rtp_transport.h File Reference

An RTP data transport. More...

#include <compy/droppable.h>
#include <compy/transport.h>
#include <stdbool.h>
#include <stdint.h>
#include <datatype99.h>
#include <slice99.h>
#include <compy/priv/compiler_attrs.h>

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Typedefs
typedef struct Compy_RtpTransport	Compy_RtpTransport
	An RTP data transport.

Functions
	datatype99 (Compy_RtpTimestamp,(Compy_RtpTimestamp_Raw, uint32_t),(Compy_RtpTimestamp_SysClockUs, uint64_t))
	An RTP timestamp.
Compy_RtpTransport *	Compy_RtpTransport_new (Compy_Transport t, uint8_t payload_ty, uint32_t clock_rate) COMPY_PRIV_MUST_USE
	Creates a new RTP transport from the underlying level-4 protocol t.
int	Compy_RtpTransport_send_packet (Compy_RtpTransport *self, Compy_RtpTimestamp ts, bool marker, U8Slice99 payload_header, U8Slice99 payload) COMPY_PRIV_MUST_USE
	Sends an RTP packet.
	declImplExtern99 (Compy_Droppable, Compy_RtpTransport)
	Implements Compy_Droppable_IFACE for Compy_RtpTransport.
bool	Compy_RtpTransport_is_full (Compy_RtpTransport *self)
uint32_t	Compy_RtpTransport_get_ssrc (const Compy_RtpTransport *self)
	Returns the SSRC identifier of this transport.
void	Compy_RtpTransport_set_ssrc (Compy_RtpTransport *self, uint32_t ssrc)
	Sets the SSRC identifier of this transport.
void	Compy_RtpTransport_set_extension (Compy_RtpTransport *self, uint8_t id, const uint8_t *value, uint8_t len)
	Sets a persistent one-byte RTP header extension (RFC 8285).
uint16_t	Compy_RtpTransport_get_seq (const Compy_RtpTransport *self)
	Returns the current RTP sequence number of this transport.
uint32_t	Compy_RtpTransport_get_packet_count (const Compy_RtpTransport *self)
	Returns the total number of RTP packets sent.
uint32_t	Compy_RtpTransport_get_octet_count (const Compy_RtpTransport *self)
	Returns the total number of payload octets sent (excludes RTP headers).
uint32_t	Compy_RtpTransport_get_last_rtp_timestamp (const Compy_RtpTransport *self)
	Returns the RTP timestamp of the last sent packet.
uint32_t	Compy_RtpTransport_get_rtp_timestamp_now (const Compy_RtpTransport *self)
	Returns the RTP timestamp extrapolated to the current instant.

Detailed Description

An RTP data transport.

Function Documentation

Compy_RtpTransport_get_last_rtp_timestamp()

uint32_t Compy_RtpTransport_get_last_rtp_timestamp

(

const Compy_RtpTransport *

self

)

Returns the RTP timestamp of the last sent packet.

Precondition

self != NULL

Compy_RtpTransport_get_octet_count()

uint32_t Compy_RtpTransport_get_octet_count

(

const Compy_RtpTransport *

self

)

Returns the total number of payload octets sent (excludes RTP headers).

Precondition

self != NULL

Compy_RtpTransport_get_packet_count()

uint32_t Compy_RtpTransport_get_packet_count

(

const Compy_RtpTransport *

self

)

Returns the total number of RTP packets sent.

Precondition

self != NULL

Compy_RtpTransport_get_rtp_timestamp_now()

uint32_t Compy_RtpTransport_get_rtp_timestamp_now

(

const Compy_RtpTransport *

self

)

Returns the RTP timestamp extrapolated to the current instant.

Uses the last sent RTP timestamp plus elapsed time since that send, scaled by the clock rate. This gives the RTP clock value at "now," suitable for RTCP SR where the NTP and RTP timestamps must represent the same instant (RFC 3550 Section 6.4.1).

Precondition

self != NULL

Compy_RtpTransport_get_seq()

uint16_t Compy_RtpTransport_get_seq

(

const Compy_RtpTransport *

self

)

Returns the current RTP sequence number of this transport.

Precondition

self != NULL

Compy_RtpTransport_get_ssrc()

uint32_t Compy_RtpTransport_get_ssrc

(

const Compy_RtpTransport *

self

)

Returns the SSRC identifier of this transport.

Precondition

self != NULL

Compy_RtpTransport_new()

Compy_RtpTransport * Compy_RtpTransport_new	(	Compy_Transport	t,
		uint8_t	payload_ty,
		uint32_t	clock_rate
	)

Creates a new RTP transport from the underlying level-4 protocol t.

Parameters

[in]	t	The level-4 protocol (such as TCP or UDP).
[in]	payload_ty	The RTP payload type. The list of payload types is available here: https://en.wikipedia.org/wiki/RTP_payload_formats.
[in]	clock_rate	The RTP clock rate of payload_ty (HZ).

Precondition

t.self && t.vptr

The rand PRNG must be set up via srand.

Compy_RtpTransport_send_packet()

int Compy_RtpTransport_send_packet	(	Compy_RtpTransport *	self,
		Compy_RtpTimestamp	ts,
		bool	marker,
		U8Slice99	payload_header,
		U8Slice99	payload
	)

Sends an RTP packet.

Parameters

[out]	self	The RTP transport for sending this packet.
[in]	ts	The RTP timestamp for this packet.
[in]	marker	The RTP marker flag.
[in]	payload_header	The payload header. Can be U8Slice99_empty().
[in]	payload	The payload data.

Precondition

self != NULL

Returns

-1 if an I/O error occurred and sets errno appropriately, 0 on success.

Compy_RtpTransport_set_extension()

void Compy_RtpTransport_set_extension	(	Compy_RtpTransport *	self,
		uint8_t	id,
		const uint8_t *	value,
		uint8_t	len
	)

Sets a persistent one-byte RTP header extension (RFC 8285).

The extension is included in every outgoing packet. Profile is 0xBEDE (one-byte header format). The extension element is: [id(4 bits) | len-1(4 bits) | value(len bytes)].

Parameters

[in]	id	Extension ID (1-14).
[in]	value	Extension value bytes.
[in]	len	Length of value (1-8 bytes).

Precondition

self != NULL

id >= 1 && id <= 14

len >= 1 && len <= 8

Compy_RtpTransport_set_ssrc()

void Compy_RtpTransport_set_ssrc	(	Compy_RtpTransport *	self,
		uint32_t	ssrc
	)

Sets the SSRC identifier of this transport.

Call before sending any packets. Used when the SSRC must match a value declared in the SDP (e.g., WebRTC a=ssrc lines).

Precondition

self != NULL

datatype99()

datatype99	(	Compy_RtpTimestamp	,
		(Compy_RtpTimestamp_Raw, uint32_t)	,
		(Compy_RtpTimestamp_SysClockUs, uint64_t)
	)

An RTP timestamp.

Variants

• Raw – The value to be assigned to Compy_RtpHeader.timestamp without further conversion.
• SysClockUs – The timestamp value in microseconds derived from a system clock (e.g., clock_gettime). It should be used when a raw timestamp cannot be computed, as typically occurs with real-time video.

See Datatype99 for the macro usage.

declImplExtern99()

declImplExtern99	(	Compy_Droppable	,
		Compy_RtpTransport
	)

Implements Compy_Droppable_IFACE for Compy_RtpTransport.

See Interface99 for the macro usage.