path: root/dom/media/webm/WebMDemuxer.cpp

/* -*- 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 "MediaResource.h"
#ifdef MOZ_AV1
#  include "AOMDecoder.h"
#endif
#include "VPXDecoder.h"
#include "WebMDemuxer.h"
#include "WebMBufferedParser.h"
#include "gfx2DGlue.h"
#include "gfxUtils.h"
#include "mozilla/EndianUtils.h"
#include "mozilla/SharedThreadPool.h"
#include "MediaDataDemuxer.h"
#include "nsAutoRef.h"
#include "NesteggPacketHolder.h"
#include "XiphExtradata.h"
#include "prprf.h"  // leaving it for PR_vsnprintf()
#include "mozilla/IntegerPrintfMacros.h"
#include "mozilla/Sprintf.h"
#include "VideoUtils.h"

#include <algorithm>
#include <numeric>
#include <stdint.h>

#define WEBM_DEBUG(arg, ...)                                          \
  DDMOZ_LOG(gMediaDemuxerLog, mozilla::LogLevel::Debug, "::%s: " arg, \
            __func__, ##__VA_ARGS__)
extern mozilla::LazyLogModule gMediaDemuxerLog;

namespace mozilla {

using namespace gfx;
using media::TimeUnit;

LazyLogModule gNesteggLog("Nestegg");

// How far ahead will we look when searching future keyframe. In microseconds.
// This value is based on what appears to be a reasonable value as most webm
// files encountered appear to have keyframes located < 4s.
#define MAX_LOOK_AHEAD 10000000

// Functions for reading and seeking using WebMDemuxer required for
// nestegg_io. The 'user data' passed to these functions is the
// demuxer.
static int webmdemux_read(void* aBuffer, size_t aLength, void* aUserData) {
  MOZ_ASSERT(aUserData);
  MOZ_ASSERT(aLength < UINT32_MAX);
  WebMDemuxer::NestEggContext* context =
      reinterpret_cast<WebMDemuxer::NestEggContext*>(aUserData);
  uint32_t count = aLength;
  if (context->IsMediaSource()) {
    int64_t length = context->GetEndDataOffset();
    int64_t position = context->GetResource()->Tell();
    MOZ_ASSERT(position <= context->GetResource()->GetLength());
    MOZ_ASSERT(position <= length);
    if (length >= 0 && count + position > length) {
      count = length - position;
    }
    MOZ_ASSERT(count <= aLength);
  }
  uint32_t bytes = 0;
  nsresult rv =
      context->GetResource()->Read(static_cast<char*>(aBuffer), count, &bytes);
  bool eof = bytes < aLength;
  return NS_FAILED(rv) ? -1 : eof ? 0 : 1;
}

static int webmdemux_seek(int64_t aOffset, int aWhence, void* aUserData) {
  MOZ_ASSERT(aUserData);
  WebMDemuxer::NestEggContext* context =
      reinterpret_cast<WebMDemuxer::NestEggContext*>(aUserData);
  nsresult rv = context->GetResource()->Seek(aWhence, aOffset);
  return NS_SUCCEEDED(rv) ? 0 : -1;
}

static int64_t webmdemux_tell(void* aUserData) {
  MOZ_ASSERT(aUserData);
  WebMDemuxer::NestEggContext* context =
      reinterpret_cast<WebMDemuxer::NestEggContext*>(aUserData);
  return context->GetResource()->Tell();
}

static void webmdemux_log(nestegg* aContext, unsigned int aSeverity,
                          char const* aFormat, ...) {
  if (!MOZ_LOG_TEST(gNesteggLog, LogLevel::Debug)) {
    return;
  }

  va_list args;
  char msg[256];
  const char* sevStr;

  switch (aSeverity) {
    case NESTEGG_LOG_DEBUG:
      sevStr = "DBG";
      break;
    case NESTEGG_LOG_INFO:
      sevStr = "INF";
      break;
    case NESTEGG_LOG_WARNING:
      sevStr = "WRN";
      break;
    case NESTEGG_LOG_ERROR:
      sevStr = "ERR";
      break;
    case NESTEGG_LOG_CRITICAL:
      sevStr = "CRT";
      break;
    default:
      sevStr = "UNK";
      break;
  }

  va_start(args, aFormat);

  SprintfLiteral(msg, "%p [Nestegg-%s] ", aContext, sevStr);
  PR_vsnprintf(msg + strlen(msg), sizeof(msg) - strlen(msg), aFormat, args);
  MOZ_LOG(gNesteggLog, LogLevel::Debug, ("%s", msg));

  va_end(args);
}

WebMDemuxer::NestEggContext::~NestEggContext() {
  if (mContext) {
    nestegg_destroy(mContext);
  }
}

int WebMDemuxer::NestEggContext::Init() {
  nestegg_io io;
  io.read = webmdemux_read;
  io.seek = webmdemux_seek;
  io.tell = webmdemux_tell;
  io.userdata = this;

  // While reading the metadata, we do not really care about which nestegg
  // context is being used so long that they are both initialised.
  // For reading the metadata however, we will use mVideoContext.
  return nestegg_init(&mContext, io, &webmdemux_log,
                      mParent->IsMediaSource() ? mResource.GetLength() : -1);
}

WebMDemuxer::WebMDemuxer(MediaResource* aResource)
    : WebMDemuxer(aResource, false) {}

WebMDemuxer::WebMDemuxer(MediaResource* aResource, bool aIsMediaSource)
    : mVideoContext(this, aResource),
      mAudioContext(this, aResource),
      mBufferedState(nullptr),
      mInitData(nullptr),
      mVideoTrack(0),
      mAudioTrack(0),
      mSeekPreroll(0),
      mAudioCodec(-1),
      mVideoCodec(-1),
      mHasVideo(false),
      mHasAudio(false),
      mNeedReIndex(true),
      mLastWebMBlockOffset(-1),
      mIsMediaSource(aIsMediaSource) {
  DDLINKCHILD("resource", aResource);
  // Audio/video contexts hold a MediaResourceIndex.
  DDLINKCHILD("video context", mVideoContext.GetResource());
  DDLINKCHILD("audio context", mAudioContext.GetResource());
}

WebMDemuxer::~WebMDemuxer() {
  Reset(TrackInfo::kVideoTrack);
  Reset(TrackInfo::kAudioTrack);
}

RefPtr<WebMDemuxer::InitPromise> WebMDemuxer::Init() {
  InitBufferedState();

  if (NS_FAILED(ReadMetadata())) {
    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__);
}

void WebMDemuxer::InitBufferedState() {
  MOZ_ASSERT(!mBufferedState);
  mBufferedState = new WebMBufferedState;
}

uint32_t WebMDemuxer::GetNumberTracks(TrackInfo::TrackType aType) const {
  switch (aType) {
    case TrackInfo::kAudioTrack:
      return mHasAudio ? 1 : 0;
    case TrackInfo::kVideoTrack:
      return mHasVideo ? 1 : 0;
    default:
      return 0;
  }
}

