Multi-Path Transport of FGS Video Jian Zhou, Huai-Rong Shao, Chia Shen and Ming-Ting Sun ICME 2003

Outline Introduction Introduction Multi-path Transport Multi-path Transport Multiple Description Coding Multiple Description Coding FGS transport with Multi-paths FGS transport with Multi-paths Statistics of FGS streams Statistics of FGS streams Splitting Mechanism Splitting Mechanism Simulation Result Simulation Result

Introduction FGS can dynamically adapt to available bandwidth obtained by some end-to-end network probing and estimation component. FGS can dynamically adapt to available bandwidth obtained by some end-to-end network probing and estimation component. However, the network estimation components usually cannot reflect instantaneous congestion effectively However, the network estimation components usually cannot reflect instantaneous congestion effectively LOST PACKETS !! LOST PACKETS !!

Multi-path Transport Multi-path transport of streaming video Multi-path transport of streaming video

Multi-path Transport (cont.) Overlay network technologies Overlay network technologies CDN (content Distribution Network) CDN (content Distribution Network) Pear-to-pear network Pear-to-pear network Ad-hoc network Ad-hoc network Wireless network Wireless network MIMO (multiple input and multiple output) MIMO (multiple input and multiple output)

Multiple Description Coding How do we deal with packet loss How do we deal with packet loss Request a retransmission. Request a retransmission. Good for loss-less transmission. Good for loss-less transmission. Not feasible for real time data such as voice and video. Not feasible for real time data such as voice and video. Reconstruct from other packets. Reconstruct from other packets. Requires adding redundancy to packets (coding). Requires adding redundancy to packets (coding). Advantage: Graceful degradation of output quality when packet losses increase. Advantage: Graceful degradation of output quality when packet losses increase. Multiple Description Coding.

Multiple Description Coding (cont.) Dependency between descriptions Dependency between descriptions Packetization Packetization Error Concealment and Error Propagation Error Concealment and Error Propagation Frame and Macroblock interleaving Frame and Macroblock interleaving This paper proposed a scheme to transmit an FGS stream over the multiple channels This paper proposed a scheme to transmit an FGS stream over the multiple channels

FGS streams Statistics of FGS streams Statistics of FGS streams

FGS streams (cont.) For the base-layer and some of the enhancement layer (EL),such as EL1 and EL2, the bit-rate are relatively low. For the base-layer and some of the enhancement layer (EL),such as EL1 and EL2, the bit-rate are relatively low. Use FEC code to protect Use FEC code to protect Use FEC code to protect high bit-rate EL may not be effective Use FEC code to protect high bit-rate EL may not be effective The more bandwidth required from the applications, the more difficult for the network to support QoS for it. The more bandwidth required from the applications, the more difficult for the network to support QoS for it.

Multi-path transport for FGS Two extreme cases: Two extreme cases: To duplicate the original video into each available channel To duplicate the original video into each available channel The bandwidth of each channel is not sufficient The bandwidth of each channel is not sufficient To Segment the original video into non- overlapping packets To Segment the original video into non- overlapping packets If packet lost occurs, the information will not be reconstructed If packet lost occurs, the information will not be reconstructed

Proposed Scheme Base-layer and certain ELs with lower bit- rate Base-layer and certain ELs with lower bit- rate protected using FEC schemes protected using FEC schemes Copy to every available path Copy to every available path ELs with higher bit-rate ELs with higher bit-rate Using Splitting Mechanism to convert the bitstream into multiple descriptions Using Splitting Mechanism to convert the bitstream into multiple descriptions

Splitting Mechanism A simple method is to distributes the “ 1 ” bits evenly into the multiple descriptions A simple method is to distributes the “ 1 ” bits evenly into the multiple descriptions001…………… …………… ……………110

Splitting Mechanism (cont.) Another scheme is to distribute the “ 1 ” bits according to their importance Another scheme is to distribute the “ 1 ” bits according to their importance ……………110 important001…………… …………… Duplicate

Cost Function We have four distribution if there are two path available We have four distribution if there are two path available Previous stateCurrent state

Simulation Model Using Two-state Markov Channel Model Using Two-state Markov Channel Model p1 : the transition probability of the channel to change from the “ Good ” state to the “ Bad ” state p1 : the transition probability of the channel to change from the “ Good ” state to the “ Bad ” state p2 : the probability that the channel will remain in the ” Bad ” state p2 : the probability that the channel will remain in the ” Bad ” state P on and P off : the packet loss rate in “ Good ” and “ Bad ” state P on and P off : the packet loss rate in “ Good ” and “ Bad ” state

Simulation Result Sequence : “ News ”, QCIF format Sequence : “ News ”, QCIF format Only I and P frame Only I and P frame 4 Enhancement Layer 4 Enhancement Layer Packet size: 500 byte Packet size: 500 byte

Simulation Result