Video Coding with Optimal Inter/Intra-Mode Switching for Packet Loss Resilience Rui Zhang, Shankar L. Regunathan, and Kenneth Rose IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2000

Introduction to intra/inter mode switching Intra-coding? Inter-coding? Bit rate issue Robustness issue Balance in intra/inter-coding in previous work Periodically intra-coding “ Content-adaptive ” Threshold

Contribution Propose Recursive Optimal Per-pixel Estimate of decoder distribution (ROPE) Optimally estimate at encoder the overall distortion of a decoder Performance of RD-based mode switching is substantially improved by using precise distortion estimation

Expected decoder distortion per pixel Expected distortion for ith pixel of nth frame: encoderdecoder Internet fn ^ fn ~ fn

Expected decoder distortion per pixel: possibility tree Packet loss rate: p Received correctly Received incorrectly p 1-p Previous packet received correctly Previous packet received incorrectly 1-p p Case 1: 1-p Case 2: p(1-p) Case 3: p^2 Specified by: 1.Initial negotiation 2.Calculated from information provided by the transmission protocol (Ex: RTCP)

Expected decoder distortion (intra-coded) Case 1: no need to calculate Case 2: median of the nearest 3 GOBs Case 3: set motion vector estimation to zero encoderdecoder Internet fn ^ fn ~ fn

Expected decoder distortion (intra-coded) encoderdecoder Internet fn ^ fn ~ fn

Expected decoder distortion (inter-coded) Case 1: Case 2: median of the nearest 3 GOBs Case 3: set motion vector estimation to zero

Expected decoder distortion (inter-coded) encoderdecoder Internet fn ^ fn ~ fn

Simulation 1: PSNR & frame number Carphone r = 100 kb/s f = 10 f/s, p = 10% Salesman r = 300 kb/s f = 30 f/s, p = 10%

Simulation 2: PSNR & packet loss rate (incorporated with rate- distortion framework) Carphone r = 100 kb/s f = 10 f/s, Salesman r = 300 kb/s f = 30 f/s,

Conclusion Propose a method for optimal intra/inter-mode switching Incorporate within an RD framework to optimally select the coding mode