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 <assert.h>
  29 #include <stdint.h>
  30
  31 #include "libavutil/avutil.h"
  32 #include "libavutil/error.h"
  33 #include "libavutil/log.h"
  34 #include "libavutil/mem.h"
  35 #include "libavutil/pixfmt.h"
  36
  37 #include "get_bits.h"
  38 #include "golomb.h"
  39 #include "h264.h"
  40 #include "h264data.h"
  41 #include "internal.h"
  42 #include "mpegutils.h"
  43 #include "parser.h"
  44
  45 typedef struct H264ParseContext {
  46     H264Context h;
  47     ParseContext pc;
  48     int got_first;
  49 } H264ParseContext;
  50
  51
  52 static int h264_find_frame_end(H264ParseContext *p, const uint8_t *buf,
  53                                int buf_size)
  54 {
  55     H264Context *h = &p->h;
  56     int i;
  57     uint32_t state;
  58     ParseContext *pc = &p->pc;
  59 //    mb_addr= pc->mb_addr - 1;
  60     state = pc->state;
  61     if (state > 13)
  62         state = 7;
  63
  64     for (i = 0; i < buf_size; i++) {
  65         if (state == 7) {
  66             i += h->h264dsp.startcode_find_candidate(buf + i, buf_size - i);
  67             if (i < buf_size)
  68                 state = 2;
  69         } else if (state <= 2) {
  70             if (buf[i] == 1)
  71                 state ^= 5;            // 2->7, 1->4, 0->5
  72             else if (buf[i])
  73                 state = 7;
  74             else
  75                 state >>= 1;           // 2->1, 1->0, 0->0
  76         } else if (state <= 5) {
  77             int nalu_type = buf[i] & 0x1F;
  78             if (nalu_type == NAL_SEI || nalu_type == NAL_SPS ||
  79                 nalu_type == NAL_PPS || nalu_type == NAL_AUD) {
  80                 if (pc->frame_start_found) {
  81                     i++;
  82                     goto found;
  83                 }
  84             } else if (nalu_type == NAL_SLICE || nalu_type == NAL_DPA ||
  85                        nalu_type == NAL_IDR_SLICE) {
  86                 if (pc->frame_start_found) {
  87                     state += 8;
  88                     continue;
  89                 } else
  90                     pc->frame_start_found = 1;
  91             }
  92             state = 7;
  93         } else {
  94             // first_mb_in_slice is 0, probably the first nal of a new slice
  95             if (buf[i] & 0x80)
  96                 goto found;
  97             state = 7;
  98         }
  99     }
 100     pc->state = state;
 101     return END_NOT_FOUND;
 102
 103 found:
 104     pc->state             = 7;
 105     pc->frame_start_found = 0;
 106     return i - (state & 5);
 107 }
 108
 109 static int scan_mmco_reset(AVCodecParserContext *s)
 110 {
 111     H264ParseContext *p = s->priv_data;
 112     H264Context      *h = &p->h;
 113     H264SliceContext *sl = &h->slice_ctx[0];
 114
 115     sl->slice_type_nos = s->pict_type & 3;
 116
 117     if (h->pps.redundant_pic_cnt_present)
 118         get_ue_golomb(&sl->gb); // redundant_pic_count
 119
 120     if (ff_set_ref_count(h, sl) < 0)
 121         return AVERROR_INVALIDDATA;
 122
 123     if (sl->slice_type_nos != AV_PICTURE_TYPE_I) {
 124         int list;
 125         for (list = 0; list < sl->list_count; list++) {
 126             if (get_bits1(&sl->gb)) {
 127                 int index;
 128                 for (index = 0; ; index++) {
 129                     unsigned int reordering_of_pic_nums_idc = get_ue_golomb_31(&sl->gb);
 130
 131                     if (reordering_of_pic_nums_idc < 3)
 132                         get_ue_golomb(&sl->gb);
 133                     else if (reordering_of_pic_nums_idc > 3) {
 134                         av_log(h->avctx, AV_LOG_ERROR,
 135                                "illegal reordering_of_pic_nums_idc %d\n",
 136                                reordering_of_pic_nums_idc);
 137                         return AVERROR_INVALIDDATA;
 138                     } else
 139                         break;
 140
 141                     if (index >= sl->ref_count[list]) {
 142                         av_log(h->avctx, AV_LOG_ERROR,
 143                                "reference count %d overflow\n", index);
 144                         return AVERROR_INVALIDDATA;
 145                     }
 146                 }
 147             }
