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_helpers.h"
   8 #include "base/logging.h"
   9 #include "base/time/time.h"
  10 #include "media/base/audio_decoder_config.h"
  11 #include "media/base/stream_parser_buffer.h"
  12 #include "media/base/text_track_config.h"
  13 #include "media/base/timestamp_constants.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 MP4StreamParser::MP4StreamParser(const std::set<int>& audio_object_types,
  26                                  bool has_sbr)
  27     : state_(kWaitingForInit),
  28       moof_head_(0),
  29       mdat_tail_(0),
  30       highest_end_offset_(0),
  31       has_audio_(false),
  32       has_video_(false),
  33       audio_track_id_(0),
  34       video_track_id_(0),
  35       audio_object_types_(audio_object_types),
  36       has_sbr_(has_sbr),
  37       is_audio_track_encrypted_(false),
  38       is_video_track_encrypted_(false),
  39       num_top_level_box_skipped_(0) {
  40 }
  41
  42 MP4StreamParser::~MP4StreamParser() {}
  43
  44 void MP4StreamParser::Init(
  45     const InitCB& init_cb,
  46     const NewConfigCB& config_cb,
  47     const NewBuffersCB& new_buffers_cb,
  48     bool /* ignore_text_tracks */,
  49     const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
  50     const NewMediaSegmentCB& new_segment_cb,
  51     const base::Closure& end_of_segment_cb,
  52     const scoped_refptr<MediaLog>& media_log) {
  53   DCHECK_EQ(state_, kWaitingForInit);
  54   DCHECK(init_cb_.is_null());
  55   DCHECK(!init_cb.is_null());
  56   DCHECK(!config_cb.is_null());
  57   DCHECK(!new_buffers_cb.is_null());
  58   DCHECK(!encrypted_media_init_data_cb.is_null());
  59   DCHECK(!end_of_segment_cb.is_null());
  60
  61   ChangeState(kParsingBoxes);
  62   init_cb_ = init_cb;
  63   config_cb_ = config_cb;
  64   new_buffers_cb_ = new_buffers_cb;
  65   encrypted_media_init_data_cb_ = encrypted_media_init_data_cb;
  66   new_segment_cb_ = new_segment_cb;
  67   end_of_segment_cb_ = end_of_segment_cb;
  68   media_log_ = media_log;
  69 }
  70
  71 void MP4StreamParser::Reset() {
  72   queue_.Reset();
  73   runs_.reset();
  74   moof_head_ = 0;
  75   mdat_tail_ = 0;
  76 }
  77
  78 void MP4StreamParser::Flush() {
  79   DCHECK_NE(state_, kWaitingForInit);
  80   Reset();
  81   ChangeState(kParsingBoxes);
  82 }
  83
  84 bool MP4StreamParser::Parse(const uint8* buf, int size) {
  85   DCHECK_NE(state_, kWaitingForInit);
  86
  87   if (state_ == kError)
  88     return false;
  89
  90   queue_.Push(buf, size);
  91
  92   BufferQueue audio_buffers;
  93   BufferQueue video_buffers;
  94
  95   bool result = false;
  96   bool err = false;
  97
  98   do {
  99     switch (state_) {
 100       case kWaitingForInit:
 101       case kError:
 102         NOTREACHED();
 103         return false;
 104
 105       case kParsingBoxes:
 106         result = ParseBox(&err);
 107         break;
 108
 109       case kWaitingForSampleData:
 110         result = HaveEnoughDataToEnqueueSamples();
 111         if (result)
 112           ChangeState(kEmittingSamples);
 113         break;
 114
 115       case kEmittingSamples:
 116         result = EnqueueSample(&audio_buffers, &video_buffers, &err);
 117         if (result) {
 118           int64 max_clear = runs_->GetMaxClearOffset() + moof_head_;
 119           err = !ReadAndDiscardMDATsUntil(max_clear);
 120         }
 121         break;
 122     }
 123   } while (result && !err);
 124
 125   if (!err)
 126     err = !SendAndFlushSamples(&audio_buffers, &video_buffers);
 127
 128   if (err) {
 129     DLOG(ERROR) << "Error while parsing MP4";
 130     moov_.reset();
 131     Reset();
 132     ChangeState(kError);
 133     return false;
 134   }
 135
 136   return true;
 137 }
 138
 139 bool MP4StreamParser::ParseBox(bool* err) {
 140   const uint8* buf;
 141   int size;
 142   queue_.Peek(&buf, &size);
 143   if (!size) return false;
 144
 145   scoped_ptr<BoxReader> reader(
 146       BoxReader::ReadTopLevelBox(buf, size, media_log_, err));
 147   if (reader.get() == NULL) return false;
 148
 149   if (reader->type() == FOURCC_MOOV) {
 150     *err = !ParseMoov(reader.get());
 151   } else if (reader->type() == FOURCC_MOOF) {
 152     moof_head_ = queue_.head();
 153     *err = !ParseMoof(reader.get());
 154
 155     // Set up first mdat offset for ReadMDATsUntil().
