Add m-esr52 at 52.6.0

1 files changed, 2194 insertions, 0 deletions

diff --git a/dom/media/ogg/OggDemuxer.cpp b/dom/media/ogg/OggDemuxer.cpp
new file mode 100644
index 000000000..591a5248f
--- /dev/null
+++ b/dom/media/ogg/OggDemuxer.cpp
@@ -0,0 +1,2194 @@
+ /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+
+#include "nsError.h"
+#include "MediaDecoderStateMachine.h"
+#include "AbstractMediaDecoder.h"
+#include "OggDemuxer.h"
+#include "OggCodecState.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/PodOperations.h"
+#include "mozilla/SharedThreadPool.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TimeStamp.h"
+#include "MediaDataDemuxer.h"
+#include "nsAutoRef.h"
+#include "XiphExtradata.h"
+#include "MediaPrefs.h"
+
+#include <algorithm>
+
+extern mozilla::LazyLogModule gMediaDemuxerLog;
+#define OGG_DEBUG(arg, ...) MOZ_LOG(gMediaDemuxerLog, mozilla::LogLevel::Debug, ("OggDemuxer(%p)::%s: " arg, this, __func__, ##__VA_ARGS__))
+
+// Un-comment to enable logging of seek bisections.
+//#define SEEK_LOGGING
+#ifdef SEEK_LOGGING
+#define SEEK_LOG(type, msg) MOZ_LOG(gMediaDemuxerLog, type, msg)
+#else
+#define SEEK_LOG(type, msg)
+#endif
+
+namespace mozilla
+{
+
+using media::TimeUnit;
+using media::TimeInterval;
+using media::TimeIntervals;
+
+// The number of microseconds of "fuzz" we use in a bisection search over
+// HTTP. When we're seeking with fuzz, we'll stop the search if a bisection
+// lands between the seek target and OGG_SEEK_FUZZ_USECS microseconds before the
+// seek target.  This is becaue it's usually quicker to just keep downloading
+// from an exisiting connection than to do another bisection inside that
+// small range, which would open a new HTTP connetion.
+static const uint32_t OGG_SEEK_FUZZ_USECS = 500000;
+
+// The number of microseconds of "pre-roll" we use for Opus streams.
+// The specification recommends 80 ms.
+static const int64_t OGG_SEEK_OPUS_PREROLL = 80 * USECS_PER_MS;
+
+static Atomic<uint32_t> sStreamSourceID(0u);
+
+class OggHeaders
+{
+public:
+  OggHeaders() {}
+  ~OggHeaders()
+  {
+    for (size_t i = 0; i < mHeaders.Length(); i++) {
+      delete[] mHeaders[i];
+    }
+  }
+
+  void AppendPacket(const ogg_packet* aPacket)
+  {
+    size_t packetSize = aPacket->bytes;
+    unsigned char* packetData = new unsigned char[packetSize];
+    memcpy(packetData, aPacket->packet, packetSize);
+    mHeaders.AppendElement(packetData);
+    mHeaderLens.AppendElement(packetSize);
+  }
+
+  nsTArray<const unsigned char*> mHeaders;
+  nsTArray<size_t> mHeaderLens;
+};
+
+// Return the corresponding category in aKind based on the following specs.
+// (https://www.whatwg.org/specs/web-apps/current-
+// work/multipage/embedded-content.html#dom-audiotrack-kind) &
+// (http://wiki.xiph.org/SkeletonHeaders)
+const nsString
+OggDemuxer::GetKind(const nsCString& aRole)
+{
+  if (aRole.Find("audio/main") != -1 || aRole.Find("video/main") != -1) {
+    return NS_LITERAL_STRING("main");
+  } else if (aRole.Find("audio/alternate") != -1 ||
+             aRole.Find("video/alternate") != -1) {
+    return NS_LITERAL_STRING("alternative");
+  } else if (aRole.Find("audio/audiodesc") != -1) {
+    return NS_LITERAL_STRING("descriptions");
+  } else if (aRole.Find("audio/described") != -1) {
+    return NS_LITERAL_STRING("main-desc");
+  } else if (aRole.Find("audio/dub") != -1) {
+    return NS_LITERAL_STRING("translation");
+  } else if (aRole.Find("audio/commentary") != -1) {
+    return NS_LITERAL_STRING("commentary");
+  } else if (aRole.Find("video/sign") != -1) {
+    return NS_LITERAL_STRING("sign");
+  } else if (aRole.Find("video/captioned") != -1) {
+    return NS_LITERAL_STRING("captions");
+  } else if (aRole.Find("video/subtitled") != -1) {
+    return NS_LITERAL_STRING("subtitles");
+  }
+  return EmptyString();
+}
+
+void
+OggDemuxer::InitTrack(MessageField* aMsgInfo,
+                      TrackInfo* aInfo,
+                      bool aEnable)
+{
+  MOZ_ASSERT(aMsgInfo);
+  MOZ_ASSERT(aInfo);
+
+  nsCString* sName = aMsgInfo->mValuesStore.Get(eName);
+  nsCString* sRole = aMsgInfo->mValuesStore.Get(eRole);
+  nsCString* sTitle = aMsgInfo->mValuesStore.Get(eTitle);
+  nsCString* sLanguage = aMsgInfo->mValuesStore.Get(eLanguage);
+  aInfo->Init(sName? NS_ConvertUTF8toUTF16(*sName):EmptyString(),
+              sRole? GetKind(*sRole):EmptyString(),
+              sTitle? NS_ConvertUTF8toUTF16(*sTitle):EmptyString(),
+              sLanguage? NS_ConvertUTF8toUTF16(*sLanguage):EmptyString(),
+              aEnable);
+}
+
+OggDemuxer::OggDemuxer(MediaResource* aResource)
+  : mTheoraState(nullptr)
+  , mVorbisState(nullptr)
+  , mOpusState(nullptr)
+  , mFlacState(nullptr)
+  , mOpusEnabled(MediaDecoder::IsOpusEnabled())
+  , mSkeletonState(nullptr)
+  , mAudioOggState(aResource)
+  , mVideoOggState(aResource)
+  , mVorbisSerial(0)
+  , mOpusSerial(0)
+  , mTheoraSerial(0)
+  , mFlacSerial(0)
+  , mOpusPreSkip(0)
+  , mIsChained(false)
+  , mTimedMetadataEvent(nullptr)
+  , mOnSeekableEvent(nullptr)
+{
+  MOZ_COUNT_CTOR(OggDemuxer);
+  PodZero(&mTheoraInfo);
+}
+
+OggDemuxer::~OggDemuxer()
+{
+  MOZ_COUNT_DTOR(OggDemuxer);
+  Reset(TrackInfo::kAudioTrack);
+  Reset(TrackInfo::kVideoTrack);
+  if (HasAudio() || HasVideo()) {
+    // If we were able to initialize our decoders, report whether we encountered
+    // a chained stream or not.
+    bool isChained = mIsChained;
+    void* ptr = this;
+    nsCOMPtr<nsIRunnable> task = NS_NewRunnableFunction([ptr, isChained]() -> void {
+      // We can't use OGG_DEBUG here because it implicitly refers to `this`,
+      // which we can't capture in this runnable.
+      MOZ_LOG(gMediaDemuxerLog, mozilla::LogLevel::Debug,
+              ("OggDemuxer(%p)::%s: Reporting telemetry MEDIA_OGG_LOADED_IS_CHAINED=%d",
+               ptr, __func__, isChained));
+      Telemetry::Accumulate(Telemetry::ID::MEDIA_OGG_LOADED_IS_CHAINED, isChained);
+    });
+    AbstractThread::MainThread()->Dispatch(task.forget());
+  }
+}
+
+void
+OggDemuxer::SetChainingEvents(TimedMetadataEventProducer* aMetadataEvent,
+                              MediaEventProducer<void>* aOnSeekableEvent)
+{
+  mTimedMetadataEvent = aMetadataEvent;
+  mOnSeekableEvent = aOnSeekableEvent;
+}
+
+
+bool
+OggDemuxer::HasAudio()
+const
+{
+  return mVorbisState || mOpusState || mFlacState;
+}
+
+bool
+OggDemuxer::HasVideo()
+const
+{
+  return mTheoraState;
+}
+
+bool
+OggDemuxer::HaveStartTime()
+const
+{
+  return mStartTime.isSome();
+}
+
+int64_t
+OggDemuxer::StartTime() const
+{
+  return mStartTime.refOr(0);
+}
+
+bool
+OggDemuxer::HaveStartTime(TrackInfo::TrackType aType)
+{
+  return OggState(aType).mStartTime.isSome();
+}
+
+int64_t
+OggDemuxer::StartTime(TrackInfo::TrackType aType)
+{
+  return OggState(aType).mStartTime.refOr(TimeUnit::FromMicroseconds(0)).ToMicroseconds();
+}
+
+RefPtr<OggDemuxer::InitPromise>
+OggDemuxer::Init()
+{
+  int ret = ogg_sync_init(OggSyncState(TrackInfo::kAudioTrack));
+  if (ret != 0) {
+    return InitPromise::CreateAndReject(NS_ERROR_OUT_OF_MEMORY, __func__);
+  }
+  ret = ogg_sync_init(OggSyncState(TrackInfo::kVideoTrack));
+  if (ret != 0) {
+    return InitPromise::CreateAndReject(NS_ERROR_OUT_OF_MEMORY, __func__);
+  }
+  if (ReadMetadata() != NS_OK) {
+    return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_METADATA_ERR, __func__);
+  }
+
+  if (!GetNumberTracks(TrackInfo::kAudioTrack) &&
+      !GetNumberTracks(TrackInfo::kVideoTrack)) {
+    return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_METADATA_ERR, __func__);
+  }
+
+  return InitPromise::CreateAndResolve(NS_OK, __func__);
+}
+
+bool
+OggDemuxer::HasTrackType(TrackInfo::TrackType aType) const
+{
+  return !!GetNumberTracks(aType);
+}
+
+OggCodecState*
+OggDemuxer::GetTrackCodecState(TrackInfo::TrackType aType) const
+{
+  switch(aType) {
+    case TrackInfo::kAudioTrack:
+      if (mVorbisState) {
+        return mVorbisState;
+      } else if (mOpusState) {
+        return mOpusState;
+      } else {
+        return mFlacState;
+      }
+    case TrackInfo::kVideoTrack:
+      return mTheoraState;
+    default:
+      return 0;
+  }
+}
+
+TrackInfo::TrackType
+OggDemuxer::GetCodecStateType(OggCodecState* aState) const
+{
+  switch (aState->GetType()) {
+    case OggCodecState::TYPE_THEORA:
+      return TrackInfo::kVideoTrack;
+    case OggCodecState::TYPE_OPUS:
+    case OggCodecState::TYPE_VORBIS:
+    case OggCodecState::TYPE_FLAC:
+      return TrackInfo::kAudioTrack;
+    default:
+      return TrackInfo::kUndefinedTrack;
+  }
+}
+
+uint32_t
+OggDemuxer::GetNumberTracks(TrackInfo::TrackType aType) const
+{
+  switch(aType) {
+    case TrackInfo::kAudioTrack:
+      return HasAudio() ? 1 : 0;
+    case TrackInfo::kVideoTrack:
+      return HasVideo() ? 1 : 0;
+    default:
+      return 0;
+  }
+}
+
+UniquePtr<TrackInfo>
+OggDemuxer::GetTrackInfo(TrackInfo::TrackType aType, size_t aTrackNumber) const
+{
+  switch(aType) {
+    case TrackInfo::kAudioTrack:
+      return mInfo.mAudio.Clone();
+    case TrackInfo::kVideoTrack:
+      return mInfo.mVideo.Clone();
+    default:
+      return nullptr;
+  }
+}
+
+already_AddRefed<MediaTrackDemuxer>
+OggDemuxer::GetTrackDemuxer(TrackInfo::TrackType aType, uint32_t aTrackNumber)
+{
+  if (GetNumberTracks(aType) <= aTrackNumber) {
+    return nullptr;
+  }
+  RefPtr<OggTrackDemuxer> e = new OggTrackDemuxer(this, aType, aTrackNumber);
+  mDemuxers.AppendElement(e);
+
+  return e.forget();
+}
+
+nsresult
+OggDemuxer::Reset(TrackInfo::TrackType aType)
+{
+  // Discard any previously buffered packets/pages.
