git.sesse.net Git - ffmpeg/blob - 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 Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 / MPEG4 part10 parser.
  25  * @author Michael Niedermayer <michaelni@gmx.at>
  26  */
  27
  28 #include "libavutil/attributes.h"
  29 #include "parser.h"
  30 #include "h264data.h"
  31 #include "golomb.h"
  32 #include "internal.h"
  33 #include "mpegutils.h"
  34
  35 #include <assert.h>
  36
  37 typedef struct H264ParseContext {
  38     H264Context h;
  39     ParseContext pc;
  40     int got_first;
  41 } H264ParseContext;
  42
  43
  44 static int h264_find_frame_end(H264ParseContext *p, const uint8_t *buf,
  45                                int buf_size)
  46 {
  47     H264Context *h = &p->h;
  48     int i;
  49     uint32_t state;
  50     ParseContext *pc = &p->pc;
  51 //    mb_addr= pc->mb_addr - 1;
  52     state = pc->state;
  53     if (state > 13)
  54         state = 7;
  55
  56     for (i = 0; i < buf_size; i++) {
  57         if (state == 7) {
  58             i += h->h264dsp.startcode_find_candidate(buf + i, buf_size - i);
  59             if (i < buf_size)
  60                 state = 2;
  61         } else if (state <= 2) {
  62             if (buf[i] == 1)
  63                 state ^= 5;            // 2->7, 1->4, 0->5
  64             else if (buf[i])
  65                 state = 7;
  66             else
  67                 state >>= 1;           // 2->1, 1->0, 0->0
  68         } else if (state <= 5) {
  69             int nalu_type = buf[i] & 0x1F;
  70             if (nalu_type == NAL_SEI || nalu_type == NAL_SPS ||
  71                 nalu_type == NAL_PPS || nalu_type == NAL_AUD) {
  72                 if (pc->frame_start_found) {
  73                     i++;
  74                     goto found;
  75                 }
  76             } else if (nalu_type == NAL_SLICE || nalu_type == NAL_DPA ||
  77                        nalu_type == NAL_IDR_SLICE) {
  78                 if (pc->frame_start_found) {
  79                     state += 8;
  80                     continue;
  81                 } else
  82                     pc->frame_start_found = 1;
  83             }
  84             state = 7;
  85         } else {
  86             // first_mb_in_slice is 0, probably the first nal of a new slice
  87             if (buf[i] & 0x80)
  88                 goto found;
  89             state = 7;
  90         }
  91     }
  92     pc->state = state;
  93     return END_NOT_FOUND;
  94
  95 found:
  96     pc->state             = 7;
  97     pc->frame_start_found = 0;
  98     return i - (state & 5);
  99 }
 100
 101 static int scan_mmco_reset(AVCodecParserContext *s)
 102 {
 103     H264ParseContext *p = s->priv_data;
 104     H264Context      *h = &p->h;
 105     H264SliceContext *sl = &h->slice_ctx[0];
 106
 107     sl->slice_type_nos = s->pict_type & 3;
 108
 109     if (h->pps.redundant_pic_cnt_present)
 110         get_ue_golomb(&h->gb); // redundant_pic_count
 111
 112     if (ff_set_ref_count(h, sl) < 0)
 113         return AVERROR_INVALIDDATA;
 114
 115     if (sl->slice_type_nos != AV_PICTURE_TYPE_I) {
 116         int list;
 117         for (list = 0; list < h->list_count; list++) {
 118             if (get_bits1(&h->gb)) {
 119                 int index;
 120                 for (index = 0; ; index++) {
 121                     unsigned int reordering_of_pic_nums_idc = get_ue_golomb_31(&h->gb);
 122
 123                     if (reordering_of_pic_nums_idc < 3)
 124                         get_ue_golomb(&h->gb);
 125                     else if (reordering_of_pic_nums_idc > 3) {
 126                         av_log(h->avctx, AV_LOG_ERROR,
 127                                "illegal reordering_of_pic_nums_idc %d\n",
 128                                reordering_of_pic_nums_idc);
 129                         return AVERROR_INVALIDDATA;
 130                     } else
 131                         break;
 132
 133                     if (index >= h->ref_count[list]) {
 134                         av_log(h->avctx, AV_LOG_ERROR,
 135                                "reference count %d overflow\n", index);
 136                         return AVERROR_INVALIDDATA;
 137                     }
