nal.h File Reference

A generic NAL (Network Abstraction Layer) representation. More...

#include <compy/nal/h264.h>
#include <compy/nal/h265.h>
#include <stdbool.h>
#include <stdint.h>
#include <datatype99.h>
#include <slice99.h>
#include <compy/priv/compiler_attrs.h>

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Data Structures
struct	Compy_NalUnit
	A generic NAL unit (either H.264 or H.265). More...

Typedefs
typedef size_t(*	Compy_NalStartCodeTester) (U8Slice99 data)
	A function that tests whether data starts with some start code.

Functions
	datatype99 (Compy_NalHeader,(Compy_NalHeader_H264, Compy_H264NalHeader),(Compy_NalHeader_H265, Compy_H265NalHeader))
	A generic NAL header (either H.264 or H.265).
uint8_t	Compy_NalHeader_unit_type (Compy_NalHeader self) COMPY_PRIV_MUST_USE
	Returns the NAL unit type of self.
size_t	Compy_NalHeader_size (Compy_NalHeader self) COMPY_PRIV_MUST_USE
	Computes the size of self in bytes.
size_t	Compy_NalHeader_fu_size (Compy_NalHeader self) COMPY_PRIV_MUST_USE
	Computes the size of a fragmentation unit (FU) header self.
bool	Compy_NalHeader_is_vps (Compy_NalHeader self) COMPY_PRIV_MUST_USE
	Checks whether self is VPS.
bool	Compy_NalHeader_is_sps (Compy_NalHeader self) COMPY_PRIV_MUST_USE
	Checks whether self is SPS.
bool	Compy_NalHeader_is_pps (Compy_NalHeader self) COMPY_PRIV_MUST_USE
	Checks whether self is PPS.
bool	Compy_NalHeader_is_coded_slice_idr (Compy_NalHeader self) COMPY_PRIV_MUST_USE
	Checks whether self is a coded slice IDR.
bool	Compy_NalHeader_is_coded_slice_non_idr (Compy_NalHeader self) COMPY_PRIV_MUST_USE
	Checks whether self is a coded slice non-IDR.
void	Compy_NalHeader_serialize (Compy_NalHeader self, uint8_t buffer[restrict])
	Writes the binary representation of self into buffer.
void	Compy_NalHeader_write_fu_header (Compy_NalHeader self, uint8_t buffer[restrict], bool is_first_fragment, bool is_last_fragment)
	Writes a FU header of self to buffer.
uint8_t	compy_nal_fu_header (bool is_first_fragment, bool is_last_fragment, uint8_t unit_type) COMPY_PRIV_MUST_USE
	Creates a generic NAL FU header.
Compy_NalStartCodeTester	compy_determine_start_code (U8Slice99 data) COMPY_PRIV_MUST_USE
	Returns a start code tester for data.
size_t	compy_test_start_code_3b (U8Slice99 data)
	The 3-byte start code tester (0x000001).
size_t	compy_test_start_code_4b (U8Slice99 data)
	The 3-byte start code tester (0x00000001).

Detailed Description

A generic NAL (Network Abstraction Layer) representation.

Typedef Documentation

Compy_NalStartCodeTester

typedef size_t(* Compy_NalStartCodeTester) (U8Slice99 data)

A function that tests whether data starts with some start code.

Returns

The number of start code bytes. If there is no start code in the beginning of data, returns 0.

See also

compy_test_start_code_3b

compy_test_start_code_4b

Function Documentation

compy_determine_start_code()

Compy_NalStartCodeTester compy_determine_start_code

(

U8Slice99

data

)

Returns a start code tester for data.

If data does not begin with a start code (either 0x000001 or 0x00000001), returns NULL.

This function is useful when you have some *.h264 bitstream file and you want to determine what start code it uses – just pass the beginning of this file to compy_determine_start_code and invoke the returned tester multiple times afterwards.

Compy_NalHeader_fu_size()

size_t Compy_NalHeader_fu_size

(

Compy_NalHeader

self

)

Computes the size of a fragmentation unit (FU) header self.

See also

H.264 Fragmentation Units (FUs): https://datatracker.ietf.org/doc/html/rfc6184#section-5.8

H.265 Fragmentation Units (FUs): https://datatracker.ietf.org/doc/html/rfc7798#section-4.4.3

Compy_NalHeader_serialize()

void Compy_NalHeader_serialize	(	Compy_NalHeader	self,
		uint8_t	buffer[restrict]
	)

Writes the binary representation of self into buffer.

Parameters

[in]	self	The header to write.
[out]	buffer	The memory area capable of storing Compy_NalHeader_size(self) bytes.

Compy_NalHeader_write_fu_header()

void Compy_NalHeader_write_fu_header	(	Compy_NalHeader	self,
		uint8_t	buffer[restrict],
		bool	is_first_fragment,
		bool	is_last_fragment
	)

Writes a FU header of self to buffer.

Parameters

[in]	self	The header to write.
[out]	buffer	The memory area capable of storing Compy_NalHeader_fu_size(self) bytes.
[in]	is_first_fragment	The indication of a start of the FU.
[in]	is_last_fragment	The indication of an end of the FU.

See also

H.264 Fragmentation Units (FUs): https://datatracker.ietf.org/doc/html/rfc6184#section-5.8

H.265 Fragmentation Units (FUs): https://datatracker.ietf.org/doc/html/rfc7798#section-4.4.3

datatype99()

datatype99	(	Compy_NalHeader	,
		(Compy_NalHeader_H264, Compy_H264NalHeader)	,
		(Compy_NalHeader_H265, Compy_H265NalHeader)
	)

A generic NAL header (either H.264 or H.265).

See Datatype99 for the macro usage.