+  ogg_sync_reset(OggSyncState(aType));
+  OggCodecState* trackState = GetTrackCodecState(aType);
+  if (trackState) {
+    return trackState->Reset();
+  }
+  OggState(aType).mNeedKeyframe = true;
+  return NS_OK;
+}
+
+bool
+OggDemuxer::ReadHeaders(TrackInfo::TrackType aType,
+                        OggCodecState* aState,
+                        OggHeaders& aHeaders)
+{
+  while (!aState->DoneReadingHeaders()) {
+    DemuxUntilPacketAvailable(aType, aState);
+    ogg_packet* packet = aState->PacketOut();
+    if (!packet) {
+      OGG_DEBUG("Ran out of header packets early; deactivating stream %ld", aState->mSerial);
+      aState->Deactivate();
+      return false;
+    }
+
+    // Save a copy of the header packet for the decoder to use later;
+    // OggCodecState::DecodeHeader will free it when processing locally.
+    aHeaders.AppendPacket(packet);
+
+    // Local OggCodecState needs to decode headers in order to process
+    // packet granulepos -> time mappings, etc.
+    if (!aState->DecodeHeader(packet)) {
+      OGG_DEBUG("Failed to decode ogg header packet; deactivating stream %ld", aState->mSerial);
+      aState->Deactivate();
+      return false;
+    }
+  }
+
+  return aState->Init();
+}
+
+void
+OggDemuxer::BuildSerialList(nsTArray<uint32_t>& aTracks)
+{
+  // Obtaining seek index information for currently active bitstreams.
+  if (HasVideo()) {
+    aTracks.AppendElement(mTheoraState->mSerial);
+  }
+  if (HasAudio()) {
+    if (mVorbisState) {
+      aTracks.AppendElement(mVorbisState->mSerial);
+    } else if (mOpusState) {
+      aTracks.AppendElement(mOpusState->mSerial);
+    }
+  }
+}
+
+void
+OggDemuxer::SetupTargetTheora(TheoraState* aTheoraState, OggHeaders& aHeaders)
+{
+  if (mTheoraState) {
+    mTheoraState->Reset();
+  }
+
+  nsIntRect picture = nsIntRect(aTheoraState->mInfo.pic_x,
+                                aTheoraState->mInfo.pic_y,
+                                aTheoraState->mInfo.pic_width,
+                                aTheoraState->mInfo.pic_height);
+
+  nsIntSize displaySize = nsIntSize(aTheoraState->mInfo.pic_width,
+                                    aTheoraState->mInfo.pic_height);
+
+  // Apply the aspect ratio to produce the intrinsic display size we report
+  // to the element.
+  ScaleDisplayByAspectRatio(displaySize, aTheoraState->mPixelAspectRatio);
+
+  nsIntSize frameSize(aTheoraState->mInfo.frame_width,
+                      aTheoraState->mInfo.frame_height);
+  if (IsValidVideoRegion(frameSize, picture, displaySize)) {
+    // Video track's frame sizes will not overflow. Activate the video track.
+    mInfo.mVideo.mMimeType = "video/theora";
+    mInfo.mVideo.mDisplay = displaySize;
+    mInfo.mVideo.mImage = frameSize;
+    mInfo.mVideo.SetImageRect(picture);
+
+    // Copy Theora info data for time computations on other threads.
+    memcpy(&mTheoraInfo, &aTheoraState->mInfo, sizeof(mTheoraInfo));
+
+    // Save header packets for the decoder
+    if (!XiphHeadersToExtradata(mInfo.mVideo.mCodecSpecificConfig,
+                                aHeaders.mHeaders, aHeaders.mHeaderLens)) {
+      return;
+    }
+
+    mTheoraState = aTheoraState;
+    mTheoraSerial = aTheoraState->mSerial;
+  }
+}
+
+void
+OggDemuxer::SetupTargetVorbis(VorbisState* aVorbisState, OggHeaders& aHeaders)
+{
+  if (mVorbisState) {
+    mVorbisState->Reset();
+  }
+
+  // Copy Vorbis info data for time computations on other threads.
+  memcpy(&mVorbisInfo, &aVorbisState->mInfo, sizeof(mVorbisInfo));
+  mVorbisInfo.codec_setup = nullptr;
+
+  mInfo.mAudio.mMimeType = "audio/vorbis";
+  mInfo.mAudio.mRate = aVorbisState->mInfo.rate;
+  mInfo.mAudio.mChannels = aVorbisState->mInfo.channels;
+
+  // Save header packets for the decoder
+  if (!XiphHeadersToExtradata(mInfo.mAudio.mCodecSpecificConfig,
+                              aHeaders.mHeaders, aHeaders.mHeaderLens)) {
+    return;
+  }
+
+  mVorbisState = aVorbisState;
+  mVorbisSerial = aVorbisState->mSerial;
+}
+
+void
+OggDemuxer::SetupTargetOpus(OpusState* aOpusState, OggHeaders& aHeaders)
+{
+  if (mOpusState) {
+    mOpusState->Reset();
+  }
+
+  mInfo.mAudio.mMimeType = "audio/opus";
+  mInfo.mAudio.mRate = aOpusState->mRate;
+  mInfo.mAudio.mChannels = aOpusState->mChannels;
+
+  // Save preskip & the first header packet for the Opus decoder
+  uint64_t preSkip = aOpusState->Time(0, aOpusState->mPreSkip);
+  uint8_t c[sizeof(preSkip)];
+  BigEndian::writeUint64(&c[0], preSkip);
+  mInfo.mAudio.mCodecSpecificConfig->AppendElements(&c[0], sizeof(preSkip));
+  mInfo.mAudio.mCodecSpecificConfig->AppendElements(aHeaders.mHeaders[0],
+                                                    aHeaders.mHeaderLens[0]);
+
+  mOpusState = aOpusState;
+  mOpusSerial = aOpusState->mSerial;
+  mOpusPreSkip = aOpusState->mPreSkip;
+}
+
+void
+OggDemuxer::SetupTargetFlac(FlacState* aFlacState, OggHeaders& aHeaders)
+{
+  if (mFlacState) {
+    mFlacState->Reset();
+  }
+
+  mInfo.mAudio = aFlacState->Info();
+  mFlacState = aFlacState;
+  mFlacSerial = aFlacState->mSerial;
+}
+
+void
+OggDemuxer::SetupTargetSkeleton()
+{
+  // Setup skeleton related information after mVorbisState & mTheroState
+  // being set (if they exist).
+  if (mSkeletonState) {
+    OggHeaders headers;
+    if (!HasAudio() && !HasVideo()) {
+      // We have a skeleton track, but no audio or video, may as well disable
+      // the skeleton, we can't do anything useful with this media.
+      OGG_DEBUG("Deactivating skeleton stream %ld", mSkeletonState->mSerial);
+      mSkeletonState->Deactivate();
+    } else if (ReadHeaders(TrackInfo::kAudioTrack, mSkeletonState, headers) &&
+               mSkeletonState->HasIndex()) {
+      // We don't particularly care about which track we are currently using
+      // as both MediaResource points to the same content.
+      // Extract the duration info out of the index, so we don't need to seek to
+      // the end of resource to get it.
+      nsTArray<uint32_t> tracks;
+      BuildSerialList(tracks);
+      int64_t duration = 0;
+      if (NS_SUCCEEDED(mSkeletonState->GetDuration(tracks, duration))) {
+        OGG_DEBUG("Got duration from Skeleton index %lld", duration);
+        mInfo.mMetadataDuration.emplace(TimeUnit::FromMicroseconds(duration));
+      }
+    }
+  }
+}
+
+void
+OggDemuxer::SetupMediaTracksInfo(const nsTArray<uint32_t>& aSerials)
+{
+  // For each serial number
+  // 1. Retrieve a codecState from mCodecStore by this serial number.
+  // 2. Retrieve a message field from mMsgFieldStore by this serial number.
+  // 3. For now, skip if the serial number refers to a non-primary bitstream.
+  // 4. Setup track and other audio/video related information per different types.
