40
Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality? ACM MM’11 Presenter: Piggy Date: 2012.05.07

Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

  • Upload
    jennis

  • View
    49

  • Download
    0

Embed Size (px)

DESCRIPTION

Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?. ACM MM’11 Presenter: Piggy Date: 2012.05.07. Outline. Introduction Related Work User Study Result Discussion and Conclusion. Introduction. Mobile video service is getting popular - PowerPoint PPT Presentation

Citation preview

Page 1: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Saving Bitrate vs. Users: Where is the Break-Even Point in

Mobile Video Quality?ACM MM’11

Presenter: PiggyDate: 2012.05.07

Page 2: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

OutlineO Introduction

O Related Work

O User Study

O Result

O Discussion and Conclusion

Page 3: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

IntroductionO Mobile video service is getting popular

O Due to the development of mobile device

O Minimizing video bitrate is importantO Wireless networks prefer low bitrate to

adapt to different bandwidth conditionsO Users prefer low bitrate as most network

providers normally charge for data usageO Video providers need to save costs

associated with serving the content

Page 4: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

IntroductionO However……

O Low video bitrate => poor video quality

O Fortunately……O Nonlinear relationship between

perceived quality and video bitrate

Page 5: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

IntroductionO Goal: To find the most efficient

bitrate requirement thatO Optimizes bandwidth usageO Maintains good user viewing

experience

O Lowest acceptable video quality vs. lowest quality for long term viewing

Page 6: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

IntroductionO Contribution

O Mapping of video bitrates to the subjective judgment of quality pleasantness

O Impact of content type, video encoding parameters and user profile on mobile video viewing experience

O Users’ selection processes and their criteria for the lowest pleasing quality for different content type

Page 7: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Related WorkO Users’ requirements for mobile video

depends onO Social and psychological factors

O Consumption model, service, user profile, context, etc…

O Video qualityO Spatial and temporal resolutionO QuantizationO Motion and texture complexity

Page 8: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Related WorkO Factors influence the reduction of

bitrateO ResolutionO Frame rateO Quantization

O And the degradation in perceived video quality is not proportionate to the decrease in bitrate

Page 9: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Related WorkO Subjective assessment

O ITU recommendation: scale-based subjective assessmentO 5/9/11-sclaesO Overburdens participants

O Binary choice method for assessing acceptability

Page 10: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Related WorkO Though previous works have

identified the lowest acceptable quality levelO They were restricted by the

technology and device at that time.O Different resolutionO People behaviors have changed (got

used to HD quality)

Page 11: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Equipment

O iPhone 3GS with 16GB storageO Display: 480x320 pixelsO H.264/AVC

O Up to 1.5 Mbps, 640x480 pixels, and 30 frames per second

O AAC-LC audio formatO Up to 150 kbps, 48kHz

Page 12: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Test material - 5 content types

O News, music, animation, sports and movie

Page 13: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Test material – encoding using 3

parametersO Quantization parameters (QP)O Spatial resolution (SR)

O 320x240, 480x320, and 640x480O Frame rate (FR)

O Divided into 3 groups based on SR:L, M and H with each group contain 10 test clipsO 30 test clips for each content type

Page 14: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Total 150 test clips

O 30x5

Page 15: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Participants

O Lounge area outside of a university library

O 40 participantsO Equal number of males and femalesO Age range: 17 ~ 35 (average = 23.2)

O User profile collectionO Experience of using mobile videoO Preference for content types

Page 16: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Participants’ profile

Page 17: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Procedure

O Scenario explanationO 3 steps within 20-25 mins for data

collectionO Participant’s profile collectionO Participant randomly chose the video

contentsO A short interview

Page 18: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Customized iPhone application

O Participant profile collectionO Content type choiceO History reviewO Quality adjustment

O AscendingO Descending

Page 19: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User Study

Page 20: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User Study

Page 21: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

User StudyO Interview

O What criteria did you use to select the desired video quality?

O Is there any difference between your criteria for different content type? Why?

Page 22: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

ResultO Acceptability calculation

O Lower than the selected lowest acceptable clip => 0

O Otherwise => 1 O Refers to the percentage of participants accepting a

video quality as the lowest quality

O Binary Logistic RegressionO Video encoding parametersO Content typeO Viewing orderO User profile

Page 23: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Acceptability and Encoding Parameters

O Different fromO Content to contentO Resolution to resolution

O Movie is the lowest while new is the highest

O The difference reduces as the resolution increases

Page 24: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Acceptability and Encoding Parameters

Page 25: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Acceptability and Encoding Parameters

O Acceptability groupO 0 – 40% should be avoidedO 41 – 60% critical stateO 61 – 80% can please usersO 81 – 100% high user satisfaction

Page 26: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Acceptability and Encoding Parameters

O Bitrate-acceptability curves

Page 27: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Acceptability and Encoding Parameters

O Bitrate-acceptability curves

Page 28: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Acceptability and Encoding Parameters

O Bitrate-acceptability curvesO High resolution needs a higher

bitrateO The acceptability of “sport” rises

slower than other content typesO Mapping of bitrate to acceptability

Page 29: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Influencing factors on quality Acceptability

O Significant factorsO Quantization parameterO Spatial resolutionO Frame rateO Content typeO GenderO Frequency O DurationO Viewing order

O Non-significant factorsO Age

Page 30: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Influencing factors on quality Acceptability

O Effect of content typeO Movie vs. music, news, and animationO Spatial resolution decreases => content type

more significant

O Effect of encoding parametersO Video quality increases with

O Decrease of QP (great difference among adjacent QP values)

O Increase of SRO Increase of FR

Page 31: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Influencing factors on quality Acceptability

O Effect of viewing orderO Acceptability in descending order is

lower than ascending orderO Significant for animation, music, news

and sports but not for movie

Page 32: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Influencing factors on quality Acceptability

O Effect of user profile

Page 33: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Influencing factors on quality Acceptability

O Effect of user profileO Gender vs. frequency

Page 34: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Influencing factors on quality Acceptability

O Effect of user profileO duration vs. frequency

Page 35: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Influencing factors on quality Acceptability

O Effect of user profileO Users’ preference

Page 36: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Quality selection patterns

O Average time spent on switching is different from content type to content typeO News is the lowest

Page 37: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Quality selection patterns

O Two selection patternsO Directly choose the target qualities

without hesitation – mostly in ascending order

O Bounced to and from the lower of higher quality for comparison – mostly in descending order

Page 38: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Criteria of acceptability quality

O Users have different assessment criteria for different content typesO Movie – high quality required (HD quality)O News – audio quality and sync.O Music – audio qualityO Animation – fewer requirement O Sport – higher quality needed when small objects

appear

O Users’ preference leads to different result on the same content typeO Ex: sport and news

Page 39: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

Discussion and Conclusion

O Users’ profile mattersO The result is different from previous worksO Exact required bitrate still depends on

individual video, here only gives a estimated range

O Platform dependency as well as video codecs

O Fixed vs. adjustable service?O Prediction model and optimal delivery

strategy

Page 40: Saving Bitrate vs. Users: Where is the Break-Even Point in Mobile Video Quality?

The EndOThanks for your attention