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/libavcodec/h264_parser.c

http://github.com/FFmpeg/FFmpeg
C | 712 lines | 578 code | 77 blank | 57 comment | 226 complexity | ba218d4b72e90d48fb08b5d544c6c196 MD5 | raw file
  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
 50typedef 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
 68static 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
150found:
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
158static 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 */
244static 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            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            p->ps.sps = p->ps.pps->sps;
371            sps       = p->ps.sps;
372
373            // heuristic to detect non marked keyframes
374            if (p->ps.sps->ref_frame_count <= 1 && p->ps.pps->ref_count[0] <= 1 && s->pict_type == AV_PICTURE_TYPE_I)
375                s->key_frame = 1;
376
377            p->poc.frame_num = get_bits(&nal.gb, sps->log2_max_frame_num);
378
379            s->coded_width  = 16 * sps->mb_width;
380            s->coded_height = 16 * sps->mb_height;
381            s->width        = s->coded_width  - (sps->crop_right + sps->crop_left);
382            s->height       = s->coded_height - (sps->crop_top   + sps->crop_bottom);
383            if (s->width <= 0 || s->height <= 0) {
384                s->width  = s->coded_width;
385                s->height = s->coded_height;
386            }
387
388            switch (sps->bit_depth_luma) {
389            case 9:
390                if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P9;
391                else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P9;
392                else                                  s->format = AV_PIX_FMT_YUV420P9;
393                break;
394            case 10:
395                if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P10;
396                else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P10;
397                else                                  s->format = AV_PIX_FMT_YUV420P10;
398                break;
399            case 8:
400                if (sps->chroma_format_idc == 3)      s->format = AV_PIX_FMT_YUV444P;
401                else if (sps->chroma_format_idc == 2) s->format = AV_PIX_FMT_YUV422P;
402                else                                  s->format = AV_PIX_FMT_YUV420P;
403                break;
404            default:
405                s->format = AV_PIX_FMT_NONE;
406            }
407
408            avctx->profile = ff_h264_get_profile(sps);
409            avctx->level   = sps->level_idc;
410
411            if (sps->frame_mbs_only_flag) {
412                p->picture_structure = PICT_FRAME;
413            } else {
414                if (get_bits1(&nal.gb)) { // field_pic_flag
415                    p->picture_structure = PICT_TOP_FIELD + get_bits1(&nal.gb); // bottom_field_flag
416                } else {
417                    p->picture_structure = PICT_FRAME;
418                }
419            }
420
421            if (nal.type == H264_NAL_IDR_SLICE)
422                get_ue_golomb_long(&nal.gb); /* idr_pic_id */
423            if (sps->poc_type == 0) {
424                p->poc.poc_lsb = get_bits(&nal.gb, sps->log2_max_poc_lsb);
425
426                if (p->ps.pps->pic_order_present == 1 &&
427                    p->picture_structure == PICT_FRAME)
428                    p->poc.delta_poc_bottom = get_se_golomb(&nal.gb);
429            }
430
431            if (sps->poc_type == 1 &&
432                !sps->delta_pic_order_always_zero_flag) {
433                p->poc.delta_poc[0] = get_se_golomb(&nal.gb);
434
435                if (p->ps.pps->pic_order_present == 1 &&
436                    p->picture_structure == PICT_FRAME)
437                    p->poc.delta_poc[1] = get_se_golomb(&nal.gb);
438            }
439
440            /* Decode POC of this picture.
