Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

7 files changed, 2364 insertions, 0 deletions

diff --git a/dom/media/mp3/MP3Decoder.cpp b/dom/media/mp3/MP3Decoder.cpp
new file mode 100644
index 0000000000..efbe96cf4b
--- /dev/null
+++ b/dom/media/mp3/MP3Decoder.cpp
@@ -0,0 +1,45 @@
+/* -*- 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 "MP3Decoder.h"
+#include "MediaContainerType.h"
+#include "PDMFactory.h"
+
+namespace mozilla {
+
+/* static */
+bool MP3Decoder::IsEnabled() {
+  RefPtr<PDMFactory> platform = new PDMFactory();
+  return platform->SupportsMimeType("audio/mpeg"_ns) !=
+         media::DecodeSupport::Unsupported;
+}
+
+/* static */
+bool MP3Decoder::IsSupportedType(const MediaContainerType& aContainerType) {
+  if (aContainerType.Type() == MEDIAMIMETYPE("audio/mp3") ||
+      aContainerType.Type() == MEDIAMIMETYPE("audio/mpeg")) {
+    return IsEnabled() && (aContainerType.ExtendedType().Codecs().IsEmpty() ||
+                           aContainerType.ExtendedType().Codecs() == "mp3");
+  }
+  return false;
+}
+
+/* static */
+nsTArray<UniquePtr<TrackInfo>> MP3Decoder::GetTracksInfo(
+    const MediaContainerType& aType) {
+  nsTArray<UniquePtr<TrackInfo>> tracks;
+  if (!IsSupportedType(aType)) {
+    return tracks;
+  }
+
+  tracks.AppendElement(
+      CreateTrackInfoWithMIMETypeAndContainerTypeExtraParameters(
+          "audio/mpeg"_ns, aType));
+
+  return tracks;
+}
+
+}  // namespace mozilla
diff --git a/dom/media/mp3/MP3Decoder.h b/dom/media/mp3/MP3Decoder.h
new file mode 100644
index 0000000000..eab5387b51
--- /dev/null
+++ b/dom/media/mp3/MP3Decoder.h
@@ -0,0 +1,29 @@
+/* -*- 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/. */
+#ifndef MP3Decoder_h_
+#define MP3Decoder_h_
+
+#include "mozilla/UniquePtr.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+class MediaContainerType;
+class TrackInfo;
+
+class MP3Decoder {
+ public:
+  // Returns true if the MP3 backend is preffed on, and we're running on a
+  // platform that is likely to have decoders for the format.
+  static bool IsEnabled();
+  static bool IsSupportedType(const MediaContainerType& aContainerType);
+  static nsTArray<UniquePtr<TrackInfo>> GetTracksInfo(
+      const MediaContainerType& aType);
+};
+
+}  // namespace mozilla
+
+#endif
diff --git a/dom/media/mp3/MP3Demuxer.cpp b/dom/media/mp3/MP3Demuxer.cpp
new file mode 100644
index 0000000000..25d878b3be
--- /dev/null
+++ b/dom/media/mp3/MP3Demuxer.cpp
@@ -0,0 +1,890 @@
+/* -*- 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 "MP3Demuxer.h"
+
+#include <algorithm>
+#include <inttypes.h>
+#include <limits>
+
+#include "ByteWriter.h"
+#include "TimeUnits.h"
+#include "VideoUtils.h"
+#include "mozilla/Assertions.h"
+
+extern mozilla::LazyLogModule gMediaDemuxerLog;
+#define MP3LOG(msg, ...) \
+  DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Debug, msg, ##__VA_ARGS__)
+#define MP3LOGV(msg, ...) \
+  DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Verbose, msg, ##__VA_ARGS__)
+
+using mozilla::media::TimeInterval;
+using mozilla::media::TimeIntervals;
+using mozilla::media::TimeUnit;
+
+namespace mozilla {
+
+// MP3Demuxer
+
+MP3Demuxer::MP3Demuxer(MediaResource* aSource) : mSource(aSource) {
+  DDLINKCHILD("source", aSource);
+}
+
+bool MP3Demuxer::InitInternal() {
+  if (!mTrackDemuxer) {
+    mTrackDemuxer = new MP3TrackDemuxer(mSource);
+    DDLINKCHILD("track demuxer", mTrackDemuxer.get());
+  }
+  return mTrackDemuxer->Init();
+}
+
+RefPtr<MP3Demuxer::InitPromise> MP3Demuxer::Init() {
+  if (!InitInternal()) {
+    MP3LOG("MP3Demuxer::Init() failure: waiting for data");
+
+    return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_METADATA_ERR,
+                                        __func__);
+  }
+
+  MP3LOG("MP3Demuxer::Init() successful");
+  return InitPromise::CreateAndResolve(NS_OK, __func__);
+}
+
+uint32_t MP3Demuxer::GetNumberTracks(TrackInfo::TrackType aType) const {
+  return aType == TrackInfo::kAudioTrack ? 1u : 0u;
+}
+
+already_AddRefed<MediaTrackDemuxer> MP3Demuxer::GetTrackDemuxer(
+    TrackInfo::TrackType aType, uint32_t aTrackNumber) {
+  if (!mTrackDemuxer) {
+    return nullptr;
+  }
+  return RefPtr<MP3TrackDemuxer>(mTrackDemuxer).forget();
+}
+
+bool MP3Demuxer::IsSeekable() const { return true; }
+
+void MP3Demuxer::NotifyDataArrived() {
+  // TODO: bug 1169485.
+  NS_WARNING("Unimplemented function NotifyDataArrived");
+  MP3LOGV("NotifyDataArrived()");
+}
+
+void MP3Demuxer::NotifyDataRemoved() {
+  // TODO: bug 1169485.
+  NS_WARNING("Unimplemented function NotifyDataRemoved");
+  MP3LOGV("NotifyDataRemoved()");
+}
+
+// MP3TrackDemuxer
+
+MP3TrackDemuxer::MP3TrackDemuxer(MediaResource* aSource)
+    : mSource(aSource),
+      mFrameLock(false),
+      mOffset(0),
+      mFirstFrameOffset(0),
+      mNumParsedFrames(0),
+      mFrameIndex(0),
+      mTotalFrameLen(0),
+      mSamplesPerFrame(0),
+      mSamplesPerSecond(0),
+      mChannels(0) {
+  DDLINKCHILD("source", aSource);
+  Reset();
+}
+
+bool MP3TrackDemuxer::Init() {
+  Reset();
+  FastSeek(TimeUnit());
+  // Read the first frame to fetch sample rate and other meta data.
+  RefPtr<MediaRawData> frame(GetNextFrame(FindFirstFrame()));
+
+  MP3LOG("Init StreamLength()=%" PRId64 " first-frame-found=%d", StreamLength(),
+         !!frame);
+
+  if (!frame) {
+    return false;
+  }
+
+  // Rewind back to the stream begin to avoid dropping the first frame.
+  FastSeek(TimeUnit());
+
+  if (!mInfo) {
+    mInfo = MakeUnique<AudioInfo>();
+  }
+
+  mInfo->mRate = mSamplesPerSecond;
+  mInfo->mChannels = mChannels;
+  mInfo->mBitDepth = 16;
+  mInfo->mMimeType = "audio/mpeg";
+  mInfo->mDuration = Duration().valueOr(TimeUnit::FromInfinity());
+  Mp3CodecSpecificData mp3CodecData{};
+  if (mEncoderDelay) {
+    mp3CodecData.mEncoderDelayFrames = mEncoderDelay;
+    mp3CodecData.mEncoderPaddingFrames = mEncoderPadding;
+  }
+  mInfo->mCodecSpecificConfig =
+      AudioCodecSpecificVariant{std::move(mp3CodecData)};
+
+  MP3LOG("Init mInfo={mRate=%d mChannels=%d mBitDepth=%d mDuration=%s (%lfs)}",
+         mInfo->mRate, mInfo->mChannels, mInfo->mBitDepth,
+         mInfo->mDuration.ToString().get(), mInfo->mDuration.ToSeconds());
+
+  return mSamplesPerSecond && mChannels;
+}
+
+media::TimeUnit MP3TrackDemuxer::SeekPosition() const {
+  TimeUnit pos = Duration(mFrameIndex);
+  auto duration = Duration();
+  if (duration) {
+    pos = std::min(*duration, pos);
+  }
+  return pos;
+}
+
+const FrameParser::Frame& MP3TrackDemuxer::LastFrame() const {
+  return mParser.PrevFrame();
+}
+
+RefPtr<MediaRawData> MP3TrackDemuxer::DemuxSample() {
+  return GetNextFrame(FindNextFrame());
+}
+
+const ID3Parser::ID3Header& MP3TrackDemuxer::ID3Header() const {
+  return mParser.ID3Header();
+}
+
+const FrameParser::VBRHeader& MP3TrackDemuxer::VBRInfo() const {
+  return mParser.VBRInfo();
+}
+
+UniquePtr<TrackInfo> MP3TrackDemuxer::GetInfo() const { return mInfo->Clone(); }
+
+RefPtr<MP3TrackDemuxer::SeekPromise> MP3TrackDemuxer::Seek(
+    const TimeUnit& aTime) {
+  mRemainingEncoderPadding = AssertedCast<int32_t>(mEncoderPadding);
+  // Efficiently seek to the position.
+  FastSeek(aTime);
+  // Correct seek position by scanning the next frames.
+  const TimeUnit seekTime = ScanUntil(aTime);
+
+  return SeekPromise::CreateAndResolve(seekTime, __func__);
+}
+
+TimeUnit MP3TrackDemuxer::FastSeek(const TimeUnit& aTime) {
+  MP3LOG("FastSeek(%" PRId64 ") avgFrameLen=%f mNumParsedFrames=%" PRIu64
+         " mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
+         aTime.ToMicroseconds(), AverageFrameLength(), mNumParsedFrames,
+         mFrameIndex, mOffset);
+
+  const auto& vbr = mParser.VBRInfo();
+  if (aTime.IsZero()) {
+    // Quick seek to the beginning of the stream.
+    mFrameIndex = 0;
+  } else if (vbr.IsTOCPresent() && Duration() &&
+             *Duration() != TimeUnit::Zero()) {
+    // Use TOC for more precise seeking.
+    mFrameIndex = FrameIndexFromOffset(vbr.Offset(aTime, Duration().value()));
+  } else if (AverageFrameLength() > 0) {
+    mFrameIndex = FrameIndexFromTime(aTime);
+  }
+
+  mOffset = OffsetFromFrameIndex(mFrameIndex);
+
+  if (mOffset > mFirstFrameOffset && StreamLength() > 0) {
+    mOffset = std::min(StreamLength() - 1, mOffset);
+  }
+
+  mParser.EndFrameSession();
+
+  MP3LOG("FastSeek End TOC=%d avgFrameLen=%f mNumParsedFrames=%" PRIu64
+         " mFrameIndex=%" PRId64 " mFirstFrameOffset=%" PRId64
+         " mOffset=%" PRIu64 " SL=%" PRId64 " NumBytes=%u",
+         vbr.IsTOCPresent(), AverageFrameLength(), mNumParsedFrames,
+         mFrameIndex, mFirstFrameOffset, mOffset, StreamLength(),
+         vbr.NumBytes().valueOr(0));
+
+  return Duration(mFrameIndex);
+}
+
+TimeUnit MP3TrackDemuxer::ScanUntil(const TimeUnit& aTime) {
+  MP3LOG("ScanUntil(%" PRId64 ") avgFrameLen=%f mNumParsedFrames=%" PRIu64
+         " mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
+         aTime.ToMicroseconds(), AverageFrameLength(), mNumParsedFrames,
+         mFrameIndex, mOffset);
+
+  if (aTime.IsZero()) {
+    return FastSeek(aTime);
+  }
+
+  if (Duration(mFrameIndex) > aTime) {
+    // We've seeked past the target time, rewind back a little to correct it.