 148         }
 149     }
 150
 151     if ((h->pps.weighted_pred && sl->slice_type_nos == AV_PICTURE_TYPE_P) ||
 152         (h->pps.weighted_bipred_idc == 1 && sl->slice_type_nos == AV_PICTURE_TYPE_B))
 153         ff_pred_weight_table(h, sl);
 154
 155     if (get_bits1(&sl->gb)) { // adaptive_ref_pic_marking_mode_flag
 156         int i;
 157         for (i = 0; i < MAX_MMCO_COUNT; i++) {
 158             MMCOOpcode opcode = get_ue_golomb_31(&sl->gb);
 159             if (opcode > (unsigned) MMCO_LONG) {
 160                 av_log(h->avctx, AV_LOG_ERROR,
 161                        "illegal memory management control operation %d\n",
 162                        opcode);
 163                 return AVERROR_INVALIDDATA;
 164             }
 165             if (opcode == MMCO_END)
 166                return 0;
 167             else if (opcode == MMCO_RESET)
 168                 return 1;
 169
 170             if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG)
 171                 get_ue_golomb(&sl->gb);
 172             if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
 173                 opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG)
 174                 get_ue_golomb_31(&sl->gb);
 175         }
 176     }
 177
 178     return 0;
 179 }
 180
 181 /**
 182  * Parse NAL units of found picture and decode some basic information.
 183  *
 184  * @param s parser context.
 185  * @param avctx codec context.
 186  * @param buf buffer with field/frame data.
 187  * @param buf_size size of the buffer.
 188  */
 189 static inline int parse_nal_units(AVCodecParserContext *s,
 190                                   AVCodecContext *avctx,
 191                                   const uint8_t *buf, int buf_size)
 192 {
 193     H264ParseContext *p = s->priv_data;
 194     H264Context      *h = &p->h;
 195     H264SliceContext *sl = &h->slice_ctx[0];
 196     const uint8_t *buf_end = buf + buf_size;
 197     unsigned int pps_id;
 198     unsigned int slice_type;
 199     int state = -1, got_reset = 0;
 200     const uint8_t *ptr;
 201     int field_poc[2];
 202
 203     /* set some sane default values */
 204     s->pict_type         = AV_PICTURE_TYPE_I;
 205     s->key_frame         = 0;
 206     s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
 207
 208     h->avctx = avctx;
 209     ff_h264_reset_sei(h);
 210
 211     if (!buf_size)
 212         return 0;
 213
 214     for (;;) {
 215         int src_length, dst_length, consumed;
 216         buf = avpriv_find_start_code(buf, buf_end, &state);
 217         if (buf >= buf_end)
 218             break;
 219         --buf;
 220         src_length = buf_end - buf;
 221         switch (state & 0x1f) {
 222         case NAL_SLICE:
 223         case NAL_IDR_SLICE:
 224             // Do not walk the whole buffer just to decode slice header
 225             if ((state & 0x1f) == NAL_IDR_SLICE || ((state >> 5) & 0x3) == 0) {
 226                 /* IDR or disposable slice
 227                  * No need to decode many bytes because MMCOs shall not be present. */
 228                 if (src_length > 60)
 229                     src_length = 60;
 230             } else {
 231                 /* To decode up to MMCOs */
 232                 if (src_length > 1000)
 233                     src_length = 1000;
 234             }
 235             break;
 236         }
 237         ptr = ff_h264_decode_nal(h, sl, buf, &dst_length, &consumed, src_length);
 238         if (!ptr || dst_length < 0)
 239             break;
 240
 241         init_get_bits(&h->gb, ptr, 8 * dst_length);
 242         switch (h->nal_unit_type) {
 243         case NAL_SPS:
 244             ff_h264_decode_seq_parameter_set(h);
 245             break;
 246         case NAL_PPS:
 247             ff_h264_decode_picture_parameter_set(h, h->gb.size_in_bits);
 248             break;
 249         case NAL_SEI:
 250             ff_h264_decode_sei(h);
 251             break;
 252         case NAL_IDR_SLICE:
 253             s->key_frame = 1;
 254
 255             h->prev_frame_num        = 0;
 256             h->prev_frame_num_offset = 0;
 257             h->prev_poc_msb          =
 258             h->prev_poc_lsb          = 0;
 259         /* fall through */
 260         case NAL_SLICE:
 261             init_get_bits(&sl->gb, ptr, 8 * dst_length);
 262             get_ue_golomb(&sl->gb);  // skip first_mb_in_slice
 263             slice_type   = get_ue_golomb_31(&sl->gb);
 264             s->pict_type = golomb_to_pict_type[slice_type % 5];
 265             if (h->sei_recovery_frame_cnt >= 0) {
 266                 /* key frame, since recovery_frame_cnt is set */
 267                 s->key_frame = 1;
 268             }
 269             pps_id = get_ue_golomb(&sl->gb);
 270             if (pps_id >= MAX_PPS_COUNT) {
 271                 av_log(h->avctx, AV_LOG_ERROR,
 272                        "pps_id %u out of range\n", pps_id);
 273                 return -1;
 274             }
 275             if (!h->pps_buffers[pps_id]) {
 276                 av_log(h->avctx, AV_LOG_ERROR,
 277                        "non-existing PPS %u referenced\n", pps_id);
 278                 return -1;
 279             }
 280             h->pps = *h->pps_buffers[pps_id];
 281             if (!h->sps_buffers[h->pps.sps_id]) {
 282                 av_log(h->avctx, AV_LOG_ERROR,
 283                        "non-existing SPS %u referenced\n", h->pps.sps_id);
 284                 return -1;
 285             }
 286             h->sps       = *h->sps_buffers[h->pps.sps_id];
 287             h->frame_num = get_bits(&sl->gb, h->sps.log2_max_frame_num);
 288
 289             s->coded_width  = 16 * h->sps.mb_width;
 290             s->coded_height = 16 * h->sps.mb_height;
 291             s->width        = s->coded_width  - (h->sps.crop_right + h->sps.crop_left);
 292             s->height       = s->coded_height - (h->sps.crop_top   + h->sps.crop_bottom);
 293             if (s->width <= 0 || s->height <= 0) {
 294                 s->width  = s->coded_width;
 295                 s->height = s->coded_height;
 296             }
 297
 298             switch (h->sps.bit_depth_luma) {
 299             case 9:
 300                 if (CHROMA444(h))      s->format = AV_PIX_FMT_YUV444P9;
 301                 else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P9;
 302                 else                   s->format = AV_PIX_FMT_YUV420P9;
 303                 break;
 304             case 10:
 305                 if (CHROMA444(h))      s->format = AV_PIX_FMT_YUV444P10;
 306                 else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P10;
 307                 else                   s->format = AV_PIX_FMT_YUV420P10;
 308                 break;
 309             case 8:
 310                 if (CHROMA444(h))      s->format = AV_PIX_FMT_YUV444P;
 311                 else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P;
 312                 else                   s->format = AV_PIX_FMT_YUV420P;
 313                 break;
 314             default:
 315                 s->format = AV_PIX_FMT_NONE;
 316             }
 317
 318             avctx->profile = ff_h264_get_profile(&h->sps);
 319             avctx->level   = h->sps.level_idc;
 320
 321             if (h->sps.frame_mbs_only_flag) {
 322                 h->picture_structure = PICT_FRAME;
 323             } else {
 324                 if (get_bits1(&sl->gb)) { // field_pic_flag
 325                     h->picture_structure = PICT_TOP_FIELD + get_bits1(&sl->gb); // bottom_field_flag
 326                 } else {
 327                     h->picture_structure = PICT_FRAME;
 328                 }
 329             }
 330
 331             if (h->nal_unit_type == NAL_IDR_SLICE)
 332                 get_ue_golomb(&sl->gb); /* idr_pic_id */
 333             if (h->sps.poc_type == 0) {
 334                 h->poc_lsb = get_bits(&sl->gb, h->sps.log2_max_poc_lsb);
 335
 336                 if (h->pps.pic_order_present == 1 &&
 337                     h->picture_structure == PICT_FRAME)
 338                     h->delta_poc_bottom = get_se_golomb(&sl->gb);
 339             }
 340
 341             if (h->sps.poc_type == 1 &&
 342                 !h->sps.delta_pic_order_always_zero_flag) {
 343                 h->delta_poc[0] = get_se_golomb(&sl->gb);
 344
 345                 if (h->pps.pic_order_present == 1 &&
 346                     h->picture_structure == PICT_FRAME)
 347                     h->delta_poc[1] = get_se_golomb(&sl->gb);
 348             }
 349
 350             /* Decode POC of this picture.
