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Merge commit '2eeac79936e83c4495cbe5905064ab797e9b45ff'
[ffmpeg] / 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             unsigned int mb, last_mb = p->parse_last_mb;
125             GetBitContext gb;
126             p->parse_history[p->parse_history_count++] = buf[i];
127
128             init_get_bits(&gb, p->parse_history, 8*p->parse_history_count);
129             mb= get_ue_golomb_long(&gb);
130             if (get_bits_left(&gb) > 0 || p->parse_history_count > 5) {
131                 p->parse_last_mb = mb;
132                 if (pc->frame_start_found) {
133                     if (mb <= last_mb) {
134                         i -= p->parse_history_count - 1;
135                         p->parse_history_count = 0;
136                         goto found;
137                     }
138                 } else
139                     pc->frame_start_found = 1;
140                 p->parse_history_count = 0;
141                 state = 7;
142             }
143         }
144     }
145     pc->state = state;
146     if (p->is_avc)
147         return next_avc;
148     return END_NOT_FOUND;
149
150 found:
151     pc->state             = 7;
152     pc->frame_start_found = 0;
153     if (p->is_avc)
154         return next_avc;
155     return i - (state & 5);
156 }
157
158 static int scan_mmco_reset(AVCodecParserContext *s, GetBitContext *gb,
159                            void *logctx)
160 {
161     H264PredWeightTable pwt;
162     int slice_type_nos = s->pict_type & 3;
163     H264ParseContext *p = s->priv_data;
164     int list_count, ref_count[2];
165
166
167     if (p->ps.pps->redundant_pic_cnt_present)
168         get_ue_golomb(gb); // redundant_pic_count
169
170     if (slice_type_nos == AV_PICTURE_TYPE_B)
171         get_bits1(gb); // direct_spatial_mv_pred
172
173     if (ff_h264_parse_ref_count(&list_count, ref_count, gb, p->ps.pps,
174                                 slice_type_nos, p->picture_structure, logctx) < 0)
175         return AVERROR_INVALIDDATA;
176
177     if (slice_type_nos != AV_PICTURE_TYPE_I) {
178         int list;
179         for (list = 0; list < list_count; list++) {
180             if (get_bits1(gb)) {
181                 int index;
182                 for (index = 0; ; index++) {
183                     unsigned int reordering_of_pic_nums_idc = get_ue_golomb_31(gb);
184
185                     if (reordering_of_pic_nums_idc < 3)
186                         get_ue_golomb_long(gb);
187                     else if (reordering_of_pic_nums_idc > 3) {
188                         av_log(logctx, AV_LOG_ERROR,
189                                "illegal reordering_of_pic_nums_idc %d\n",
190                                reordering_of_pic_nums_idc);
191                         return AVERROR_INVALIDDATA;
192                     } else
193                         break;
194
195                     if (index >= ref_count[list]) {
196                         av_log(logctx, AV_LOG_ERROR,
197                                "reference count %d overflow\n", index);
198                         return AVERROR_INVALIDDATA;
199                     }
200                 }
201             }
202         }
203     }
204
205     if ((p->ps.pps->weighted_pred && slice_type_nos == AV_PICTURE_TYPE_P) ||
206         (p->ps.pps->weighted_bipred_idc == 1 && slice_type_nos == AV_PICTURE_TYPE_B))
207         ff_h264_pred_weight_table(gb, p->ps.sps, ref_count, slice_type_nos,
208                                   &pwt, p->picture_structure, logctx);
209
210     if (get_bits1(gb)) { // adaptive_ref_pic_marking_mode_flag
211         int i;
212         for (i = 0; i < MAX_MMCO_COUNT; i++) {
213             MMCOOpcode opcode = get_ue_golomb_31(gb);
214             if (opcode > (unsigned) MMCO_LONG) {
215                 av_log(logctx, AV_LOG_ERROR,
216                        "illegal memory management control operation %d\n",
217                        opcode);
218                 return AVERROR_INVALIDDATA;
219             }
220             if (opcode == MMCO_END)
221                return 0;
222             else if (opcode == MMCO_RESET)
223                 return 1;
224
225             if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG)
226                 get_ue_golomb_long(gb); // difference_of_pic_nums_minus1
227             if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
228                 opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG)
229                 get_ue_golomb_31(gb);
230         }
231     }
232
233     return 0;
234 }
235
236 /**
237  * Parse NAL units of found picture and decode some basic information.