441             * The prev_ values needed for decoding POC of the next picture are not set here. */
442            field_poc[0] = field_poc[1] = INT_MAX;
443            ret = ff_h264_init_poc(field_poc, &s->output_picture_number, sps,
444                             &p->poc, p->picture_structure, nal.ref_idc);
445            if (ret < 0)
446                goto fail;
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 (p->sei.picture_timing.present) {
473                ret = ff_h264_sei_process_picture_timing(&p->sei.picture_timing,
474                                                         sps, avctx);
475                if (ret < 0) {
476                    av_log(avctx, AV_LOG_ERROR, "Error processing the picture timing SEI\n");
477                    p->sei.picture_timing.present = 0;
478                }
479            }
480
481            if (sps->pic_struct_present_flag && p->sei.picture_timing.present) {
482                switch (p->sei.picture_timing.pic_struct) {
483                case H264_SEI_PIC_STRUCT_TOP_FIELD:
484                case H264_SEI_PIC_STRUCT_BOTTOM_FIELD:
485                    s->repeat_pict = 0;
486                    break;
487                case H264_SEI_PIC_STRUCT_FRAME:
488                case H264_SEI_PIC_STRUCT_TOP_BOTTOM:
489                case H264_SEI_PIC_STRUCT_BOTTOM_TOP:
490                    s->repeat_pict = 1;
491                    break;
492                case H264_SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
493                case H264_SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
494                    s->repeat_pict = 2;
495                    break;
496                case H264_SEI_PIC_STRUCT_FRAME_DOUBLING:
497                    s->repeat_pict = 3;
498                    break;
499                case H264_SEI_PIC_STRUCT_FRAME_TRIPLING:
500                    s->repeat_pict = 5;
501                    break;
502                default:
503                    s->repeat_pict = p->picture_structure == PICT_FRAME ? 1 : 0;
504                    break;
505                }
506            } else {
507                s->repeat_pict = p->picture_structure == PICT_FRAME ? 1 : 0;
508            }
509
510            if (p->picture_structure == PICT_FRAME) {
511                s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
512                if (sps->pic_struct_present_flag && p->sei.picture_timing.present) {
513                    switch (p->sei.picture_timing.pic_struct) {
514                    case H264_SEI_PIC_STRUCT_TOP_BOTTOM:
515                    case H264_SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
516                        s->field_order = AV_FIELD_TT;
517                        break;
518                    case H264_SEI_PIC_STRUCT_BOTTOM_TOP:
519                    case H264_SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
520                        s->field_order = AV_FIELD_BB;
521                        break;
522                    default:
523                        s->field_order = AV_FIELD_PROGRESSIVE;
524                        break;
525                    }
526                } else {
527                    if (field_poc[0] < field_poc[1])
528                        s->field_order = AV_FIELD_TT;
529                    else if (field_poc[0] > field_poc[1])
530                        s->field_order = AV_FIELD_BB;
531                    else
532                        s->field_order = AV_FIELD_PROGRESSIVE;
533                }
534            } else {
535                if (p->picture_structure == PICT_TOP_FIELD)
536                    s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
537                else
538                    s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
539                if (p->poc.frame_num == p->last_frame_num &&
540                    p->last_picture_structure != AV_PICTURE_STRUCTURE_UNKNOWN &&
541                    p->last_picture_structure != AV_PICTURE_STRUCTURE_FRAME &&
542                    p->last_picture_structure != s->picture_structure) {
543                    if (p->last_picture_structure == AV_PICTURE_STRUCTURE_TOP_FIELD)
544                        s->field_order = AV_FIELD_TT;
545                    else
546                        s->field_order = AV_FIELD_BB;
547                } else {
548                    s->field_order = AV_FIELD_UNKNOWN;
549                }
550                p->last_picture_structure = s->picture_structure;
551                p->last_frame_num = p->poc.frame_num;
552            }
553
554            av_freep(&rbsp.rbsp_buffer);
555            return 0; /* no need to evaluate the rest */
556        }
557    }
558    if (q264) {
559        av_freep(&rbsp.rbsp_buffer);
560        return 0;
561    }
562    /* didn't find a picture! */
563    av_log(avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
564fail:
565    av_freep(&rbsp.rbsp_buffer);
566    return -1;
567}
568
569static 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
647static 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
684static 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
695static 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
705AVCodecParser 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};