PES Packet Parser. More...

#include <pes.h>

Public Member Functions
	cPes (const uint8_t *, int)
	Create a PES packet parser.

bool	IsValid (void)
	Check if the PES packet is valid.

bool	HasPts (void)
	Check if the PES packet contains a Presentation Time Stamp (PTS)

int64_t	GetPts (void)
	Get the Presentation Time Stamp (PTS) from the PES header.

const uint8_t *	GetPayload (void)
	Get a pointer to the PES payload data.

int	GetPayloadSize (void)
	Get the size of the PES payload.

int	GetPacketLength (void)
	Get the total length of the PES packet.

uint8_t	GetStreamId (void)

Protected Member Functions
virtual bool	IsStreamIdValid (void)=0

void	Init (void)
	Initialize and validate the PES packet.

bool	IsHeaderValid (void)
	Check if the PES header is valid.

Protected Attributes
bool	m_valid = false
	flag indicating if the PES packet is valid

const uint8_t *	m_data
	pointer to the raw PES packet data

int	m_size
	size of the PES packet

Static Protected Attributes
static constexpr uint32_t	PES_PACKET_START_CODE_PREFIX = 0x00'0001

static constexpr uint32_t	PES_PACKET_START_CODE_PREFIX_LEN = 3

Detailed Description

PES Packet Parser.

This class parses PES (Packetized Elementary Stream) packets to extract header information, PTS, and payload data.

Definition at line 30 of file pes.h.

Constructor & Destructor Documentation

◆ cPes()

cPes::cPes	(	const uint8_t *	data,
		int	size
	)

Create a PES packet parser.

Initializes the parser with a pointer to PES packet data and its size. The actual validation is performed by calling Init() in derived classes.

Parameters

data	Pointer to the raw PES packet data
size	Size of the PES packet in bytes

Definition at line 206 of file pes.cpp.

Member Function Documentation

◆ GetPacketLength()

int cPes::GetPacketLength ( void )

Get the total length of the PES packet.

Returns the complete size of the PES packet including both header and payload. The length is read from the PES packet header (bytes 4-5).

For packets with a specified length field (common for audio):

Returns the actual PES packet length from the header
Calculated as 6 + length_field (per H.222.0 standard)
The length_field specifies bytes after the 6-byte header prefix (3 bytes start code + 1 byte stream ID + 2 bytes length field)

For unbounded packets (length field = 0, common for video streams):

Returns the input buffer size (m_size)

Returns: Total size in bytes: actual packet length if specified, otherwise input buffer size

Definition at line 339 of file pes.cpp.

References m_data, and m_size.

◆ GetPayload()

const uint8_t * cPes::GetPayload ( void )

Get a pointer to the PES payload data.

Returns a pointer to the start of the payload data, skipping the PES header. For H.264/HEVC streams with a leading zero byte, the leading zero is also skipped.

Returns: Pointer to the payload data

Definition at line 304 of file pes.cpp.

References m_data.

◆ GetPayloadSize()

int cPes::GetPayloadSize ( void )

Get the size of the PES payload.

Calculates the size of the payload by subtracting the header size (and optional leading zero for H.264/HEVC) from the total packet size.

Returns: Size of the payload in bytes

Definition at line 317 of file pes.cpp.

References m_data, and m_size.

◆ GetPts()

int64_t cPes::GetPts ( void )

Get the Presentation Time Stamp (PTS) from the PES header.

Extracts the PTS value from the PES packet header if present. The PTS indicates when the decoded content should be presented.

Returns: The PTS value in 90 kHz units, or AV_NOPTS_VALUE if no PTS is present

Definition at line 288 of file pes.cpp.

References AV_NOPTS_VALUE, HasPts(), and m_data.

◆ GetStreamId()

uint8_t cPes::GetStreamId ( void )

inline

Definition at line 39 of file pes.h.

References m_data.

Referenced by Init(), cPesAudio::IsAudioStreamId(), cPesAudio::IsPrivateStreamId(), and cPesVideo::IsStreamIdValid().