238  *
239  * @param s parser context.
240  * @param avctx codec context.
241  * @param buf buffer with field/frame data.
242  * @param buf_size size of the buffer.
243  */
244 static inline int parse_nal_units(AVCodecParserContext *s,
245                                   AVCodecContext *avctx,
246                                   const uint8_t * const buf, int buf_size)
247 {
248     H264ParseContext *p = s->priv_data;
249     H2645RBSP rbsp = { NULL };
250     H2645NAL nal = { NULL };
251     int buf_index, next_avc;
252     unsigned int pps_id;
253     unsigned int slice_type;
254     int state = -1, got_reset = 0;
255     int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
256     int field_poc[2];
257     int ret;
258
259     /* set some sane default values */
260     s->pict_type         = AV_PICTURE_TYPE_I;
261     s->key_frame         = 0;
262     s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
263
264     ff_h264_sei_uninit(&p->sei);
265     p->sei.frame_packing.arrangement_cancel_flag = -1;
266
267     if (!buf_size)
268         return 0;
269
270     av_fast_padded_malloc(&rbsp.rbsp_buffer, &rbsp.rbsp_buffer_alloc_size, buf_size);
271     if (!rbsp.rbsp_buffer)
272         return AVERROR(ENOMEM);
273
274     buf_index     = 0;
275     next_avc      = p->is_avc ? 0 : buf_size;
276     for (;;) {
277         const SPS *sps;
278         int src_length, consumed, nalsize = 0;
279
280         if (buf_index >= next_avc) {
281             nalsize = get_nalsize(p->nal_length_size, buf, buf_size, &buf_index, avctx);
282             if (nalsize < 0)
283                 break;
284             next_avc = buf_index + nalsize;
285         } else {
286             buf_index = find_start_code(buf, buf_size, buf_index, next_avc);
287             if (buf_index >= buf_size)
288                 break;
289             if (buf_index >= next_avc)
290                 continue;
291         }
292         src_length = next_avc - buf_index;
293
294         state = buf[buf_index];
295         switch (state & 0x1f) {
296         case H264_NAL_SLICE:
297         case H264_NAL_IDR_SLICE:
298             // Do not walk the whole buffer just to decode slice header
299             if ((state & 0x1f) == H264_NAL_IDR_SLICE || ((state >> 5) & 0x3) == 0) {
300                 /* IDR or disposable slice
301                  * No need to decode many bytes because MMCOs shall not be present. */
302                 if (src_length > 60)
303                     src_length = 60;
304             } else {
305                 /* To decode up to MMCOs */
306                 if (src_length > 1000)
307                     src_length = 1000;
308             }
309             break;
310         }
311         consumed = ff_h2645_extract_rbsp(buf + buf_index, src_length, &rbsp, &nal, 1);
312         if (consumed < 0)
313             break;
314
315         buf_index += consumed;
316
317         ret = init_get_bits8(&nal.gb, nal.data, nal.size);
318         if (ret < 0)
319             goto fail;
320         get_bits1(&nal.gb);
321         nal.ref_idc = get_bits(&nal.gb, 2);
322         nal.type    = get_bits(&nal.gb, 5);
323
324         switch (nal.type) {
325         case H264_NAL_SPS:
326             ff_h264_decode_seq_parameter_set(&nal.gb, avctx, &p->ps, 0);
327             break;
328         case H264_NAL_PPS:
329             ff_h264_decode_picture_parameter_set(&nal.gb, avctx, &p->ps,
330                                                  nal.size_bits);
331             break;
332         case H264_NAL_SEI:
333             ff_h264_sei_decode(&p->sei, &nal.gb, &p->ps, avctx);
334             break;
335         case H264_NAL_IDR_SLICE:
336             s->key_frame = 1;
337
338             p->poc.prev_frame_num        = 0;
339             p->poc.prev_frame_num_offset = 0;
340             p->poc.prev_poc_msb          =
341             p->poc.prev_poc_lsb          = 0;
342         /* fall through */
343         case H264_NAL_SLICE:
344             get_ue_golomb_long(&nal.gb);  // skip first_mb_in_slice
345             slice_type   = get_ue_golomb_31(&nal.gb);
346             s->pict_type = ff_h264_golomb_to_pict_type[slice_type % 5];
347             if (p->sei.recovery_point.recovery_frame_cnt >= 0) {
348                 /* key frame, since recovery_frame_cnt is set */
349                 s->key_frame = 1;
350             }
351             pps_id = get_ue_golomb(&nal.gb);
352             if (pps_id >= MAX_PPS_COUNT) {
353                 av_log(avctx, AV_LOG_ERROR,
354                        "pps_id %u out of range\n", pps_id);
355                 goto fail;
356             }
357             if (!p->ps.pps_list[pps_id]) {
358                 av_log(avctx, AV_LOG_ERROR,
359                        "non-existing PPS %u referenced\n", pps_id);
360                 goto fail;
361             }
362
363             av_buffer_unref(&p->ps.pps_ref);
364             av_buffer_unref(&p->ps.sps_ref);
365             p->ps.pps = NULL;
366             p->ps.sps = NULL;
367             p->ps.pps_ref = av_buffer_ref(p->ps.pps_list[pps_id]);
368             if (!p->ps.pps_ref)
369                 goto fail;
370             p->ps.pps = (const PPS*)p->ps.pps_ref->data;
371
372             if (!p->ps.sps_list[p->ps.pps->sps_id]) {
373                 av_log(avctx, AV_LOG_ERROR,
374                        "non-existing SPS %u referenced\n", p->ps.pps->sps_id);
375                 goto fail;
376             }
377
378             p->ps.sps_ref = av_buffer_ref(p->ps.sps_list[p->ps.pps->sps_id]);
379             if (!p->ps.sps_ref)
380                 goto fail;
381             p->ps.sps = (const SPS*)p->ps.sps_ref->data;
382
383             sps = p->ps.sps;
384
385             // heuristic to detect non marked keyframes
386             if (p->ps.sps->ref_frame_count <= 1 && p->ps.pps->ref_count[0] <= 1 && s->pict_type == AV_PICTURE_TYPE_I)
387                 s->key_frame = 1;
388
389             p->poc.frame_num = get_bits(&nal.gb, sps->log2_max_frame_num);
390
391             s->coded_width  = 16 * sps->mb_width;
392             s->coded_height = 16 * sps->mb_height;
393             s->width        = s->coded_width  - (sps->crop_right + sps->crop_left);
394             s->height       = s->coded_height - (sps->crop_top   + sps->crop_bottom);
395             if (s->width <= 0 || s->height <= 0) {
396                 s->width  = s->coded_width;
397                 s->height = s->coded_height;
398             }
399
400             switch (sps->bit_depth_luma) {
401             case 9:
402                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P9;
403                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P9;
404                 else                                  s->format = AV_PIX_FMT_YUV420P9;
405                 break;
406             case 10:
407                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P10;
408                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P10;
409                 else                                  s->format = AV_PIX_FMT_YUV420P10;
410                 break;
411             case 8:
412                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P;
413                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P;
414                 else                                  s->format = AV_PIX_FMT_YUV420P;
415                 break;
416             default:
417                 s->format = AV_PIX_FMT_NONE;
418             }
419
420             avctx->profile = ff_h264_get_profile(sps);
421             avctx->level   = sps->level_idc;
422
423             if (sps->frame_mbs_only_flag) {
424                 p->picture_structure = PICT_FRAME;
425             } else {
426                 if (get_bits1(&nal.gb)) { // field_pic_flag
427                     p->picture_structure = PICT_TOP_FIELD + get_bits1(&nal.gb); // bottom_field_flag
428                 } else {
429                     p->picture_structure = PICT_FRAME;
