1 files changed, 673 insertions, 0 deletions

diff --git a/dom/media/MediaInfo.h b/dom/media/MediaInfo.h
new file mode 100644
index 0000000000..c692b94d64
--- /dev/null
+++ b/dom/media/MediaInfo.h
@@ -0,0 +1,673 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#if !defined(MediaInfo_h)
+#  define MediaInfo_h
+
+#  include "mozilla/UniquePtr.h"
+#  include "mozilla/RefPtr.h"
+#  include "mozilla/Variant.h"
+#  include "nsTHashMap.h"
+#  include "nsString.h"
+#  include "nsTArray.h"
+#  include "AudioConfig.h"
+#  include "ImageTypes.h"
+#  include "MediaData.h"
+#  include "TimeUnits.h"
+#  include "mozilla/gfx/Point.h"  // for gfx::IntSize
+#  include "mozilla/gfx/Rect.h"   // for gfx::IntRect
+#  include "mozilla/gfx/Types.h"  // for gfx::ColorDepth
+
+namespace mozilla {
+
+class AudioInfo;
+class VideoInfo;
+class TextInfo;
+
+class MetadataTag {
+ public:
+  MetadataTag(const nsACString& aKey, const nsACString& aValue)
+      : mKey(aKey), mValue(aValue) {}
+  nsCString mKey;
+  nsCString mValue;
+  bool operator==(const MetadataTag& rhs) const {
+    return mKey == rhs.mKey && mValue == rhs.mValue;
+  }
+};
+
+typedef nsTHashMap<nsCStringHashKey, nsCString> MetadataTags;
+
+// Start codec specific data structs. If modifying these remember to also
+// modify the MediaIPCUtils so that any new members are sent across IPC.
+
+// Generic types, we should prefer a specific type when we can.
+
+// Generic empty type. Prefer to use a specific type but not populate members
+// if possible, as that helps with type checking.
+struct NoCodecSpecificData {
+  bool operator==(const NoCodecSpecificData& rhs) const { return true; }
+};
+
+// Generic binary blob type. Prefer not to use this structure. It's here to ease
+// the transition to codec specific structures in the code.
+struct AudioCodecSpecificBinaryBlob {
+  bool operator==(const AudioCodecSpecificBinaryBlob& rhs) const {
+    return *mBinaryBlob == *rhs.mBinaryBlob;
+  }
+
+  RefPtr<MediaByteBuffer> mBinaryBlob{new MediaByteBuffer};
+};
+
+// End generic types.
+
+// Audio codec specific data types.
+
+struct AacCodecSpecificData {
+  bool operator==(const AacCodecSpecificData& rhs) const {
+    return *mEsDescriptorBinaryBlob == *rhs.mEsDescriptorBinaryBlob &&
+           *mDecoderConfigDescriptorBinaryBlob ==
+               *rhs.mDecoderConfigDescriptorBinaryBlob;
+  }
+  // An explanation for the necessity of handling the encoder delay and the
+  // padding is available here:
+  // https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/QTFFAppenG/QTFFAppenG.html
+
+  // The number of frames that should be skipped from the beginning of the
+  // decoded stream.
+  uint32_t mEncoderDelayFrames{0};
+
+  // The total number of frames of the media, that is, excluding the encoder
+  // delay and the padding of the last packet, that must be discarded.
+  uint64_t mMediaFrameCount{0};
+
+  // The bytes of the ES_Descriptor field parsed out of esds box. We store
+  // this as a blob as some decoders want this.
+  RefPtr<MediaByteBuffer> mEsDescriptorBinaryBlob{new MediaByteBuffer};
+
+  // The bytes of the DecoderConfigDescriptor field within the parsed
+  // ES_Descriptor. This is a subset of the ES_Descriptor, so it is technically
+  // redundant to store both. However, some decoders expect this binary blob
+  // instead of the whole ES_Descriptor, so both are stored for convenience
+  // and clarity (rather than reparsing the ES_Descriptor).