UniquePtr<TrackInfo> WebMDemuxer::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> WebMDemuxer::GetTrackDemuxer(
    TrackInfo::TrackType aType, uint32_t aTrackNumber) {
  if (GetNumberTracks(aType) <= aTrackNumber) {
    return nullptr;
  }
  RefPtr<WebMTrackDemuxer> e = new WebMTrackDemuxer(this, aType, aTrackNumber);
  DDLINKCHILD("track demuxer", e.get());
  mDemuxers.AppendElement(e);

  return e.forget();
}

void WebMDemuxer::Reset(TrackInfo::TrackType aType) {
  mProcessedDiscardPadding = false;
  if (aType == TrackInfo::kVideoTrack) {
    mVideoPackets.Reset();
  } else {
    mAudioPackets.Reset();
  }
}

nsresult WebMDemuxer::ReadMetadata() {
  int r = mVideoContext.Init();
  if (r == -1) {
    WEBM_DEBUG("mVideoContext::Init failure");
    return NS_ERROR_FAILURE;
  }
  if (mAudioContext.Init() == -1) {
    WEBM_DEBUG("mAudioContext::Init failure");
    return NS_ERROR_FAILURE;
  }

  // For reading the metadata we can only use the video resource/context.
  MediaResourceIndex& resource = Resource(TrackInfo::kVideoTrack);
  nestegg* context = Context(TrackInfo::kVideoTrack);

  {
    // Check how much data nestegg read and force feed it to BufferedState.
    RefPtr<MediaByteBuffer> buffer = resource.MediaReadAt(0, resource.Tell());
    if (!buffer) {
      WEBM_DEBUG("resource.MediaReadAt error");
      return NS_ERROR_FAILURE;
    }
    mBufferedState->NotifyDataArrived(buffer->Elements(), buffer->Length(), 0);
    if (mBufferedState->GetInitEndOffset() < 0) {
      WEBM_DEBUG("Couldn't find init end");
      return NS_ERROR_FAILURE;
    }
    MOZ_ASSERT(mBufferedState->GetInitEndOffset() <= resource.Tell());
  }
  mInitData = resource.MediaReadAt(0, mBufferedState->GetInitEndOffset());
  if (!mInitData ||
      mInitData->Length() != size_t(mBufferedState->GetInitEndOffset())) {
    WEBM_DEBUG("Couldn't read init data");
    return NS_ERROR_FAILURE;
  }

  unsigned int ntracks = 0;
  r = nestegg_track_count(context, &ntracks);
  if (r == -1) {
    WEBM_DEBUG("nestegg_track_count error");
    return NS_ERROR_FAILURE;
  }

  for (unsigned int track = 0; track < ntracks; ++track) {
    int id = nestegg_track_codec_id(context, track);
    if (id == -1) {
      WEBM_DEBUG("nestegg_track_codec_id error");
      return NS_ERROR_FAILURE;
    }
    int type = nestegg_track_type(context, track);
    if (type == NESTEGG_TRACK_VIDEO && !mHasVideo) {
      nestegg_video_params params;
      r = nestegg_track_video_params(context, track, &params);
      if (r == -1) {
        WEBM_DEBUG("nestegg_track_video_params error");
        return NS_ERROR_FAILURE;
      }
      mVideoCodec = nestegg_track_codec_id(context, track);
      switch (mVideoCodec) {
        case NESTEGG_CODEC_VP8:
          mInfo.mVideo.mMimeType = "video/vp8";
          break;
        case NESTEGG_CODEC_VP9:
          mInfo.mVideo.mMimeType = "video/vp9";
          break;
        case NESTEGG_CODEC_AV1:
          mInfo.mVideo.mMimeType = "video/av1";
          break;
        default:
          NS_WARNING("Unknown WebM video codec");
          return NS_ERROR_FAILURE;
      }

      mInfo.mVideo.mColorPrimaries = gfxUtils::CicpToColorPrimaries(
          static_cast<gfx::CICP::ColourPrimaries>(params.primaries),
          gMediaDemuxerLog);

      // For VPX, this is our only chance to capture the transfer
      // characteristics, which we can't get from a VPX bitstream later.
      // We only need this value if the video is using the BT2020
      // colorspace, which will be determined on a per-frame basis later.
      mInfo.mVideo.mTransferFunction = gfxUtils::CicpToTransferFunction(
          static_cast<gfx::CICP::TransferCharacteristics>(
              params.transfer_characteristics));

      // Picture region, taking into account cropping, before scaling
      // to the display size.
      unsigned int cropH = params.crop_right + params.crop_left;
      unsigned int cropV = params.crop_bottom + params.crop_top;
      gfx::IntRect pictureRect(params.crop_left, params.crop_top,
                               params.width - cropH, params.height - cropV);

      // If the cropping data appears invalid then use the frame data
      if (pictureRect.width <= 0 || pictureRect.height <= 0 ||
          pictureRect.x < 0 || pictureRect.y < 0) {
        pictureRect.x = 0;
        pictureRect.y = 0;
        pictureRect.width = params.width;
        pictureRect.height = params.height;
      }

      // Validate the container-reported frame and pictureRect sizes. This
      // ensures that our video frame creation code doesn't overflow.
      gfx::IntSize displaySize(params.display_width, params.display_height);
      gfx::IntSize frameSize(params.width, params.height);
      if (!IsValidVideoRegion(frameSize, pictureRect, displaySize)) {
        // Video track's frame sizes will overflow. Ignore the video track.
        continue;
      }

      mVideoTrack = track;
      mHasVideo = true;

      mInfo.mVideo.mDisplay = displaySize;
      mInfo.mVideo.mImage = frameSize;
      mInfo.mVideo.SetImageRect(pictureRect);
      mInfo.mVideo.SetAlpha(params.alpha_mode);

