media/formats/mp4/mp4_stream_parser.cc

   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 #include "media/formats/mp4/mp4_stream_parser.h"
   6
   7 #include "base/callback.h"
   8 #include "base/callback_helpers.h"
   9 #include "base/logging.h"
  10 #include "base/time/time.h"
  11 #include "media/base/audio_decoder_config.h"
  12 #include "media/base/stream_parser_buffer.h"
  13 #include "media/base/text_track_config.h"
  14 #include "media/base/video_decoder_config.h"
  15 #include "media/base/video_util.h"
  16 #include "media/formats/mp4/box_definitions.h"
  17 #include "media/formats/mp4/box_reader.h"
  18 #include "media/formats/mp4/es_descriptor.h"
  19 #include "media/formats/mp4/rcheck.h"
  20 #include "media/formats/mpeg/adts_constants.h"
  21
  22 namespace media {
  23 namespace mp4 {
  24
  25 static const char kCencInitDataType[] = "cenc";
  26
  27 MP4StreamParser::MP4StreamParser(const std::set<int>& audio_object_types,
  28                                  bool has_sbr)
  29     : state_(kWaitingForInit),
  30       moof_head_(0),
  31       mdat_tail_(0),
  32       highest_end_offset_(0),
  33       has_audio_(false),
  34       has_video_(false),
  35       audio_track_id_(0),
  36       video_track_id_(0),
  37       audio_object_types_(audio_object_types),
  38       has_sbr_(has_sbr),
  39       is_audio_track_encrypted_(false),
  40       is_video_track_encrypted_(false) {
  41 }
  42
  43 MP4StreamParser::~MP4StreamParser() {}
  44
  45 void MP4StreamParser::Init(
  46     const InitCB& init_cb,
  47     const NewConfigCB& config_cb,
  48     const NewBuffersCB& new_buffers_cb,
  49     bool /* ignore_text_tracks */,
  50     const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
  51     const NewMediaSegmentCB& new_segment_cb,
  52     const base::Closure& end_of_segment_cb,
  53     const LogCB& log_cb) {
  54   DCHECK_EQ(state_, kWaitingForInit);
  55   DCHECK(init_cb_.is_null());
  56   DCHECK(!init_cb.is_null());
  57   DCHECK(!config_cb.is_null());
  58   DCHECK(!new_buffers_cb.is_null());
  59   DCHECK(!encrypted_media_init_data_cb.is_null());
  60   DCHECK(!end_of_segment_cb.is_null());
  61
  62   ChangeState(kParsingBoxes);
  63   init_cb_ = init_cb;
  64   config_cb_ = config_cb;
  65   new_buffers_cb_ = new_buffers_cb;
  66   encrypted_media_init_data_cb_ = encrypted_media_init_data_cb;
  67   new_segment_cb_ = new_segment_cb;
  68   end_of_segment_cb_ = end_of_segment_cb;
  69   log_cb_ = log_cb;
  70 }
  71
  72 void MP4StreamParser::Reset() {
  73   queue_.Reset();
  74   runs_.reset();
  75   moof_head_ = 0;
  76   mdat_tail_ = 0;
  77 }
  78
  79 void MP4StreamParser::Flush() {
  80   DCHECK_NE(state_, kWaitingForInit);
  81   Reset();
  82   ChangeState(kParsingBoxes);
  83 }
  84
  85 bool MP4StreamParser::Parse(const uint8* buf, int size) {
  86   DCHECK_NE(state_, kWaitingForInit);
  87
  88   if (state_ == kError)
  89     return false;
  90
  91   queue_.Push(buf, size);
  92
  93   BufferQueue audio_buffers;
  94   BufferQueue video_buffers;
  95
  96   bool result = false;
  97   bool err = false;
  98
  99   do {
 100     switch (state_) {
 101       case kWaitingForInit:
 102       case kError:
 103         NOTREACHED();
 104         return false;
 105
 106       case kParsingBoxes:
 107         result = ParseBox(&err);
 108         break;
 109
 110       case kWaitingForSampleData:
 111         result = HaveEnoughDataToEnqueueSamples();
 112         if (result)
 113           ChangeState(kEmittingSamples);
 114         break;
 115
 116       case kEmittingSamples:
 117         result = EnqueueSample(&audio_buffers, &video_buffers, &err);
 118         if (result) {
 119           int64 max_clear = runs_->GetMaxClearOffset() + moof_head_;
 120           err = !ReadAndDiscardMDATsUntil(max_clear);
 121         }
 122         break;
 123     }
 124   } while (result && !err);
 125
 126   if (!err)
 127     err = !SendAndFlushSamples(&audio_buffers, &video_buffers);
 128
 129   if (err) {
 130     DLOG(ERROR) << "Error while parsing MP4";
 131     moov_.reset();
 132     Reset();
 133     ChangeState(kError);
 134     return false;
 135   }
 136
 137   return true;
 138 }
 139
 140 bool MP4StreamParser::ParseBox(bool* err) {
 141   const uint8* buf;
 142   int size;
 143   queue_.Peek(&buf, &size);
 144   if (!size) return false;
 145
 146   scoped_ptr<BoxReader> reader(
 147       BoxReader::ReadTopLevelBox(buf, size, log_cb_, err));
 148   if (reader.get() == NULL) return false;
 149
 150   if (reader->type() == FOURCC_MOOV) {
 151     *err = !ParseMoov(reader.get());
 152   } else if (reader->type() == FOURCC_MOOF) {
 153     moof_head_ = queue_.head();
 154     *err = !ParseMoof(reader.get());
 155
 156     // Set up first mdat offset for ReadMDATsUntil().
 157     mdat_tail_ = queue_.head() + reader->size();
 158
 159     // Return early to avoid evicting 'moof' data from queue. Auxiliary info may
 160     // be located anywhere in the file, including inside the 'moof' itself.
 161     // (Since 'default-base-is-moof' is mandated, no data references can come
 162     // before the head of the 'moof', so keeping this box around is sufficient.)
 163     return !(*err);
 164   } else {
 165     MEDIA_LOG(log_cb_) << "Skipping unrecognized top-level box: "
 166                        << FourCCToString(reader->type());
 167   }
 168
 169   queue_.Pop(reader->size());
 170   return !(*err);
 171 }
 172
 173
 174 bool MP4StreamParser::ParseMoov(BoxReader* reader) {
 175   moov_.reset(new Movie);
 176   RCHECK(moov_->Parse(reader));
 177   runs_.reset();
 178
 179   has_audio_ = false;
 180   has_video_ = false;
 181
 182   AudioDecoderConfig audio_config;
 183   VideoDecoderConfig video_config;
 184
 185   for (std::vector<Track>::const_iterator track = moov_->tracks.begin();
 186        track != moov_->tracks.end(); ++track) {
 187     // TODO(strobe): Only the first audio and video track present in a file are
 188     // used. (Track selection is better accomplished via Source IDs, though, so
 189     // adding support for track selection within a stream is low-priority.)
 190     const SampleDescription& samp_descr =
 191         track->media.information.sample_table.description;
 192
 193     // TODO(strobe): When codec reconfigurations are supported, detect and send
 194     // a codec reconfiguration for fragments using a sample description index
 195     // different from the previous one
 196     size_t desc_idx = 0;
 197     for (size_t t = 0; t < moov_->extends.tracks.size(); t++) {
 198       const TrackExtends& trex = moov_->extends.tracks[t];
 199       if (trex.track_id == track->header.track_id) {
 200         desc_idx = trex.default_sample_description_index;
 201         break;
 202       }
 203     }
 204     RCHECK(desc_idx > 0);
 205     desc_idx -= 1;  // BMFF descriptor index is one-based
 206
 207     if (track->media.handler.type == kAudio && !audio_config.IsValidConfig()) {
 208       RCHECK(!samp_descr.audio_entries.empty());
 209
 210       // It is not uncommon to find otherwise-valid files with incorrect sample
 211       // description indices, so we fail gracefully in that case.