+  // TODO(bug 1768562): use a Span to track this rather than duplicating data.
+  RefPtr<MediaByteBuffer> mDecoderConfigDescriptorBinaryBlob{
+      new MediaByteBuffer};
+};
+
+struct FlacCodecSpecificData {
+  bool operator==(const FlacCodecSpecificData& rhs) const {
+    return *mStreamInfoBinaryBlob == *rhs.mStreamInfoBinaryBlob;
+  }
+
+  // A binary blob of the data from the METADATA_BLOCK_STREAMINFO block
+  // in the flac header.
+  // See https://xiph.org/flac/format.html#metadata_block_streaminfo
+  // Consumers of this data (ffmpeg) take a blob, so we don't parse the data,
+  // just store the blob. For headerless flac files this will be left empty.
+  RefPtr<MediaByteBuffer> mStreamInfoBinaryBlob{new MediaByteBuffer};
+};
+
+struct Mp3CodecSpecificData {
+  bool operator==(const Mp3CodecSpecificData& rhs) const {
+    return mEncoderDelayFrames == rhs.mEncoderDelayFrames &&
+           mEncoderPaddingFrames == rhs.mEncoderPaddingFrames;
+  }
+
+  // The number of frames that should be skipped from the beginning of the
+  // decoded stream.
+  // See https://bugzilla.mozilla.org/show_bug.cgi?id=1566389 for more info.
+  uint32_t mEncoderDelayFrames{0};
+
+  // The number of frames that should be skipped from the end of the decoded
+  // stream.
+  // See https://bugzilla.mozilla.org/show_bug.cgi?id=1566389 for more info.
+  uint32_t mEncoderPaddingFrames{0};
+};
+
+struct OpusCodecSpecificData {
+  bool operator==(const OpusCodecSpecificData& rhs) const {
+    return mContainerCodecDelayMicroSeconds ==
+               rhs.mContainerCodecDelayMicroSeconds &&
+           *mHeadersBinaryBlob == *rhs.mHeadersBinaryBlob;
+  }
+  // The codec delay (aka pre-skip) in microseconds.
+  // See https://tools.ietf.org/html/rfc7845#section-4.2 for more info.
+  // This member should store the codec delay parsed from the container file.
+  // In some cases (such as the ogg container), this information is derived
+  // from the same headers stored in the header blob, making storing this
+  // separately redundant. However, other containers store the delay in
+  // addition to the header blob, in which case we can check this container
+  // delay against the header delay to ensure they're consistent.
+  int64_t mContainerCodecDelayMicroSeconds{-1};
+
+  // A binary blob of opus header data, specifically the Identification Header.
+  // See https://datatracker.ietf.org/doc/html/rfc7845.html#section-5.1
+  RefPtr<MediaByteBuffer> mHeadersBinaryBlob{new MediaByteBuffer};
+};
+
+struct VorbisCodecSpecificData {
+  bool operator==(const VorbisCodecSpecificData& rhs) const {
+    return *mHeadersBinaryBlob == *rhs.mHeadersBinaryBlob;
+  }
+
+  // A binary blob of headers in the 'extradata' format (the format ffmpeg
+  // expects for packing the extradata field). This is also the format some
+  // containers use for storing the data. Specifically, this format consists of
+  // the page_segments field, followed by the segment_table field, followed by
+  // the three Vorbis header packets, respectively the identification header,
+  // the comments header, and the setup header, in that order.
+  // See also https://xiph.org/vorbis/doc/framing.html and
+  // https://xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-610004.2
+  RefPtr<MediaByteBuffer> mHeadersBinaryBlob{new MediaByteBuffer};
+};
+
+struct WaveCodecSpecificData {
+  bool operator==(const WaveCodecSpecificData& rhs) const { return true; }
+  // Intentionally empty. We don't store any wave specific data, but this
+  // variant is useful for type checking.