+  for (size_t i = 0; i < aSerials.Length(); i++) {
+    uint32_t serial = aSerials[i];
+    OggCodecState* codecState = mCodecStore.Get(serial);
+
+    MessageField* msgInfo = nullptr;
+    if (mSkeletonState && mSkeletonState->mMsgFieldStore.Contains(serial)) {
+      mSkeletonState->mMsgFieldStore.Get(serial, &msgInfo);
+    }
+
+    if (codecState->GetType() == OggCodecState::TYPE_THEORA) {
+      TheoraState* theoraState = static_cast<TheoraState*>(codecState);
+      if (!(mTheoraState && mTheoraState->mSerial == theoraState->mSerial)) {
+        continue;
+      }
+
+      if (msgInfo) {
+        InitTrack(msgInfo, &mInfo.mVideo, mTheoraState == theoraState);
+      }
+
+      nsIntRect picture = nsIntRect(theoraState->mInfo.pic_x,
+                                    theoraState->mInfo.pic_y,
+                                    theoraState->mInfo.pic_width,
+                                    theoraState->mInfo.pic_height);
+      nsIntSize displaySize = nsIntSize(theoraState->mInfo.pic_width,
+                                        theoraState->mInfo.pic_height);
+      nsIntSize frameSize(theoraState->mInfo.frame_width,
+                          theoraState->mInfo.frame_height);
+      ScaleDisplayByAspectRatio(displaySize, theoraState->mPixelAspectRatio);
+      if (IsValidVideoRegion(frameSize, picture, displaySize)) {
+        mInfo.mVideo.mDisplay = displaySize;
+      }
+    } else if (codecState->GetType() == OggCodecState::TYPE_VORBIS) {
+      VorbisState* vorbisState = static_cast<VorbisState*>(codecState);
+      if (!(mVorbisState && mVorbisState->mSerial == vorbisState->mSerial)) {
+        continue;
+      }
+
+      if (msgInfo) {
+        InitTrack(msgInfo,
+                  &mInfo.mAudio,
+                  mVorbisState == vorbisState);
+      }
+
+      mInfo.mAudio.mRate = vorbisState->mInfo.rate;
+      mInfo.mAudio.mChannels = vorbisState->mInfo.channels;
+      FillTags(&mInfo.mAudio, vorbisState->GetTags());
+    } else if (codecState->GetType() == OggCodecState::TYPE_OPUS) {
+      OpusState* opusState = static_cast<OpusState*>(codecState);
+      if (!(mOpusState && mOpusState->mSerial == opusState->mSerial)) {
+        continue;
+      }
+
+      if (msgInfo) {
+        InitTrack(msgInfo, &mInfo.mAudio, mOpusState == opusState);
+      }
+
+      mInfo.mAudio.mRate = opusState->mRate;
+      mInfo.mAudio.mChannels = opusState->mChannels;
+      FillTags(&mInfo.mAudio, opusState->GetTags());
+    } else if (codecState->GetType() == OggCodecState::TYPE_FLAC) {
+      FlacState* flacState = static_cast<FlacState*>(codecState);
+      if (!(mFlacState && mFlacState->mSerial == flacState->mSerial)) {
+        continue;
+      }
+
+      if (msgInfo) {
+        InitTrack(msgInfo, &mInfo.mAudio, mFlacState == flacState);
+      }
+
+      mInfo.mAudio = flacState->Info();
+      FillTags(&mInfo.mAudio, flacState->GetTags());
+    }
+  }
+}
+
+void
+OggDemuxer::FillTags(TrackInfo* aInfo, MetadataTags* aTags)
+{
+  if (!aTags) {
+    return;
+  }
+  nsAutoPtr<MetadataTags> tags(aTags);
+  for (auto iter = aTags->Iter(); !iter.Done(); iter.Next()) {
+    aInfo->mTags.AppendElement(MetadataTag(iter.Key(), iter.Data()));
+  }
+}
+
+nsresult
+OggDemuxer::ReadMetadata()
+{
+  OGG_DEBUG("OggDemuxer::ReadMetadata called!");
+
+  // We read packets until all bitstreams have read all their header packets.
+  // We record the offset of the first non-header page so that we know
+  // what page to seek to when seeking to the media start.
+
+  // @FIXME we have to read all the header packets on all the streams
+  // and THEN we can run SetupTarget*
+  // @fixme fixme
+
+  TrackInfo::TrackType tracks[2] =
+    { TrackInfo::kAudioTrack, TrackInfo::kVideoTrack };
+
+  nsTArray<OggCodecState*> bitstreams;
+  nsTArray<uint32_t> serials;
+
+  for (uint32_t i = 0; i < ArrayLength(tracks); i++) {
+    ogg_page page;
+    bool readAllBOS = false;
+    while (!readAllBOS) {
+      if (!ReadOggPage(tracks[i], &page)) {
+        // Some kind of error...
+        OGG_DEBUG("OggDemuxer::ReadOggPage failed? leaving ReadMetadata...");
+        return NS_ERROR_FAILURE;
+      }
+
+      int serial = ogg_page_serialno(&page);
+
+      if (!ogg_page_bos(&page)) {
+        // We've encountered a non Beginning Of Stream page. No more BOS pages
+        // can follow in this Ogg segment, so there will be no other bitstreams
+        // in the Ogg (unless it's invalid).
+        readAllBOS = true;
+      } else if (!mCodecStore.Contains(serial)) {
+        // We've not encountered a stream with this serial number before. Create
+        // an OggCodecState to demux it, and map that to the OggCodecState
+        // in mCodecStates.
+        OggCodecState* codecState = OggCodecState::Create(&page);
+        mCodecStore.Add(serial, codecState);
+        bitstreams.AppendElement(codecState);
+        serials.AppendElement(serial);
+      }
+      if (NS_FAILED(DemuxOggPage(tracks[i], &page))) {
+        return NS_ERROR_FAILURE;
+      }
+    }
+  }
+
+  // We've read all BOS pages, so we know the streams contained in the media.
+  // 1. Find the first encountered Theora/Vorbis/Opus bitstream, and configure
+  //    it as the target A/V bitstream.
+  // 2. Deactivate the rest of bitstreams for now, until we have MediaInfo
+  //    support multiple track infos.
+  for (uint32_t i = 0; i < bitstreams.Length(); ++i) {
+    OggCodecState* s = bitstreams[i];
+    if (s) {
+      OggHeaders headers;
+      if (s->GetType() == OggCodecState::TYPE_THEORA &&
+          ReadHeaders(TrackInfo::kVideoTrack, s, headers)) {
+        if (!mTheoraState) {
+          TheoraState* theoraState = static_cast<TheoraState*>(s);
+          SetupTargetTheora(theoraState, headers);
+        } else {
+          s->Deactivate();
+        }
+      } else if (s->GetType() == OggCodecState::TYPE_VORBIS &&
+                 ReadHeaders(TrackInfo::kAudioTrack, s, headers)) {
+        if (!mVorbisState) {
+          VorbisState* vorbisState = static_cast<VorbisState*>(s);
+          SetupTargetVorbis(vorbisState, headers);
+        } else {
+          s->Deactivate();
+        }
+      } else if (s->GetType() == OggCodecState::TYPE_OPUS &&
+                 ReadHeaders(TrackInfo::kAudioTrack, s, headers)) {
+        if (mOpusEnabled) {
+          if (!mOpusState) {
+            OpusState* opusState = static_cast<OpusState*>(s);
+            SetupTargetOpus(opusState, headers);
+          } else {
+            s->Deactivate();
+          }
+        } else {
+          NS_WARNING("Opus decoding disabled."
+                     " See media.opus.enabled in about:config");
+        }
+      } else if (MediaPrefs::FlacInOgg() &&
+                 s->GetType() == OggCodecState::TYPE_FLAC &&
+                 ReadHeaders(TrackInfo::kAudioTrack, s, headers)) {
+        if (!mFlacState) {
+          FlacState* flacState = static_cast<FlacState*>(s);
+          SetupTargetFlac(flacState, headers);
+        } else {
+          s->Deactivate();
+        }
+      } else if (s->GetType() == OggCodecState::TYPE_SKELETON && !mSkeletonState) {
+        mSkeletonState = static_cast<SkeletonState*>(s);
+      } else {
+        // Deactivate any non-primary bitstreams.
+        s->Deactivate();
+      }
+    }
+  }
+
+  SetupTargetSkeleton();
+  SetupMediaTracksInfo(serials);
+
+  if (HasAudio() || HasVideo()) {
+    int64_t startTime = -1;
+    FindStartTime(startTime);
+    if (startTime >= 0) {
+      OGG_DEBUG("Detected stream start time %lld", startTime);
+      mStartTime.emplace(startTime);
+    }
+
+    if (mInfo.mMetadataDuration.isNothing() &&
+        Resource(TrackInfo::kAudioTrack)->GetLength() >= 0) {
+      // We didn't get a duration from the index or a Content-Duration header.
+      // Seek to the end of file to find the end time.
+      int64_t length = Resource(TrackInfo::kAudioTrack)->GetLength();
+
+      NS_ASSERTION(length > 0, "Must have a content length to get end time");
+
+      int64_t endTime = RangeEndTime(TrackInfo::kAudioTrack, length);
+
+      if (endTime != -1) {
+        mInfo.mUnadjustedMetadataEndTime.emplace(TimeUnit::FromMicroseconds(endTime));
+        mInfo.mMetadataDuration.emplace(TimeUnit::FromMicroseconds(endTime - mStartTime.refOr(0)));
+        OGG_DEBUG("Got Ogg duration from seeking to end %lld", endTime);
+      }
+    }
+    if (mInfo.mMetadataDuration.isNothing()) {
+      mInfo.mMetadataDuration.emplace(TimeUnit::FromInfinity());
+    }
+    if (HasAudio()) {
+      mInfo.mAudio.mDuration = mInfo.mMetadataDuration->ToMicroseconds();
+    }
+    if (HasVideo()) {
+      mInfo.mVideo.mDuration = mInfo.mMetadataDuration->ToMicroseconds();
+    }
+  } else {
+    OGG_DEBUG("no audio or video tracks");
+    return NS_ERROR_FAILURE;
+  }
+
+  OGG_DEBUG("success?!");
+  return NS_OK;
+}
+
+void
+OggDemuxer::SetChained() {
+  {
+    if (mIsChained) {
+      return;
+    }
+    mIsChained = true;
+  }
+  if (mOnSeekableEvent) {
+    mOnSeekableEvent->Notify();
+  }
+}
+
+bool
+OggDemuxer::ReadOggChain(const media::TimeUnit& aLastEndTime)
+{
+  bool chained = false;
+  OpusState* newOpusState = nullptr;
+  VorbisState* newVorbisState = nullptr;
+  FlacState* newFlacState = nullptr;
+  nsAutoPtr<MetadataTags> tags;
+
+  if (HasVideo() || HasSkeleton() || !HasAudio()) {
+    return false;
+  }
+
+  ogg_page page;
+  if (!ReadOggPage(TrackInfo::kAudioTrack, &page) || !ogg_page_bos(&page)) {
+    // Chaining is only supported for audio only ogg files.