 138                 }
 139             }
 140         }
 141     }
 142
 143     if ((h->pps.weighted_pred && sl->slice_type_nos == AV_PICTURE_TYPE_P) ||
 144         (h->pps.weighted_bipred_idc == 1 && sl->slice_type_nos == AV_PICTURE_TYPE_B))
 145         ff_pred_weight_table(h, sl);
 146
 147     if (get_bits1(&h->gb)) { // adaptive_ref_pic_marking_mode_flag
 148         int i;
 149         for (i = 0; i < MAX_MMCO_COUNT; i++) {
 150             MMCOOpcode opcode = get_ue_golomb_31(&h->gb);
 151             if (opcode > (unsigned) MMCO_LONG) {
 152                 av_log(h->avctx, AV_LOG_ERROR,
 153                        "illegal memory management control operation %d\n",
 154                        opcode);
 155                 return AVERROR_INVALIDDATA;
 156             }
 157             if (opcode == MMCO_END)
 158                return 0;
 159             else if (opcode == MMCO_RESET)
 160                 return 1;
 161
 162             if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG)
 163                 get_ue_golomb(&h->gb);
 164             if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
 165                 opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG)
 166                 get_ue_golomb_31(&h->gb);
 167         }
 168     }
 169
 170     return 0;
 171 }
 172
 173 /**
 174  * Parse NAL units of found picture and decode some basic information.
 175  *
 176  * @param s parser context.
 177  * @param avctx codec context.
 178  * @param buf buffer with field/frame data.
 179  * @param buf_size size of the buffer.
 180  */
 181 static inline int parse_nal_units(AVCodecParserContext *s,
 182                                   AVCodecContext *avctx,
 183                                   const uint8_t *buf, int buf_size)
 184 {
 185     H264ParseContext *p = s->priv_data;
 186     H264Context      *h = &p->h;
 187     const uint8_t *buf_end = buf + buf_size;
 188     unsigned int pps_id;
 189     unsigned int slice_type;
 190     int state = -1, got_reset = 0;
 191     const uint8_t *ptr;
 192     int field_poc[2];
 193
 194     /* set some sane default values */
 195     s->pict_type         = AV_PICTURE_TYPE_I;
 196     s->key_frame         = 0;
 197     s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
 198
 199     h->avctx = avctx;
 200     ff_h264_reset_sei(h);
 201
 202     if (!buf_size)
 203         return 0;
 204
 205     for (;;) {
 206         int src_length, dst_length, consumed;
 207         buf = avpriv_find_start_code(buf, buf_end, &state);
 208         if (buf >= buf_end)
 209             break;
 210         --buf;
 211         src_length = buf_end - buf;
 212         switch (state & 0x1f) {
 213         case NAL_SLICE:
 214         case NAL_IDR_SLICE:
 215             // Do not walk the whole buffer just to decode slice header
 216             if ((state & 0x1f) == NAL_IDR_SLICE || ((state >> 5) & 0x3) == 0) {
 217                 /* IDR or disposable slice
 218                  * No need to decode many bytes because MMCOs shall not be present. */
 219                 if (src_length > 60)
 220                     src_length = 60;
 221             } else {
 222                 /* To decode up to MMCOs */
 223                 if (src_length > 1000)
 224                     src_length = 1000;
 225             }
 226             break;
 227         }
 228         ptr = ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
 229         if (!ptr || dst_length < 0)
 230             break;
 231
 232         init_get_bits(&h->gb, ptr, 8 * dst_length);
 233         switch (h->nal_unit_type) {
 234         case NAL_SPS:
 235             ff_h264_decode_seq_parameter_set(h);
 236             break;
 237         case NAL_PPS:
 238             ff_h264_decode_picture_parameter_set(h, h->gb.size_in_bits);
 239             break;
 240         case NAL_SEI:
 241             ff_h264_decode_sei(h);
 242             break;
 243         case NAL_IDR_SLICE:
 244             s->key_frame = 1;
 245
 246             h->prev_frame_num        = 0;
 247             h->prev_frame_num_offset = 0;
 248             h->prev_poc_msb          =
 249             h->prev_poc_lsb          = 0;
 250         /* fall through */
 251         case NAL_SLICE:
 252             get_ue_golomb(&h->gb);  // skip first_mb_in_slice
 253             slice_type   = get_ue_golomb_31(&h->gb);
 254             s->pict_type = golomb_to_pict_type[slice_type % 5];
 255             if (h->sei_recovery_frame_cnt >= 0) {
 256                 /* key frame, since recovery_frame_cnt is set */
 257                 s->key_frame = 1;
 258             }
 259             pps_id = get_ue_golomb(&h->gb);
 260             if (pps_id >= MAX_PPS_COUNT) {
 261                 av_log(h->avctx, AV_LOG_ERROR,
 262                        "pps_id %u out of range\n", pps_id);
 263                 return -1;
 264             }
 265             if (!h->pps_buffers[pps_id]) {
 266                 av_log(h->avctx, AV_LOG_ERROR,
 267                        "non-existing PPS %u referenced\n", pps_id);
 268                 return -1;
 269             }
 270             h->pps = *h->pps_buffers[pps_id];
 271             if (!h->sps_buffers[h->pps.sps_id]) {
 272                 av_log(h->avctx, AV_LOG_ERROR,
 273                        "non-existing SPS %u referenced\n", h->pps.sps_id);
 274                 return -1;
 275             }
 276             h->sps       = *h->sps_buffers[h->pps.sps_id];
 277             h->frame_num = get_bits(&h->gb, h->sps.log2_max_frame_num);
 278
 279             s->coded_width  = 16 * h->sps.mb_width;
 280             s->coded_height = 16 * h->sps.mb_height;
 281             s->width        = s->coded_width  - (h->sps.crop_right + h->sps.crop_left);
 282             s->height       = s->coded_height - (h->sps.crop_top   + h->sps.crop_bottom);
 283             if (s->width <= 0 || s->height <= 0) {
 284                 s->width  = s->coded_width;
 285                 s->height = s->coded_height;
 286             }
 287
 288             switch (h->sps.bit_depth_luma) {
 289             case 9:
 290                 if (CHROMA444(h))      s->format = AV_PIX_FMT_YUV444P9;
 291                 else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P9;
 292                 else                   s->format = AV_PIX_FMT_YUV420P9;
 293                 break;
 294             case 10:
 295                 if (CHROMA444(h))      s->format = AV_PIX_FMT_YUV444P10;
 296                 else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P10;
 297                 else                   s->format = AV_PIX_FMT_YUV420P10;
 298                 break;
 299             case 8:
 300                 if (CHROMA444(h))      s->format = AV_PIX_FMT_YUV444P;
 301                 else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P;
 302                 else                   s->format = AV_PIX_FMT_YUV420P;
 303                 break;
 304             default:
 305                 s->format = AV_PIX_FMT_NONE;
 306             }
 307
 308             avctx->profile = ff_h264_get_profile(&h->sps);
 309             avctx->level   = h->sps.level_idc;
 310
 311             if (h->sps.frame_mbs_only_flag) {
 312                 h->picture_structure = PICT_FRAME;
 313             } else {
 314                 if (get_bits1(&h->gb)) { // field_pic_flag
 315                     h->picture_structure = PICT_TOP_FIELD + get_bits1(&h->gb); // bottom_field_flag
 316                 } else {
 317                     h->picture_structure = PICT_FRAME;
 318                 }
 319             }
 320
 321             if (h->nal_unit_type == NAL_IDR_SLICE)
 322                 get_ue_golomb(&h->gb); /* idr_pic_id */
 323             if (h->sps.poc_type == 0) {
 324                 h->poc_lsb = get_bits(&h->gb, h->sps.log2_max_poc_lsb);
 325
 326                 if (h->pps.pic_order_present == 1 &&
 327                     h->picture_structure == PICT_FRAME)
 328                     h->delta_poc_bottom = get_se_golomb(&h->gb);
 329             }
 330
 331             if (h->sps.poc_type == 1 &&
 332                 !h->sps.delta_pic_order_always_zero_flag) {
 333                 h->delta_poc[0] = get_se_golomb(&h->gb);
 334
 335                 if (h->pps.pic_order_present == 1 &&
 336                     h->picture_structure == PICT_FRAME)
 337                     h->delta_poc[1] = get_se_golomb(&h->gb);
 338             }
 339
 340             /* Decode POC of this picture.
