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Video conferencing latency measurement
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LatencyMeasurement
Vista review Feb 27, 2007
Don WelchVideo Test Methodologies
Signal processing
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Photodiode
Reference
Photodiode
FPGA
FPGA
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September Results Calibration Studio Characterizations
• Results:• Measurements Delta Time (ms) • E-H (Cal Studio to Monster B) ~ 580 ms / 290 (one
way): 270 (JT)
HV
EN
Hai Vision
Scalar S-VideoVGAPlasma
Scope
Halo
480i HaiVision
S-Video
Halo 4L Calibration Studio Halo 4L Monster Garage B
Halo
Hai Vision
ScalarS-Video VGA Plasma
480iHaiVision
S-Video
Banner Optical Fiber
• Learning: ● Fiber optic light guide makes can replace a mirror
Halo Encode to Halo Decode (Corvallis - Tokyo)
• 960 RTT / 480 one way
• Learning: ● One way delay can be deduced from RTT (Round Trip delay
Time). This was unknown to Sachs-Goldman (would buy it from us!)
HV
EN
Decoder Scalar?-Video
Screen
Scope
Sachs-Goldman
Projector
720P
ScalarEncoder
?-Video
Halo 4L Conference Area Halo Tokyo
Halo
Mirr
or
Hai Vision ScalarS-Video VGA Plasma
480iHai
Vision S-Video
FPGA Option• Initial algorithm
development on FPGA Implementation w/ Spartan 3E Starter Kit: $149 board.
• Development platform where learning can be applied for other pipeline functions.
• Flexible- USB, RS232, IP interfaces.
• Real-time requirements met for high resolution signal processing.
Initial concept evaluated
• System pipeline from camera to Pericles through gig-switch to VLC on a separate PC.
September Collaboration Characterizations
• Results:• Measurements Time (ms) Signal Type• BC 10L or 4U 96 ms Laptop-Colab• BC 10L to 4U 118 ms Laptop-Colab• BC 10L to Palo Alto 127 ms Laptop-Colab• BC 10L to 4U to Bristol 170 ms Laptop-Colab
WXGAPlasma
Scope
Halo
Extron Room Server
VGA
Halo 10L Collaboration System (Laptop Flashing )
HV
EN
VGA
• Learning: ● Flashing Power
Point works ● As rooms are
added the delay grows
Embedded Solution
