media/filters/h264_parser.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4 //
   5 // This file contains an implementation of an H264 Annex-B video stream parser.
   6
   7 #ifndef MEDIA_FILTERS_H264_PARSER_H_
   8 #define MEDIA_FILTERS_H264_PARSER_H_
   9
  10 #include <sys/types.h>
  11
  12 #include <map>
  13
  14 #include "base/basictypes.h"
  15 #include "media/base/media_export.h"
  16 #include "media/filters/h264_bit_reader.h"
  17
  18 namespace media {
  19
  20 // For explanations of each struct and its members, see H.264 specification
  21 // at http://www.itu.int/rec/T-REC-H.264.
  22 struct MEDIA_EXPORT H264NALU {
  23   H264NALU();
  24
  25   enum Type {
  26     kUnspecified = 0,
  27     kNonIDRSlice = 1,
  28     kSliceDataA = 2,
  29     kSliceDataB = 3,
  30     kSliceDataC = 4,
  31     kIDRSlice = 5,
  32     kSEIMessage = 6,
  33     kSPS = 7,
  34     kPPS = 8,
  35     kAUD = 9,
  36     kEOSeq = 10,
  37     kEOStream = 11,
  38     kFiller = 12,
  39     kSPSExt = 13,
  40     kReserved14 = 14,
  41     kReserved15 = 15,
  42     kReserved16 = 16,
  43     kReserved17 = 17,
  44     kReserved18 = 18,
  45     kCodedSliceAux = 19,
  46     kCodedSliceExtension = 20,
  47   };
  48
  49   // After (without) start code; we don't own the underlying memory
  50   // and a shallow copy should be made when copying this struct.
  51   const uint8* data;
  52   off_t size;  // From after start code to start code of next NALU (or EOS).
  53
  54   int nal_ref_idc;
  55   int nal_unit_type;
  56 };
  57
  58 enum {
  59   kH264ScalingList4x4Length = 16,
  60   kH264ScalingList8x8Length = 64,
  61 };
  62
  63 struct MEDIA_EXPORT H264SPS {
  64   H264SPS();
  65
  66   int profile_idc;
  67   bool constraint_set0_flag;
  68   bool constraint_set1_flag;
  69   bool constraint_set2_flag;
  70   bool constraint_set3_flag;
  71   bool constraint_set4_flag;
  72   bool constraint_set5_flag;
  73   int level_idc;
  74   int seq_parameter_set_id;
  75
  76   int chroma_format_idc;
  77   bool separate_colour_plane_flag;
  78   int bit_depth_luma_minus8;
  79   int bit_depth_chroma_minus8;
  80   bool qpprime_y_zero_transform_bypass_flag;
  81
  82   bool seq_scaling_matrix_present_flag;
  83   int scaling_list4x4[6][kH264ScalingList4x4Length];
  84   int scaling_list8x8[6][kH264ScalingList8x8Length];
  85
  86   int log2_max_frame_num_minus4;
  87   int pic_order_cnt_type;
  88   int log2_max_pic_order_cnt_lsb_minus4;
  89   bool delta_pic_order_always_zero_flag;
  90   int offset_for_non_ref_pic;
  91   int offset_for_top_to_bottom_field;
  92   int num_ref_frames_in_pic_order_cnt_cycle;
  93   int expected_delta_per_pic_order_cnt_cycle;  // calculated
  94   int offset_for_ref_frame[255];
  95   int max_num_ref_frames;
  96   bool gaps_in_frame_num_value_allowed_flag;
  97   int pic_width_in_mbs_minus1;
  98   int pic_height_in_map_units_minus1;
  99   bool frame_mbs_only_flag;
 100   bool mb_adaptive_frame_field_flag;
 101   bool direct_8x8_inference_flag;
 102   bool frame_cropping_flag;
 103   int frame_crop_left_offset;
 104   int frame_crop_right_offset;
 105   int frame_crop_top_offset;
 106   int frame_crop_bottom_offset;
 107
 108   bool vui_parameters_present_flag;
 109   int sar_width;    // Set to 0 when not specified.
 110   int sar_height;   // Set to 0 when not specified.