 156     mdat_tail_ = queue_.head() + reader->size();
 157
 158     // Return early to avoid evicting 'moof' data from queue. Auxiliary info may
 159     // be located anywhere in the file, including inside the 'moof' itself.
 160     // (Since 'default-base-is-moof' is mandated, no data references can come
 161     // before the head of the 'moof', so keeping this box around is sufficient.)
 162     return !(*err);
 163   } else {
 164     // TODO(wolenetz,chcunningham): Enforce more strict adherence to MSE byte
 165     // stream spec for ftyp and styp. See http://crbug.com/504514.
 166     DVLOG(2) << "Skipping unrecognized top-level box: "
 167              << FourCCToString(reader->type());
 168   }
 169
 170   queue_.Pop(reader->size());
 171   return !(*err);
 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(ERROR, media_log_) << "Unsupported audio format 0x"
 221                                      << std::hex << entry.format
 222                                      << " in stsd box.";
 223         return false;
 224       }
 225
 226       uint8 audio_type = entry.esds.object_type;
 227       DVLOG(1) << "audio_type " << std::hex << static_cast<int>(audio_type);
 228       if (audio_object_types_.find(audio_type) == audio_object_types_.end()) {
 229         MEDIA_LOG(ERROR, media_log_)
 230             << "audio object type 0x" << std::hex << audio_type
 231             << " does not match what is specified in the"
 232             << " mimetype.";
 233         return false;
 234       }
 235
 236       AudioCodec codec = kUnknownAudioCodec;
 237       ChannelLayout channel_layout = CHANNEL_LAYOUT_NONE;
 238       int sample_per_second = 0;
 239       std::vector<uint8> extra_data;
 240       // Check if it is MPEG4 AAC defined in ISO 14496 Part 3 or
 241       // supported MPEG2 AAC varients.
 242       if (ESDescriptor::IsAAC(audio_type)) {
 243         codec = kCodecAAC;
 244         channel_layout = aac.GetChannelLayout(has_sbr_);
 245         sample_per_second = aac.GetOutputSamplesPerSecond(has_sbr_);
 246 #if defined(OS_ANDROID)
 247         extra_data = aac.codec_specific_data();
 248 #endif
 249       } else {
 250         MEDIA_LOG(ERROR, media_log_) << "Unsupported audio object type 0x"
 251                                      << std::hex << audio_type << " in esds.";
 252         return false;
 253       }
 254
 255       SampleFormat sample_format;
 256       if (entry.samplesize == 8) {
 257         sample_format = kSampleFormatU8;
 258       } else if (entry.samplesize == 16) {
 259         sample_format = kSampleFormatS16;
 260       } else if (entry.samplesize == 32) {
 261         sample_format = kSampleFormatS32;
 262       } else {
 263         LOG(ERROR) << "Unsupported sample size.";
 264         return false;
 265       }
 266
 267       is_audio_track_encrypted_ = entry.sinf.info.track_encryption.is_encrypted;
 268       DVLOG(1) << "is_audio_track_encrypted_: " << is_audio_track_encrypted_;
 269       audio_config.Initialize(
 270           codec, sample_format, channel_layout, sample_per_second,
 271           extra_data.size() ? &extra_data[0] : NULL, extra_data.size(),
 272           is_audio_track_encrypted_, base::TimeDelta(), 0);
