ByteReader Namespace Reference

These functions are rewritten copies from FFmpeg's libavcodec, where find_start_code() is prefixed with avpriv_ . More...

Functions
bool	start_code_is_valid (uint32_t start_code)
	Test whether a start code found by find_start_code() is valid. More...
const MTV_PUBLIC uint8_t *	find_start_code (const uint8_t *p, const uint8_t *end, uint32_t *start_code)
	Find the first start code in the buffer p. More...
const MTV_PUBLIC uint8_t *	find_start_code_truncated (const uint8_t *p, const uint8_t *end, uint32_t *start_code)
	By preserving the start_code value between subsequent calls, the caller can detect start codes across buffer boundaries. More...

Detailed Description

These functions are rewritten copies from FFmpeg's libavcodec, where find_start_code() is prefixed with avpriv_ .

Function Documentation

start_code_is_valid()

bool ByteReader::start_code_is_valid ( uint32_t  start_code )

inline

Test whether a start code found by find_start_code() is valid.

Use this to test the validity of a start code especially if a start code can be at the end of the buffer, where testing the return value of find_start_code() would incorrectly imply that the start code is invalid (since the returned value equals end ).

Parameters

[in]

start_code

The start code to test.

Returns

A boolean that is true if and only if start_code is valid

Definition at line 54 of file bytereader.h.

Referenced by AVCParser::addBytes(), HEVCParser::addBytes(), find_start_code_truncated(), DTVRecorder::FindMPEG2Keyframes(), DTVRecorder::FindPSKeyFrames(), and PTSListener::ProcessTSPacket().

find_start_code()

const uint8_t * ByteReader::find_start_code	(	const uint8_t *	p,
		const uint8_t *	end,
		uint32_t *	start_code
	)

Find the first start code in the buffer p.

A start code is a sequence of 4 bytes with the hexadecimal value 00 00 01 XX , where XX represents any value and memory address increases left to right.

Parameters

[in]	p	A pointer to the start of the memory buffer to scan.
[in]	end	A pointer to the past-the-end memory address for the buffer given by p. p must be ≤ end.
[out]	start_code	A pointer to a mutable uint32_t. Set to the found start code if it exists or an invalid start code (the 4 bytes prior to the returned value or ~0 if ).

Returns

A pointer to the memory address following the found start code, or end if no start code was found.

Definition at line 26 of file bytereader.cpp.

Referenced by find_start_code_truncated().

find_start_code_truncated()

const uint8_t * ByteReader::find_start_code_truncated	(	const uint8_t *	p,
		const uint8_t *	end,
		uint32_t *	start_code
	)

By preserving the start_code value between subsequent calls, the caller can detect start codes across buffer boundaries.

Parameters

[in,out]

start_code

A pointer to a mutable uint32_t. As input: For no history preset to ~0 , otherwise preset to the last returned start code to enable detecting start codes across buffer boundaries. On output: Set to the found start code if it exists or an invalid start code (the 4 bytes prior to the returned value, using the input history if ).

See also

find_start_code()

Definition at line 74 of file bytereader.cpp.

Referenced by AVCParser::addBytes(), HEVCParser::addBytes(), DTVRecorder::FindMPEG2Keyframes(), DTVRecorder::FindPSKeyFrames(), AvFormatDecoder::MpegPreProcessPkt(), and PTSListener::ProcessTSPacket().