media/mp2t/es_parser_h264.cc

   1 // Copyright 2013 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 #include "media/mp2t/es_parser_h264.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/logging.h"
   9 #include "media/base/bit_reader.h"
  10 #include "media/base/buffers.h"
  11 #include "media/base/stream_parser_buffer.h"
  12 #include "media/base/video_frame.h"
  13 #include "media/mp2t/mp2t_common.h"
  14 #include "ui/gfx/rect.h"
  15 #include "ui/gfx/size.h"
  16
  17 static const int kExtendedSar = 255;
  18
  19 // ISO 14496 part 10
  20 // VUI parameters: Table E-1 "Meaning of sample aspect ratio indicator"
  21 static const int kSarTableSize = 17;
  22 static const int kTableSarWidth[kSarTableSize] = {
  23   0, 1, 12, 10, 16, 40, 24, 20, 32, 80, 18, 15, 64, 160, 4, 3, 2
  24 };
  25 static const int kTableSarHeight[kSarTableSize] = {
  26   0, 1, 11, 11, 11, 33, 11, 11, 11, 33, 11, 11, 33, 99, 3, 2, 1
  27 };
  28
  29 // Remove the start code emulation prevention ( 0x000003 )
  30 // and return the size of the converted buffer.
  31 // Note: Size of |buf_rbsp| should be at least |size| to accomodate
  32 // the worst case.
  33 static int ConvertToRbsp(const uint8* buf, int size, uint8* buf_rbsp) {
  34   int rbsp_size = 0;
  35   int zero_count = 0;
  36   for (int k = 0; k < size; k++) {
  37     if (buf[k] == 0x3 && zero_count >= 2) {
  38       zero_count = 0;
  39       continue;
  40     }
  41     if (buf[k] == 0)
  42       zero_count++;
  43     else
  44       zero_count = 0;
  45     buf_rbsp[rbsp_size++] = buf[k];
  46   }
  47   return rbsp_size;
  48 }
  49
  50 namespace media {
  51 namespace mp2t {
  52
  53 // ISO 14496 - Part 10: Table 7-1 "NAL unit type codes"
  54 enum NalUnitType {
  55   kNalUnitTypeNonIdrSlice = 1,
  56   kNalUnitTypeIdrSlice = 5,
  57   kNalUnitTypeSPS = 7,
  58   kNalUnitTypePPS = 8,
  59   kNalUnitTypeAUD = 9,
  60 };
  61
  62 class BitReaderH264 : public BitReader {
  63  public:
  64   BitReaderH264(const uint8* data, off_t size)
  65     : BitReader(data, size) { }
  66
  67   // Read an unsigned exp-golomb value.
  68   // Return true if successful.
  69   bool ReadBitsExpGolomb(uint32* exp_golomb_value);
  70 };
  71
  72 bool BitReaderH264::ReadBitsExpGolomb(uint32* exp_golomb_value) {
  73   // Get the number of leading zeros.
  74   int zero_count = 0;
  75   while (true) {
  76     int one_bit;
  77     RCHECK(ReadBits(1, &one_bit));
  78     if (one_bit != 0)
  79       break;
  80     zero_count++;
  81   }
  82
  83   // If zero_count is greater than 31, the calculated value will overflow.
  84   if (zero_count > 31) {
  85     SkipBits(zero_count);
  86     return false;
  87   }
  88
  89   // Read the actual value.
  90   uint32 base = (1 << zero_count) - 1;
  91   uint32 offset;
  92   RCHECK(ReadBits(zero_count, &offset));
  93   *exp_golomb_value = base + offset;
  94
  95   return true;
  96 }
  97
  98 EsParserH264::EsParserH264(
  99     const NewVideoConfigCB& new_video_config_cb,
 100     const EmitBufferCB& emit_buffer_cb)
 101   : new_video_config_cb_(new_video_config_cb),
 102     emit_buffer_cb_(emit_buffer_cb),
 103     es_pos_(0),
 104     current_nal_pos_(-1),
 105     current_access_unit_pos_(-1),
 106     is_key_frame_(false) {
 107 }
 108
 109 EsParserH264::~EsParserH264() {
 110 }
 111
 112 bool EsParserH264::Parse(const uint8* buf, int size,
 113                          base::TimeDelta pts,
 114                          base::TimeDelta dts) {
 115   // Note: Parse is invoked each time a PES packet has been reassembled.