 273       has_audio_ = true;
 274       audio_track_id_ = track->header.track_id;
 275     }
 276     if (track->media.handler.type == kVideo && !video_config.IsValidConfig()) {
 277       RCHECK(!samp_descr.video_entries.empty());
 278       if (desc_idx >= samp_descr.video_entries.size())
 279         desc_idx = 0;
 280       const VideoSampleEntry& entry = samp_descr.video_entries[desc_idx];
 281
 282       if (!entry.IsFormatValid()) {
 283         MEDIA_LOG(ERROR, media_log_) << "Unsupported video format 0x"
 284                                      << std::hex << entry.format
 285                                      << " in stsd box.";
 286         return false;
 287       }
 288
 289       // TODO(strobe): Recover correct crop box
 290       gfx::Size coded_size(entry.width, entry.height);
 291       gfx::Rect visible_rect(coded_size);
 292
 293       // If PASP is available, use the coded size and PASP to calculate the
 294       // natural size. Otherwise, use the size in track header for natural size.
 295       gfx::Size natural_size(visible_rect.size());
 296       if (entry.pixel_aspect.h_spacing != 1 ||
 297           entry.pixel_aspect.v_spacing != 1) {
 298         natural_size =
 299             GetNaturalSize(visible_rect.size(), entry.pixel_aspect.h_spacing,
 300                            entry.pixel_aspect.v_spacing);
 301       } else if (track->header.width && track->header.height) {
 302         natural_size =
 303             gfx::Size(track->header.width, track->header.height);
 304       }
 305
 306       is_video_track_encrypted_ = entry.sinf.info.track_encryption.is_encrypted;
 307       DVLOG(1) << "is_video_track_encrypted_: " << is_video_track_encrypted_;
 308       video_config.Initialize(entry.video_codec, entry.video_codec_profile,
 309                               PIXEL_FORMAT_YV12, COLOR_SPACE_HD_REC709,
 310                               coded_size, visible_rect, natural_size,
 311                               // No decoder-specific buffer needed for AVC;
 312                               // SPS/PPS are embedded in the video stream
 313                               NULL, 0, is_video_track_encrypted_);
 314       has_video_ = true;
 315       video_track_id_ = track->header.track_id;
 316     }
 317   }
 318
 319   RCHECK(config_cb_.Run(audio_config, video_config, TextTrackConfigMap()));
 320
 321   StreamParser::InitParameters params(kInfiniteDuration());
 322   if (moov_->extends.header.fragment_duration > 0) {
 323     params.duration = TimeDeltaFromRational(
 324         moov_->extends.header.fragment_duration, moov_->header.timescale);
 325     params.liveness = DemuxerStream::LIVENESS_RECORDED;
 326   } else if (moov_->header.duration > 0 &&
 327              moov_->header.duration != kuint64max) {
 328     params.duration =
 329         TimeDeltaFromRational(moov_->header.duration, moov_->header.timescale);
 330     params.liveness = DemuxerStream::LIVENESS_RECORDED;
 331   } else {
 332     // In ISO/IEC 14496-12:2005(E), 8.30.2: ".. If an MP4 file is created in
 333     // real-time, such as used in live streaming, it is not likely that the
 334     // fragment_duration is known in advance and this (mehd) box may be
 335     // omitted."
