rtp.h File Reference

Definition of structures and functions to handle RTP headers. For a description of RTP see RFC1889 on http://www.ietf.org. More...

#include "nalu.h"

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Data Structures
struct	RTPpacket_t
Defines
#define	MAXRTPPAYLOADLEN   (65536 - 40)
#define	MAXRTPPACKETSIZE   (65536 - 28)
#define	H264PAYLOADTYPE   105
#define	H264SSRC   0x12345678
#define	RTP_TR_TIMESTAMP_MULT   1000
Functions
void	RTPUpdateTimestamp (ImageParameters *p_Img, int tr)
void	OpenRTPFile (ImageParameters *p_Img, char *Filename)
void	CloseRTPFile (ImageParameters *p_Img)
int	WriteRTPNALU (ImageParameters *p_Img, NALU_t *n)

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Detailed Description

Definition of structures and functions to handle RTP headers. For a description of RTP see RFC1889 on http://www.ietf.org.

Date:

30 September 2001

Author:

Stephan Wenger stewe@cs.tu-berlin.de

Definition in file rtp.h.

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Define Documentation

#define H264PAYLOADTYPE   105

RTP paylaod type fixed here for simplicity.

Definition at line 25 of file rtp.h.

Referenced by WriteRTPNALU().

#define H264SSRC   0x12345678

SSRC, chosen to simplify debugging.

Definition at line 26 of file rtp.h.

Referenced by WriteRTPNALU().

#define MAXRTPPACKETSIZE   (65536 - 28)

Maximum size of an RTP packet incl. header.

Definition at line 24 of file rtp.h.

Referenced by WriteRTPNALU().

#define MAXRTPPAYLOADLEN   (65536 - 40)

Maximum payload size of an RTP packet.

Definition at line 23 of file rtp.h.

Referenced by clear_sei_message(), ClearSubseqInfoPayload(), FinalizeSpareMBMap(), InitSparePicture(), and InitSubseqInfo().

#define RTP_TR_TIMESTAMP_MULT   1000

should be something like 27 Mhz / 29.97 Hz

Definition at line 27 of file rtp.h.

Referenced by RTPUpdateTimestamp().

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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().

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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