We conduct real experiments to quantify user satisfaction in mobile cloud games using a real cloud gaming system built on the open-sourced GamingAnywhere. We share our experiences in porting GamingAnywhere client to Android OS and perform extensive experiments on both the mobile and desktop clients. The experiment results reveal several new insights: (1) gamers are more satisfied with the graphics quality on mobile devices, while they are more satisfied with the control quality on desktops, (2) the bitrate, frame rate, and network delay significantly affect the graphics and smoothness quality, and (3) the control quality only depends on the client type (mobile versus desktop). To the best of our knowledge, such user studies have never been done in the literature.

1. Quantifying User Satisfaction
in Mobile Cloud Games
Chun-Ying Huang, Cheng-Hsin Hsu, De-Yu Chen, and
Kuan-Ta Chen
ACM MoVid 2014, Singapore
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2. Mobile Games
• Mobile games are hot!
• in 2011, 59% smartphone users played mobile games [1]
• by 2016, mobile game market will grow to 16 billion USD [2]
• Mobile games are less visually appealing, because of
the limitations on
• CPU/GPU power
• memory space/speed
• network bandwidth
• battery capacity
• Possible solution: mobile cloud gaming
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[1] http://www.infosolutionsgroup.com/popcapmobile2012.pdf
[2] https://www.abiresearch.com/research/product/1006313-mobile-gaming

3. What is Mobile Cloud Gaming
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Real-time game playing using light-weight mobile clients

4. Cloud Games on Mobile Devices
• Mobile cloud gaming has many benefits
• better visual quality  attract serious gamers
• lower porting effort/cost  more games
• lower battery consumption  longer play time
• But, most cloud games are played on PCs and TV set-
top boxes
• steep development cost  most SDKs [CloudCom’13, NOSSDAV’13,
MM’11] are proprietary
• high bars on gamer satisfaction  high-quality + low latency
• We address these two challenges in this work
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5. GamingAnywhere: An Open Source Project
• We, researchers, have tons of ideas to improve cloud
gaming services, but all cloud gaming systems are
proprietary and closed
• GamingAnywhere is the first cloud gaming platform for
researchers, developers, and gamer
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6. 6
http://gaminganywhere.org/
• In 10 months
• Web: 31,897 visits, 20,019 unique visitors
• Forum: 106 topics, 357 posts

7. Visitor Distribution
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8. Our Two Contributions
• First, we optimize GamingAnywhere client on Android
device
• the first transparent cloud gaming platform  researchers,
developers, and gamers may run any PC games using our client
• Second, we conduct extensive user studies
• various GamingAnywhere configurations with diverse resolutions,
frame rates, bitrates, and network delays are applied to desktops
and mobile devices  many new insights
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Cloud
Server
Mobile
Client
Networks

9. Porting Client to Android
• Challenges
• short system delay: wireless networks incur longer latency
• efficient implementation: limited computation power and battery life
• user-friendly controller: no physical inputs (buttons and joysticks)
and small screen size
• Solution approaches
• enable hardware A/V decoders  faster decoding and lower
energy consumption
• realize proof-of-concept controllers as overlays  the best
controller design is out-of-scope
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10. Mobile Client Architecture
• Implemented by leveraging open-source packages
• Support S/W and H/W decoders
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Built-in H/W
Decoders
S/W Decoders

11. Controllers
• Implement three proof-of-concept controllers, designed for
• Nintendo 64
• Nintendo DS
• Limbo
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Nintendo 64 Controller Limbo Controller

12. User Interface
• Setting profiles and start games
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13. Demo
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14. Testbed for User Studies
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GamingAnywhere
ServerLAN
GamingAnywhere
Desktop Client
WiFi APGamingAnywhere
Mobile Client
• To understand how device type, game genre, resolution,
bitrate, frame rate, and network delay affect user
experiences

15. Experiment Settings
• Limbo, Mario Kart, Super Mario, Super Smash Bros
• 10 male and 5 female subjects between 21-34 years old
• Configurations (each subject try all 68 configurations)
• Resolution: 640x480, 960x720, 1280x960
• Bitrate: 1, 3, 5 Mbps
• Frame rate: 5, 20, 50 fps
• Network delay: 0, 150, 300 ms
• MOS score (1-5) on
• Graphics
• Smoothness
• Control
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16. Mobile versus PC
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PCs have many
physical keys
The implementations
are efficient
Really? Mobile
is better?

17. Why Mobile Performs Better in Graphics?
• First, subjects may have lower expectation on graphics of
mobile devices
• Second, smaller screen sizes make graphics imperfection
less noticeable
• Observation: The satisfaction levels
are based on observed flaws than
absolute quality!
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18. Impacts of Different Game Genres
• Subjects are more sensitive to graphics quality in Limbo
than in Mario Kart
• Mario Kart is a fast-paced racing game, while Limbo is rather static
• Subjects are less sensitive to controls in platform games
(Limbo and Super Mario) than in fighting (Super Smash
Bros.) and racing (Mario Kart) games
• Gamers face AI opponents in fighting and racing
games
• Gamers have enough time to prepare in platform
games
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19. Different Configurations
• Graphics quality is affected by bitrate (dominating) and
frame rate (weaker)
• Resolution has no impact on graphics quality (surprising)
• We suspect: (1) games are not too complex and (2) mobile client
always up-scales the video  Through analysis is our future task
• Smoothness is affected by network delay, frame rate, and
bitrate  We suspect low graphics quality leads to low
MOS score, more analysis is our future work
• Control is only affected by client type (PC versus mobile)
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20. Conclusion
• We presented the optimized Android Gaming-
Anywhere client
• We conducted extensive mobile cloud gaming
user studies, which reveal three main insights
1. Gamers are more satisfied with the graphics quality
on mobile devices
2. The bitrate, frame rate, and network delay affect the
graphics and smoothness quality the most
3. The control quality is only affected by client type (PC
versus mobile)
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21. QUESTIONS?
Join us at http://gaminganwhere.org
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22. BACKUP
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