 116   // Unfortunately, a PES packet does not necessarily map
 117   // to an h264 access unit, although the HLS recommendation is to use one PES
 118   // for each access unit (but this is just a recommendation and some streams
 119   // do not comply with this recommendation).
 120
 121   // Link position |raw_es_size| in the ES stream with a timing descriptor.
 122   // HLS recommendation: "In AVC video, you should have both a DTS and a
 123   // PTS in each PES header".
 124   if (dts == kNoTimestamp() && pts == kNoTimestamp()) {
 125     DVLOG(1) << "A timestamp must be provided for each reassembled PES";
 126     return false;
 127   }
 128   TimingDesc timing_desc;
 129   timing_desc.pts = pts;
 130   timing_desc.dts = (dts != kNoTimestamp()) ? dts : pts;
 131
 132   int raw_es_size;
 133   const uint8* raw_es;
 134   es_byte_queue_.Peek(&raw_es, &raw_es_size);
 135   timing_desc_list_.push_back(
 136       std::pair<int, TimingDesc>(raw_es_size, timing_desc));
 137
 138   // Add the incoming bytes to the ES queue.
 139   es_byte_queue_.Push(buf, size);
 140
 141   // Add NALs from the incoming buffer.
 142   if (!ParseInternal())
 143     return false;
 144
 145   // Discard emitted frames
 146   // or every byte that was parsed so far if there is no current frame.
 147   int skip_count =
 148       (current_access_unit_pos_ >= 0) ? current_access_unit_pos_ : es_pos_;
 149   DiscardEs(skip_count);
 150
 151   return true;
 152 }
 153
 154 void EsParserH264::Flush() {
 155   if (current_access_unit_pos_ < 0)
 156     return;
 157
 158   // Force emitting the last access unit.
 159   int next_aud_pos;
 160   const uint8* raw_es;
 161   es_byte_queue_.Peek(&raw_es, &next_aud_pos);
 162   EmitFrameIfNeeded(next_aud_pos);
 163   current_nal_pos_ = -1;
 164   StartFrame(-1);
 165
 166   // Discard the emitted frame.
 167   DiscardEs(next_aud_pos);
 168 }
 169
 170 void EsParserH264::Reset() {
 171   DVLOG(1) << "EsParserH264::Reset";
 172   es_byte_queue_.Reset();
 173   timing_desc_list_.clear();
 174   es_pos_ = 0;
 175   current_nal_pos_ = -1;
 176   StartFrame(-1);
 177   last_video_decoder_config_ = VideoDecoderConfig();
 178 }
 179
 180 bool EsParserH264::ParseInternal() {
 181   int raw_es_size;
 182   const uint8* raw_es;
 183   es_byte_queue_.Peek(&raw_es, &raw_es_size);
 184
 185   DCHECK_GE(es_pos_, 0);
 186   DCHECK_LT(es_pos_, raw_es_size);
 187
 188   // Resume h264 es parsing where it was left.
 189   for ( ; es_pos_ < raw_es_size - 4; es_pos_++) {
 190     // Make sure the syncword is either 00 00 00 01 or 00 00 01
 191     if (raw_es[es_pos_ + 0] != 0 || raw_es[es_pos_ + 1] != 0)
 192       continue;
 193     int syncword_length = 0;
 194     if (raw_es[es_pos_ + 2] == 0 && raw_es[es_pos_ + 3] == 1)
 195       syncword_length = 4;
 196     else if (raw_es[es_pos_ + 2] == 1)
 197       syncword_length = 3;
 198     else
 199       continue;
 200
 201     // Parse the current NAL (and the new NAL then becomes the current one).
