Video Compression for Lossy Packet Networks With Mode

Video Compression for Lossy Packet Networks With Mode Switching and a Dual-Frame Buffer Author: Athanasios Leontaris and Pamela C. Cosman Source: IEEE Transactions on Image Processing, Vol. 13, Issue 7, July 2004, pp. 885 -897 Speaker: Kai-Jung Shih Date: 2004. 7. 19

About This Paper n Mode switching: n n Inter-frame coding vs. Intra-frame coding. Dual-frame buffer: n n Previous frame From the more distant past frame Kai-Jung Shih 2

Video Compression n Macro-Block(MB) n n Intra-frame coding: n n MB 1, MB 2, …, MB 9 May be encoded in intra- or intermode May be weighted Higher error resilience MB 7 of Framen-1 Inter-frame coding: n n n Higher coding(compression) efficiency MB in current frame is predicted from previous frame. Motion Vector(MV): v(x, y) Kai-Jung Shih 3

Error Propagation n n A single error in a past frame may corrupt all subsequent frames if inter-coding is used repeatedly. Can only stopped by intra-coded MB. Kai-Jung Shih 4

ROPE(Recursive Optimal Per-pixel Estimate) n n Used for mode decision in hybrid video coder operating over packet erasure channels Groups-of-block(GOB) n n n {MBi(frame 1), …, MBi (framen)} Carried in a separate packet. Error concealment GOB 7 Kai-Jung Shih 5

Error Concealment of ROPE GOB 8 (4, 3)(8, 6) (1, 1) intra GOB 1 GOB 4 (4, 3) n n n Case 1: median of MV of three nearest MBs in previous GOB. Case 2: MV=(0, 0), if previous GOB is also lost. Case 3: MV=(0, 0), if three nearest MBs were all intra-coded. Kai-Jung Shih 6

Proposed Method n n Short-term(n-1) and Long-term(n-k) frame reference Each MB can be encoded in three type: n n n Intra-coding Inter-coding using shortterm buffer Inter-coding using Longterm buffer Kai-Jung Shih 7

Jump Vs. Continuous Updating Kai-Jung Shih 8

PSNR performance versus bit rate for GOB error rate p = 10%. Kai-Jung Shih 9

PSNR performance versus GOB error rate. Kai-Jung Shih 10

Conclusions n (2003) “Video Compression with Intra/Inter Mode Switching and a Dual Frame Buffer, ” in Proc. IEEE Data Compression Conf. n n n PSNR performance versus bit rate for PSNR performance versus GOB error rate (2004) “Video Compress for Lossy Packet Networks With Mode Switching and a Dual. Frame Buffer” n n Distortion estimation comparison PSNR performance versus bit rate PSNR performance versus GOB error rate Rate distortion optimization of MV selection Kai-Jung Shih 11