430                 }
431             }
432
433             if (nal.type == H264_NAL_IDR_SLICE)
434                 get_ue_golomb_long(&nal.gb); /* idr_pic_id */
435             if (sps->poc_type == 0) {
436                 p->poc.poc_lsb = get_bits(&nal.gb, sps->log2_max_poc_lsb);
437
438                 if (p->ps.pps->pic_order_present == 1 &&
439                     p->picture_structure == PICT_FRAME)
440                     p->poc.delta_poc_bottom = get_se_golomb(&nal.gb);
441             }
442
443             if (sps->poc_type == 1 &&
444                 !sps->delta_pic_order_always_zero_flag) {
445                 p->poc.delta_poc[0] = get_se_golomb(&nal.gb);
446
447                 if (p->ps.pps->pic_order_present == 1 &&
448                     p->picture_structure == PICT_FRAME)
449                     p->poc.delta_poc[1] = get_se_golomb(&nal.gb);
450             }
451
452             /* Decode POC of this picture.
453              * The prev_ values needed for decoding POC of the next picture are not set here. */
454             field_poc[0] = field_poc[1] = INT_MAX;
455             ret = ff_h264_init_poc(field_poc, &s->output_picture_number, sps,
456                              &p->poc, p->picture_structure, nal.ref_idc);
457             if (ret < 0)
458                 goto fail;
459
460             /* Continue parsing to check if MMCO_RESET is present.
461              * FIXME: MMCO_RESET could appear in non-first slice.
462              *        Maybe, we should parse all undisposable non-IDR slice of this
463              *        picture until encountering MMCO_RESET in a slice of it. */
464             if (nal.ref_idc && nal.type != H264_NAL_IDR_SLICE) {
465                 got_reset = scan_mmco_reset(s, &nal.gb, avctx);
466                 if (got_reset < 0)
467                     goto fail;
468             }
469
470             /* Set up the prev_ values for decoding POC of the next picture. */
471             p->poc.prev_frame_num        = got_reset ? 0 : p->poc.frame_num;
472             p->poc.prev_frame_num_offset = got_reset ? 0 : p->poc.frame_num_offset;
473             if (nal.ref_idc != 0) {
474                 if (!got_reset) {
475                     p->poc.prev_poc_msb = p->poc.poc_msb;
476                     p->poc.prev_poc_lsb = p->poc.poc_lsb;
477                 } else {
478                     p->poc.prev_poc_msb = 0;
479                     p->poc.prev_poc_lsb =
480                         p->picture_structure == PICT_BOTTOM_FIELD ? 0 : field_poc[0];
481                 }
482             }
483
484             if (sps->pic_struct_present_flag && p->sei.picture_timing.present) {
485                 switch (p->sei.picture_timing.pic_struct) {
486                 case H264_SEI_PIC_STRUCT_TOP_FIELD:
487                 case H264_SEI_PIC_STRUCT_BOTTOM_FIELD:
488                     s->repeat_pict = 0;
489                     break;
490                 case H264_SEI_PIC_STRUCT_FRAME:
491                 case H264_SEI_PIC_STRUCT_TOP_BOTTOM:
492                 case H264_SEI_PIC_STRUCT_BOTTOM_TOP:
493                     s->repeat_pict = 1;
494                     break;
495                 case H264_SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
496                 case H264_SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
497                     s->repeat_pict = 2;
498                     break;
499                 case H264_SEI_PIC_STRUCT_FRAME_DOUBLING:
500                     s->repeat_pict = 3;
501                     break;
502                 case H264_SEI_PIC_STRUCT_FRAME_TRIPLING:
503                     s->repeat_pict = 5;
504                     break;
505                 default:
506                     s->repeat_pict = p->picture_structure == PICT_FRAME ? 1 : 0;
507                     break;
508                 }
509             } else {
510                 s->repeat_pict = p->picture_structure == PICT_FRAME ? 1 : 0;
511             }
512