 336     // TODO(wolenetz): Investigate gating liveness detection on timeline_offset
 337     // when it's populated. See http://crbug.com/312699
 338     params.liveness = DemuxerStream::LIVENESS_LIVE;
 339   }
 340
 341   DVLOG(1) << "liveness: " << params.liveness;
 342
 343   if (!init_cb_.is_null())
 344     base::ResetAndReturn(&init_cb_).Run(params);
 345
 346   if (!moov_->pssh.empty())
 347     OnEncryptedMediaInitData(moov_->pssh);
 348
 349   return true;
 350 }
 351
 352 bool MP4StreamParser::ParseMoof(BoxReader* reader) {
 353   RCHECK(moov_.get());  // Must already have initialization segment
 354   MovieFragment moof;
 355   RCHECK(moof.Parse(reader));
 356   if (!runs_)
 357     runs_.reset(new TrackRunIterator(moov_.get(), media_log_));
 358   RCHECK(runs_->Init(moof));
 359   RCHECK(ComputeHighestEndOffset(moof));
 360
 361   if (!moof.pssh.empty())
 362     OnEncryptedMediaInitData(moof.pssh);
 363
 364   new_segment_cb_.Run();
 365   ChangeState(kWaitingForSampleData);
 366   return true;
 367 }
 368
 369 void MP4StreamParser::OnEncryptedMediaInitData(
 370     const std::vector<ProtectionSystemSpecificHeader>& headers) {
 371   // TODO(strobe): ensure that the value of init_data (all PSSH headers
 372   // concatenated in arbitrary order) matches the EME spec.
 373   // See https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673.
 374   size_t total_size = 0;
 375   for (size_t i = 0; i < headers.size(); i++)
 376     total_size += headers[i].raw_box.size();
 377
 378   std::vector<uint8> init_data(total_size);
 379   size_t pos = 0;
 380   for (size_t i = 0; i < headers.size(); i++) {
 381     memcpy(&init_data[pos], &headers[i].raw_box[0],
 382            headers[i].raw_box.size());
 383     pos += headers[i].raw_box.size();
 384   }
 385   encrypted_media_init_data_cb_.Run(EmeInitDataType::CENC, init_data);
 386 }
 387
 388 bool MP4StreamParser::PrepareAACBuffer(
 389     const AAC& aac_config, std::vector<uint8>* frame_buf,
 390     std::vector<SubsampleEntry>* subsamples) const {
 391   // Append an ADTS header to every audio sample.
 392   RCHECK(aac_config.ConvertEsdsToADTS(frame_buf));
 393
 394   // As above, adjust subsample information to account for the headers. AAC is
 395   // not required to use subsample encryption, so we may need to add an entry.
 396   if (subsamples->empty()) {
 397     subsamples->push_back(SubsampleEntry(
 398         kADTSHeaderMinSize, frame_buf->size() - kADTSHeaderMinSize));
 399   } else {
 400     (*subsamples)[0].clear_bytes += kADTSHeaderMinSize;
 401   }
 402   return true;
 403 }
 404
 405 bool MP4StreamParser::EnqueueSample(BufferQueue* audio_buffers,
 406                                     BufferQueue* video_buffers,
 407                                     bool* err) {
 408   DCHECK_EQ(state_, kEmittingSamples);
 409
 410   if (!runs_->IsRunValid()) {
 411     // Flush any buffers we've gotten in this chunk so that buffers don't
 412     // cross NewSegment() calls
 413     *err = !SendAndFlushSamples(audio_buffers, video_buffers);
 414     if (*err)
 415       return false;
 416
 417     // Remain in kEmittingSamples state, discarding data, until the end of
 418     // the current 'mdat' box has been appended to the queue.
 419     if (!queue_.Trim(mdat_tail_))
 420       return false;
 421
 422     ChangeState(kParsingBoxes);
 423     end_of_segment_cb_.Run();
 424     return true;
 425   }
 426
 427   if (!runs_->IsSampleValid()) {
 428     runs_->AdvanceRun();
 429     return true;
 430   }
 431
 432   DCHECK(!(*err));
 433
 434   const uint8* buf;
 435   int buf_size;
 436   queue_.Peek(&buf, &buf_size);
 437   if (!buf_size) return false;
 438
 439   bool audio = has_audio_ && audio_track_id_ == runs_->track_id();
 440   bool video = has_video_ && video_track_id_ == runs_->track_id();
 441
 442   // Skip this entire track if it's not one we're interested in
 443   if (!audio && !video) {
 444     runs_->AdvanceRun();
 445     return true;
 446   }
 447
 448   // Attempt to cache the auxiliary information first. Aux info is usually
 449   // placed in a contiguous block before the sample data, rather than being
 450   // interleaved. If we didn't cache it, this would require that we retain the
 451   // start of the segment buffer while reading samples. Aux info is typically
 452   // quite small compared to sample data, so this pattern is useful on
 453   // memory-constrained devices where the source buffer consumes a substantial
 454   // portion of the total system memory.