+    return false;
+  }
+
+  int serial = ogg_page_serialno(&page);
+  if (mCodecStore.Contains(serial)) {
+    return false;
+  }
+
+  nsAutoPtr<OggCodecState> codecState;
+  codecState = OggCodecState::Create(&page);
+  if (!codecState) {
+    return false;
+  }
+
+  if (mVorbisState && (codecState->GetType() == OggCodecState::TYPE_VORBIS)) {
+    newVorbisState = static_cast<VorbisState*>(codecState.get());
+  } else if (mOpusState && (codecState->GetType() == OggCodecState::TYPE_OPUS)) {
+    newOpusState = static_cast<OpusState*>(codecState.get());
+  } else if (mFlacState && (codecState->GetType() == OggCodecState::TYPE_FLAC)) {
+    newFlacState = static_cast<FlacState*>(codecState.get());
+  } else {
+    return false;
+  }
+
+  OggCodecState* state;
+
+  mCodecStore.Add(serial, codecState.forget());
+  state = mCodecStore.Get(serial);
+
+  NS_ENSURE_TRUE(state != nullptr, false);
+
+  if (NS_FAILED(state->PageIn(&page))) {
+    return false;
+  }
+
+  MessageField* msgInfo = nullptr;
+  if (mSkeletonState && mSkeletonState->mMsgFieldStore.Contains(serial)) {
+    mSkeletonState->mMsgFieldStore.Get(serial, &msgInfo);
+  }
+
+  OggHeaders vorbisHeaders;
+  if ((newVorbisState &&
+       ReadHeaders(TrackInfo::kAudioTrack, newVorbisState, vorbisHeaders)) &&
+      (mVorbisState->mInfo.rate == newVorbisState->mInfo.rate) &&
+      (mVorbisState->mInfo.channels == newVorbisState->mInfo.channels)) {
+
+    SetupTargetVorbis(newVorbisState, vorbisHeaders);
+    LOG(LogLevel::Debug, ("New vorbis ogg link, serial=%d\n", mVorbisSerial));
+
+    if (msgInfo) {
+      InitTrack(msgInfo, &mInfo.mAudio, true);
+    }
+    mInfo.mAudio.mMimeType = NS_LITERAL_CSTRING("audio/vorbis");
+    mInfo.mAudio.mRate = newVorbisState->mInfo.rate;
+    mInfo.mAudio.mChannels = newVorbisState->mInfo.channels;
+
+    chained = true;
+    tags = newVorbisState->GetTags();
+  }
+
+  OggHeaders opusHeaders;
+  if ((newOpusState &&
+       ReadHeaders(TrackInfo::kAudioTrack, newOpusState, opusHeaders)) &&
+      (mOpusState->mRate == newOpusState->mRate) &&
+      (mOpusState->mChannels == newOpusState->mChannels)) {
+
+    SetupTargetOpus(newOpusState, opusHeaders);
+
+    if (msgInfo) {
+      InitTrack(msgInfo, &mInfo.mAudio, true);
+    }
+    mInfo.mAudio.mMimeType = NS_LITERAL_CSTRING("audio/opus");
+    mInfo.mAudio.mRate = newOpusState->mRate;
+    mInfo.mAudio.mChannels = newOpusState->mChannels;
+
+    chained = true;
+    tags = newOpusState->GetTags();
+  }
+
+  OggHeaders flacHeaders;
+  if ((newFlacState &&
+       ReadHeaders(TrackInfo::kAudioTrack, newFlacState, flacHeaders)) &&
+      (mFlacState->Info().mRate == newFlacState->Info().mRate) &&
+      (mFlacState->Info().mChannels == newFlacState->Info().mChannels)) {
+
+    SetupTargetFlac(newFlacState, flacHeaders);
+    LOG(LogLevel::Debug, ("New flac ogg link, serial=%d\n", mFlacSerial));
+
+    if (msgInfo) {
+      InitTrack(msgInfo, &mInfo.mAudio, true);
+    }
+
+    mInfo.mAudio = newFlacState->Info();
+    chained = true;
+    tags = newFlacState->GetTags();
+  }
+
+  if (chained) {
+    SetChained();
+    mInfo.mMediaSeekable = false;
+    mDecodedAudioDuration += aLastEndTime;
+    if (mTimedMetadataEvent) {
+      mTimedMetadataEvent->Notify(
+        TimedMetadata(mDecodedAudioDuration,
+                      Move(tags),
+                      nsAutoPtr<MediaInfo>(new MediaInfo(mInfo))));
+    }
+    // Setup a new TrackInfo so that the MediaFormatReader will flush the
+    // current decoder.
+    mSharedAudioTrackInfo = new SharedTrackInfo(mInfo.mAudio, ++sStreamSourceID);
+    return true;
+  }
+
+  return false;
+}
+
+OggDemuxer::OggStateContext&
+OggDemuxer::OggState(TrackInfo::TrackType aType)
+{
+  if (aType == TrackInfo::kVideoTrack) {
+    return mVideoOggState;
+  }
+  return mAudioOggState;
+}
+
+ogg_sync_state*
+OggDemuxer::OggSyncState(TrackInfo::TrackType aType)
+{
+  return &OggState(aType).mOggState.mState;
+}
+
+MediaResourceIndex*
+OggDemuxer::Resource(TrackInfo::TrackType aType)
+{
+  return &OggState(aType).mResource;
+}
+
+MediaResourceIndex*
+OggDemuxer::CommonResource()
+{
+  return &mAudioOggState.mResource;
+}
+
+bool
+OggDemuxer::ReadOggPage(TrackInfo::TrackType aType, ogg_page* aPage)
+{
+  int ret = 0;
+  while((ret = ogg_sync_pageseek(OggSyncState(aType), aPage)) <= 0) {
+    if (ret < 0) {
+      // Lost page sync, have to skip up to next page.
+      continue;
+    }
+    // Returns a buffer that can be written too
+    // with the given size. This buffer is stored
+    // in the ogg synchronisation structure.
+    char* buffer = ogg_sync_buffer(OggSyncState(aType), 4096);
+    NS_ASSERTION(buffer, "ogg_sync_buffer failed");
+
+    // Read from the resource into the buffer
+    uint32_t bytesRead = 0;
+
+    nsresult rv = Resource(aType)->Read(buffer, 4096, &bytesRead);
+    if (NS_FAILED(rv) || !bytesRead) {
+      // End of file or error.
+      return false;
+    }
+
+    // Update the synchronisation layer with the number
+    // of bytes written to the buffer
+    ret = ogg_sync_wrote(OggSyncState(aType), bytesRead);
+    NS_ENSURE_TRUE(ret == 0, false);
+  }
+
+  return true;
+}
+
+nsresult
+OggDemuxer::DemuxOggPage(TrackInfo::TrackType aType, ogg_page* aPage)
+{
+  int serial = ogg_page_serialno(aPage);
+  OggCodecState* codecState = mCodecStore.Get(serial);
+  if (codecState == nullptr) {
+    OGG_DEBUG("encountered packet for unrecognized codecState");
+    return NS_ERROR_FAILURE;
+  }
+  if (GetCodecStateType(codecState) != aType &&
+      codecState->GetType() != OggCodecState::TYPE_SKELETON) {
+    // Not a page we're interested in.
+    return NS_OK;
+  }
+  if (NS_FAILED(codecState->PageIn(aPage))) {
+    OGG_DEBUG("codecState->PageIn failed");
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+bool
+OggDemuxer::IsSeekable() const
+{
+  if (mIsChained) {
+    return false;
+  }
+  return true;
+}
+
+UniquePtr<EncryptionInfo>
+OggDemuxer::GetCrypto()
+{
+  return nullptr;
+}
+
+ogg_packet*
+OggDemuxer::GetNextPacket(TrackInfo::TrackType aType)
+{
+  OggCodecState* state = GetTrackCodecState(aType);
+  ogg_packet* packet = nullptr;
+  OggStateContext& context = OggState(aType);
+
+  while (true) {
+    if (packet) {
+      OggCodecState::ReleasePacket(state->PacketOut());
+    }
+    DemuxUntilPacketAvailable(aType, state);
+
+    packet = state->PacketPeek();
+    if (!packet) {
+      break;
+    }
+    if (state->IsHeader(packet)) {
+      continue;
+    }
+    if (context.mNeedKeyframe && !state->IsKeyframe(packet)) {
+      continue;
+    }
+    context.mNeedKeyframe = false;
+    break;
+  }
+
+  return packet;
+}
+
+void
+OggDemuxer::DemuxUntilPacketAvailable(TrackInfo::TrackType aType,
+                                      OggCodecState* aState)
+{
+  while (!aState->IsPacketReady()) {
+    OGG_DEBUG("no packet yet, reading some more");
+    ogg_page page;
+    if (!ReadOggPage(aType, &page)) {
+      OGG_DEBUG("no more pages to read in resource?");
+      return;
+    }
+    DemuxOggPage(aType, &page);
+  }
+}
+
+TimeIntervals
+OggDemuxer::GetBuffered(TrackInfo::TrackType aType)
+{
+  if (!HaveStartTime(aType)) {
+    return TimeIntervals();
+  }
+  if (mIsChained) {
+    return TimeIntervals::Invalid();
+  }
+  TimeIntervals buffered;
+  // HasAudio and HasVideo are not used here as they take a lock and cause
+  // a deadlock. Accessing mInfo doesn't require a lock - it doesn't change
+  // after metadata is read.
+  if (!mInfo.HasValidMedia()) {
+    // No need to search through the file if there are no audio or video tracks
+    return buffered;
+  }
+
+  AutoPinned<MediaResource> resource(Resource(aType)->GetResource());
+  MediaByteRangeSet ranges;
+  nsresult res = resource->GetCachedRanges(ranges);
+  NS_ENSURE_SUCCESS(res, TimeIntervals::Invalid());
+
+  // Traverse across the buffered byte ranges, determining the time ranges
+  // they contain. MediaResource::GetNextCachedData(offset) returns -1 when
+  // offset is after the end of the media resource, or there's no more cached
+  // data after the offset. This loop will run until we've checked every
+  // buffered range in the media, in increasing order of offset.
+  nsAutoOggSyncState sync;
+  for (uint32_t index = 0; index < ranges.Length(); index++) {
+    // Ensure the offsets are after the header pages.
+    int64_t startOffset = ranges[index].mStart;
+    int64_t endOffset = ranges[index].mEnd;
+
+    // Because the granulepos time is actually the end time of the page,
+    // we special-case (startOffset == 0) so that the first
+    // buffered range always appears to be buffered from the media start
+    // time, rather than from the end-time of the first page.
+    int64_t startTime = (startOffset == 0) ? StartTime() : -1;
+
+    // Find the start time of the range. Read pages until we find one with a
+    // granulepos which we can convert into a timestamp to use as the time of
+    // the start of the buffered range.
+    ogg_sync_reset(&sync.mState);
+    while (startTime == -1) {
+      ogg_page page;
+      int32_t discard;
+      PageSyncResult pageSyncResult = PageSync(Resource(aType),
+                                               &sync.mState,
+                                               true,
+                                               startOffset,
+                                               endOffset,
+                                               &page,
+                                               discard);
+      if (pageSyncResult == PAGE_SYNC_ERROR) {
+        return TimeIntervals::Invalid();
+      } else if (pageSyncResult == PAGE_SYNC_END_OF_RANGE) {
+        // Hit the end of range without reading a page, give up trying to
+        // find a start time for this buffered range, skip onto the next one.
+        break;
+      }
+
+      int64_t granulepos = ogg_page_granulepos(&page);
+      if (granulepos == -1) {
+        // Page doesn't have an end time, advance to the next page
+        // until we find one.
