dom/media/ADTSDemuxer.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef ADTS_DEMUXER_H_
   8 #define ADTS_DEMUXER_H_
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/Maybe.h"
  12 #include "MediaDataDemuxer.h"
  13 #include "MediaResource.h"
  14
  15 namespace mozilla {
  16
  17 namespace adts {
  18 class Frame;
  19 class FrameParser;
  20 }  // namespace adts
  21
  22 class ADTSTrackDemuxer;
  23
  24 DDLoggedTypeDeclNameAndBase(ADTSDemuxer, MediaDataDemuxer);
  25
  26 class ADTSDemuxer : public MediaDataDemuxer,
  27                     public DecoderDoctorLifeLogger<ADTSDemuxer> {
  28  public:
  29   // MediaDataDemuxer interface.
  30   explicit ADTSDemuxer(MediaResource* aSource);
  31   RefPtr<InitPromise> Init() override;
  32   uint32_t GetNumberTracks(TrackInfo::TrackType aType) const override;
  33   already_AddRefed<MediaTrackDemuxer> GetTrackDemuxer(
  34       TrackInfo::TrackType aType, uint32_t aTrackNumber) override;
  35   bool IsSeekable() const override;
  36
  37   // Return true if a valid ADTS frame header could be found.
  38   static bool ADTSSniffer(const uint8_t* aData, const uint32_t aLength);
  39
  40  private:
  41   bool InitInternal();
  42
  43   RefPtr<MediaResource> mSource;
  44   RefPtr<ADTSTrackDemuxer> mTrackDemuxer;
  45 };
  46
  47 DDLoggedTypeNameAndBase(ADTSTrackDemuxer, MediaTrackDemuxer);
  48
  49 class ADTSTrackDemuxer : public MediaTrackDemuxer,
  50                          public DecoderDoctorLifeLogger<ADTSTrackDemuxer> {
  51  public:
  52   explicit ADTSTrackDemuxer(MediaResource* aSource);
  53
  54   // Initializes the track demuxer by reading the first frame for meta data.
  55   // Returns initialization success state.
  56   bool Init();
  57
  58   // Returns the total stream length if known, -1 otherwise.
  59   int64_t StreamLength() const;
  60
  61   // Returns the estimated stream duration, or a 0-duration if unknown.
  62   media::TimeUnit Duration() const;
  63
  64   // Returns the estimated duration up to the given frame number,
  65   // or a 0-duration if unknown.
  66   media::TimeUnit Duration(int64_t aNumFrames) const;
  67
  68   // MediaTrackDemuxer interface.
  69   UniquePtr<TrackInfo> GetInfo() const override;
  70   RefPtr<SeekPromise> Seek(const media::TimeUnit& aTime) override;
  71   RefPtr<SamplesPromise> GetSamples(int32_t aNumSamples = 1) override;
  72   void Reset() override;
  73   RefPtr<SkipAccessPointPromise> SkipToNextRandomAccessPoint(
  74       const media::TimeUnit& aTimeThreshold) override;
  75   int64_t GetResourceOffset() const override;
  76   media::TimeIntervals GetBuffered() override;
  77
  78  private:
  79   // Destructor.
  80   ~ADTSTrackDemuxer();
  81
  82   // Fast approximate seeking to given time.
  83   media::TimeUnit FastSeek(const media::TimeUnit& aTime);
  84
  85   // Seeks by scanning the stream up to the given time for more accurate
  86   // results.
  87   media::TimeUnit ScanUntil(const media::TimeUnit& aTime);
  88
  89   // Finds the next valid frame and returns its byte range.
  90   const adts::Frame& FindNextFrame(bool findFirstFrame = false);
  91
  92   // Skips the next frame given the provided byte range.
  93   bool SkipNextFrame(const adts::Frame& aFrame);
  94
  95   // Returns the next ADTS frame, if available.
  96   already_AddRefed<MediaRawData> GetNextFrame(const adts::Frame& aFrame);
  97
  98   // Updates post-read meta data.
  99   void UpdateState(const adts::Frame& aFrame);
 100
 101   // Returns the frame index for the given offset.
 102   int64_t FrameIndexFromOffset(uint64_t aOffset) const;
 103
 104   // Returns the frame index for the given time.
 105   int64_t FrameIndexFromTime(const media::TimeUnit& aTime) const;
 106
 107   // Reads aSize bytes into aBuffer from the source starting at aOffset.
 108   // Returns the actual size read.
 109   uint32_t Read(uint8_t* aBuffer, int64_t aOffset, int32_t aSize);
 110
 111   // Returns the average frame length derived from the previously parsed frames.
 112   double AverageFrameLength() const;
 113
 114   // The (hopefully) ADTS resource.
 115   MediaResourceIndex mSource;
 116
 117   // ADTS frame parser used to detect frames and extract side info.
 118   adts::FrameParser* mParser;
 119
 120   // Current byte offset in the source stream.
 121   uint64_t mOffset;
 122
 123   // Total parsed frames.
 124   uint64_t mNumParsedFrames;
 125
 126   // Current frame index.
 127   int64_t mFrameIndex;
 128
 129   // Sum of parsed frames' lengths in bytes.
 130   uint64_t mTotalFrameLen;
 131
 132   // Samples per frame metric derived from frame headers or 0 if none available.
 133   uint32_t mSamplesPerFrame;
 134
 135   // Samples per second metric derived from frame headers or 0 if none
 136   // available.
 137   uint32_t mSamplesPerSecond;
 138
 139   // Channel count derived from frame headers or 0 if none available.
 140   uint32_t mChannels;
 141
 142   // Audio track config info.
 143   UniquePtr<AudioInfo> mInfo;
 144
 145   // Amount of pre-roll time when seeking.
 146   // AAC encoder delay is by default 2112 audio frames.
 147   media::TimeUnit mPreRoll;
 148 };
 149
 150 }  // namespace mozilla
 151
 152 #endif  // !ADTS_DEMUXER_H_