 455   if (runs_->AuxInfoNeedsToBeCached()) {
 456     queue_.PeekAt(runs_->aux_info_offset() + moof_head_, &buf, &buf_size);
 457     if (buf_size < runs_->aux_info_size()) return false;
 458     *err = !runs_->CacheAuxInfo(buf, buf_size);
 459     return !*err;
 460   }
 461
 462   queue_.PeekAt(runs_->sample_offset() + moof_head_, &buf, &buf_size);
 463   if (buf_size < runs_->sample_size()) return false;
 464
 465   scoped_ptr<DecryptConfig> decrypt_config;
 466   std::vector<SubsampleEntry> subsamples;
 467   if (runs_->is_encrypted()) {
 468     decrypt_config = runs_->GetDecryptConfig();
 469     if (!decrypt_config) {
 470       *err = true;
 471       return false;
 472     }
 473     subsamples = decrypt_config->subsamples();
 474   }
 475
 476   std::vector<uint8> frame_buf(buf, buf + runs_->sample_size());
 477   if (video) {
 478     DCHECK(runs_->video_description().frame_bitstream_converter);
 479     if (!runs_->video_description().frame_bitstream_converter->ConvertFrame(
 480         &frame_buf, runs_->is_keyframe(), &subsamples)) {
 481       MEDIA_LOG(ERROR, media_log_)
 482           << "Failed to prepare video sample for decode";
 483       *err = true;
 484       return false;
 485     }
 486   }
 487
 488   if (audio) {
 489     if (ESDescriptor::IsAAC(runs_->audio_description().esds.object_type) &&
 490         !PrepareAACBuffer(runs_->audio_description().esds.aac,
 491                           &frame_buf, &subsamples)) {
 492       MEDIA_LOG(ERROR, media_log_) << "Failed to prepare AAC sample for decode";
 493       *err = true;
 494       return false;
 495     }
 496   }
 497
 498   if (decrypt_config) {
 499     if (!subsamples.empty()) {
 500     // Create a new config with the updated subsamples.
 501     decrypt_config.reset(new DecryptConfig(
 502         decrypt_config->key_id(),
 503         decrypt_config->iv(),
 504         subsamples));
 505     }
 506     // else, use the existing config.
 507   } else if ((audio && is_audio_track_encrypted_) ||
 508              (video && is_video_track_encrypted_)) {
 509     // The media pipeline requires a DecryptConfig with an empty |iv|.
 510     // TODO(ddorwin): Refactor so we do not need a fake key ID ("1");
 511     decrypt_config.reset(
 512         new DecryptConfig("1", "", std::vector<SubsampleEntry>()));
 513   }
 514
 515   StreamParserBuffer::Type buffer_type = audio ? DemuxerStream::AUDIO :
 516       DemuxerStream::VIDEO;
 517
 518   // TODO(wolenetz/acolwell): Validate and use a common cross-parser TrackId
 519   // type and allow multiple tracks for same media type, if applicable. See
 520   // https://crbug.com/341581.