+        startOffset += page.header_len + page.body_len;
+        continue;
+      }
+
+      uint32_t serial = ogg_page_serialno(&page);
+      if (aType == TrackInfo::kAudioTrack && mVorbisState &&
+          serial == mVorbisSerial) {
+        startTime = VorbisState::Time(&mVorbisInfo, granulepos);
+        NS_ASSERTION(startTime > 0, "Must have positive start time");
+      } else if (aType == TrackInfo::kAudioTrack && mOpusState &&
+                 serial == mOpusSerial) {
+        startTime = OpusState::Time(mOpusPreSkip, granulepos);
+        NS_ASSERTION(startTime > 0, "Must have positive start time");
+      } else if (aType == TrackInfo::kAudioTrack && mFlacState &&
+                 serial == mFlacSerial) {
+        startTime = mFlacState->Time(granulepos);
+        NS_ASSERTION(startTime > 0, "Must have positive start time");
+      } else if (aType == TrackInfo::kVideoTrack && mTheoraState &&
+                 serial == mTheoraSerial) {
+        startTime = TheoraState::Time(&mTheoraInfo, granulepos);
+        NS_ASSERTION(startTime > 0, "Must have positive start time");
+      } else if (mCodecStore.Contains(serial)) {
+        // Stream is not the theora or vorbis stream we're playing,
+        // but is one that we have header data for.
+        startOffset += page.header_len + page.body_len;
+        continue;
+      } else {
+        // Page is for a stream we don't know about (possibly a chained
+        // ogg), return OK to abort the finding any further ranges. This
+        // prevents us searching through the rest of the media when we
+        // may not be able to extract timestamps from it.
+        SetChained();
+        return buffered;
+      }
+    }
+
+    if (startTime != -1) {
+      // We were able to find a start time for that range, see if we can
+      // find an end time.
+      int64_t endTime = RangeEndTime(aType, startOffset, endOffset, true);
+      if (endTime > startTime) {
+        buffered += TimeInterval(
+           TimeUnit::FromMicroseconds(startTime - StartTime()),
+           TimeUnit::FromMicroseconds(endTime - StartTime()));
+      }
+    }
+  }
+
+  return buffered;
+}
+
+void
+OggDemuxer::FindStartTime(int64_t& aOutStartTime)
+{
+  // Extract the start times of the bitstreams in order to calculate
+  // the duration.
+  int64_t videoStartTime = INT64_MAX;
+  int64_t audioStartTime = INT64_MAX;
+
+  if (HasVideo()) {
+    FindStartTime(TrackInfo::kVideoTrack, videoStartTime);
+    if (videoStartTime != INT64_MAX) {
+      OGG_DEBUG("OggDemuxer::FindStartTime() video=%lld", videoStartTime);
+      mVideoOggState.mStartTime =
+        Some(TimeUnit::FromMicroseconds(videoStartTime));
+    }
+  }
+  if (HasAudio()) {
+    FindStartTime(TrackInfo::kAudioTrack, audioStartTime);
+    if (audioStartTime != INT64_MAX) {
+      OGG_DEBUG("OggDemuxer::FindStartTime() audio=%lld", audioStartTime);
+      mAudioOggState.mStartTime =
+        Some(TimeUnit::FromMicroseconds(audioStartTime));
+    }
+  }
+
+  int64_t startTime = std::min(videoStartTime, audioStartTime);
+  if (startTime != INT64_MAX) {
+    aOutStartTime = startTime;
+  }
+}
+
+void
+OggDemuxer::FindStartTime(TrackInfo::TrackType aType, int64_t& aOutStartTime)
+{
+  int64_t startTime = INT64_MAX;
+
+  OggCodecState* state = GetTrackCodecState(aType);
+  ogg_packet* pkt = GetNextPacket(aType);
+  if (pkt) {
+    startTime = state->PacketStartTime(pkt);
+  }
+
+  if (startTime != INT64_MAX) {
+    aOutStartTime = startTime;
+  }
+}
+
+nsresult
+OggDemuxer::SeekInternal(TrackInfo::TrackType aType, const TimeUnit& aTarget)
+{
+  int64_t target = aTarget.ToMicroseconds();
+  OGG_DEBUG("About to seek to %lld", target);
+  nsresult res;
+  int64_t adjustedTarget = target;
+  int64_t startTime = StartTime(aType);
+  int64_t endTime = mInfo.mMetadataDuration->ToMicroseconds();
+  if (aType == TrackInfo::kAudioTrack && mOpusState){
+    adjustedTarget = std::max(startTime, target - OGG_SEEK_OPUS_PREROLL);
+  }
+
+  if (!HaveStartTime(aType) || adjustedTarget == startTime) {
+    // We've seeked to the media start or we can't seek.
+    // Just seek to the offset of the first content page.
+    res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, 0);
+    NS_ENSURE_SUCCESS(res,res);
+
+    res = Reset(aType);
+    NS_ENSURE_SUCCESS(res,res);
+  } else {
+    // TODO: This may seek back unnecessarily far in the video, but we don't
+    // have a way of asking Skeleton to seek to a different target for each
+    // stream yet. Using adjustedTarget here is at least correct, if slow.
+    IndexedSeekResult sres = SeekToKeyframeUsingIndex(aType, adjustedTarget);
+    NS_ENSURE_TRUE(sres != SEEK_FATAL_ERROR, NS_ERROR_FAILURE);
+    if (sres == SEEK_INDEX_FAIL) {
+      // No index or other non-fatal index-related failure. Try to seek
+      // using a bisection search. Determine the already downloaded data
+      // in the media cache, so we can try to seek in the cached data first.
+      AutoTArray<SeekRange, 16> ranges;
+      res = GetSeekRanges(aType, ranges);
+      NS_ENSURE_SUCCESS(res,res);
+
+      // Figure out if the seek target lies in a buffered range.
+      SeekRange r = SelectSeekRange(aType, ranges, target, startTime, endTime, true);
+
+      if (!r.IsNull()) {
+        // We know the buffered range in which the seek target lies, do a
+        // bisection search in that buffered range.
+        res = SeekInBufferedRange(aType, target, adjustedTarget, startTime, endTime, ranges, r);
+        NS_ENSURE_SUCCESS(res,res);
+      } else {
+        // The target doesn't lie in a buffered range. Perform a bisection
+        // search over the whole media, using the known buffered ranges to
+        // reduce the search space.
+        res = SeekInUnbuffered(aType, target, startTime, endTime, ranges);
+        NS_ENSURE_SUCCESS(res,res);
+      }
+    }
+  }
+
+  // Demux forwards until we find the first keyframe prior the target.
+  // there may be non-keyframes in the page before the keyframe.
+  // Additionally, we may have seeked to the first page referenced by the
+  // page index which may be quite far off the target.
+  // When doing fastSeek we display the first frame after the seek, so
+  // we need to advance the decode to the keyframe otherwise we'll get
+  // visual artifacts in the first frame output after the seek.
+  OggCodecState* state = GetTrackCodecState(aType);
+  OggPacketQueue tempPackets;
+  bool foundKeyframe = false;
+  while (true) {
+    DemuxUntilPacketAvailable(aType, state);
+    ogg_packet* packet = state->PacketPeek();
+    if (packet == nullptr) {
+      OGG_DEBUG("End of stream reached before keyframe found in indexed seek");
+      break;
+    }
+    int64_t startTstamp = state->PacketStartTime(packet);
+    if (foundKeyframe && startTstamp > adjustedTarget) {
+      break;
+    }
+    if (state->IsKeyframe(packet)) {
+      OGG_DEBUG("keyframe found after seeking at %lld", startTstamp);
+      tempPackets.Erase();
+      foundKeyframe = true;
+    }
+    if (foundKeyframe && startTstamp == adjustedTarget) {
+      break;
+    }
+    ogg_packet* releaseMe = state->PacketOut();
+    if (foundKeyframe) {
+      tempPackets.Append(releaseMe);
+    } else {
+      // Discard video packets before the first keyframe.
+      OggCodecState::ReleasePacket(releaseMe);
+    }
+  }
+  // Re-add all packet into the codec state in order.
+  state->PushFront(Move(tempPackets));
+
+  return NS_OK;
+}
+
+OggDemuxer::IndexedSeekResult
+OggDemuxer::RollbackIndexedSeek(TrackInfo::TrackType aType, int64_t aOffset)
+{
+  if (mSkeletonState) {
+    mSkeletonState->Deactivate();
+  }
+  nsresult res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, aOffset);
+  NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR);
+  return SEEK_INDEX_FAIL;
+}
+
+OggDemuxer::IndexedSeekResult
+OggDemuxer::SeekToKeyframeUsingIndex(TrackInfo::TrackType aType, int64_t aTarget)
+{
+  if (!HasSkeleton() || !mSkeletonState->HasIndex()) {
+    return SEEK_INDEX_FAIL;
+  }
+  // We have an index from the Skeleton track, try to use it to seek.
+  AutoTArray<uint32_t, 2> tracks;
+  BuildSerialList(tracks);
+  SkeletonState::nsSeekTarget keyframe;
+  if (NS_FAILED(mSkeletonState->IndexedSeekTarget(aTarget,
+                                                  tracks,
+                                                  keyframe))) {
+    // Could not locate a keypoint for the target in the index.
+    return SEEK_INDEX_FAIL;
+  }
+
+  // Remember original resource read cursor position so we can rollback on failure.
+  int64_t tell = Resource(aType)->Tell();
+
+  // Seek to the keypoint returned by the index.
+  if (keyframe.mKeyPoint.mOffset > Resource(aType)->GetLength() ||
+      keyframe.mKeyPoint.mOffset < 0) {
+    // Index must be invalid.
+    return RollbackIndexedSeek(aType, tell);
+  }
+  LOG(LogLevel::Debug, ("Seeking using index to keyframe at offset %lld\n",
+                     keyframe.mKeyPoint.mOffset));
+  nsresult res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET,
+                                       keyframe.mKeyPoint.mOffset);
+  NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR);
+
+  // We've moved the read set, so reset decode.
+  res = Reset(aType);
+  NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR);
+
+  // Check that the page the index thinks is exactly here is actually exactly
+  // here. If not, the index is invalid.
+  ogg_page page;
+  int skippedBytes = 0;
+  PageSyncResult syncres = PageSync(Resource(aType),
+                                    OggSyncState(aType),
+                                    false,
+                                    keyframe.mKeyPoint.mOffset,
+                                    Resource(aType)->GetLength(),
+                                    &page,
+                                    skippedBytes);
+  NS_ENSURE_TRUE(syncres != PAGE_SYNC_ERROR, SEEK_FATAL_ERROR);
+  if (syncres != PAGE_SYNC_OK || skippedBytes != 0) {
+    LOG(LogLevel::Debug, ("Indexed-seek failure: Ogg Skeleton Index is invalid "
+                       "or sync error after seek"));
+    return RollbackIndexedSeek(aType, tell);
+  }
+  uint32_t serial = ogg_page_serialno(&page);
+  if (serial != keyframe.mSerial) {
+    // Serialno of page at offset isn't what the index told us to expect.
