Packetizing scalable streams in heterogeneous peer-to-peer networks<br />Sentinelli, A. Kumar, T. Anselmo, B. Rossi, L. Fr...
AGENDA<br />Introduction<br />Industrial Scenario<br />The idea in a nutshell<br />Background<br />SVCand P2P together<br ...
Scenario: delivery to different networks<br />The <br />Internet<br />IPTV Set-Top Box<br />Media<br />Server<br />Same<br...
Background: P2P-Next project<br />101010100010110110010<br />Application Layer: Layered Video Coding(SVC, MDC, others…)<br...
The idea in a nutshell<br />P2P-Next EU project. Integration’s challenge :<br />Big picture view;<br />Interface designs a...
Interface between the P2P and the Layered Video Coding engine<br />The server delivers two different streams independently...
Background: P2P – Next, full system<br />Wefound a “problem”<br />We focused<br /><br /><ul><li>Backward compatibility wit...
IDR synchronization among NALU of different layers</li></li></ul><li>8<br />From NALU toBlocks: overhead<br />The Splitter...
From NALU toBlocks: framesskipped<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NA...
P2P-Next Splitter: packetization trade -off<br />Oneblock per IDR, withNfr (Number of Frames per block)<br />What is the b...
P2P-Next Splittervs AdaptiveSplitter<br />P2P-Next approach: a unique block to embrace an IDR period<br />Adaptive Splitte...
Adaptive Splitter: Adaptive blocks Mapping<br />EL 2,1 block<br />EL 2,2 block<br />EL 2,3 block<br />EL 2,4 block<br />EL...
Experiments and results<br />Theoreticalmodel:<br />When the overhead decreases, the IDR size gets close to a multiple of ...
Experiments and results<br />The best Bs isnotalways the smallestone:<br />MyBs<br />
Experiments and results<br />Experiments on 6 sequences (5 short ones+ 1 HD)<br />On the whole, the adaptive approach give...
Conclusions<br />We have described the architecture of a P2P-SVC solution and the issues that overcome during the integrat...
THANK YOU !<br />
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Packetizing scalable streams in heterogeneous peer to-peer networks

  1. 1. Packetizing scalable streams in heterogeneous peer-to-peer networks<br />Sentinelli, A. Kumar, T. Anselmo, B. Rossi, L. Fragneto<br />STMicroelectronics<br />Advanced System Technology (AST)<br />Agrate Brianza (MB), Italy<br />ICME 2011Barcelona<br />
  2. 2. AGENDA<br />Introduction<br />Industrial Scenario<br />The idea in a nutshell<br />Background<br />SVCand P2P together<br />P2P Next <br />Splitter<br />Issues<br />P2P-Next solution<br />(propose solution) Adaptive Splitter<br />Experiments and results<br />Conclusions<br />
  3. 3. Scenario: delivery to different networks<br />The <br />Internet<br />IPTV Set-Top Box<br />Media<br />Server<br />Same<br />Scalable Video<br />SVC can offer easy adaptation to:<br />Desired QoS<br />Bandwidth conditions<br />Terminal capabilities<br />Just “cut” portionsof the stream (No additionalcost)<br />Hierarchicalcoding (Just take the layersthat I need)<br />Onecontentstreamat server side (lessstorage)<br />
  4. 4. Background: P2P-Next project<br />101010100010110110010<br />Application Layer: Layered Video Coding(SVC, MDC, others…)<br />Network Layer : P2P (File-Sharing, Streaming)<br />Networkscalability<br />Videoqualityscalability<br />GOAL: <br />To combine P2Pand Layered Video Coding<br />
  5. 5. The idea in a nutshell<br />P2P-Next EU project. Integration’s challenge :<br />Big picture view;<br />Interface designs among modules/layers/protocols;<br />Backward compatibility;<br />High chance of bottleneck or general loss of efficiency (overhead)<br />We found a strong lack of performance in the module that packetizes the Video stream into a P2P packet<br />Wecompare twotypesof packetization methods<br />
  6. 6. Interface between the P2P and the Layered Video Coding engine<br />The server delivers two different streams independently encodedStream S1 = Low QualityStream S2 = High Quality<br />The server delivers two layers (Base + Enhancement):Stream S1 = Base LayerStream S2 = Base + Enh Layer<br />Base Layer<br />Enh Layer<br />S1<br />Base + Enh Layer<br />S2<br />S1<br />Main server<br />S2<br />Main server<br />Background: P2P - synergy with SVC<br />OLD: Overlays can NOT cooperate<br />NEW: Overlays able to cooperate<br />NAT and P2P v.1<br />