 111   bool bitstream_restriction_flag;
 112   int max_num_reorder_frames;
 113   int max_dec_frame_buffering;
 114
 115   int chroma_array_type;
 116 };
 117
 118 struct MEDIA_EXPORT H264PPS {
 119   H264PPS();
 120
 121   int pic_parameter_set_id;
 122   int seq_parameter_set_id;
 123   bool entropy_coding_mode_flag;
 124   bool bottom_field_pic_order_in_frame_present_flag;
 125   int num_slice_groups_minus1;
 126   // TODO(posciak): Slice groups not implemented, could be added at some point.
 127   int num_ref_idx_l0_default_active_minus1;
 128   int num_ref_idx_l1_default_active_minus1;
 129   bool weighted_pred_flag;
 130   int weighted_bipred_idc;
 131   int pic_init_qp_minus26;
 132   int pic_init_qs_minus26;
 133   int chroma_qp_index_offset;
 134   bool deblocking_filter_control_present_flag;
 135   bool constrained_intra_pred_flag;
 136   bool redundant_pic_cnt_present_flag;
 137   bool transform_8x8_mode_flag;
 138
 139   bool pic_scaling_matrix_present_flag;
 140   int scaling_list4x4[6][kH264ScalingList4x4Length];
 141   int scaling_list8x8[6][kH264ScalingList8x8Length];
 142
 143   int second_chroma_qp_index_offset;
 144 };
 145
 146 struct MEDIA_EXPORT H264ModificationOfPicNum {
 147   int modification_of_pic_nums_idc;
 148   union {
 149     int abs_diff_pic_num_minus1;
 150     int long_term_pic_num;
 151   };
 152 };
 153
 154 struct MEDIA_EXPORT H264WeightingFactors {
 155   bool luma_weight_flag;
 156   bool chroma_weight_flag;
 157   int luma_weight[32];
 158   int luma_offset[32];
 159   int chroma_weight[32][2];
 160   int chroma_offset[32][2];
 161 };
 162
 163 struct MEDIA_EXPORT H264DecRefPicMarking {
 164   int memory_mgmnt_control_operation;
 165   int difference_of_pic_nums_minus1;
 166   int long_term_pic_num;
 167   int long_term_frame_idx;
 168   int max_long_term_frame_idx_plus1;
 169 };
 170
 171 struct MEDIA_EXPORT H264SliceHeader {
 172   H264SliceHeader();
 173
 174   enum {
 175     kRefListSize = 32,
 176     kRefListModSize = kRefListSize
 177   };
 178
 179   enum Type {
 180     kPSlice = 0,
 181     kBSlice = 1,
 182     kISlice = 2,
 183     kSPSlice = 3,
 184     kSISlice = 4,
 185   };
 186
 187   bool IsPSlice() const;
 188   bool IsBSlice() const;
 189   bool IsISlice() const;
 190   bool IsSPSlice() const;
 191   bool IsSISlice() const;
 192
 193   bool idr_pic_flag;       // from NAL header
 194   int nal_ref_idc;         // from NAL header
 195   const uint8* nalu_data;  // from NAL header
 196   off_t nalu_size;         // from NAL header
 197   off_t header_bit_size;   // calculated
 198
 199   int first_mb_in_slice;
 200   int slice_type;
 201   int pic_parameter_set_id;
 202   int colour_plane_id;  // TODO(posciak): use this!  http://crbug.com/139878
 203   int frame_num;
 204   bool field_pic_flag;
 205   bool bottom_field_flag;
 206   int idr_pic_id;
 207   int pic_order_cnt_lsb;
 208   int delta_pic_order_cnt_bottom;
 209   int delta_pic_order_cnt[2];
 210   int redundant_pic_cnt;
 211   bool direct_spatial_mv_pred_flag;
 212
 213   bool num_ref_idx_active_override_flag;
 214   int num_ref_idx_l0_active_minus1;
 215   int num_ref_idx_l1_active_minus1;
 216   bool ref_pic_list_modification_flag_l0;
 217   bool ref_pic_list_modification_flag_l1;
 218   H264ModificationOfPicNum ref_list_l0_modifications[kRefListModSize];
 219   H264ModificationOfPicNum ref_list_l1_modifications[kRefListModSize];
 220
 221   int luma_log2_weight_denom;
 222   int chroma_log2_weight_denom;
 223
 224   bool luma_weight_l0_flag;
 225   bool chroma_weight_l0_flag;
 226   H264WeightingFactors pred_weight_table_l0;
