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Diffstat (limited to 'dom/media/MP3Demuxer.h')
| -rw-r--r-- | dom/media/MP3Demuxer.h | 474 |
1 files changed, 474 insertions, 0 deletions
diff --git a/dom/media/MP3Demuxer.h b/dom/media/MP3Demuxer.h new file mode 100644 index 000000000..03e67b0d9 --- /dev/null +++ b/dom/media/MP3Demuxer.h @@ -0,0 +1,474 @@ +/* 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 "mozilla/Attributes.h" +#include "mozilla/Maybe.h" +#include "MediaDataDemuxer.h" +#include "MediaResource.h" +#include "mp4_demuxer/ByteReader.h" +#include <vector> + +namespace mozilla { +namespace mp3 { + +class MP3TrackDemuxer; + +class MP3Demuxer : public MediaDataDemuxer { +public: + // MediaDataDemuxer interface. + explicit MP3Demuxer(MediaResource* aSource); + RefPtr<InitPromise> Init() override; + bool HasTrackType(TrackInfo::TrackType aType) const 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; +}; + +// 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 http://id3.org/id3v2.3.0. +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; + + // 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; + + // Returns the size of an ID3v2.4 footer if present and zero otherwise. + uint8_t FooterSize() 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. + uint32_t mSize; + + // The current byte position in the parsed sequence. Reset via Reset and + // incremented via Update. + int mPos; + }; + + // Returns the parsed ID3 header. Note: check for validity. + const ID3Header& Header() const; + + // Parses contents of given ByteReader for a valid ID3v2 header. + // Returns the total ID3v2 tag size if successful and zero otherwise. + uint32_t Parse(mp4_demuxer::ByteReader* aReader); + + // Resets the state to allow for a new parsing session. + void Reset(); + +private: + // The currently parsed ID3 header. Reset via Reset, updated via Parse. + ID3Header mHeader; +}; + +// 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. + int32_t SampleRate() const; + + // Number of audio channels. + int32_t Channels() const; + + // Samples per frames, static depending on MPEG version and layer. + int32_t SamplesPerFrame() const; + + // Slot size used for padding, static depending on MPEG layer. + int32_t SlotSize() const; + + // Bitrate in kbps, can vary between frames. + int32_t Bitrate() const; + + // MPEG layer (0->invalid, 1->I, 2->II, 3->III). + int32_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; + }; + + // 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(float aDurationFac) 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(mp4_demuxer::ByteReader* aReader); + + 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. + bool ParseXing(mp4_demuxer::ByteReader* aReader); + + // 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. + bool ParseVBRI(mp4_demuxer::ByteReader* 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; + }; + + // 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. + int32_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 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 ByteReader 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. + bool Parse(mp4_demuxer::ByteReader* aReader, uint32_t* aBytesToSkip); + + // 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. + bool ParseVBRHeader(mp4_demuxer::ByteReader* 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; +}; + +// The MP3 demuxer used to extract MPEG frames and side information out of +// MPEG streams. +class MP3TrackDemuxer : public MediaTrackDemuxer { +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::TimeUnit 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(media::TimeUnit aTime) override; + RefPtr<SamplesPromise> GetSamples(int32_t aNumSamples = 1) override; + void Reset() override; + RefPtr<SkipAccessPointPromise> SkipToNextRandomAccessPoint( + media::TimeUnit aTimeThreshold) override; + int64_t GetResourceOffset() const override; + media::TimeIntervals GetBuffered() override; + +private: + // Destructor. + ~MP3TrackDemuxer() {} + + // 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. + int32_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) MPEG resource. + MediaResourceIndex mSource; + + // MPEG frame parser used to detect frames and extract side info. + FrameParser mParser; + + // 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. + uint64_t mTotalFrameLen; + + // Samples per frame metric derived from frame headers or 0 if none available. + int32_t mSamplesPerFrame; + + // Samples per second metric derived from frame headers or 0 if none available. + int32_t mSamplesPerSecond; + + // Channel count derived from frame headers or 0 if none available. + int32_t mChannels; + + // Audio track config info. + UniquePtr<AudioInfo> mInfo; +}; + +} // namespace mp3 +} // namespace mozilla + +#endif |