path: root/libavcodec/h264_parser.c (plain)
blob: aed0793b5162939e2205c3c89fcbf7e2ad566f91

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, 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	H2645NAL nal = { NULL };
247	int buf_index, next_avc;
248	unsigned int pps_id;
249	unsigned int slice_type;
250	int state = -1, got_reset = 0;
251	int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
252	int field_poc[2];
253	int ret;
254
255	/* set some sane default values */
256	s->pict_type = AV_PICTURE_TYPE_I;
257	s->key_frame = 0;
258	s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
259
260	ff_h264_sei_uninit(&p->sei);
261	p->sei.frame_packing.frame_packing_arrangement_cancel_flag = -1;
262
263	if (!buf_size)
264	return 0;
265
266	buf_index = 0;
267	next_avc = p->is_avc ? 0 : buf_size;
268	for (;;) {
269	const SPS *sps;
270	int src_length, consumed, nalsize = 0;
271
272	if (buf_index >= next_avc) {
273	nalsize = get_nalsize(p->nal_length_size, buf, buf_size, &buf_index, avctx);
274	if (nalsize < 0)
275	break;
276	next_avc = buf_index + nalsize;
277	} else {
278	buf_index = find_start_code(buf, buf_size, buf_index, next_avc);
279	if (buf_index >= buf_size)
280	break;
281	if (buf_index >= next_avc)
282	continue;
283	}
284	src_length = next_avc - buf_index;
285
286	state = buf[buf_index];
287	switch (state & 0x1f) {
288	case H264_NAL_SLICE:
289	case H264_NAL_IDR_SLICE:
290	// Do not walk the whole buffer just to decode slice header
291	if ((state & 0x1f) == H264_NAL_IDR_SLICE || ((state >> 5) & 0x3) == 0) {
292	/* IDR or disposable slice
293	* No need to decode many bytes because MMCOs shall not be present. */
294	if (src_length > 60)
295	src_length = 60;
296	} else {
297	/* To decode up to MMCOs */
298	if (src_length > 1000)
299	src_length = 1000;
300	}
301	break;
302	}
303	consumed = ff_h2645_extract_rbsp(buf + buf_index, src_length, &nal, 1);
304	if (consumed < 0)
305	break;
306
307	buf_index += consumed;
308
309	ret = init_get_bits8(&nal.gb, nal.data, nal.size);
310	if (ret < 0)
311	goto fail;
312	get_bits1(&nal.gb);
313	nal.ref_idc = get_bits(&nal.gb, 2);
314	nal.type = get_bits(&nal.gb, 5);
315
316	switch (nal.type) {
317	case H264_NAL_SPS:
318	ff_h264_decode_seq_parameter_set(&nal.gb, avctx, &p->ps, 0);
319	break;
320	case H264_NAL_PPS:
321	ff_h264_decode_picture_parameter_set(&nal.gb, avctx, &p->ps,
322	nal.size_bits);
323	break;
324	case H264_NAL_SEI:
325	ff_h264_sei_decode(&p->sei, &nal.gb, &p->ps, avctx);
326	break;
327	case H264_NAL_264_DV:
328	/*00 00 00 01 7c 01 19 08
329	nal type = 0x7c & 0x1f;
330	any conflict?
331	*/
332	avctx->has_dolby_vision_meta = 1;
333	break;
334	case H264_NAL_IDR_SLICE:
335	s->key_frame = 1;
336
337	p->poc.prev_frame_num = 0;
338	p->poc.prev_frame_num_offset = 0;
339	p->poc.prev_poc_msb =
340	p->poc.prev_poc_lsb = 0;
341	/* fall through */
342	case H264_NAL_SLICE:
343	get_ue_golomb_long(&nal.gb); // skip first_mb_in_slice
344	slice_type = get_ue_golomb_31(&nal.gb);
345	s->pict_type = ff_h264_golomb_to_pict_type[slice_type % 5];
346	if (p->sei.recovery_point.recovery_frame_cnt >= 0) {
347	/* key frame, since recovery_frame_cnt is set */
348	s->key_frame = 1;
349	}
350	pps_id = get_ue_golomb(&nal.gb);
351	if (pps_id >= MAX_PPS_COUNT) {
352	av_log(avctx, AV_LOG_ERROR,
353	"pps_id %u out of range\n", pps_id);
354	goto fail;
355	}
356	if (!p->ps.pps_list[pps_id]) {
357	av_log(avctx, AV_LOG_ERROR,
358	"non-existing PPS %u referenced\n", pps_id);
359	goto fail;
360	}
361
362	av_buffer_unref(&p->ps.pps_ref);
363	av_buffer_unref(&p->ps.sps_ref);
364	p->ps.pps = NULL;
365	p->ps.sps = NULL;
366	p->ps.pps_ref = av_buffer_ref(p->ps.pps_list[pps_id]);
367	if (!p->ps.pps_ref)
368	goto fail;
369	p->ps.pps = (const PPS*)p->ps.pps_ref->data;
370
371	if (!p->ps.sps_list[p->ps.pps->sps_id]) {
372	av_log(avctx, AV_LOG_ERROR,
