Audio stream reassembly buffer. More...

#include <pes.h>

Collaboration diagram for cReassemblyBufferAudio:

Public Member Functions
	cReassemblyBufferAudio ()

AVPacket *	PopAvPacket () override
	Pop an audio AVPacket from the reassembly buffer. More...

AVCodecID	TruncateBufferUntilFirstValidData ()
	Truncate buffer until the first valid audio frame. More...

SyncWordInfo	FindSyncWord (const uint8_t *, int)
	Find the first audio sync word in data. More...

AVCodecID	DetectCodecFromSyncWord (const uint8_t *, int)
	Detect audio codec from sync word pattern. More...

int	GetFrameSizeForCodec (AVCodecID, const uint8_t *)
	Get the frame size for a given codec and frame header. More...

Public Member Functions inherited from cReassemblyBuffer
virtual void	Push (const uint8_t *data, int size, int64_t pts)

virtual AVPacket *	PopAvPacket ()=0

bool	IsEmpty ()

size_t	GetSize ()

void	Reset ()
	Reset the reassembly buffer. More...

AVCodecID	GetCodec ()

Private Member Functions
SyncWordInfo	FindTwoConsecutiveFramesWithSameSyncWord ()
	Find two consecutive audio frames with the same sync word. More...

Private Attributes
bool	m_ptsInvalid = false
	flag indicating if PTS is invalid for current buffer, because it was truncated More...

Static Private Attributes
static constexpr int	MAX_HEADER_SIZE = 6

Additional Inherited Members
Protected Member Functions inherited from cReassemblyBuffer
	cReassemblyBuffer (const char *identifier)

AVPacket *	PopAvPacket (int)
	Pop an AVPacket from the reassembly buffer. More...

Protected Attributes inherited from cReassemblyBuffer
AVCodecID	m_codec = AV_CODEC_ID_NONE
	detected codec ID More...

cPtsTrackingBuffer	m_buffer
	fragmentation buffer More...

int64_t	m_lastPoppedPts = AV_NOPTS_VALUE
	PTS of the last popped AVPacket. More...

Detailed Description

Audio stream reassembly buffer.

Reassembles audio elementary streams by detecting sync words and validating frame headers. Supports MP2, AAC (LATM/ADTS), AC3, and E-AC3 codecs.

Definition at line 172 of file pes.h.

Constructor & Destructor Documentation

◆ cReassemblyBufferAudio()

cReassemblyBufferAudio::cReassemblyBufferAudio ( )

inline

Definition at line 174 of file pes.h.

Member Function Documentation

◆ DetectCodecFromSyncWord()

AVCodecID cReassemblyBufferAudio::DetectCodecFromSyncWord	(	const uint8_t *	syncWord,
		int	size
	)

Detect audio codec from sync word pattern.

Checks if the data starts with a valid sync word for any supported audio codec. Uses the AudioCodecMap to test sync word patterns for MP2, AAC LATM, AAC ADTS, AC3, and E-AC3.

Parameters

syncWord	Pointer to potential sync word data
size	Size of available data

Returns: Detected AVCodecID, or AV_CODEC_ID_NONE if no match

Definition at line 595 of file pes.cpp.

References AudioCodecMap.

Referenced by FindSyncWord(), FindTwoConsecutiveFramesWithSameSyncWord(), and TEST_CASE().

◆ FindSyncWord()

SyncWordInfo cReassemblyBufferAudio::FindSyncWord	(	const uint8_t *	data,
		int	size
	)

Find the first audio sync word in data.

Scans the data byte-by-byte looking for any recognized audio sync word pattern. Checks all supported audio codecs (MP2, AAC LATM, AAC ADTS, AC3, E-AC3).

Parameters

data	Pointer to audio data
size	Size of the data in bytes

Returns: SyncWordInfo with detected codec and position, or AV_CODEC_ID_NONE if not found

Definition at line 573 of file pes.cpp.

References DetectCodecFromSyncWord().

Referenced by FindTwoConsecutiveFramesWithSameSyncWord(), and TEST_CASE().

◆ FindTwoConsecutiveFramesWithSameSyncWord()

SyncWordInfo cReassemblyBufferAudio::FindTwoConsecutiveFramesWithSameSyncWord ( )

private

Find two consecutive audio frames with the same sync word.

