Mod4_VideoDelivery - Scalable Video Delivery Techniques...

Info iconThis preview shows pages 1–16. Sign up to view the full content.

View Full Document Right Arrow Icon
Scalable Video Delivery Techniques Kien A. Hua Data Systems Lab School of EECS University of Central Florida
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
TEST #1 2 8 6 1 60s 70s 80s 90s Score #Students Keep up the good work
Background image of page 2
Server Channels The unit of server capacity required to deliver a video stream is referred to as a channel . These channels are dispatched to deliver various video streams at different times.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Using Dedicated Streams Video Server Dedicated stream Expensive & not scalable Client Waitin g Client Client Client Out of bandwidt h
Background image of page 4
A Solution Using broadcast to share channels among users Broadcast is essentially “free” for a large user community
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Traditional Multicast Video Server Client Client Client Client
Background image of page 6
Conflicting Goals in Video Multicast ? Low Latency : requests must be served as soon as possible High Efficiency : each multicast should wait to serve a larger number of clients Can we achieve both ?
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Broadcast for VOD Requirement on server bandwidth is independent of the number of users the system is designed to support. Less expensive & more scalable !! Broadcast cannot deliver videos on demand ? True False ? ?
Background image of page 8
Simple Periodic Broadcast Staggered Broadcasting Time W Channel 1 Channel 4 L video i video i video i video i video i video i video i video i video j video j Channel 5 video j video j video j video j Channel 7 W=L/N where N is the number of channels W=L/4 9 A new stream is started every interval for each video. The worst service latency is the broadcast period.
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Limitation of Simple Periodic Broadcast Access latency can be improved only linearly with increases to the server bandwidth Double the number of channels to reduce the service latency in half Can we do better ?
Background image of page 10
Odd group Even group Odd group Even group Skyscraper Broadcasting Each video is fragmented into K segments, each repeatedly broadcast on a dedicated channel at the playback rate . The sizes of the K segments have the following pattern: [1, 2, 2, 5, 5, 12, 12, 25, 25, …, W, W, …, W] Size of larger segments are constrained to W (width of the “skyscraper”)
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Generating Function The broadcast series is generated using the following recursive function: 1 If n = 1, 2 If n = 2 or 3, 2 · f ( n - 1)+1 If n mod 4 = 0. f ( n -1) If n mod 4 = 1, 2 · f ( n - 1) + 2 If n mod 4 = 2, f(n) =
Background image of page 12
Skyscraper Broadcasting Playback Procedure Buffer Odd Loader Even Loader Video Player Broadcast Channels 13 The Odd Loader and the Even Loader download the odd groups and the even groups, respectively. W -segments are downloaded sequentially using only one loader. As the loaders fill the buffer, the Video Player consumes the data in the buffer.
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Skyscraper Broadcasting Playback Procedure time 14 Each segment is available before it is needed for the playback 1 2 3 4 5 6 7 8 Playback schedule:
Background image of page 14
Advantages of Skyscraper Broadcasting Unlimited scalability Service latency can be reduced exponentially with increases in server bandwidth Since W-segments are downloaded sequentially, buffer requirement is minimal .
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 16
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 137

Mod4_VideoDelivery - Scalable Video Delivery Techniques...

This preview shows document pages 1 - 16. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online