rdt.c File Reference

Realmedia RTSP protocol (RDT) support. More...

#include "avformat.h"
#include "libavutil/avstring.h"
#include "rtpdec.h"
#include "rdt.h"
#include "libavutil/base64.h"
#include "libavutil/md5.h"
#include "rm.h"
#include "internal.h"
#include "avio_internal.h"
#include "libavcodec/get_bits.h"

Classes
struct	RDTDemuxContext
struct	PayloadContext
	RTP/JPEG specific private data. More...

Macros
#define	XOR_TABLE_SIZE   37
#define	RDT_HANDLER(n, s, t)

Functions
RDTDemuxContext *	ff_rdt_parse_open (AVFormatContext *ic, int first_stream_of_set_idx, void *priv_data, const RTPDynamicProtocolHandler *handler)
	Allocate and init the RDT parsing context. More...
void	ff_rdt_parse_close (RDTDemuxContext *s)
void	ff_rdt_calc_response_and_checksum (char response[41], char chksum[9], const char *challenge)
	Calculate the response (RealChallenge2 in the RTSP header) to the challenge (RealChallenge1 in the RTSP header from the Real/Helix server), which is used as some sort of client validation. More...
int	ff_rdt_parse_header (const uint8_t *buf, int len, int *pset_id, int *pseq_no, int *pstream_id, int *pis_keyframe, uint32_t *ptimestamp)
	Actual data handling. More...
int	ff_rdt_parse_packet (RDTDemuxContext *s, AVPacket *pkt, uint8_t **bufptr, int len)
	Parse RDT-style packet data (header + media data). More...
void	ff_rdt_subscribe_rule (char *cmd, int size, int stream_nr, int rule_nr)
	Add subscription information to Subscribe parameter string. More...
void	ff_real_parse_sdp_a_line (AVFormatContext *s, int stream_index, const char *line)
	Parse a server-related SDP line. More...
	RDT_HANDLER (live_video, "x-pn-multirate-realvideo-live", AVMEDIA_TYPE_VIDEO)
	RDT_HANDLER (live_audio, "x-pn-multirate-realaudio-live", AVMEDIA_TYPE_AUDIO)
	RDT_HANDLER (video, "x-pn-realvideo", AVMEDIA_TYPE_VIDEO)
	RDT_HANDLER (audio, "x-pn-realaudio", AVMEDIA_TYPE_AUDIO)

Detailed Description

Realmedia RTSP protocol (RDT) support.

Author

Ronald S. Bultje rbult.nosp@m.je@r.nosp@m.onald.nosp@m..bit.nosp@m.freak.nosp@m..net

Macro Definition Documentation

RDT_HANDLER

#define RDT_HANDLER	(		n,
			s,
			t
	)

Value:

RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
    .enc_name         = s, \
    .codec_type       = t, \
    .codec_id         = AV_CODEC_ID_NONE, \
    .priv_data_size   = sizeof(PayloadContext), \
    .init             = rdt_init, \
    .parse_sdp_a_line = rdt_parse_sdp_line, \
    .close            = rdt_close_context, \
    .parse_packet     = rdt_parse_packet \
}

Function Documentation

ff_rdt_calc_response_and_checksum()

void ff_rdt_calc_response_and_checksum	(	char	response[41],
		char	chksum[9],
		const char *	challenge
	)

Calculate the response (RealChallenge2 in the RTSP header) to the challenge (RealChallenge1 in the RTSP header from the Real/Helix server), which is used as some sort of client validation.

Parameters

response	pointer to response buffer, it should be at least 41 bytes (40 data + 1 zero) bytes long.
chksum	pointer to buffer containing a checksum of the response, it should be at least 9 (8 data + 1 zero) bytes long.
challenge	pointer to the RealChallenge1 value provided by the server.

ff_rdt_parse_header()

int ff_rdt_parse_header	(	const uint8_t *	buf,
		int	len,
		int *	pset_id,
		int *	pseq_no,
		int *	pstream_id,
		int *	pis_keyframe,
		uint32_t *	ptimestamp
	)

Actual data handling.

Parse RDT-style packet header.

return 0 on packet, no more left, 1 on packet, 1 on partial packet...

Layout of the header (in bits): 1: len_included Flag indicating whether this header includes a length field; this can be used to concatenate multiple RDT packets in a single UDP/TCP data frame and is used to precede RDT data by stream status packets 1: need_reliable Flag indicating whether this header includes a "reliable sequence number"; these are apparently sequence numbers of data packets alone. For data packets, this flag is always set, according to the Real documentation [1] 5: set_id ID of a set of streams of identical content, possibly with different codecs or bitrates 1: is_reliable Flag set for certain streams deemed less tolerable for packet loss 16: seq_no Packet sequence number; if >=0xFF00, this is a non-data packet containing stream status info, the second byte indicates the type of status packet (see wireshark docs / source code [2]) if (len_included) { 16: packet_len } else { packet_len = remainder of UDP/TCP frame } 1: is_back_to_back Back-to-Back flag; used for timing, set for one in every 10 packets, according to the Real documentation [1] 1: is_slow_data Slow-data flag; currently unused, according to Real docs [1] 5: stream_id ID of the stream within this particular set of streams 1: is_no_keyframe Non-keyframe flag (unset if packet belongs to a keyframe) 32: timestamp (PTS) if (set_id == 0x1F) { 16: set_id (extended set-of-streams ID; see set_id) } if (need_reliable) { 16: reliable_seq_no Reliable sequence number (see need_reliable) } if (stream_id == 0x3F) { 16: stream_id (extended stream ID; see stream_id) } [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt [2] http://www.wireshark.org/docs/dfref/r/rdt.html and http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c

ff_rdt_parse_open()

RDTDemuxContext* ff_rdt_parse_open	(	AVFormatContext *	ic,
		int	first_stream_of_set_idx,
		void *	priv_data,
		const RTPDynamicProtocolHandler *	handler
	)

Allocate and init the RDT parsing context.

Parameters

ic	the containing RTSP demuxer context
first_stream_of_set_idx	index to the first AVStream in the RTSP demuxer context's ic->streams array that is part of this particular stream's set of streams (with identical content)
priv_data	private data of the payload data handler context
handler	pointer to the parse_packet() payload parsing function

Returns

a newly allocated RDTDemuxContext. Free with ff_rdt_parse_close().

ff_rdt_parse_packet()

int ff_rdt_parse_packet	(	RDTDemuxContext *	s,
		AVPacket *	pkt,
		uint8_t **	buf,
		int	len
	)

Parse RDT-style packet data (header + media data).

Usage similar to rtp_parse_packet().

< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....

ff_rdt_subscribe_rule()

void ff_rdt_subscribe_rule	(	char *	cmd,
		int	size,
		int	stream_nr,
		int	rule_nr
	)

Add subscription information to Subscribe parameter string.

Parameters

cmd	string to write the subscription information into.
size	size of cmd.
stream_nr	stream number.
rule_nr	rule number to conform to.

ff_real_parse_sdp_a_line()

void ff_real_parse_sdp_a_line	(	AVFormatContext *	s,
		int	stream_index,
		const char *	buf
	)

Parse a server-related SDP line.

Parameters

s	the RTSP AVFormatContext
stream_index	the index of the first stream in the set represented by the SDP m= line (in s->streams)
buf	the SDP line