+    // Assume the index is invalid.
+    return RollbackIndexedSeek(aType, tell);
+  }
+  OggCodecState* codecState = mCodecStore.Get(serial);
+  if (codecState && codecState->mActive &&
+      ogg_stream_pagein(&codecState->mState, &page) != 0) {
+    // Couldn't insert page into the ogg resource, or somehow the resource
+    // is no longer active.
+    return RollbackIndexedSeek(aType, tell);
+  }
+  return SEEK_OK;
+}
+
+// Reads a page from the media resource.
+OggDemuxer::PageSyncResult
+OggDemuxer::PageSync(MediaResourceIndex* aResource,
+                     ogg_sync_state* aState,
+                     bool aCachedDataOnly,
+                     int64_t aOffset,
+                     int64_t aEndOffset,
+                     ogg_page* aPage,
+                     int& aSkippedBytes)
+{
+  aSkippedBytes = 0;
+  // Sync to the next page.
+  int ret = 0;
+  uint32_t bytesRead = 0;
+  int64_t readHead = aOffset;
+  while (ret <= 0) {
+    ret = ogg_sync_pageseek(aState, aPage);
+    if (ret == 0) {
+      char* buffer = ogg_sync_buffer(aState, PAGE_STEP);
+      NS_ASSERTION(buffer, "Must have a buffer");
+
+      // Read from the file into the buffer
+      int64_t bytesToRead = std::min(static_cast<int64_t>(PAGE_STEP),
+                                   aEndOffset - readHead);
+      NS_ASSERTION(bytesToRead <= UINT32_MAX, "bytesToRead range check");
+      if (bytesToRead <= 0) {
+        return PAGE_SYNC_END_OF_RANGE;
+      }
+      nsresult rv = NS_OK;
+      if (aCachedDataOnly) {
+        rv = aResource->GetResource()->ReadFromCache(buffer, readHead,
+                                                     static_cast<uint32_t>(bytesToRead));
+        NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR);
+        bytesRead = static_cast<uint32_t>(bytesToRead);
+      } else {
+        rv = aResource->Seek(nsISeekableStream::NS_SEEK_SET, readHead);
+        NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR);
+        rv = aResource->Read(buffer,
+                             static_cast<uint32_t>(bytesToRead),
+                             &bytesRead);
+        NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR);
+      }
+      if (bytesRead == 0 && NS_SUCCEEDED(rv)) {
+        // End of file.
+        return PAGE_SYNC_END_OF_RANGE;
+      }
+      readHead += bytesRead;
+
+      // Update the synchronisation layer with the number
+      // of bytes written to the buffer
+      ret = ogg_sync_wrote(aState, bytesRead);
+      NS_ENSURE_TRUE(ret == 0, PAGE_SYNC_ERROR);
+      continue;
+    }
+
+    if (ret < 0) {
+      NS_ASSERTION(aSkippedBytes >= 0, "Offset >= 0");
+      aSkippedBytes += -ret;
+      NS_ASSERTION(aSkippedBytes >= 0, "Offset >= 0");
+      continue;
+    }
+  }
+
+  return PAGE_SYNC_OK;
+}
+
+//OggTrackDemuxer
+OggTrackDemuxer::OggTrackDemuxer(OggDemuxer* aParent,
+                                 TrackInfo::TrackType aType,
+                                 uint32_t aTrackNumber)
+  : mParent(aParent)
+  , mType(aType)
+{
+  mInfo = mParent->GetTrackInfo(aType, aTrackNumber);
+  MOZ_ASSERT(mInfo);
+}
+
+OggTrackDemuxer::~OggTrackDemuxer()
+{
+}
+
+UniquePtr<TrackInfo>
+OggTrackDemuxer::GetInfo() const
+{
+  return mInfo->Clone();
+}
+
+RefPtr<OggTrackDemuxer::SeekPromise>
+OggTrackDemuxer::Seek(TimeUnit aTime)
+{
+  // Seeks to aTime. Upon success, SeekPromise will be resolved with the
+  // actual time seeked to. Typically the random access point time
+  mQueuedSample = nullptr;
+  TimeUnit seekTime = aTime;
+  if (mParent->SeekInternal(mType, aTime) == NS_OK) {
+    RefPtr<MediaRawData> sample(NextSample());
+
+    // Check what time we actually seeked to.
+    if (sample != nullptr) {
+      seekTime = TimeUnit::FromMicroseconds(sample->mTime);
+      OGG_DEBUG("%p seeked to time %lld", this, seekTime.ToMicroseconds());
+    }
+    mQueuedSample = sample;
+
+    return SeekPromise::CreateAndResolve(seekTime, __func__);
+  } else {
+    return SeekPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR, __func__);
+  }
+}
+
+RefPtr<MediaRawData>
+OggTrackDemuxer::NextSample()
+{
+  if (mQueuedSample) {
+    RefPtr<MediaRawData> nextSample = mQueuedSample;
+    mQueuedSample = nullptr;
+    if (mType == TrackInfo::kAudioTrack) {
+      nextSample->mTrackInfo = mParent->mSharedAudioTrackInfo;
+    }
+    return nextSample;
+  }
+  ogg_packet* packet = mParent->GetNextPacket(mType);
+  if (!packet) {
+    return nullptr;
+  }
+  // Check the eos state in case we need to look for chained streams.
+  bool eos = packet->e_o_s;
+  OggCodecState* state = mParent->GetTrackCodecState(mType);
+  RefPtr<MediaRawData> data = state->PacketOutAsMediaRawData();
+  if (!data) {
+    return nullptr;
+  }
+  if (mType == TrackInfo::kAudioTrack) {
+    data->mTrackInfo = mParent->mSharedAudioTrackInfo;
+  }
+  if (eos) {
+    // We've encountered an end of bitstream packet; check for a chained
+    // bitstream following this one.
+    // This will also update mSharedAudioTrackInfo.
+    mParent->ReadOggChain(TimeUnit::FromMicroseconds(data->GetEndTime()));
+  }
+  return data;
+}
+
+RefPtr<OggTrackDemuxer::SamplesPromise>
+OggTrackDemuxer::GetSamples(int32_t aNumSamples)
+{
+  RefPtr<SamplesHolder> samples = new SamplesHolder;
+  if (!aNumSamples) {
+    return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR, __func__);
+  }
+
+  while (aNumSamples) {
+    RefPtr<MediaRawData> sample(NextSample());
+    if (!sample) {
+      break;
+    }
+    samples->mSamples.AppendElement(sample);
+    aNumSamples--;
+  }
+
+  if (samples->mSamples.IsEmpty()) {
+    return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_END_OF_STREAM, __func__);
+  } else {
+    return SamplesPromise::CreateAndResolve(samples, __func__);
+  }
+}
+
+void
+OggTrackDemuxer::Reset()
+{
+  mParent->Reset(mType);
+  mQueuedSample = nullptr;
+}
+
+RefPtr<OggTrackDemuxer::SkipAccessPointPromise>
+OggTrackDemuxer::SkipToNextRandomAccessPoint(TimeUnit aTimeThreshold)
+{
+  uint32_t parsed = 0;
+  bool found = false;
+  RefPtr<MediaRawData> sample;
+
+  OGG_DEBUG("TimeThreshold: %f", aTimeThreshold.ToSeconds());
+  while (!found && (sample = NextSample())) {
+    parsed++;
+    if (sample->mKeyframe && sample->mTime >= aTimeThreshold.ToMicroseconds()) {
+      found = true;
+      mQueuedSample = sample;
+    }
+  }
+  if (found) {
+    OGG_DEBUG("next sample: %f (parsed: %d)",
+               TimeUnit::FromMicroseconds(sample->mTime).ToSeconds(),
+               parsed);
+    return SkipAccessPointPromise::CreateAndResolve(parsed, __func__);
+  } else {
+    SkipFailureHolder failure(NS_ERROR_DOM_MEDIA_END_OF_STREAM, parsed);
+    return SkipAccessPointPromise::CreateAndReject(Move(failure), __func__);
+  }
+}
+
+TimeIntervals
+OggTrackDemuxer::GetBuffered()
+{
+  return mParent->GetBuffered(mType);
+}
+
+void
+OggTrackDemuxer::BreakCycles()
+{
+  mParent = nullptr;
+}
+
+
+// Returns an ogg page's checksum.
+ogg_uint32_t
+OggDemuxer::GetPageChecksum(ogg_page* page)
+{
+  if (page == 0 || page->header == 0 || page->header_len < 25) {
+    return 0;
+  }
+  const unsigned char* p = page->header + 22;
+  uint32_t c = p[0] + (p[1] << 8) + (p[2] << 16) + (p[3] << 24);
+  return c;
+}
+
+int64_t
+OggDemuxer::RangeStartTime(TrackInfo::TrackType aType, int64_t aOffset)
+{
+  int64_t position = Resource(aType)->Tell();
+  nsresult res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, aOffset);
+  NS_ENSURE_SUCCESS(res, 0);
+  int64_t startTime = 0;
+  FindStartTime(aType, startTime);
+  res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, position);
+  NS_ENSURE_SUCCESS(res, -1);
+  return startTime;
+}
+
+struct nsDemuxerAutoOggSyncState
+{
+  nsDemuxerAutoOggSyncState()
+  {
+    ogg_sync_init(&mState);
+  }
+  ~nsDemuxerAutoOggSyncState()
+  {
+    ogg_sync_clear(&mState);
+  }
+  ogg_sync_state mState;
+};
+
+int64_t
+OggDemuxer::RangeEndTime(TrackInfo::TrackType aType, int64_t aEndOffset)
+{
+  int64_t position = Resource(aType)->Tell();
+  int64_t endTime = RangeEndTime(aType, 0, aEndOffset, false);
+  nsresult res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, position);
+  NS_ENSURE_SUCCESS(res, -1);
+  return endTime;
+}
+
+int64_t
+OggDemuxer::RangeEndTime(TrackInfo::TrackType aType,
+                         int64_t aStartOffset,
+                         int64_t aEndOffset,
+                         bool aCachedDataOnly)
+{
+  nsDemuxerAutoOggSyncState sync;
+
+  // We need to find the last page which ends before aEndOffset that
+  // has a granulepos that we can convert to a timestamp. We do this by
+  // backing off from aEndOffset until we encounter a page on which we can
+  // interpret the granulepos. If while backing off we encounter a page which
+  // we've previously encountered before, we'll either backoff again if we
+  // haven't found an end time yet, or return the last end time found.
+  const int step = 5000;
+  const int maxOggPageSize = 65306;
+  int64_t readStartOffset = aEndOffset;
+  int64_t readLimitOffset = aEndOffset;
+  int64_t readHead = aEndOffset;
+  int64_t endTime = -1;
+  uint32_t checksumAfterSeek = 0;
+  uint32_t prevChecksumAfterSeek = 0;
+  bool mustBackOff = false;
+  while (true) {
+    ogg_page page;
+    int ret = ogg_sync_pageseek(&sync.mState, &page);
+    if (ret == 0) {
+      // We need more data if we've not encountered a page we've seen before,
+      // or we've read to the end of file.
