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