+    const int64_t rewind = aTime.ToMicroseconds() / 100;
+    FastSeek(aTime - TimeUnit::FromMicroseconds(rewind));
+  }
+
+  if (Duration(mFrameIndex + 1) > aTime) {
+    return SeekPosition();
+  }
+
+  MediaByteRange nextRange = FindNextFrame();
+  while (SkipNextFrame(nextRange) && Duration(mFrameIndex + 1) < aTime) {
+    nextRange = FindNextFrame();
+    MP3LOGV("ScanUntil* avgFrameLen=%f mNumParsedFrames=%" PRIu64
+            " mFrameIndex=%" PRId64 " mOffset=%" PRIu64 " Duration=%" PRId64,
+            AverageFrameLength(), mNumParsedFrames, mFrameIndex, mOffset,
+            Duration(mFrameIndex + 1).ToMicroseconds());
+  }
+
+  MP3LOG("ScanUntil End avgFrameLen=%f mNumParsedFrames=%" PRIu64
+         " mFrameIndex=%" PRId64 " mOffset=%" PRIu64,
+         AverageFrameLength(), mNumParsedFrames, mFrameIndex, mOffset);
+
+  return SeekPosition();
+}
+
+RefPtr<MP3TrackDemuxer::SamplesPromise> MP3TrackDemuxer::GetSamples(
+    int32_t aNumSamples) {
+  MP3LOGV("GetSamples(%d) Begin mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
+          " mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
+          " mSamplesPerFrame=%d mSamplesPerSecond=%d mChannels=%d",
+          aNumSamples, mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
+          mSamplesPerFrame, mSamplesPerSecond, mChannels);
+
+  if (!aNumSamples) {
+    return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
+                                           __func__);
+  }
+
+  RefPtr<SamplesHolder> frames = new SamplesHolder();
+
+  while (aNumSamples--) {
+    RefPtr<MediaRawData> frame(GetNextFrame(FindNextFrame()));
+    if (!frame) {
+      break;
+    }
+    if (!frame->HasValidTime()) {
+      return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
+                                             __func__);
+    }
+    frames->AppendSample(frame);
+  }
+
+  MP3LOGV("GetSamples() End mSamples.Size()=%zu aNumSamples=%d mOffset=%" PRIu64
+          " mNumParsedFrames=%" PRIu64 " mFrameIndex=%" PRId64
+          " mTotalFrameLen=%" PRIu64
+          " mSamplesPerFrame=%d mSamplesPerSecond=%d "
+          "mChannels=%d",
+          frames->GetSamples().Length(), aNumSamples, mOffset, mNumParsedFrames,
+          mFrameIndex, mTotalFrameLen, mSamplesPerFrame, mSamplesPerSecond,
+          mChannels);
+
+  if (frames->GetSamples().IsEmpty()) {
+    return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_END_OF_STREAM,
+                                           __func__);
+  }
+  return SamplesPromise::CreateAndResolve(frames, __func__);
+}
+
+void MP3TrackDemuxer::Reset() {
+  MP3LOG("Reset()");
+
+  FastSeek(TimeUnit());
+  mParser.Reset();
+}
+
+RefPtr<MP3TrackDemuxer::SkipAccessPointPromise>
+MP3TrackDemuxer::SkipToNextRandomAccessPoint(const TimeUnit& aTimeThreshold) {
+  // Will not be called for audio-only resources.
+  return SkipAccessPointPromise::CreateAndReject(
+      SkipFailureHolder(NS_ERROR_DOM_MEDIA_DEMUXER_ERR, 0), __func__);
+}
+
+int64_t MP3TrackDemuxer::GetResourceOffset() const { return mOffset; }
+
+TimeIntervals MP3TrackDemuxer::GetBuffered() {
+  AutoPinned<MediaResource> stream(mSource.GetResource());
+  TimeIntervals buffered;
+
+  if (Duration() && stream->IsDataCachedToEndOfResource(0)) {
+    // Special case completely cached files. This also handles local files.
+    buffered += TimeInterval(TimeUnit(), *Duration());
+    MP3LOGV("buffered = [[%" PRId64 ", %" PRId64 "]]",
+            TimeUnit().ToMicroseconds(), Duration()->ToMicroseconds());
+    return buffered;
+  }
+
+  MediaByteRangeSet ranges;
+  nsresult rv = stream->GetCachedRanges(ranges);
+  NS_ENSURE_SUCCESS(rv, buffered);
+
+  for (const auto& range : ranges) {
+    if (range.IsEmpty()) {
+      continue;
+    }
+    TimeUnit start = Duration(FrameIndexFromOffset(range.mStart));
+    TimeUnit end = Duration(FrameIndexFromOffset(range.mEnd));
+    MP3LOGV("buffered += [%" PRId64 ", %" PRId64 "]", start.ToMicroseconds(),
+            end.ToMicroseconds());
+    buffered += TimeInterval(start, end);
+  }
+
+  // If the number of frames reported by the header is valid,
+  // the duration calculated from it is the maximal duration.
+  if (ValidNumAudioFrames() && Duration()) {
+    TimeInterval duration = TimeInterval(TimeUnit(), *Duration());
+    return buffered.Intersection(duration);
+  }
+
+  return buffered;
+}
+
+int64_t MP3TrackDemuxer::StreamLength() const { return mSource.GetLength(); }
+
+media::NullableTimeUnit NothingIfNegative(TimeUnit aDuration) {
+  if (aDuration.IsNegative()) {
+    return Nothing();
+  }
+  return Some(aDuration);
+}
+
+media::NullableTimeUnit MP3TrackDemuxer::Duration() const {
+  if (!mNumParsedFrames) {
+    return Nothing();
+  }
+
+  int64_t numFrames = 0;
+  const auto numAudioFrames = ValidNumAudioFrames();
+  if (numAudioFrames) {
+    // VBR headers don't include the VBR header frame.
+    numFrames = numAudioFrames.value() + 1;
+    return NothingIfNegative(Duration(numFrames) -
+                             (EncoderDelay() + Padding()));
+  }
+
+  const int64_t streamLen = StreamLength();
+  if (streamLen < 0) {  // Live streams.
+    // Unknown length, we can't estimate duration.
+    return Nothing();
+  }
+  // We can't early return when streamLen < 0 before checking numAudioFrames
+  // since some live radio will give an opening remark before playing music
+  // and the duration of the opening talk can be calculated by numAudioFrames.
+
+  int64_t size = streamLen - mFirstFrameOffset;
+  MOZ_ASSERT(size);
+
+  if (mParser.ID3v1MetadataFound() && size > 128) {
+    size -= 128;
+  }
+
+  // If it's CBR, calculate the duration by bitrate.
+  if (!mParser.VBRInfo().IsValid()) {
+    const uint32_t bitrate = mParser.CurrentFrame().Header().Bitrate();
+    return NothingIfNegative(
+        media::TimeUnit::FromSeconds(static_cast<double>(size) * 8 / bitrate));
+  }
+
+  if (AverageFrameLength() > 0) {
+    numFrames = std::lround(AssertedCast<double>(size) / AverageFrameLength());
+  }
+
+  return NothingIfNegative(Duration(numFrames) - (EncoderDelay() + Padding()));
+}
+
+TimeUnit MP3TrackDemuxer::Duration(int64_t aNumFrames) const {
+  if (!mSamplesPerSecond) {
+    return TimeUnit::Invalid();
+  }
+
+  const int64_t frameCount = aNumFrames * mSamplesPerFrame;
+  return TimeUnit(frameCount, mSamplesPerSecond);
+}
+
+MediaByteRange MP3TrackDemuxer::FindFirstFrame() {
+  // We attempt to find multiple successive frames to avoid locking onto a false
+  // positive if we're fed a stream that has been cut mid-frame.
+  // For compatibility reasons we have to use the same frame count as Chrome,
+  // since some web sites actually use a file that short to test our playback
+  // capabilities.
+  static const int MIN_SUCCESSIVE_FRAMES = 3;
+  mFrameLock = false;
+
+  MediaByteRange candidateFrame = FindNextFrame();
+  int numSuccFrames = candidateFrame.Length() > 0;
+  MediaByteRange currentFrame = candidateFrame;
+  MP3LOGV("FindFirst() first candidate frame: mOffset=%" PRIu64
+          " Length()=%" PRIu64,
+          candidateFrame.mStart, candidateFrame.Length());
+
+  while (candidateFrame.Length()) {
+    mParser.EndFrameSession();
+    mOffset = currentFrame.mEnd;
+    const MediaByteRange prevFrame = currentFrame;
+
+    // FindNextFrame() here will only return frames consistent with our
+    // candidate frame.
+    currentFrame = FindNextFrame();
+    numSuccFrames += currentFrame.Length() > 0;
+    // Multiple successive false positives, which wouldn't be caught by the
+    // consistency checks alone, can be detected by wrong alignment (non-zero
+    // gap between frames).
+    const int64_t frameSeparation = currentFrame.mStart - prevFrame.mEnd;
+
+    if (!currentFrame.Length() || frameSeparation != 0) {
+      MP3LOGV(
+          "FindFirst() not enough successive frames detected, "
+          "rejecting candidate frame: successiveFrames=%d, last "
+          "Length()=%" PRIu64 ", last frameSeparation=%" PRId64,
+          numSuccFrames, currentFrame.Length(), frameSeparation);
+
+      mParser.ResetFrameData();
+      mOffset = candidateFrame.mStart + 1;
+      candidateFrame = FindNextFrame();
+      numSuccFrames = candidateFrame.Length() > 0;
+      currentFrame = candidateFrame;
+      MP3LOGV("FindFirst() new candidate frame: mOffset=%" PRIu64
+              " Length()=%" PRIu64,
+              candidateFrame.mStart, candidateFrame.Length());
+    } else if (numSuccFrames >= MIN_SUCCESSIVE_FRAMES) {
+      MP3LOG(
+          "FindFirst() accepting candidate frame: "
+          "successiveFrames=%d",
+          numSuccFrames);
+      mFrameLock = true;
+      return candidateFrame;
+    } else if (prevFrame.mStart == mParser.TotalID3HeaderSize() &&
+               currentFrame.mEnd == StreamLength()) {
+      // We accept streams with only two frames if both frames are valid. This
+      // is to handle very short files and provide parity with Chrome. See
+      // bug 1432195 for more information. This will not handle short files
+      // with a trailing tag, but as of writing we lack infrastructure to
+      // handle such tags.
+      MP3LOG(
+          "FindFirst() accepting candidate frame for short stream: "
+          "successiveFrames=%d",
+          numSuccFrames);
+      mFrameLock = true;
+      return candidateFrame;
+    }
+  }
+
+  MP3LOG("FindFirst() no suitable first frame found");
+  return candidateFrame;
+}
+
+static bool VerifyFrameConsistency(const FrameParser::Frame& aFrame1,
+                                   const FrameParser::Frame& aFrame2) {
+  const auto& h1 = aFrame1.Header();
+  const auto& h2 = aFrame2.Header();
+
+  return h1.IsValid() && h2.IsValid() && h1.Layer() == h2.Layer() &&
+         h1.SlotSize() == h2.SlotSize() &&
+         h1.SamplesPerFrame() == h2.SamplesPerFrame() &&
+         h1.Channels() == h2.Channels() && h1.SampleRate() == h2.SampleRate() &&
+         h1.RawVersion() == h2.RawVersion() &&
+         h1.RawProtection() == h2.RawProtection();
+}
+
+MediaByteRange MP3TrackDemuxer::FindNextFrame() {
+  static const int BUFFER_SIZE = 64;
+  static const uint32_t MAX_SKIPPABLE_BYTES = 1024 * BUFFER_SIZE;
+
+  MP3LOGV("FindNext() Begin mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
+          " mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
+          " mSamplesPerFrame=%d mSamplesPerSecond=%d mChannels=%d",
+          mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
+          mSamplesPerFrame, mSamplesPerSecond, mChannels);
+
+  uint8_t buffer[BUFFER_SIZE];
+  uint32_t read = 0;
+
+  bool foundFrame = false;
+  int64_t frameHeaderOffset = 0;
+  int64_t startOffset = mOffset;
+  const bool searchingForID3 = !mParser.ID3Header().HasSizeBeenSet();
+
+  // Check whether we've found a valid MPEG frame.
+  while (!foundFrame) {
+    // How many bytes we can go without finding a valid MPEG frame
+    // (effectively rounded up to the next full buffer size multiple, as we
+    // only check this before reading the next set of data into the buffer).