 521   scoped_refptr<StreamParserBuffer> stream_buf =
 522       StreamParserBuffer::CopyFrom(&frame_buf[0], frame_buf.size(),
 523                                    runs_->is_keyframe(),
 524                                    buffer_type, 0);
 525
 526   if (decrypt_config)
 527     stream_buf->set_decrypt_config(decrypt_config.Pass());
 528
 529   stream_buf->set_duration(runs_->duration());
 530   stream_buf->set_timestamp(runs_->cts());
 531   stream_buf->SetDecodeTimestamp(runs_->dts());
 532
 533   DVLOG(3) << "Pushing frame: aud=" << audio
 534            << ", key=" << runs_->is_keyframe()
 535            << ", dur=" << runs_->duration().InMilliseconds()
 536            << ", dts=" << runs_->dts().InMilliseconds()
 537            << ", cts=" << runs_->cts().InMilliseconds()
 538            << ", size=" << runs_->sample_size();
 539
 540   if (audio) {
 541     audio_buffers->push_back(stream_buf);
 542   } else {
 543     video_buffers->push_back(stream_buf);
 544   }
 545
 546   runs_->AdvanceSample();
 547   return true;
 548 }
 549
 550 bool MP4StreamParser::SendAndFlushSamples(BufferQueue* audio_buffers,
 551                                           BufferQueue* video_buffers) {
 552   if (audio_buffers->empty() && video_buffers->empty())
 553     return true;
 554
 555   TextBufferQueueMap empty_text_map;
 556   bool success = new_buffers_cb_.Run(*audio_buffers,
 557                                      *video_buffers,
 558                                      empty_text_map);
 559   audio_buffers->clear();
 560   video_buffers->clear();
 561   return success;
 562 }
 563
 564 bool MP4StreamParser::ReadAndDiscardMDATsUntil(int64 max_clear_offset) {
 565   bool err = false;
 566   int64 upper_bound = std::min(max_clear_offset, queue_.tail());
 567   while (mdat_tail_ < upper_bound) {
 568     const uint8* buf = NULL;
 569     int size = 0;
 570     queue_.PeekAt(mdat_tail_, &buf, &size);
 571
 572     FourCC type;
 573     int box_sz;
 574     if (!BoxReader::StartTopLevelBox(buf, size, media_log_, &type, &box_sz,
 575                                      &err))
 576       break;
 577
 578     if (type != FOURCC_MDAT) {
 579       MEDIA_LOG(DEBUG, media_log_)
 580           << "Unexpected box type while parsing MDATs: "
 581           << FourCCToString(type);
 582     }
 583     mdat_tail_ += box_sz;
 584   }
 585   queue_.Trim(std::min(mdat_tail_, upper_bound));
 586   return !err;
 587 }
 588
 589 void MP4StreamParser::ChangeState(State new_state) {
 590   DVLOG(2) << "Changing state: " << new_state;
 591   state_ = new_state;
 592 }
 593
 594 bool MP4StreamParser::HaveEnoughDataToEnqueueSamples() {
 595   DCHECK_EQ(state_, kWaitingForSampleData);
 596   // For muxed content, make sure we have data up to |highest_end_offset_|
 597   // so we can ensure proper enqueuing behavior. Otherwise assume we have enough
 598   // data and allow per sample offset checks to meter sample enqueuing.
 599   // TODO(acolwell): Fix trun box handling so we don't have to special case
 600   // muxed content.
 601   return !(has_audio_ && has_video_ &&
 602            queue_.tail() < highest_end_offset_ + moof_head_);
 603 }
 604
 605 bool MP4StreamParser::ComputeHighestEndOffset(const MovieFragment& moof) {
 606   highest_end_offset_ = 0;
 607
 608   TrackRunIterator runs(moov_.get(), media_log_);
 609   RCHECK(runs.Init(moof));
 610
 611   while (runs.IsRunValid()) {
 612     int64 aux_info_end_offset = runs.aux_info_offset() + runs.aux_info_size();
 613     if (aux_info_end_offset > highest_end_offset_)
 614       highest_end_offset_ = aux_info_end_offset;
 615
 616     while (runs.IsSampleValid()) {
 617       int64 sample_end_offset = runs.sample_offset() + runs.sample_size();
 618       if (sample_end_offset > highest_end_offset_)
 619         highest_end_offset_ = sample_end_offset;
 620
 621       runs.AdvanceSample();
 622     }
 623     runs.AdvanceRun();
 624   }
 625
 626   return true;
 627 }
 628
 629 }  // namespace mp4
 630 }  // namespace media