◆ HasPts()

bool cPes::HasPts ( void )

Check if the PES packet contains a Presentation Time Stamp (PTS)

Examines the PES header flags to determine if a PTS is present in the packet. The PTS presence is indicated by specific bits in the PES header flags field.

Returns: true if the PES packet contains a PTS, false otherwise

Definition at line 275 of file pes.cpp.

References m_data.

Referenced by GetPts().

◆ Init()

void cPes::Init ( void )

protected

Initialize and validate the PES packet.

Performs validation checks on the PES packet structure:

Validates the PES header (start code prefix)
Checks if the stream ID matches the expected type (audio/video)
Ensures the packet has sufficient size for the header
Verifies the payload offset is within bounds

Sets m_valid to true if all checks pass. Called by derived class constructors.

Definition at line 222 of file pes.cpp.

References GetStreamId(), IsHeaderValid(), IsStreamIdValid(), LOGDEBUG, LOGWARNING, m_data, m_size, and m_valid.

Referenced by cPesAudio::cPesAudio(), and cPesVideo::cPesVideo().

◆ IsHeaderValid()

bool cPes::IsHeaderValid ( void )

protected

Check if the PES header is valid.

Validates that the PES packet has a valid header by checking:

The packet is long enough to contain a header
The start code prefix (0x000001) is present

Returns: true if the header is valid, false otherwise

Definition at line 262 of file pes.cpp.

References m_data, m_size, PES_PACKET_START_CODE_PREFIX, and ReadBytes().

Referenced by Init().

◆ IsStreamIdValid()

virtual bool cPes::IsStreamIdValid ( void )

protectedpure virtual

Implemented in cPesVideo, and cPesAudio.

Referenced by Init().

◆ IsValid()

bool cPes::IsValid ( void )

Check if the PES packet is valid.

Validates that the PES packet is well-formed and matches the expected stream type by checking:

The PES header is valid
The stream ID matches the expected stream type (video or audio)

The stream ID is masked with 0xF0 to check the stream type category (e.g., 0xE0 for video, 0xC0 for audio) while ignoring the low nibble which indicates the specific stream number.

Video streams have stream IDs in the range 0xE0-0xEF according to H.222.0 03/2017 Table 2-22, audio streams have IDs in the range 0xC0-0xCF.

Returns: true if the packet is valid and matches the expected stream type, false otherwise

Definition at line 248 of file pes.cpp.

References m_valid.

Member Data Documentation

◆ m_data

const uint8_t* cPes::m_data

protected

pointer to the raw PES packet data

Definition at line 47 of file pes.h.

Referenced by GetPacketLength(), GetPayload(), GetPayloadSize(), GetPts(), GetStreamId(), HasPts(), Init(), and IsHeaderValid().

◆ m_size

int cPes::m_size

protected

size of the PES packet

Definition at line 48 of file pes.h.

Referenced by GetPacketLength(), GetPayloadSize(), Init(), and IsHeaderValid().

◆ m_valid

bool cPes::m_valid = false

protected

flag indicating if the PES packet is valid

Definition at line 46 of file pes.h.

Referenced by Init(), and IsValid().

◆ PES_PACKET_START_CODE_PREFIX

constexpr uint32_t cPes::PES_PACKET_START_CODE_PREFIX = 0x00'0001

staticconstexprprotected

Definition at line 52 of file pes.h.

Referenced by IsHeaderValid().

◆ PES_PACKET_START_CODE_PREFIX_LEN

constexpr uint32_t cPes::PES_PACKET_START_CODE_PREFIX_LEN = 3

staticconstexprprotected

Definition at line 53 of file pes.h.

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

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ cPes()

Member Function Documentation

◆ GetPacketLength()

◆ GetPayload()

◆ GetPayloadSize()

◆ GetPts()

◆ GetStreamId()

◆ HasPts()

◆ Init()

◆ IsHeaderValid()

◆ IsStreamIdValid()

◆ IsValid()

Member Data Documentation

◆ m_data

◆ m_size

◆ m_valid

◆ PES_PACKET_START_CODE_PREFIX

◆ PES_PACKET_START_CODE_PREFIX_LEN