+
+    // This default value of 0 will be used during testing whether we're being
+    // fed a valid stream, which shouldn't have any gaps between frames.
+    uint32_t maxSkippableBytes = 0;
+
+    if (!mParser.FirstFrame().Length()) {
+      // We're looking for the first valid frame. A well-formed file should
+      // have its first frame header right at the start (skipping an ID3 tag
+      // if necessary), but in order to support files that might have been
+      // improperly cut, we search the first few kB for a frame header.
+      maxSkippableBytes = MAX_SKIPPABLE_BYTES;
+      // Since we're counting the skipped bytes from the offset we started
+      // this parsing session with, we need to discount the ID3 tag size only
+      // if we were looking for one during the current frame parsing session.
+      if (searchingForID3) {
+        maxSkippableBytes += mParser.TotalID3HeaderSize();
+      }
+    } else if (mFrameLock) {
+      // We've found a valid MPEG stream, so don't impose any limits
+      // to allow skipping corrupted data until we hit EOS.
+      maxSkippableBytes = std::numeric_limits<uint32_t>::max();
+    }
+
+    if ((mOffset - startOffset > maxSkippableBytes) ||
+        (read = Read(buffer, mOffset, BUFFER_SIZE)) == 0) {
+      MP3LOG(
+          "FindNext() EOS or exceeded maxSkippeableBytes without a frame "
+          "(read: %d)",
+          read);
+      // This is not a valid MPEG audio stream or we've reached EOS, give up.
+      break;
+    }
+
+    BufferReader reader(buffer, read);
+    uint32_t bytesToSkip = 0;
+    auto res = mParser.Parse(&reader, &bytesToSkip);
+    foundFrame = res.unwrapOr(false);
+    int64_t readerOffset = static_cast<int64_t>(reader.Offset());
+    frameHeaderOffset = mOffset + readerOffset - FrameParser::FrameHeader::SIZE;
+
+    // If we've found neither an MPEG frame header nor an ID3v2 tag,
+    // the reader shouldn't have any bytes remaining.
+    MOZ_ASSERT(foundFrame || bytesToSkip || !reader.Remaining());
+
+    if (foundFrame && mParser.FirstFrame().Length() &&
+        !VerifyFrameConsistency(mParser.FirstFrame(), mParser.CurrentFrame())) {
+      MP3LOG("Skipping frame");
+      // We've likely hit a false-positive, ignore it and proceed with the
+      // search for the next valid frame.
+      foundFrame = false;
+      mOffset = frameHeaderOffset + 1;
+      mParser.EndFrameSession();
+    } else {
+      // Advance mOffset by the amount of bytes read and if necessary,
+      // skip an ID3v2 tag which stretches beyond the current buffer.
+      NS_ENSURE_TRUE(mOffset + read + bytesToSkip > mOffset,
+                     MediaByteRange(0, 0));
+      mOffset += static_cast<int64_t>(read + bytesToSkip);
+    }
+  }
+
+  if (StreamLength() != -1) {
+    mEOS = frameHeaderOffset + mParser.CurrentFrame().Length() + BUFFER_SIZE >
+           StreamLength();
+  }
+
+  if (!foundFrame || !mParser.CurrentFrame().Length()) {
+    MP3LOG("FindNext() Exit foundFrame=%d mParser.CurrentFrame().Length()=%d ",
+           foundFrame, mParser.CurrentFrame().Length());
+    return {0, 0};
+  }
+
+  MP3LOGV("FindNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
+          " mFrameIndex=%" PRId64 " frameHeaderOffset=%" PRId64
+          " mTotalFrameLen=%" PRIu64
+          " mSamplesPerFrame=%d mSamplesPerSecond=%d"
+          " mChannels=%d, mEOS=%s",
+          mOffset, mNumParsedFrames, mFrameIndex, frameHeaderOffset,
+          mTotalFrameLen, mSamplesPerFrame, mSamplesPerSecond, mChannels,
+          mEOS ? "true" : "false");
+
+  return {frameHeaderOffset,
+          frameHeaderOffset + mParser.CurrentFrame().Length()};
+}
+
+bool MP3TrackDemuxer::SkipNextFrame(const MediaByteRange& aRange) {
+  if (!mNumParsedFrames || !aRange.Length()) {
+    // We can't skip the first frame, since it could contain VBR headers.
+    RefPtr<MediaRawData> frame(GetNextFrame(aRange));
+    return frame;
+  }
+
+  UpdateState(aRange);
+
+  MP3LOGV("SkipNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
+          " mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
+          " mSamplesPerFrame=%d mSamplesPerSecond=%d mChannels=%d",
+          mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
+          mSamplesPerFrame, mSamplesPerSecond, mChannels);
+
+  return true;
+}
+
+media::TimeUnit MP3TrackDemuxer::EncoderDelay() const {
+  return media::TimeUnit(mEncoderDelay, mSamplesPerSecond);
+}
+
+uint32_t MP3TrackDemuxer::EncoderDelayFrames() const { return mEncoderDelay; }
+
+media::TimeUnit MP3TrackDemuxer::Padding() const {
+  return media::TimeUnit(mEncoderPadding, mSamplesPerSecond);
+}
+
+uint32_t MP3TrackDemuxer::PaddingFrames() const { return mEncoderPadding; }
+
+already_AddRefed<MediaRawData> MP3TrackDemuxer::GetNextFrame(
+    const MediaByteRange& aRange) {
+  MP3LOG("GetNext() Begin({mStart=%" PRId64 " Length()=%" PRId64 "})",
+         aRange.mStart, aRange.Length());
+  if (!aRange.Length()) {
+    return nullptr;
+  }
+
+  RefPtr<MediaRawData> frame = new MediaRawData();
+  frame->mOffset = aRange.mStart;
+
+  UniquePtr<MediaRawDataWriter> frameWriter(frame->CreateWriter());
+  if (!frameWriter->SetSize(static_cast<size_t>(aRange.Length()))) {
+    MP3LOG("GetNext() Exit failed to allocated media buffer");
+    return nullptr;
+  }
+
+  const uint32_t read =
+      Read(frameWriter->Data(), frame->mOffset, frame->Size());
+
+  if (read != aRange.Length()) {
+    MP3LOG("GetNext() Exit read=%u frame->Size()=%zu", read, frame->Size());
+    return nullptr;
+  }
+
+  UpdateState(aRange);
+
+  if (mNumParsedFrames == 1) {
+    // First frame parsed, let's read VBR info if available.
+    BufferReader reader(frame->Data(), frame->Size());
+    mFirstFrameOffset = frame->mOffset;
+
+    if (mParser.ParseVBRHeader(&reader)) {
+      // Parsing was successful
+      if (mParser.VBRInfo().Type() == FrameParser::VBRHeader::XING) {
+        MP3LOG("XING header present, skipping encoder delay (%u frames)",
+               mParser.VBRInfo().EncoderDelay());
+        mEncoderDelay = mParser.VBRInfo().EncoderDelay();
+        mEncoderPadding = mParser.VBRInfo().EncoderPadding();
+        // Padding is encoded as a 12-bit unsigned number so this is fine.
+        mRemainingEncoderPadding = AssertedCast<int32_t>(mEncoderPadding);
+        if (mEncoderDelay == 0) {
+          // Skip the VBR frame + the decoder delay, that is always 529 frames
+          // in practice for the decoder we're using.
+          mEncoderDelay = mSamplesPerFrame + 529;
+          MP3LOG(
+              "No explicit delay present in vbr header, delay is assumed to be "
+              "%u frames\n",
+              mEncoderDelay);
+        }
+      } else if (mParser.VBRInfo().Type() == FrameParser::VBRHeader::VBRI) {
+        MP3LOG("VBRI header present, skipping encoder delay (%u frames)",
+               mParser.VBRInfo().EncoderDelay());
+        mEncoderDelay = mParser.VBRInfo().EncoderDelay();
+      }
+    }
+  }
+
+  TimeUnit rawPts = Duration(mFrameIndex - 1) - EncoderDelay();
+  TimeUnit rawDuration = Duration(1);
+  TimeUnit rawEnd = rawPts + rawDuration;
+
+  frame->mTime = std::max(TimeUnit::Zero(mSamplesPerSecond), rawPts);
+
+  frame->mDuration = Duration(1);
+  frame->mTimecode = frame->mTime;
+  frame->mKeyframe = true;
+  frame->mEOS = mEOS;
+
+  // Handle decoder delay. A packet must be trimmed if its pts, adjusted for
+  // decoder delay, is negative. A packet can be trimmed entirely.
+  if (rawPts.IsNegative()) {
+    frame->mDuration =
+        std::max(TimeUnit::Zero(mSamplesPerSecond), rawEnd - frame->mTime);
+  }
+
+  // It's possible to create an mp3 file that has a padding value that somehow
+  // spans multiple packets. In that case the duration is probably known,
+  // because it's probably a VBR file with a XING header (that has a duration
+  // field). Use the duration to be able to set the correct duration on
+  // packets that aren't the last one.
+  // For most files, the padding is less than a packet, it's simply substracted.
+  if (mParser.VBRInfo().Type() == FrameParser::VBRHeader::XING &&
+      mRemainingEncoderPadding > 0 &&
+      frame->GetEndTime() > Duration().valueOr(TimeUnit::FromInfinity())) {
+    TimeUnit duration = Duration().value();
+    TimeUnit inPaddingZone = frame->GetEndTime() - duration;
+    TimeUnit originalEnd = frame->GetEndTime();
+    TimeUnit originalPts = frame->mTime;
+    frame->mDuration -= inPaddingZone;
+    // Packet is entirely padding and will be completely discarded by the
+    // decoder.
+    if (frame->mDuration.IsNegative()) {
+      frame->mDuration = TimeUnit::Zero(mSamplesPerSecond);
+    }
+    int32_t paddingFrames =
+        AssertedCast<int32_t>(inPaddingZone.ToTicksAtRate(mSamplesPerSecond));
+    if (mRemainingEncoderPadding >= paddingFrames) {
+      mRemainingEncoderPadding -= paddingFrames;
+    } else {
+      mRemainingEncoderPadding = 0;
+    }
+    MP3LOG("Trimming [%s, %s] to [%s,%s] (padding) (stream duration: %s)",
+           originalPts.ToString().get(), originalEnd.ToString().get(),
+           frame->mTime.ToString().get(), frame->GetEndTime().ToString().get(),
+           duration.ToString().get());
+  } else if (frame->mEOS &&
+             mRemainingEncoderPadding <=
+                 frame->mDuration.ToTicksAtRate(mSamplesPerSecond)) {
+    frame->mDuration -= TimeUnit(mRemainingEncoderPadding, mSamplesPerSecond);
+    MOZ_ASSERT(frame->mDuration.IsPositiveOrZero());
+    MP3LOG("Trimming last packet %s to [%s,%s]", Padding().ToString().get(),
+           frame->mTime.ToString().get(), frame->GetEndTime().ToString().get());
+  }
+
+  MP3LOGV("GetNext() End mOffset=%" PRIu64 " mNumParsedFrames=%" PRIu64
+          " mFrameIndex=%" PRId64 " mTotalFrameLen=%" PRIu64
+          " mSamplesPerFrame=%d mSamplesPerSecond=%d mChannels=%d, mEOS=%s",
+          mOffset, mNumParsedFrames, mFrameIndex, mTotalFrameLen,
+          mSamplesPerFrame, mSamplesPerSecond, mChannels,
+          mEOS ? "true" : "false");
+
+  // It's possible for the duration of a frame to be zero if the frame is to be
+  // trimmed entirely because it's fully comprised of decoder delay samples.
+  // This is common at the beginning of an stream.
+  MOZ_ASSERT(frame->mDuration.IsPositiveOrZero());
+
+  MP3LOG("Packet demuxed: pts [%s, %s] (duration: %s)",
+         frame->mTime.ToString().get(), frame->GetEndTime().ToString().get(),
+         frame->mDuration.ToString().get());
+
+  // Indicate original packet information to trim after decoding.