+      if (mustBackOff || readHead == aEndOffset || readHead == aStartOffset) {
+        if (endTime != -1 || readStartOffset == 0) {
+          // We have encountered a page before, or we're at the end of file.
+          break;
+        }
+        mustBackOff = false;
+        prevChecksumAfterSeek = checksumAfterSeek;
+        checksumAfterSeek = 0;
+        ogg_sync_reset(&sync.mState);
+        readStartOffset = std::max(static_cast<int64_t>(0), readStartOffset - step);
+        // There's no point reading more than the maximum size of
+        // an Ogg page into data we've previously scanned. Any data
+        // between readLimitOffset and aEndOffset must be garbage
+        // and we can ignore it thereafter.
+        readLimitOffset = std::min(readLimitOffset,
+                                   readStartOffset + maxOggPageSize);
+        readHead = std::max(aStartOffset, readStartOffset);
+      }
+
+      int64_t limit = std::min(static_cast<int64_t>(UINT32_MAX),
+                               aEndOffset - readHead);
+      limit = std::max(static_cast<int64_t>(0), limit);
+      limit = std::min(limit, static_cast<int64_t>(step));
+      uint32_t bytesToRead = static_cast<uint32_t>(limit);
+      uint32_t bytesRead = 0;
+      char* buffer = ogg_sync_buffer(&sync.mState, bytesToRead);
+      NS_ASSERTION(buffer, "Must have buffer");
+      nsresult res;
+      if (aCachedDataOnly) {
+        res = Resource(aType)->GetResource()->ReadFromCache(buffer, readHead, bytesToRead);
+        NS_ENSURE_SUCCESS(res, -1);
+        bytesRead = bytesToRead;
+      } else {
+        NS_ASSERTION(readHead < aEndOffset,
+                     "resource pos must be before range end");
+        res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, readHead);
+        NS_ENSURE_SUCCESS(res, -1);
+        res = Resource(aType)->Read(buffer, bytesToRead, &bytesRead);
+        NS_ENSURE_SUCCESS(res, -1);
+      }
+      readHead += bytesRead;
+      if (readHead > readLimitOffset) {
+        mustBackOff = true;
+      }
+
+      // Update the synchronisation layer with the number
+      // of bytes written to the buffer
+      ret = ogg_sync_wrote(&sync.mState, bytesRead);
+      if (ret != 0) {
+        endTime = -1;
+        break;
+      }
+      continue;
+    }
+
+    if (ret < 0 || ogg_page_granulepos(&page) < 0) {
+      continue;
+    }
+
+    uint32_t checksum = GetPageChecksum(&page);
+    if (checksumAfterSeek == 0) {
+      // This is the first page we've decoded after a backoff/seek. Remember
+      // the page checksum. If we backoff further and encounter this page
+      // again, we'll know that we won't find a page with an end time after
+      // this one, so we'll know to back off again.
+      checksumAfterSeek = checksum;
+    }
+    if (checksum == prevChecksumAfterSeek) {
+      // This page has the same checksum as the first page we encountered
+      // after the last backoff/seek. Since we've already scanned after this
+      // page and failed to find an end time, we may as well backoff again and
+      // try to find an end time from an earlier page.
+      mustBackOff = true;
+      continue;
+    }
+
+    int64_t granulepos = ogg_page_granulepos(&page);
+    int serial = ogg_page_serialno(&page);
+
+    OggCodecState* codecState = nullptr;
+    codecState = mCodecStore.Get(serial);
+    if (!codecState) {
+      // This page is from a bitstream which we haven't encountered yet.
+      // It's probably from a new "link" in a "chained" ogg. Don't
+      // bother even trying to find a duration...
+      SetChained();
+      endTime = -1;
+      break;
+    }
+
+    int64_t t = codecState->Time(granulepos);
+    if (t != -1) {
+      endTime = t;
+    }
+  }
+
+  return endTime;
+}
+
+nsresult
+OggDemuxer::GetSeekRanges(TrackInfo::TrackType aType,
+                          nsTArray<SeekRange>& aRanges)
+{
+  AutoPinned<MediaResource> resource(Resource(aType)->GetResource());
+  MediaByteRangeSet cached;
+  nsresult res = resource->GetCachedRanges(cached);
+  NS_ENSURE_SUCCESS(res, res);
+
+  for (uint32_t index = 0; index < cached.Length(); index++) {
+    auto& range = cached[index];
+    int64_t startTime = -1;
+    int64_t endTime = -1;
+    if (NS_FAILED(Reset(aType))) {
+      return NS_ERROR_FAILURE;
+    }
+    int64_t startOffset = range.mStart;
+    int64_t endOffset = range.mEnd;
+    startTime = RangeStartTime(aType, startOffset);
+    if (startTime != -1 &&
+        ((endTime = RangeEndTime(aType, endOffset)) != -1)) {
+      NS_WARNING_ASSERTION(startTime < endTime,
+                           "Start time must be before end time");
+      aRanges.AppendElement(SeekRange(startOffset,
+                                      endOffset,
+                                      startTime,
+                                      endTime));
+     }
+  }
+  if (NS_FAILED(Reset(aType))) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+OggDemuxer::SeekRange
+OggDemuxer::SelectSeekRange(TrackInfo::TrackType aType,
+                            const nsTArray<SeekRange>& ranges,
+                            int64_t aTarget,
+                            int64_t aStartTime,
+                            int64_t aEndTime,
+                            bool aExact)
+{
+  int64_t so = 0;
+  int64_t eo = Resource(aType)->GetLength();
+  int64_t st = aStartTime;
+  int64_t et = aEndTime;
+  for (uint32_t i = 0; i < ranges.Length(); i++) {
+    const SeekRange& r = ranges[i];
+    if (r.mTimeStart < aTarget) {
+      so = r.mOffsetStart;
+      st = r.mTimeStart;
+    }
+    if (r.mTimeEnd >= aTarget && r.mTimeEnd < et) {
+      eo = r.mOffsetEnd;
+      et = r.mTimeEnd;
+    }
+
+    if (r.mTimeStart < aTarget && aTarget <= r.mTimeEnd) {
+      // Target lies exactly in this range.
+      return ranges[i];
+    }
+  }
+  if (aExact || eo == -1) {
+    return SeekRange();
+  }
+  return SeekRange(so, eo, st, et);
+}
+
+
+nsresult
+OggDemuxer::SeekInBufferedRange(TrackInfo::TrackType aType,
+                                int64_t aTarget,
+                                int64_t aAdjustedTarget,
+                                int64_t aStartTime,
+                                int64_t aEndTime,
+                                const nsTArray<SeekRange>& aRanges,
+                                const SeekRange& aRange)
+{
+  OGG_DEBUG("Seeking in buffered data to %lld using bisection search", aTarget);
+  if (aType == TrackInfo::kVideoTrack || aAdjustedTarget >= aTarget) {
+    // We know the exact byte range in which the target must lie. It must
+    // be buffered in the media cache. Seek there.
+    nsresult res = SeekBisection(aType, aTarget, aRange, 0);
+    if (NS_FAILED(res) || aType != TrackInfo::kVideoTrack) {
+      return res;
+    }
+
+    // We have an active Theora bitstream. Peek the next Theora frame, and
+    // extract its keyframe's time.
+    DemuxUntilPacketAvailable(aType, mTheoraState);
+    ogg_packet* packet = mTheoraState->PacketPeek();
+    if (packet && !mTheoraState->IsKeyframe(packet)) {
+      // First post-seek frame isn't a keyframe, seek back to previous keyframe,
+      // otherwise we'll get visual artifacts.
+      NS_ASSERTION(packet->granulepos != -1, "Must have a granulepos");
+      int shift = mTheoraState->mInfo.keyframe_granule_shift;
+      int64_t keyframeGranulepos = (packet->granulepos >> shift) << shift;
+      int64_t keyframeTime = mTheoraState->StartTime(keyframeGranulepos);
+      SEEK_LOG(LogLevel::Debug, ("Keyframe for %lld is at %lld, seeking back to it",
+                              frameTime, keyframeTime));
+      aAdjustedTarget = std::min(aAdjustedTarget, keyframeTime);
+    }
+  }
+
+  nsresult res = NS_OK;
+  if (aAdjustedTarget < aTarget) {
+    SeekRange k = SelectSeekRange(aType,
+                                  aRanges,
+                                  aAdjustedTarget,
+                                  aStartTime,
+                                  aEndTime,
+                                  false);
+    res = SeekBisection(aType, aAdjustedTarget, k, OGG_SEEK_FUZZ_USECS);
+  }
+  return res;
+}
+
+nsresult
+OggDemuxer::SeekInUnbuffered(TrackInfo::TrackType aType,
+                             int64_t aTarget,
+                             int64_t aStartTime,
+                             int64_t aEndTime,
+                             const nsTArray<SeekRange>& aRanges)
+{
+  OGG_DEBUG("Seeking in unbuffered data to %lld using bisection search", aTarget);
+
+  // If we've got an active Theora bitstream, determine the maximum possible
+  // time in usecs which a keyframe could be before a given interframe. We
+  // subtract this from our seek target, seek to the new target, and then
+  // will decode forward to the original seek target. We should encounter a
+  // keyframe in that interval. This prevents us from needing to run two
+  // bisections; one for the seek target frame, and another to find its
+  // keyframe. It's usually faster to just download this extra data, rather
+  // tham perform two bisections to find the seek target's keyframe. We
+  // don't do this offsetting when seeking in a buffered range,
+  // as the extra decoding causes a noticeable speed hit when all the data
+  // is buffered (compared to just doing a bisection to exactly find the
+  // keyframe).
+  int64_t keyframeOffsetMs = 0;
+  if (aType == TrackInfo::kVideoTrack && mTheoraState) {
+    keyframeOffsetMs = mTheoraState->MaxKeyframeOffset();
+  }
+  // Add in the Opus pre-roll if necessary, as well.
+  if (aType == TrackInfo::kAudioTrack && mOpusState) {
+    keyframeOffsetMs = std::max(keyframeOffsetMs, OGG_SEEK_OPUS_PREROLL);
+  }
+  int64_t seekTarget = std::max(aStartTime, aTarget - keyframeOffsetMs);
+  // Minimize the bisection search space using the known timestamps from the
+  // buffered ranges.
