -1, got_reset = 0;
252     int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
253     int field_poc[2];
254     int ret;
255
256     /* set some sane default values */
257     s->pict_type         = AV_PICTURE_TYPE_I;
258     s->key_frame         = 0;
259     s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
260
261     ff_h264_sei_uninit(&p->sei);
262     p->sei.frame_packing.arrangement_cancel_flag = -1;
263
264     if (!buf_size)
265         return 0;
266
267     av_fast_padded_malloc(&rbsp.rbsp_buffer, &rbsp.rbsp_buffer_alloc_size, buf_size);
268     if (!rbsp.rbsp_buffer)
269         return AVERROR(ENOMEM);
270
271     buf_index     = 0;
272     next_avc      = p->is_avc ? 0 : buf_size;
273     for (;;) {
274         const SPS *sps;
275         int src_length, consumed, nalsize = 0;
276
277         if (buf_index >= next_avc) {
278             nalsize = get_nalsize(p->nal_length_size, buf, buf_size, &buf_index, avctx);
279             if (nalsize < 0)
280                 break;
281             next_avc = buf_index + nalsize;
282         } else {
283             buf_index = find_start_code(buf, buf_size, buf_index, next_avc);
284             if (buf_index >= buf_size)
285                 break;
286             if (buf_index >= next_avc)
287                 continue;
288         }
289         src_length = next_avc - buf_index;
290
291         state = buf[buf_index];
292         switch (state & 0x1f) {
293         case H264_NAL_SLICE:
294         case H264_NAL_IDR_SLICE:
295             // Do not walk the whole buffer just to decode slice header
296             if ((state & 0x1f) == H264_NAL_IDR_SLICE || ((state >> 5) & 0x3) == 0) {
297                 /* IDR or disposable slice
298                  * No need to decode many bytes because MMCOs shall not be present. */
299                 if (src_length > 60)
300                     src_length = 60;
301             } else {
302                 /* To decode up to MMCOs */
303                 if (src_length > 1000)
304                     src_length = 1000;
305             }
306             break;
307         }
308         consumed = ff_h2645_extract_rbsp(buf + buf_index, src_length, &rbsp, &nal, 1);
309         if (consumed < 0)
310             break;
311
312         buf_index += consumed;
313
314         ret = init_get_bits8(&nal.gb, nal.data, nal.size);
315         if (ret < 0)
316             goto fail;
317         get_bits1(&nal.gb);
318         nal.ref_idc = get_bits(&nal.gb, 2);
319         nal.type    = get_bits(&nal.gb, 5);
320
321         switch (nal.type) {
322         case H264_NAL_SPS:
323             ff_h264_decode_seq_parameter_set(&nal.gb, avctx, &p->ps, 0);
324             break;
325         case H264_NAL_PPS:
326             ff_h264_decode_picture_parameter_set(&nal.gb, avctx, &p->ps,
327                                                  nal.size_bits);
328             break;
329         case H264_NAL_SEI:
330             ff_h264_sei_decode(&p->sei, &nal.gb, &p->ps, avctx);
331             break;
332         case H264_NAL_IDR_SLICE:
333             s->key_frame = 1;
334
335             p->poc.prev_frame_num        = 0;
336             p->poc.prev_frame_num_offset = 0;
337             p->poc.prev_poc_msb          =
338             p->poc.prev_poc_lsb          = 0;
339         /* fall through */
340         case H264_NAL_SLICE:
341             get_ue_golomb_long(&nal.gb);  // skip first_mb_in_slice
342             slice_type   = get_ue_golomb_31(&nal.gb);
343             s->pict_type = ff_h264_golomb_to_pict_type[slice_type % 5];
344             if (p->sei.recovery_point.recovery_frame_cnt >= 0) {
345                 /* key frame, since recovery_frame_cnt is set */
346                 s->key_frame = 1;
347             }
348             pps_id = get_ue_golomb(&nal.gb);
349             if (pps_id >= MAX_PPS_COUNT) {
350                 av_log(avctx, AV_LOG_ERROR,
351                        "pps_id %u out of range\n", pps_id);
352                 goto fail;
353             }
354             if (!p->ps.pps_list[pps_id]) {
355                 av_log(avctx, AV_LOG_ERROR,
356                        "non-existing PPS %u referenced\n", pps_id);
357                 goto fail;
358             }
359
360             av_buffer_unref(&p->ps.pps_ref);
361             av_buffer_unref(&p->ps.sps_ref);
362             p->ps.pps = NULL;
363             p->ps.sps = NULL;