+  if (frame->mDuration != rawDuration) {
+    frame->mOriginalPresentationWindow = Some(TimeInterval{rawPts, rawEnd});
+    MP3LOG("Total packet time excluding trimming: [%s, %s]",
+           rawPts.ToString().get(), rawEnd.ToString().get());
+  }
+
+  return frame.forget();
+}
+
+int64_t MP3TrackDemuxer::OffsetFromFrameIndex(int64_t aFrameIndex) const {
+  int64_t offset = 0;
+  const auto& vbr = mParser.VBRInfo();
+
+  if (vbr.IsComplete()) {
+    offset = mFirstFrameOffset + aFrameIndex * vbr.NumBytes().value() /
+                                     vbr.NumAudioFrames().value();
+  } else if (AverageFrameLength() > 0) {
+    offset = mFirstFrameOffset +
+             AssertedCast<int64_t>(static_cast<float>(aFrameIndex) *
+                                   AverageFrameLength());
+  }
+
+  MP3LOGV("OffsetFromFrameIndex(%" PRId64 ") -> %" PRId64, aFrameIndex, offset);
+  return std::max<int64_t>(mFirstFrameOffset, offset);
+}
+
+int64_t MP3TrackDemuxer::FrameIndexFromOffset(int64_t aOffset) const {
+  int64_t frameIndex = 0;
+  const auto& vbr = mParser.VBRInfo();
+
+  if (vbr.IsComplete()) {
+    frameIndex =
+        AssertedCast<int64_t>(static_cast<float>(aOffset - mFirstFrameOffset) /
+                              static_cast<float>(vbr.NumBytes().value()) *
+                              static_cast<float>(vbr.NumAudioFrames().value()));
+    frameIndex = std::min<int64_t>(vbr.NumAudioFrames().value(), frameIndex);
+  } else if (AverageFrameLength() > 0) {
+    frameIndex = AssertedCast<int64_t>(
+        static_cast<float>(aOffset - mFirstFrameOffset) / AverageFrameLength());
+  }
+
+  MP3LOGV("FrameIndexFromOffset(%" PRId64 ") -> %" PRId64, aOffset, frameIndex);
+  return std::max<int64_t>(0, frameIndex);
+}
+
+int64_t MP3TrackDemuxer::FrameIndexFromTime(
+    const media::TimeUnit& aTime) const {
+  int64_t frameIndex = 0;
+  if (mSamplesPerSecond > 0 && mSamplesPerFrame > 0) {
+    frameIndex = AssertedCast<int64_t>(
+        aTime.ToSeconds() * mSamplesPerSecond / mSamplesPerFrame - 1);
+  }
+
+  MP3LOGV("FrameIndexFromOffset(%fs) -> %" PRId64, aTime.ToSeconds(),
+          frameIndex);
+  return std::max<int64_t>(0, frameIndex);
+}
+
+void MP3TrackDemuxer::UpdateState(const MediaByteRange& aRange) {
+  // Prevent overflow.
+  if (mTotalFrameLen + aRange.Length() < mTotalFrameLen) {
+    // These variables have a linear dependency and are only used to derive the
+    // average frame length.
+    mTotalFrameLen /= 2;
+    mNumParsedFrames /= 2;
+  }
+
+  // Full frame parsed, move offset to its end.
+  mOffset = aRange.mEnd;
+
+  mTotalFrameLen += aRange.Length();
+
+  if (!mSamplesPerFrame) {
+    mSamplesPerFrame = mParser.CurrentFrame().Header().SamplesPerFrame();
+    mSamplesPerSecond = mParser.CurrentFrame().Header().SampleRate();
+    mChannels = mParser.CurrentFrame().Header().Channels();
+  }
+
+  ++mNumParsedFrames;
+  ++mFrameIndex;
+  MOZ_ASSERT(mFrameIndex > 0);
+
+  // Prepare the parser for the next frame parsing session.
+  mParser.EndFrameSession();
+}
+
+uint32_t MP3TrackDemuxer::Read(uint8_t* aBuffer, int64_t aOffset,
+                               uint32_t aSize) {
+  MP3LOGV("MP3TrackDemuxer::Read(%p %" PRId64 " %d)", aBuffer, aOffset, aSize);
+
+  const int64_t streamLen = StreamLength();
+  if (mInfo && streamLen > 0) {
+    // Prevent blocking reads after successful initialization.
+    int64_t max = streamLen > aOffset ? streamLen - aOffset : 0;
+    aSize = std::min<int64_t>(aSize, max);
+  }
+
+  uint32_t read = 0;
+  MP3LOGV("MP3TrackDemuxer::Read        -> ReadAt(%u)", aSize);
+  const nsresult rv = mSource.ReadAt(aOffset, reinterpret_cast<char*>(aBuffer),
+                                     static_cast<uint32_t>(aSize), &read);
+  NS_ENSURE_SUCCESS(rv, 0);
+  return read;
+}
+
+double MP3TrackDemuxer::AverageFrameLength() const {
+  if (mNumParsedFrames) {
+    return static_cast<double>(mTotalFrameLen) /
+           static_cast<double>(mNumParsedFrames);
+  }
+  const auto& vbr = mParser.VBRInfo();
+  if (vbr.IsComplete() && vbr.NumAudioFrames().value() + 1) {
+    return static_cast<double>(vbr.NumBytes().value()) /
+           (vbr.NumAudioFrames().value() + 1);
+  }
+  return 0.0;
+}
+
+Maybe<uint32_t> MP3TrackDemuxer::ValidNumAudioFrames() const {
+  return mParser.VBRInfo().IsValid() &&
+                 mParser.VBRInfo().NumAudioFrames().valueOr(0) + 1 > 1
+             ? mParser.VBRInfo().NumAudioFrames()
+             : Nothing();
+}
+
+}  // namespace mozilla
+
+#undef MP3LOG
+#undef MP3LOGV
diff --git a/dom/media/mp3/MP3Demuxer.h b/dom/media/mp3/MP3Demuxer.h
new file mode 100644
index 0000000000..5189e82acf
--- /dev/null
+++ b/dom/media/mp3/MP3Demuxer.h
@@ -0,0 +1,187 @@
+/* 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/. */
+
+#ifndef MP3_DEMUXER_H_
+#define MP3_DEMUXER_H_
+
+#include "MediaDataDemuxer.h"
+#include "MediaResource.h"
+#include "MP3FrameParser.h"
+
+namespace mozilla {
+
+class MP3TrackDemuxer;
+
+DDLoggedTypeDeclNameAndBase(MP3Demuxer, MediaDataDemuxer);
+DDLoggedTypeNameAndBase(MP3TrackDemuxer, MediaTrackDemuxer);
+
+class MP3Demuxer : public MediaDataDemuxer,
+                   public DecoderDoctorLifeLogger<MP3Demuxer> {
+ public:
+  // MediaDataDemuxer interface.
+  explicit MP3Demuxer(MediaResource* aSource);
+  RefPtr<InitPromise> Init() override;
+  uint32_t GetNumberTracks(TrackInfo::TrackType aType) const override;
+  already_AddRefed<MediaTrackDemuxer> GetTrackDemuxer(
+      TrackInfo::TrackType aType, uint32_t aTrackNumber) override;
+  bool IsSeekable() const override;
+  void NotifyDataArrived() override;
+  void NotifyDataRemoved() override;
+
+ private:
+  // Synchronous initialization.
+  bool InitInternal();
+
+  RefPtr<MediaResource> mSource;
+  RefPtr<MP3TrackDemuxer> mTrackDemuxer;
+};
+
+// The MP3 demuxer used to extract MPEG frames and side information out of
+// MPEG streams.
+class MP3TrackDemuxer : public MediaTrackDemuxer,
+                        public DecoderDoctorLifeLogger<MP3TrackDemuxer> {
+ public:
+  // Constructor, expecting a valid media resource.
+  explicit MP3TrackDemuxer(MediaResource* aSource);
+
+  // Initializes the track demuxer by reading the first frame for meta data.
+  // Returns initialization success state.
+  bool Init();
+
+  // Returns the total stream length if known, -1 otherwise.
+  int64_t StreamLength() const;
+
+  // Returns the estimated stream duration, or a 0-duration if unknown.
+  media::NullableTimeUnit Duration() const;
+
+  // Returns the estimated duration up to the given frame number,
+  // or a 0-duration if unknown.
+  media::TimeUnit Duration(int64_t aNumFrames) const;
+
+  // Returns the estimated current seek position time.
+  media::TimeUnit SeekPosition() const;
+
+  const FrameParser::Frame& LastFrame() const;
+  RefPtr<MediaRawData> DemuxSample();
+
+  const ID3Parser::ID3Header& ID3Header() const;
+  const FrameParser::VBRHeader& VBRInfo() const;
+
+  // MediaTrackDemuxer interface.
+  UniquePtr<TrackInfo> GetInfo() const override;
+  RefPtr<SeekPromise> Seek(const media::TimeUnit& aTime) override;
+  RefPtr<SamplesPromise> GetSamples(int32_t aNumSamples = 1) override;
+  void Reset() override;
+  RefPtr<SkipAccessPointPromise> SkipToNextRandomAccessPoint(
+      const media::TimeUnit& aTimeThreshold) override;
+  int64_t GetResourceOffset() const override;
+  media::TimeIntervals GetBuffered() override;
+  // Return the duration in frames of the encoder delay.
+  uint32_t EncoderDelayFrames() const;
+  // Return the duration  in frames of the padding.
+  uint32_t PaddingFrames() const;
+
+ private:
+  // Destructor.
+  ~MP3TrackDemuxer() = default;
+
+  // Fast approximate seeking to given time.
+  media::TimeUnit FastSeek(const media::TimeUnit& aTime);
+
+  // Seeks by scanning the stream up to the given time for more accurate
+  // results.
+  media::TimeUnit ScanUntil(const media::TimeUnit& aTime);
+
+  // Finds the first valid frame and returns its byte range if found
+  // or a null-byte range otherwise.
+  MediaByteRange FindFirstFrame();
+
+  // Finds the next valid frame and returns its byte range if found
+  // or a null-byte range otherwise.
+  MediaByteRange FindNextFrame();
+
+  // Skips the next frame given the provided byte range.
+  bool SkipNextFrame(const MediaByteRange& aRange);
+
+  // Returns the next MPEG frame, if available.
+  already_AddRefed<MediaRawData> GetNextFrame(const MediaByteRange& aRange);
+
+  // Updates post-read meta data.
+  void UpdateState(const MediaByteRange& aRange);
+
+  // Returns the estimated offset for the given frame index.
+  int64_t OffsetFromFrameIndex(int64_t aFrameIndex) const;
+
+  // Returns the estimated frame index for the given offset.
+  int64_t FrameIndexFromOffset(int64_t aOffset) const;
+
+  // Returns the estimated frame index for the given time.
+  int64_t FrameIndexFromTime(const media::TimeUnit& aTime) const;
+
+  // Reads aSize bytes into aBuffer from the source starting at aOffset.
+  // Returns the actual size read.
+  uint32_t Read(uint8_t* aBuffer, int64_t aOffset, uint32_t aSize);
+
+  // Returns the average frame length derived from the previously parsed frames.
+  double AverageFrameLength() const;
+
+  // Returns the number of frames reported by the header if it's valid. Nothing
+  // otherwise.
+  Maybe<uint32_t> ValidNumAudioFrames() const;
+
+  // Return the duration of the encoder delay.
+  media::TimeUnit EncoderDelay() const;
+
+  // Return the duration of the padding.
+  media::TimeUnit Padding() const;
+
+  // The (hopefully) MPEG resource.
+  MediaResourceIndex mSource;
+
+  // MPEG frame parser used to detect frames and extract side info.
+  FrameParser mParser;
+
+  // Whether we've locked onto a valid sequence of frames or not.
+  bool mFrameLock;
+
+  // Current byte offset in the source stream.
+  int64_t mOffset;
+
+  // Byte offset of the begin of the first frame, or 0 if none parsed yet.
+  int64_t mFirstFrameOffset;
+
+  // Total parsed frames.
+  uint64_t mNumParsedFrames;
+
+  // Current frame index.
+  int64_t mFrameIndex;
+
+  // Sum of parsed frames' lengths in bytes.
+  int64_t mTotalFrameLen;
+
+  // Samples per frame metric derived from frame headers or 0 if none available.
