Transcript RTP Overview Suman Sharma [email protected] 2/22/08 IEEE 1733 Face-to-Face Sandy, Utah RTP Stack SDP Payload Formats RTP RTSP UDP TCP IP RTP: rfc3550 RTSP: rfc2326 SDP: rfc2327 SRTP: rfc3711 RTP/AVP: rfc3551 2/22/08 IEEE 1733 Face-to-Face Sandy, Utah.

RTP Overview
Suman Sharma
[email protected]
2/22/08
IEEE 1733 Face-to-Face
Sandy, Utah
1
RTP Stack
SDP
Payload Formats
RTP
RTSP
UDP
TCP
IP
RTP: rfc3550
RTSP: rfc2326
SDP: rfc2327
SRTP: rfc3711
RTP/AVP: rfc3551
2/22/08
IEEE 1733 Face-to-Face
Sandy, Utah
2
RTP Payload
RTP Header
Payload
2/22/08
IEEE 1733 Face-to-Face
Sandy, Utah
Architecture for Media Streaming
RTSP/SDP
SENDER
(Streaming
Server)
ISMA
RECEIVER
RTP/MPEG
Control Plane
Data Plane
2/22/08
Delivery
IEEE 1733 Face-to-Face
Sandy, Utah
RTP / RTCP Walk-thru
Server
RTP
MP4
File
Client
UDP
RTP
System
Packet
PARSER
READING
DECODER
RESPONSE
PARSER
RTCP
RTCP
SERVER
CLIENT
RTCP
PARSER
RTCP
Out-of-band Control for QoS Reporting
2/22/08
Delivery
IEEE 1733 Face-to-Face
Sandy, Utah
RESPONSE
Mapping of Media Data
Case 1:
Mapping of AU into RTP Packet
Video AU
Case 2:
RTP Header
AU data
Mapping of Video AU into multiple RTP Packets
1/n AU
RTP Header
AU data
RTP Header
AU data
…
…
1/n AU
…
Mapping of Audio AUs into RTP Packet
AU1
AU2
AU3
AU…
RTP payload
RTP
Header
AU1
Header
AU2
Header
AU…
Header
AU header section
2/22/08
Hinting
AU3
Header
IEEE 1733 Face-to-Face
Sandy, Utah
AU = Access Unit
AU data
AU data
AU data AU…
data
RTCP Packet Structure
• RTCP Packet Types
–
–
–
–
–
Sender Report (SR): transmission statistics
Receiver Report (RR): reception statistics
Source Description Item (SDES): CNAME, etc
BYE: end of participation
Application Specific Functions (APP)
• RTCP Compound Packet
– Because RTCP packets are small, one UDP packet
may contain several RTCP packets.
For example, SR + SDES + APP
2/22/08
Delivery
IEEE 1733 Face-to-Face
Sandy, Utah
RTSP Commands
Method
Direction
Requirement
DESCRIBE
Client->Server
Recommended
ANNOUNCE
Client<->Server Optional
GET_PARAMETER
Client<->Server Optional
OPTIONS
Client<->Server Required (S->C: optional)
PAUSE
Client->Server
Recommended
PLAY
Client->Server
Required
RECORD
Client->Server
Optional
REDIRECT
Server->Client
Optional
SETUP
Client->Server
Required
SET_PARAMETER
Client<->Server Optional
TEARDOWN
Client->Server
2/22/08
Delivery
Required
IEEE 1733 Face-to-Face
Sandy, Utah
SDP
• SDP is relevant to the media announcement
• SDP is sent by server in a response to client’s
RTSP:DESCRIBE command request
• Example (video specific lines, SDP sample syntax)
–
–
–
–
–
m=video 0 RTP/AVP 97
a=rtpmap: 97 MP4V-ES
a=control: trackID = 6
a=fmtp: 97 profile-level-id=1
Initial Object Descriptor
config=000001B001000001B5090000010000000120008440FA2
82C2090A21F
– Config includes: AU size; AU index/AU index delta: CTS flag;
CTS delta; DTS flag; DTＳdelta．
– a=mpeg4-esid:201
2/22/08
Delivery
IEEE 1733 Face-to-Face
Sandy, Utah
RTSP / SDP Walk-thru
Client: parse requests and set responses
DESCRIBE
SETUP
Sequential
Stages
Delivery
PLAY
PAUSE
TEARDOWN
NETWORK
OK
2/22/08
SETUP
OK
Read SDP Server:
from MP4 file
OK
OK
OK
OK
parse responses and set requests
IEEE 1733 Face-to-Face
Sandy, Utah
Port Assignment (Example)
RTCP
Port 6981
(Video)
RTP
Port 6980
RTP
Port 6982
RTCP
Port 6981
RTCP
Port 6983
(Audio)
Darwin
Streaming
RTSP
Server
Port 554
or 7070
RTSP
Port 554
or 7070
HTTP
Port 1220
2/22/08
Delivery
QuickTime
Player
Remote-Management
via Web Browser
IEEE 1733 Face-to-Face
Sandy, Utah