      switch (params.stereo_mode) {
        case NESTEGG_VIDEO_MONO:
          mInfo.mVideo.mStereoMode = StereoMode::MONO;
          break;
        case NESTEGG_VIDEO_STEREO_LEFT_RIGHT:
          mInfo.mVideo.mStereoMode = StereoMode::LEFT_RIGHT;
          break;
        case NESTEGG_VIDEO_STEREO_BOTTOM_TOP:
          mInfo.mVideo.mStereoMode = StereoMode::BOTTOM_TOP;
          break;
        case NESTEGG_VIDEO_STEREO_TOP_BOTTOM:
          mInfo.mVideo.mStereoMode = StereoMode::TOP_BOTTOM;
          break;
        case NESTEGG_VIDEO_STEREO_RIGHT_LEFT:
          mInfo.mVideo.mStereoMode = StereoMode::RIGHT_LEFT;
          break;
      }
      uint64_t duration = 0;
      r = nestegg_duration(context, &duration);
      if (!r) {
        mInfo.mVideo.mDuration = TimeUnit::FromNanoseconds(duration);
      }
      WEBM_DEBUG("stream duration: %lf\n", mInfo.mVideo.mDuration.ToSeconds());
      mInfo.mVideo.mCrypto = GetTrackCrypto(TrackInfo::kVideoTrack, track);
      if (mInfo.mVideo.mCrypto.IsEncrypted()) {
        MOZ_ASSERT(mInfo.mVideo.mCrypto.mCryptoScheme == CryptoScheme::Cenc,
                   "WebM should only use cenc scheme");
        mCrypto.AddInitData(u"webm"_ns, mInfo.mVideo.mCrypto.mKeyId);
      }
    } else if (type == NESTEGG_TRACK_AUDIO && !mHasAudio) {
      nestegg_audio_params params;
      r = nestegg_track_audio_params(context, track, &params);
      if (r == -1) {
        WEBM_DEBUG("nestegg_track_audio_params error");
        return NS_ERROR_FAILURE;
      }
      if (params.rate >
              static_cast<decltype(params.rate)>(AudioInfo::MAX_RATE) ||
          params.rate <= static_cast<decltype(params.rate)>(0) ||
          params.channels > AudioConfig::ChannelLayout::MAX_CHANNELS) {
        WEBM_DEBUG("Invalid audio param rate: %lf channel count: %d",
                   params.rate, params.channels);
        return NS_ERROR_DOM_MEDIA_METADATA_ERR;
      }

      mAudioTrack = track;
      mHasAudio = true;
      mAudioCodec = nestegg_track_codec_id(context, track);
      if (mAudioCodec == NESTEGG_CODEC_VORBIS) {
        mInfo.mAudio.mCodecSpecificConfig =
            AudioCodecSpecificVariant{VorbisCodecSpecificData{}};
        mInfo.mAudio.mMimeType = "audio/vorbis";
      } else if (mAudioCodec == NESTEGG_CODEC_OPUS) {
        uint64_t codecDelayUs = params.codec_delay / 1000;
        mInfo.mAudio.mMimeType = "audio/opus";
        OpusCodecSpecificData opusCodecSpecificData;
        opusCodecSpecificData.mContainerCodecDelayFrames =
            AssertedCast<int64_t>(USECS_PER_S * codecDelayUs / 48000);
        WEBM_DEBUG("Preroll for Opus: %" PRIu64 " frames",
                   opusCodecSpecificData.mContainerCodecDelayFrames);
        mInfo.mAudio.mCodecSpecificConfig =
            AudioCodecSpecificVariant{std::move(opusCodecSpecificData)};
      }
      mSeekPreroll = params.seek_preroll;
      mInfo.mAudio.mRate = AssertedCast<uint32_t>(params.rate);
      mInfo.mAudio.mChannels = params.channels;

      unsigned int nheaders = 0;
      r = nestegg_track_codec_data_count(context, track, &nheaders);
      if (r == -1) {
        WEBM_DEBUG("nestegg_track_codec_data_count error");
        return NS_ERROR_FAILURE;
      }

      AutoTArray<const unsigned char*, 4> headers;
      AutoTArray<size_t, 4> headerLens;
      for (uint32_t header = 0; header < nheaders; ++header) {
        unsigned char* data = 0;
        size_t length = 0;
        r = nestegg_track_codec_data(context, track, header, &data, &length);
        if (r == -1) {
          WEBM_DEBUG("nestegg_track_codec_data error");
          return NS_ERROR_FAILURE;
        }
        headers.AppendElement(data);
        headerLens.AppendElement(length);
      }

      // Vorbis has 3 headers, convert to Xiph extradata format to send them to
      // the demuxer.
      // TODO: This is already the format WebM stores them in. Would be nice
      // to avoid having libnestegg split them only for us to pack them again,
      // but libnestegg does not give us an API to access this data directly.
      RefPtr<MediaByteBuffer> audioCodecSpecificBlob =
          GetAudioCodecSpecificBlob(mInfo.mAudio.mCodecSpecificConfig);
      if (nheaders > 1) {
        if (!XiphHeadersToExtradata(audioCodecSpecificBlob, headers,
                                    headerLens)) {
          WEBM_DEBUG("Couldn't parse Xiph headers");
          return NS_ERROR_FAILURE;
        }
      } else {
        audioCodecSpecificBlob->AppendElements(headers[0], headerLens[0]);
      }
      uint64_t duration = 0;
      r = nestegg_duration(context, &duration);
      if (!r) {
        mInfo.mAudio.mDuration = TimeUnit::FromNanoseconds(duration);
        WEBM_DEBUG("audio track duration: %lf",
                   mInfo.mAudio.mDuration.ToSeconds());
      }
      mInfo.mAudio.mCrypto = GetTrackCrypto(TrackInfo::kAudioTrack, track);
      if (mInfo.mAudio.mCrypto.IsEncrypted()) {
        MOZ_ASSERT(mInfo.mAudio.mCrypto.mCryptoScheme == CryptoScheme::Cenc,
                   "WebM should only use cenc scheme");
        mCrypto.AddInitData(u"webm"_ns, mInfo.mAudio.mCrypto.mKeyId);
      }
    }
  }
  WEBM_DEBUG("Read metadata OK");
  return NS_OK;
}

bool WebMDemuxer::IsSeekable() const {
  return Context(TrackInfo::kVideoTrack) &&
         nestegg_has_cues(Context(TrackInfo::kVideoTrack));
}

bool WebMDemuxer::IsSeekableOnlyInBufferedRanges() const {
  return Context(TrackInfo::kVideoTrack) &&
         !nestegg_has_cues(Context(TrackInfo::kVideoTrack));
}

void WebMDemuxer::EnsureUpToDateIndex() {
  if (!mNeedReIndex || !mInitData) {
    return;
  }
  AutoPinned<MediaResource> resource(
      Resource(TrackInfo::kVideoTrack).GetResource());
  MediaByteRangeSet byteRanges;
  nsresult rv = resource->GetCachedRanges(byteRanges);
  if (NS_FAILED(rv) || byteRanges.IsEmpty()) {
    return;
  }
  mBufferedState->UpdateIndex(byteRanges, resource);

  mNeedReIndex = false;

  if (!mIsMediaSource) {
    return;
  }
  mLastWebMBlockOffset = mBufferedState->GetLastBlockOffset();
  MOZ_ASSERT(mLastWebMBlockOffset <= resource->GetLength());
}

void WebMDemuxer::NotifyDataArrived() {
  WEBM_DEBUG("");
  mNeedReIndex = true;
}

void WebMDemuxer::NotifyDataRemoved() {
  mBufferedState->Reset();
  if (mInitData) {
    mBufferedState->NotifyDataArrived(mInitData->Elements(),
                                      mInitData->Length(), 0);
  }
  mNeedReIndex = true;
}

