rtp taxonomy & relationships

1

RTP Taxonomy &

Relationships

@Authors

draft-lennox-raiarea-rtp-grouping-taxonomy-03IETF 88

Changes Since -02

• Major re-write– Section 2, Concepts, re-structured to a conceptual

media chain with Streams and Transformations– Section 3, Relations, re-organized and added

descriptions of a few more functional relations– Section 4, Communication Entities, aligned

taxonomy with Section 2

Way Forward

• Is the draft ready enough for WG adoption?

Media Streams and TransformationsThe flow of media signal undergoes a series of transformations from the source to the sink

Transformations: Encoder,Decoder, …

Media Streams: Encoded Stream, Source Stream, …

Media Streams and Transformations o A transformation may have zero or more input Streams and one or more output Streams.

o A Stream is of some type.

o A Stream has one source transformation and one or more sink transformations.

o Streams can be forwarded from a transformation output to any number of inputs on other transformations that support that type.

o If the output of a transformation is sent to multiple transformations, those streams will be identical; it takes a transformation to make them different.

o There are no formal limitations on how streams are connected to transformations, this may include loops if required by a particular transformation.

Audio, Video with 2 simulcast streams w/repair stream - (Sender Side)

Media Transport(2)

Physical Stimulus

Media Capture(Audio)

Media Source(Audio)

Media Transport (1)

Media Source(Video)

Media Packetizer

(Simulcast 1)

Media Capture(Video)

Media Encoder(Simulcast 2)


Media Encoder(Audio)

Media Packetizer

(Audio)

Media Packetizer

(Simulcast 2)

Media Redundancy

(Simulcast 2 R)

Media Transport (2)

Media Redundancy

(Simulcast 1 R)

Media Transport(2)

Raw Stream



Media Source(Audio)

Media Transport (1)

Media Source(Video)

Media Packetizer

(Simulcast 1)





Media Packetizer

(Audio)

Media Packetizer

(Simulcast 2)

Media Redundancy

(Simulcast 2 R)

Media Transport (2)

Media Redundancy

(Simulcast 1 R)

Media Transport(2)

Source Stream



Media Source(Audio)

Media Transport (1)

Media Source(Video)

Media Packetizer

(Simulcast 1)





Media Packetizer

(Audio)

Media Packetizer

(Simulcast 2)

Media Redundancy

(Simulcast 2 R)

Media Transport (2)

Media Redundancy

(Simulcast 1 R)

Media Transport(2)



Media Source(Audio)

Media Transport (1)

Media Source(Video)

Media Packetizer

(Simulcast 1)





Media Packetizer

(Audio)

Media Packetizer

(Simulcast 2)

Media Redundancy

(Simulcast 2 R)

Media Transport (2)

Media Redundancy

(Simulcast 1 R)

Encoded Stream

Media Transport(2)



Media Source(Audio)

Media Transport (1)

Media Source(Video)

Media Packetizer

(Simulcast 1)





Media Packetizer

(Audio)

Media Packetizer

(Simulcast 2)

Media Redundancy

(Simulcast 2 R)

Media Transport (2)

Media Redundancy

(Simulcast 1 R)

Source Packet Stream


Media Source(Audio)

Media Transport (1)

Media Source(Video)

Media Packetizer

(Simulcast 1)





Media Packetizer

(Audio)

Media Packetizer

(Simulcast 2)

Media Redundancy

(Simulcast 2 R)

Media Transport (2)

Media Redundancy

(Simulcast 1 R)


Redundancy Packet Stream

Received Packet Stream,Received Redundancy Packet

Stream

Media Sink(Audio)

Media Transport (1)

Media Depacketizer(Simulcast 1)

Media Decoder(Simulcast 2)


Media Decoder(Audio)

Media Depacketizer

(Audio)

Media DePacketizer(Simulcast 2)

Media Transport (2)

Media Repair

Media Sink(Simulcast 1)


Audio, Video with 2 simulcast streams w/repair stream - (Recv Side)

Media Renderer(Simulcast 2)


Media Renderer(Audio)

Repaired Packet Stream


Media Sink(Audio)

Media Transport (1)





Media Depacketizer

(Audio)


Media Transport (2)

Media Repair






Received Encoded Stream


Media Sink(Audio)

Media Transport (1)





Media Depacketizer

(Audio)


Media Transport (2)

Media Repair






Received Source Stream


Media Sink(Audio)

Media Transport (1)





Media Depacketizer

(Audio)


Media Transport (2)

Media Repair






Received Raw Stream


Media Sink(Audio)

Media Transport (1)





Media Depacketizer

(Audio)


Media Transport (2)

Media Repair






Media Transport Sender

Received Packet Stream

Media Transport Receiver

Network Transport

Transported Packet Stream

Sent Packet Stream

Packet Stream

Media Transport Detailed

Communication Entities

End Point

RTP Session

A single addressable entity sending or receiving RTP packets. It may be decomposed into several functional blocks, but as long as it behaves as a single RTP stack entity it is classified as a single "End Point".

An association among a group of participants communicating with RTP. It is a group communications channel which can potentially carry a number of Packet Streams. Within an RTP Session, every participant can find meta-data and control information (over RTCP) about all the Packet Streams in the RTP session.

Participant

Multimedia Session

An entity reachable by a single signaling address,and is thus related more to the signaling context than to the mediacontext. A Participant can have multiple Multimedia Sessions.

An association among a group of participants engaged in the communication via one or more RTP Sessions. It defines logical relationships among Media Sources that appear in multiple RTP Sessions.

A Multimedia Session can be composed of several parallel RTP Sessions with potentially multiple Packet Streams per RTP Session.

Communication SessionAn association among group of Participants communicating with each other via a set of Multimedia Sessions.

Each Participant in a Communication Session is identified via an application specific signaling address.

A Communication Session is composed of at least one Multimedia Session per Participant, involving one or more parallel RTP Sessions with potentially multiple Packet Streams per RTP Session.

Concept Relations

Relations at Different Levels

• The reason why a relation is needed on one level may be functionality on a different level– E.g. Simulcast relate Packet Streams to identify a

common Media Source• Briefly describes a set of existing functional relations

in taxonomy terms– Synchronization– Simulcast– Layered encoding– Robustness and repair

Topologies and Communication Entities

Point-to-Point Communication

Participant A

EndPoint A

Participant B

EndPoint B

RTP AudioSession

RTP VideoSession

Media Transport

Media Transport

Multimedia Session(SIP Dialog)

Communication Session

Remaining Issues

• To what extent should terminology used in existing RTP-related RFCs be clarified and mapped onto the proposed taxonomy by the draft?

• Are there more functionalities involving Stream relations that should be described?

• To what extent should Stream relation and identification needs from different RTP Topologies be elaborated?

• More?

Thank You

rtp taxonomy & relationships

Documents

media streams

media redundancysimulcast

r media transport2audio

conceptual media chain

o streams

output streams

input streams

rmedia transport