Perspectives, Frame Rates and Resolutions: It's all in the Game

Mark Claypool Kajal ClaypoolWorcester Polytechnic Institute

Worcester, MA, USA

http://www.cs.wpi.edu/~claypool/papers/perspective/

MIT Lincoln LabsLexington, MA, USA

FDG, Orlando, FL, USA 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 (4 GHz P4, 512 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”– Can we guide by science?

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Related Studies• Passive Users [1,10,12,20,22,24,25]

– Users assess video with various frame rates and resolutions

– Generally, decrease resolution decreases perceived quality, but decrease in frame rate less so

• Active Users [14,15,16,18,23]– Users perform tasks under various frame rates

and frame resolutions– Generally, extremely low frame rates impact

performance, but frame rates of 5+ acceptable• Games [3,5]

– Different than video: frame rate matters, not resolution

– But First Person Shooters only• Our goal – Effects of Frame Rate and Frame

Resolution on User Performance for Games

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Effects of Frame Rate and Resolution

• Impact of frame rate and resolution depends upon action in the game– Consider fundamental actions: shooting

and navigating• Hypotheses

1. Shooting greatly impacted by frame rate

2. Navigating less impacted by frame rate3. Resolution has little impact on player

performance4. 1-3 hold across game genres based on

camera perspectives

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Outline

• Introduction (done)• Game Perspectives (next)• Approach• Results• Conclusions

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Game Perspectives• Based on:

– placement of camera with respect to the avatar

– visual change in object sizes relative to camera

First Person Linear

Third Person LinearThird Person Isometric

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Methodology

• Develop games• Build test harness• Setup environment• Solicit users• Analyze results• Disseminate (this talk )

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Game Development

• Implementation using Game Maker w/stock art• Three games (1st, 3rd linear, 3rd isometric)• Two levels (navigating and shooting) for each

game• Normalized so rates of shooting and navigating

same across genres

Third Person Isometric

Third Person Linear

First PersonLinear

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Test Harness• In Visual Basic• Tutorials on

navigation level, shooting level

• 36 game sessions (3 perspectives, 4 frame rates, 3 resolutions)– 15 seconds each

session– Took ~15 minutes

total

• Questionnaire at end of each session

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Experiment Environment

• Campus computer lab• Dell Precision 380 Computers

– Pentium D 3.0 GHz Dual Core – Dell 1907 Flat Panel displays– 2 GB of RAM– Monitor resolution 1280x1024 pixels

• Users kept at least one computer apart– Reduce distraction from adjacent people.

FDG, Orlando, FL, USA 12

User Solicitation

• Flyers posted around campus• Oral announcements in courses• Email to various student groups• Enticed with:

– Raffles for $25 Best Buy gift certificates– Extra credit for select academic courses

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Outline

• Introduction (done)• Game Perspectives (done)• Approach (done)• Results (next)

– Demographics– Navigating– Shooting– Perception

• Conclusions

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User Demographics

• 27 users• Most CS undergraduates• 89% male• 74% 16-25 years• 60% played 6+ hours of games per

week– Time correlated with user performance

• 25% casual gamers• 50% hardcore or almost hardcore

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Navigating versus Frame Rate

• Distinct trendlines suggests 3rd isometric easiest• Slight increase with frame rate for 1st and 3rd linear

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Navigating versus Resolution

• Distinct trendlines • Flat with resolution

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Shooting versus Frame Rate

• 3rd isometric highest, easiest to locate target• 1st and 3rd linear overlap• “Knee” at 15 f/s (7 f/s unplayable for 1st and 3rd linear)

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Shooting versus Resolution

• Distinct 3rd iso • Flat with resolution

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Playability and Quality

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Conclusions• Frame Rate larger impact on performance than

Resolution– Frame Rate critical for adequate game performance

• Marked drop in performance below 15 fps– Resolution has little effect on user performance

• Users as effective from 800x600 to 1280x1024– Holds across all perspectives and actions

• Frame Rate and Resolution both important for user perception– Playability mirrors frame rate– Quality slight upward trend with resolution

• Dramatically different previous research on video– Showed converse, that Resolution mattered more– Suggests challenges in designing devices for games

and video

Perspectives, Frame Rates and Resolutions: It's all in the Game

Mark Claypool Kajal ClaypoolWorcester Polytechnic Institute

Worcester, MA, USA

http://www.cs.wpi.edu/~claypool/papers/perspective/

MIT Lincoln LabsLexington, MA, USA