Subjective Audio Quality Impairments of Playout Adaptation ...cqr2011.ieee-cqr.org/Day 2/Tech...
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Introduction Listening Test Results Summary End Subjective Audio Quality Impairments of Playout Adaptation with AAC RTP Communication J. Issing 1 N. F ¨ arber 2 1 Department of Computer Science 7 Computer Networks and Communication Systems University of Erlangen-Nuremberg 2 Audio Department Fraunhofer IIS IEEE CQR 2011, Naples, Florida, USA Issing, F ¨ arber University Erlangen, Fraunhofer IIS AAC Playout Adaptation Impairments
Transcript of Subjective Audio Quality Impairments of Playout Adaptation ...cqr2011.ieee-cqr.org/Day 2/Tech...
Introduction Listening Test Results Summary End
Subjective Audio Quality Impairments ofPlayout Adaptation with AAC RTP
Communication
J. Issing1 N. Farber2
1Department of Computer Science 7Computer Networks and Communication Systems
University of Erlangen-Nuremberg
2Audio DepartmentFraunhofer IIS
IEEE CQR 2011, Naples, Florida, USA
Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
Introduction Listening Test Results Summary End
Audio Communication
Our Vision
I We want to connect two sites to enable conversation as ifyou were in the same room.
Example: Cisco Telepresence
Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
Introduction Listening Test Results Summary End
Audio Communication
To pursuit this vision we...
I focus on full band (20 Hz to 22 000 Hz) speech & audioI can not rely on existing time stretching techniques, as
audio has neither talk spurts, nor silence periodsI use 48 kbit/s (AAC-ELD) stereo
Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
Introduction Listening Test Results Summary End
Network Packet Delay
Network Packet DelayI Packets traversing a network suffer from two main effects:
random jitter floor and delay spikes
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delay [s]
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Issing, Farber University Erlangen, Fraunhofer IIS
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Time Scale Modification
ACE Time ScalingI Shrinking is performed by dropping frames
1 2 4 5
I Stretching is performed by inserting a concealed frame
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I Adjacent audio frames overlap
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Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
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Concealment vs Stretching
gj
Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
Introduction Listening Test Results Summary End
Concealment vs Stretching
Concealment vs Stretching Listening Test
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speech 10%
stretch_010
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conceal_010
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lp35
I No significant difference between stretching andconcealment
I Speech item performed admirably well for stretching(10 ms)
Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
Introduction Listening Test Results Summary End
Time Shrinking
Time Stretching Listening Test
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squam
drop_01
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lp35
I Dropping performs very well for small drop ratesI Tonal signal suffer from phase shift artifacts (SQUAM)
Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
Introduction Listening Test Results Summary End
Further Information
The paper provides addition information aboutI The network pattern file anatomyI Oscillation resultsI Evaluation of the impairment addition model, as used by
the E-Model
Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
Introduction Listening Test Results Summary End
Fine
Thanks for your attention!
Issing, Farber University Erlangen, Fraunhofer IIS
AAC Playout Adaptation Impairments