 202     if (current_nal_pos_ >= 0) {
 203       int nal_size = es_pos_ - current_nal_pos_;
 204       DCHECK_GT(nal_size, 0);
 205       RCHECK(NalParser(&raw_es[current_nal_pos_], nal_size));
 206     }
 207     current_nal_pos_ = es_pos_ + syncword_length;
 208
 209     // Retrieve the NAL type.
 210     int nal_header = raw_es[current_nal_pos_];
 211     int forbidden_zero_bit = (nal_header >> 7) & 0x1;
 212     RCHECK(forbidden_zero_bit == 0);
 213     NalUnitType nal_unit_type = static_cast<NalUnitType>(nal_header & 0x1f);
 214     DVLOG(LOG_LEVEL_ES) << "nal: offset=" << es_pos_
 215                         << " type=" << nal_unit_type;
 216
 217     // Emit a frame if needed.
 218     if (nal_unit_type == kNalUnitTypeAUD)
 219       EmitFrameIfNeeded(es_pos_);
 220
 221     // Skip the syncword.
 222     es_pos_ += syncword_length;
 223   }
 224
 225   return true;
 226 }
 227
 228 void EsParserH264::EmitFrameIfNeeded(int next_aud_pos) {
 229   // There is no current frame: start a new frame.
 230   if (current_access_unit_pos_ < 0) {
 231     StartFrame(next_aud_pos);
 232     return;
 233   }
 234
 235   // Get the access unit timing info.
 236   TimingDesc current_timing_desc;
 237   while (!timing_desc_list_.empty() &&
 238          timing_desc_list_.front().first <= current_access_unit_pos_) {
 239     current_timing_desc = timing_desc_list_.front().second;
 240     timing_desc_list_.pop_front();
 241   }
 242
 243   // Emit a frame.
 244   int raw_es_size;
 245   const uint8* raw_es;
 246   es_byte_queue_.Peek(&raw_es, &raw_es_size);
 247   int access_unit_size = next_aud_pos - current_access_unit_pos_;
 248   scoped_refptr<StreamParserBuffer> stream_parser_buffer =
 249       StreamParserBuffer::CopyFrom(
 250           &raw_es[current_access_unit_pos_],
 251           access_unit_size,
 252           is_key_frame_);
 253   stream_parser_buffer->SetDecodeTimestamp(current_timing_desc.dts);
 254   stream_parser_buffer->set_timestamp(current_timing_desc.pts);
 255   emit_buffer_cb_.Run(stream_parser_buffer);
 256
 257   // Set the current frame position to the next AUD position.
 258   StartFrame(next_aud_pos);
 259 }
 260
 261 void EsParserH264::StartFrame(int aud_pos) {
 262   // Two cases:
 263   // - if aud_pos < 0, clear the current frame and set |is_key_frame| to a
 264   // default value (false).
 265   // - if aud_pos >= 0, start a new frame and set |is_key_frame| to true
 266   // |is_key_frame_| will be updated while parsing the NALs of that frame.
 267   // If any NAL is a non IDR NAL, it will be set to false.
 268   current_access_unit_pos_ = aud_pos;
 269   is_key_frame_ = (aud_pos >= 0);
 270 }
 271
 272 void EsParserH264::DiscardEs(int nbytes) {
 273   DCHECK_GE(nbytes, 0);
 274   if (nbytes == 0)
 275     return;
 276
 277   // Update the position of
 278   // - the parser,
 279   // - the current NAL,
 280   // - the current access unit.
 281   es_pos_ -= nbytes;
 282   if (es_pos_ < 0)
 283     es_pos_ = 0;
 284
 285   if (current_nal_pos_ >= 0) {
 286     DCHECK_GE(current_nal_pos_, nbytes);
 287     current_nal_pos_ -= nbytes;
 288   }
 289   if (current_access_unit_pos_ >= 0) {
 290     DCHECK_GE(current_access_unit_pos_, nbytes);
 291     current_access_unit_pos_ -= nbytes;
 292   }
 293
 294   // Update the timing information accordingly.
 295   std::list<std::pair<int, TimingDesc> >::iterator timing_it
 296       = timing_desc_list_.begin();
 297   for (; timing_it != timing_desc_list_.end(); ++timing_it)
 298     timing_it->first -= nbytes;
 299
 300   // Discard |nbytes| of ES.