+};
+
+using AudioCodecSpecificVariant =
+    mozilla::Variant<NoCodecSpecificData, AudioCodecSpecificBinaryBlob,
+                     AacCodecSpecificData, FlacCodecSpecificData,
+                     Mp3CodecSpecificData, OpusCodecSpecificData,
+                     VorbisCodecSpecificData, WaveCodecSpecificData>;
+
+// Returns a binary blob representation of the AudioCodecSpecificVariant. This
+// does not guarantee that a binary representation exists. Will return an empty
+// buffer if no representation exists. Prefer `GetAudioCodecSpecificBlob` which
+// asserts if getting a blob is unexpected for a given codec config.
+inline already_AddRefed<MediaByteBuffer> ForceGetAudioCodecSpecificBlob(
+    const AudioCodecSpecificVariant& v) {
+  return v.match(
+      [](const NoCodecSpecificData&) {
+        return RefPtr<MediaByteBuffer>(new MediaByteBuffer).forget();
+      },
+      [](const AudioCodecSpecificBinaryBlob& binaryBlob) {
+        return RefPtr<MediaByteBuffer>(binaryBlob.mBinaryBlob).forget();
+      },
+      [](const AacCodecSpecificData& aacData) {
+        // We return the mDecoderConfigDescriptor blob here, as it is more
+        // commonly used by decoders at time of writing than the
+        // ES_Descriptor data. However, consumers of this data should
+        // prefer getting one or the other specifically, rather than
+        // calling this.
+        return RefPtr<MediaByteBuffer>(
+                   aacData.mDecoderConfigDescriptorBinaryBlob)
+            .forget();
+      },
+      [](const FlacCodecSpecificData& flacData) {
+        return RefPtr<MediaByteBuffer>(flacData.mStreamInfoBinaryBlob).forget();
+      },
+      [](const Mp3CodecSpecificData&) {
+        return RefPtr<MediaByteBuffer>(new MediaByteBuffer).forget();
+      },
+      [](const OpusCodecSpecificData& opusData) {
+        return RefPtr<MediaByteBuffer>(opusData.mHeadersBinaryBlob).forget();
+      },
+      [](const VorbisCodecSpecificData& vorbisData) {
+        return RefPtr<MediaByteBuffer>(vorbisData.mHeadersBinaryBlob).forget();
+      },
+      [](const WaveCodecSpecificData&) {
+        return RefPtr<MediaByteBuffer>(new MediaByteBuffer).forget();
+      });
+}
+
+// Same as `ForceGetAudioCodecSpecificBlob` but with extra asserts to ensure
+// we're not trying to get a binary blob from codecs where we don't store the
+// information as a blob or where a blob is ambiguous.
+inline already_AddRefed<MediaByteBuffer> GetAudioCodecSpecificBlob(
+    const AudioCodecSpecificVariant& v) {
+  MOZ_ASSERT(!v.is<NoCodecSpecificData>(),
+             "NoCodecSpecificData shouldn't be used as a blob");
+  MOZ_ASSERT(!v.is<AacCodecSpecificData>(),
+             "AacCodecSpecificData has 2 blobs internally, one should "
+             "explicitly be selected");
+  MOZ_ASSERT(!v.is<Mp3CodecSpecificData>(),
+             "Mp3CodecSpecificData shouldn't be used as a blob");
+
+  return ForceGetAudioCodecSpecificBlob(v);
+}
+
+// End audio codec specific data types.
+
+// End codec specific data structs.
+
+class TrackInfo {
+ public:
+  enum TrackType { kUndefinedTrack, kAudioTrack, kVideoTrack, kTextTrack };
+  TrackInfo(TrackType aType, const nsAString& aId, const nsAString& aKind,
+            const nsAString& aLabel, const nsAString& aLanguage, bool aEnabled,
+            uint32_t aTrackId)
+      : mId(aId),
+        mKind(aKind),
+        mLabel(aLabel),
+        mLanguage(aLanguage),
+        mEnabled(aEnabled),
+        mTrackId(aTrackId),
+        mIsRenderedExternally(false),
+        mType(aType) {
+    MOZ_COUNT_CTOR(TrackInfo);
+  }
+
+  // Only used for backward compatibility. Do not use in new code.
