Adding upstream version 110.0.1.upstream/110.0.1upstream

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

7 files changed, 1554 insertions, 0 deletions

diff --git a/dom/media/flac/FlacDecoder.cpp b/dom/media/flac/FlacDecoder.cpp
new file mode 100644
index 0000000000..2f205c9aae
--- /dev/null
+++ b/dom/media/flac/FlacDecoder.cpp
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FlacDecoder.h"
+#include "MediaContainerType.h"
+#include "mozilla/StaticPrefs_media.h"
+
+namespace mozilla {
+
+/* static */
+bool FlacDecoder::IsEnabled() {
+#ifdef MOZ_FFVPX
+  return StaticPrefs::media_flac_enabled();
+#else
+  return false;
+#endif
+}
+
+/* static */
+bool FlacDecoder::IsSupportedType(const MediaContainerType& aContainerType) {
+  return IsEnabled() &&
+         (aContainerType.Type() == MEDIAMIMETYPE("audio/flac") ||
+          aContainerType.Type() == MEDIAMIMETYPE("audio/x-flac") ||
+          aContainerType.Type() == MEDIAMIMETYPE("application/x-flac"));
+}
+
+/* static */
+nsTArray<UniquePtr<TrackInfo>> FlacDecoder::GetTracksInfo(
+    const MediaContainerType& aType) {
+  nsTArray<UniquePtr<TrackInfo>> tracks;
+  if (!IsSupportedType(aType)) {
+    return tracks;
+  }
+
+  tracks.AppendElement(
+      CreateTrackInfoWithMIMETypeAndContainerTypeExtraParameters(
+          "audio/flac"_ns, aType));
+
+  return tracks;
+}
+
+}  // namespace mozilla
diff --git a/dom/media/flac/FlacDecoder.h b/dom/media/flac/FlacDecoder.h
new file mode 100644
index 0000000000..f40ae6c31a
--- /dev/null
+++ b/dom/media/flac/FlacDecoder.h
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef FLAC_DECODER_H_
+#define FLAC_DECODER_H_
+
+#include "mozilla/UniquePtr.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+class MediaContainerType;
+class TrackInfo;
+
+class FlacDecoder {
+ public:
+  // Returns true if the Flac backend is pref'ed 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  // !FLAC_DECODER_H_
diff --git a/dom/media/flac/FlacDemuxer.cpp b/dom/media/flac/FlacDemuxer.cpp
new file mode 100644
index 0000000000..d8873c565e
--- /dev/null
+++ b/dom/media/flac/FlacDemuxer.cpp
@@ -0,0 +1,1027 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FlacDemuxer.h"
+
+#include "mozilla/Maybe.h"
+#include "BitReader.h"
+#include "prenv.h"
+#include "FlacFrameParser.h"
+#include "VideoUtils.h"
+#include "TimeUnits.h"
+
+extern mozilla::LazyLogModule gMediaDemuxerLog;
+#define LOG(msg, ...) \
+  DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Debug, msg, ##__VA_ARGS__)
+#define LOGV(msg, ...) \
+  DDMOZ_LOG(gMediaDemuxerLog, LogLevel::Verbose, msg, ##__VA_ARGS__)
+
+using namespace mozilla::media;
+
+namespace mozilla {
+namespace flac {
+
+// flac::FrameHeader - Holds the flac frame header and its parsing
+// state.
+
+class FrameHeader {
+ public:
+  const AudioInfo& Info() const { return mInfo; }
+
+  uint32_t Size() const { return mSize; }
+
+  bool IsValid() const { return mValid; }
+
+  // Return the index (in samples) from the beginning of the track.
+  int64_t Index() const { return mIndex; }
+
+  // Parse the current packet and check that it made a valid flac frame header.
+  // From https://xiph.org/flac/format.html#frame_header
+  // A valid header is one that can be decoded without error and that has a
+  // valid CRC.
+  bool Parse(const uint8_t* aPacket, size_t aBytes) {
+    BitReader br(aPacket, aBytes * 8);
+
+    // Frame sync code.
+    if ((br.ReadBits(15) & 0x7fff) != 0x7ffc) {
+      return false;
+    }
+
+    // Variable block size stream code.
+    mVariableBlockSize = br.ReadBit();
+
+    // Block size and sample rate codes.
+    int bs_code = br.ReadBits(4);
+    int sr_code = br.ReadBits(4);
+
+    // Channels and decorrelation.
+    uint32_t ch_mode = br.ReadBits(4);
+    if (ch_mode < FLAC_MAX_CHANNELS) {
+      mInfo.mChannels = ch_mode + 1;
+    } else if (ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) {
+      // This is a special flac channels, we can't handle those yet. Treat it
+      // as stereo.
+      mInfo.mChannels = 2;
+    } else {
+      // invalid channel mode
+      return false;
+    }
+
+    // Bits per sample.
+    int bps_code = br.ReadBits(3);
+    if (bps_code == 3 || bps_code == 7) {
+      // Invalid sample size code.
+      return false;
+    }
+    mInfo.mBitDepth = FlacSampleSizeTable[bps_code];
+
+    // Reserved bit, must be 0.
+    if (br.ReadBit()) {
+      // Broken stream, invalid padding.
+      return false;
+    }
+
+    // Sample or frame count.
+    uint64_t frame_or_sample_num = br.ReadUTF8();
+    if (frame_or_sample_num == UINT64_MAX) {
+      // Sample/frame number invalid.
+      return false;
+    }
+
+    // Blocksize
+    if (bs_code == 0) {
+      // reserved blocksize code
+      return false;
+    } else if (bs_code == 6) {
+      mBlocksize = br.ReadBits(8) + 1;
+    } else if (bs_code == 7) {
+      mBlocksize = br.ReadBits(16) + 1;
+    } else {
+      mBlocksize = FlacBlocksizeTable[bs_code];
+    }
+
+    // The sample index is either:
+    // 1- coded sample number if blocksize is variable or
+    // 2- coded frame number if blocksize is known.
+    // A frame is made of Blocksize sample.
+    mIndex = mVariableBlockSize ? frame_or_sample_num
+                                : frame_or_sample_num * mBlocksize;
+    mFrameOrSampleNum = static_cast<uint64_t>(frame_or_sample_num);
+
+    // Sample rate.
+    if (sr_code < 12) {
+      mInfo.mRate = FlacSampleRateTable[sr_code];
+    } else if (sr_code == 12) {
+      mInfo.mRate = br.ReadBits(8) * 1000;
+    } else if (sr_code == 13) {
+      mInfo.mRate = br.ReadBits(16);
+    } else if (sr_code == 14) {
+      mInfo.mRate = br.ReadBits(16) * 10;
+    } else {
+      // Illegal sample rate code.
+      return false;
+    }
+
+    // Header CRC-8 check.
+    uint8_t crc = 0;
+    for (uint32_t i = 0; i < br.BitCount() / 8; i++) {
+      crc = CRC8Table[crc ^ aPacket[i]];
+    }
+    mValid =
+#ifdef FUZZING
+        true;
+#else
+        crc == br.ReadBits(8);
+#endif
+    mSize = br.BitCount() / 8;
+
+    if (mValid) {
+      // Set the mimetype to make it a valid AudioInfo.
+      mInfo.mMimeType = "audio/flac";
+      // Set the codec specific data to flac, but leave it empty since we don't
+      // have METADATA_BLOCK_STREAMINFO in the frame.
+      mInfo.mCodecSpecificConfig =
+          AudioCodecSpecificVariant{FlacCodecSpecificData{}};
+    }
+
+    return mValid;
+  }
+
+ private:
+  friend class Frame;
+  enum {
+    FLAC_CHMODE_INDEPENDENT = 0,
+    FLAC_CHMODE_LEFT_SIDE,
+    FLAC_CHMODE_RIGHT_SIDE,
+    FLAC_CHMODE_MID_SIDE,
+  };
+  AudioInfo mInfo;
+  // mFrameOrSampleNum is either:
+  // 1- coded sample number if blocksize is variable or
+  // 2- coded frame number if blocksize is fixed.