UniquePtr<EncryptionInfo> WebMDemuxer::GetCrypto() {
  return mCrypto.IsEncrypted() ? MakeUnique<EncryptionInfo>(mCrypto) : nullptr;
}

CryptoTrack WebMDemuxer::GetTrackCrypto(TrackInfo::TrackType aType,
                                        size_t aTrackNumber) {
  const int WEBM_IV_SIZE = 16;
  const unsigned char* contentEncKeyId;
  size_t contentEncKeyIdLength;
  CryptoTrack crypto;
  nestegg* context = Context(aType);

  int r = nestegg_track_content_enc_key_id(
      context, aTrackNumber, &contentEncKeyId, &contentEncKeyIdLength);

  if (r == -1) {
    WEBM_DEBUG("nestegg_track_content_enc_key_id failed r=%d", r);
    return crypto;
  }

  uint32_t i;
  nsTArray<uint8_t> initData;
  for (i = 0; i < contentEncKeyIdLength; i++) {
    initData.AppendElement(contentEncKeyId[i]);
  }

  if (!initData.IsEmpty()) {
    // Webm only uses a cenc style scheme.
    crypto.mCryptoScheme = CryptoScheme::Cenc;
    crypto.mIVSize = WEBM_IV_SIZE;
    crypto.mKeyId = std::move(initData);
  }

  return crypto;
}

nsresult WebMDemuxer::GetNextPacket(TrackInfo::TrackType aType,
                                    MediaRawDataQueue* aSamples) {
  if (mIsMediaSource) {
    // To ensure mLastWebMBlockOffset is properly up to date.
    EnsureUpToDateIndex();
  }

  RefPtr<NesteggPacketHolder> holder;
  nsresult rv = NextPacket(aType, holder);

  if (NS_FAILED(rv)) {
    return rv;
  }

  int r = 0;
  unsigned int count = 0;
  r = nestegg_packet_count(holder->Packet(), &count);
  if (r == -1) {
    WEBM_DEBUG("nestegg_packet_count: error");
    return NS_ERROR_DOM_MEDIA_DEMUXER_ERR;
  }
  int64_t tstamp = holder->Timestamp();
  int64_t duration = holder->Duration();

  // The end time of this frame is the start time of the next frame. Fetch
  // the timestamp of the next packet for this track.  If we've reached the
  // end of the resource, use the file's duration as the end time of this
  // video frame.
  RefPtr<NesteggPacketHolder> next_holder;
  rv = NextPacket(aType, next_holder);
  if (NS_FAILED(rv) && rv != NS_ERROR_DOM_MEDIA_END_OF_STREAM) {
    WEBM_DEBUG("NextPacket: error");
    return rv;
  }

  int64_t next_tstamp = INT64_MIN;
  auto calculateNextTimestamp = [&](auto&& pushPacket, auto&& lastFrameTime,
                                    int64_t trackEndTime) {
    if (next_holder) {
      next_tstamp = next_holder->Timestamp();
      (this->*pushPacket)(next_holder);
    } else if (duration >= 0) {
      next_tstamp = tstamp + duration;
    } else if (lastFrameTime.isSome()) {
      next_tstamp = tstamp + (tstamp - lastFrameTime.ref());
    } else if (mIsMediaSource) {
      (this->*pushPacket)(holder);
    } else {
      // If we can't get frame's duration, it means either we need to wait for
      // more data for MSE case or this is the last frame for file resource
      // case.
      if (tstamp > trackEndTime) {
        // This shouldn't happen, but some muxers give incorrect durations to
        // segments, then have samples appear beyond those durations.
        WEBM_DEBUG("Found tstamp=%" PRIi64 " > trackEndTime=%" PRIi64
                   " while calculating next timestamp! Indicates a bad mux! "
                   "Will use tstamp value.",
                   tstamp, trackEndTime);
      }
      next_tstamp = std::max<int64_t>(tstamp, trackEndTime);
    }
    lastFrameTime = Some(tstamp);
  };

  if (aType == TrackInfo::kAudioTrack) {
    calculateNextTimestamp(&WebMDemuxer::PushAudioPacket, mLastAudioFrameTime,
                           mInfo.mAudio.mDuration.ToMicroseconds());
  } else {
    calculateNextTimestamp(&WebMDemuxer::PushVideoPacket, mLastVideoFrameTime,
                           mInfo.mVideo.mDuration.ToMicroseconds());
  }

  if (mIsMediaSource && next_tstamp == INT64_MIN) {
    WEBM_DEBUG("WebM is a media source, and next timestamp computation filed.");
    return NS_ERROR_DOM_MEDIA_END_OF_STREAM;
  }

  int64_t discardPadding = 0;
  if (aType == TrackInfo::kAudioTrack) {
    (void)nestegg_packet_discard_padding(holder->Packet(), &discardPadding);
  }

  int packetEncryption = nestegg_packet_encryption(holder->Packet());

  for (uint32_t i = 0; i < count; ++i) {
    unsigned char* data = nullptr;
    size_t length;
    r = nestegg_packet_data(holder->Packet(), i, &data, &length);
    if (r == -1) {
      WEBM_DEBUG("nestegg_packet_data failed r=%d", r);
      return NS_ERROR_DOM_MEDIA_DEMUXER_ERR;
    }
    unsigned char* alphaData = nullptr;
    size_t alphaLength = 0;
    // Check packets for alpha information if file has declared alpha frames
    // may be present.
    if (mInfo.mVideo.HasAlpha()) {
      r = nestegg_packet_additional_data(holder->Packet(), 1, &alphaData,
                                         &alphaLength);
      if (r == -1) {
        WEBM_DEBUG(
            "nestegg_packet_additional_data failed to retrieve alpha data r=%d",
            r);
      }
    }
    bool isKeyframe = false;
    if (aType == TrackInfo::kAudioTrack) {
      isKeyframe = true;
    } else if (aType == TrackInfo::kVideoTrack) {
      if (packetEncryption == NESTEGG_PACKET_HAS_SIGNAL_BYTE_ENCRYPTED ||
          packetEncryption == NESTEGG_PACKET_HAS_SIGNAL_BYTE_PARTITIONED) {
        // Packet is encrypted, can't peek, use packet info
        isKeyframe = nestegg_packet_has_keyframe(holder->Packet()) ==
                     NESTEGG_PACKET_HAS_KEYFRAME_TRUE;
      } else {
        MOZ_ASSERT(
            packetEncryption == NESTEGG_PACKET_HAS_SIGNAL_BYTE_UNENCRYPTED ||
                packetEncryption == NESTEGG_PACKET_HAS_SIGNAL_BYTE_FALSE,
            "Unencrypted packet expected");
        auto sample = Span(data, length);
        auto alphaSample = Span(alphaData, alphaLength);