  7. 7. Background: P2P – Next, full system<br />Wefound a “problem”<br />We focused<br /><br /><ul><li>Backward compatibility with P2P systems
  8. 8. IDR synchronization among NALU of different layers</li></li></ul><li>8<br />From NALU toBlocks: overhead<br />The Splitter parses and puts NALUs to respective layers<br />Re-encapsulates the streamintoBlocksfor the P2P engine<br />CONSTRAINT: backwardcompatibilitywithtorrent-likesystem<br />ALL blocksmusthave the samesize ( NALU type 12 *)<br /> *(stuffingbits)<br />Overhead<br />
  9. 9. From NALU toBlocks: framesskipped<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />BL CHUNK<br />BL CHUNK<br />BL CHUNK<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />BL NALU<br />EL1 CHUNK<br />EL1 CHUNK<br />EL1 CHUNK<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL1 NALU<br />EL2 CHUNK<br />EL2 CHUNK<br />EL2 CHUNK<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />EL2 NALU<br />Video Encoder<br />Input<br />Pictures<br />RAP PictureNALUs<br />Non-RAP PictureNALUs<br />Encapsulation<br />Peer-to-Peer<br />Engine<br />LAYERS MUST BE KEPT SYNCHRONIZED<br />All Blocks must have the same number of frames<br />When a NALU doesn't fit into the block it is simply dropped<br />
  10. 10. P2P-Next Splitter: packetization trade -off<br />Oneblock per IDR, withNfr (Number of Frames per block)<br />What is the best [Bs, Nfr] ? (Bs : Block size)<br />(trade off)Keep all framesvsLess Overhead<br />%frame skipped<br />BlockSize<br />Num Frames<br />On avg, given a bitrate B, the optimal trade off is when : Bs =Nfr· AvgFrB<br />AvgFrB: average size of a Frame given a bitrate B<br />
  11. 11. P2P-Next Splittervs AdaptiveSplitter<br />P2P-Next approach: a unique block to embrace an IDR period<br />Adaptive Splitter: many smaller (same size) blocks to cover until needed an IDR period (a black scene has less information than a panorama)<br />The Adaptive Splitter never discards frames<br />
  12. 12. Adaptive Splitter: Adaptive blocks Mapping<br />EL 2,1 block<br />EL 2,2 block<br />EL 2,3 block<br />EL 2,4 block<br />EL1,1 block<br />EL 1,2 block<br />EL 1,3 block<br />BL 0,1 block<br />BL 0,2 block<br />(...)<br />(2,3,4)<br />BL 0,1<br />BL 0,2<br />EL1,1<br />EL 1,2<br />EL 1,3<br />EL 2,1<br />EL 2,2<br />EL 2,3<br />EL 2,4<br />(2,2,2)<br />BL 0,1<br />BL 0,2<br />EL1,1<br />EL 1,2<br />EL 2,1<br />EL 2,2<br />Quality<br />Block Mask IDRi<br />#blocks EL2<br />#blocks EL1<br />#blocks BL<br />time<br />Final Stream<br />IDRi<br />IDRi+1<br />Headers to identify the blocks Mask (blocks per IDR per Layer )<br />#blocks per IDR isdependentbyeach IDR size<br />“So…whynotchoosing a block ofone 1 byte?”<br />Toomuchsignalingoverhead…<br />Becauseof the backwardcompatibility: (BitTorrent) MIN size=16kB<br />
  13. 13. Experiments and results<br />Theoreticalmodel:<br />When the overhead decreases, the IDR size gets close to a multiple of Bs<br />
  14. 14. Experiments and results<br />The best Bs isnotalways the smallestone:<br />MyBs<br />
  15. 15. Experiments and results<br />Experiments on 6 sequences (5 short ones+ 1 HD)<br />On the whole, the adaptive approach gives up to:<br /> ≈77% decrease in overhead, <br />≈16% less of bandwidth<br />
  16. 16. Conclusions<br />We have described the architecture of a P2P-SVC solution and the issues that overcome during the integration<br />Performance comparison in terms of overhead of between the P2P-Next and the Adaptive Splitter<br />Results show a remarkable gain (16% bandwidth), confirmed by our mathematical model<br />The Adaptive Splitterdoesn’t require a priori knowledge of block size to preserve all frames: good candidate for live streaming scenario<br />
  17. 17. THANK YOU !<br />
  18. 18. 18<br />Packetizing: overhead<br />Fromrawstreamto 4 SVC encodedlayerswithbitrateB(*) and the mask (1, 1, 1, 3).  ie. the 4° layeris 4B<br />(*) For rate control reasons, each file may have NALU with nal_unit_type = 12. These are Filler Data NALU, required by some application to get a precise { #Bytes/Chunk } and finally discarded by decoder.<br />Overhead<br />

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