CH264CCBitstreamParser Class Reference

Base class for H.264 closed caption bitstream parsers. More...

#include <H264CCBitstreamParser.h>

Inheritance diagram for CH264CCBitstreamParser:

Protected Member Functions
void	ProcessSEIPayload (std::span< const uint8_t > buf, double pts, std::vector< CCaptionBlock > &tempBuffer)
	Process SEI payload containing closed caption data.
CCPictureType	DetectSliceType (std::span< const uint8_t > buf)
	Detect slice type from H.264 slice header.

Additional Inherited Members
Public Member Functions inherited from ICCBitstreamParser
virtual	~ICCBitstreamParser ()=default
virtual CCPictureType	ParsePacket (DemuxPacket *pPacket, std::vector< CCaptionBlock > &tempBuffer, std::vector< CCaptionBlock > &reorderBuffer)=0
	Parse a video packet and extract closed caption data.
virtual const char *	GetName () const =0
	Get parser name for debugging/logging.

Detailed Description

Base class for H.264 closed caption bitstream parsers.

Provides shared functionality for parsing H.264 SEI (Supplemental Enhancement Information) payloads containing CEA-608/708 closed caption data.

H.264 CC data is embedded in SEI NAL units (type 6) with payload type 4 (user_data_registered_itu_t_t35). The data may be prefixed with ITU-T T.35 country/provider codes or contain GA94 data directly.

Member Function Documentation

DetectSliceType()

CCPictureType CH264CCBitstreamParser::DetectSliceType ( std::span< const uint8_t > buf )

protected

Detect slice type from H.264 slice header.

Parses the slice header to determine if this is an I-slice, P-slice, or B-slice. Used to determine when to decode CC data (I/P frames only).

Parameters

buf	Pointer to slice NAL unit data (after NAL header)
len	Length of slice data

Returns

Picture type (I_FRAME, P_FRAME, OTHER, or INVALID if parsing fails)

ProcessSEIPayload()

void CH264CCBitstreamParser::ProcessSEIPayload ( std::span< const uint8_t > buf, double pts, std::vector< CCaptionBlock > & tempBuffer )

protected

Process SEI payload containing closed caption data.

Searches for GA94 closed caption payload within SEI user data. Handles both:

• ITU-T T.35 format: country_code(1) + provider_code(2) + 'GA94'...
• Direct GA94 format: 'GA94'...

Parameters

buf	Pointer to SEI payload data
len	Length of SEI payload
pts	Presentation timestamp for CC data
tempBuffer	Temporary buffer for CC data (for reordering)

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

• H264CCBitstreamParser.h
• H264CCBitstreamParser.cpp