Interframe Encoder. Interframe Decoder. X i. X i ’. Standard codec. X’ i-1. Interframe Video Compression. Interframe predictive coding for compression Encoder is 5-10 times more complex than decoder. X i-1 ’. Interframe Decoder. Intraframe Encoder. X i. X i ’. Side Information.
Interframe Video Compression
Low-complexity Video Coding
Wyner-Ziv Coding Lossy source coding with decoder side information
Imagine dependence channel between source and side-info. WZ coding
= sending parity symbols to correct errors in the dependence channel.
to current frame? Hash-Aided Motion Estimation
dependence channel? Hash-Aided Rate Control
Project motivated by Wyner-Ziv video codec architecture
described in [Aaron et al., VCIP ’04, ICIP ’03].
B=00110110received from encoder
as helper information
Hash-aided Motion Estimation
Projecting onto low frequency patterns is equivalent to finding the low-frequency DCT
coefficients. Similar looking blocks have almost equal low-frequency DCT coefficients
and produce almost similar hashes.
Foreman QCIF Frames 301 to 350
Error between current frame and side information
With previous frame
As side info
With hash-aided motion
estimation with excess
bit-rate = 0.14 bpp
small hash store.
between MSE of MC prediction and parity bitrate, which the
encoder needs to transmit.
as a function of MSE of MC prediction.
Avg Hash bitrate
= 0.175 bpp
Avg WZ bitrate
= 1.27 bpp
improve the quality of the side-information at very low bit-rate
overhead. This reduces the overall Wyner-Ziv bit-rate.
performed at the encoder. This enables the encoder to control
the Wyner-Ziv bit-rate depending upon the quality of the
Frames decoded conditionally
Side Info: previous decoded frame(s)
+ Helper information from encoder