 301   es_byte_queue_.Pop(nbytes);
 302 }
 303
 304 bool EsParserH264::NalParser(const uint8* buf, int size) {
 305   // Get the NAL header.
 306   if (size < 1) {
 307     DVLOG(1) << "NalParser: incomplete NAL";
 308     return false;
 309   }
 310   int nal_header = buf[0];
 311   buf += 1;
 312   size -= 1;
 313
 314   int forbidden_zero_bit = (nal_header >> 7) & 0x1;
 315   if (forbidden_zero_bit != 0)
 316     return false;
 317   int nal_ref_idc = (nal_header >> 5) & 0x3;
 318   int nal_unit_type = nal_header & 0x1f;
 319
 320   // Process the NAL content.
 321   switch (nal_unit_type) {
 322     case kNalUnitTypeSPS:
 323       DVLOG(LOG_LEVEL_ES) << "NAL: SPS";
 324       // |nal_ref_idc| should not be 0 for a SPS.
 325       if (nal_ref_idc == 0)
 326         return false;
 327       return ProcessSPS(buf, size);
 328     case kNalUnitTypeIdrSlice:
 329       DVLOG(LOG_LEVEL_ES) << "NAL: IDR slice";
 330       return true;
 331     case kNalUnitTypeNonIdrSlice:
 332       DVLOG(LOG_LEVEL_ES) << "NAL: Non IDR slice";
 333       is_key_frame_ = false;
 334       return true;
 335     case kNalUnitTypePPS:
 336       DVLOG(LOG_LEVEL_ES) << "NAL: PPS";
 337       return true;
 338     case  kNalUnitTypeAUD:
 339       DVLOG(LOG_LEVEL_ES) << "NAL: AUD";
 340       return true;
 341     default:
 342       DVLOG(LOG_LEVEL_ES) << "NAL: " << nal_unit_type;
 343       return true;
 344   }
 345
 346   NOTREACHED();
 347   return false;
 348 }
 349
 350 bool EsParserH264::ProcessSPS(const uint8* buf, int size) {
 351   if (size <= 0)
 352     return false;
 353
 354   // Removes start code emulation prevention.
 355   // TODO(damienv): refactoring in media/base
 356   // so as to have a unique H264 bit reader in Chrome.
 357   scoped_ptr<uint8[]> buf_rbsp(new uint8[size]);
 358   int rbsp_size = ConvertToRbsp(buf, size, buf_rbsp.get());
 359
 360   BitReaderH264 bit_reader(buf_rbsp.get(), rbsp_size);
 361
 362   int profile_idc;
 363   int constraint_setX_flag;
 364   int level_idc;
 365   uint32 seq_parameter_set_id;
 366   uint32 log2_max_frame_num_minus4;
 367   uint32 pic_order_cnt_type;
 368   RCHECK(bit_reader.ReadBits(8, &profile_idc));
 369   RCHECK(bit_reader.ReadBits(8, &constraint_setX_flag));
 370   RCHECK(bit_reader.ReadBits(8, &level_idc));
 371   RCHECK(bit_reader.ReadBitsExpGolomb(&seq_parameter_set_id));
 372
 373   if (profile_idc == 100 || profile_idc == 110 ||
 374       profile_idc == 122 || profile_idc == 244 ||
 375       profile_idc ==  44 || profile_idc ==  83 ||
 376       profile_idc ==  86 || profile_idc == 118 ||
 377       profile_idc == 128) {
 378     uint32 chroma_format_idc;
 379     RCHECK(bit_reader.ReadBitsExpGolomb(&chroma_format_idc));
 380     if (chroma_format_idc == 3) {
 381       int separate_colour_plane_flag;
 382       RCHECK(bit_reader.ReadBits(1, &separate_colour_plane_flag));
 383     }
 384     uint32 bit_depth_luma_minus8;
 385     uint32 bit_depth_chroma_minus8;
 386     int qpprime_y_zero_transform_bypass_flag;
 387     int seq_scaling_matrix_present_flag;
 388     RCHECK(bit_reader.ReadBitsExpGolomb(&bit_depth_luma_minus8));
 389     RCHECK(bit_reader.ReadBitsExpGolomb(&bit_depth_chroma_minus8));
 390     RCHECK(bit_reader.ReadBits(1, &qpprime_y_zero_transform_bypass_flag));
 391     RCHECK(bit_reader.ReadBits(1, &seq_scaling_matrix_present_flag));
 392     if (seq_scaling_matrix_present_flag) {
 393       int skip_count = (chroma_format_idc != 3) ? 8 : 12;
 394       RCHECK(bit_reader.SkipBits(skip_count));
 395     }
 396   }
 397
 398   RCHECK(bit_reader.ReadBitsExpGolomb(&log2_max_frame_num_minus4));
 399   RCHECK(bit_reader.ReadBitsExpGolomb(&pic_order_cnt_type));
 400
 401   // |pic_order_cnt_type| shall be in the range of 0 to 2.