 227
 228   bool luma_weight_l1_flag;
 229   bool chroma_weight_l1_flag;
 230   H264WeightingFactors pred_weight_table_l1;
 231
 232   bool no_output_of_prior_pics_flag;
 233   bool long_term_reference_flag;
 234
 235   bool adaptive_ref_pic_marking_mode_flag;
 236   H264DecRefPicMarking ref_pic_marking[kRefListSize];
 237
 238   int cabac_init_idc;
 239   int slice_qp_delta;
 240   bool sp_for_switch_flag;
 241   int slice_qs_delta;
 242   int disable_deblocking_filter_idc;
 243   int slice_alpha_c0_offset_div2;
 244   int slice_beta_offset_div2;
 245 };
 246
 247 struct H264SEIRecoveryPoint {
 248   int recovery_frame_cnt;
 249   bool exact_match_flag;
 250   bool broken_link_flag;
 251   int changing_slice_group_idc;
 252 };
 253
 254 struct MEDIA_EXPORT H264SEIMessage {
 255   H264SEIMessage();
 256
 257   enum Type {
 258     kSEIRecoveryPoint = 6,
 259   };
 260
 261   int type;
 262   int payload_size;
 263   union {
 264     // Placeholder; in future more supported types will contribute to more
 265     // union members here.
 266     H264SEIRecoveryPoint recovery_point;
 267   };
 268 };
 269
 270 // Class to parse an Annex-B H.264 stream,
 271 // as specified in chapters 7 and Annex B of the H.264 spec.
 272 class MEDIA_EXPORT H264Parser {
 273  public:
 274   enum Result {
 275     kOk,
 276     kInvalidStream,      // error in stream
 277     kUnsupportedStream,  // stream not supported by the parser
 278     kEOStream,           // end of stream
 279   };
 280
 281   // Find offset from start of data to next NALU start code
 282   // and size of found start code (3 or 4 bytes).
 283   // If no start code is found, offset is pointing to the first unprocessed byte
 284   // (i.e. the first byte that was not considered as a possible start of a start
 285   // code) and |*start_code_size| is set to 0.
 286   // Preconditions:
 287   // - |data_size| >= 0
 288   // Postconditions:
 289   // - |*offset| is between 0 and |data_size| included.
 290   //   It is strictly less than |data_size| if |data_size| > 0.
 291   // - |*start_code_size| is either 0, 3 or 4.
 292   static bool FindStartCode(const uint8* data, off_t data_size,
 293                             off_t* offset, off_t* start_code_size);
 294
 295   H264Parser();
 296   ~H264Parser();
 297
 298   void Reset();
 299   // Set current stream pointer to |stream| of |stream_size| in bytes,
 300   // |stream| owned by caller.
 301   void SetStream(const uint8* stream, off_t stream_size);
 302
 303   // Read the stream to find the next NALU, identify it and return
 304   // that information in |*nalu|. This advances the stream to the beginning
 305   // of this NALU, but not past it, so subsequent calls to NALU-specific
 306   // parsing functions (ParseSPS, etc.)  will parse this NALU.
 307   // If the caller wishes to skip the current NALU, it can call this function
 308   // again, instead of any NALU-type specific parse functions below.
 309   Result AdvanceToNextNALU(H264NALU* nalu);
 310
 311   // NALU-specific parsing functions.
 312   // These should be called after AdvanceToNextNALU().
 313
 314   // SPSes and PPSes are owned by the parser class and the memory for their
 315   // structures is managed here, not by the caller, as they are reused
 316   // across NALUs.
 317   //
 318   // Parse an SPS/PPS NALU and save their data in the parser, returning id
 319   // of the parsed structure in |*pps_id|/|*sps_id|.
 320   // To get a pointer to a given SPS/PPS structure, use GetSPS()/GetPPS(),
 321   // passing the returned |*sps_id|/|*pps_id| as parameter.
