The Effects of Frame Rate and Resolution on Users Playing First

Person Shooter Games

Mark Claypool

CS DepartmentWorcester Polytechnic

Institute

http://www.cs.wpi.edu/~claypool/papers/fr-rez/

Kajal ClaypoolFeissal Dama

CS DepartmentUniversity of Massachusetts,

Lowell

January 2006MMCN, San Jose, California 2

Computer Games and Performance

• Latest computer games push capabilities of hardware in “quest” for more detailed, realistic graphics

• Single game runs on varied hardware– PC : Old (600 MHz P3, 32 MB Video) or New (3 GHz P4, 256 MB Vid)

– Platform: PC, Console (i.e. Xbox), Hand-held (i.e. PSP)– Result: Uneven hardware capabilities, opportunities for

performance tuning

• Key factors for game performance are:– Frame Rate – higher frame look smoother, provide

more temporally precise feedback– Frame Resolution – higher resolutions look better,

provide more visually precise feedback

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Motivation

• Unfortunately, often cannot have both high Frame Rate and high Frame Resolution– Ex: Hand-held devices have constrained resources

(small screens, limited power)– Ex: Older computers (often, only 1 year!) cannot run

latest games at maximum frame rate or resolution

• Tradeoff between Frame Rate and Frame Resolution– Higher resolutions mean lower frame rates and vice

versa

• How are frame rates and resolutions chosen?– Game console designers and hand-held designers

choose resolution for user•Frame rate may depend upon processing load

– PC gamers choose it by “feel”– Not guided by science

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Related Studies

• Passive Users [1,2,3,4,5,6,7]– Users assess video with various frame rates and

resolutions– Generally, decrease resolution then decrease

quality, but decrease in frame rate less so • Active Users [8,9,10,11]

– Users perform tasks under various frame rates and frame resolutions

– Generally, extremely low frame rates impact performance, but frame rates of 4+ can be acceptable

• Overall - more passive than most games and tradeoffs not compared

• Our goal – Effects of Frame Rate and Frame Resolution on User Performance for Games

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Outline

•Introduction (done)

•Methodology (next)

•Results

•What’s Going On?

•Conclusions

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Methodology Outline

•Select game

•Build custom map

•Select parameters

•Build test harness

•Solicit users

•Analyze results

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Methodology – Select Game

• First Person Shooter (FPS)– Popular genre, especially for online play– Requires intense player interaction with time-critical

decisions•Impairment to the display quality can cost virtual lives

• Quake III Arena– Still fairly popular (~700 active servers via GameSpy)– Representative of current FPS games in terms of

perspective, weapon choices and gameplay – Allows control of frame rate and resolution at startup

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Methodology – Custom Map

= spawn point

Opponent Platform

(Chasm)

User Platform

• Minimize effects of other players– Use Bot (Xaero)

• Minimize movement– Chasm cannot be

jumped– Wall behind player so

doesn’t fall off accidentally

• Maximize aiming and shooting– No cover (save wall to

protect spawn point)– Use of railgun that

cannot be rapidly fired– One shot per kill

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Frame rate: 30, Resolution: 640x480

Example

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Methodology – Demographics

Demographics provided once, before maps started

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Methodology – User Perception

User perception provided after each map played

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Methodology – Parameters

•5 frame rates: 3, 7, 15, 30 and 60 fps – Ranges previously studied– May appear during normal game play

•3 frame resolutions: 320×240, 512×384, 640×480

– Hand-held devices to low-end PCs– Observed trend may interpolate to higher

resolutions

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Methodology –Test Harness

For each player …

• Gather demographics

• Play Quake III– Very high frame rate (80 fps)– Very high frame resolution (1024×768 pixels)

• Shuffle (Frame Rate, Frame Resolution) combos

• For each combo …– Play Quake III with (Frame rate X, Resolution Y)– Gather user perception

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Methodology – User Solicitation

•Two-week period

•Game played on isolated PC in lab

•Range of enticements:– Enter raffle for three $50 gift certificates– Extra credit for courses– Refreshments for participants

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Outline

•Introduction (done)

•Methodology (done)

•Results (next)

•What’s Going On?

•Conclusions

January 2006MMCN, San Jose, California 16

Aggregate Statistics

• 60 users provided “clean data” – 64 participated, but 4 removed because ended

early• Age:

– Most (~75%) 16-25 years old (ugrad CS students)– Almost 25% over 25 years old (grad CS students)

• Gaming:– Over 65% played games over 1 hour per week– 25% played 6+ hours per week– 50% casual gamers, moderate at shooters

• Gender:– About 20% female

•Only one more than casual gamer, compared to about 65% for males

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Performance and Frame Rate

(Resolution: 512x384 pixels)

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Performance and Frame Resolution

(Frame Rate: 15 fps)

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Perception and Frame Rate

(Resolution: 512x384 pixels)

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Perception and Frame Resolution

(Frame Rate: 15 fps)

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Outline

•Introduction (done)

•Methodology (next)

•Results (done)

•What’s Going On? (next)

•Conclusions

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60 fps 15 fps

7 fps 3 fps

Effects of Frame Rate on User Performance

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Example – 15 Frames per Second

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Example – 7 Frames per Second

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Example – 3 Frames per Second

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Effects of Frame Resolution on User Performance

640 x 480 320 x 240

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Example – Resolution 320x240

Frame rate: 30

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Conclusions• Frame Rate larger impact on performance than Frame

Resolution– Frame Rate critical for adequate game performance

•Frame rates of 3 fps and 7 fps not playable•60 fps provides 7-fold increase over 3 fps

– Frame Resolution has little effect on user performance•Users as effective at 320×240 as at 640×480

• Frame Rate and Frame Resolution both important for user perception– Effect of frame resolution similar to effect of frame rate– Top frame rate tested (60 fps) shows limit– Top resolution tested (640x480) not at limit

•Perceived quality increases linearly with square pixels• Dramatically different previous research on video

– Showed converse, that Frame Resolution mattered more– Suggests challenges in designing devices for games and

video

January 2006MMCN, San Jose, California 29

Future Work

•Other aspects of First Person Shooters– Different map conditions– Movement

•Other display tradeoffs– “Quality” from graphics effects

•Anti-aliasing, realistic water/grass …

•Additional demographics studies– Gender, age, gaming experience …

•Other computer games– Real-Time Strategy, Sports …

The Effects of Frame Rate and Resolution on Users Playing First

Person Shooter Games

Mark Claypool

CS DepartmentWorcester Polytechnic

Institute

http://www.cs.wpi.edu/~claypool/papers/fr-rez/

Kajal ClaypoolFeissal Dama

CS DepartmentUniversity of Massachusetts,

Lowell