+  // A frame is made of Blocksize sample.
+  uint64_t mFrameOrSampleNum = 0;
+  // Index in samples from start;
+  int64_t mIndex = 0;
+  bool mVariableBlockSize = false;
+  uint32_t mBlocksize = 0;
+  uint32_t mSize = 0;
+  bool mValid = false;
+
+  static const uint32_t FlacSampleRateTable[16];
+  static const uint32_t FlacBlocksizeTable[16];
+  static const uint8_t FlacSampleSizeTable[8];
+  static const uint8_t CRC8Table[256];
+};
+
+const uint32_t FrameHeader::FlacSampleRateTable[16] = {
+    0,     88200, 176400, 192000, 8000, 16000, 22050, 24000,
+    32000, 44100, 48000,  96000,  0,    0,     0,     0};
+
+const uint32_t FrameHeader::FlacBlocksizeTable[16] = {
+    0,        192,      576 << 0, 576 << 1, 576 << 2, 576 << 3,
+    0,        0,        256 << 0, 256 << 1, 256 << 2, 256 << 3,
+    256 << 4, 256 << 5, 256 << 6, 256 << 7};
+
+const uint8_t FrameHeader::FlacSampleSizeTable[8] = {0,  8,  12, 0,
+                                                     16, 20, 24, 0};
+
+const uint8_t FrameHeader::CRC8Table[256] = {
+    0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15, 0x38, 0x3F, 0x36, 0x31,
+    0x24, 0x23, 0x2A, 0x2D, 0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
+    0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D, 0xE0, 0xE7, 0xEE, 0xE9,
+    0xFC, 0xFB, 0xF2, 0xF5, 0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
+    0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85, 0xA8, 0xAF, 0xA6, 0xA1,
+    0xB4, 0xB3, 0xBA, 0xBD, 0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
+    0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA, 0xB7, 0xB0, 0xB9, 0xBE,
+    0xAB, 0xAC, 0xA5, 0xA2, 0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
+    0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32, 0x1F, 0x18, 0x11, 0x16,
+    0x03, 0x04, 0x0D, 0x0A, 0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
+    0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A, 0x89, 0x8E, 0x87, 0x80,
+    0x95, 0x92, 0x9B, 0x9C, 0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
+    0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC, 0xC1, 0xC6, 0xCF, 0xC8,
+    0xDD, 0xDA, 0xD3, 0xD4, 0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
+    0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44, 0x19, 0x1E, 0x17, 0x10,
+    0x05, 0x02, 0x0B, 0x0C, 0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
+    0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B, 0x76, 0x71, 0x78, 0x7F,
+    0x6A, 0x6D, 0x64, 0x63, 0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
+    0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13, 0xAE, 0xA9, 0xA0, 0xA7,
+    0xB2, 0xB5, 0xBC, 0xBB, 0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
+    0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB, 0xE6, 0xE1, 0xE8, 0xEF,
+    0xFA, 0xFD, 0xF4, 0xF3};
+
+// flac::Frame - Frame meta container used to parse and hold a frame
+// header and side info.
+class Frame {
+ public:
+  // The FLAC signature is made of 14 bits set to 1; however the 15th bit is
+  // mandatorily set to 0, so we need to find either of 0xfffc or 0xfffd 2-bytes
+  // signature. We first use a bitmask to see if 0xfc or 0xfd is present. And if
+  // so we check for the whole signature.
+  int64_t FindNext(const uint8_t* aData, const uint32_t aLength) {
+    // The non-variable size of a FLAC header is 32 bits followed by variable
+    // size data and a 8 bits CRC.
+    // There's no need to read the last 4 bytes, it can never make a complete
+    // header.
+    if (aLength < 4) {
+      return -1;
+    }
+    uint32_t modOffset = aLength % 4;
+    uint32_t i, j;
+
+    for (i = 0; i < modOffset; i++) {
+      if ((BigEndian::readUint16(aData + i) & 0xfffe) == 0xfff8) {
+        if (mHeader.Parse(aData + i, aLength - i)) {
+          return i;
+        }
+      }
+    }
+
+    for (; i < aLength - 4; i += 4) {
+      uint32_t x = BigEndian::readUint32(aData + i);
+      if (((x & ~(x + 0x01010101)) & 0x80808080)) {
+        for (j = 0; j < 4; j++) {
+          if ((BigEndian::readUint16(aData + i + j) & 0xfffe) == 0xfff8) {
+            if (mHeader.Parse(aData + i + j, aLength - i - j)) {
+              return i + j;
+            }
+          }
+        }
+      }
+    }
+    return -1;
+  }
+
+  // Find the next frame start in the current resource.
+  // On exit return true, offset is set and resource points to the frame found.
+  bool FindNext(MediaResourceIndex& aResource) {
+    static const int BUFFER_SIZE = 4096;
+
+    Reset();
+
+    nsTArray<char> buffer;
+    uint64_t originalOffset = static_cast<uint64_t>(aResource.Tell());
+    uint64_t offset = originalOffset;
+    uint32_t innerOffset = 0;
+
+    do {
+      uint32_t read = 0;
+      buffer.SetLength(BUFFER_SIZE + innerOffset);
+      nsresult rv =
+          aResource.Read(buffer.Elements() + innerOffset, BUFFER_SIZE, &read);
+      if (NS_FAILED(rv)) {
+        return false;
+      }
+
+      const size_t bufSize = read + innerOffset;
+      int64_t foundOffset =
+          FindNext(reinterpret_cast<uint8_t*>(buffer.Elements()), bufSize);
+
+      if (foundOffset >= 0) {
+        SetOffset(aResource, static_cast<uint64_t>(foundOffset) + offset);
+        return true;
+      }
+
+      if (read < BUFFER_SIZE) {
+        // Nothing more to try on as we had reached EOS during the previous
+        // read.
+        mEOS = true;
+        return false;
+      }
+
+      // Scan the next block;
+      // We rewind a bit to re-try what could have been an incomplete packet.
+      // The maximum size of a FLAC header being FLAC_MAX_FRAME_HEADER_SIZE so
+      // we need to retry just after that amount.
+      offset += bufSize - (FLAC_MAX_FRAME_HEADER_SIZE + 1);
+      buffer.RemoveElementsAt(0, bufSize - (FLAC_MAX_FRAME_HEADER_SIZE + 1));
+      innerOffset = buffer.Length();
+    } while (offset - originalOffset < FLAC_MAX_FRAME_SIZE);
+
+    return false;
+  }
+
+  uint64_t Offset() const { return mOffset; }
+
+  const AudioInfo& Info() const { return Header().Info(); }
+
+  void SetEndOffset(uint64_t aOffset) { mSize = aOffset - mOffset; }
+
+  void SetEndTime(int64_t aIndex) {
+    if (aIndex > Header().mIndex) {
+      mDuration = aIndex - Header().mIndex;
+    }
+  }
+
+  void ResetStartTimeIfNeeded(const Frame& aReferenceFrame) {
+    if (Header().mVariableBlockSize ||
+        aReferenceFrame.Header().mVariableBlockSize ||
+        aReferenceFrame.Header().mBlocksize <= Header().mBlocksize) {
+      // Not a fixed size frame, or nothing to adjust.
