615884fdacffd5dd4b92573f1f5e7aa7d8ab9247
[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 } H264ParseContext;
64
65
66 static int h264_find_frame_end(H264ParseContext *p, const uint8_t *buf,
67                                int buf_size, void *logctx)
68 {
69     int i, j;
70     uint32_t state;
71     ParseContext *pc = &p->pc;
72
73     int next_avc = p->is_avc ? 0 : buf_size;
74 //    mb_addr= pc->mb_addr - 1;
75     state = pc->state;
76     if (state > 13)
77         state = 7;
78
79     if (p->is_avc && !p->nal_length_size)
80         av_log(logctx, AV_LOG_ERROR, "AVC-parser: nal length size invalid\n");
81
82     for (i = 0; i < buf_size; i++) {
83         if (i >= next_avc) {
84             int nalsize = 0;
85             i = next_avc;
86             for (j = 0; j < p->nal_length_size; j++)
87                 nalsize = (nalsize << 8) | buf[i++];
88             if (nalsize <= 0 || nalsize > buf_size - i) {
89                 av_log(logctx, AV_LOG_ERROR, "AVC-parser: nal size %d remaining %d\n", nalsize, buf_size - i);
90                 return buf_size;
91             }
92             next_avc = i + nalsize;
93             state    = 5;
94         }
95
96         if (state == 7) {
97             i += p->h264dsp.startcode_find_candidate(buf + i, next_avc - i);
98             if (i < next_avc)
99                 state = 2;
100         } else if (state <= 2) {
101             if (buf[i] == 1)
102                 state ^= 5;            // 2->7, 1->4, 0->5
103             else if (buf[i])
104                 state = 7;
105             else
106                 state >>= 1;           // 2->1, 1->0, 0->0
107         } else if (state <= 5) {
108             int nalu_type = buf[i] & 0x1F;
109             if (nalu_type == H264_NAL_SEI || nalu_type == H264_NAL_SPS ||
110                 nalu_type == H264_NAL_PPS || nalu_type == H264_NAL_AUD) {
111                 if (pc->frame_start_found) {
112                     i++;
113                     goto found;
114                 }
115             } else if (nalu_type == H264_NAL_SLICE || nalu_type == H264_NAL_DPA ||
116                        nalu_type == H264_NAL_IDR_SLICE) {
117                 state += 8;
118                 continue;
119             }
120             state = 7;
121         } else {
122             p->parse_history[p->parse_history_count++] = buf[i];
123             if (p->parse_history_count > 5) {
124                 unsigned int mb, last_mb = p->parse_last_mb;
125                 GetBitContext gb;
126
127                 init_get_bits(&gb, p->parse_history, 8*p->parse_history_count);
128                 p->parse_history_count = 0;
129                 mb= get_ue_golomb_long(&gb);
130                 p->parse_last_mb = mb;
131                 if (pc->frame_start_found) {
132                     if (mb <= last_mb)
133                         goto found;
134                 } else
135                     pc->frame_start_found = 1;
136                 state = 7;
137             }
138         }
139     }
140     pc->state = state;
141     if (p->is_avc)
142         return next_avc;
143     return END_NOT_FOUND;
144
145 found:
146     pc->state             = 7;
147     pc->frame_start_found = 0;
148     if (p->is_avc)
149         return next_avc;
150     return i - (state & 5) - 5 * (state > 7);
151 }
152
153 static int scan_mmco_reset(AVCodecParserContext *s, GetBitContext *gb,
154                            void *logctx)
155 {
156     H264PredWeightTable pwt;
157     int slice_type_nos = s->pict_type & 3;
158     H264ParseContext *p = s->priv_data;
159     int list_count, ref_count[2];
160
161
162     if (p->ps.pps->redundant_pic_cnt_present)
163         get_ue_golomb(gb); // redundant_pic_count
164
165     if (slice_type_nos == AV_PICTURE_TYPE_B)
166         get_bits1(gb); // direct_spatial_mv_pred
167
168     if (ff_h264_parse_ref_count(&list_count, ref_count, gb, p->ps.pps,
169                                 slice_type_nos, p->picture_structure, logctx) < 0)