+  SeekRange k =
+    SelectSeekRange(aType, aRanges, seekTarget, aStartTime, aEndTime, false);
+  return SeekBisection(aType, seekTarget, k, OGG_SEEK_FUZZ_USECS);
+}
+
+nsresult
+OggDemuxer::SeekBisection(TrackInfo::TrackType aType,
+                          int64_t aTarget,
+                          const SeekRange& aRange,
+                          uint32_t aFuzz)
+{
+  nsresult res;
+
+  if (aTarget <= aRange.mTimeStart) {
+    if (NS_FAILED(Reset(aType))) {
+      return NS_ERROR_FAILURE;
+    }
+    res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, 0);
+    NS_ENSURE_SUCCESS(res,res);
+    return NS_OK;
+  }
+
+  // Bisection search, find start offset of last page with end time less than
+  // the seek target.
+  ogg_int64_t startOffset = aRange.mOffsetStart;
+  ogg_int64_t startTime = aRange.mTimeStart;
+  ogg_int64_t startLength = 0; // Length of the page at startOffset.
+  ogg_int64_t endOffset = aRange.mOffsetEnd;
+  ogg_int64_t endTime = aRange.mTimeEnd;
+
+  ogg_int64_t seekTarget = aTarget;
+  int64_t seekLowerBound = std::max(static_cast<int64_t>(0), aTarget - aFuzz);
+  int hops = 0;
+  DebugOnly<ogg_int64_t> previousGuess = -1;
+  int backsteps = 0;
+  const int maxBackStep = 10;
+  NS_ASSERTION(static_cast<uint64_t>(PAGE_STEP) * pow(2.0, maxBackStep) < INT32_MAX,
+               "Backstep calculation must not overflow");
+
+  // Seek via bisection search. Loop until we find the offset where the page
+  // before the offset is before the seek target, and the page after the offset
+  // is after the seek target.
+  while (true) {
+    ogg_int64_t duration = 0;
+    double target = 0;
+    ogg_int64_t interval = 0;
+    ogg_int64_t guess = 0;
+    ogg_page page;
+    int skippedBytes = 0;
+    ogg_int64_t pageOffset = 0;
+    ogg_int64_t pageLength = 0;
+    ogg_int64_t granuleTime = -1;
+    bool mustBackoff = false;
+
+    // Guess where we should bisect to, based on the bit rate and the time
+    // remaining in the interval. Loop until we can determine the time at
+    // the guess offset.
+    while (true) {
+
+      // Discard any previously buffered packets/pages.
+      if (NS_FAILED(Reset(aType))) {
+        return NS_ERROR_FAILURE;
+      }
+
+      interval = endOffset - startOffset - startLength;
+      if (interval == 0) {
+        // Our interval is empty, we've found the optimal seek point, as the
+        // page at the start offset is before the seek target, and the page
+        // at the end offset is after the seek target.
+        SEEK_LOG(LogLevel::Debug, ("Interval narrowed, terminating bisection."));
+        break;
+      }
+
+      // Guess bisection point.
+      duration = endTime - startTime;
+      target = (double)(seekTarget - startTime) / (double)duration;
+      guess = startOffset + startLength +
+              static_cast<ogg_int64_t>((double)interval * target);
+      guess = std::min(guess, endOffset - PAGE_STEP);
+      if (mustBackoff) {
+        // We previously failed to determine the time at the guess offset,
+        // probably because we ran out of data to decode. This usually happens
+        // when we guess very close to the end offset. So reduce the guess
+        // offset using an exponential backoff until we determine the time.
+        SEEK_LOG(LogLevel::Debug, ("Backing off %d bytes, backsteps=%d",
+          static_cast<int32_t>(PAGE_STEP * pow(2.0, backsteps)), backsteps));
+        guess -= PAGE_STEP * static_cast<ogg_int64_t>(pow(2.0, backsteps));
+
+        if (guess <= startOffset) {
+          // We've tried to backoff to before the start offset of our seek
+          // range. This means we couldn't find a seek termination position
+          // near the end of the seek range, so just set the seek termination
+          // condition, and break out of the bisection loop. We'll begin
+          // decoding from the start of the seek range.
+          interval = 0;
+          break;
+        }
+
+        backsteps = std::min(backsteps + 1, maxBackStep);
+        // We reset mustBackoff. If we still need to backoff further, it will
+        // be set to true again.
+        mustBackoff = false;
+      } else {
+        backsteps = 0;
+      }
+      guess = std::max(guess, startOffset + startLength);
+
+      SEEK_LOG(LogLevel::Debug, ("Seek loop start[o=%lld..%lld t=%lld] "
+                              "end[o=%lld t=%lld] "
+                              "interval=%lld target=%lf guess=%lld",
+                              startOffset, (startOffset+startLength), startTime,
+                              endOffset, endTime, interval, target, guess));
+
+      NS_ASSERTION(guess >= startOffset + startLength, "Guess must be after range start");
+      NS_ASSERTION(guess < endOffset, "Guess must be before range end");
+      NS_ASSERTION(guess != previousGuess, "Guess should be different to previous");
+      previousGuess = guess;
+
+      hops++;
+
+      // Locate the next page after our seek guess, and then figure out the
+      // granule time of the audio and video bitstreams there. We can then
+      // make a bisection decision based on our location in the media.
+      PageSyncResult pageSyncResult = PageSync(Resource(aType),
+                                               OggSyncState(aType),
+                                               false,
+                                               guess,
+                                               endOffset,
+                                               &page,
+                                               skippedBytes);
+      NS_ENSURE_TRUE(pageSyncResult != PAGE_SYNC_ERROR, NS_ERROR_FAILURE);
+
+      if (pageSyncResult == PAGE_SYNC_END_OF_RANGE) {
+        // Our guess was too close to the end, we've ended up reading the end
+        // page. Backoff exponentially from the end point, in case the last
+        // page/frame/sample is huge.
+        mustBackoff = true;
+        SEEK_LOG(LogLevel::Debug, ("Hit the end of range, backing off"));
+        continue;
+      }
+
+      // We've located a page of length |ret| at |guess + skippedBytes|.
+      // Remember where the page is located.
+      pageOffset = guess + skippedBytes;
+      pageLength = page.header_len + page.body_len;
+
+      // Read pages until we can determine the granule time of the audio and
+      // video bitstream.
+      ogg_int64_t audioTime = -1;
+      ogg_int64_t videoTime = -1;
+      do {
+        // Add the page to its codec state, determine its granule time.
+        uint32_t serial = ogg_page_serialno(&page);
+        OggCodecState* codecState = mCodecStore.Get(serial);
+        if (codecState && GetCodecStateType(codecState) == aType) {
+          if (codecState->mActive) {
+            int ret = ogg_stream_pagein(&codecState->mState, &page);
+            NS_ENSURE_TRUE(ret == 0, NS_ERROR_FAILURE);
+          }
+
+          ogg_int64_t granulepos = ogg_page_granulepos(&page);
+
+          if (aType == TrackInfo::kAudioTrack &&
+              granulepos > 0 && audioTime == -1) {
+            if (mVorbisState && serial == mVorbisState->mSerial) {
+              audioTime = mVorbisState->Time(granulepos);
+            } else if (mOpusState && serial == mOpusState->mSerial) {
+              audioTime = mOpusState->Time(granulepos);
+            } else if (mFlacState && serial == mFlacState->mSerial) {
+              audioTime = mFlacState->Time(granulepos);
+            }
+          }
+
+          if (aType == TrackInfo::kVideoTrack &&
+              granulepos > 0 && serial == mTheoraState->mSerial &&
+              videoTime == -1) {
+            videoTime = mTheoraState->Time(granulepos);
+          }
+
+          if (pageOffset + pageLength >= endOffset) {
+            // Hit end of readable data.
+            break;
+          }
+        }
+        if (!ReadOggPage(aType, &page)) {
+          break;
+        }
+
+      } while ((aType == TrackInfo::kAudioTrack && audioTime == -1) ||
+               (aType == TrackInfo::kVideoTrack && videoTime == -1));
+
+
+      if ((aType == TrackInfo::kAudioTrack && audioTime == -1) ||
+          (aType == TrackInfo::kVideoTrack && videoTime == -1)) {
+        // We don't have timestamps for all active tracks...
+        if (pageOffset == startOffset + startLength &&
+            pageOffset + pageLength >= endOffset) {
+          // We read the entire interval without finding timestamps for all
+          // active tracks. We know the interval start offset is before the seek
+          // target, and the interval end is after the seek target, and we can't
+          // terminate inside the interval, so we terminate the seek at the
+          // start of the interval.
+          interval = 0;
+          break;
+        }
+
+        // We should backoff; cause the guess to back off from the end, so
+        // that we've got more room to capture.
+        mustBackoff = true;
+        continue;
+      }
+
+      // We've found appropriate time stamps here. Proceed to bisect
+      // the search space.
+      granuleTime = aType == TrackInfo::kAudioTrack ? audioTime : videoTime;
+      NS_ASSERTION(granuleTime > 0, "Must get a granuletime");
+      break;
+    } // End of "until we determine time at guess offset" loop.
+
+    if (interval == 0) {
+      // Seek termination condition; we've found the page boundary of the
+      // last page before the target, and the first page after the target.
+      SEEK_LOG(LogLevel::Debug, ("Terminating seek at offset=%lld", startOffset));
+      NS_ASSERTION(startTime < aTarget, "Start time must always be less than target");
+      res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, startOffset);
+      NS_ENSURE_SUCCESS(res,res);
+      if (NS_FAILED(Reset(aType))) {
+        return NS_ERROR_FAILURE;
+      }
+      break;
+    }
+
+    SEEK_LOG(LogLevel::Debug, ("Time at offset %lld is %lld", guess, granuleTime));
+    if (granuleTime < seekTarget && granuleTime > seekLowerBound) {
+      // We're within the fuzzy region in which we want to terminate the search.
+      res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, pageOffset);
+      NS_ENSURE_SUCCESS(res,res);
+      if (NS_FAILED(Reset(aType))) {
+        return NS_ERROR_FAILURE;
+      }
+      SEEK_LOG(LogLevel::Debug, ("Terminating seek at offset=%lld", pageOffset));
+      break;
+    }
+
+    if (granuleTime >= seekTarget) {
+      // We've landed after the seek target.
+      NS_ASSERTION(pageOffset < endOffset, "offset_end must decrease");
+      endOffset = pageOffset;
+      endTime = granuleTime;
+    } else if (granuleTime < seekTarget) {
+      // Landed before seek target.
+      NS_ASSERTION(pageOffset >= startOffset + startLength,
+        "Bisection point should be at or after end of first page in interval");
+      startOffset = pageOffset;
+      startLength = pageLength;
+      startTime = granuleTime;
+    }
+    NS_ASSERTION(startTime <= seekTarget, "Must be before seek target");
+    NS_ASSERTION(endTime >= seekTarget, "End must be after seek target");
+  }
+
+  SEEK_LOG(LogLevel::Debug, ("Seek complete in %d bisections.", hops));
+
+  return NS_OK;
+}
+
+#undef OGG_DEBUG
+#undef SEEK_DEBUG
+} // namespace mozilla