+  uint32_t mSamplesPerFrame;
+
+  // Samples per second metric derived from frame headers or 0 if none
+  // available.
+  uint32_t mSamplesPerSecond;
+
+  // Channel count derived from frame headers or 0 if none available.
+  uint32_t mChannels;
+
+  // Audio track config info.
+  UniquePtr<AudioInfo> mInfo;
+
+  // Number of frames to skip at the beginning
+  uint32_t mEncoderDelay = 0;
+  // Number of frames to skip at the end
+  uint32_t mEncoderPadding = 0;
+  int32_t mRemainingEncoderPadding = 0;
+  // End of stream has been found
+  bool mEOS = false;
+};
+
+}  // namespace mozilla
+
+#endif
diff --git a/dom/media/mp3/MP3FrameParser.cpp b/dom/media/mp3/MP3FrameParser.cpp
new file mode 100644
index 0000000000..9701aa2f8f
--- /dev/null
+++ b/dom/media/mp3/MP3FrameParser.cpp
@@ -0,0 +1,817 @@
+/* -*- 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 "MP3FrameParser.h"
+
+#include <algorithm>
+#include <inttypes.h>
+
+#include "TimeUnits.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/EndianUtils.h"
+#include "mozilla/ResultExtensions.h"
+#include "mozilla/ScopeExit.h"
+#include "VideoUtils.h"
+
+extern mozilla::LazyLogModule gMediaDemuxerLog;
+#define MP3LOG(msg, ...) \
+  MOZ_LOG(gMediaDemuxerLog, LogLevel::Debug, ("MP3Demuxer " msg, ##__VA_ARGS__))
+#define MP3LOGV(msg, ...)                      \
+  MOZ_LOG(gMediaDemuxerLog, LogLevel::Verbose, \
+          ("MP3Demuxer " msg, ##__VA_ARGS__))
+
+namespace mozilla {
+
+// FrameParser
+
+namespace frame_header {
+// FrameHeader mRaw byte offsets.
+static const int SYNC1 = 0;
+static const int SYNC2_VERSION_LAYER_PROTECTION = 1;
+static const int BITRATE_SAMPLERATE_PADDING_PRIVATE = 2;
+static const int CHANNELMODE_MODEEXT_COPY_ORIG_EMPH = 3;
+}  // namespace frame_header
+
+FrameParser::FrameParser() = default;
+
+void FrameParser::Reset() {
+  mID3Parser.Reset();
+  mFrame.Reset();
+}
+
+void FrameParser::ResetFrameData() {
+  mFrame.Reset();
+  mFirstFrame.Reset();
+  mPrevFrame.Reset();
+}
+
+void FrameParser::EndFrameSession() {
+  if (!mID3Parser.Header().IsValid()) {
+    // Reset ID3 tags only if we have not parsed a valid ID3 header yet.
+    mID3Parser.Reset();
+  }
+  mPrevFrame = mFrame;
+  mFrame.Reset();
+}
+
+const FrameParser::Frame& FrameParser::CurrentFrame() const { return mFrame; }
+
+const FrameParser::Frame& FrameParser::PrevFrame() const { return mPrevFrame; }
+
+const FrameParser::Frame& FrameParser::FirstFrame() const {
+  return mFirstFrame;
+}
+
+const ID3Parser::ID3Header& FrameParser::ID3Header() const {
+  return mID3Parser.Header();
+}
+
+uint32_t FrameParser::TotalID3HeaderSize() const {
+  uint32_t ID3v1Size = 0;
+  if (mID3v1MetadataFound) {
+    ID3v1Size = 128;
+  }
+  return ID3v1Size + mID3Parser.TotalHeadersSize();
+}
+
+const FrameParser::VBRHeader& FrameParser::VBRInfo() const {
+  return mVBRHeader;
+}
+
+Result<bool, nsresult> FrameParser::Parse(BufferReader* aReader,
+                                          uint32_t* aBytesToSkip) {
+  MOZ_ASSERT(aReader && aBytesToSkip);
+  *aBytesToSkip = 0;
+
+  if (ID3Parser::IsBufferStartingWithID3v1Tag(aReader)) {
+    // This is usually at the end of the file, and is always 128 bytes, that
+    // can simply be skipped.
+    aReader->Read(128);
+    *aBytesToSkip = 128;
+    mID3v1MetadataFound = true;
+    MP3LOGV("ID3v1 tag detected, skipping 128 bytes past the current buffer");
+    return false;
+  }
+
+  if (ID3Parser::IsBufferStartingWithID3Tag(aReader) && !mFirstFrame.Length()) {
+    // No MP3 frames have been parsed yet, look for ID3v2 headers at file begin.
+    // ID3v1 tags may only be at file end.
+    const size_t prevReaderOffset = aReader->Offset();
+    const uint32_t tagSize = mID3Parser.Parse(aReader);
+    if (!!tagSize) {
+      // ID3 tag found, skip past it.
+      const uint32_t skipSize = tagSize - ID3Parser::ID3Header::SIZE;
+
+      if (skipSize > aReader->Remaining()) {
+        // Skipping across the ID3v2 tag would take us past the end of the
+        // buffer, therefore we return immediately and let the calling function
+        // handle skipping the rest of the tag.
+        MP3LOGV(
+            "ID3v2 tag detected, size=%d,"
+            " needing to skip %zu bytes past the current buffer",
+            tagSize, skipSize - aReader->Remaining());
+        *aBytesToSkip = skipSize - aReader->Remaining();
+        return false;
+      }
+      MP3LOGV("ID3v2 tag detected, size=%d", tagSize);
+      aReader->Read(skipSize);
+    } else {
+      // No ID3v2 tag found, rewinding reader in order to search for a MPEG
+      // frame header.
+      aReader->Seek(prevReaderOffset);
+    }
+  }
+
+  for (auto res = aReader->ReadU8();
+       res.isOk() && !mFrame.ParseNext(res.unwrap()); res = aReader->ReadU8()) {
+  }
+
+  if (mFrame.Length()) {
+    // MP3 frame found.
+    if (!mFirstFrame.Length()) {
+      mFirstFrame = mFrame;
+    }
+    // Indicate success.
+    return true;
+  }
+  return false;
+}
+
+// FrameParser::Header
+
+FrameParser::FrameHeader::FrameHeader() { Reset(); }
+
+uint8_t FrameParser::FrameHeader::Sync1() const {
+  return mRaw[frame_header::SYNC1];
+}
+
+uint8_t FrameParser::FrameHeader::Sync2() const {
+  return 0x7 & mRaw[frame_header::SYNC2_VERSION_LAYER_PROTECTION] >> 5;
+}
+
+uint8_t FrameParser::FrameHeader::RawVersion() const {
+  return 0x3 & mRaw[frame_header::SYNC2_VERSION_LAYER_PROTECTION] >> 3;
+}
+
+uint8_t FrameParser::FrameHeader::RawLayer() const {
+  return 0x3 & mRaw[frame_header::SYNC2_VERSION_LAYER_PROTECTION] >> 1;
+}
+
+uint8_t FrameParser::FrameHeader::RawProtection() const {
+  return 0x1 & mRaw[frame_header::SYNC2_VERSION_LAYER_PROTECTION] >> 6;
+}
+
+uint8_t FrameParser::FrameHeader::RawBitrate() const {
+  return 0xF & mRaw[frame_header::BITRATE_SAMPLERATE_PADDING_PRIVATE] >> 4;
+}
+
+uint8_t FrameParser::FrameHeader::RawSampleRate() const {
+  return 0x3 & mRaw[frame_header::BITRATE_SAMPLERATE_PADDING_PRIVATE] >> 2;
+}
+
+uint8_t FrameParser::FrameHeader::Padding() const {
+  return 0x1 & mRaw[frame_header::BITRATE_SAMPLERATE_PADDING_PRIVATE] >> 1;
+}
+
+uint8_t FrameParser::FrameHeader::Private() const {
+  return 0x1 & mRaw[frame_header::BITRATE_SAMPLERATE_PADDING_PRIVATE];
+}
+
+uint8_t FrameParser::FrameHeader::RawChannelMode() const {
+  return 0x3 & mRaw[frame_header::CHANNELMODE_MODEEXT_COPY_ORIG_EMPH] >> 6;
+}
+
+uint32_t FrameParser::FrameHeader::Layer() const {
+  static const uint8_t LAYERS[4] = {0, 3, 2, 1};
+
+  return LAYERS[RawLayer()];
+}
+
+uint32_t FrameParser::FrameHeader::SampleRate() const {
+  // Sample rates - use [version][srate]
+  static const uint16_t SAMPLE_RATE[4][4] = {
+      // clang-format off
+    { 11025, 12000,  8000, 0 }, // MPEG 2.5
+    {     0,     0,     0, 0 }, // Reserved
+    { 22050, 24000, 16000, 0 }, // MPEG 2
+    { 44100, 48000, 32000, 0 }  // MPEG 1
+      // clang-format on
+  };
+
+  return SAMPLE_RATE[RawVersion()][RawSampleRate()];
+}
+
+uint32_t FrameParser::FrameHeader::Channels() const {
+  // 3 is single channel (mono), any other value is some variant of dual
+  // channel.
+  return RawChannelMode() == 3 ? 1 : 2;
+}
+
+uint32_t FrameParser::FrameHeader::SamplesPerFrame() const {
+  // Samples per frame - use [version][layer]
+  static const uint16_t FRAME_SAMPLE[4][4] = {
+      // clang-format off
+    // Layer     3     2     1       Version
+    {      0,  576, 1152,  384 }, // 2.5
+    {      0,    0,    0,    0 }, // Reserved
+    {      0,  576, 1152,  384 }, // 2
+    {      0, 1152, 1152,  384 }  // 1
+      // clang-format on
+  };
+
+  return FRAME_SAMPLE[RawVersion()][RawLayer()];
+}
+
+uint32_t FrameParser::FrameHeader::Bitrate() const {
+  // Bitrates - use [version][layer][bitrate]
+  static const uint16_t BITRATE[4][4][16] = {
+      // clang-format off
+    { // Version 2.5
+      { 0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 0 }, // Reserved
+      { 0,   8,  16,  24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160, 0 }, // Layer 3
+      { 0,   8,  16,  24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160, 0 }, // Layer 2
+      { 0,  32,  48,  56,  64,  80,  96, 112, 128, 144, 160, 176, 192, 224, 256, 0 }  // Layer 1
+    },
+    { // Reserved
+      { 0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 0 }, // Invalid
+      { 0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 0 }, // Invalid
+      { 0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 0 }, // Invalid
+      { 0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 0 }  // Invalid
+    },
+    { // Version 2
+      { 0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 0 }, // Reserved
+      { 0,   8,  16,  24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160, 0 }, // Layer 3
+      { 0,   8,  16,  24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160, 0 }, // Layer 2
+      { 0,  32,  48,  56,  64,  80,  96, 112, 128, 144, 160, 176, 192, 224, 256, 0 }  // Layer 1
+    },
+    { // Version 1
+      { 0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 0 }, // Reserved
+      { 0,  32,  40,  48,  56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, 0 }, // Layer 3
+      { 0,  32,  48,  56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, 384, 0 }, // Layer 2
+      { 0,  32,  64,  96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 0 }, // Layer 1
+    }
+      // clang-format on
+  };
+
+  return 1000 * BITRATE[RawVersion()][RawLayer()][RawBitrate()];
+}
+
+uint32_t FrameParser::FrameHeader::SlotSize() const {
+  // Slot size (MPEG unit of measurement) - use [layer]
+  static const uint8_t SLOT_SIZE[4] = {0, 1, 1, 4};  // Rsvd, 3, 2, 1
+
+  return SLOT_SIZE[RawLayer()];
+}
+
+bool FrameParser::FrameHeader::ParseNext(uint8_t c) {
+  if (!Update(c)) {
+    Reset();
+    if (!Update(c)) {
+      Reset();
+    }
+  }
+  return IsValid();
+}
+
+bool FrameParser::ID3v1MetadataFound() const { return mID3v1MetadataFound; }
+
+bool FrameParser::FrameHeader::IsValid(int aPos) const {
+  if (aPos >= SIZE) {
+    return true;
+  }
+  if (aPos == frame_header::SYNC1) {
+    return Sync1() == 0xFF;
+  }
+  if (aPos == frame_header::SYNC2_VERSION_LAYER_PROTECTION) {
+    return Sync2() == 7 && RawVersion() != 1 && Layer() == 3;
+  }
+  if (aPos == frame_header::BITRATE_SAMPLERATE_PADDING_PRIVATE) {
+    return RawBitrate() != 0xF && RawBitrate() != 0 && RawSampleRate() != 3;
+  }
+  return true;
+}
+
+bool FrameParser::FrameHeader::IsValid() const { return mPos >= SIZE; }
+
+void FrameParser::FrameHeader::Reset() { mPos = 0; }
+
+bool FrameParser::FrameHeader::Update(uint8_t c) {
+  if (mPos < SIZE) {
+    mRaw[mPos] = c;
+  }
+  return IsValid(mPos++);
+}
+
+// FrameParser::VBRHeader
+
+namespace vbr_header {
+static const char* TYPE_STR[3] = {"NONE", "XING", "VBRI"};
+static const uint32_t TOC_SIZE = 100;
+}  // namespace vbr_header
+
+FrameParser::VBRHeader::VBRHeader() : mType(NONE) {}
+
+FrameParser::VBRHeader::VBRHeaderType FrameParser::VBRHeader::Type() const {
+  return mType;
+}
+
+const Maybe<uint32_t>& FrameParser::VBRHeader::NumAudioFrames() const {
+  return mNumAudioFrames;
+}
+
+const Maybe<uint32_t>& FrameParser::VBRHeader::NumBytes() const {
+  return mNumBytes;
+}
+
+const Maybe<uint32_t>& FrameParser::VBRHeader::Scale() const { return mScale; }
+
+bool FrameParser::VBRHeader::IsTOCPresent() const {
+  // This doesn't use VBRI TOC
+  return !mTOC.empty() && mType != VBRI;
+}
+
+bool FrameParser::VBRHeader::IsValid() const { return mType != NONE; }
+
+bool FrameParser::VBRHeader::IsComplete() const {
+  return IsValid() && mNumAudioFrames.valueOr(0) > 0 && mNumBytes.valueOr(0) > 0
+      // We don't care about the scale for any computations here.
