media synchronization draft-brandenburg-avt-rtcp-for-idms-04 - - PowerPoint PPT Presentation

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media synchronization draft-brandenburg-avt-rtcp-for-idms-04 - - PowerPoint PPT Presentation

RTCP for inter-destination media synchronization draft-brandenburg-avt-rtcp-for-idms-04 draft-brandenburg-avtcore-rtcp-for-idms-00 Ray van Brandenburg, TNO Hans Stokking, TNO Oskar van Deventer, TNO Ishan Vaishnavi, CWI Fernando Boronot,


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SLIDE 1

RTCP for inter-destination media synchronization

draft-brandenburg-avt-rtcp-for-idms-04 draft-brandenburg-avtcore-rtcp-for-idms-00

Ray van Brandenburg, TNO Hans Stokking, TNO Oskar van Deventer, TNO Ishan Vaishnavi, CWI Fernando Boronot, Universidad Politecnica de Valencia Mario Montagud, Universidad Politecnica de Valencia

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SLIDE 2

Recap: the problem solved by IDMS

To synchronize two or more geographically distributed RTP receivers

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SLIDE 3

Current status of draft

  • At IETF79 and on mailing list, two main issues were

raised:

– Use of RTCP XR for server->client messaging – Issues regarding the use of NTP

  • New version (avt-04/avtcore-00) attempts to solve these

issues

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SLIDE 4

Issue – Use of RTCP-XR for server->client

  • Draft presented at IETF 79 used the same RTCP XR block for

client->server and server->client messages

– Flag to identify nature of message

  • Issue: Server->client message tells clients when they should play-
  • ut particular RTP packets

– Basically control information – Therefore not suited for RTCP XR

  • New version introduces new RTCP packet type for server->client

message

– Content of message remains the same – Client->server message uses existing XR block

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SLIDE 5

Issue – Use of RTCP-XR for server->client - 2

Multimedia Source

Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Receiver 1 Receiver 2 Receiver n . . .

RTCP XR IDMS block RTCP IDMS Packet Type

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SLIDE 6

Issue - Use of NTP

  • Draft presented at IETF 79 assumed ‘NTP synchronization’ between

clients

  • Two main issues:

– Time difference between different NTP servers – Is NTP itself accurate enough for all applications of IDMS?

  • Solution - new SDP parameter to describe:

– Type of time source used: NTP, GPS, Gallileo, PTP, etc. – In case of NTP: the used NTP server

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SLIDE 7

Summary

  • Changes in draft since IETF 79:

– New RTCP packet type for server->messaging (incl. SDP parameter) – New SDP parameter for describing used time source – Added additional use cases apart from SocialTV – Added (informative) section with example/overview of IDMS operation – Added (informative) section on timing considerations (when to use which timing source) – Clarified some terminology – Numerous small improvements

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SLIDE 8

Next step

  • Are the presented solutions acceptable?
  • Accept as WG document?
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SLIDE 9

Extra slides: potential new topic on initial synchronization - 1

Source M

. . . Multimedia Source

RTCP XR Receiver Reference Time Report Block

Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Receiver 1 Receiver 2 Receiver n . . .

Allows all receivers to initiate the playout of the media stream at the same time

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SLIDE 10

Extra slides: potential new topic on initial synchronization - 2

Source M

. . . Multimedia Source Maximum/Minimun Network Delay estimation

Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Receiver 1 Receiver 2 Receiver n . . .

RTCP XR DLRR Report Block

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SLIDE 11

Extra slides: potential new topic on initial synchronization - 3

Source M

. . . Multimedia Source This guarantees that all the receivers initiate the playout of the media stream at the same time Initial Playout Instant

Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Agent RTP Agent RTCP Receiver 1 Receiver 2 Receiver n . . .

RTCP IDMS