rtp.c File Reference

Functions to handle RTP headers and packets per RFC 3984 with restricted functionality. More...

#include <netinet/in.h>
#include "global.h"
#include "rtp.h"
#include "sei.h"

Include dependency graph for rtp.c:

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Defines
#define	SYMTRACESTRING(s)
Functions
int	ComposeRTPPacket (RTPpacket_t *p)
int	WriteRTPPacket (RTPpacket_t *p, FILE *f)
int	WriteRTPNALU (ImageParameters *p_Img, NALU_t *n)
void	RTPUpdateTimestamp (ImageParameters *p_Img, int tr)
void	OpenRTPFile (ImageParameters *p_Img, char *Filename)
void	CloseRTPFile (ImageParameters *p_Img)

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Detailed Description

Functions to handle RTP headers and packets per RFC 3984 with restricted functionality.

Author:

Stephan Wenger stewe@cs.tu-berlin.de

Definition in file rtp.c.

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Function Documentation

void CloseRTPFile

(

ImageParameters *

p_Img

)

Closes the output file for the RTP packet stream.

Returns:

none. Function terminates the program in case of an error

Definition at line 320 of file rtp.c.

Referenced by terminate_sequence().

int ComposeRTPPacket

(

RTPpacket_t *

p

)

ComposeRTPpacket composes the complete RTP packet using the various structure members of the RTPpacket_t structure.

Returns:

0 in case of success negative error code in case of failure

Parameters

Caller is responsible to allocate enough memory for the generated packet in parameter->packet. Typically a malloc of 12+paylen bytes is sufficient

Side effects

none

Note:

Function contains assert() tests for debug purposes (consistency checks for RTP header fields

Date:

30 September 2001

Author:

Stephan Wenger stewe@cs.tu-berlin.de

Definition at line 60 of file rtp.c.

Referenced by WriteRTPNALU().

void OpenRTPFile	(	ImageParameters *	p_Img,
		char *	Filename
	)

Opens the output file for the RTP packet stream.

Parameters:

	p_Img	Image parameters for current picture encoding
	Filename	The filename of the file to be opened

Returns:

none. Function terminates the program in case of an error

Definition at line 299 of file rtp.c.

Referenced by start_sequence().

void RTPUpdateTimestamp	(	ImageParameters *	p_Img,
		int	tr
	)

RTPUpdateTimestamp: patches the RTP timestamp depending on the TR.

Parameters:

	p_Img	Image parameters for current picture encoding
	tr	tr: TRof the following NALUs

Returns:

none.

This is a violation of the security req. of

RTP (random timestamp), but easier to debug

The following code assumes a wrap around of TR at 256, and needs to be changed as soon as this is no more true.

The support for B frames is a bit tricky, because it is not easy to distinguish between a natural wrap-around of the tr, and the intentional going back of the tr because of a B frame. It is solved here by a heuristic means: It is assumed that B frames are never "older" than 10 tr ticks. Everything higher than 10 is considered a wrap around.

Definition at line 250 of file rtp.c.

References img_par::CurrentRTPTimestamp, and RTP_TR_TIMESTAMP_MULT.

Referenced by start_slice().

int WriteRTPNALU	(	ImageParameters *	p_Img,
		NALU_t *	n
	)

int RTPWriteNALU write a NALU to the RTP file

Returns:

Number of bytes written to output file

Side effects

Packet written, RTPSequenceNumber and RTPTimestamp updated

Date:

December 13, 2002

Author:

Stephan Wenger stewe@cs.tu-berlin.de

For error resilience work, we need the correct marker bit. Introduce a nalu->marker and set it in terminate_slice()?

Definition at line 173 of file rtp.c.

References nalu_t::buf, ComposeRTPPacket(), img_par::CurrentRTPSequenceNumber, img_par::CurrentRTPTimestamp, nalu_t::forbidden_bit, H264PAYLOADTYPE, H264SSRC, nalu_t::len, MAXRTPPACKETSIZE, nalu_t::nal_reference_idc, nalu_t::nal_unit_type, no_mem_exit(), nalu_t::startcodeprefix_len, and WriteRTPPacket().

Referenced by start_sequence().

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int WriteRTPPacket	(	RTPpacket_t *	p,
		FILE *	f
	)

WriteRTPPacket writes the supplied RTP packet to the output file.

Returns:

0 in case of access <0 in case of write failure (typically fatal)

Parameters:

	p	the RTP packet to be written (after ComposeRTPPacket() )
	f	output file

Date:

October 23, 2001

Author:

Stephan Wenger stewe@cs.tu-berlin.de

Definition at line 131 of file rtp.c.

Referenced by WriteRTPNALU().