 212       if (desc_idx >= samp_descr.audio_entries.size())
 213         desc_idx = 0;
 214       const AudioSampleEntry& entry = samp_descr.audio_entries[desc_idx];
 215       const AAC& aac = entry.esds.aac;
 216
 217       if (!(entry.format == FOURCC_MP4A ||
 218             (entry.format == FOURCC_ENCA &&
 219              entry.sinf.format.format == FOURCC_MP4A))) {
 220         MEDIA_LOG(log_cb_) << "Unsupported audio format 0x"
 221                            << std::hex << entry.format << " in stsd box.";
 222         return false;
 223       }
 224
 225       uint8 audio_type = entry.esds.object_type;
 226       DVLOG(1) << "audio_type " << std::hex << static_cast<int>(audio_type);
 227       if (audio_object_types_.find(audio_type) == audio_object_types_.end()) {
 228         MEDIA_LOG(log_cb_) << "audio object type 0x" << std::hex << audio_type
 229                            << " does not match what is specified in the"
 230                            << " mimetype.";
 231         return false;
 232       }
 233
 234       AudioCodec codec = kUnknownAudioCodec;
 235       ChannelLayout channel_layout = CHANNEL_LAYOUT_NONE;
 236       int sample_per_second = 0;
 237       std::vector<uint8> extra_data;
 238       // Check if it is MPEG4 AAC defined in ISO 14496 Part 3 or
 239       // supported MPEG2 AAC varients.
 240       if (ESDescriptor::IsAAC(audio_type)) {
 241         codec = kCodecAAC;
 242         channel_layout = aac.GetChannelLayout(has_sbr_);
 243         sample_per_second = aac.GetOutputSamplesPerSecond(has_sbr_);
 244 #if defined(OS_ANDROID)
 245         extra_data = aac.codec_specific_data();
 246 #endif
 247       } else {
 248         MEDIA_LOG(log_cb_) << "Unsupported audio object type 0x" << std::hex
 249                            << audio_type << " in esds.";
 250         return false;
 251       }
 252
 253       SampleFormat sample_format;
 254       if (entry.samplesize == 8) {
 255         sample_format = kSampleFormatU8;
 256       } else if (entry.samplesize == 16) {
 257         sample_format = kSampleFormatS16;
 258       } else if (entry.samplesize == 32) {
 259         sample_format = kSampleFormatS32;
 260       } else {
 261         LOG(ERROR) << "Unsupported sample size.";
 262         return false;
 263       }
 264
 265       is_audio_track_encrypted_ = entry.sinf.info.track_encryption.is_encrypted;
 266       DVLOG(1) << "is_audio_track_encrypted_: " << is_audio_track_encrypted_;
 267       audio_config.Initialize(
 268           codec, sample_format, channel_layout, sample_per_second,
 269           extra_data.size() ? &extra_data[0] : NULL, extra_data.size(),
 270           is_audio_track_encrypted_, false, base::TimeDelta(),
 271           0);
 272       has_audio_ = true;
 273       audio_track_id_ = track->header.track_id;
 274     }
 275     if (track->media.handler.type == kVideo && !video_config.IsValidConfig()) {
 276       RCHECK(!samp_descr.video_entries.empty());
 277       if (desc_idx >= samp_descr.video_entries.size())
 278         desc_idx = 0;
 279       const VideoSampleEntry& entry = samp_descr.video_entries[desc_idx];
 280
 281       if (!entry.IsFormatValid()) {
 282         MEDIA_LOG(log_cb_) << "Unsupported video format 0x"
 283                            << std::hex << entry.format << " in stsd box.";
 284         return false;
 285       }
 286
 287       // TODO(strobe): Recover correct crop box
 288       gfx::Size coded_size(entry.width, entry.height);
 289       gfx::Rect visible_rect(coded_size);
 290       gfx::Size natural_size = GetNaturalSize(visible_rect.size(),
