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Feature-cluster driven VQA Framework. Vladimir Zlokolica VQEG-JEG, Hillsboro, Oregon Dec. 2011. Digital Video Transmission chain. Capturing Device. Video Quality Assessment processing platform. IP Broadband Services and Applications. Set-Top Box. Digital Broadcast. HDMI.
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Feature-cluster drivenVQA Framework Vladimir Zlokolica VQEG-JEG, Hillsboro, Oregon Dec. 2011
Digital Video Transmission chain Capturing Device Video Quality Assessment processing platform IP Broadband Services and Applications Set-Top Box Digital Broadcast HDMI Digital Audio-Video Content Monitoring/Control Working Station
Main Concept • Modeling visual subjective perception on end-user device. • Combine both (i) video quality of the received multimedia at the back-end side of the transmission chain and (ii) the display at the end-user device. • Model the impact of the video content and video entertainment type to the true visual perception. • Modeling the influence of the video content to amount of impaired video artifacts, objectively measured, given the transmission channel conditions. • Modeling the influence of transmission errors to end-user device decoding functionality and hence visual quality. • Indicate cases the cause poor decoding performance.
Black box testing for TV systems Video TV & Video Audio RC Comm. PC based BBTesting platform software
Real case scenario ffmpeg reader –> PES Packetizer –> TS multiplexer Sirannon FFMPEG encoder Modulator YUV TS DVB-S/C/T AVI Hardware Attenuator TRILITHIC Demodulator ALITRONICA Live DVB-S/T/C Multi-channel TS Extract one video stream ffmpeg reader –> PES Packetizer –> TS multiplexer -> Basic Scheduler -> RTP/UDP/TCP Transmitter Back loop streaming Elementary stream Wireshark FFMPEG decoder PCAPtoTS PCAP TS YUV Generated files used for quality model evaluation
Feature-cluster driven VQA framework • VQA model design phase • Generating training test streams with realistic content and impaired artifacts. • Selecting set of objective measures for artifact-free video content and video artifacts. • Classify feature samples of the objective measures to corresponding video quality models. • VQA exploitation phase • Computing video feature samples and allocating them to the corresponding video quality model based on their cluster membership.
Training and test sequences used • Combined LIVE data base and SD VQEG sequences – in total 19 sequences • 13 training sequences randomly chosen • 6 test sequences randomly chosen • Different exact format • The first set has 4 different degradation levels based on variable bit-rate and the second has 5 fixed bit-rates. • Two different sequence sets with two independent MOS (ITU-R BT.500-11) obtained.
Feature-cluster driven VQA framework VQA Design Phase MOS1 objective measures QM1 EMOS1 MOS MOS2 Compute objective measures (features) Feature Reduction/ Selection Feature Sample Clustering Training video sequences QM2 EMOS2 MOSL Selected K-dimensional feature samples Objective feature samples QML EMOSL
List of considered objective measures • Measures for: • Contrast • Color • Brightness • Amount of motion: global and local • Spatial variance, • Homogeneity, correlation, mean, median • Spatiotemporal gradients • Blocking (intensity and occurrence), blurring, blocking • Other higher level measures such as freezing detection, packet-loss detection,…
Feature reduction/selection • Optional: Feed forward selection scheme.
Feature Clustering MOS MOS1 EMOS0 QM0 QM1 EMOS1 MOS2 Feature Sample Clustering QM2 EMOS2 MOSL Selected K-dimensional feature samples QML EMOSL
Feature-cluster driven VQA framework VQA Exploitation Phase wL Determine cluster membership w1 w0 EMOS0 QM0 Compute objective measures (features) EMOSf EMOS1 QM1 Feature samples Test video sequences EMOSL QML