+      return;
+    }
+    mHeader.mIndex =
+        Header().mFrameOrSampleNum * aReferenceFrame.Header().mBlocksize;
+  }
+
+  uint32_t Size() const { return mSize; }
+
+  TimeUnit Time() const {
+    if (!IsValid()) {
+      return TimeUnit::Invalid();
+    }
+    MOZ_ASSERT(Header().Info().mRate, "Invalid Frame. Need Header");
+    return FramesToTimeUnit(Header().mIndex, Header().Info().mRate);
+  }
+
+  TimeUnit Duration() const {
+    if (!IsValid()) {
+      return TimeUnit();
+    }
+    MOZ_ASSERT(Header().Info().mRate, "Invalid Frame. Need Header");
+    return FramesToTimeUnit(mDuration, Header().Info().mRate);
+  }
+
+  // Returns the parsed frame header.
+  const FrameHeader& Header() const { return mHeader; }
+
+  bool IsValid() const { return mHeader.IsValid(); }
+
+  bool EOS() const { return mEOS; }
+
+  void SetRate(uint32_t aRate) { mHeader.mInfo.mRate = aRate; };
+
+  void SetBitDepth(uint32_t aBitDepth) { mHeader.mInfo.mBitDepth = aBitDepth; }
+
+  void SetInvalid() { mHeader.mValid = false; }
+
+  // Resets the frame header and data.
+  void Reset() { *this = Frame(); }
+
+ private:
+  void SetOffset(MediaResourceIndex& aResource, uint64_t aOffset) {
+    mOffset = aOffset;
+    aResource.Seek(SEEK_SET, mOffset);
+  }
+
+  // The offset to the start of the header.
+  uint64_t mOffset = 0;
+  uint32_t mSize = 0;
+  uint32_t mDuration = 0;
+  bool mEOS = false;
+
+  // The currently parsed frame header.
+  FrameHeader mHeader;
+};
+
+class FrameParser {
+ public:
+  // Returns the currently parsed frame. Reset via EndFrameSession.
+  const Frame& CurrentFrame() const { return mFrame; }
+
+  // Returns the first parsed frame.
+  const Frame& FirstFrame() const { return mFirstFrame; }
+
+  // Clear the last parsed frame to allow for next frame parsing
+  void EndFrameSession() {
+    mNextFrame.Reset();
+    mFrame.Reset();
+  }
+
+  // Attempt to find the next frame.
+  bool FindNextFrame(MediaResourceIndex& aResource) {
+    mFrame = mNextFrame;
+    if (GetNextFrame(aResource)) {
+      if (!mFrame.IsValid()) {
+        mFrame = mNextFrame;
+        // We need two frames to be able to start playing (or have reached EOS).
+        GetNextFrame(aResource);
+      }
+    }
+
+    if (mFrame.IsValid()) {
+      if (mNextFrame.EOS()) {
+        mFrame.SetEndOffset(static_cast<uint64_t>(aResource.Tell()));
+        // If the blocksize is fixed, the frame's starting sample number will be
+        // the frame number times the blocksize. However, the last block may
+        // have been incorrectly set as shorter than the stream blocksize.
+        // We recalculate the start time of this last sample using the first
+        // frame blocksize.
+        // TODO: should we use an overall counter of frames instead?
+        mFrame.ResetStartTimeIfNeeded(mFirstFrame);
+      } else if (mNextFrame.IsValid()) {
+        mFrame.SetEndOffset(mNextFrame.Offset());
+        mFrame.SetEndTime(mNextFrame.Header().Index());
+      }
+    }
+
+    if (!mFirstFrame.IsValid()) {
+      mFirstFrame = mFrame;
+    }
+    return mFrame.IsValid();
+  }
+
+  // Convenience methods to external FlacFrameParser ones.
+  bool IsHeaderBlock(const uint8_t* aPacket, size_t aLength) const {
+    auto res = mParser.IsHeaderBlock(aPacket, aLength);
+    return res.isOk() ? res.unwrap() : false;
+  }
+
+  uint32_t HeaderBlockLength(const uint8_t* aPacket) const {
+    return mParser.HeaderBlockLength(aPacket);
+  }
+
+  bool DecodeHeaderBlock(const uint8_t* aPacket, size_t aLength) {
+    return mParser.DecodeHeaderBlock(aPacket, aLength).isOk();
+  }
+
+  bool HasFullMetadata() const { return mParser.HasFullMetadata(); }
+
+  AudioInfo Info() const { return mParser.mInfo; }
+
+  // Return a hash table with tag metadata.
+  UniquePtr<MetadataTags> GetTags() const { return mParser.GetTags(); }
+
+ private:
+  bool GetNextFrame(MediaResourceIndex& aResource) {
+    while (mNextFrame.FindNext(aResource)) {
+      // Move our offset slightly, so that we don't find the same frame at the
+      // next FindNext call.
+      aResource.Seek(SEEK_CUR, mNextFrame.Header().Size());
+      if (mFrame.IsValid() &&
+          mNextFrame.Offset() - mFrame.Offset() < FLAC_MAX_FRAME_SIZE &&
+          !CheckCRC16AtOffset(mFrame.Offset(), mNextFrame.Offset(),
+                              aResource)) {
+        // The frame doesn't match its CRC or would be too far, skip it..
+        continue;
+      }
+      CheckFrameData();
+      break;
+    }
+    return mNextFrame.IsValid();
+  }
+
+  bool CheckFrameData() {
+    if (mNextFrame.Header().Info().mRate == 0 ||
+        mNextFrame.Header().Info().mBitDepth == 0) {
+      if (!Info().IsValid()) {
+        // We can only use the STREAMINFO data if we have one.
+        mNextFrame.SetInvalid();
+      } else {
+        if (mNextFrame.Header().Info().mRate == 0) {
+          mNextFrame.SetRate(Info().mRate);
+        }
+        if (mNextFrame.Header().Info().mBitDepth == 0) {
+          mNextFrame.SetBitDepth(Info().mBitDepth);
+        }
+      }
+    }
+    return mNextFrame.IsValid();
+  }
+
+  bool CheckCRC16AtOffset(int64_t aStart, int64_t aEnd,
+                          MediaResourceIndex& aResource) const {
+    int64_t size = aEnd - aStart;
+    if (size <= 0) {
+      return false;
+    }
+    UniquePtr<char[]> buffer(new char[static_cast<size_t>(size)]);
+    uint32_t read = 0;
+    if (NS_FAILED(aResource.ReadAt(aStart, buffer.get(), size, &read)) ||
+        read != size) {
+      NS_WARNING("Couldn't read frame content");
+      return false;
+    }
+
+    uint16_t crc = 0;
+    uint8_t* buf = reinterpret_cast<uint8_t*>(buffer.get());
+    const uint8_t* end = buf + size;
+    while (buf < end) {
+      crc = CRC16Table[((uint8_t)crc) ^ *buf++] ^ (crc >> 8);
+    }
+#ifdef FUZZING
+    return true;
+#else
+    return !crc;
+#endif
+  }
+
+  const uint16_t CRC16Table[256] = {