 291                                               entry.pixel_aspect.h_spacing,
 292                                               entry.pixel_aspect.v_spacing);
 293       is_video_track_encrypted_ = entry.sinf.info.track_encryption.is_encrypted;
 294       DVLOG(1) << "is_video_track_encrypted_: " << is_video_track_encrypted_;
 295       video_config.Initialize(kCodecH264, H264PROFILE_MAIN,  VideoFrame::YV12,
 296                               coded_size, visible_rect, natural_size,
 297                               // No decoder-specific buffer needed for AVC;
 298                               // SPS/PPS are embedded in the video stream
 299                               NULL, 0, is_video_track_encrypted_, false);
 300       has_video_ = true;
 301       video_track_id_ = track->header.track_id;
 302     }
 303   }
 304
 305   RCHECK(config_cb_.Run(audio_config, video_config, TextTrackConfigMap()));
 306
 307   StreamParser::InitParameters params(kInfiniteDuration());
 308   if (moov_->extends.header.fragment_duration > 0) {
 309     params.duration = TimeDeltaFromRational(
 310         moov_->extends.header.fragment_duration, moov_->header.timescale);
 311   } else if (moov_->header.duration > 0 &&
 312              moov_->header.duration != kuint64max) {
 313     params.duration =
 314         TimeDeltaFromRational(moov_->header.duration, moov_->header.timescale);
 315   }
 316
 317   if (!init_cb_.is_null())
 318     base::ResetAndReturn(&init_cb_).Run(true, params);
 319
 320   if (!moov_->pssh.empty())
 321     OnEncryptedMediaInitData(moov_->pssh);
 322
 323   return true;
 324 }
 325
 326 bool MP4StreamParser::ParseMoof(BoxReader* reader) {
 327   RCHECK(moov_.get());  // Must already have initialization segment
 328   MovieFragment moof;
 329   RCHECK(moof.Parse(reader));
 330   if (!runs_)
 331     runs_.reset(new TrackRunIterator(moov_.get(), log_cb_));
 332   RCHECK(runs_->Init(moof));
 333   RCHECK(ComputeHighestEndOffset(moof));
 334
 335   if (!moof.pssh.empty())
 336     OnEncryptedMediaInitData(moof.pssh);
 337
 338   new_segment_cb_.Run();
 339   ChangeState(kWaitingForSampleData);
 340   return true;
 341 }
 342
 343 void MP4StreamParser::OnEncryptedMediaInitData(
 344     const std::vector<ProtectionSystemSpecificHeader>& headers) {
 345   // TODO(strobe): ensure that the value of init_data (all PSSH headers
 346   // concatenated in arbitrary order) matches the EME spec.
 347   // See https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673.
 348   size_t total_size = 0;
 349   for (size_t i = 0; i < headers.size(); i++)
 350     total_size += headers[i].raw_box.size();
 351
 352   std::vector<uint8> init_data(total_size);
 353   size_t pos = 0;
 354   for (size_t i = 0; i < headers.size(); i++) {
 355     memcpy(&init_data[pos], &headers[i].raw_box[0],
 356            headers[i].raw_box.size());
 357     pos += headers[i].raw_box.size();
 358   }
 359   encrypted_media_init_data_cb_.Run(kCencInitDataType, init_data);
 360 }
 361
 362 bool MP4StreamParser::PrepareAVCBuffer(
 363     const AVCDecoderConfigurationRecord& avc_config,
 364     std::vector<uint8>* frame_buf,
 365     std::vector<SubsampleEntry>* subsamples) const {
 366   // Convert the AVC NALU length fields to Annex B headers, as expected by
 367   // decoding libraries. Since this may enlarge the size of the buffer, we also
 368   // update the clear byte count for each subsample if encryption is used to
 369   // account for the difference in size between the length prefix and Annex B
 370   // start code.
