Towards an RTP Profile for IPTV
Marcel Wagner,Ivan Kopilovic,Stefan Dohla,Nikolaus Farber, and Harald Fuchs
in IEEE Transcations
資工碩二 林季謙
Introduction
 Transport protocols for IPTV
 MPEG2-TS
 In Broadcasting world
 RTP
 In Internet and mobile world
MPEG2-TS
MPEG2-TS
RTP
End to End IPTV System Model
RTP IPTV Profile
 Allow parameter identification
 The receiver must be able to reconstruct the receiver
side parameters of the end-to-end system model.
 Allow model verification
 It should be possible to verify the operation of a real
system against the model parameters to control the
encoder operation and to allow monitoring and
testing
 Allow backward compatibility
 The model should extend the existing timing concepts
of RTP. A conventional RTP receiver should be able to
decode and play out these streams
RTP IPTV Profile-Base Profile
 Base Profile
 Focuses on goals 1 and 3.
 Provides means to estimate the required parameters with
minimal changes to the timing concepts of RTP
 Extend Profile
 It can also achieve goal 2 and also provides more explicit
information for parameter identification
Base Profile
 Sender Clock Synchronization
 RTP timestamps
 RTCP transmission interval
Extend Profile
 Buffering delay
 Random access flag
 Time discontinuity flag
 Time refinement field
Conclusion
 RTP provides more flexibility but also imposes more complexity on the
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receiver which in turn leads to less predictable.
In order to reduce the complexity and achieve convergence between RTP and
MPEG2-TS,They defines additional constraints and reduce the flexibility of RTP.
THE Baseline Profile requires synchronized sender clocks and more frequent
RTCP. In addition the RTP timestamp is interpreted. Similar to Mpeg2-TS.If
network jitter become, The Baseline Profile cannot assure model verification
The Extended Profile adds additional information to the RTP packets which
provide the required information in an explicit way.
Based on the proposed profiles it becomes possible to convert between
MPEG2-TS and RTP in a protocol gateway or to combine MPEG2-TS service
with additional RTP streams.