+  void Init(const nsAString& aId, const nsAString& aKind,
+            const nsAString& aLabel, const nsAString& aLanguage,
+            bool aEnabled) {
+    mId = aId;
+    mKind = aKind;
+    mLabel = aLabel;
+    mLanguage = aLanguage;
+    mEnabled = aEnabled;
+  }
+
+  // Fields common with MediaTrack object.
+  nsString mId;
+  nsString mKind;
+  nsString mLabel;
+  nsString mLanguage;
+  bool mEnabled;
+
+  uint32_t mTrackId;
+
+  nsCString mMimeType;
+  media::TimeUnit mDuration;
+  media::TimeUnit mMediaTime;
+  uint32_t mTimeScale = 0;
+  CryptoTrack mCrypto;
+
+  CopyableTArray<MetadataTag> mTags;
+
+  // True if the track is gonna be (decrypted)/decoded and
+  // rendered directly by non-gecko components.
+  bool mIsRenderedExternally;
+
+  virtual AudioInfo* GetAsAudioInfo() { return nullptr; }
+  virtual VideoInfo* GetAsVideoInfo() { return nullptr; }
+  virtual TextInfo* GetAsTextInfo() { return nullptr; }
+  virtual const AudioInfo* GetAsAudioInfo() const { return nullptr; }
+  virtual const VideoInfo* GetAsVideoInfo() const { return nullptr; }
+  virtual const TextInfo* GetAsTextInfo() const { return nullptr; }
+
+  bool IsAudio() const { return !!GetAsAudioInfo(); }
+  bool IsVideo() const { return !!GetAsVideoInfo(); }
+  bool IsText() const { return !!GetAsTextInfo(); }
+  TrackType GetType() const { return mType; }
+
+  bool virtual IsValid() const = 0;
+
+  virtual UniquePtr<TrackInfo> Clone() const = 0;
+
+  MOZ_COUNTED_DTOR_VIRTUAL(TrackInfo)
+
+ protected:
+  TrackInfo(const TrackInfo& aOther) {
+    mId = aOther.mId;
+    mKind = aOther.mKind;
+    mLabel = aOther.mLabel;
+    mLanguage = aOther.mLanguage;
+    mEnabled = aOther.mEnabled;
+    mTrackId = aOther.mTrackId;
+    mMimeType = aOther.mMimeType;
+    mDuration = aOther.mDuration;
+    mMediaTime = aOther.mMediaTime;
+    mCrypto = aOther.mCrypto;
+    mIsRenderedExternally = aOther.mIsRenderedExternally;
+    mType = aOther.mType;
+    mTags = aOther.mTags.Clone();
+    MOZ_COUNT_CTOR(TrackInfo);
+  }
+  bool IsEqualTo(const TrackInfo& rhs) const;
+
+ private:
+  TrackType mType;
+};
+
+// String version of track type.
+const char* TrackTypeToStr(TrackInfo::TrackType aTrack);
+
+// Stores info relevant to presenting media frames.
