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Wavelet-Based VBR Video Traffic Smoothing. Dejian Ye, J. Cam Barker, Zixiang Xiong, and Wenwu Zhu IEEE Trans. Multimedia, Aug. 2004. Outline. VBR video transmission Smoothing algorithms MVBA (minimum variance) MCBA (minimum changes) PCRTT (piecewise constant-rate)
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Wavelet-Based VBR Video Traffic Smoothing Dejian Ye, J. Cam Barker, Zixiang Xiong, and Wenwu Zhu IEEE Trans. Multimedia, Aug. 2004
Outline • VBR video transmission • Smoothing algorithms • MVBA (minimum variance) • MCBA (minimum changes) • PCRTT (piecewise constant-rate) • WTS (wavelet-based traffic smoothing) • Smoothing at multiple resolution • Low computational complexity • Performance evaluation
VBR: aggregated traffic flow From server to client: link 3 link 2 link 1
PCRTT (piecewise constant-rate transmission and transport) • Divide the video stream into segments to create a transmission schedule. • Each segment corresponds to one rate in the transmission schedule. (set the transmission rate to the average frame size for each segment) • Raise the transmission schedule to avoid client buffer underflow. • Force a rate change after every segment.
PCRTT L Seg 1 Seg 2 Seg 3 Seg 4 Seg 5
WTS • PCRTT works well for both single and aggregated flows. • WTS is based on PCRTT. • Motivations: • Smooth aggregated flows. (?) • Client buffers can be heterogeneous. (difficult to schedule transmission)
uj+2, 4k+3 uj+2, 4k+2 uj+1, 2k Binary tree Tmax Has enough buffer?
Buffer size: the min #frames between two adjacent rate changes