        switch (mVideoCodec) {
          case NESTEGG_CODEC_VP8:
            isKeyframe = VPXDecoder::IsKeyframe(sample, VPXDecoder::Codec::VP8);
            if (isKeyframe && alphaLength) {
              isKeyframe =
                  VPXDecoder::IsKeyframe(alphaSample, VPXDecoder::Codec::VP8);
            }
            break;
          case NESTEGG_CODEC_VP9:
            isKeyframe = VPXDecoder::IsKeyframe(sample, VPXDecoder::Codec::VP9);
            if (isKeyframe && alphaLength) {
              isKeyframe =
                  VPXDecoder::IsKeyframe(alphaSample, VPXDecoder::Codec::VP9);
            }
            break;
#ifdef MOZ_AV1
          case NESTEGG_CODEC_AV1:
            isKeyframe = AOMDecoder::IsKeyframe(sample);
            if (isKeyframe && alphaLength) {
              isKeyframe = AOMDecoder::IsKeyframe(alphaSample);
            }
            break;
#endif
          default:
            NS_WARNING("Cannot detect keyframes in unknown WebM video codec");
            return NS_ERROR_FAILURE;
        }
      }
    }

    WEBM_DEBUG("push sample tstamp: %" PRId64 " next_tstamp: %" PRId64
               " length: %zu kf: %d",
               tstamp, next_tstamp, length, isKeyframe);
    RefPtr<MediaRawData> sample;
    if (mInfo.mVideo.HasAlpha() && alphaLength != 0) {
      sample = new MediaRawData(data, length, alphaData, alphaLength);
      if ((length && !sample->Data()) ||
          (alphaLength && !sample->AlphaData())) {
        WEBM_DEBUG("Couldn't allocate MediaRawData: OOM");
        return NS_ERROR_OUT_OF_MEMORY;
      }
    } else {
      sample = new MediaRawData(data, length);
      if (length && !sample->Data()) {
        WEBM_DEBUG("Couldn't allocate MediaRawData: OOM");
        return NS_ERROR_OUT_OF_MEMORY;
      }
    }
    sample->mTimecode = TimeUnit::FromMicroseconds(tstamp);
    sample->mTime = TimeUnit::FromMicroseconds(tstamp);
    if (next_tstamp > tstamp) {
      sample->mDuration = TimeUnit::FromMicroseconds(next_tstamp - tstamp);
    }
    sample->mOffset = holder->Offset();
    sample->mKeyframe = isKeyframe;
    if (discardPadding && i == count - 1) {
      sample->mOriginalPresentationWindow =
          Some(media::TimeInterval{sample->mTime, sample->GetEndTime()});
      if (discardPadding < 0) {
        // This will ensure decoding will error out, and the file is rejected.
        sample->mDuration = TimeUnit::Invalid();
      } else {
        TimeUnit padding = TimeUnit::FromNanoseconds(discardPadding);
        if (padding > sample->mDuration || mProcessedDiscardPadding) {
          WEBM_DEBUG(
              "Padding frames larger than packet size, flagging the packet for "
              "error (padding: %s, duration: %s, already processed: %s)",
              padding.ToString().get(), sample->mDuration.ToString().get(),
              mProcessedDiscardPadding ? "true" : "false");
          sample->mDuration = TimeUnit::Invalid();
        } else {
          sample->mDuration -= padding;
        }
      }
      mProcessedDiscardPadding = true;
    }

    if (packetEncryption == NESTEGG_PACKET_HAS_SIGNAL_BYTE_ENCRYPTED ||
        packetEncryption == NESTEGG_PACKET_HAS_SIGNAL_BYTE_PARTITIONED) {
      UniquePtr<MediaRawDataWriter> writer(sample->CreateWriter());
      unsigned char const* iv;
      size_t ivLength;
      nestegg_packet_iv(holder->Packet(), &iv, &ivLength);
      writer->mCrypto.mCryptoScheme = CryptoScheme::Cenc;
      writer->mCrypto.mIVSize = ivLength;
      if (ivLength == 0) {
        // Frame is not encrypted. This shouldn't happen as it means the
        // encryption bit is set on a frame with no IV, but we gracefully
        // handle incase.
        MOZ_ASSERT_UNREACHABLE(
            "Unencrypted packets should not have the encryption bit set!");
        WEBM_DEBUG("Unencrypted packet with encryption bit set");
        writer->mCrypto.mPlainSizes.AppendElement(length);
        writer->mCrypto.mEncryptedSizes.AppendElement(0);
      } else {
        // Frame is encrypted
        writer->mCrypto.mIV.AppendElements(iv, 8);
        // Iv from a sample is 64 bits, must be padded with 64 bits more 0s
        // in compliance with spec
        for (uint32_t i = 0; i < 8; i++) {
          writer->mCrypto.mIV.AppendElement(0);
        }

        if (packetEncryption == NESTEGG_PACKET_HAS_SIGNAL_BYTE_ENCRYPTED) {
          writer->mCrypto.mPlainSizes.AppendElement(0);
          writer->mCrypto.mEncryptedSizes.AppendElement(length);
        } else if (packetEncryption ==
                   NESTEGG_PACKET_HAS_SIGNAL_BYTE_PARTITIONED) {
          uint8_t numPartitions = 0;
          const uint32_t* partitions = NULL;
          nestegg_packet_offsets(holder->Packet(), &partitions, &numPartitions);

          // WebM stores a list of 'partitions' in the data, which alternate
          // clear, encrypted. The data in the first partition is always clear.
          // So, and sample might look as follows:
          // 00|XXXX|000|XX, where | represents a partition, 0 a clear byte and
          // X an encrypted byte. If the first bytes in sample are unencrypted,
          // the first partition will be at zero |XXXX|000|XX.
          //
          // As GMP expects the lengths of the clear and encrypted chunks of
          // data, we calculate these from the difference between the last two
          // partitions.
          uint32_t lastOffset = 0;
          bool encrypted = false;

          for (uint8_t i = 0; i < numPartitions; i++) {
            uint32_t partition = partitions[i];
            uint32_t currentLength = partition - lastOffset;

            if (encrypted) {
              writer->mCrypto.mEncryptedSizes.AppendElement(currentLength);
            } else {
              writer->mCrypto.mPlainSizes.AppendElement(currentLength);
            }

            encrypted = !encrypted;
            lastOffset = partition;