 341              * The prev_ values needed for decoding POC of the next picture are not set here. */
 342             field_poc[0] = field_poc[1] = INT_MAX;
 343             ff_init_poc(h, field_poc, &s->output_picture_number);
 344
 345             /* Continue parsing to check if MMCO_RESET is present.
 346              * FIXME: MMCO_RESET could appear in non-first slice.
 347              *        Maybe, we should parse all undisposable non-IDR slice of this
 348              *        picture until encountering MMCO_RESET in a slice of it. */
 349             if (h->nal_ref_idc && h->nal_unit_type != NAL_IDR_SLICE) {
 350                 got_reset = scan_mmco_reset(s);
 351                 if (got_reset < 0)
 352                     return got_reset;
 353             }
 354
 355             /* Set up the prev_ values for decoding POC of the next picture. */
 356             h->prev_frame_num        = got_reset ? 0 : h->frame_num;
 357             h->prev_frame_num_offset = got_reset ? 0 : h->frame_num_offset;
 358             if (h->nal_ref_idc != 0) {
 359                 if (!got_reset) {
 360                     h->prev_poc_msb = h->poc_msb;
 361                     h->prev_poc_lsb = h->poc_lsb;
 362                 } else {
 363                     h->prev_poc_msb = 0;
 364                     h->prev_poc_lsb =
 365                         h->picture_structure == PICT_BOTTOM_FIELD ? 0 : field_poc[0];
 366                 }
 367             }
 368
 369             if (h->sps.pic_struct_present_flag) {
 370                 switch (h->sei_pic_struct) {
 371                 case SEI_PIC_STRUCT_TOP_FIELD:
 372                 case SEI_PIC_STRUCT_BOTTOM_FIELD:
 373                     s->repeat_pict = 0;
 374                     break;
 375                 case SEI_PIC_STRUCT_FRAME:
 376                 case SEI_PIC_STRUCT_TOP_BOTTOM:
 377                 case SEI_PIC_STRUCT_BOTTOM_TOP:
 378                     s->repeat_pict = 1;
 379                     break;
 380                 case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
 381                 case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
 382                     s->repeat_pict = 2;
 383                     break;
 384                 case SEI_PIC_STRUCT_FRAME_DOUBLING:
 385                     s->repeat_pict = 3;
 386                     break;
 387                 case SEI_PIC_STRUCT_FRAME_TRIPLING:
 388                     s->repeat_pict = 5;
 389                     break;
 390                 default:
 391                     s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
 392                     break;
 393                 }
 394             } else {
 395                 s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
 396             }
 397
 398             if (h->picture_structure == PICT_FRAME) {
 399                 s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
 400                 if (h->sps.pic_struct_present_flag) {
 401                     switch (h->sei_pic_struct) {
 402                     case SEI_PIC_STRUCT_TOP_BOTTOM:
 403                     case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
 404                         s->field_order = AV_FIELD_TT;
 405                         break;
 406                     case SEI_PIC_STRUCT_BOTTOM_TOP:
 407                     case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
 408                         s->field_order = AV_FIELD_BB;
 409                         break;
 410                     default:
 411                         s->field_order = AV_FIELD_PROGRESSIVE;
 412                         break;
 413                     }
 414                 } else {
 415                     if (field_poc[0] < field_poc[1])
 416                         s->field_order = AV_FIELD_TT;
 417                     else if (field_poc[0] > field_poc[1])
 418                         s->field_order = AV_FIELD_BB;
 419                     else
 420                         s->field_order = AV_FIELD_PROGRESSIVE;
 421                 }
 422             } else {
 423                 if (h->picture_structure == PICT_TOP_FIELD)
 424                     s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
 425                 else
 426                     s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
 427                 s->field_order = AV_FIELD_UNKNOWN;
 428             }
 429
 430             return 0; /* no need to evaluate the rest */
 431         }
 432         buf += consumed;
 433     }
 434     /* didn't find a picture! */
 435     av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit\n");
 436     return -1;
 437 }
 438
 439 static int h264_parse(AVCodecParserContext *s,
 440                       AVCodecContext *avctx,
 441                       const uint8_t **poutbuf, int *poutbuf_size,
 442                       const uint8_t *buf, int buf_size)
 443 {
 444     H264ParseContext *p = s->priv_data;
 445     H264Context      *h = &p->h;
 446     ParseContext *pc = &p->pc;
 447     int next;
 448
 449     if (!p->got_first) {
 450         p->got_first = 1;
 451         if (avctx->extradata_size) {
 452             h->avctx = avctx;
 453             // must be done like in the decoder.