 371   RCHECK(AVC::ConvertFrameToAnnexB(avc_config.length_size, frame_buf));
 372   if (!subsamples->empty()) {
 373     const int nalu_size_diff = 4 - avc_config.length_size;
 374     size_t expected_size = runs_->sample_size() +
 375         subsamples->size() * nalu_size_diff;
 376     RCHECK(frame_buf->size() == expected_size);
 377     for (size_t i = 0; i < subsamples->size(); i++)
 378       (*subsamples)[i].clear_bytes += nalu_size_diff;
 379   }
 380
 381   if (runs_->is_keyframe()) {
 382     // If this is a keyframe, we (re-)inject SPS and PPS headers at the start of
 383     // a frame. If subsample info is present, we also update the clear byte
 384     // count for that first subsample.
 385     RCHECK(AVC::InsertParamSetsAnnexB(avc_config, frame_buf, subsamples));
 386   }
 387
 388   DCHECK(AVC::IsValidAnnexB(*frame_buf, *subsamples));
 389   return true;
 390 }
 391
 392 bool MP4StreamParser::PrepareAACBuffer(
 393     const AAC& aac_config, std::vector<uint8>* frame_buf,
 394     std::vector<SubsampleEntry>* subsamples) const {
 395   // Append an ADTS header to every audio sample.
 396   RCHECK(aac_config.ConvertEsdsToADTS(frame_buf));
 397
 398   // As above, adjust subsample information to account for the headers. AAC is
 399   // not required to use subsample encryption, so we may need to add an entry.
 400   if (subsamples->empty()) {
 401     subsamples->push_back(SubsampleEntry(
 402         kADTSHeaderMinSize, frame_buf->size() - kADTSHeaderMinSize));
 403   } else {
 404     (*subsamples)[0].clear_bytes += kADTSHeaderMinSize;
 405   }
 406   return true;
 407 }
 408
 409 bool MP4StreamParser::EnqueueSample(BufferQueue* audio_buffers,
 410                                     BufferQueue* video_buffers,
 411                                     bool* err) {
 412   DCHECK_EQ(state_, kEmittingSamples);
 413
 414   if (!runs_->IsRunValid()) {
 415     // Flush any buffers we've gotten in this chunk so that buffers don't
 416     // cross NewSegment() calls
 417     *err = !SendAndFlushSamples(audio_buffers, video_buffers);
 418     if (*err)
 419       return false;
 420
 421     // Remain in kEmittingSamples state, discarding data, until the end of
 422     // the current 'mdat' box has been appended to the queue.
 423     if (!queue_.Trim(mdat_tail_))
 424       return false;
 425
 426     ChangeState(kParsingBoxes);
 427     end_of_segment_cb_.Run();
 428     return true;
 429   }
 430
 431   if (!runs_->IsSampleValid()) {
 432     runs_->AdvanceRun();
 433     return true;
 434   }
 435
 436   DCHECK(!(*err));
 437
 438   const uint8* buf;
 439   int buf_size;
 440   queue_.Peek(&buf, &buf_size);
 441   if (!buf_size) return false;
 442
 443   bool audio = has_audio_ && audio_track_id_ == runs_->track_id();
 444   bool video = has_video_ && video_track_id_ == runs_->track_id();
 445
 446   // Skip this entire track if it's not one we're interested in
 447   if (!audio && !video) {
 448     runs_->AdvanceRun();
 449     return true;
 450   }
 451
 452   // Attempt to cache the auxiliary information first. Aux info is usually
 453   // placed in a contiguous block before the sample data, rather than being
 454   // interleaved. If we didn't cache it, this would require that we retain the
 455   // start of the segment buffer while reading samples. Aux info is typically
 456   // quite small compared to sample data, so this pattern is useful on
 457   // memory-constrained devices where the source buffer consumes a substantial
 458   // portion of the total system memory.