 402   RCHECK(pic_order_cnt_type <= 2);
 403   if (pic_order_cnt_type == 0) {
 404     uint32 log2_max_pic_order_cnt_lsb_minus4;
 405     RCHECK(bit_reader.ReadBitsExpGolomb(&log2_max_pic_order_cnt_lsb_minus4));
 406   } else if (pic_order_cnt_type == 1) {
 407     // Note: |offset_for_non_ref_pic| and |offset_for_top_to_bottom_field|
 408     // corresponds to their codenum not to their actual value.
 409     int delta_pic_order_always_zero_flag;
 410     uint32 offset_for_non_ref_pic;
 411     uint32 offset_for_top_to_bottom_field;
 412     uint32 num_ref_frames_in_pic_order_cnt_cycle;
 413     RCHECK(bit_reader.ReadBits(1, &delta_pic_order_always_zero_flag));
 414     RCHECK(bit_reader.ReadBitsExpGolomb(&offset_for_non_ref_pic));
 415     RCHECK(bit_reader.ReadBitsExpGolomb(&offset_for_top_to_bottom_field));
 416     RCHECK(
 417         bit_reader.ReadBitsExpGolomb(&num_ref_frames_in_pic_order_cnt_cycle));
 418     for (uint32 i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++) {
 419       uint32 offset_for_ref_frame_codenum;
 420       RCHECK(bit_reader.ReadBitsExpGolomb(&offset_for_ref_frame_codenum));
 421     }
 422   }
 423
 424   uint32 num_ref_frames;
 425   int gaps_in_frame_num_value_allowed_flag;
 426   uint32 pic_width_in_mbs_minus1;
 427   uint32 pic_height_in_map_units_minus1;
 428   RCHECK(bit_reader.ReadBitsExpGolomb(&num_ref_frames));
 429   RCHECK(bit_reader.ReadBits(1, &gaps_in_frame_num_value_allowed_flag));
 430   RCHECK(bit_reader.ReadBitsExpGolomb(&pic_width_in_mbs_minus1));
 431   RCHECK(bit_reader.ReadBitsExpGolomb(&pic_height_in_map_units_minus1));
 432
 433   int frame_mbs_only_flag;
 434   RCHECK(bit_reader.ReadBits(1, &frame_mbs_only_flag));
 435   if (!frame_mbs_only_flag) {
 436     int mb_adaptive_frame_field_flag;
 437     RCHECK(bit_reader.ReadBits(1, &mb_adaptive_frame_field_flag));
 438   }
 439
 440   int direct_8x8_inference_flag;
 441   RCHECK(bit_reader.ReadBits(1, &direct_8x8_inference_flag));
 442
 443   int frame_cropping_flag;
 444   uint32 frame_crop_left_offset = 0;
 445   uint32 frame_crop_right_offset = 0;
 446   uint32 frame_crop_top_offset = 0;
 447   uint32 frame_crop_bottom_offset = 0;
 448   RCHECK(bit_reader.ReadBits(1, &frame_cropping_flag));
 449   if (frame_cropping_flag) {
 450     RCHECK(bit_reader.ReadBitsExpGolomb(&frame_crop_left_offset));
 451     RCHECK(bit_reader.ReadBitsExpGolomb(&frame_crop_right_offset));
 452     RCHECK(bit_reader.ReadBitsExpGolomb(&frame_crop_top_offset));
 453     RCHECK(bit_reader.ReadBitsExpGolomb(&frame_crop_bottom_offset));
 454   }
 455
 456   int vui_parameters_present_flag;
 457   RCHECK(bit_reader.ReadBits(1, &vui_parameters_present_flag));
 458   int sar_width = 1;
 459   int sar_height = 1;
 460   if (vui_parameters_present_flag) {
 461     // Read only the aspect ratio information from the VUI section.