+      0x0000, 0x0580, 0x0F80, 0x0A00, 0x1B80, 0x1E00, 0x1400, 0x1180, 0x3380,
+      0x3600, 0x3C00, 0x3980, 0x2800, 0x2D80, 0x2780, 0x2200, 0x6380, 0x6600,
+      0x6C00, 0x6980, 0x7800, 0x7D80, 0x7780, 0x7200, 0x5000, 0x5580, 0x5F80,
+      0x5A00, 0x4B80, 0x4E00, 0x4400, 0x4180, 0xC380, 0xC600, 0xCC00, 0xC980,
+      0xD800, 0xDD80, 0xD780, 0xD200, 0xF000, 0xF580, 0xFF80, 0xFA00, 0xEB80,
+      0xEE00, 0xE400, 0xE180, 0xA000, 0xA580, 0xAF80, 0xAA00, 0xBB80, 0xBE00,
+      0xB400, 0xB180, 0x9380, 0x9600, 0x9C00, 0x9980, 0x8800, 0x8D80, 0x8780,
+      0x8200, 0x8381, 0x8601, 0x8C01, 0x8981, 0x9801, 0x9D81, 0x9781, 0x9201,
+      0xB001, 0xB581, 0xBF81, 0xBA01, 0xAB81, 0xAE01, 0xA401, 0xA181, 0xE001,
+      0xE581, 0xEF81, 0xEA01, 0xFB81, 0xFE01, 0xF401, 0xF181, 0xD381, 0xD601,
+      0xDC01, 0xD981, 0xC801, 0xCD81, 0xC781, 0xC201, 0x4001, 0x4581, 0x4F81,
+      0x4A01, 0x5B81, 0x5E01, 0x5401, 0x5181, 0x7381, 0x7601, 0x7C01, 0x7981,
+      0x6801, 0x6D81, 0x6781, 0x6201, 0x2381, 0x2601, 0x2C01, 0x2981, 0x3801,
+      0x3D81, 0x3781, 0x3201, 0x1001, 0x1581, 0x1F81, 0x1A01, 0x0B81, 0x0E01,
+      0x0401, 0x0181, 0x0383, 0x0603, 0x0C03, 0x0983, 0x1803, 0x1D83, 0x1783,
+      0x1203, 0x3003, 0x3583, 0x3F83, 0x3A03, 0x2B83, 0x2E03, 0x2403, 0x2183,
+      0x6003, 0x6583, 0x6F83, 0x6A03, 0x7B83, 0x7E03, 0x7403, 0x7183, 0x5383,
+      0x5603, 0x5C03, 0x5983, 0x4803, 0x4D83, 0x4783, 0x4203, 0xC003, 0xC583,
+      0xCF83, 0xCA03, 0xDB83, 0xDE03, 0xD403, 0xD183, 0xF383, 0xF603, 0xFC03,
+      0xF983, 0xE803, 0xED83, 0xE783, 0xE203, 0xA383, 0xA603, 0xAC03, 0xA983,
+      0xB803, 0xBD83, 0xB783, 0xB203, 0x9003, 0x9583, 0x9F83, 0x9A03, 0x8B83,
+      0x8E03, 0x8403, 0x8183, 0x8002, 0x8582, 0x8F82, 0x8A02, 0x9B82, 0x9E02,
+      0x9402, 0x9182, 0xB382, 0xB602, 0xBC02, 0xB982, 0xA802, 0xAD82, 0xA782,
+      0xA202, 0xE382, 0xE602, 0xEC02, 0xE982, 0xF802, 0xFD82, 0xF782, 0xF202,
+      0xD002, 0xD582, 0xDF82, 0xDA02, 0xCB82, 0xCE02, 0xC402, 0xC182, 0x4382,
+      0x4602, 0x4C02, 0x4982, 0x5802, 0x5D82, 0x5782, 0x5202, 0x7002, 0x7582,
+      0x7F82, 0x7A02, 0x6B82, 0x6E02, 0x6402, 0x6182, 0x2002, 0x2582, 0x2F82,
+      0x2A02, 0x3B82, 0x3E02, 0x3402, 0x3182, 0x1382, 0x1602, 0x1C02, 0x1982,
+      0x0802, 0x0D82, 0x0782, 0x0202,
+  };
+
+  FlacFrameParser mParser;
+  // We keep the first parsed frame around for static info access
+  // and the currently parsed frame.
+  Frame mFirstFrame;
+  Frame mNextFrame;
+  Frame mFrame;
+};
+
+}  // namespace flac
+
+// FlacDemuxer
+
+FlacDemuxer::FlacDemuxer(MediaResource* aSource) : mSource(aSource) {
+  DDLINKCHILD("source", aSource);
+}
+
+bool FlacDemuxer::InitInternal() {
+  if (!mTrackDemuxer) {
+    mTrackDemuxer = new FlacTrackDemuxer(mSource);
+    DDLINKCHILD("track demuxer", mTrackDemuxer.get());
+  }
+  return mTrackDemuxer->Init();
+}
+
+RefPtr<FlacDemuxer::InitPromise> FlacDemuxer::Init() {
+  if (!InitInternal()) {
+    LOG("Init() failure: waiting for data");
+
+    return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
+                                        __func__);
+  }
+
+  LOG("Init() successful");
+  return InitPromise::CreateAndResolve(NS_OK, __func__);
+}
+
+uint32_t FlacDemuxer::GetNumberTracks(TrackInfo::TrackType aType) const {
+  return (aType == TrackInfo::kAudioTrack) ? 1 : 0;
+}
+
+already_AddRefed<MediaTrackDemuxer> FlacDemuxer::GetTrackDemuxer(
+    TrackInfo::TrackType aType, uint32_t aTrackNumber) {
+  if (!mTrackDemuxer) {
+    return nullptr;
+  }
+
+  return RefPtr<FlacTrackDemuxer>(mTrackDemuxer).forget();
+}
+
+bool FlacDemuxer::IsSeekable() const {
+  return mTrackDemuxer && mTrackDemuxer->IsSeekable();
+}
+
+// FlacTrackDemuxer
+FlacTrackDemuxer::FlacTrackDemuxer(MediaResource* aSource)
+    : mSource(aSource), mParser(new flac::FrameParser()), mTotalFrameLen(0) {
+  DDLINKCHILD("source", aSource);
+  Reset();
+}
+
+FlacTrackDemuxer::~FlacTrackDemuxer() = default;
+
+bool FlacTrackDemuxer::Init() {
+  static const int BUFFER_SIZE = 4096;
+
+  // First check if we have a valid Flac start.
+  char buffer[BUFFER_SIZE];
+  const uint8_t* ubuffer =  // only needed due to type constraints of ReadAt.
+      reinterpret_cast<uint8_t*>(buffer);
+  int64_t offset = 0;
+
+  do {
+    uint32_t read = 0;
+    nsresult ret = mSource.ReadAt(offset, buffer, BUFFER_SIZE, &read);
+    if (NS_FAILED(ret) || read < BUFFER_SIZE) {
+      // Assume that if we can't read that many bytes while parsing the header,
+      // that something is wrong.
+      return false;
+    }
+    if (!mParser->IsHeaderBlock(ubuffer, BUFFER_SIZE)) {
+      // Not a header and we haven't reached the end of the metadata blocks.
+      // Will fall back to using the frames header instead.
+      break;
+    }
+    uint32_t sizeHeader = mParser->HeaderBlockLength(ubuffer);
+    RefPtr<MediaByteBuffer> block = mSource.MediaReadAt(offset, sizeHeader);
+    if (!block || block->Length() != sizeHeader) {
+      break;
+    }
+    if (!mParser->DecodeHeaderBlock(block->Elements(), sizeHeader)) {
+      break;
+    }
+    offset += sizeHeader;
+  } while (!mParser->HasFullMetadata());
+
+  // First flac frame is found after the metadata.
+  // Can seek there immediately to avoid reparsing it all.
+  mSource.Seek(SEEK_SET, offset);
+
+  // Find the first frame to fully initialise our parser.
+  if (mParser->FindNextFrame(mSource)) {
+    // Ensure that the next frame returned will be the first.
+    mSource.Seek(SEEK_SET, mParser->FirstFrame().Offset());
+    mParser->EndFrameSession();
+  } else if (!mParser->Info().IsValid() || !mParser->FirstFrame().IsValid()) {
+    // We must find at least a frame to determine the metadata.
+    // We can't play this stream.
+    return false;
+  }
+
+  if (!mParser->Info().IsValid() || !mParser->Info().mDuration.IsPositive()) {
+    // Check if we can look at the last frame for the end time to determine the
+    // duration when we don't have any.