+      // && mScale < 101
+      ;
+}
+
+int64_t FrameParser::VBRHeader::Offset(media::TimeUnit aTime,
+                                       media::TimeUnit aDuration) const {
+  if (!IsTOCPresent()) {
+    return -1;
+  }
+
+  int64_t offset = -1;
+  if (mType == XING) {
+    // Constrain the duration percentage to [0, 99].
+    double percent = 100. * aTime.ToSeconds() / aDuration.ToSeconds();
+    const double durationPer = std::clamp(percent, 0., 99.);
+    double integer;
+    const double fractional = modf(durationPer, &integer);
+    size_t integerPer = AssertedCast<size_t>(integer);
+
+    MOZ_ASSERT(integerPer < mTOC.size());
+    offset = mTOC.at(integerPer);
+    if (fractional > 0.0 && integerPer + 1 < mTOC.size()) {
+      offset += AssertedCast<int64_t>(fractional) *
+                (mTOC.at(integerPer + 1) - offset);
+    }
+  }
+  // TODO: VBRI TOC seeking
+  MP3LOG("VBRHeader::Offset (%s): %f is at byte %" PRId64 "",
+         mType == XING ? "XING" : "VBRI", aTime.ToSeconds(), offset);
+
+  return offset;
+}
+
+Result<bool, nsresult> FrameParser::VBRHeader::ParseXing(BufferReader* aReader,
+                                                         size_t aFrameSize) {
+  static const uint32_t XING_TAG = BigEndian::readUint32("Xing");
+  static const uint32_t INFO_TAG = BigEndian::readUint32("Info");
+  static const uint32_t LAME_TAG = BigEndian::readUint32("LAME");
+  static const uint32_t LAVC_TAG = BigEndian::readUint32("Lavc");
+
+  enum Flags {
+    NUM_FRAMES = 0x01,
+    NUM_BYTES = 0x02,
+    TOC = 0x04,
+    VBR_SCALE = 0x08
+  };
+
+  MOZ_ASSERT(aReader);
+
+  // Seek backward to the original position before leaving this scope.
+  const size_t prevReaderOffset = aReader->Offset();
+  auto scopeExit = MakeScopeExit([&] { aReader->Seek(prevReaderOffset); });
+
+  // We have to search for the Xing header as its position can change.
+  for (auto res = aReader->PeekU32();
+       res.isOk() && res.unwrap() != XING_TAG && res.unwrap() != INFO_TAG;) {
+    aReader->Read(1);
+    res = aReader->PeekU32();
+  }
+
+  // Skip across the VBR header ID tag.
+  MOZ_TRY(aReader->ReadU32());
+  mType = XING;
+
+  uint32_t flags;
+  MOZ_TRY_VAR(flags, aReader->ReadU32());
+
+  if (flags & NUM_FRAMES) {
+    uint32_t frames;
+    MOZ_TRY_VAR(frames, aReader->ReadU32());
+    mNumAudioFrames = Some(frames);
+  }
+  if (flags & NUM_BYTES) {
+    uint32_t bytes;
+    MOZ_TRY_VAR(bytes, aReader->ReadU32());
+    mNumBytes = Some(bytes);
+  }
+  if (flags & TOC && aReader->Remaining() >= vbr_header::TOC_SIZE) {
+    if (!mNumBytes) {
+      // We don't have the stream size to calculate offsets, skip the TOC.
+      aReader->Read(vbr_header::TOC_SIZE);
+    } else {
+      mTOC.clear();
+      mTOC.reserve(vbr_header::TOC_SIZE);
+      uint8_t data;
+      for (size_t i = 0; i < vbr_header::TOC_SIZE; ++i) {
+        MOZ_TRY_VAR(data, aReader->ReadU8());
+        mTOC.push_back(
+            AssertedCast<uint32_t>(1.0f / 256.0f * data * mNumBytes.value()));
+      }
+    }
+  }
+  if (flags & VBR_SCALE) {
+    uint32_t scale;
+    MOZ_TRY_VAR(scale, aReader->ReadU32());
+    mScale = Some(scale);
+  }
+
+  uint32_t lameOrLavcTag;
+  MOZ_TRY_VAR(lameOrLavcTag, aReader->ReadU32());
+
+  if (lameOrLavcTag == LAME_TAG || lameOrLavcTag == LAVC_TAG) {
+    // Skip 17 bytes after the LAME tag:
+    // - http://gabriel.mp3-tech.org/mp3infotag.html
+    // - 5 bytes for the encoder short version string
+    // - 1 byte for the info tag revision + VBR method
+    // - 1 byte for the lowpass filter value
+    // - 8 bytes for the ReplayGain information
+    // - 1 byte for the encoding flags + ATH Type
+    // - 1 byte for the specified bitrate if ABR, else the minimal bitrate
+    if (!aReader->Read(17)) {
+      return mozilla::Err(NS_ERROR_FAILURE);
+    }
+
+    // The encoder delay is three bytes, for two 12-bits integers are the
+    // encoder delay and the padding.
+    const uint8_t* delayPadding = aReader->Read(3);
+    if (!delayPadding) {
+      return mozilla::Err(NS_ERROR_FAILURE);
+    }
+    mEncoderDelay =
+        uint32_t(delayPadding[0]) << 4 | (delayPadding[1] & 0xf0) >> 4;
+    mEncoderPadding = uint32_t(delayPadding[1] & 0x0f) << 8 | delayPadding[2];
+
+    constexpr uint16_t DEFAULT_DECODER_DELAY = 529;
+    mEncoderDelay += DEFAULT_DECODER_DELAY + aFrameSize;  // ignore first frame.
+    mEncoderPadding -= std::min(mEncoderPadding, DEFAULT_DECODER_DELAY);
+
+    MP3LOG("VBRHeader::ParseXing: LAME encoder delay section: delay: %" PRIu16
+           " frames, padding: %" PRIu16 " frames",
+           mEncoderDelay, mEncoderPadding);
+  }
+
+  return mType == XING;
+}
+
+template <typename T>
+int readAndConvertToInt(BufferReader* aReader) {
+  int value = AssertedCast<int>(aReader->ReadType<T>());
+  return value;
+}
+
+Result<bool, nsresult> FrameParser::VBRHeader::ParseVBRI(
+    BufferReader* aReader) {
+  static const uint32_t TAG = BigEndian::readUint32("VBRI");
+  static const uint32_t OFFSET = 32 + FrameParser::FrameHeader::SIZE;
+  static const uint32_t MIN_FRAME_SIZE = OFFSET + 26;
+
+  MOZ_ASSERT(aReader);
+  // ParseVBRI assumes that the ByteReader offset points to the beginning of a
+  // frame, therefore as a simple check, we look for the presence of a frame
+  // sync at that position.
+  auto sync = aReader->PeekU16();
+  if (sync.isOk()) {  // To avoid compiler complains 'set but unused'.
+    MOZ_ASSERT((sync.unwrap() & 0xFFE0) == 0xFFE0);
+  }
+
+  // Seek backward to the original position before leaving this scope.
+  const size_t prevReaderOffset = aReader->Offset();
+  auto scopeExit = MakeScopeExit([&] { aReader->Seek(prevReaderOffset); });
+
+  // VBRI have a fixed relative position, so let's check for it there.