 462     // TODO(damienv): check whether other VUI info are useful.
 463     int aspect_ratio_info_present_flag;
 464     RCHECK(bit_reader.ReadBits(1, &aspect_ratio_info_present_flag));
 465     if (aspect_ratio_info_present_flag) {
 466       int aspect_ratio_idc;
 467       RCHECK(bit_reader.ReadBits(8, &aspect_ratio_idc));
 468       if (aspect_ratio_idc == kExtendedSar) {
 469         RCHECK(bit_reader.ReadBits(16, &sar_width));
 470         RCHECK(bit_reader.ReadBits(16, &sar_height));
 471       } else if (aspect_ratio_idc < kSarTableSize) {
 472         sar_width = kTableSarWidth[aspect_ratio_idc];
 473         sar_height = kTableSarHeight[aspect_ratio_idc];
 474       }
 475     }
 476   }
 477
 478   if (sar_width == 0 || sar_height == 0) {
 479     DVLOG(1) << "Unspecified SAR not supported";
 480     return false;
 481   }
 482
 483   // TODO(damienv): a MAP unit can be either 16 or 32 pixels.
 484   // although it's 16 pixels for progressive non MBAFF frames.
 485   gfx::Size coded_size((pic_width_in_mbs_minus1 + 1) * 16,
 486                        (pic_height_in_map_units_minus1 + 1) * 16);
 487   gfx::Rect visible_rect(
 488       frame_crop_left_offset,
 489       frame_crop_top_offset,
 490       (coded_size.width() - frame_crop_right_offset) - frame_crop_left_offset,
 491       (coded_size.height() - frame_crop_bottom_offset) - frame_crop_top_offset);
 492   if (visible_rect.width() <= 0 || visible_rect.height() <= 0)
 493     return false;
 494   gfx::Size natural_size((visible_rect.width() * sar_width) / sar_height,
 495                          visible_rect.height());
 496   if (natural_size.width() == 0)
 497     return false;
 498
 499   // TODO(damienv):
 500   // Assuming the SPS is used right away by the PPS
 501   // and the slice headers is a strong assumption.
 502   // In theory, we should process the SPS and PPS
 503   // and only when one of the slice header is switching
 504   // the PPS id, the video decoder config should be changed.
 505   VideoDecoderConfig video_decoder_config(
 506       kCodecH264,
 507       VIDEO_CODEC_PROFILE_UNKNOWN,    // TODO(damienv)
 508       VideoFrame::YV12,
 509       coded_size,
 510       visible_rect,
 511       natural_size,
 512       NULL, 0,
 513       false);
 514
 515   if (!video_decoder_config.Matches(last_video_decoder_config_)) {
 516     DVLOG(1) << "Profile IDC: " << profile_idc;
 517     DVLOG(1) << "Level IDC: " << level_idc;
 518     DVLOG(1) << "Pic width: " << (pic_width_in_mbs_minus1 + 1) * 16;
 519     DVLOG(1) << "Pic height: " << (pic_height_in_map_units_minus1 + 1) * 16;
 520     DVLOG(1) << "log2_max_frame_num_minus4: " << log2_max_frame_num_minus4;
 521     DVLOG(1) << "SAR: width=" << sar_width << " height=" << sar_height;
 522     last_video_decoder_config_ = video_decoder_config;
 523     new_video_config_cb_.Run(video_decoder_config);
 524   }
 525
 526   return true;
 527 }
 528
 529 }  // namespace mp2t
 530 }  // namespace media
 531