+    TimeAtEnd();
+  }
+
+  return true;
+}
+
+UniquePtr<TrackInfo> FlacTrackDemuxer::GetInfo() const {
+  if (mParser->Info().IsValid()) {
+    // We have a proper metadata header.
+    UniquePtr<TrackInfo> info = mParser->Info().Clone();
+    UniquePtr<MetadataTags> tags(mParser->GetTags());
+    if (tags) {
+      for (const auto& entry : *tags) {
+        info->mTags.AppendElement(MetadataTag(entry.GetKey(), entry.GetData()));
+      }
+    }
+    MOZ_ASSERT(info->IsAudio() &&
+                   info->GetAsAudioInfo()
+                       ->mCodecSpecificConfig.is<FlacCodecSpecificData>(),
+               "Should get flac specific data from parser");
+    return info;
+  } else if (mParser->FirstFrame().Info().IsValid()) {
+    // Use the first frame header.
+    UniquePtr<TrackInfo> info = mParser->FirstFrame().Info().Clone();
+    info->mDuration = Duration();
+    MOZ_ASSERT(info->IsAudio() &&
+                   info->GetAsAudioInfo()
+                       ->mCodecSpecificConfig.is<FlacCodecSpecificData>(),
+               "Should get flac specific data from parser");
+    return info;
+  }
+  return nullptr;
+}
+
+bool FlacTrackDemuxer::IsSeekable() const {
+  // For now we only allow seeking if a STREAMINFO block was found and with
+  // a known number of samples (duration is set).
+  return mParser->Info().IsValid() && mParser->Info().mDuration.IsPositive();
+}
+
+RefPtr<FlacTrackDemuxer::SeekPromise> FlacTrackDemuxer::Seek(
+    const TimeUnit& aTime) {
+  // 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 FlacTrackDemuxer::FastSeek(const TimeUnit& aTime) {
+  LOG("FastSeek(%f) avgFrameLen=%f mParsedFramesDuration=%f offset=%" PRId64,
+      aTime.ToSeconds(), AverageFrameLength(),
+      mParsedFramesDuration.ToSeconds(), GetResourceOffset());
+
+  // Invalidate current frames in the parser.
+  mParser->EndFrameSession();
+
+  if (!mParser->FirstFrame().IsValid()) {
+    // Something wrong, and there's nothing to seek to anyway, so we can
+    // do whatever here.
+    mSource.Seek(SEEK_SET, 0);
+    return TimeUnit();
+  }
+
+  if (aTime <= mParser->FirstFrame().Time()) {
+    // We're attempting to seek prior the first frame, return the first frame.
+    mSource.Seek(SEEK_SET, mParser->FirstFrame().Offset());
+    return mParser->FirstFrame().Time();
+  }
+
+  // We look for the seek position using a bisection search, starting where the
+  // estimated position might be using the average frame length.
+  // Typically, with flac such approximation is typically useless.
+
+  // Estimate where the position might be.
+  int64_t pivot =
+      aTime.ToSeconds() * AverageFrameLength() + mParser->FirstFrame().Offset();
+
+  // Time in seconds where we can stop seeking and will continue using
+  // ScanUntil.
+  static const int GAP_THRESHOLD = 5;
+  int64_t first = mParser->FirstFrame().Offset();
+  int64_t last = mSource.GetLength();
+  Maybe<uint64_t> lastFoundOffset;
+  uint32_t iterations = 0;
+  TimeUnit timeSeekedTo;
+
+  do {
+    iterations++;
+    mSource.Seek(SEEK_SET, pivot);
+    flac::Frame frame;
+    if (!frame.FindNext(mSource)) {
+      NS_WARNING("We should have found a point");
+      break;
+    }
+    timeSeekedTo = frame.Time();
+
+    LOGV("FastSeek: interation:%u found:%f @ %" PRIu64, iterations,
+         timeSeekedTo.ToSeconds(), frame.Offset());
+
+    if (lastFoundOffset && lastFoundOffset.ref() == frame.Offset()) {
+      // Same frame found twice. We're done.
+      break;
+    }
+    lastFoundOffset = Some(frame.Offset());
+
+    if (frame.Time() == aTime) {
+      break;
+    }
+    if (aTime > frame.Time() &&
+        aTime - frame.Time() <= TimeUnit::FromSeconds(GAP_THRESHOLD)) {
+      // We're close enough to the target, experimentation shows that bisection
+      // search doesn't help much after that.
+      break;
+    }
+    if (frame.Time() > aTime) {
+      last = pivot;
+      pivot -= (pivot - first) / 2;
+    } else {
+      first = pivot;
+      pivot += (last - pivot) / 2;
+    }
+  } while (true);
+
+  if (lastFoundOffset) {
+    mSource.Seek(SEEK_SET, lastFoundOffset.ref());
+  }
+
+  return timeSeekedTo;
+}
+
+TimeUnit FlacTrackDemuxer::ScanUntil(const TimeUnit& aTime) {
+  LOG("ScanUntil(%f avgFrameLen=%f mParsedFramesDuration=%f offset=%" PRId64,
+      aTime.ToSeconds(), AverageFrameLength(),
+      mParsedFramesDuration.ToSeconds(), mParser->CurrentFrame().Offset());
+
+  if (!mParser->FirstFrame().IsValid() ||
+      aTime <= mParser->FirstFrame().Time()) {
+    return FastSeek(aTime);
+  }
+
+  int64_t previousOffset = 0;
+  TimeUnit previousTime;
+  while (FindNextFrame().IsValid() && mParser->CurrentFrame().Time() < aTime) {
+    previousOffset = mParser->CurrentFrame().Offset();
+    previousTime = mParser->CurrentFrame().Time();
+  }
+
+  if (!mParser->CurrentFrame().IsValid()) {
+    // We reached EOS.
+    return Duration();
+  }
+
+  // Seek back to the last frame found prior the target.
+  mParser->EndFrameSession();
+  mSource.Seek(SEEK_SET, previousOffset);
+  return previousTime;
+}
+
+RefPtr<FlacTrackDemuxer::SamplesPromise> FlacTrackDemuxer::GetSamples(
+    int32_t aNumSamples) {
+  LOGV("GetSamples(%d) Begin offset=%" PRId64
+       " mParsedFramesDuration=%f"
+       " mTotalFrameLen=%" PRIu64,
+       aNumSamples, GetResourceOffset(), mParsedFramesDuration.ToSeconds(),
+       mTotalFrameLen);
+
+  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);
+  }
+
+  LOGV("GetSamples() End mSamples.Length=%zu aNumSamples=%d offset=%" PRId64
+       " mParsedFramesDuration=%f mTotalFrameLen=%" PRIu64,
+       frames->GetSamples().Length(), aNumSamples, GetResourceOffset(),
+       mParsedFramesDuration.ToSeconds(), mTotalFrameLen);
+
+  if (frames->GetSamples().IsEmpty()) {
+    return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_END_OF_STREAM,
+                                           __func__);
+  }
+
+  return SamplesPromise::CreateAndResolve(frames, __func__);
+}
+
+void FlacTrackDemuxer::Reset() {
+  LOG("Reset()");
+  MOZ_ASSERT(mParser);
+  if (mParser->FirstFrame().IsValid()) {
+    mSource.Seek(SEEK_SET, mParser->FirstFrame().Offset());
+  } else {
+    mSource.Seek(SEEK_SET, 0);
+  }
+  mParser->EndFrameSession();
+}
+
+RefPtr<FlacTrackDemuxer::SkipAccessPointPromise>
+FlacTrackDemuxer::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 FlacTrackDemuxer::GetResourceOffset() const { return mSource.Tell(); }
+
+TimeIntervals FlacTrackDemuxer::GetBuffered() {
+  TimeUnit duration = Duration();
+
+  if (duration <= TimeUnit()) {
+    return TimeIntervals();
+  }
+
+  // We could simply parse the cached data instead and read the timestamps.