513             if (p->picture_structure == PICT_FRAME) {
514                 s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
515                 if (sps->pic_struct_present_flag && p->sei.picture_timing.present) {
516                     switch (p->sei.picture_timing.pic_struct) {
517                     case H264_SEI_PIC_STRUCT_TOP_BOTTOM:
518                     case H264_SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
519                         s->field_order = AV_FIELD_TT;
520                         break;
521                     case H264_SEI_PIC_STRUCT_BOTTOM_TOP:
522                     case H264_SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
523                         s->field_order = AV_FIELD_BB;
524                         break;
525                     default:
526                         s->field_order = AV_FIELD_PROGRESSIVE;
527                         break;
528                     }
529                 } else {
530                     if (field_poc[0] < field_poc[1])
531                         s->field_order = AV_FIELD_TT;
532                     else if (field_poc[0] > field_poc[1])
533                         s->field_order = AV_FIELD_BB;
534                     else
535                         s->field_order = AV_FIELD_PROGRESSIVE;
536                 }
537             } else {
538                 if (p->picture_structure == PICT_TOP_FIELD)
539                     s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
540                 else
541                     s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
542                 if (p->poc.frame_num == p->last_frame_num &&
543                     p->last_picture_structure != AV_PICTURE_STRUCTURE_UNKNOWN &&
544                     p->last_picture_structure != AV_PICTURE_STRUCTURE_FRAME &&
545                     p->last_picture_structure != s->picture_structure) {
546                     if (p->last_picture_structure == AV_PICTURE_STRUCTURE_TOP_FIELD)
547                         s->field_order = AV_FIELD_TT;
548                     else
549                         s->field_order = AV_FIELD_BB;
550                 } else {
551                     s->field_order = AV_FIELD_UNKNOWN;
552                 }
553                 p->last_picture_structure = s->picture_structure;
554                 p->last_frame_num = p->poc.frame_num;
555             }
556
557             av_freep(&rbsp.rbsp_buffer);
558             return 0; /* no need to evaluate the rest */
559         }
560     }
561     if (q264) {
562         av_freep(&rbsp.rbsp_buffer);
563         return 0;
564     }
565     /* didn't find a picture! */
566     av_log(avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
567 fail:
568     av_freep(&rbsp.rbsp_buffer);
569     return -1;
570 }
571
572 static int h264_parse(AVCodecParserContext *s,
573                       AVCodecContext *avctx,
574                       const uint8_t **poutbuf, int *poutbuf_size,
575                       const uint8_t *buf, int buf_size)
576 {
577     H264ParseContext *p = s->priv_data;
578     ParseContext *pc = &p->pc;
579     int next;
580
581     if (!p->got_first) {
582         p->got_first = 1;
583         if (avctx->extradata_size) {
584             ff_h264_decode_extradata(avctx->extradata, avctx->extradata_size,
585                                      &p->ps, &p->is_avc, &p->nal_length_size,
586                                      avctx->err_recognition, avctx);
587         }
588     }
589
590     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
591         next = buf_size;
592     } else {
593         next = h264_find_frame_end(p, buf, buf_size, avctx);
594
595         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
596             *poutbuf      = NULL;
597             *poutbuf_size = 0;
598             return buf_size;
599         }
600
601         if (next < 0 && next != END_NOT_FOUND) {
602             av_assert1(pc->last_index + next >= 0);
