Declarations of utilities for creating and parsing payloads formatted according to the CDI Ancillary Data Format Specification (https://cdi.elemental.com/specs/baseline-ancillary-data). More...

#include "cdi_avm_payloads_api.h"
#include <stdint.h>
#include <stdbool.h>

Data Structures
struct	AncillaryDataPacket
	The ANC data packet. See https://datatracker.ietf.org/doc/html/rfc8331#section-2.1 for details. More...

struct	AncillaryDataPayloadErrors
	Counters for keeping track of errors observed when parsing ANC payloads. More...

struct	AncillaryDataPayloadHeader
	The ANC payload header. More...

Functions
static bool	Parity8 (uint8_t value)

static uint16_t	WithParityBits (uint8_t value)

static uint8_t	CheckParityBits (uint16_t raw_word, int *parity_errors_ptr)

void	ParseAncillaryDataPayloadHeader (const uint32_t payload_net_data_ptr, uint16_t packet_count_ptr, CdiFieldKind *field_kind_ptr)

void	ParseAncillaryDataPacketHeader (const uint32_t packet_net_data_ptr, struct AncillaryDataPacket packet_ptr, struct AncillaryDataPayloadErrors *payload_errors)

int	ParseAncillaryDataPacket (const uint32_t packet_net_data_ptr, struct AncillaryDataPacket packet_ptr, struct AncillaryDataPayloadErrors *payload_errors_ptr)

int	GetAncillaryDataPacketSize (int data_count)

void	WriteAncillaryDataPayloadHeader (uint32_t *payload_net_data_ptr, uint16_t packet_count, CdiFieldKind field_kind)

void	WriteAncillaryDataPacketHeader (uint32_t packet_net_data_ptr, const struct AncillaryDataPacket packet_ptr, uint32_t *checksum_ptr)

int	WriteAncillaryDataPacket (uint32_t packet_net_data_ptr, const struct AncillaryDataPacket packet_ptr)

Detailed Description

Declarations of utilities for creating and parsing payloads formatted according to the CDI Ancillary Data Format Specification (https://cdi.elemental.com/specs/baseline-ancillary-data).

Ancillary data payloads contain one or more ancillarry data packets (ANC packets). Each ANC packet compactly contains user data in 10-bit words. An ANC packet may contain up to 255 user data words. The meaning of these words is determined by the DID and SDID fields in an ANC packet header. See https://smpte-ra.org/smpte-ancillary-data-smpte-st-291 for current assignments.

Function Documentation

◆ CheckParityBits()

static uint8_t CheckParityBits	(	uint16_t	raw_word,
		int *	parity_errors_ptr )

inlinestatic

Check the parity bits of an 8-bit value in the 10-bit input data.

Parameters

raw_word	10-bit raw word
parity_errors_ptr	Pointer to payload error counts.

Returns: 8-bit value (bits b7-b0 of raw_word).

◆ GetAncillaryDataPacketSize()

int GetAncillaryDataPacketSize ( int data_count )

Calculate number of 32-bit words needed to write an ancillary data packet.

Parameters

data_count The number of user data words in the ANC packet.

Returns: The number of 32-bit words required to store an ANC packet with data_count user data words.

◆ Parity8()

static bool Parity8 ( uint8_t value )

inlinestatic

Return parity bit of a byte.

Parameters

value The value for which to calculate the parity bit.

Returns: The parity bit of value.

◆ ParseAncillaryDataPacket()

int ParseAncillaryDataPacket	(	const uint32_t *	packet_net_data_ptr,
		struct AncillaryDataPacket *	packet_ptr,
		struct AncillaryDataPayloadErrors *	payload_errors_ptr )

Parse and ancillary data packet.

Parameters

packet_net_data_ptr	Pointer to a received ANC packet contained in an ANC payload. In network byte order. Input.
packet_ptr	Pointer to an ANC packet. Output.
payload_errors_ptr	Pointer to error counters.

Returns: Offset from packet_net_data_ptr to the beginning of the next ANC packet.

◆ ParseAncillaryDataPacketHeader()

void ParseAncillaryDataPacketHeader	(	const uint32_t *	packet_net_data_ptr,
		struct AncillaryDataPacket *	packet_ptr,
		struct AncillaryDataPayloadErrors *	payload_errors )

Parse the header of an ancillary data packet.

Parameters

packet_net_data_ptr	Pointer to a received ANC packet contained in an ANC payload. In network byte order. Input.
packet_ptr	Pointer to an ANC packet structure. Output.
payload_errors	Pointer to error counters.

Returns: Part of the packet's first user data word or zero when the packet is empty.

◆ ParseAncillaryDataPayloadHeader()

void ParseAncillaryDataPayloadHeader	(	const uint32_t *	payload_net_data_ptr,
		uint16_t *	packet_count_ptr,
		CdiFieldKind *	field_kind_ptr )

Parse the header of a received ancillary data payload.

Parameters

payload_net_data_ptr	Pointer to received ancillary data. In network byte order. Input.
packet_count_ptr	Pointer to number of ancillary data packets in payload. Output.
field_kind_ptr	Pointer to field kind associated with payload. Output.

◆ WithParityBits()

static uint16_t WithParityBits ( uint8_t value )

inlinestatic

Return 8-bit value with two parity bits.

Parameters

value The value to augment with parity bits.

Returns: 10-bit word: 8-bit value and two parity bits.

◆ WriteAncillaryDataPacket()

int WriteAncillaryDataPacket	(	uint32_t *	packet_net_data_ptr,
		const struct AncillaryDataPacket *	packet_ptr )

Write an ancillary data packet for transmission in network byte order.

Parameters

packet_net_data_ptr	Pointer into transmit buffer to start of an ANC packet. In network byte order. Output.
packet_ptr	Pointer to ANC packet. Input.

Returns: Offset from packet_net_data_ptr to the start of the next ancillary data packet to write.

◆ WriteAncillaryDataPacketHeader()

void WriteAncillaryDataPacketHeader	(	uint32_t *	packet_net_data_ptr,
		const struct AncillaryDataPacket *	packet_ptr,
		uint32_t *	checksum_ptr )

Write an ancillary data packet header for transmission in network byte order.

Parameters

packet_net_data_ptr	Pointer into transmit buffer to start of an ANC packet. In network byte order. Output.
packet_ptr	Pointer to an ANC packet. Input.
checksum_ptr	Pointer to running checksum. Output.

◆ WriteAncillaryDataPayloadHeader()

void WriteAncillaryDataPayloadHeader	(	uint32_t *	payload_net_data_ptr,
		uint16_t	packet_count,
		CdiFieldKind	field_kind )

Write an ancillary data payload header for transmission in network byte order.

Parameters

payload_net_data_ptr	Pointer to transmit buffer for an ANC payload. In network byte order. Output.
packet_count	Number of ancillary data packets in payload. Input.
field_kind	Field kind associated with payload. Input.

Data Structures

Functions

Detailed Description

Function Documentation

◆ CheckParityBits()

◆ GetAncillaryDataPacketSize()

◆ Parity8()

◆ ParseAncillaryDataPacket()

◆ ParseAncillaryDataPacketHeader()

◆ ParseAncillaryDataPayloadHeader()

◆ WithParityBits()

◆ WriteAncillaryDataPacket()

◆ WriteAncillaryDataPacketHeader()

◆ WriteAncillaryDataPayloadHeader()