            MOZ_ASSERT(lastOffset <= length);
          }

          // Add the data between the last offset and the end of the data.
          // 000|XXX|000
          //        ^---^
          if (encrypted) {
            writer->mCrypto.mEncryptedSizes.AppendElement(length - lastOffset);
          } else {
            writer->mCrypto.mPlainSizes.AppendElement(length - lastOffset);
          }

          // Make sure we have an equal number of encrypted and plain sizes (GMP
          // expects this). This simple check is sufficient as there are two
          // possible cases at this point:
          // 1. The number of samples are even (so we don't need to do anything)
          // 2. There is one more clear sample than encrypted samples, so add a
          // zero length encrypted chunk.
          // There can never be more encrypted partitions than clear partitions
          // due to the alternating structure of the WebM samples and the
          // restriction that the first chunk is always clear.
          if (numPartitions % 2 == 0) {
            writer->mCrypto.mEncryptedSizes.AppendElement(0);
          }

          // Assert that the lengths of the encrypted and plain samples add to
          // the length of the data.
          MOZ_ASSERT(
              ((size_t)(std::accumulate(writer->mCrypto.mPlainSizes.begin(),
                                        writer->mCrypto.mPlainSizes.end(), 0) +
                        std::accumulate(writer->mCrypto.mEncryptedSizes.begin(),
                                        writer->mCrypto.mEncryptedSizes.end(),
                                        0)) == length));
        }
      }
    }
    aSamples->Push(sample);
  }
  return NS_OK;
}

nsresult WebMDemuxer::NextPacket(TrackInfo::TrackType aType,
                                 RefPtr<NesteggPacketHolder>& aPacket) {
  bool isVideo = aType == TrackInfo::kVideoTrack;

  // Flag to indicate that we do need to playback these types of
  // packets.
  bool hasType = isVideo ? mHasVideo : mHasAudio;

  if (!hasType) {
    WEBM_DEBUG("No media type found");
    return NS_ERROR_DOM_MEDIA_DEMUXER_ERR;
  }

  // The packet queue for the type that we are interested in.
  WebMPacketQueue& packets = isVideo ? mVideoPackets : mAudioPackets;

  if (packets.GetSize() > 0) {
    aPacket = packets.PopFront();
    return NS_OK;
  }

  // Track we are interested in
  uint32_t ourTrack = isVideo ? mVideoTrack : mAudioTrack;

  do {
    RefPtr<NesteggPacketHolder> holder;
    nsresult rv = DemuxPacket(aType, holder);
    if (NS_FAILED(rv)) {
      return rv;
    }
    if (!holder) {
      WEBM_DEBUG("Couldn't demux packet");
      return NS_ERROR_DOM_MEDIA_DEMUXER_ERR;
    }

    if (ourTrack == holder->Track()) {
      aPacket = holder;
      return NS_OK;
    }
  } while (true);
}

nsresult WebMDemuxer::DemuxPacket(TrackInfo::TrackType aType,
                                  RefPtr<NesteggPacketHolder>& aPacket) {
  nestegg_packet* packet;
  int r = nestegg_read_packet(Context(aType), &packet);
  if (r == 0) {
    nestegg_read_reset(Context(aType));
    WEBM_DEBUG("EOS");
    return NS_ERROR_DOM_MEDIA_END_OF_STREAM;
  } else if (r < 0) {
    WEBM_DEBUG("nestegg_read_packet: error");
    return NS_ERROR_DOM_MEDIA_DEMUXER_ERR;
  }

  unsigned int track = 0;
  r = nestegg_packet_track(packet, &track);
  if (r == -1) {
    WEBM_DEBUG("nestegg_packet_track: error");
    return NS_ERROR_DOM_MEDIA_DEMUXER_ERR;
  }

  int64_t offset = Resource(aType).Tell();
  RefPtr<NesteggPacketHolder> holder = new NesteggPacketHolder();
  if (!holder->Init(packet, offset, track, false)) {
    WEBM_DEBUG("NesteggPacketHolder::Init: error");
    return NS_ERROR_DOM_MEDIA_DEMUXER_ERR;
  }

  aPacket = holder;
  return NS_OK;
}

void WebMDemuxer::PushAudioPacket(NesteggPacketHolder* aItem) {
  mAudioPackets.PushFront(aItem);
}

void WebMDemuxer::PushVideoPacket(NesteggPacketHolder* aItem) {
  mVideoPackets.PushFront(aItem);
}

nsresult WebMDemuxer::SeekInternal(TrackInfo::TrackType aType,
                                   const TimeUnit& aTarget) {
  EnsureUpToDateIndex();
  uint32_t trackToSeek = mHasVideo ? mVideoTrack : mAudioTrack;
  MOZ_ASSERT(aTarget.ToNanoseconds() >= 0, "Seek time can't be negative");
  uint64_t target = static_cast<uint64_t>(aTarget.ToNanoseconds());
  WEBM_DEBUG("Seeking to %lf", aTarget.ToSeconds());

  Reset(aType);

  if (mSeekPreroll) {
    uint64_t startTime = 0;
    if (!mBufferedState->GetStartTime(&startTime)) {
      startTime = 0;
    }
    WEBM_DEBUG("Seek Target: %f",
               TimeUnit::FromNanoseconds(target).ToSeconds());
    if (target < mSeekPreroll || target - mSeekPreroll < startTime) {
      target = startTime;
    } else {
      target -= mSeekPreroll;
    }
    WEBM_DEBUG("SeekPreroll: %f StartTime: %f Adjusted Target: %f",
               TimeUnit::FromNanoseconds(mSeekPreroll).ToSeconds(),
               TimeUnit::FromNanoseconds(startTime).ToSeconds(),
               TimeUnit::FromNanoseconds(target).ToSeconds());
  }
  int r = nestegg_track_seek(Context(aType), trackToSeek, target);
  if (r == -1) {
    WEBM_DEBUG("track_seek for track %u to %f failed, r=%d", trackToSeek,
               TimeUnit::FromNanoseconds(target).ToSeconds(), r);
    // Try seeking directly based on cluster information in memory.
    int64_t offset = 0;
    bool rv = mBufferedState->GetOffsetForTime(target, &offset);
    if (!rv) {
      WEBM_DEBUG("mBufferedState->GetOffsetForTime failed too");
      return NS_ERROR_FAILURE;
    }

    if (offset < 0) {
      WEBM_DEBUG("Unknow byte offset time for seek target %" PRIu64 "ns",
                 target);
      return NS_ERROR_FAILURE;
    }

    r = nestegg_offset_seek(Context(aType), static_cast<uint64_t>(offset));
    if (r == -1) {
      WEBM_DEBUG("and nestegg_offset_seek to %" PRIu64 " failed", offset);
      return NS_ERROR_FAILURE;
    }
    WEBM_DEBUG("got offset from buffered state: %" PRIu64 "", offset);
  }