+class VideoInfo : public TrackInfo {
+ public:
+  enum Rotation {
+    kDegree_0 = 0,
+    kDegree_90 = 90,
+    kDegree_180 = 180,
+    kDegree_270 = 270,
+  };
+  VideoInfo() : VideoInfo(-1, -1) {}
+
+  VideoInfo(int32_t aWidth, int32_t aHeight)
+      : VideoInfo(gfx::IntSize(aWidth, aHeight)) {}
+
+  explicit VideoInfo(const gfx::IntSize& aSize)
+      : TrackInfo(kVideoTrack, u"2"_ns, u"main"_ns, u""_ns, u""_ns, true, 2),
+        mDisplay(aSize),
+        mStereoMode(StereoMode::MONO),
+        mImage(aSize),
+        mCodecSpecificConfig(new MediaByteBuffer),
+        mExtraData(new MediaByteBuffer),
+        mRotation(kDegree_0) {}
+
+  VideoInfo(const VideoInfo& aOther) = default;
+
+  bool operator==(const VideoInfo& rhs) const;
+
+  bool IsValid() const override {
+    return mDisplay.width > 0 && mDisplay.height > 0;
+  }
+
+  VideoInfo* GetAsVideoInfo() override { return this; }
+
+  const VideoInfo* GetAsVideoInfo() const override { return this; }
+
+  UniquePtr<TrackInfo> Clone() const override {
+    return MakeUnique<VideoInfo>(*this);
+  }
+
+  void SetAlpha(bool aAlphaPresent) { mAlphaPresent = aAlphaPresent; }
+
+  bool HasAlpha() const { return mAlphaPresent; }
+
+  gfx::IntRect ImageRect() const {
+    if (!mImageRect) {
+      return gfx::IntRect(0, 0, mImage.width, mImage.height);
+    }
+    return *mImageRect;
+  }
+
+  void SetImageRect(const gfx::IntRect& aRect) { mImageRect = Some(aRect); }
+  void ResetImageRect() { mImageRect.reset(); }
+
+  // Returned the crop rectangle scaled to aWidth/aHeight size relative to
+  // mImage size.
+  // If aWidth and aHeight are identical to the original
+  // mImage.width/mImage.height then the scaling ratio will be 1. This is used
+  // for when the frame size is different from what the container reports. This
+  // is legal in WebM, and we will preserve the ratio of the crop rectangle as
+  // it was reported relative to the picture size reported by the container.
+  gfx::IntRect ScaledImageRect(int64_t aWidth, int64_t aHeight) const {
+    if ((aWidth == mImage.width && aHeight == mImage.height) || !mImage.width ||
+        !mImage.height) {
+      return ImageRect();
+    }
+
+    gfx::IntRect imageRect = ImageRect();
+    int64_t w = (aWidth * imageRect.Width()) / mImage.width;
+    int64_t h = (aHeight * imageRect.Height()) / mImage.height;
+    if (!w || !h) {
+      return imageRect;
+    }
+
+    imageRect.x = (imageRect.x * aWidth) / mImage.width;
+    imageRect.y = (imageRect.y * aHeight) / mImage.height;
+    imageRect.SetWidth(w);
+    imageRect.SetHeight(h);
+    return imageRect;
+  }
+
+  Rotation ToSupportedRotation(int32_t aDegree) const {
+    switch (aDegree) {
+      case 90:
+        return kDegree_90;
+      case 180:
+        return kDegree_180;
+      case 270:
+        return kDegree_270;
+      default:
+        NS_WARNING_ASSERTION(aDegree == 0, "Invalid rotation degree, ignored");
+        return kDegree_0;
+    }
+  }
+
+  // Size in pixels at which the video is rendered. This is after it has
+  // been scaled by its aspect ratio.
+  gfx::IntSize mDisplay;
+
+  // Indicates the frame layout for single track stereo videos.
+  StereoMode mStereoMode;
+
+  // Size of the decoded video's image.
+  gfx::IntSize mImage;
+
+  RefPtr<MediaByteBuffer> mCodecSpecificConfig;
+  RefPtr<MediaByteBuffer> mExtraData;
+
+  // Describing how many degrees video frames should be rotated in clock-wise to
+  // get correct view.
+  Rotation mRotation;
+
+  // Should be 8, 10 or 12. Default value is 8.
+  gfx::ColorDepth mColorDepth = gfx::ColorDepth::COLOR_8;
+
+  // Matrix coefficients (if specified by the video) imply a colorspace.
+  Maybe<gfx::YUVColorSpace> mColorSpace;
+
+  // Color primaries are independent from the coefficients.
+  Maybe<gfx::ColorSpace2> mColorPrimaries;
+
+  // Transfer functions get their own member, which may not be strongly
+  // correlated to the colorspace.
