Limiting the client bandwidth of broadcasting protocols for video on demand Jehan-Francois Paris and Darrell D.E. Long Proceedings of the Euromedia 2000 Conference

Outline Previous Schemes Previous Schemes Skyscraper broadcasting Skyscraper broadcasting Fast data broadcasting Fast data broadcasting Pagoda broadcasting Pagoda broadcasting Approach in this paper (improving FB and Pagoda) Approach in this paper (improving FB and Pagoda) Result and my experiment Result and my experiment Conclusion Conclusion

Patching 1998, 53 Batching 1994, 154 Skyscraper 1997, 101 PPB 1996, 61 Harmonic 1997, 34 Stream Tapping 1997, 27 Piggyback 1996, 20 Fast Data Broadcast 1996, 19 Pyramid 1995, 19 DSB 1998, 25 Pagoda 1999, 4 New Pagoda 1999, 4 CHB, QHB 1998, 12 PHB 1998, 17 Staggered Broadcasting Universal Distribution 2000 HMSM 2001 SAM(VCR) 1997 Seamless Channel Transition (FB) 2001 Adaptive Fast Data Broadcasting 2001 … Adding VCR … Current Paper Low I/O Bandwidth

Objective Bandwidth (delay time) Bandwidth (delay time) Ex: FB -> Pagoda -> New Pagoda Storage Storage Ex: PB -> PPB Scalable (wide range) Scalable (wide range) Ex: Ex: FB -> UD VCR Functionality VCR Functionality Ex: Staggered Broadcast -> SAM Channel Adjustment Channel Adjustment Ex: FB -> Seamless Channel Transition I/O BANDWIDTH Ex: FB -> SB, current paper

Skyscraper Broadcasts Constraint Constraint For any initial unit segment broadcast, there must be a sequence of segments that the client can receive that will support continuous playback to the viewer For any initial unit segment broadcast, there must be a sequence of segments that the client can receive that will support continuous playback to the viewer Clients are required to receive data on no more than two channels simultaneously Clients are required to receive data on no more than two channels simultaneously

Skyscraper Broadcasts Progression Progression we use W to restrict the segments from becoming too large. we use W to restrict the segments from becoming too large. EX ： W= 12 EX ： W= 12 [ 1, 2, 2, 5, 5, 12, 12, 12, 12 … ] [ 1, 2, 2, 5, 5, 12, 12, 12, 12 … ]

Transmitting and Receiving of Segments (SB) Channel 1 Channel 2 Channel 3 Playback Channel 4 Channel 5

Fast data broadcasting Allocates to each video to be broadcast k data channels whose bandwidths are equal to the video consumption rate b Partitions the video into 2 k-1 segments S 1 to S 2 k-1 of equal duration d The channel i broadcasts S 2 i-1 to S 2 i -1

Transmitting and Receiving of Segments (FB) Channel Channel 2 23 Channel

New Pagoda broadcasting Using a more complex segment-to-channel mapping The NPB protocol can pack nine segments into three channels whereas the FB protocol could only pack seven segments S i means S i must be broadcasted once every i slots FB ： S 7 is broadcasted once every 4 slots New Pagoda ： S 7 is broadcasted once every 6 slots

Transmitting and Receiving of Segments (NPB) Channel Channel 2 24 Channel

Approach in the paper Allow to receive data from the first m of these k channels. Allow to receive data from the first m of these k channels. Downloading data from the k-m remaining channels will be progressively allowed as STB starts dropping some of the first m channels. Downloading data from the k-m remaining channels will be progressively allowed as STB starts dropping some of the first m channels. The STB will start receiving data from channel m + 1 when it is finished with the first channel.

Approach in the paper The segments in the first m channels The segments in the first m channels Segment S i repeated at least once every i slots Segment S i repeated at least once every i slots The segments in the remaining (k – m) channels The segments in the remaining (k – m) channels After slots n k-m, the channel k-m can be downloaded data. After slots n k-m, the channel k-m can be downloaded data. Segment S i repeated at least once every (i - n k-m ) slots Segment S i repeated at least once every (i - n k-m ) slots

In Fast broadcasting (FB-3) 8-1=7 15-2= = =44

In Fast broadcasting (FB-4)

In NPB (NPB-3)

Channel 4 (NPB-3) a) segments S 10 to S 12 once every 9 slots b) segments S 13 to S 16 once every 12 slots c) segments S 17 to S 21 once every 15 slots

Channel 5 (NPB-3) a) segments S 22 to S 27 once every 18 slots b) segments S 28 to S 35 once every 24 slots c) segments S 36 to S 40 once every 30 slots d) segments S 41 to S 46 once every 36 slots

In NPB (NPB-4)

Result 1

Result 2

My Experiment 1 Chann el FB-2 Skyscrap er FB

My Experiment 2 (FB-2) Channel Delay (slots) Segments number of segments Total number of segments number of buffer Buffer / total 10S11100% 20S2 ~ S323133% 31S4 ~ S636233% 42S7 ~ S % 54S12 ~ S % 67S20 ~ S % 712S33 ~ S %

My Experiment 3 FB-2FB-3FB-4FB bufferbuffer/totalbufferbuffer/totalbufferbuffer/totalbufferbuffer/total Original 1238%2345%3153%3149% Ours 825%1529%1831%1625% Total

Conclusion We have shown how to modify existing broadcasting protocols so that their client bandwidth would never exceed three to four channels. Most broadcasting protocols require a customer set-top box capable of simultaneously capturing data from five to eight video channels.