an experiment to characterize videos on the web l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
An Experiment To Characterize Videos On The Web PowerPoint Presentation
Download Presentation
An Experiment To Characterize Videos On The Web

Loading in 2 Seconds...

play fullscreen
1 / 27

An Experiment To Characterize Videos On The Web - PowerPoint PPT Presentation


  • 250 Views
  • Uploaded on

An Experiment To Characterize Videos On The Web. Soam Acharya Brian Smith Cornell University MMCN 1998. www. www. www. www. Overview. Designed and implemented an experiment to search and analyze videos on the web 22500 HTML documents 57000 movies 100 Gbytes of data. Why?.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'An Experiment To Characterize Videos On The Web' - ryanadan


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
an experiment to characterize videos on the web

An Experiment To Characterize Videos On The Web

Soam Acharya

Brian Smith

Cornell University

MMCN 1998

overview

www

www

www

www

Overview
  • Designed and implemented an experiment to search and analyze videos on the web
  • 22500 HTML documents
  • 57000 movies
  • 100 Gbytes of data
slide3
Why?
  • Codec Designers
  • Network Engineers
  • Other Multimedia Researchers
      • MM file systems
  • Webmasters
questions we asked
Questions We Asked

Not all that many. We found 57,000.

  • How many movies are out there?
  • What are their basic properties?
  • What compression formats are popular?
  • How well do the formats compare?
  • Are standard modem rates enough?

90% last 45 seconds or less. 1.1 Mbytes is their median size

QuickTimeis about 53%, followed by MPEG (30%) and AVI

MPEG compresses best. QuickTime and AVI are similar.

28.8 - 128 Kilobits/sec (Kbps) are useless for real-time download and display of movies.

roadmap
Roadmap
  • Data Collection Methodology
  • Analysis
  • Results
  • Conclusion
  • Future Work
  • Open Questions
data collection methodology
Data Collection Methodology
  • Hunting Phase
    • get links to movies
  • Gathering Phase
    • download movies and gather raw statistics
  • Sifting Phase
    • eliminate outliers
early april 1997 hunting phase
Early April 1997 -Hunting Phase
  • Milked AltaVista for documents dated
    • January 1995 - March 1997
  • looked for MPEG, QuickTime, AVI
      • no streaming video format
gathering phase

www.eg.com

2. movie.html

LDG

1. http://www.eg.com/movie.html

4. summary statistics

3. my.mov

Http://www.eg.com/movie.html

http://www.cnn.com/pepe.html

…..

www.vid.com

Gathering Phase

mid April 1997 - May 1997

LP0

LP1

LP2

LDG: movie link distributor/gatherer

LP: link processor

sifting phase
Sifting Phase
  • Processed 100 Gbytes of data and 57,000 titles
    • used mpegstat and modified xanim
  • 4 <frames/sec< 40 {5000 titles}
  • duration> 0.5 seconds {1000 titles}
  • 0.6 <aspect ratio< 1.667 {1000 titles}
  • bitrate < 10 Mbps {1000 titles}
    • bitrate = (movie size)/(movie duration)
  • duplicate URL detection {1500 titles}
analysis
Analysis
  • 47500 titles remained
    • 53% QuickTime, 30% MPEG, 17% AVI
  • Can be divided into two categories
    • Distributions:
      • by date
      • fps
      • size
      • duration
      • aspect ratio
      • bitrate
    • Comparing movie formats against each other
slide11

Roadmap

  • Data Collection Methodology
  • Analysis
  • Results
  • Conclusion
  • Future Work
  • Open Questions
movie size in bytes
Movie Size (In bytes)
  • 70% of movies are 2Mbytes or less
  • Median movie size is about 1.1 MBytes
aspect ratio
Aspect Ratio
  • 74% of all files had an aspect ratio of 1.333
    • 320 x 240
    • 160 x 120
  • 89% had aspect ratios of 1.2 - 1.5
so far
So Far ...
  • Distributions:
    • by date
    • fps
    • size
    • duration
    • aspect ratio
    • bitrate
  • Comparing movie formats
avi quicktime comparison

AVIQuickTime

Audio Codec PCM PCM

MS-ADPCM TWOS

AVI/QuickTime Comparison
  • 25% of AVI, 33% of QuickTime: video only

Video CodecsAVIQuickTime

Radius Cinepak43% 60%

Intel Indeo R3.225% 2%

Microsoft Video I26% 0%

Apple Video-RPZA 0% 22%

how compare compression
How Compare Compression?
  • Bits/pixel= (video size in bits)__

(width * height * # of frames)

Mean Median (bits/pixel)

AVI 2.51 2.14

QT 2.16 1.82

MPEG 0.72 0.51

mpeg bits pixel distribution
MPEG Bits/pixel Distribution

Frame Type Mean bits/pixel Median bits/pixel

I 1.25 1.10

P 0.76 0.54

B 0.31 0.19

  • Size of I:P:B frames ~ 1: 2 : 5
  • 90% of MPEG files were video only
mpeg frame patterns
MPEG Frame Patterns

Frame Pattern % Distribution Mean

bits/pixel

I 27.1 1.17

IBBPBB 15.7 0.7

IBBPBBPBBPBBPBB 10.4 0.31

IBBPBBPBBPBB 8.1 0.5

IBBBPBBBPBBB 4.4 0.66

IPBBIBB 4.2 0.39

IIP 3.5 0.7

80% of MPEG: some recurring pattern

recap
Recap
  • Number of movies coming online - exponential, then flat
  • MPEG higher fps, QuickTime/AVI lower
  • Median size of movies: 1.1 Mbytes
  • 90% of movies last 45 seconds or less
  • 1.333 is the most common aspect ratio
  • 28.8 - 128 Kbps modem rates useless for real-time downloads
  • Radius Cinepak is widely used by QuickTime and AVI
  • MPEG compresses better than QuickTime and AVI
  • 80% of MPEGs have some sort of recurring pattern
conclusion
Conclusion
  • Existing compression technologies not enough for transmission over standard modems
    • explains rise of streaming video technologies
    • users cope by making file sizes, duration smaller
    • but not by throttling the bitrate
    • perceptual threshold?
future work
Future Work
  • How do videos age?
  • Another study to confirm findings
    • Brewster Kahle,
    • www.archive.org
  • Develop tools to automate the process
open questions
Open Questions
  • What are video access patterns on the Web?
  • How to analyze streaming video files?