364             p->ps.pps_ref = av_buffer_ref(p->ps.pps_list[pps_id]);
365             if (!p->ps.pps_ref)
366                 goto fail;
367             p->ps.pps = (const PPS*)p->ps.pps_ref->data;
368
369             if (!p->ps.sps_list[p->ps.pps->sps_id]) {
370                 av_log(avctx, AV_LOG_ERROR,
371                        "non-existing SPS %u referenced\n", p->ps.pps->sps_id);
372                 goto fail;
373             }
374
375             p->ps.sps_ref = av_buffer_ref(p->ps.sps_list[p->ps.pps->sps_id]);
376             if (!p->ps.sps_ref)
377                 goto fail;
378             p->ps.sps = (const SPS*)p->ps.sps_ref->data;
379
380             sps = p->ps.sps;
381
382             // heuristic to detect non marked keyframes
383             if (p->ps.sps->ref_frame_count <= 1 && p->ps.pps->ref_count[0] <= 1 && s->pict_type == AV_PICTURE_TYPE_I)
384                 s->key_frame = 1;
385
386             p->poc.frame_num = get_bits(&nal.gb, sps->log2_max_frame_num);
387
388             s->coded_width  = 16 * sps->mb_width;
389             s->coded_height = 16 * sps->mb_height;
390             s->width        = s->coded_width  - (sps->crop_right + sps->crop_left);
391             s->height       = s->coded_height - (sps->crop_top   + sps->crop_bottom);
392             if (s->width <= 0 || s->height <= 0) {
393                 s->width  = s->coded_width;
394                 s->height = s->coded_height;
395             }
396
397             switch (sps->bit_depth_luma) {
398             case 9:
399                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P9;
400                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P9;
401                 else                                  s->format = AV_PIX_FMT_YUV420P9;
402                 break;
403             case 10:
404                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P10;
405                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P10;
406                 else                                  s->format = AV_PIX_FMT_YUV420P10;
407                 break;
408             case 8:
409                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P;
410                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P;
411                 else                                  s->format = AV_PIX_FMT_YUV420P;
412                 break;
413             default:
414                 s->format = AV_PIX_FMT_NONE;
415             }
416
417             avctx->profile = ff_h264_get_profile(sps);
418             avctx->level   = sps->level_idc;
419
420             if (sps->frame_mbs_only_flag) {
421                 p->picture_structure = PICT_FRAME;
422             } else {
423                 if (get_bits1(&nal.gb)) { // field_pic_flag
424                     p->picture_structure = PICT_TOP_FIELD + get_bits1(&nal.gb); // bottom_field_flag
425                 } else {
426                     p->picture_structure = PICT_FRAME;
427                 }
428             }
429
430             if (nal.type == H264_NAL_IDR_SLICE)
431                 get_ue_golomb_long(&nal.gb); /* idr_pic_id */
432             if (sps->poc_type == 0) {
433                 p->poc.poc_lsb = get_bits(&nal.gb, sps->log2_max_poc_lsb);
434
435                 if (p->ps.pps->pic_order_present == 1 &&
436                     p->picture_structure == PICT_FRAME)
437                     p->poc.delta_poc_bottom = get_se_golomb(&nal.gb);
438             }
439
440             if (sps->poc_type == 1 &&
441                 !sps->delta_pic_order_always_zero_flag) {
442                 p->poc.delta_poc[0] = get_se_golomb(&nal.gb);
443
444                 if (p->ps.pps->pic_order_present == 1 &&
445                     p->picture_structure == PICT_FRAME)
446                     p->poc.delta_poc[1] = get_se_golomb(&nal.gb);
447             }
448
449             /* Decode POC of this picture.
450              * The prev_ values needed for decoding POC of the next picture are not set here. */
451             field_poc[0] = field_poc[1] = INT_MAX;
452             ret = ff_h264_init_poc(field_poc, &s->output_picture_number, sps,
453                              &p->poc, p->picture_structure, nal.ref_idc);
454             if (ret < 0)
455                 goto fail;
456
457             /* Continue parsing to check if MMCO_RESET is present.
458              * FIXME: MMCO_RESET could appear in non-first slice.