 351              * The prev_ values needed for decoding POC of the next picture are not set here. */
 352             field_poc[0] = field_poc[1] = INT_MAX;
 353             ff_init_poc(h, field_poc, &s->output_picture_number);
 354
 355             /* Continue parsing to check if MMCO_RESET is present.
 356              * FIXME: MMCO_RESET could appear in non-first slice.
 357              *        Maybe, we should parse all undisposable non-IDR slice of this
 358              *        picture until encountering MMCO_RESET in a slice of it. */
 359             if (h->nal_ref_idc && h->nal_unit_type != NAL_IDR_SLICE) {
 360                 got_reset = scan_mmco_reset(s);
 361                 if (got_reset < 0)
 362                     return got_reset;
 363             }
 364
 365             /* Set up the prev_ values for decoding POC of the next picture. */
 366             h->prev_frame_num        = got_reset ? 0 : h->frame_num;
 367             h->prev_frame_num_offset = got_reset ? 0 : h->frame_num_offset;
 368             if (h->nal_ref_idc != 0) {
 369                 if (!got_reset) {
 370                     h->prev_poc_msb = h->poc_msb;
 371                     h->prev_poc_lsb = h->poc_lsb;
 372                 } else {
 373                     h->prev_poc_msb = 0;
 374                     h->prev_poc_lsb =
 375                         h->picture_structure == PICT_BOTTOM_FIELD ? 0 : field_poc[0];
 376                 }
 377             }
 378
 379             if (h->sps.pic_struct_present_flag) {
 380                 switch (h->sei_pic_struct) {
 381                 case SEI_PIC_STRUCT_TOP_FIELD:
 382                 case SEI_PIC_STRUCT_BOTTOM_FIELD:
 383                     s->repeat_pict = 0;
 384                     break;
 385                 case SEI_PIC_STRUCT_FRAME:
 386                 case SEI_PIC_STRUCT_TOP_BOTTOM:
 387                 case SEI_PIC_STRUCT_BOTTOM_TOP:
 388                     s->repeat_pict = 1;
 389                     break;
 390                 case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
 391                 case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
 392                     s->repeat_pict = 2;
 393                     break;
 394                 case SEI_PIC_STRUCT_FRAME_DOUBLING:
 395                     s->repeat_pict = 3;
 396                     break;
 397                 case SEI_PIC_STRUCT_FRAME_TRIPLING:
 398                     s->repeat_pict = 5;
 399                     break;
 400                 default:
 401                     s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
 402                     break;
 403                 }
 404             } else {
 405                 s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
 406             }
 407
 408             if (h->picture_structure == PICT_FRAME) {
 409                 s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
 410                 if (h->sps.pic_struct_present_flag) {
 411                     switch (h->sei_pic_struct) {
 412                     case SEI_PIC_STRUCT_TOP_BOTTOM:
 413                     case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
 414                         s->field_order = AV_FIELD_TT;
 415                         break;
 416                     case SEI_PIC_STRUCT_BOTTOM_TOP:
 417                     case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
 418                         s->field_order = AV_FIELD_BB;
 419                         break;
 420                     default:
 421                         s->field_order = AV_FIELD_PROGRESSIVE;
 422                         break;
 423                     }
 424                 } else {
 425                     if (field_poc[0] < field_poc[1])
 426                         s->field_order = AV_FIELD_TT;
 427                     else if (field_poc[0] > field_poc[1])
 428                         s->field_order = AV_FIELD_BB;
 429                     else
 430                         s->field_order = AV_FIELD_PROGRESSIVE;
 431                 }
 432             } else {
 433                 if (h->picture_structure == PICT_TOP_FIELD)
 434                     s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
 435                 else
 436                     s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
 437                 s->field_order = AV_FIELD_UNKNOWN;
 438             }
 439
 440             return 0; /* no need to evaluate the rest */
 441         }
 442         buf += consumed;
 443     }
 444     /* didn't find a picture! */
 445     av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit\n");
 446     return -1;
 447 }
 448
 449 static int h264_parse(AVCodecParserContext *s,
 450                       AVCodecContext *avctx,
 451                       const uint8_t **poutbuf, int *poutbuf_size,
 452                       const uint8_t *buf, int buf_size)
 453 {
 454     H264ParseContext *p = s->priv_data;
 455     H264Context      *h = &p->h;
 456     ParseContext *pc = &p->pc;
 457     int next;
 458
 459     if (!p->got_first) {
 460         p->got_first = 1;
 461         if (avctx->extradata_size) {
 462             h->avctx = avctx;
 463             // must be done like in the decoder.