+  Maybe<gfx::TransferFunction> mTransferFunction;
+
+  // True indicates no restriction on Y, U, V values (otherwise 16-235 for 8
+  // bits etc)
+  gfx::ColorRange mColorRange = gfx::ColorRange::LIMITED;
+
+  Maybe<int32_t> GetFrameRate() const { return mFrameRate; }
+  void SetFrameRate(int32_t aRate) { mFrameRate = Some(aRate); }
+
+ private:
+  friend struct IPC::ParamTraits<VideoInfo>;
+
+  // mImage may be cropped; currently only used with the WebM container.
+  // If unset, no cropping is to occur.
+  Maybe<gfx::IntRect> mImageRect;
+
+  // Indicates whether or not frames may contain alpha information.
+  bool mAlphaPresent = false;
+
+  Maybe<int32_t> mFrameRate;
+};
+
+class AudioInfo : public TrackInfo {
+ public:
+  AudioInfo()
+      : TrackInfo(kAudioTrack, u"1"_ns, u"main"_ns, u""_ns, u""_ns, true, 1),
+        mRate(0),
+        mChannels(0),
+        mChannelMap(AudioConfig::ChannelLayout::UNKNOWN_MAP),
+        mBitDepth(0),
+        mProfile(0),
+        mExtendedProfile(0) {}
+
+  AudioInfo(const AudioInfo& aOther) = default;
+
+  bool operator==(const AudioInfo& rhs) const;
+
+  static const uint32_t MAX_RATE = 640000;
+  static const uint32_t MAX_CHANNEL_COUNT = 256;
+
+  bool IsValid() const override {
+    return mChannels > 0 && mChannels <= MAX_CHANNEL_COUNT && mRate > 0 &&
+           mRate <= MAX_RATE;
+  }
+
+  AudioInfo* GetAsAudioInfo() override { return this; }
+
+  const AudioInfo* GetAsAudioInfo() const override { return this; }
+
+  UniquePtr<TrackInfo> Clone() const override {
+    return MakeUnique<AudioInfo>(*this);
+  }
+
+  // Sample rate.
+  uint32_t mRate;
+
+  // Number of audio channels.
+  uint32_t mChannels;
+  // The AudioConfig::ChannelLayout map. Channels are ordered as per SMPTE
+  // definition. A value of UNKNOWN_MAP indicates unknown layout.
+  // ChannelMap is an unsigned bitmap compatible with Windows' WAVE and FFmpeg
+  // channel map.
+  AudioConfig::ChannelLayout::ChannelMap mChannelMap;
+
+  // Bits per sample.
+  uint32_t mBitDepth;
+
+  // Codec profile.
+  int8_t mProfile;
+
+  // Extended codec profile.
+  int8_t mExtendedProfile;
+
+  AudioCodecSpecificVariant mCodecSpecificConfig{NoCodecSpecificData{}};
+};
+
+class EncryptionInfo {
+ public:
+  EncryptionInfo() : mEncrypted(false) {}
+
+  struct InitData {
+    template <typename AInitDatas>
+    InitData(const nsAString& aType, AInitDatas&& aInitData)
+        : mType(aType), mInitData(std::forward<AInitDatas>(aInitData)) {}
+
+    // Encryption type to be passed to JS. Usually `cenc'.
+    nsString mType;
+
+    // Encryption data.
+    CopyableTArray<uint8_t> mInitData;
+  };
+  typedef CopyableTArray<InitData> InitDatas;
+
+  // True if the stream has encryption metadata
+  bool IsEncrypted() const { return mEncrypted; }
+
+  void Reset() {
+    mEncrypted = false;
+    mInitDatas.Clear();
+  }
+
+  template <typename AInitDatas>
+  void AddInitData(const nsAString& aType, AInitDatas&& aInitData) {
+    mInitDatas.AppendElement(
+        InitData(aType, std::forward<AInitDatas>(aInitData)));
+    mEncrypted = true;
+  }
+
+  void AddInitData(const EncryptionInfo& aInfo) {
+    mInitDatas.AppendElements(aInfo.mInitDatas);
+    mEncrypted = !!mInitDatas.Length();
+  }
+
+  // One 'InitData' per encrypted buffer.