 454             // otherwise opening the parser, creating extradata,
 455             // and then closing and opening again
 456             // will cause has_b_frames to be always set.
 457             // NB: estimate_timings_from_pts behaves exactly like this.
 458             if (!avctx->has_b_frames)
 459                 h->low_delay = 1;
 460             ff_h264_decode_extradata(h);
 461         }
 462     }
 463
 464     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
 465         next = buf_size;
 466     } else {
 467         next = h264_find_frame_end(p, buf, buf_size);
 468
 469         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
 470             *poutbuf      = NULL;
 471             *poutbuf_size = 0;
 472             return buf_size;
 473         }
 474
 475         if (next < 0 && next != END_NOT_FOUND) {
 476             assert(pc->last_index + next >= 0);
 477             h264_find_frame_end(p, &pc->buffer[pc->last_index + next], -next); // update state
 478         }
 479     }
 480
 481     parse_nal_units(s, avctx, buf, buf_size);
 482
 483     if (h->sei_cpb_removal_delay >= 0) {
 484         s->dts_sync_point    = h->sei_buffering_period_present;
 485         s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
 486         s->pts_dts_delta     = h->sei_dpb_output_delay;
 487     } else {
 488         s->dts_sync_point    = INT_MIN;
 489         s->dts_ref_dts_delta = INT_MIN;
 490         s->pts_dts_delta     = INT_MIN;
 491     }
 492
 493     if (s->flags & PARSER_FLAG_ONCE) {
 494         s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
 495     }
 496
 497     *poutbuf      = buf;
 498     *poutbuf_size = buf_size;
 499     return next;
 500 }
 501
 502 static int h264_split(AVCodecContext *avctx,
 503                       const uint8_t *buf, int buf_size)
 504 {
 505     int i;
 506     uint32_t state = -1;
 507     int has_sps    = 0;
 508
 509     for (i = 0; i <= buf_size; i++) {
 510         if ((state & 0xFFFFFF1F) == 0x107)
 511             has_sps = 1;
 512         /*  if((state&0xFFFFFF1F) == 0x101 ||
 513          *     (state&0xFFFFFF1F) == 0x102 ||
 514          *     (state&0xFFFFFF1F) == 0x105) {
 515          *  }
 516          */
 517         if ((state & 0xFFFFFF00) == 0x100 && (state & 0xFFFFFF1F) != 0x106 &&
 518             (state & 0xFFFFFF1F) != 0x107 && (state & 0xFFFFFF1F) != 0x108 &&
 519             (state & 0xFFFFFF1F) != 0x109 && (state & 0xFFFFFF1F) != 0x10d &&
 520             (state & 0xFFFFFF1F) != 0x10f) {
 521             if (has_sps) {
 522                 while (i > 4 && buf[i - 5] == 0)
 523                     i--;
 524                 return i - 4;
 525             }
 526         }
 527         if (i < buf_size)
 528             state = (state << 8) | buf[i];
 529     }
 530     return 0;
 531 }
 532
 533 static void close(AVCodecParserContext *s)
 534 {
 535     H264ParseContext *p = s->priv_data;
 536     H264Context      *h = &p->h;
 537     ParseContext *pc = &p->pc;
 538
 539     av_free(pc->buffer);
 540     ff_h264_free_context(h);
 541 }
 542
 543 static av_cold int init(AVCodecParserContext *s)
 544 {
 545     H264ParseContext *p = s->priv_data;
 546     H264Context      *h = &p->h;
 547
 548     h->slice_ctx = av_mallocz(sizeof(*h->slice_ctx));
 549     if (!h->slice_ctx)
 550         return 0;
 551     h->nb_slice_ctx = 1;
 552
 553     h->thread_context[0]   = h;
 554     h->slice_context_count = 1;
 555     ff_h264dsp_init(&h->h264dsp, 8, 1);
 556     return 0;
 557 }
 558
 559 AVCodecParser ff_h264_parser = {
 560     .codec_ids      = { AV_CODEC_ID_H264 },
 561     .priv_data_size = sizeof(H264ParseContext),
 562     .parser_init    = init,
 563     .parser_parse   = h264_parse,
 564     .parser_close   = close,
 565     .split          = h264_split,
 566 };