Searches the buffer for a valid audio frame followed immediately by another frame of the same codec. This validates that the sync word and frame header are genuine and not false positives in random data.

The function modifies the buffer internally by erasing false positives as it searches. When no sync word is found, it keeps the last MAX_HEADER_SIZE bytes.

Returns: SyncWordInfo with codec ID and position, or AV_CODEC_ID_NONE if not found

Definition at line 526 of file pes.cpp.

References AudioCodecMap, SyncWordInfo::codecId, DetectCodecFromSyncWord(), cPtsTrackingBuffer::Erase(), FindSyncWord(), cPtsTrackingBuffer::GetSize(), cReassemblyBuffer::m_buffer, MAX_HEADER_SIZE, cPtsTrackingBuffer::Peek(), and SyncWordInfo::pos.

Referenced by TruncateBufferUntilFirstValidData().

◆ GetFrameSizeForCodec()

int cReassemblyBufferAudio::GetFrameSizeForCodec	(	AVCodecID	codec,
		const uint8_t *	data
	)

Get the frame size for a given codec and frame header.

Calculates the frame size by parsing the codec-specific frame header. Only used for testing purposes to expose the AudioCodecMap frame size calculation.

Parameters

codec	The audio codec ID
data	Pointer to the frame header data

Returns: Frame size in bytes

Exceptions

std::out_of_range	if codec is not in AudioCodecMap
std::invalid_argument	if frame header is invalid

Definition at line 619 of file pes.cpp.

References AudioCodecMap.

Referenced by TEST_CASE().

◆ PopAvPacket()

AVPacket * cReassemblyBufferAudio::PopAvPacket ( )

overridevirtual

Pop an audio AVPacket from the reassembly buffer.

Truncates the buffer to the first valid audio frame, detects the codec, and pops a complete audio frame as an AVPacket.

Returns: Allocated AVPacket with one audio frame, or nullptr if no valid frame found

Implements cReassemblyBuffer.

Definition at line 461 of file pes.cpp.

References AudioCodecMap, AV_NOPTS_VALUE, LOGERROR, LOGWARNING, cReassemblyBuffer::m_buffer, cReassemblyBuffer::m_codec, m_ptsInvalid, cPtsTrackingBuffer::Peek(), cReassemblyBuffer::PopAvPacket(), and TruncateBufferUntilFirstValidData().

Referenced by cSoftHdDevice::PlayAudio().

◆ TruncateBufferUntilFirstValidData()

AVCodecID cReassemblyBufferAudio::TruncateBufferUntilFirstValidData ( )

Truncate buffer until the first valid audio frame.

Searches for two consecutive audio frames with the same sync word to validate the frame header, then erases all data before the first valid frame. This removes garbage data and synchronizes to the audio stream.

Returns: Detected codec ID, or AV_CODEC_ID_NONE if no valid frames found

Definition at line 499 of file pes.cpp.

References SyncWordInfo::codecId, cPtsTrackingBuffer::Erase(), FindTwoConsecutiveFramesWithSameSyncWord(), cPtsTrackingBuffer::GetSize(), LOGDEBUG, cReassemblyBuffer::m_buffer, m_ptsInvalid, and SyncWordInfo::pos.

Referenced by PopAvPacket(), and TEST_CASE().

Member Data Documentation

◆ m_ptsInvalid

bool cReassemblyBufferAudio::m_ptsInvalid = false

private

flag indicating if PTS is invalid for current buffer, because it was truncated

Definition at line 183 of file pes.h.

Referenced by PopAvPacket(), and TruncateBufferUntilFirstValidData().

◆ MAX_HEADER_SIZE

constexpr int cReassemblyBufferAudio::MAX_HEADER_SIZE = 6

staticconstexprprivate

Definition at line 182 of file pes.h.

Referenced by FindTwoConsecutiveFramesWithSameSyncWord().

The documentation for this class was generated from the following files:

Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ cReassemblyBufferAudio()

Member Function Documentation

◆ DetectCodecFromSyncWord()

◆ FindSyncWord()

◆ FindTwoConsecutiveFramesWithSameSyncWord()

◆ GetFrameSizeForCodec()

◆ PopAvPacket()

◆ TruncateBufferUntilFirstValidData()

Member Data Documentation

◆ m_ptsInvalid

◆ MAX_HEADER_SIZE