170         return AVERROR_INVALIDDATA;
171
172     if (slice_type_nos != AV_PICTURE_TYPE_I) {
173         int list;
174         for (list = 0; list < list_count; list++) {
175             if (get_bits1(gb)) {
176                 int index;
177                 for (index = 0; ; index++) {
178                     unsigned int reordering_of_pic_nums_idc = get_ue_golomb_31(gb);
179
180                     if (reordering_of_pic_nums_idc < 3)
181                         get_ue_golomb_long(gb);
182                     else if (reordering_of_pic_nums_idc > 3) {
183                         av_log(logctx, AV_LOG_ERROR,
184                                "illegal reordering_of_pic_nums_idc %d\n",
185                                reordering_of_pic_nums_idc);
186                         return AVERROR_INVALIDDATA;
187                     } else
188                         break;
189
190                     if (index >= ref_count[list]) {
191                         av_log(logctx, AV_LOG_ERROR,
192                                "reference count %d overflow\n", index);
193                         return AVERROR_INVALIDDATA;
194                     }
195                 }
196             }
197         }
198     }
199
200     if ((p->ps.pps->weighted_pred && slice_type_nos == AV_PICTURE_TYPE_P) ||
201         (p->ps.pps->weighted_bipred_idc == 1 && slice_type_nos == AV_PICTURE_TYPE_B))
202         ff_h264_pred_weight_table(gb, p->ps.sps, ref_count, slice_type_nos,
203                                   &pwt, logctx);
204
205     if (get_bits1(gb)) { // adaptive_ref_pic_marking_mode_flag
206         int i;
207         for (i = 0; i < MAX_MMCO_COUNT; i++) {
208             MMCOOpcode opcode = get_ue_golomb_31(gb);
209             if (opcode > (unsigned) MMCO_LONG) {
210                 av_log(logctx, AV_LOG_ERROR,
211                        "illegal memory management control operation %d\n",
212                        opcode);
213                 return AVERROR_INVALIDDATA;
214             }
215             if (opcode == MMCO_END)
216                return 0;
217             else if (opcode == MMCO_RESET)
218                 return 1;
219
220             if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG)
221                 get_ue_golomb_long(gb); // difference_of_pic_nums_minus1
222             if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
223                 opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG)
224                 get_ue_golomb_31(gb);
225         }
226     }
227
228     return 0;
229 }
230
231 /**
232  * Parse NAL units of found picture and decode some basic information.
233  *
234  * @param s parser context.
235  * @param avctx codec context.
236  * @param buf buffer with field/frame data.
237  * @param buf_size size of the buffer.
238  */
239 static inline int parse_nal_units(AVCodecParserContext *s,
240                                   AVCodecContext *avctx,
241                                   const uint8_t * const buf, int buf_size)
242 {
243     H264ParseContext *p = s->priv_data;
244     H2645NAL nal = { NULL };
245     int buf_index, next_avc;
246     unsigned int pps_id;
247     unsigned int slice_type;
248     int state = -1, got_reset = 0;
249     int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
250     int field_poc[2];
251     int ret;
252
253     /* set some sane default values */
254     s->pict_type         = AV_PICTURE_TYPE_I;
255     s->key_frame         = 0;
256     s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
257
258     ff_h264_sei_uninit(&p->sei);
259     p->sei.frame_packing.frame_packing_arrangement_cancel_flag = -1;
260
261     if (!buf_size)
262         return 0;
263
264     buf_index     = 0;
265     next_avc      = p->is_avc ? 0 : buf_size;
266     for (;;) {
267         const SPS *sps;
268         int src_length, consumed, nalsize = 0;
269
270         if (buf_index >= next_avc) {