 459   if (runs_->AuxInfoNeedsToBeCached()) {
 460     queue_.PeekAt(runs_->aux_info_offset() + moof_head_, &buf, &buf_size);
 461     if (buf_size < runs_->aux_info_size()) return false;
 462     *err = !runs_->CacheAuxInfo(buf, buf_size);
 463     return !*err;
 464   }
 465
 466   queue_.PeekAt(runs_->sample_offset() + moof_head_, &buf, &buf_size);
 467   if (buf_size < runs_->sample_size()) return false;
 468
 469   scoped_ptr<DecryptConfig> decrypt_config;
 470   std::vector<SubsampleEntry> subsamples;
 471   if (runs_->is_encrypted()) {
 472     decrypt_config = runs_->GetDecryptConfig();
 473     if (!decrypt_config) {
 474       *err = true;
 475       return false;
 476     }
 477     subsamples = decrypt_config->subsamples();
 478   }
 479
 480   std::vector<uint8> frame_buf(buf, buf + runs_->sample_size());
 481   if (video) {
 482     if (!PrepareAVCBuffer(runs_->video_description().avcc,
 483                           &frame_buf, &subsamples)) {
 484       MEDIA_LOG(log_cb_) << "Failed to prepare AVC sample for decode";
 485       *err = true;
 486       return false;
 487     }
 488   }
 489
 490   if (audio) {
 491     if (ESDescriptor::IsAAC(runs_->audio_description().esds.object_type) &&
 492         !PrepareAACBuffer(runs_->audio_description().esds.aac,
 493                           &frame_buf, &subsamples)) {
 494       MEDIA_LOG(log_cb_) << "Failed to prepare AAC sample for decode";
 495       *err = true;
 496       return false;
 497     }
 498   }
 499
 500   if (decrypt_config) {
 501     if (!subsamples.empty()) {
 502     // Create a new config with the updated subsamples.
 503     decrypt_config.reset(new DecryptConfig(
 504         decrypt_config->key_id(),
 505         decrypt_config->iv(),
 506         subsamples));
 507     }
 508     // else, use the existing config.
 509   } else if ((audio && is_audio_track_encrypted_) ||
 510              (video && is_video_track_encrypted_)) {
 511     // The media pipeline requires a DecryptConfig with an empty |iv|.
 512     // TODO(ddorwin): Refactor so we do not need a fake key ID ("1");
 513     decrypt_config.reset(
 514         new DecryptConfig("1", "", std::vector<SubsampleEntry>()));
 515   }
 516
 517   StreamParserBuffer::Type buffer_type = audio ? DemuxerStream::AUDIO :
 518       DemuxerStream::VIDEO;
 519
 520   // TODO(wolenetz/acolwell): Validate and use a common cross-parser TrackId
 521   // type and allow multiple tracks for same media type, if applicable. See
 522   // https://crbug.com/341581.
 523   //
 524   // NOTE: MPEG's "random access point" concept is equivalent to the
 525   // downstream code's "is keyframe" concept.