+  if (aReader->Remaining() > MIN_FRAME_SIZE) {
+    aReader->Seek(prevReaderOffset + OFFSET);
+    uint32_t tag;
+    MOZ_TRY_VAR(tag, aReader->ReadU32());
+    if (tag == TAG) {
+      uint16_t vbriEncoderVersion, vbriEncoderDelay, vbriQuality;
+      uint32_t vbriBytes, vbriFrames;
+      uint16_t vbriSeekOffsetsTableSize, vbriSeekOffsetsScaleFactor,
+          vbriSeekOffsetsBytesPerEntry, vbriSeekOffsetsFramesPerEntry;
+      MOZ_TRY_VAR(vbriEncoderVersion, aReader->ReadU16());
+      MOZ_TRY_VAR(vbriEncoderDelay, aReader->ReadU16());
+      MOZ_TRY_VAR(vbriQuality, aReader->ReadU16());
+      MOZ_TRY_VAR(vbriBytes, aReader->ReadU32());
+      MOZ_TRY_VAR(vbriFrames, aReader->ReadU32());
+      MOZ_TRY_VAR(vbriSeekOffsetsTableSize, aReader->ReadU16());
+      MOZ_TRY_VAR(vbriSeekOffsetsScaleFactor, aReader->ReadU32());
+      MOZ_TRY_VAR(vbriSeekOffsetsBytesPerEntry, aReader->ReadU16());
+      MOZ_TRY_VAR(vbriSeekOffsetsFramesPerEntry, aReader->ReadU16());
+
+      mTOC.reserve(vbriSeekOffsetsTableSize + 1);
+
+      int (*readFunc)(BufferReader*) = nullptr;
+      switch (vbriSeekOffsetsBytesPerEntry) {
+        case 1:
+          readFunc = &readAndConvertToInt<uint8_t>;
+          break;
+        case 2:
+          readFunc = &readAndConvertToInt<int16_t>;
+          break;
+        case 4:
+          readFunc = &readAndConvertToInt<int32_t>;
+          break;
+        case 8:
+          readFunc = &readAndConvertToInt<int64_t>;
+          break;
+        default:
+          MP3LOG("Unhandled vbriSeekOffsetsBytesPerEntry size of %hd",
+                 vbriSeekOffsetsBytesPerEntry);
+          break;
+      }
+      for (uint32_t i = 0; readFunc && i < vbriSeekOffsetsTableSize; i++) {
+        int entry = readFunc(aReader);
+        mTOC.push_back(entry * vbriSeekOffsetsScaleFactor);
+      }
+      MP3LOG(
+          "Header::Parse found valid  header: EncoderVersion=%hu "
+          "EncoderDelay=%hu "
+          "Quality=%hu "
+          "Bytes=%u "
+          "Frames=%u "
+          "SeekOffsetsTableSize=%u "
+          "SeekOffsetsScaleFactor=%hu "
+          "SeekOffsetsBytesPerEntry=%hu "
+          "SeekOffsetsFramesPerEntry=%hu",
+          vbriEncoderVersion, vbriEncoderDelay, vbriQuality, vbriBytes,
+          vbriFrames, vbriSeekOffsetsTableSize, vbriSeekOffsetsScaleFactor,
+          vbriSeekOffsetsBytesPerEntry, vbriSeekOffsetsFramesPerEntry);
+      // Adjust the number of frames so it's counted the same way as in the XING
+      // header
+      if (vbriFrames < 1) {
+        return false;
+      }
+      mNumAudioFrames = Some(vbriFrames - 1);
+      mNumBytes = Some(vbriBytes);
+      mEncoderDelay = vbriEncoderDelay;
+      mVBRISeekOffsetsFramesPerEntry = vbriSeekOffsetsFramesPerEntry;
+      MP3LOG("TOC:");
+      for (auto entry : mTOC) {
+        MP3LOG("%" PRId64, entry);
+      }
+
+      mType = VBRI;
+      return true;
+    }
+  }
+  return false;
+}
+
+bool FrameParser::VBRHeader::Parse(BufferReader* aReader, size_t aFrameSize) {
+  auto res = std::make_pair(ParseVBRI(aReader), ParseXing(aReader, aFrameSize));
+  const bool rv = (res.first.isOk() && res.first.unwrap()) ||
+                  (res.second.isOk() && res.second.unwrap());
+  if (rv) {
+    MP3LOG(
+        "VBRHeader::Parse found valid VBR/CBR header: type=%s"
+        " NumAudioFrames=%u NumBytes=%u Scale=%u TOC-size=%zu Delay=%u",
+        vbr_header::TYPE_STR[Type()], NumAudioFrames().valueOr(0),
+        NumBytes().valueOr(0), Scale().valueOr(0), mTOC.size(), mEncoderDelay);
+  }
+  return rv;
+}
+
+// FrameParser::Frame
+
+void FrameParser::Frame::Reset() { mHeader.Reset(); }
+
+uint32_t FrameParser::Frame::Length() const {
+  if (!mHeader.IsValid() || !mHeader.SampleRate()) {
+    return 0;
+  }
+
+  const uint32_t bitsPerSample = mHeader.SamplesPerFrame() / 8;
+  const uint32_t frameLen =
+      bitsPerSample * mHeader.Bitrate() / mHeader.SampleRate() +
+      mHeader.Padding() * mHeader.SlotSize();
+  return frameLen;
+}
+
+bool FrameParser::Frame::ParseNext(uint8_t c) { return mHeader.ParseNext(c); }
+
+const FrameParser::FrameHeader& FrameParser::Frame::Header() const {
+  return mHeader;
+}
+
+bool FrameParser::ParseVBRHeader(BufferReader* aReader) {
+  return mVBRHeader.Parse(aReader, CurrentFrame().Header().SamplesPerFrame());
+}
+
+// ID3Parser
+
+// Constants
+namespace id3_header {
+static const int ID_LEN = 3;
+static const int VERSION_LEN = 2;
+static const int FLAGS_LEN = 1;
+static const int SIZE_LEN = 4;
+
+static const int ID_END = ID_LEN;
+static const int VERSION_END = ID_END + VERSION_LEN;
+static const int FLAGS_END = VERSION_END + FLAGS_LEN;
+static const int SIZE_END = FLAGS_END + SIZE_LEN;
+
+static const uint8_t ID[ID_LEN] = {'I', 'D', '3'};
+static const uint8_t IDv1[ID_LEN] = {'T', 'A', 'G'};
+
+static const uint8_t MIN_MAJOR_VER = 2;
+static const uint8_t MAX_MAJOR_VER = 4;
+}  // namespace id3_header
+
+bool ID3Parser::IsBufferStartingWithID3v1Tag(BufferReader* aReader) {
+  mozilla::Result<uint32_t, nsresult> res = aReader->PeekU24();
+  if (res.isErr()) {
+    return false;
+  }
+  // If buffer starts with ID3v1 tag, `rv` would be reverse and its content
+  // should be '3' 'D' 'I' from the lowest bit.
+  uint32_t rv = res.unwrap();
+  for (int idx = id3_header::ID_LEN - 1; idx >= 0; idx--) {
+    if ((rv & 0xff) != id3_header::IDv1[idx]) {
+      return false;
+    }
+    rv = rv >> 8;
+  }
+  return true;
+}
+
+/* static */
+bool ID3Parser::IsBufferStartingWithID3Tag(BufferReader* aReader) {
+  mozilla::Result<uint32_t, nsresult> res = aReader->PeekU24();
+  if (res.isErr()) {
+    return false;
+  }
+  // If buffer starts with ID3v2 tag, `rv` would be reverse and its content
+  // should be '3' 'D' 'I' from the lowest bit.
+  uint32_t rv = res.unwrap();
+  for (int idx = id3_header::ID_LEN - 1; idx >= 0; idx--) {
+    if ((rv & 0xff) != id3_header::ID[idx]) {
+      return false;
+    }
+    rv = rv >> 8;
+  }
+  return true;
+}
+
+uint32_t ID3Parser::Parse(BufferReader* aReader) {
+  MOZ_ASSERT(aReader);
+  MOZ_ASSERT(ID3Parser::IsBufferStartingWithID3Tag(aReader));
+
+  if (!mHeader.HasSizeBeenSet()) {
+    return ParseInternal(aReader);
+  }
+
+  // Encounter another possible ID3 header, if that is valid then we would use
+  // it and save the size of previous one in order to report the size of all ID3
+  // headers together in `TotalHeadersSize()`.
+  ID3Header prevHeader = mHeader;
+  mHeader.Reset();
+  uint32_t size = ParseInternal(aReader);
+  if (!size) {
+    // next ID3 is invalid, so revert the header.
+    mHeader = prevHeader;
+    return size;
+  }
+
+  mFormerID3Size += prevHeader.TotalTagSize();
+  return size;
+}
+
+uint32_t ID3Parser::ParseInternal(BufferReader* aReader) {
+  for (auto res = aReader->ReadU8();
+       res.isOk() && !mHeader.ParseNext(res.unwrap());
+       res = aReader->ReadU8()) {
+  }
+  return mHeader.TotalTagSize();
+}
+
+void ID3Parser::Reset() {
+  mHeader.Reset();
+  mFormerID3Size = 0;
+}
+
+uint32_t ID3Parser::TotalHeadersSize() const {
+  return mHeader.TotalTagSize() + mFormerID3Size;
+}
+
+const ID3Parser::ID3Header& ID3Parser::Header() const { return mHeader; }
+
+// ID3Parser::Header
+
+ID3Parser::ID3Header::ID3Header() { Reset(); }
+
+void ID3Parser::ID3Header::Reset() {
+  mSize.reset();
+  mPos = 0;
+}
+
+uint8_t ID3Parser::ID3Header::MajorVersion() const {
+  return mRaw[id3_header::ID_END];
+}
+
+uint8_t ID3Parser::ID3Header::MinorVersion() const {
+  return mRaw[id3_header::ID_END + 1];
+}
+
+uint8_t ID3Parser::ID3Header::Flags() const {
+  return mRaw[id3_header::FLAGS_END - id3_header::FLAGS_LEN];
+}
+
+uint32_t ID3Parser::ID3Header::Size() const {
+  if (!IsValid() || !mSize) {
+    return 0;
+  }
+  return *mSize;
+}
+
+bool ID3Parser::ID3Header::HasSizeBeenSet() const { return !!mSize; }
+
+uint8_t ID3Parser::ID3Header::FooterSize() const {
+  if (Flags() & (1 << 4)) {
+    return SIZE;
+  }
+  return 0;
+}
+
+uint32_t ID3Parser::ID3Header::TotalTagSize() const {
+  if (IsValid()) {
+    // Header found, return total tag size.
+    return ID3Header::SIZE + Size() + FooterSize();
+  }
+  return 0;
+}
+
+bool ID3Parser::ID3Header::ParseNext(uint8_t c) {
+  if (!Update(c)) {
+    Reset();
+    if (!Update(c)) {
+      Reset();
+    }
+  }
+  return IsValid();
+}
+
+bool ID3Parser::ID3Header::IsValid(int aPos) const {
+  if (aPos >= SIZE) {
+    return true;
+  }
+  const uint8_t c = mRaw[aPos];
+  switch (aPos) {
+    case 0:
+    case 1:
+    case 2:
+      // Expecting "ID3".
+      return id3_header::ID[aPos] == c;
+    case 3:
+      return MajorVersion() >= id3_header::MIN_MAJOR_VER &&
+             MajorVersion() <= id3_header::MAX_MAJOR_VER;
+    case 4:
+      return MinorVersion() < 0xFF;
+    case 5:
+      // Validate flags for supported versions, see bug 949036.
+      return ((0xFF >> MajorVersion()) & c) == 0;
+    case 6:
+    case 7:
+    case 8:
+    case 9:
+      return c < 0x80;
+  }
+  return true;
+}
+
+bool ID3Parser::ID3Header::IsValid() const { return mPos >= SIZE; }
+
+bool ID3Parser::ID3Header::Update(uint8_t c) {
+  if (mPos >= id3_header::SIZE_END - id3_header::SIZE_LEN &&
+      mPos < id3_header::SIZE_END) {
+    uint32_t tmp = mSize.valueOr(0) << 7;
+    mSize = Some(tmp | c);
+  }
+  if (mPos < SIZE) {
+    mRaw[mPos] = c;
+  }
+  return IsValid(mPos++);
+}
+
+}  // namespace mozilla
diff --git a/dom/media/mp3/MP3FrameParser.h b/dom/media/mp3/MP3FrameParser.h
new file mode 100644
index 0000000000..d0d7a372d2
--- /dev/null
+++ b/dom/media/mp3/MP3FrameParser.h
@@ -0,0 +1,374 @@
+/* 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/. */
+
+#ifndef MP3_FRAME_PARSER_H_
+#define MP3_FRAME_PARSER_H_
+
+#include <vector>
+
+#include "mozilla/Maybe.h"
+#include "mozilla/Result.h"
+#include "BufferReader.h"
+
+namespace mozilla {
+
+// ID3 header parser state machine used by FrameParser.
+// The header contains the following format (one byte per term):
+// 'I' 'D' '3' MajorVersion MinorVersion Flags Size1 Size2 Size3 Size4
+// For more details see https://id3.org/id3v2.4.0-structure
+class ID3Parser {
+ public:
+  // Holds the ID3 header and its parsing state.
+  class ID3Header {
+   public:
+    // The header size is static, see class comment.
+    static const int SIZE = 10;
+    static const int ID3v1_SIZE = 128;
+
+    // Constructor.
+    ID3Header();
+
+    // Resets the state to allow for a new parsing session.
+    void Reset();
+
+    // The ID3 tags are versioned like this: ID3vMajorVersion.MinorVersion.
+    uint8_t MajorVersion() const;
+    uint8_t MinorVersion() const;
+
+    // The ID3 flags field.
+    uint8_t Flags() const;
+
+    // The derived size based on the provided size fields.
+    uint32_t Size() const;
+
+    // To see whether we have parsed the value of the size from header.
+    bool HasSizeBeenSet() const;
+
+    // Returns the size of an ID3v2.4 footer if present and zero otherwise.
+    uint8_t FooterSize() const;
+
+    // The total size of the ID3 tag including header/footer, or zero if
+    // none has been found.
+    uint32_t TotalTagSize() const;
+
+    // Returns whether the parsed data is a valid ID3 header up to the given
+    // byte position.
+    bool IsValid(int aPos) const;
+
+    // Returns whether the parsed data is a complete and valid ID3 header.
+    bool IsValid() const;
+
+    // Parses the next provided byte.
+    // Returns whether the byte creates a valid sequence up to this point.
+    bool ParseNext(uint8_t c);
+
+   private:
+    // Updates the parser state machine with the provided next byte.
+    // Returns whether the provided byte is a valid next byte in the sequence.
+    bool Update(uint8_t c);
+
+    // The currently parsed byte sequence.
+    uint8_t mRaw[SIZE] = {};
+
+    // The derived size as provided by the size fields.