271             nalsize = get_nalsize(p->nal_length_size, buf, buf_size, &buf_index, avctx);
272             if (nalsize < 0)
273                 break;
274             next_avc = buf_index + nalsize;
275         } else {
276             buf_index = find_start_code(buf, buf_size, buf_index, next_avc);
277             if (buf_index >= buf_size)
278                 break;
279             if (buf_index >= next_avc)
280                 continue;
281         }
282         src_length = next_avc - buf_index;
283
284         state = buf[buf_index];
285         switch (state & 0x1f) {
286         case H264_NAL_SLICE:
287         case H264_NAL_IDR_SLICE:
288             // Do not walk the whole buffer just to decode slice header
289             if ((state & 0x1f) == H264_NAL_IDR_SLICE || ((state >> 5) & 0x3) == 0) {
290                 /* IDR or disposable slice
291                  * No need to decode many bytes because MMCOs shall not be present. */
292                 if (src_length > 60)
293                     src_length = 60;
294             } else {
295                 /* To decode up to MMCOs */
296                 if (src_length > 1000)
297                     src_length = 1000;
298             }
299             break;
300         }
301         consumed = ff_h2645_extract_rbsp(buf + buf_index, src_length, &nal, 1);
302         if (consumed < 0)
303             break;
304
305         buf_index += consumed;
306
307         ret = init_get_bits8(&nal.gb, nal.data, nal.size);
308         if (ret < 0)
309             goto fail;
310         get_bits1(&nal.gb);
311         nal.ref_idc = get_bits(&nal.gb, 2);
312         nal.type    = get_bits(&nal.gb, 5);
313
314         switch (nal.type) {
315         case H264_NAL_SPS:
316             ff_h264_decode_seq_parameter_set(&nal.gb, avctx, &p->ps, 0);
317             break;
318         case H264_NAL_PPS:
319             ff_h264_decode_picture_parameter_set(&nal.gb, avctx, &p->ps,
320                                                  nal.size_bits);
321             break;
322         case H264_NAL_SEI:
323             ff_h264_sei_decode(&p->sei, &nal.gb, &p->ps, avctx);
324             break;
325         case H264_NAL_IDR_SLICE:
326             s->key_frame = 1;
327
328             p->poc.prev_frame_num        = 0;
329             p->poc.prev_frame_num_offset = 0;
330             p->poc.prev_poc_msb          =
331             p->poc.prev_poc_lsb          = 0;
332         /* fall through */
333         case H264_NAL_SLICE:
334             get_ue_golomb_long(&nal.gb);  // skip first_mb_in_slice
335             slice_type   = get_ue_golomb_31(&nal.gb);
336             s->pict_type = ff_h264_golomb_to_pict_type[slice_type % 5];
337             if (p->sei.recovery_point.recovery_frame_cnt >= 0) {
338                 /* key frame, since recovery_frame_cnt is set */
339                 s->key_frame = 1;
340             }
341             pps_id = get_ue_golomb(&nal.gb);
342             if (pps_id >= MAX_PPS_COUNT) {
343                 av_log(avctx, AV_LOG_ERROR,
344                        "pps_id %u out of range\n", pps_id);
345                 goto fail;
346             }
347             if (!p->ps.pps_list[pps_id]) {
348                 av_log(avctx, AV_LOG_ERROR,
349                        "non-existing PPS %u referenced\n", pps_id);
350                 goto fail;
351             }
352
353             av_buffer_unref(&p->ps.pps_ref);
354             av_buffer_unref(&p->ps.sps_ref);
355             p->ps.pps = NULL;
356             p->ps.sps = NULL;
357             p->ps.pps_ref = av_buffer_ref(p->ps.pps_list[pps_id]);
358             if (!p->ps.pps_ref)
359                 goto fail;
360             p->ps.pps = (const PPS*)p->ps.pps_ref->data;
361
362             if (!p->ps.sps_list[p->ps.pps->sps_id]) {
363                 av_log(avctx, AV_LOG_ERROR,
364                        "non-existing SPS %u referenced\n", p->ps.pps->sps_id);
365                 goto fail;
