HTTP-based Video Streaming Confused, Timid, and Unstable: Picking a Video Streaming Rate is Hard Te-Yuan Huang, Nikhil Handigol, Brandon Heller, Nick McKeown, Ramesh Johari Experimental Setup The Internet Video Client The Internet Bandwidth Controller CDN 1 CDN 2 CDN 3 Content Distribu9on Networks CDN A Get File 1 (1750kb/s), Chunk 1 Serve the video with quality 1750kb/s Playout Buffer Standardized, commoditized HTTP servers Videos are pre-encoded and deployed in CDNs Rate selection logic resides at the client side File 1: File 2: 1750 1750 1050 1050 Problem 0 100 200 300 400 500 600 700 800 900 Time (s) 235 375 560 750 1050 1400 1750 2500 3000 4000 5000 kb/s Available Video Rate Video Flow Throughput Competing Flow Throughput Video Rate Fair Share In the presence of a completing ﬂow, video quality steps down all the way to the lowest Why? Here is the answer! Download and Measure Pick a Rate Initial Bitrate Bandwidth Estimation Video Rate for the Next Chunk Bandwidth Under-estimation: The ON-OFF trafﬁc pattern periodically resets TCP congestion window. Pick a Rate Conservatively: Since the estimated bandwidth typically is not equal to the actual bandwidth, video clients tend to pick a rate conservatively. Lower Rate means Smaller Chunk: Requesting a smaller chunk means a lower probability to obtain fair share. More information? Read our paper! http://www.stanford.edu/~huangty/IMC.pdf Recipient of IETF/IRTF Applied Network Research Prize Bandwidth Under-estimation Conservatively Request for a smaller chunk Video Client Competing Flow Generator

HTTP-based Video Streaming - Stanford University · 2013. 4. 10. · Serve the video with quality 1750kb/s Playout Buffer Standardized, commoditized HTTP servers Videos are pre-encoded

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HTTP-based Video Streaming

Confused, Timid, and Unstable: Picking a Video Streaming Rate is HardTe-Yuan Huang, Nikhil Handigol, Brandon Heller, Nick McKeown, Ramesh Johari

Experimental Setup

The$Internet$

Video Client

The$Internet$

Bandwidth$Controller$

CDN$1$

CDN$2$

CDN$3$

Content$Distribu9on$Networks$

CDN A

Get File 1 (1750kb/s), Chunk 1

Serve the video with quality 1750kb/s

Playout Buffer Standardized, commoditized HTTP servers

Videos are pre-encoded and deployed in CDNs

Rate selection logic resides at the client side

File%1:%

File%2:%

1750% 1750%

1050% 1050%

Problem

0 100 200 300 400 500 600 700 800 900Time (s)

235375560750

105014001750

2500

3000

4000

5000

kb/s

Avai

labl

e Vi

deo

Rat

Video Flow Throughput

Competing Flow Throughput

Video Rate

Fair Share

In the presence of a completing flow, video quality steps down all the way to the lowest

Why? Here is the answer!

Download and

MeasurePick a Rate

Initial Bitrate

BandwidthEstimation

Video Rate for the Next Chunk

Bandwidth Under-estimation: The ON-OFF traffic pattern periodically resets TCP congestion window.Pick a Rate Conservatively: Since the estimated bandwidth typically is not equal to the actual bandwidth, video clients tend to pick a rate conservatively.Lower Rate means Smaller Chunk: Requesting a smaller chunk means a lower probability to obtain fair share. More information? Read our paper!

http://www.stanford.edu/~huangty/IMC.pdfRecipient of IETF/IRTF Applied Network Research Prize

BandwidthUnder-estimation Conservatively

Request for a smaller chunk

Video Client

Competing Flow Generator