 322   // TODO(posciak,fischman): consider replacing returning Result from Parse*()
 323   // methods with a scoped_ptr and adding an AtEOS() function to check for EOS
 324   // if Parse*() return NULL.
 325   Result ParseSPS(int* sps_id);
 326   Result ParsePPS(int* pps_id);
 327
 328   // Return a pointer to SPS/PPS with given |sps_id|/|pps_id| or NULL if not
 329   // present.
 330   const H264SPS* GetSPS(int sps_id);
 331   const H264PPS* GetPPS(int pps_id);
 332
 333   // Slice headers and SEI messages are not used across NALUs by the parser
 334   // and can be discarded after current NALU, so the parser does not store
 335   // them, nor does it manage their memory.
 336   // The caller has to provide and manage it instead.
 337
 338   // Parse a slice header, returning it in |*shdr|. |*nalu| must be set to
 339   // the NALU returned from AdvanceToNextNALU() and corresponding to |*shdr|.
 340   Result ParseSliceHeader(const H264NALU& nalu, H264SliceHeader* shdr);
 341
 342   // Parse a SEI message, returning it in |*sei_msg|, provided and managed
 343   // by the caller.
 344   Result ParseSEI(H264SEIMessage* sei_msg);
 345
 346  private:
 347   // Move the stream pointer to the beginning of the next NALU,
 348   // i.e. pointing at the next start code.
 349   // Return true if a NALU has been found.
 350   // If a NALU is found:
 351   // - its size in bytes is returned in |*nalu_size| and includes
 352   //   the start code as well as the trailing zero bits.
 353   // - the size in bytes of the start code is returned in |*start_code_size|.
 354   bool LocateNALU(off_t* nalu_size, off_t* start_code_size);
 355
 356   // Exp-Golomb code parsing as specified in chapter 9.1 of the spec.
 357   // Read one unsigned exp-Golomb code from the stream and return in |*val|.
 358   Result ReadUE(int* val);
 359
 360   // Read one signed exp-Golomb code from the stream and return in |*val|.
 361   Result ReadSE(int* val);
 362
 363   // Parse scaling lists (see spec).
 364   Result ParseScalingList(int size, int* scaling_list, bool* use_default);
 365   Result ParseSPSScalingLists(H264SPS* sps);
 366   Result ParsePPSScalingLists(const H264SPS& sps, H264PPS* pps);
 367
 368   // Parse optional VUI parameters in SPS (see spec).
 369   Result ParseVUIParameters(H264SPS* sps);
 370   // Set |hrd_parameters_present| to true only if they are present.
 371   Result ParseAndIgnoreHRDParameters(bool* hrd_parameters_present);
 372
 373   // Parse reference picture lists' modifications (see spec).
 374   Result ParseRefPicListModifications(H264SliceHeader* shdr);
 375   Result ParseRefPicListModification(int num_ref_idx_active_minus1,
 376                                      H264ModificationOfPicNum* ref_list_mods);
 377
 378   // Parse prediction weight table (see spec).
 379   Result ParsePredWeightTable(const H264SPS& sps, H264SliceHeader* shdr);
 380
 381   // Parse weighting factors (see spec).
 382   Result ParseWeightingFactors(int num_ref_idx_active_minus1,
 383                                int chroma_array_type,
 384                                int luma_log2_weight_denom,
 385                                int chroma_log2_weight_denom,
 386                                H264WeightingFactors* w_facts);
 387
 388   // Parse decoded reference picture marking information (see spec).
 389   Result ParseDecRefPicMarking(H264SliceHeader* shdr);
 390
 391   // Pointer to the current NALU in the stream.
 392   const uint8* stream_;
 393
 394   // Bytes left in the stream after the current NALU.
 395   off_t bytes_left_;
 396
 397   H264BitReader br_;
 398
 399   // PPSes and SPSes stored for future reference.
 400   typedef std::map<int, H264SPS*> SPSById;
 401   typedef std::map<int, H264PPS*> PPSById;
 402   SPSById active_SPSes_;
 403   PPSById active_PPSes_;
 404
 405   DISALLOW_COPY_AND_ASSIGN(H264Parser);
 406 };
 407
 408 }  // namespace media
 409
 410 #endif  // MEDIA_FILTERS_H264_PARSER_H_