+  InitDatas mInitDatas;
+
+ private:
+  bool mEncrypted;
+};
+
+class MediaInfo {
+ public:
+  bool HasVideo() const { return mVideo.IsValid(); }
+
+  void EnableVideo() {
+    if (HasVideo()) {
+      return;
+    }
+    // Set dummy values so that HasVideo() will return true;
+    // See VideoInfo::IsValid()
+    mVideo.mDisplay = gfx::IntSize(1, 1);
+  }
+
+  bool HasAudio() const { return mAudio.IsValid(); }
+
+  void EnableAudio() {
+    if (HasAudio()) {
+      return;
+    }
+    // Set dummy values so that HasAudio() will return true;
+    // See AudioInfo::IsValid()
+    mAudio.mChannels = 2;
+    mAudio.mRate = 44100;
+  }
+
+  bool IsEncrypted() const {
+    return (HasAudio() && mAudio.mCrypto.IsEncrypted()) ||
+           (HasVideo() && mVideo.mCrypto.IsEncrypted());
+  }
+
+  bool HasValidMedia() const { return HasVideo() || HasAudio(); }
+
+  // TODO: Store VideoInfo and AudioIndo in arrays to support multi-tracks.
+  VideoInfo mVideo;
+  AudioInfo mAudio;
+
+  // If the metadata includes a duration, we store it here.
+  media::NullableTimeUnit mMetadataDuration;
+
+  // The Ogg reader tries to kinda-sorta compute the duration by seeking to the
+  // end and determining the timestamp of the last frame. This isn't useful as
+  // a duration until we know the start time, so we need to track it separately.
+  media::NullableTimeUnit mUnadjustedMetadataEndTime;
+
+  // True if the media is seekable (i.e. supports random access).
+  bool mMediaSeekable = true;
+
+  // True if the media is only seekable within its buffered ranges.
+  bool mMediaSeekableOnlyInBufferedRanges = false;
+
+  EncryptionInfo mCrypto;
+
+  // The minimum of start times of audio and video tracks.
+  // Use to map the zero time on the media timeline to the first frame.
+  media::TimeUnit mStartTime;
+};
+
+class TrackInfoSharedPtr {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(TrackInfoSharedPtr)
+ public:
+  TrackInfoSharedPtr(const TrackInfo& aOriginal, uint32_t aStreamID)
+      : mInfo(aOriginal.Clone()),
+        mStreamSourceID(aStreamID),
+        mMimeType(mInfo->mMimeType) {}
+
+  uint32_t GetID() const { return mStreamSourceID; }
+
+  operator const TrackInfo*() const { return mInfo.get(); }
+
+  const TrackInfo* operator*() const { return mInfo.get(); }
+
+  const TrackInfo* operator->() const {
+    MOZ_ASSERT(mInfo.get(), "dereferencing a UniquePtr containing nullptr");
+    return mInfo.get();
+  }
+
+  const AudioInfo* GetAsAudioInfo() const {
+    return mInfo ? mInfo->GetAsAudioInfo() : nullptr;
+  }
+
+  const VideoInfo* GetAsVideoInfo() const {
+    return mInfo ? mInfo->GetAsVideoInfo() : nullptr;
+  }
+
+  const TextInfo* GetAsTextInfo() const {
+    return mInfo ? mInfo->GetAsTextInfo() : nullptr;
+  }
+
+ private:
+  ~TrackInfoSharedPtr() = default;
+  UniquePtr<TrackInfo> mInfo;
+  // A unique ID, guaranteed to change when changing streams.
+  uint32_t mStreamSourceID;
+
+ public:
+  const nsCString& mMimeType;
+};
+
+}  // namespace mozilla
+
+#endif  // MediaInfo_h