603             h264_find_frame_end(p, &pc->buffer[pc->last_index + next], -next, avctx); // update state
604         }
605     }
606
607     parse_nal_units(s, avctx, buf, buf_size);
608
609     if (avctx->framerate.num)
610         avctx->time_base = av_inv_q(av_mul_q(avctx->framerate, (AVRational){avctx->ticks_per_frame, 1}));
611     if (p->sei.picture_timing.cpb_removal_delay >= 0) {
612         s->dts_sync_point    = p->sei.buffering_period.present;
613         s->dts_ref_dts_delta = p->sei.picture_timing.cpb_removal_delay;
614         s->pts_dts_delta     = p->sei.picture_timing.dpb_output_delay;
615     } else {
616         s->dts_sync_point    = INT_MIN;
617         s->dts_ref_dts_delta = INT_MIN;
618         s->pts_dts_delta     = INT_MIN;
619     }
620
621     if (s->flags & PARSER_FLAG_ONCE) {
622         s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
623     }
624
625     if (s->dts_sync_point >= 0) {
626         int64_t den = avctx->time_base.den * (int64_t)avctx->pkt_timebase.num;
627         if (den > 0) {
628             int64_t num = avctx->time_base.num * (int64_t)avctx->pkt_timebase.den;
629             if (s->dts != AV_NOPTS_VALUE) {
630                 // got DTS from the stream, update reference timestamp
631                 p->reference_dts = s->dts - av_rescale(s->dts_ref_dts_delta, num, den);
632             } else if (p->reference_dts != AV_NOPTS_VALUE) {
633                 // compute DTS based on reference timestamp
634                 s->dts = p->reference_dts + av_rescale(s->dts_ref_dts_delta, num, den);
635             }
636
637             if (p->reference_dts != AV_NOPTS_VALUE && s->pts == AV_NOPTS_VALUE)
638                 s->pts = s->dts + av_rescale(s->pts_dts_delta, num, den);
639
640             if (s->dts_sync_point > 0)
641                 p->reference_dts = s->dts; // new reference
642         }
643     }
644
645     *poutbuf      = buf;
646     *poutbuf_size = buf_size;
647     return next;
648 }
649
650 static int h264_split(AVCodecContext *avctx,
651                       const uint8_t *buf, int buf_size)
652 {
653     uint32_t state = -1;
654     int has_sps    = 0;
655     int has_pps    = 0;
656     const uint8_t *ptr = buf, *end = buf + buf_size;
657     int nalu_type;
658
659     while (ptr < end) {
660         ptr = avpriv_find_start_code(ptr, end, &state);
661         if ((state & 0xFFFFFF00) != 0x100)
662             break;
663         nalu_type = state & 0x1F;
664         if (nalu_type == H264_NAL_SPS) {
665             has_sps = 1;
666         } else if (nalu_type == H264_NAL_PPS)
667             has_pps = 1;
668         /* else if (nalu_type == 0x01 ||
669          *     nalu_type == 0x02 ||
670          *     nalu_type == 0x05) {
671          *  }
672          */
673         else if ((nalu_type != H264_NAL_SEI || has_pps) &&
674                   nalu_type != H264_NAL_AUD && nalu_type != H264_NAL_SPS_EXT &&
675                   nalu_type != 0x0f) {
676             if (has_sps) {
677                 while (ptr - 4 > buf && ptr[-5] == 0)
678                     ptr--;
679                 return ptr - 4 - buf;
680             }
681         }
682     }
683
684     return 0;
685 }
686
687 static void h264_close(AVCodecParserContext *s)
688 {
689     H264ParseContext *p = s->priv_data;
690     ParseContext *pc = &p->pc;
691
692     av_freep(&pc->buffer);
693
694     ff_h264_sei_uninit(&p->sei);
695     ff_h264_ps_uninit(&p->ps);
696 }
697
698 static av_cold int init(AVCodecParserContext *s)
699 {
700     H264ParseContext *p = s->priv_data;
701
702     p->reference_dts = AV_NOPTS_VALUE;
703     p->last_frame_num = INT_MAX;
704     ff_h264dsp_init(&p->h264dsp, 8, 1);
705     return 0;
706 }
707
708 AVCodecParser ff_h264_parser = {
709     .codec_ids      = { AV_CODEC_ID_H264 },
710     .priv_data_size = sizeof(H264ParseContext),
711     .parser_init    = init,
712     .parser_parse   = h264_parse,
713     .parser_close   = h264_close,
714     .split          = h264_split,
715 };