diff options
Diffstat (limited to 'dom/media/platforms/agnostic/bytestreams/Adts.h')
| -rw-r--r-- | dom/media/platforms/agnostic/bytestreams/Adts.h | 117 |
1 files changed, 112 insertions, 5 deletions
diff --git a/dom/media/platforms/agnostic/bytestreams/Adts.h b/dom/media/platforms/agnostic/bytestreams/Adts.h index c2b6b558b6..e6d20806ab 100644 --- a/dom/media/platforms/agnostic/bytestreams/Adts.h +++ b/dom/media/platforms/agnostic/bytestreams/Adts.h @@ -6,17 +6,124 @@ #define ADTS_H_ #include <stdint.h> +#include "MediaData.h" +#include "mozilla/Result.h" namespace mozilla { class MediaRawData; -class Adts { +namespace ADTS { + +// adts::FrameHeader - Holds the ADTS frame header and its parsing +// state. +// +// ADTS Frame Structure +// +// 11111111 1111BCCD EEFFFFGH HHIJKLMM MMMMMMMM MMMOOOOO OOOOOOPP(QQQQQQQQ +// QQQQQQQQ) +// +// Header consists of 7 or 9 bytes(without or with CRC). +// Letter Length(bits) Description +// { sync } 12 syncword 0xFFF, all bits must be 1 +// B 1 MPEG Version: 0 for MPEG-4, 1 for MPEG-2 +// C 2 Layer: always 0 +// D 1 protection absent, Warning, set to 1 if there is no +// CRC and 0 if there is CRC +// E 2 profile, the MPEG-4 Audio Object Type minus 1 +// F 4 MPEG-4 Sampling Frequency Index (15 is forbidden) +// H 3 MPEG-4 Channel Configuration (in the case of 0, the +// channel configuration is sent via an in-band PCE) +// M 13 frame length, this value must include 7 or 9 bytes of +// header length: FrameLength = +// (ProtectionAbsent == 1 ? 7 : 9) + size(AACFrame) +// O 11 Buffer fullness +// P 2 Number of AAC frames(RDBs) in ADTS frame minus 1, for +// maximum compatibility always use 1 AAC frame per ADTS +// frame +// Q 16 CRC if protection absent is 0 +class FrameHeader { public: - static int8_t GetFrequencyIndex(uint32_t aSamplesPerSecond); - static bool ConvertSample(uint16_t aChannelCount, int8_t aFrequencyIndex, - int8_t aProfile, mozilla::MediaRawData* aSample); - static bool RevertSample(MediaRawData* aSample); + uint32_t mFrameLength{}; + uint32_t mSampleRate{}; + uint32_t mSamples{}; + uint32_t mChannels{}; + uint8_t mObjectType{}; + uint8_t mSamplingIndex{}; + uint8_t mChannelConfig{}; + uint8_t mNumAACFrames{}; + bool mHaveCrc{}; + + // Returns whether aPtr matches a valid ADTS header sync marker + static bool MatchesSync(const Span<const uint8_t>& aData); + FrameHeader(); + // Header size + uint64_t HeaderSize() const; + bool IsValid() const; + // Resets the state to allow for a new parsing session. + void Reset(); + + // Returns whether the byte creates a valid sequence up to this point. + bool Parse(const Span<const uint8_t>& aData); }; +class Frame { + public: + Frame(); + + uint64_t Offset() const; + size_t Length() const; + // Returns the offset to the start of frame's raw data. + uint64_t PayloadOffset() const; + + size_t PayloadLength() const; + // Returns the parsed frame header. + const FrameHeader& Header() const; + bool IsValid() const; + // Resets the frame header and data. + void Reset(); + // Returns whether the valid + bool Parse(uint64_t aOffset, const uint8_t* aStart, const uint8_t* aEnd); + + private: + // The offset to the start of the header. + uint64_t mOffset; + // The currently parsed frame header. + FrameHeader mHeader; +}; + +class FrameParser { + public: + // Returns the currently parsed frame. Reset via Reset or EndFrameSession. + const Frame& CurrentFrame(); + // Returns the first parsed frame. Reset via Reset. + const Frame& FirstFrame() const; + // Resets the parser. Don't use between frames as first frame data is reset. + void Reset(); + // 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(uint64_t aOffset, const uint8_t* aStart, const uint8_t* aEnd); + + private: + // 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; +}; + +// Extract the audiospecificconfig from an ADTS header +void InitAudioSpecificConfig(const Frame& aFrame, MediaByteBuffer* aBuffer); +bool StripHeader(MediaRawData* aSample); +Result<uint8_t, bool> GetFrequencyIndex(uint32_t aSamplesPerSecond); +bool ConvertSample(uint16_t aChannelCount, uint8_t aFrequencyIndex, + uint8_t aProfile, mozilla::MediaRawData* aSample); +bool RevertSample(MediaRawData* aSample); +} // namespace ADTS } // namespace mozilla #endif |