+  // However, for now this will do.
+  AutoPinned<MediaResource> stream(mSource.GetResource());
+  return GetEstimatedBufferedTimeRanges(stream, duration.ToMicroseconds());
+}
+
+const flac::Frame& FlacTrackDemuxer::FindNextFrame() {
+  LOGV("FindNext() Begin offset=%" PRId64
+       " mParsedFramesDuration=%f"
+       " mTotalFrameLen=%" PRIu64,
+       GetResourceOffset(), mParsedFramesDuration.ToSeconds(), mTotalFrameLen);
+
+  if (mParser->FindNextFrame(mSource)) {
+    // Update our current progress stats.
+    mParsedFramesDuration =
+        std::max(mParsedFramesDuration, mParser->CurrentFrame().Time() -
+                                            mParser->FirstFrame().Time() +
+                                            mParser->CurrentFrame().Duration());
+    mTotalFrameLen =
+        std::max<uint64_t>(mTotalFrameLen, mParser->CurrentFrame().Offset() -
+                                               mParser->FirstFrame().Offset() +
+                                               mParser->CurrentFrame().Size());
+
+    LOGV("FindNext() End time=%f offset=%" PRId64
+         " mParsedFramesDuration=%f"
+         " mTotalFrameLen=%" PRIu64,
+         mParser->CurrentFrame().Time().ToSeconds(), GetResourceOffset(),
+         mParsedFramesDuration.ToSeconds(), mTotalFrameLen);
+  }
+
+  return mParser->CurrentFrame();
+}
+
+already_AddRefed<MediaRawData> FlacTrackDemuxer::GetNextFrame(
+    const flac::Frame& aFrame) {
+  if (!aFrame.IsValid()) {
+    LOG("GetNextFrame() EOS");
+    return nullptr;
+  }
+
+  LOG("GetNextFrame() Begin(time=%f offset=%" PRId64 " size=%u)",
+      aFrame.Time().ToSeconds(), aFrame.Offset(), aFrame.Size());
+
+  const uint64_t offset = aFrame.Offset();
+  const uint32_t size = aFrame.Size();
+
+  RefPtr<MediaRawData> frame = new MediaRawData();
+  frame->mOffset = offset;
+
+  UniquePtr<MediaRawDataWriter> frameWriter(frame->CreateWriter());
+  if (!frameWriter->SetSize(size)) {
+    LOG("GetNext() Exit failed to allocated media buffer");
+    return nullptr;
+  }
+
+  const uint32_t read = Read(frameWriter->Data(), offset, size);
+  if (read != size) {
+    LOG("GetNextFrame() Exit read=%u frame->Size=%zu", read, frame->Size());
+    return nullptr;
+  }
+
+  frame->mTime = aFrame.Time();
+  frame->mDuration = aFrame.Duration();
+  frame->mTimecode = frame->mTime;
+  frame->mOffset = aFrame.Offset();
+  frame->mKeyframe = true;
+
+  MOZ_ASSERT(!frame->mTime.IsNegative());
+  MOZ_ASSERT(!frame->mDuration.IsNegative());
+
+  return frame.forget();
+}
+
+uint32_t FlacTrackDemuxer::Read(uint8_t* aBuffer, int64_t aOffset,
+                                int32_t aSize) {
+  uint32_t read = 0;
+  const nsresult rv = mSource.ReadAt(aOffset, reinterpret_cast<char*>(aBuffer),
+                                     static_cast<uint32_t>(aSize), &read);
+  NS_ENSURE_SUCCESS(rv, 0);
+  return read;
+}
+
+double FlacTrackDemuxer::AverageFrameLength() const {
+  if (mParsedFramesDuration.ToMicroseconds()) {
+    return mTotalFrameLen / mParsedFramesDuration.ToSeconds();
+  }
+
+  return 0.0;
+}
+
+TimeUnit FlacTrackDemuxer::Duration() const {
+  return std::max(mParsedFramesDuration, mParser->Info().mDuration);
+}
+
+TimeUnit FlacTrackDemuxer::TimeAtEnd() {
+  // Scan the last 128kB if available to determine the last frame.
+  static const int OFFSET_FROM_END = 128 * 1024;
+
+  // Seek to the end of the file and attempt to find the last frame.
+  MediaResourceIndex source(mSource.GetResource());
+  TimeUnit previousDuration;
+  TimeUnit previousTime;
+
+  const int64_t streamLen = mSource.GetLength();
+  if (streamLen < 0) {
+    return TimeUnit::FromInfinity();
+  }
+
+  flac::FrameParser parser;
+
+  source.Seek(SEEK_SET, std::max<int64_t>(0LL, streamLen - OFFSET_FROM_END));
+  while (parser.FindNextFrame(source)) {
+    // FFmpeg flac muxer can generate a last frame with earlier than the others.
+    previousTime = std::max(previousTime, parser.CurrentFrame().Time());
+    if (parser.CurrentFrame().Duration() > TimeUnit()) {
+      // The last frame doesn't have a duration, so only update our duration
+      // if we do have one.
+      previousDuration = parser.CurrentFrame().Duration();
+    }
+    if (source.Tell() >= streamLen) {
+      // Limit the read, in case the length change half-way.
+      break;
+    }
+  }
+
+  // Update our current progress stats.
+  mParsedFramesDuration =
+      previousTime + previousDuration - mParser->FirstFrame().Time();
+
+  mTotalFrameLen =
+      static_cast<uint64_t>(streamLen) - mParser->FirstFrame().Offset();
+
+  return mParsedFramesDuration;
+}
+
+/* static */
+bool FlacDemuxer::FlacSniffer(const uint8_t* aData, const uint32_t aLength) {
+  if (aLength < FLAC_MIN_FRAME_SIZE) {
+    return false;
+  }
+
+  flac::Frame frame;
+  return frame.FindNext(aData, aLength) >= 0;
+}
+
+}  // namespace mozilla
diff --git a/dom/media/flac/FlacDemuxer.h b/dom/media/flac/FlacDemuxer.h
new file mode 100644
index 0000000000..cfbbfb7c57
--- /dev/null
+++ b/dom/media/flac/FlacDemuxer.h
@@ -0,0 +1,112 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef FLAC_DEMUXER_H_
+#define FLAC_DEMUXER_H_
+
+#include "mozilla/Attributes.h"
+#include "MediaDataDemuxer.h"
+#include "MediaResource.h"
+namespace mozilla {
+
+namespace flac {
+class Frame;
+class FrameParser;
+}  // namespace flac
+class FlacTrackDemuxer;
+
+DDLoggedTypeDeclNameAndBase(FlacDemuxer, MediaDataDemuxer);
+DDLoggedTypeNameAndBase(FlacTrackDemuxer, MediaTrackDemuxer);
+
+class FlacDemuxer : public MediaDataDemuxer,
+                    public DecoderDoctorLifeLogger<FlacDemuxer> {
+ public:
+  // MediaDataDemuxer interface.
+  explicit FlacDemuxer(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;
+
+  // Return true if a valid flac frame header could be found.
+  static bool FlacSniffer(const uint8_t* aData, const uint32_t aLength);
+
+ private:
+  bool InitInternal();
+
+  RefPtr<MediaResource> mSource;
+  RefPtr<FlacTrackDemuxer> mTrackDemuxer;
+};
+
+class FlacTrackDemuxer : public MediaTrackDemuxer,
+                         public DecoderDoctorLifeLogger<FlacTrackDemuxer> {
+ public:
+  explicit FlacTrackDemuxer(MediaResource* aSource);
+
+  // Initializes the track demuxer by reading the first frame for meta data.