373	"non-existing SPS %u referenced\n", p->ps.pps->sps_id);
374	goto fail;
375	}
376
377	p->ps.sps_ref = av_buffer_ref(p->ps.sps_list[p->ps.pps->sps_id]);
378	if (!p->ps.sps_ref)
379	goto fail;
380	p->ps.sps = (const SPS*)p->ps.sps_ref->data;
381
382	sps = p->ps.sps;
383
384	// heuristic to detect non marked keyframes
385	if (p->ps.sps->ref_frame_count <= 1 && p->ps.pps->ref_count[0] <= 1 && s->pict_type == AV_PICTURE_TYPE_I)
386	s->key_frame = 1;
387
388	p->poc.frame_num = get_bits(&nal.gb, sps->log2_max_frame_num);
389
390	s->coded_width = 16 * sps->mb_width;
391	s->coded_height = 16 * sps->mb_height;
392	s->width = s->coded_width - (sps->crop_right + sps->crop_left);
393	s->height = s->coded_height - (sps->crop_top + sps->crop_bottom);
394	if (s->width <= 0 || s->height <= 0) {
395	s->width = s->coded_width;
396	s->height = s->coded_height;
397	}
398
399	switch (sps->bit_depth_luma) {
400	case 9:
401	if (sps->chroma_format_idc == 3) s->format = AV_PIX_FMT_YUV444P9;
402	else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P9;
403	else s->format = AV_PIX_FMT_YUV420P9;
404	break;
405	case 10:
406	if (sps->chroma_format_idc == 3) s->format = AV_PIX_FMT_YUV444P10;
407	else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P10;
408	else s->format = AV_PIX_FMT_YUV420P10;
409	break;
410	case 8:
411	if (sps->chroma_format_idc == 3) s->format = AV_PIX_FMT_YUV444P;
412	else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P;
413	else s->format = AV_PIX_FMT_YUV420P;
414	break;
415	default:
416	s->format = AV_PIX_FMT_NONE;
417	}
418
419	avctx->profile = ff_h264_get_profile(sps);
420	avctx->level = sps->level_idc;
421
422	if (sps->frame_mbs_only_flag) {
423	p->picture_structure = PICT_FRAME;
424	} else {
425	if (get_bits1(&nal.gb)) { // field_pic_flag
426	p->picture_structure = PICT_TOP_FIELD + get_bits1(&nal.gb); // bottom_field_flag
427	} else {
428	p->picture_structure = PICT_FRAME;
429	}
430	}
431
432	if (nal.type == H264_NAL_IDR_SLICE)
433	get_ue_golomb_long(&nal.gb); /* idr_pic_id */
434	if (sps->poc_type == 0) {
435	p->poc.poc_lsb = get_bits(&nal.gb, sps->log2_max_poc_lsb);
436
437	if (p->ps.pps->pic_order_present == 1 &&
438	p->picture_structure == PICT_FRAME)
439	p->poc.delta_poc_bottom = get_se_golomb(&nal.gb);
440	}
441
442	if (sps->poc_type == 1 &&
443	!sps->delta_pic_order_always_zero_flag) {
444	p->poc.delta_poc[0] = get_se_golomb(&nal.gb);
445
446	if (p->ps.pps->pic_order_present == 1 &&
447	p->picture_structure == PICT_FRAME)
448	p->poc.delta_poc[1] = get_se_golomb(&nal.gb);
449	}
450
451	/* Decode POC of this picture.
452	* The prev_ values needed for decoding POC of the next picture are not set here. */
453	field_poc[0] = field_poc[1] = INT_MAX;
454	ff_h264_init_poc(field_poc, &s->output_picture_number, sps,
455	&p->poc, p->picture_structure, nal.ref_idc);
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 SEI_PIC_STRUCT_TOP_FIELD:
484	case SEI_PIC_STRUCT_BOTTOM_FIELD:
485	s->repeat_pict = 0;
486	break;
487	case SEI_PIC_STRUCT_FRAME:
488	case SEI_PIC_STRUCT_TOP_BOTTOM:
489	case SEI_PIC_STRUCT_BOTTOM_TOP:
490	s->repeat_pict = 1;
491	break;
492	case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
493	case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
494	s->repeat_pict = 2;
495	break;
496	case SEI_PIC_STRUCT_FRAME_DOUBLING:
497	s->repeat_pict = 3;
498	break;
499	case 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 SEI_PIC_STRUCT_TOP_BOTTOM:
515	case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
516	s->field_order = AV_FIELD_TT;
517	break;
518	case SEI_PIC_STRUCT_BOTTOM_TOP:
519	case 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(&nal.rbsp_buffer);
555	return 0; /* no need to evaluate the rest */
556	}
557	}
558	if (q264) {
559	av_freep(&nal.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(&nal.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	};
713