 526   scoped_refptr<StreamParserBuffer> stream_buf =
 527       StreamParserBuffer::CopyFrom(&frame_buf[0], frame_buf.size(),
 528                                    runs_->is_random_access_point(),
 529                                    buffer_type, 0);
 530
 531   if (decrypt_config)
 532     stream_buf->set_decrypt_config(decrypt_config.Pass());
 533
 534   stream_buf->set_duration(runs_->duration());
 535   stream_buf->set_timestamp(runs_->cts());
 536   stream_buf->SetDecodeTimestamp(runs_->dts());
 537
 538   DVLOG(3) << "Pushing frame: aud=" << audio
 539            << ", key=" << runs_->is_keyframe()
 540            << ", rap=" << runs_->is_random_access_point()
 541            << ", dur=" << runs_->duration().InMilliseconds()
 542            << ", dts=" << runs_->dts().InMilliseconds()
 543            << ", cts=" << runs_->cts().InMilliseconds()
 544            << ", size=" << runs_->sample_size();
 545
 546   if (audio) {
 547     audio_buffers->push_back(stream_buf);
 548   } else {
 549     video_buffers->push_back(stream_buf);
 550   }
 551
 552   runs_->AdvanceSample();
 553   return true;
 554 }
 555
 556 bool MP4StreamParser::SendAndFlushSamples(BufferQueue* audio_buffers,
 557                                           BufferQueue* video_buffers) {
 558   if (audio_buffers->empty() && video_buffers->empty())
 559     return true;
 560
 561   TextBufferQueueMap empty_text_map;
 562   bool success = new_buffers_cb_.Run(*audio_buffers,
 563                                      *video_buffers,
 564                                      empty_text_map);
 565   audio_buffers->clear();
 566   video_buffers->clear();
 567   return success;
 568 }
 569
 570 bool MP4StreamParser::ReadAndDiscardMDATsUntil(int64 max_clear_offset) {
 571   bool err = false;
 572   int64 upper_bound = std::min(max_clear_offset, queue_.tail());
 573   while (mdat_tail_ < upper_bound) {
 574     const uint8* buf = NULL;
 575     int size = 0;
 576     queue_.PeekAt(mdat_tail_, &buf, &size);
 577
 578     FourCC type;
 579     int box_sz;
 580     if (!BoxReader::StartTopLevelBox(buf, size, log_cb_,
 581                                      &type, &box_sz, &err))
 582       break;
 583
 584     if (type != FOURCC_MDAT) {
 585       MEDIA_LOG(log_cb_) << "Unexpected box type while parsing MDATs: "
 586                          << FourCCToString(type);
 587     }
 588     mdat_tail_ += box_sz;
 589   }
 590   queue_.Trim(std::min(mdat_tail_, upper_bound));
 591   return !err;
 592 }
 593
 594 void MP4StreamParser::ChangeState(State new_state) {
 595   DVLOG(2) << "Changing state: " << new_state;
 596   state_ = new_state;
 597 }
 598
 599 bool MP4StreamParser::HaveEnoughDataToEnqueueSamples() {
 600   DCHECK_EQ(state_, kWaitingForSampleData);
 601   // For muxed content, make sure we have data up to |highest_end_offset_|
 602   // so we can ensure proper enqueuing behavior. Otherwise assume we have enough
 603   // data and allow per sample offset checks to meter sample enqueuing.
 604   // TODO(acolwell): Fix trun box handling so we don't have to special case
 605   // muxed content.
 606   return !(has_audio_ && has_video_ &&
 607            queue_.tail() < highest_end_offset_ + moof_head_);
 608 }
 609
 610 bool MP4StreamParser::ComputeHighestEndOffset(const MovieFragment& moof) {
 611   highest_end_offset_ = 0;
 612
 613   TrackRunIterator runs(moov_.get(), log_cb_);
 614   RCHECK(runs.Init(moof));
 615
 616   while (runs.IsRunValid()) {
 617     int64 aux_info_end_offset = runs.aux_info_offset() + runs.aux_info_size();
 618     if (aux_info_end_offset > highest_end_offset_)
 619       highest_end_offset_ = aux_info_end_offset;
 620
 621     while (runs.IsSampleValid()) {
 622       int64 sample_end_offset = runs.sample_offset() + runs.sample_size();
 623       if (sample_end_offset > highest_end_offset_)
 624         highest_end_offset_ = sample_end_offset;
 625
 626       runs.AdvanceSample();
 627     }
 628     runs.AdvanceRun();
 629   }
 630
 631   return true;
 632 }
 633
 634 }  // namespace mp4
 635 }  // namespace media