+  // Returns initialization success state.
+  bool Init();
+
+  // 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;
+  int64_t GetResourceOffset() const override;
+  media::TimeIntervals GetBuffered() override;
+  RefPtr<SkipAccessPointPromise> SkipToNextRandomAccessPoint(
+      const media::TimeUnit& aTimeThreshold) override;
+
+  bool IsSeekable() const;
+
+ private:
+  // Destructor.
+  ~FlacTrackDemuxer();
+
+  // Returns the estimated stream duration, or a 0-duration if unknown.
+  media::TimeUnit Duration() const;
+  media::TimeUnit TimeAtEnd();
+
+  // 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 next valid frame and return it.
+  const flac::Frame& FindNextFrame();
+
+  // Returns the next ADTS frame, if available.
+  already_AddRefed<MediaRawData> GetNextFrame(const flac::Frame& aFrame);
+
+  // 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, int32_t aSize);
+
+  // Returns the average frame length derived from the previously parsed frames.
+  double AverageFrameLength() const;
+
+  // The (hopefully) Flac resource.
+  MediaResourceIndex mSource;
+
+  // Flac frame parser used to detect frames and extract side info.
+  UniquePtr<flac::FrameParser> mParser;
+
+  // Total duration of parsed frames.
+  media::TimeUnit mParsedFramesDuration;
+
+  // Sum of parsed frames' lengths in bytes.
+  uint64_t mTotalFrameLen;
+
+  // Audio track config info.
+  UniquePtr<AudioInfo> mInfo;
+};
+
+}  // namespace mozilla
+
+#endif  // !FLAC_DEMUXER_H_
diff --git a/dom/media/flac/FlacFrameParser.cpp b/dom/media/flac/FlacFrameParser.cpp
new file mode 100644
index 0000000000..528ba7c693
--- /dev/null
+++ b/dom/media/flac/FlacFrameParser.cpp
@@ -0,0 +1,244 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FlacFrameParser.h"
+#include "nsTArray.h"
+#include "OggCodecState.h"
+#include "OpusParser.h"
+#include "VideoUtils.h"
+#include "BufferReader.h"
+#include "mozilla/ResultExtensions.h"
+
+namespace mozilla {
+
+#define OGG_FLAC_METADATA_TYPE_STREAMINFO 0x7F
+#define FLAC_STREAMINFO_SIZE 34
+
+#define BITMASK(x) ((1ULL << x) - 1)
+
+enum {
+  FLAC_METADATA_TYPE_STREAMINFO = 0,
+  FLAC_METADATA_TYPE_PADDING,
+  FLAC_METADATA_TYPE_APPLICATION,
+  FLAC_METADATA_TYPE_SEEKTABLE,
+  FLAC_METADATA_TYPE_VORBIS_COMMENT,
+  FLAC_METADATA_TYPE_CUESHEET,
+  FLAC_METADATA_TYPE_PICTURE,
+  FLAC_METADATA_TYPE_INVALID = 127
+};
+
+FlacFrameParser::FlacFrameParser()
+    : mMinBlockSize(0),
+      mMaxBlockSize(0),
+      mMinFrameSize(0),
+      mMaxFrameSize(0),
+      mNumFrames(0),
+      mFullMetadata(false),
+      mPacketCount(0){};
+
+FlacFrameParser::~FlacFrameParser() = default;
+
+uint32_t FlacFrameParser::HeaderBlockLength(const uint8_t* aPacket) const {
+  uint32_t extra = 4;
+  if (aPacket[0] == 'f') {
+    // This must be the first block read, which contains the fLaC signature.
+    aPacket += 4;
+    extra += 4;
+  }
+  return (BigEndian::readUint32(aPacket) & BITMASK(24)) + extra;
+}
+
+Result<Ok, nsresult> FlacFrameParser::DecodeHeaderBlock(const uint8_t* aPacket,
+                                                        size_t aLength) {
+  if (aLength < 4 || aPacket[0] == 0xff) {
+    // Not a header block.
+    return Err(NS_ERROR_FAILURE);
+  }
+  BufferReader br(aPacket, aLength);
+
+  mPacketCount++;
+
+  if (aPacket[0] == 'f') {
+    if (mPacketCount != 1 || memcmp(br.Read(4), "fLaC", 4) ||
+        br.Remaining() != FLAC_STREAMINFO_SIZE + 4) {
+      return Err(NS_ERROR_FAILURE);
+    }
+  }
+  uint8_t blockHeader;
+  MOZ_TRY_VAR(blockHeader, br.ReadU8());
+  // blockType is a misnomer as it could indicate here either a packet type
+  // should it points to the start of a Flac in Ogg metadata, or an actual
+  // block type as per the flac specification.
+  uint32_t blockType = blockHeader & 0x7f;
+  bool lastBlock = blockHeader & 0x80;
+
+  if (blockType == OGG_FLAC_METADATA_TYPE_STREAMINFO) {
+    if (mPacketCount != 1 || memcmp(br.Read(4), "FLAC", 4) ||
+        br.Remaining() != FLAC_STREAMINFO_SIZE + 12) {
+      return Err(NS_ERROR_FAILURE);
+    }
+    uint32_t major;
+    MOZ_TRY_VAR(major, br.ReadU8());
+    if (major != 1) {
+      // unsupported version;
+      return Err(NS_ERROR_FAILURE);
+    }
+    MOZ_TRY(br.ReadU8());  // minor version
+    uint32_t header;
+    MOZ_TRY_VAR(header, br.ReadU16());
+    mNumHeaders = Some(header);
+    br.Read(4);  // fLaC
+    MOZ_TRY_VAR(blockType, br.ReadU8());
+    blockType &= BITMASK(7);
+    // First METADATA_BLOCK_STREAMINFO
+    if (blockType != FLAC_METADATA_TYPE_STREAMINFO) {
+      // First block must be a stream info.
+      return Err(NS_ERROR_FAILURE);
+    }
+  }
+
+  uint32_t blockDataSize;
+  MOZ_TRY_VAR(blockDataSize, br.ReadU24());
+  const uint8_t* blockDataStart = br.Peek(blockDataSize);
+  if (!blockDataStart) {
+    // Incomplete block.
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  switch (blockType) {
+    case FLAC_METADATA_TYPE_STREAMINFO: {
+      if (mPacketCount != 1 || blockDataSize != FLAC_STREAMINFO_SIZE) {
+        // STREAMINFO must be the first metadata block found, and its size
+        // is constant.
+        return Err(NS_ERROR_FAILURE);
+      }
+
+      MOZ_TRY_VAR(mMinBlockSize, br.ReadU16());
+      MOZ_TRY_VAR(mMaxBlockSize, br.ReadU16());
+      MOZ_TRY_VAR(mMinFrameSize, br.ReadU24());
+      MOZ_TRY_VAR(mMaxFrameSize, br.ReadU24());
+
+      uint64_t blob;
+      MOZ_TRY_VAR(blob, br.ReadU64());
+      uint32_t sampleRate = (blob >> 44) & BITMASK(20);
+      if (!sampleRate) {
+        return Err(NS_ERROR_FAILURE);
+      }
+      uint32_t numChannels = ((blob >> 41) & BITMASK(3)) + 1;
+      if (numChannels > FLAC_MAX_CHANNELS) {
+        return Err(NS_ERROR_FAILURE);
+      }
+      uint32_t bps = ((blob >> 36) & BITMASK(5)) + 1;
+      if (bps > 24) {
+        return Err(NS_ERROR_FAILURE);
+      }
+      mNumFrames = blob & BITMASK(36);
+
+      mInfo.mMimeType = "audio/flac";
+      mInfo.mRate = sampleRate;
+      mInfo.mChannels = numChannels;
+      mInfo.mBitDepth = bps;
+      FlacCodecSpecificData flacCodecSpecificData;
+      flacCodecSpecificData.mStreamInfoBinaryBlob->AppendElements(
+          blockDataStart, blockDataSize);
+      mInfo.mCodecSpecificConfig =
+          AudioCodecSpecificVariant{std::move(flacCodecSpecificData)};
+      auto duration = FramesToTimeUnit(mNumFrames, sampleRate);
+      mInfo.mDuration = duration.IsValid() ? duration : media::TimeUnit::Zero();
+      mParser = MakeUnique<OpusParser>();
+      break;
+    }
+    case FLAC_METADATA_TYPE_VORBIS_COMMENT: {
+      if (!mParser) {
+        // We must have seen a valid streaminfo first.