459              *        Maybe, we should parse all undisposable non-IDR slice of this
460              *        picture until encountering MMCO_RESET in a slice of it. */
461             if (nal.ref_idc && nal.type != H264_NAL_IDR_SLICE) {
462                 got_reset = scan_mmco_reset(s, &nal.gb, avctx);
463                 if (got_reset < 0)
464                     goto fail;
465             }
466
467             /* Set up the prev_ values for decoding POC of the next picture. */
468             p->poc.prev_frame_num        = got_reset ? 0 : p->poc.frame_num;
469             p->poc.prev_frame_num_offset = got_reset ? 0 : p->poc.frame_num_offset;
470             if (nal.ref_idc != 0) {
471                 if (!got_reset) {
472                     p->poc.prev_poc_msb = p->poc.poc_msb;
473                     p->poc.prev_poc_lsb = p->poc.poc_lsb;
474                 } else {
475                     p->poc.prev_poc_msb = 0;
476                     p->poc.prev_poc_lsb =
477                         p->picture_structure == PICT_BOTTOM_FIELD ? 0 : field_poc[0];
478                 }
479             }
480
481             if (sps->pic_struct_present_flag && p->sei.picture_timing.present) {
482                 switch (p->sei.picture_timing.pic_struct) {
483                 case H264_SEI_PIC_STRUCT_TOP_FIELD:
484                 case H264_SEI_PIC_STRUCT_BOTTOM_FIELD:
485                     s->repeat_pict = 0;
486                     break;
487                 case H264_SEI_PIC_STRUCT_FRAME:
488                 case H264_SEI_PIC_STRUCT_TOP_BOTTOM:
489                 case H264_SEI_PIC_STRUCT_BOTTOM_TOP:
490                     s->repeat_pict = 1;
491                     break;
492                 case H264_SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
493                 case H264_SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
494                     s->repeat_pict = 2;
495                     break;
496                 case H264_SEI_PIC_STRUCT_FRAME_DOUBLING:
497                     s->repeat_pict = 3;
498                     break;
499                 case H264_SEI_PIC_STRUCT_FRAME_TRIPLING:
500                     s->repeat_pict = 5;
501                     break;
502                 default:
503                     s->repeat_pict = p->picture_structure == PICT_FRAME ? 1 : 0;
504                     break;
505                 }
506             } else {
507                 s->repeat_pict = p->picture_structure == PICT_FRAME ? 1 : 0;
508             }
509
510             if (p->picture_structure == PICT_FRAME) {
511                 s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
512                 if (sps->pic_struct_present_flag && p->sei.picture_timing.present) {
513                     switch (p->sei.picture_timing.pic_struct) {
514                     case H264_SEI_PIC_STRUCT_TOP_BOTTOM:
515                     case H264_SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
516                         s->field_order = AV_FIELD_TT;
517                         break;
518                     case H264_SEI_PIC_STRUCT_BOTTOM_TOP:
519                     case H264_SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
520                         s->field_order = AV_FIELD_BB;
521                         break;
522                     default:
523                         s->field_order = AV_FIELD_PROGRESSIVE;
524                         break;
525                     }
526                 } else {
527                     if (field_poc[0] < field_poc[1])
528                         s->field_order = AV_FIELD_TT;
529                     else if (field_poc[0] > field_poc[1])
530                         s->field_order = AV_FIELD_BB;
531                     else
532                         s->field_order = AV_FIELD_PROGRESSIVE;
533                 }
534             } else {
535                 if (p->picture_structure == PICT_TOP_FIELD)
536                     s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
537                 else
538                     s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
539                 if (p->poc.frame_num == p->last_frame_num &&
540                     p->last_picture_structure != AV_PICTURE_STRUCTURE_UNKNOWN &&
541                     p->last_picture_structure != AV_PICTURE_STRUCTURE_FRAME &&
542                     p->last_picture_structure != s->picture_structure) {
543                     if (p->last_picture_structure == AV_PICTURE_STRUCTURE_TOP_FIELD)
544                         s->field_order = AV_FIELD_TT;
545                     else
546                         s->field_order = AV_FIELD_BB;
547                 } else {
548                     s->field_order = AV_FIELD_UNKNOWN;
549                 }
550                 p->last_picture_structure = s->picture_structure;
551                 p->last_frame_num = p->poc.frame_num;
552             }
553
554             av_freep(&rbsp.rbsp_buffer);
555             return 0; /* no need to evaluate the rest */
556         }
557     }
558     if (q264) {
559         av_freep(&rbsp.rbsp_buffer);
560         return 0;
561     }
562     /* didn't find a picture! */
563     av_log(avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
564 fail:
565     av_freep(&rbsp.rbsp_buffer);
566     return -1;
567 }
568
569 static int h264_parse(AVCodecParserContext *s,
570                       AVCodecContext *avctx,
571                       const uint8_t **poutbuf, int *poutbuf_size,
572                       const uint8_t *buf, int buf_size)
573 {
574     H264ParseContext *p = s->priv_data;
575     ParseContext *pc = &p->pc;
576     int next;
577
578     if (!p->got_first) {
579         p->got_first = 1;
580         if (avctx->extradata_size) {
581             ff_h264_decode_extradata(avctx->extradata, avctx->extradata_size,
582                                      &p->ps, &p->is_avc, &p->nal_length_size,
583                                      avctx->err_recognition, avctx);
584         }
585     }
586
587     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
588         next = buf_size;
589     } else {
590         next = h264_find_frame_end(p, buf, buf_size, avctx);
591
592         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
593             *poutbuf      = NULL;
594             *poutbuf_size = 0;
595             return buf_size;
596         }
597
598         if (next < 0 && next != END_NOT_FOUND) {
599             av_assert1(pc->last_index + next >= 0);
600             h264_find_frame_end(p, &pc->buffer[pc->last_index + next], -next, avctx); // update state
601         }
602     }
603
604     parse_nal_units(s, avctx, buf, buf_size);
605
606     if (avctx->framerate.num)
607         avctx->time_base = av_inv_q(av_mul_q(avctx->framerate, (AVRational){avctx->ticks_per_frame, 1}));
608     if (p->sei.picture_timing.cpb_removal_delay >= 0) {
609         s->dts_sync_point    = p->sei.buffering_period.present;
610         s->dts_ref_dts_delta = p->sei.picture_timing.cpb_removal_delay;
611         s->pts_dts_delta     = p->sei.picture_timing.dpb_output_delay;
612     } else {
613         s->dts_sync_point    = INT_MIN;
614         s->dts_ref_dts_delta = INT_MIN;
615         s->pts_dts_delta     = INT_MIN;
616     }
617
618     if (s->flags & PARSER_FLAG_ONCE) {
619         s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
620     }
621
622     if (s->dts_sync_point >= 0) {
623         int64_t den = avctx->time_base.den * (int64_t)avctx->pkt_timebase.num;
624         if (den > 0) {
625             int64_t num = avctx->time_base.num * (int64_t)avctx->pkt_timebase.den;
626             if (s->dts != AV_NOPTS_VALUE) {
627                 // got DTS from the stream, update reference timestamp
628                 p->reference_dts = s->dts - av_rescale(s->dts_ref_dts_delta, num, den);
629             } else if (p->reference_dts != AV_NOPTS_VALUE) {
630                 // compute DTS based on reference timestamp
631                 s->dts = p->reference_dts + av_rescale(s->dts_ref_dts_delta, num, den);
632             }
633
634             if (p->reference_dts != AV_NOPTS_VALUE && s->pts == AV_NOPTS_VALUE)
635                 s->pts = s->dts + av_rescale(s->pts_dts_delta, num, den);
636
637             if (s->dts_sync_point > 0)
638                 p->reference_dts = s->dts; // new reference
639         }
640     }
641
642     *poutbuf      = buf;
643     *poutbuf_size = buf_size;
644     return next;
645 }
646
647 static int h264_split(AVCodecContext *avctx,
648                       const uint8_t *buf, int buf_size)
649 {
650     uint32_t state = -1;
651     int has_sps    = 0;
652     int has_pps    = 0;
653     const uint8_t *ptr = buf, *end = buf + buf_size;
654     int nalu_type;
655
656     while (ptr < end) {
657         ptr = avpriv_find_start_code(ptr, end, &state);
658         if ((state & 0xFFFFFF00) != 0x100)
659             break;
660         nalu_type = state & 0x1F;
661         if (nalu_type == H264_NAL_SPS) {
662             has_sps = 1;
663         } else if (nalu_type == H264_NAL_PPS)
664             has_pps = 1;
665         /* else if (nalu_type == 0x01 ||
666          *     nalu_type == 0x02 ||
667          *     nalu_type == 0x05) {
668          *  }
669          */
670         else if ((nalu_type != H264_NAL_SEI || has_pps) &&
671                   nalu_type != H264_NAL_AUD && nalu_type != H264_NAL_SPS_EXT &&
672                   nalu_type != 0x0f) {
673             if (has_sps) {
674                 while (ptr - 4 > buf && ptr[-5] == 0)
675                     ptr--;
676                 return ptr - 4 - buf;
677             }
678         }
679     }
680
681     return 0;
682 }
683
684 static void h264_close(AVCodecParserContext *s)
685 {
686     H264ParseContext *p = s->priv_data;
687     ParseContext *pc = &p->pc;
688
689     av_freep(&pc->buffer);
690
691     ff_h264_sei_uninit(&p->sei);
692     ff_h264_ps_uninit(&p->ps);
693 }
694
695 static av_cold int init(AVCodecParserContext *s)
696 {
697     H264ParseContext *p = s->priv_data;
698
699     p->reference_dts = AV_NOPTS_VALUE;
700     p->last_frame_num = INT_MAX;
701     ff_h264dsp_init(&p->h264dsp, 8, 1);
702     return 0;
703 }
704
705 AVCodecParser ff_h264_parser = {
706     .codec_ids      = { AV_CODEC_ID_H264 },
707     .priv_data_size = sizeof(H264ParseContext),
708     .parser_init    = init,
709     .parser_parse   = h264_parse,
710     .parser_close   = h264_close,
711     .split          = h264_split,
712 };