 464             // otherwise opening the parser, creating extradata,
 465             // and then closing and opening again
 466             // will cause has_b_frames to be always set.
 467             // NB: estimate_timings_from_pts behaves exactly like this.
 468             if (!avctx->has_b_frames)
 469                 h->low_delay = 1;
 470             ff_h264_decode_extradata(h);
 471         }
 472     }
 473
 474     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
 475         next = buf_size;
 476     } else {
 477         next = h264_find_frame_end(p, buf, buf_size);
 478
 479         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
 480             *poutbuf      = NULL;
 481             *poutbuf_size = 0;
 482             return buf_size;
 483         }
 484
 485         if (next < 0 && next != END_NOT_FOUND) {
 486             assert(pc->last_index + next >= 0);
 487             h264_find_frame_end(p, &pc->buffer[pc->last_index + next], -next); // update state
 488         }
 489     }
 490
 491     parse_nal_units(s, avctx, buf, buf_size);
 492
 493     if (h->sei_cpb_removal_delay >= 0) {
 494         s->dts_sync_point    = h->sei_buffering_period_present;
 495         s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
 496         s->pts_dts_delta     = h->sei_dpb_output_delay;
 497     } else {
 498         s->dts_sync_point    = INT_MIN;
 499         s->dts_ref_dts_delta = INT_MIN;
 500         s->pts_dts_delta     = INT_MIN;
 501     }
 502
 503     if (s->flags & PARSER_FLAG_ONCE) {
 504         s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
 505     }
 506
 507     *poutbuf      = buf;
 508     *poutbuf_size = buf_size;
 509     return next;
 510 }
 511
 512 static int h264_split(AVCodecContext *avctx,
 513                       const uint8_t *buf, int buf_size)
 514 {
 515     int i;
 516     uint32_t state = -1;
 517     int has_sps    = 0;
 518
 519     for (i = 0; i <= buf_size; i++) {
 520         if ((state & 0xFFFFFF1F) == 0x107)
 521             has_sps = 1;
 522         /*  if((state&0xFFFFFF1F) == 0x101 ||
 523          *     (state&0xFFFFFF1F) == 0x102 ||
 524          *     (state&0xFFFFFF1F) == 0x105) {
 525          *  }
 526          */
 527         if ((state & 0xFFFFFF00) == 0x100 && (state & 0xFFFFFF1F) != 0x106 &&
 528             (state & 0xFFFFFF1F) != 0x107 && (state & 0xFFFFFF1F) != 0x108 &&
 529             (state & 0xFFFFFF1F) != 0x109 && (state & 0xFFFFFF1F) != 0x10d &&
 530             (state & 0xFFFFFF1F) != 0x10f) {
 531             if (has_sps) {
 532                 while (i > 4 && buf[i - 5] == 0)
 533                     i--;
 534                 return i - 4;
 535             }
 536         }
 537         if (i < buf_size)
 538             state = (state << 8) | buf[i];
 539     }
 540     return 0;
 541 }
 542
 543 static void h264_close(AVCodecParserContext *s)
 544 {
 545     H264ParseContext *p = s->priv_data;
 546     H264Context      *h = &p->h;
 547     ParseContext *pc = &p->pc;
 548
 549     av_free(pc->buffer);
 550     ff_h264_free_context(h);
 551 }
 552
 553 static av_cold int init(AVCodecParserContext *s)
 554 {
 555     H264ParseContext *p = s->priv_data;
 556     H264Context      *h = &p->h;
 557
 558     h->slice_ctx = av_mallocz(sizeof(*h->slice_ctx));
 559     if (!h->slice_ctx)
 560         return 0;
 561     h->nb_slice_ctx = 1;
 562
 563     h->slice_context_count = 1;
 564     ff_h264dsp_init(&h->h264dsp, 8, 1);
 565     return 0;
 566 }
 567
 568 AVCodecParser ff_h264_parser = {
 569     .codec_ids      = { AV_CODEC_ID_H264 },
 570     .priv_data_size = sizeof(H264ParseContext),
 571     .parser_init    = init,
 572     .parser_parse   = h264_parse,
 573     .parser_close   = h264_close,
 574     .split          = h264_split,
 575 };