+    // The header size fields holds a 4 byte sequence with each MSB set to 0,
+    // this bits need to be ignored when deriving the actual size.
+    Maybe<uint32_t> mSize;
+
+    // The current byte position in the parsed sequence. Reset via Reset and
+    // incremented via Update.
+    int mPos = 0;
+  };
+
+  // Check if the buffer is starting with ID3v2 tag.
+  static bool IsBufferStartingWithID3Tag(BufferReader* aReader);
+  // Similarly, if the buffer is starting with ID3v1 tag.
+  static bool IsBufferStartingWithID3v1Tag(BufferReader* aReader);
+
+  // Returns the parsed ID3 header. Note: check for validity.
+  const ID3Header& Header() const;
+
+  // Returns the size of all parsed ID3 headers.
+  uint32_t TotalHeadersSize() const;
+
+  // Parses contents of given BufferReader for a valid ID3v2 header.
+  // Returns the parsed ID3v2 tag size if successful and zero otherwise.
+  uint32_t Parse(BufferReader* aReader);
+
+  // Resets the state to allow for a new parsing session.
+  void Reset();
+
+ private:
+  uint32_t ParseInternal(BufferReader* aReader);
+
+  // The currently parsed ID3 header. Reset via Reset, updated via Parse.
+  ID3Header mHeader;
+  // If a file contains multiple ID3 headers, then we would only select the
+  // latest one, but keep the size of former abandoned in order to return the
+  // correct size offset.
+  uint32_t mFormerID3Size = 0;
+};
+
+// MPEG audio frame parser.
+// The MPEG frame header has the following format (one bit per character):
+// 11111111 111VVLLC BBBBSSPR MMEETOHH
+// {   sync   } - 11 sync bits
+//   VV         - MPEG audio version ID (0->2.5, 1->reserved, 2->2, 3->1)
+//   LL         - Layer description (0->reserved, 1->III, 2->II, 3->I)
+//   C          - CRC protection bit (0->protected, 1->not protected)
+//   BBBB       - Bitrate index (see table in implementation)
+//   SS         - Sampling rate index (see table in implementation)
+//   P          - Padding bit (0->not padded, 1->padded by 1 slot size)
+//   R          - Private bit (ignored)
+//   MM         - Channel mode (0->stereo, 1->joint stereo, 2->dual channel,
+//                3->single channel)
+//   EE         - Mode extension for joint stereo (ignored)
+//   T          - Copyright (0->disabled, 1->enabled)
+//   O          - Original (0->copy, 1->original)
+//   HH         - Emphasis (0->none, 1->50/15 ms, 2->reserved, 3->CCIT J.17)
+class FrameParser {
+ public:
+  // Holds the frame header and its parsing state.
+  class FrameHeader {
+   public:
+    // The header size is static, see class comments.
+    static const int SIZE = 4;
+
+    // Constructor.
+    FrameHeader();
+
+    // Raw field access, see class comments for details.
+    uint8_t Sync1() const;
+    uint8_t Sync2() const;
+    uint8_t RawVersion() const;
+    uint8_t RawLayer() const;
+    uint8_t RawProtection() const;
+    uint8_t RawBitrate() const;
+    uint8_t RawSampleRate() const;
+    uint8_t Padding() const;
+    uint8_t Private() const;
+    uint8_t RawChannelMode() const;
+
+    // Sampling rate frequency in Hz.
+    uint32_t SampleRate() const;
+
+    // Number of audio channels.
+    uint32_t Channels() const;
+
+    // Samples per frames, static depending on MPEG version and layer.
+    uint32_t SamplesPerFrame() const;
+
+    // Slot size used for padding, static depending on MPEG layer.
+    uint32_t SlotSize() const;
+
+    // Bitrate in kbps, can vary between frames.
+    uint32_t Bitrate() const;
+
+    // MPEG layer (0->invalid, 1->I, 2->II, 3->III).
+    uint32_t Layer() const;
+
+    // Returns whether the parsed data is a valid frame header up to the given
+    // byte position.
+    bool IsValid(const int aPos) const;
+
+    // Returns whether the parsed data is a complete and valid frame header.
+    bool IsValid() const;
+
+    // Resets the state to allow for a new parsing session.
+    void Reset();
+
+    // Parses the next provided byte.
+    // Returns whether the byte creates a valid sequence up to this point.
+    bool ParseNext(const uint8_t c);
+
+   private:
+    // Updates the parser state machine with the provided next byte.
+    // Returns whether the provided byte is a valid next byte in the sequence.
+    bool Update(const uint8_t c);
+
+    // The currently parsed byte sequence.
+    uint8_t mRaw[SIZE] = {};
+
+    // The current byte position in the parsed sequence. Reset via Reset and
+    // incremented via Update.
+    int mPos = 0;
+  };
+
+  // VBR frames may contain Xing or VBRI headers for additional info, we use
+  // this class to parse them and access this info.
+  class VBRHeader {
+   public:
+    // Synchronize with vbr_header TYPE_STR on change.
+    enum VBRHeaderType { NONE = 0, XING, VBRI };
+
+    // Constructor.
+    VBRHeader();
+
+    // Returns the parsed VBR header type, or NONE if no valid header found.
+    VBRHeaderType Type() const;
+
+    // Returns the total number of audio frames (excluding the VBR header frame)
+    // expected in the stream/file.
+    const Maybe<uint32_t>& NumAudioFrames() const;
+
+    // Returns the expected size of the stream.
+    const Maybe<uint32_t>& NumBytes() const;
+
+    // Returns the VBR scale factor (0: best quality, 100: lowest quality).
+    const Maybe<uint32_t>& Scale() const;
+
+    // Returns true iff Xing/Info TOC (table of contents) is present.
+    bool IsTOCPresent() const;
+
+    // Returns whether the header is valid (type XING or VBRI).
+    bool IsValid() const;
+
+    // Returns whether the header is valid and contains reasonable non-zero
+    // field values.
+    bool IsComplete() const;
+
+    // Returns the byte offset for the given duration percentage as a factor
+    // (0: begin, 1.0: end).
+    int64_t Offset(media::TimeUnit aTime, media::TimeUnit aDuration) const;
+
+    // Parses contents of given ByteReader for a valid VBR header.
+    // The offset of the passed ByteReader needs to point to an MPEG frame
+    // begin, as a VBRI-style header is searched at a fixed offset relative to
+    // frame begin. Returns whether a valid VBR header was found in the range.
+    bool Parse(BufferReader* aReader, size_t aFrameSize);
+
+    uint32_t EncoderDelay() const { return mEncoderDelay; }
+    uint32_t EncoderPadding() const { return mEncoderPadding; }
+
+   private:
+    // Parses contents of given ByteReader for a valid Xing header.
+    // The initial ByteReader offset will be preserved.
+    // Returns whether a valid Xing header was found in the range.
+    Result<bool, nsresult> ParseXing(BufferReader* aReader, size_t aFrameSize);
+
+    // Parses contents of given ByteReader for a valid VBRI header.
+    // The initial ByteReader offset will be preserved. It also needs to point
+    // to the beginning of a valid MPEG frame, as VBRI headers are searched
+    // at a fixed offset relative to frame begin.
+    // Returns whether a valid VBRI header was found in the range.
+    Result<bool, nsresult> ParseVBRI(BufferReader* aReader);
+
+    // The total number of frames expected as parsed from a VBR header.
+    Maybe<uint32_t> mNumAudioFrames;
+
+    // The total number of bytes expected in the stream.
+    Maybe<uint32_t> mNumBytes;
+
+    // The VBR scale factor.
+    Maybe<uint32_t> mScale;
+
+    // The TOC table mapping duration percentage to byte offset.
+    std::vector<int64_t> mTOC;
+
+    // The detected VBR header type.
+    VBRHeaderType mType;
+
+    uint16_t mVBRISeekOffsetsFramesPerEntry = 0;
+
+    // Delay and padding values found in the LAME header. The encoder delay is a
+    // number of frames that has to be skipped at the beginning of the stream,
+    // encoder padding is a number of frames that needs to be ignored in the
+    // last packet.
+    uint16_t mEncoderDelay = 0;
+    uint16_t mEncoderPadding = 0;
+  };
+
+  // Frame meta container used to parse and hold a frame header and side info.
+  class Frame {
+   public:
+    // Returns the length of the frame excluding the header in bytes.
+    uint32_t Length() const;
+
+    // Returns the parsed frame header.
+    const FrameHeader& Header() const;
+
+    // Resets the frame header and data.
+    void Reset();
+
+    // Parses the next provided byte.
+    // Returns whether the byte creates a valid sequence up to this point.
+    bool ParseNext(uint8_t c);
+
+   private:
+    // The currently parsed frame header.
+    FrameHeader mHeader;
+  };
+
+  // Constructor.
+  FrameParser();
+
+  // Returns the currently parsed frame. Reset via Reset or EndFrameSession.
+  const Frame& CurrentFrame() const;
+
+  // Returns the previously parsed frame. Reset via Reset.
+  const Frame& PrevFrame() const;
+
+  // Returns the first parsed frame. Reset via Reset.
+  const Frame& FirstFrame() const;
+
+  // Returns the parsed ID3 header. Note: check for validity.
+  const ID3Parser::ID3Header& ID3Header() const;
+
+  // Returns whether ID3 metadata have been found, at the end of the file.
+  bool ID3v1MetadataFound() const;
+
+  // Returns the size of all parsed ID3 headers.
+  uint32_t TotalID3HeaderSize() const;
+
+  // Returns the parsed VBR header info. Note: check for validity by type.
+  const VBRHeader& VBRInfo() const;
+
+  // Resets the parser.
+  void Reset();
+
+  // Resets all frame data, but not the ID3Header.
+  // Don't use between frames as first frame data is reset.
+  void ResetFrameData();
+
+  // Clear the last parsed frame to allow for next frame parsing, i.e.:
+  // - sets PrevFrame to CurrentFrame
+  // - resets the CurrentFrame
+  // - resets ID3Header if no valid header was parsed yet
+  void EndFrameSession();
+
+  // Parses contents of given BufferReader for a valid frame header and returns
+  // true if one was found. After returning, the variable passed to
+  // 'aBytesToSkip' holds the amount of bytes to be skipped (if any) in order to
+  // jump across a large ID3v2 tag spanning multiple buffers.
+  Result<bool, nsresult> Parse(BufferReader* aReader, uint32_t* aBytesToSkip);
+
+  // Parses contents of given BufferReader for a valid VBR header.
+  // The offset of the passed BufferReader needs to point to an MPEG frame
+  // begin, as a VBRI-style header is searched at a fixed offset relative to
+  // frame begin. Returns whether a valid VBR header was found.
+  bool ParseVBRHeader(BufferReader* aReader);
+
+ private:
+  // ID3 header parser.
+  ID3Parser mID3Parser;
+
+  // VBR header parser.
+  VBRHeader mVBRHeader;
+
+  // We keep the first parsed frame around for static info access, the
+  // previously parsed frame for debugging and the currently parsed frame.
+  Frame mFirstFrame;
+  Frame mFrame;
+  Frame mPrevFrame;
+  // If this is true, ID3v1 metadata have been found at the end of the file, and
+  // must be sustracted from the stream size in order to compute the stream
+  // duration, when computing the duration of a CBR file based on its length in
+  // bytes. This means that the duration can change at the moment we reach the
+  // end of the file.
+  bool mID3v1MetadataFound = false;
+};
+
+}  // namespace mozilla
+
+#endif
diff --git a/dom/media/mp3/moz.build b/dom/media/mp3/moz.build
new file mode 100644
index 0000000000..70031cc2b4
--- /dev/null
+++ b/dom/media/mp3/moz.build
@@ -0,0 +1,22 @@
+# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+EXPORTS += [
+    "MP3Decoder.h",
+    "MP3Demuxer.h",
+    "MP3FrameParser.h",
+]
+
+UNIFIED_SOURCES += [
+    "MP3Decoder.cpp",
+    "MP3Demuxer.cpp",
+    "MP3FrameParser.cpp",
+]
+
+FINAL_LIBRARY = "xul"
+
+# Add libFuzzer configuration directives
+include("/tools/fuzzing/libfuzzer-config.mozbuild")