  if (aType == TrackInfo::kAudioTrack) {
    mLastAudioFrameTime.reset();
  } else {
    mLastVideoFrameTime.reset();
  }

  return NS_OK;
}

bool WebMDemuxer::IsBufferedIntervalValid(uint64_t start, uint64_t end) {
  if (start > end) {
    // Buffered ranges are clamped to the media's start time and duration. Any
    // frames with timestamps outside that range are ignored, see bug 1697641
    // for more info.
    WEBM_DEBUG("Ignoring range %" PRIu64 "-%" PRIu64
               ", due to invalid interval (start > end).",
               start, end);
    return false;
  }

  auto startTime = TimeUnit::FromNanoseconds(start);
  auto endTime = TimeUnit::FromNanoseconds(end);

  if (startTime.IsNegative() || endTime.IsNegative()) {
    // We can get timestamps that are conceptually valid, but become
    // negative due to uint64 -> int64 conversion from TimeUnit. We should
    // not get negative timestamps, so guard against them.
    WEBM_DEBUG(
        "Invalid range %f-%f, likely result of uint64 -> int64 conversion.",
        startTime.ToSeconds(), endTime.ToSeconds());
    return false;
  }

  return true;
}

media::TimeIntervals WebMDemuxer::GetBuffered() {
  EnsureUpToDateIndex();
  AutoPinned<MediaResource> resource(
      Resource(TrackInfo::kVideoTrack).GetResource());

  media::TimeIntervals buffered;

  MediaByteRangeSet ranges;
  nsresult rv = resource->GetCachedRanges(ranges);
  if (NS_FAILED(rv)) {
    return media::TimeIntervals();
  }
  uint64_t duration = 0;
  uint64_t startOffset = 0;
  if (!nestegg_duration(Context(TrackInfo::kVideoTrack), &duration)) {
    if (mBufferedState->GetStartTime(&startOffset)) {
      duration += startOffset;
    }
    WEBM_DEBUG("Duration: %f StartTime: %f",
               TimeUnit::FromNanoseconds(duration).ToSeconds(),
               TimeUnit::FromNanoseconds(startOffset).ToSeconds());
  }
  for (uint32_t index = 0; index < ranges.Length(); index++) {
    uint64_t start, end;
    bool rv = mBufferedState->CalculateBufferedForRange(
        ranges[index].mStart, ranges[index].mEnd, &start, &end);
    if (rv) {
      NS_ASSERTION(startOffset <= start,
                   "startOffset negative or larger than start time");

      if (duration && end > duration) {
        WEBM_DEBUG("limit range to duration, end: %f duration: %f",
                   TimeUnit::FromNanoseconds(end).ToSeconds(),
                   TimeUnit::FromNanoseconds(duration).ToSeconds());
        end = duration;
      }

      if (!IsBufferedIntervalValid(start, end)) {
        WEBM_DEBUG("Invalid interval, bailing");
        break;
      }

      auto startTime = TimeUnit::FromNanoseconds(start);
      auto endTime = TimeUnit::FromNanoseconds(end);

      WEBM_DEBUG("add range %f-%f", startTime.ToSeconds(), endTime.ToSeconds());
      buffered += media::TimeInterval(startTime, endTime);
    }
  }
  return buffered;
}

bool WebMDemuxer::GetOffsetForTime(uint64_t aTime, int64_t* aOffset) {
  EnsureUpToDateIndex();
  return mBufferedState && mBufferedState->GetOffsetForTime(aTime, aOffset);
}

// WebMTrackDemuxer
WebMTrackDemuxer::WebMTrackDemuxer(WebMDemuxer* aParent,
                                   TrackInfo::TrackType aType,
                                   uint32_t aTrackNumber)
    : mParent(aParent), mType(aType), mNeedKeyframe(true) {
  mInfo = mParent->GetTrackInfo(aType, aTrackNumber);
  MOZ_ASSERT(mInfo);
}

WebMTrackDemuxer::~WebMTrackDemuxer() { mSamples.Reset(); }

UniquePtr<TrackInfo> WebMTrackDemuxer::GetInfo() const {
  return mInfo->Clone();
}

RefPtr<WebMTrackDemuxer::SeekPromise> WebMTrackDemuxer::Seek(
    const TimeUnit& aTime) {
  // Seeks to aTime. Upon success, SeekPromise will be resolved with the
  // actual time seeked to. Typically the random access point time

  auto seekTime = aTime;
  bool keyframe = false;

  mNeedKeyframe = true;

  do {
    mSamples.Reset();
    mParent->SeekInternal(mType, seekTime);
    nsresult rv = mParent->GetNextPacket(mType, &mSamples);
    if (NS_FAILED(rv)) {
      if (rv == NS_ERROR_DOM_MEDIA_END_OF_STREAM) {
        // Ignore the error for now, the next GetSample will be rejected with
        // EOS.
        return SeekPromise::CreateAndResolve(TimeUnit::Zero(), __func__);
      }
      return SeekPromise::CreateAndReject(rv, __func__);
    }

    // Check what time we actually seeked to.
    if (mSamples.GetSize() == 0) {
      // We can't determine if the seek succeeded at this stage, so break the
      // loop.
      break;
    }

    for (const auto& sample : mSamples) {
      seekTime = sample->mTime;
      keyframe = sample->mKeyframe;
      if (keyframe) {
        break;
      }
    }
    if (mType == TrackInfo::kVideoTrack &&
        !mInfo->GetAsVideoInfo()->HasAlpha()) {
      // We only perform a search for a keyframe on videos with alpha layer to
      // prevent potential regression for normal video (even though invalid)
      break;
    }
    if (!keyframe) {
      // We didn't find any keyframe, attempt to seek to the previous cluster.
      seekTime = mSamples.First()->mTime - TimeUnit::FromMicroseconds(1);
    }
  } while (!keyframe && seekTime >= TimeUnit::Zero());

  SetNextKeyFrameTime();

  return SeekPromise::CreateAndResolve(seekTime, __func__);
}

nsresult WebMTrackDemuxer::NextSample(RefPtr<MediaRawData>& aData) {
  nsresult rv = NS_ERROR_DOM_MEDIA_END_OF_STREAM;
  while (mSamples.GetSize() < 1 &&
         NS_SUCCEEDED((rv = mParent->GetNextPacket(mType, &mSamples)))) {
  }
  if (mSamples.GetSize()) {
    aData = mSamples.PopFront();
    return NS_OK;
  }
  WEBM_DEBUG("WebMTrackDemuxer::NextSample: error");
  return rv;
}