+        return Err(NS_ERROR_FAILURE);
+      }
+      nsTArray<uint8_t> comments(blockDataSize + 8);
+      comments.AppendElements("OpusTags", 8);
+      comments.AppendElements(blockDataStart, blockDataSize);
+      if (!mParser->DecodeTags(comments.Elements(), comments.Length())) {
+        return Err(NS_ERROR_FAILURE);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  if (mNumHeaders && mPacketCount > mNumHeaders.ref() + 1) {
+    // Received too many header block. assuming invalid.
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  if (lastBlock || (mNumHeaders && mNumHeaders.ref() + 1 == mPacketCount)) {
+    mFullMetadata = true;
+  }
+
+  return Ok();
+}
+
+int64_t FlacFrameParser::BlockDuration(const uint8_t* aPacket,
+                                       size_t aLength) const {
+  if (!mInfo.IsValid()) {
+    return -1;
+  }
+  if (mMinBlockSize == mMaxBlockSize) {
+    // block size is fixed, use this instead of looking at the frame header.
+    return mMinBlockSize;
+  }
+  // TODO
+  return 0;
+}
+
+Result<bool, nsresult> FlacFrameParser::IsHeaderBlock(const uint8_t* aPacket,
+                                                      size_t aLength) const {
+  // Ogg Flac header
+  // The one-byte packet type 0x7F
+  // The four-byte ASCII signature "FLAC", i.e. 0x46, 0x4C, 0x41, 0x43
+
+  // Flac header:
+  // "fLaC", the FLAC stream marker in ASCII, meaning byte 0 of the stream is
+  // 0x66, followed by 0x4C 0x61 0x43
+
+  // If we detect either a ogg or plain flac header, then it must be valid.
+  if (aLength < 4 || aPacket[0] == 0xff) {
+    // A header is at least 4 bytes.
+    return false;
+  }
+  if (aPacket[0] == 0x7f) {
+    // Ogg packet
+    BufferReader br(aPacket + 1, aLength - 1);
+    const uint8_t* signature = br.Read(4);
+    return signature && !memcmp(signature, "FLAC", 4);
+  }
+  BufferReader br(aPacket, aLength - 1);
+  const uint8_t* signature = br.Read(4);
+  if (signature && !memcmp(signature, "fLaC", 4)) {
+    // Flac start header, must have STREAMINFO as first metadata block;
+    uint32_t blockType;
+    MOZ_TRY_VAR(blockType, br.ReadU8());
+    blockType &= 0x7f;
+    return blockType == FLAC_METADATA_TYPE_STREAMINFO;
+  }
+  char type = aPacket[0] & 0x7f;
+  return type >= 1 && type <= 6;
+}
+
+UniquePtr<MetadataTags> FlacFrameParser::GetTags() const {
+  if (!mParser) {
+    return nullptr;
+  }
+
+  auto tags = MakeUnique<MetadataTags>();
+  for (uint32_t i = 0; i < mParser->mTags.Length(); i++) {
+    OggCodecState::AddVorbisComment(tags, mParser->mTags[i].Data(),
+                                    mParser->mTags[i].Length());
+  }
+
+  return tags;
+}
+
+}  // namespace mozilla
diff --git a/dom/media/flac/FlacFrameParser.h b/dom/media/flac/FlacFrameParser.h
new file mode 100644
index 0000000000..2bd457ea03
--- /dev/null
+++ b/dom/media/flac/FlacFrameParser.h
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef FLAC_FRAME_PARSER_H_
+#define FLAC_FRAME_PARSER_H_
+
+#include "mozilla/Maybe.h"
+#include "mozilla/Result.h"
+#include "MediaDecoder.h"  // For MetadataTags
+#include "MediaInfo.h"
+#include "MediaResource.h"
+
+namespace mozilla {
+
+#define FLAC_MAX_CHANNELS 8
+#define FLAC_MIN_BLOCKSIZE 16
+#define FLAC_MAX_BLOCKSIZE 65535
+#define FLAC_MIN_FRAME_SIZE 11
+#define FLAC_MAX_FRAME_HEADER_SIZE 16
+#define FLAC_MAX_FRAME_SIZE \
+  (FLAC_MAX_FRAME_HEADER_SIZE + FLAC_MAX_BLOCKSIZE * FLAC_MAX_CHANNELS * 3)
+
+class OpusParser;
+
+// Decode a Flac Metadata block contained in either a ogg packet
+// (https://xiph.org/flac/ogg_mapping.html) or in flac container
+// (https://xiph.org/flac/format.html#frame_header)
+
+class FlacFrameParser {
+ public:
+  FlacFrameParser();
+  ~FlacFrameParser();
+
+  Result<bool, nsresult> IsHeaderBlock(const uint8_t* aPacket,
+                                       size_t aLength) const;
+  // Return the length of the block header (METADATA_BLOCK_HEADER+
+  // METADATA_BLOCK_DATA), aPacket must point to at least 4
+  // bytes and to a valid block header start (as determined by IsHeaderBlock).
+  uint32_t HeaderBlockLength(const uint8_t* aPacket) const;
+  Result<Ok, nsresult> DecodeHeaderBlock(const uint8_t* aPacket,
+                                         size_t aLength);
+  bool HasFullMetadata() const { return mFullMetadata; }
+  // Return the duration in frames found in the block. -1 if error
+  // such as invalid packet.
+  int64_t BlockDuration(const uint8_t* aPacket, size_t aLength) const;
+
+  // Return a hash table with tag metadata.
+  UniquePtr<MetadataTags> GetTags() const;
+
+  AudioInfo mInfo;
+
+ private:
+  bool ReconstructFlacGranulepos(void);
+  Maybe<uint32_t> mNumHeaders;
+  uint32_t mMinBlockSize;
+  uint32_t mMaxBlockSize;
+  uint32_t mMinFrameSize;
+  uint32_t mMaxFrameSize;
+  uint64_t mNumFrames;
+  bool mFullMetadata;
+  uint32_t mPacketCount;
+
+  // Used to decode the vorbis comment metadata.
+  UniquePtr<OpusParser> mParser;
+};
+
+}  // namespace mozilla
+
+#endif  // FLAC_FRAME_PARSER_H_
diff --git a/dom/media/flac/moz.build b/dom/media/flac/moz.build
new file mode 100644
index 0000000000..0e3c8eae61
--- /dev/null
+++ b/dom/media/flac/moz.build
@@ -0,0 +1,24 @@
+# -*- Mode: python; 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 += [
+    "FlacDecoder.h",
+    "FlacDemuxer.h",
+    "FlacFrameParser.h",
+]
+
+UNIFIED_SOURCES += [
+    "FlacDecoder.cpp",
+    "FlacDemuxer.cpp",
+    "FlacFrameParser.cpp",
+]
+
+CXXFLAGS += CONFIG["MOZ_LIBVPX_CFLAGS"]
+
+FINAL_LIBRARY = "xul"
+
+# Add libFuzzer configuration directives
+include("/tools/fuzzing/libfuzzer-config.mozbuild")