366             }
367
368             p->ps.sps_ref = av_buffer_ref(p->ps.sps_list[p->ps.pps->sps_id]);
369             if (!p->ps.sps_ref)
370                 goto fail;
371             p->ps.sps = (const SPS*)p->ps.sps_ref->data;
372
373             sps = p->ps.sps;
374
375             // heuristic to detect non marked keyframes
376             if (p->ps.sps->ref_frame_count <= 1 && p->ps.pps->ref_count[0] <= 1 && s->pict_type == AV_PICTURE_TYPE_I)
377                 s->key_frame = 1;
378
379             p->poc.frame_num = get_bits(&nal.gb, sps->log2_max_frame_num);
380
381             s->coded_width  = 16 * sps->mb_width;
382             s->coded_height = 16 * sps->mb_height;
383             s->width        = s->coded_width  - (sps->crop_right + sps->crop_left);
384             s->height       = s->coded_height - (sps->crop_top   + sps->crop_bottom);
385             if (s->width <= 0 || s->height <= 0) {
386                 s->width  = s->coded_width;
387                 s->height = s->coded_height;
388             }
389
390             switch (sps->bit_depth_luma) {
391             case 9:
392                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P9;
393                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P9;
394                 else                                  s->format = AV_PIX_FMT_YUV420P9;
395                 break;
396             case 10:
397                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P10;
398                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P10;
399                 else                                  s->format = AV_PIX_FMT_YUV420P10;
400                 break;
401             case 8:
402                 if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P;
403                 else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P;
404                 else                                  s->format = AV_PIX_FMT_YUV420P;
405                 break;
406             default:
407                 s->format = AV_PIX_FMT_NONE;
408             }
409
410             avctx->profile = ff_h264_get_profile(sps);
411             avctx->level   = sps->level_idc;
412
413             if (sps->frame_mbs_only_flag) {
414                 p->picture_structure = PICT_FRAME;
415             } else {
416                 if (get_bits1(&nal.gb)) { // field_pic_flag
417                     p->picture_structure = PICT_TOP_FIELD + get_bits1(&nal.gb); // bottom_field_flag
418                 } else {
419                     p->picture_structure = PICT_FRAME;
420                 }
421             }
422
423             if (nal.type == H264_NAL_IDR_SLICE)
424                 get_ue_golomb_long(&nal.gb); /* idr_pic_id */
425             if (sps->poc_type == 0) {
426                 p->poc.poc_lsb = get_bits(&nal.gb, sps->log2_max_poc_lsb);
427
428                 if (p->ps.pps->pic_order_present == 1 &&
429                     p->picture_structure == PICT_FRAME)
430                     p->poc.delta_poc_bottom = get_se_golomb(&nal.gb);
431             }
432
433             if (sps->poc_type == 1 &&
434                 !sps->delta_pic_order_always_zero_flag) {
435                 p->poc.delta_poc[0] = get_se_golomb(&nal.gb);
436
437                 if (p->ps.pps->pic_order_present == 1 &&
438                     p->picture_structure == PICT_FRAME)
439                     p->poc.delta_poc[1] = get_se_golomb(&nal.gb);
440             }
441
442             /* Decode POC of this picture.
443              * The prev_ values needed for decoding POC of the next picture are not set here. */
444             field_poc[0] = field_poc[1] = INT_MAX;
445             ff_h264_init_poc(field_poc, &s->output_picture_number, sps,
446                              &p->poc, p->picture_structure, nal.ref_idc);
447
448             /* Continue parsing to check if MMCO_RESET is present.
449              * FIXME: MMCO_RESET could appear in non-first slice.