RefPtr<WebMTrackDemuxer::SamplesPromise> WebMTrackDemuxer::GetSamples(
    int32_t aNumSamples) {
  RefPtr<SamplesHolder> samples = new SamplesHolder;
  MOZ_ASSERT(aNumSamples);

  nsresult rv = NS_ERROR_DOM_MEDIA_END_OF_STREAM;

  while (aNumSamples) {
    RefPtr<MediaRawData> sample;
    rv = NextSample(sample);
    if (NS_FAILED(rv)) {
      break;
    }
    // Ignore empty samples.
    if (sample->Size() == 0) {
      WEBM_DEBUG(
          "0 sized sample encountered while getting samples, skipping it");
      continue;
    }
    if (mNeedKeyframe && !sample->mKeyframe) {
      continue;
    }
    if (!sample->HasValidTime()) {
      return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
                                             __func__);
    }
    mNeedKeyframe = false;
    samples->AppendSample(sample);
    aNumSamples--;
  }

  if (samples->GetSamples().IsEmpty()) {
    return SamplesPromise::CreateAndReject(rv, __func__);
  } else {
    UpdateSamples(samples->GetSamples());
    return SamplesPromise::CreateAndResolve(samples, __func__);
  }
}

void WebMTrackDemuxer::SetNextKeyFrameTime() {
  if (mType != TrackInfo::kVideoTrack || mParent->IsMediaSource()) {
    return;
  }

  auto frameTime = TimeUnit::Invalid();

  mNextKeyframeTime.reset();

  MediaRawDataQueue skipSamplesQueue;
  bool foundKeyframe = false;
  while (!foundKeyframe && mSamples.GetSize()) {
    RefPtr<MediaRawData> sample = mSamples.PopFront();
    if (sample->mKeyframe) {
      frameTime = sample->mTime;
      foundKeyframe = true;
    }
    skipSamplesQueue.Push(sample.forget());
  }
  Maybe<int64_t> startTime;
  if (skipSamplesQueue.GetSize()) {
    const RefPtr<MediaRawData>& sample = skipSamplesQueue.First();
    startTime.emplace(sample->mTimecode.ToMicroseconds());
  }
  // Demux and buffer frames until we find a keyframe.
  RefPtr<MediaRawData> sample;
  nsresult rv = NS_OK;
  while (!foundKeyframe && NS_SUCCEEDED((rv = NextSample(sample)))) {
    if (sample->mKeyframe) {
      frameTime = sample->mTime;
      foundKeyframe = true;
    }
    int64_t sampleTimecode = sample->mTimecode.ToMicroseconds();
    skipSamplesQueue.Push(sample.forget());
    if (!startTime) {
      startTime.emplace(sampleTimecode);
    } else if (!foundKeyframe &&
               sampleTimecode > startTime.ref() + MAX_LOOK_AHEAD) {
      WEBM_DEBUG("Couldn't find keyframe in a reasonable time, aborting");
      break;
    }
  }
  // We may have demuxed more than intended, so ensure that all frames are kept
  // in the right order.
  mSamples.PushFront(std::move(skipSamplesQueue));

  if (frameTime.IsValid()) {
    mNextKeyframeTime.emplace(frameTime);
    WEBM_DEBUG(
        "Next Keyframe %f (%u queued %.02fs)",
        mNextKeyframeTime.value().ToSeconds(), uint32_t(mSamples.GetSize()),
        (mSamples.Last()->mTimecode - mSamples.First()->mTimecode).ToSeconds());
  } else {
    WEBM_DEBUG("Couldn't determine next keyframe time  (%u queued)",
               uint32_t(mSamples.GetSize()));
  }
}

void WebMTrackDemuxer::Reset() {
  mSamples.Reset();
  media::TimeIntervals buffered = GetBuffered();
  mNeedKeyframe = true;
  if (!buffered.IsEmpty()) {
    WEBM_DEBUG("Seek to start point: %f", buffered.Start(0).ToSeconds());
    mParent->SeekInternal(mType, buffered.Start(0));
    SetNextKeyFrameTime();
  } else {
    mNextKeyframeTime.reset();
  }
}

void WebMTrackDemuxer::UpdateSamples(
    const nsTArray<RefPtr<MediaRawData>>& aSamples) {
  for (const auto& sample : aSamples) {
    if (sample->mCrypto.IsEncrypted()) {
      UniquePtr<MediaRawDataWriter> writer(sample->CreateWriter());
      writer->mCrypto.mIVSize = mInfo->mCrypto.mIVSize;
      writer->mCrypto.mKeyId.AppendElements(mInfo->mCrypto.mKeyId);
    }
  }
  if (mNextKeyframeTime.isNothing() ||
      aSamples.LastElement()->mTime >= mNextKeyframeTime.value()) {
    SetNextKeyFrameTime();
  }
}

nsresult WebMTrackDemuxer::GetNextRandomAccessPoint(TimeUnit* aTime) {
  if (mNextKeyframeTime.isNothing()) {
    // There's no next key frame.
    *aTime = TimeUnit::FromInfinity();
  } else {
    *aTime = mNextKeyframeTime.ref();
  }
  return NS_OK;
}

RefPtr<WebMTrackDemuxer::SkipAccessPointPromise>
WebMTrackDemuxer::SkipToNextRandomAccessPoint(const TimeUnit& aTimeThreshold) {
  uint32_t parsed = 0;
  bool found = false;
  RefPtr<MediaRawData> sample;
  nsresult rv = NS_OK;

  WEBM_DEBUG("TimeThreshold: %f", aTimeThreshold.ToSeconds());
  while (!found && NS_SUCCEEDED((rv = NextSample(sample)))) {
    parsed++;
    if (sample->mKeyframe && sample->mTime >= aTimeThreshold) {
      WEBM_DEBUG("next sample: %f (parsed: %d)", sample->mTime.ToSeconds(),
                 parsed);
      found = true;
      mSamples.Reset();
      mSamples.PushFront(sample.forget());
    }
  }
  if (NS_SUCCEEDED(rv)) {
    SetNextKeyFrameTime();
  }
  if (found) {
    return SkipAccessPointPromise::CreateAndResolve(parsed, __func__);
  } else {
    SkipFailureHolder failure(NS_ERROR_DOM_MEDIA_END_OF_STREAM, parsed);
    return SkipAccessPointPromise::CreateAndReject(std::move(failure),
                                                   __func__);
  }
}

media::TimeIntervals WebMTrackDemuxer::GetBuffered() {
  return mParent->GetBuffered();
}

void WebMTrackDemuxer::BreakCycles() { mParent = nullptr; }

int64_t WebMTrackDemuxer::GetEvictionOffset(const TimeUnit& aTime) {
  int64_t offset;
  int64_t nanos = aTime.ToNanoseconds();
  if (nanos < 0 ||
      !mParent->GetOffsetForTime(static_cast<uint64_t>(nanos), &offset)) {
    return 0;
  }

  return offset;
}
}  // namespace mozilla

#undef WEBM_DEBUG