MediaPlayer vs.
™
™
RealPlayer
A Comparison of Network Turbulence
Mingzhe Li, Mark Claypool, Robert Kinicki
CS Department
Worcester Polytechnic Institute
Worcester, MA, USA
http://perform.wpi.edu/
Introduction
•
Streaming video often does not like TCP
•
UDP flows may be unresponsive to congestion
•
•
– Wants smooth stream, so rate-based
– Does not always want retransmissions
!Chooses UDP
!Handle with Active Queue Management (AQM)
•
Typical AQMs model UDP flows as CBR (“firehose”)
More realistic models of streaming UDP flows will
make AQMs more effective
We investigate size and distribution over time
•
Big 3: RealPlayer, MediaPlayer, QuickTime [Jup01]
! Turbulence
November 2002
SIGCOMM Internet Measurement Workshop
Methodology
• Build automated video players
(MediaTracker and RealTracker [WCZ01])
– Use commercial cores
– Software Development Kits (SDKs)
– Record application stats: frame rate…
• Select hosts with both RealNetworks and
•
•
Microsoft Media video servers
Stream identical content to players on the
same host
Analyze results
November 2002
SIGCOMM Internet Measurement Workshop
Clip Selection
1
2
3
4
5
6
Type
Sports
3:46
Commercial
0:39
Sports
0:60
Music T.V.
4:05
News
1:47
Movie Clip
2:27
November 2002
Bandwidth
High
Low
High
Low
High
Low
High
Low
High
Low
Very High
High
Low
Real
(Kbps)
284
36
268
84
284
37
181
26
218
22
637
271
39
Microsoft
(Kbps)
323
50
307
102
307
38
309
50
250
39
731
347
102
SIGCOMM Internet Measurement Workshop
Experimental Setup
•
Player Platform
•
Network
•
Software
– Microsoft Windows 2000 PC
– P4 1.8 GHz, 512M RAM, AGP 32MB video card
– mindspeed.wpi.edu (Worcester, MA, USA)
– LAN: PCI 10M NIC Win2k professional
– Campus uplink: ~50 Mbps (Yipes in 15 Mbps)
– Microsoft Media Player version 7.1
– RealNetworks RealOne Player build 6.0.10.505
– Ethereal version 0.8.20
November 2002
SIGCOMM Internet Measurement Workshop
IP Packet Arrivals
1755
Real Play (217K)
825
1750
Windows Media Player (250K)
820
1745
815
1740
810
1735
805
1730
800
1725
795
1720
790
30
•
•
830
30.2
30.4
30.6
Time (Seconds)
30.8
RealPlayer – single packets
Media Player – groups of packets (3 in this example)
– 2 at about 1500 bytes (typical MTU)
– 1 “left-over” less than MTU
November 2002
SIGCOMM Internet Measurement Workshop
31
Media Packet Number
Real Packet Number
1760
IP Packets w/out UDP Header
Media Player IP Packet
Fragmentation
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0
200
400
600
Encoded Bandwidth (Kbits/s)
November 2002
SIGCOMM Internet Measurement Workshop
800
Normalized UDP Packet Sizes
0.8
Probability Density
0.7
Real Player
0.6
Windows Media
0.5
0.4
0.3
0.2
0.1
0
0
0.5
1
1.5
Normalized Packet size
Media Player – More “Constant Packet Size”
RealPlayer – Less “Constant Packet Size”
November 2002
SIGCOMM Internet Measurement Workshop
2
UDP Packet Interarrival Times
1
Cumulative Density
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
Real Player
Window Media Player
0.1
0
0
0.5
1
1.5
2
2.5
Normalized Interarrival Time Interval
Media Player – More “Constant Packet Rate”
RealPlayer – Less “Constant Packet Rate”
November 2002
SIGCOMM Internet Measurement Workshop
3
Playout Rate
Bandwidth (Kbits/sec.)
700
Real Player (284K)
600
Real Player (36K)
500
Windows Media Player (323K)
400
Windows Media Player (49K)
300
200
100
0
0
50
100
150
200
Time (seconds)
RealPlayer buffers at a higher rate
November 2002
SIGCOMM Internet Measurement Workshop
250
Frame Rate
35
Frame Rate (fps)
30
25
20
15
Real Player
10
Media Player
5
0
200
400
600
Average Bandwidth (Kbits/sec.)
RealPlayer significantly higher at low
bandwidth
November 2002
SIGCOMM Internet Measurement Workshop
800
Summary
• Microsoft Media Player typical CBR
– Constant packet sizes and interarrivals
• RealNetworks RealPlayer less CBR
– Range of packet sizes and interarrivals
– Buffers at up to 3 times playout rate
• Media Player has significant IP frag.
– 3-5 IP frags / UDP for broadband+ bwidth
• Results can be used for more realistic
•
streaming simulations and emulations
MediaTracker and RealTracker online:
http://perform.wpi.edu/real-tracer/
November 2002
SIGCOMM Internet Measurement Workshop
Future Work
• Build simulated streaming application
– In NS
• Server side control
– Clip encoding, Content type
– (We have server set-up, preliminary results)
• Bandwidth under congestion
– TCP-Friendly?
– (We have results for RealPlayer)
• More players and protocols
– QuickTime (QuickTracker)
November 2002
SIGCOMM Internet Measurement Workshop
MediaPlayer vs.
™
™
RealPlayer
A Comparison of Network Turbulence
Mingzhe Li, Mark Claypool, Robert Kinicki
CS Department
Worcester Polytechnic Institute
Worcester, MA, USA
http://perform.wpi.edu/