450              *        Maybe, we should parse all undisposable non-IDR slice of this
451              *        picture until encountering MMCO_RESET in a slice of it. */
452             if (nal.ref_idc && nal.type != H264_NAL_IDR_SLICE) {
453                 got_reset = scan_mmco_reset(s, &nal.gb, avctx);
454                 if (got_reset < 0)
455                     goto fail;
456             }
457
458             /* Set up the prev_ values for decoding POC of the next picture. */
459             p->poc.prev_frame_num        = got_reset ? 0 : p->poc.frame_num;
460             p->poc.prev_frame_num_offset = got_reset ? 0 : p->poc.frame_num_offset;
461             if (nal.ref_idc != 0) {
462                 if (!got_reset) {
463                     p->poc.prev_poc_msb = p->poc.poc_msb;
464                     p->poc.prev_poc_lsb = p->poc.poc_lsb;
465                 } else {
466                     p->poc.prev_poc_msb = 0;
467                     p->poc.prev_poc_lsb =
468                         p->picture_structure == PICT_BOTTOM_FIELD ? 0 : field_poc[0];
469                 }
470             }
471
472             if (sps->pic_struct_present_flag) {
473                 switch (p->sei.picture_timing.pic_struct) {
474                 case SEI_PIC_STRUCT_TOP_FIELD:
475                 case SEI_PIC_STRUCT_BOTTOM_FIELD:
476                     s->repeat_pict = 0;
477                     break;
478                 case SEI_PIC_STRUCT_FRAME:
479                 case SEI_PIC_STRUCT_TOP_BOTTOM:
480                 case SEI_PIC_STRUCT_BOTTOM_TOP:
481                     s->repeat_pict = 1;
482                     break;
483                 case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
484                 case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
485                     s->repeat_pict = 2;
486                     break;
487                 case SEI_PIC_STRUCT_FRAME_DOUBLING:
488                     s->repeat_pict = 3;
489                     break;
490                 case SEI_PIC_STRUCT_FRAME_TRIPLING:
491                     s->repeat_pict = 5;
492                     break;
493                 default:
494                     s->repeat_pict = p->picture_structure == PICT_FRAME ? 1 : 0;
495                     break;
496                 }
497             } else {
498                 s->repeat_pict = p->picture_structure == PICT_FRAME ? 1 : 0;
499             }
500
501             if (p->picture_structure == PICT_FRAME) {
502                 s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
503                 if (sps->pic_struct_present_flag) {
504                     switch (p->sei.picture_timing.pic_struct) {
505                     case SEI_PIC_STRUCT_TOP_BOTTOM:
506                     case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
507                         s->field_order = AV_FIELD_TT;
508                         break;
509                     case SEI_PIC_STRUCT_BOTTOM_TOP:
510                     case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
511                         s->field_order = AV_FIELD_BB;
512                         break;
513                     default:
514                         s->field_order = AV_FIELD_PROGRESSIVE;
515                         break;
516                     }
517                 } else {
518                     if (field_poc[0] < field_poc[1])
519                         s->field_order = AV_FIELD_TT;
520                     else if (field_poc[0] > field_poc[1])
521                         s->field_order = AV_FIELD_BB;
522                     else
523                         s->field_order = AV_FIELD_PROGRESSIVE;
524                 }
525             } else {
526                 if (p->picture_structure == PICT_TOP_FIELD)
527                     s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
528                 else
529                     s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
530                 s->field_order = AV_FIELD_UNKNOWN;
531             }
532
533             av_freep(&nal.rbsp_buffer);
534             return 0; /* no need to evaluate the rest */
535         }
536     }
537     if (q264) {
538         av_freep(&nal.rbsp_buffer);
539         return 0;
540     }
