Optimizing a 3D Audio Teleconference Application · Contents Motivation and Concept Overview...
Transcript of Optimizing a 3D Audio Teleconference Application · Contents Motivation and Concept Overview...
Interactive Communication Systems (ICS)Wilhelm-Schickard Institute - Dr. Christian Hoene
© 2010 Universität Tübingen, WSI-ICS
Mansoor Hyder, Michael Haun, Dr. Christian Hoene
ETSI-QoS QoE User Experience Workshop, Sophia Antipolis, September 21-22, 2010
Optimizing a 3D Audio Teleconference Application
Contents
Motivation and Concept
Overview
Methodology
Test Design
Results
Summary
Future Work
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Drawbacks of Classic Telcos
Teleconferencing offers advantages Allows collaborative communication
Saves traveling time and costs
Overcoming of geographical separations
Teleconferencing displays shortcomings No significant improvement of audio quality over time
Competition between interactivity and number of users
Competition between understandability and number of users
User expectations not satisfied
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Spatial Audio for Telcos
Incorporating 3D spatial audio provides natural communication feeling...
… but not all researchers reported an increase in quality …
… thus further measures have to be taken to optimize spatial audio teleconferencing, e.g. Proper selection of virtual environment
User opinions4Optimizing a 3D Audio Teleconference Application
Optimizing Spatial Audio Teleconferencing
Careful selection of virtual acoustic parameters Room size
Participants sitting arrangement
Conference table size
Number of simultaneous talkers
Simultaneous talkers voice characteristics
User opinions on Easiness to locate talker of choice
Spatial Audio Quality
Overall Audio Quality and comparison with natural communication
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Our 3D Telephone System
3D Telephony Open source
Based on Uni-Verse [1]
Optimized to be used with Ekiga Softphone
Customizable virtual environment
Previous work Implementation of prototype
User studies
Opinions on Audio Quality
Studying various placement of participants
[1] Raine Kajastila, Samuel Siltanen, Peter Lunden, Tapio Lokki, and Lauri Savioja. A Distributed real-time virtual acousticrendering system for dynamic geometries. In 122nd Convention of Audio Engineering Society (AES), Vienna, Austria, May 2007.
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Methodology
Conduction of listening-only tests on locatability and quality (MOS)
Using cubic virtual rooms with round conference table placed in center
Analyze the influence of Voice characteristics
Number of concurrent talkers
Table size
Sound Source position density
Room size
Comparison of each setup with reference setup
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Listenings-Only Tests and Audio Samples
Participants 31 subjects, 13 Female, 18 Male
Average Age 27 years
Normal listening ability
Good to professional level computer proficiency
8 subjects had previous listening only test exposure
Audio samples Male/Female anechoic voice samples
ITU-T Rec P.50 Appendix 1 Library
Prerecorded from and processed with Uni-Verse
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Test Design - Setups
Five setups Two tests per setup
One reference test
11 test, 2201 audio samples in total
Series of three tests for each parameter Reference, Tested-Parameter-1, Tested-Parameter-2
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Test Parameters
Talkers' voice characteristics m/m, f/f or f/m talker combination
Number of concurrent talkers 2, 3 or 4 simultaneous talkers
Table size Radii of 2, 3 or 4 m
Number of sound source locations 4, 6 or 8 possible talker locations
Room size Room sizes of 20x20x20m, 15x15x15m or 10x10x10m
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Overview
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An schematic overview of the virtual test environment and all measured parameters
Voice Characteristics
Opposite gender talkers easier to localize
Female/Female hardest to localize
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Number of Talkers
Localization performance increases with number of talkers
Subjective localizing easiness decreases
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Table Size
Localization performance increases with table size
Subjective localizing easiness stable
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Talker Location Density
Localization performance decreases with increase in talker location density
Decrease in MOS-LQSW- easiness values
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Room Size
Localization performance decreases with increasing room size
Better MOS values with medium size room
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Audio Quality
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MOS-LQSW for spatial quality and overall audio quality achieved nearer values throughout the test
Better MOS-LQSW values for spatial quality and overall audio quality were observed for mix gender talker test and medium sized room
Summary
Each parameter has substantial influence on talker locatability
Mixed gender talkers were found easier to localize
An increase in table size brought increase in localization performance with no significant difference found in MOS-LSQW-localization easiness values for all table sizes
An increase in possible talker locations resulted a significant decrease in localization and MOS-LSQW localization easiness values
Decrease in room size resulted an increase in localization performance
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Future Work
Adding MEMS based head-tracking to “3DTel”
Mapping user position and orientation in a room
Study possibilities to use WiiMote as a head-tracking device
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