541     /* didn't find a picture! */
542     av_log(avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
543 fail:
544     av_freep(&nal.rbsp_buffer);
545     return -1;
546 }
547
548 static int h264_parse(AVCodecParserContext *s,
549                       AVCodecContext *avctx,
550                       const uint8_t **poutbuf, int *poutbuf_size,
551                       const uint8_t *buf, int buf_size)
552 {
553     H264ParseContext *p = s->priv_data;
554     ParseContext *pc = &p->pc;
555     int next;
556
557     if (!p->got_first) {
558         p->got_first = 1;
559         if (avctx->extradata_size) {
560             ff_h264_decode_extradata(avctx->extradata, avctx->extradata_size,
561                                      &p->ps, &p->is_avc, &p->nal_length_size,
562                                      avctx->err_recognition, avctx);
563         }
564     }
565
566     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
567         next = buf_size;
568     } else {
569         next = h264_find_frame_end(p, buf, buf_size, avctx);
570
571         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
572             *poutbuf      = NULL;
573             *poutbuf_size = 0;
574             return buf_size;
575         }
576
577         if (next < 0 && next != END_NOT_FOUND) {
578             av_assert1(pc->last_index + next >= 0);
579             h264_find_frame_end(p, &pc->buffer[pc->last_index + next], -next, avctx); // update state
580         }
581     }
582
583     parse_nal_units(s, avctx, buf, buf_size);
584
585     if (avctx->framerate.num)
586         avctx->time_base = av_inv_q(av_mul_q(avctx->framerate, (AVRational){avctx->ticks_per_frame, 1}));
587     if (p->sei.picture_timing.cpb_removal_delay >= 0) {
588         s->dts_sync_point    = p->sei.buffering_period.present;
589         s->dts_ref_dts_delta = p->sei.picture_timing.cpb_removal_delay;
590         s->pts_dts_delta     = p->sei.picture_timing.dpb_output_delay;
591     } else {
592         s->dts_sync_point    = INT_MIN;
593         s->dts_ref_dts_delta = INT_MIN;
594         s->pts_dts_delta     = INT_MIN;
595     }
596
597     if (s->flags & PARSER_FLAG_ONCE) {
598         s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
599     }
600
601     *poutbuf      = buf;
602     *poutbuf_size = buf_size;
603     return next;
604 }
605
606 static int h264_split(AVCodecContext *avctx,
607                       const uint8_t *buf, int buf_size)
608 {
609     uint32_t state = -1;
610     int has_sps    = 0;
611     int has_pps    = 0;
612     const uint8_t *ptr = buf, *end = buf + buf_size;
613     int nalu_type;
614
615     while (ptr < end) {
616         ptr = avpriv_find_start_code(ptr, end, &state);
617         if ((state & 0xFFFFFF00) != 0x100)
618             break;
619         nalu_type = state & 0x1F;
620         if (nalu_type == H264_NAL_SPS) {
621             has_sps = 1;
622         } else if (nalu_type == H264_NAL_PPS)
623             has_pps = 1;
624         /* else if (nalu_type == 0x01 ||
625          *     nalu_type == 0x02 ||
626          *     nalu_type == 0x05) {
627          *  }
628          */
629         else if ((nalu_type != H264_NAL_SEI || has_pps) &&
630                   nalu_type != H264_NAL_AUD && nalu_type != H264_NAL_SPS_EXT &&
631                   nalu_type != 0x0f) {
632             if (has_sps) {
633                 while (ptr - 4 > buf && ptr[-5] == 0)
634                     ptr--;
635                 return ptr - 4 - buf;
636             }
637         }
638     }
639
640     return 0;
641 }
642
643 static void h264_close(AVCodecParserContext *s)
644 {
645     H264ParseContext *p = s->priv_data;
646     ParseContext *pc = &p->pc;
647
648     av_freep(&pc->buffer);
649
650     ff_h264_sei_uninit(&p->sei);
651     ff_h264_ps_uninit(&p->ps);
652 }
653
654 static av_cold int init(AVCodecParserContext *s)
655 {
656     H264ParseContext *p = s->priv_data;
657
658     ff_h264dsp_init(&p->h264dsp, 8, 1);
659     return 0;
660 }
661
662 AVCodecParser ff_h264_parser = {
663     .codec_ids      = { AV_CODEC_ID_H264 },
664     .priv_data_size = sizeof(H264ParseContext),
665     .parser_init    = init,
666     .parser_parse   = h264_parse,
667     .parser_close   = h264_close,
668     .split          = h264_split,
669 };