Distributed video coding supporting hierarchical GOP structures with transmitted motion vectors

Kyung-Yeon Min,Ivan V Bajić,Donggyu Sim,Woong Lim,Junghak Nam

doi:10.1186/s13640-015-0068-3

Kyung-Yeon Min, Ivan V Bajić + Show 3 more

Open Access

https://doi.org/10.1186/s13640-015-0068-3

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Abstract

Abstract In this paper, we propose a new distributed video coding (DVC) method, with hierarchical group of picture (GOP) structure. Coding gain of DVC can be significantly improved by enlarging GOP size for slow-moving frames. The proposed DVC decoder estimates a side information (SI) frame and transmits motion vectors (MVs) of the SI to the proposed encoder. Using the received MVs from the decoder, the proposed encoder can generate a predicted SI (PSI), which is the same as the SI in the decoder, and estimate the quality of PSI with minimal computational complexity. The proposed method decides the best coding mode among key, Wyner-Ziv (WZ), and skip modes, by estimating rate-distortion costs. Based on the selected best coding mode, the best GOP size can be automatically determined. As the GOP size is adaptively decided depending on the SI quality, entropy and parity bits can be effectively consumed. Experimental results show that the proposed algorithm is around 0.80 dB better in Bjøntegaard delta (BD) bitrate than an existing conventional DVC system.

Highlights

As many portable multimedia devices have been developed, such as mobile phones, electronic pads, and laptops, many people enjoy using them to take videos, transmit them to friends or web-sites such as YouTube and Facebook, and in turn, view them
The conventional algorithm employs every other frame as the key frame, while the number of key frames are determined depending on group of picture (GOP) size
The side information (SI) frames are reconstructed based on an adaptive search range [24] and an low density parity check accumulate (LDPCA) channel coder with a matrix length of 6,336 [5]

Summary

Introduction

As many portable multimedia devices have been developed, such as mobile phones, electronic pads, and laptops, many people enjoy using them to take videos, transmit them to friends or web-sites such as YouTube and Facebook, and in turn, view them. Some conventional DVC algorithms are proposed to predict accuracies of SI frames on the encoder side and increase GOP size [13,14]. Since the purpose of DVC is to reduce computational complexity of the encoder, they should generate a predicted SI (PSI) with low delay, though an SI frame which is generated using several motion estimation algorithms and filters, for high quality of an SI on the decoder side.

Results

Conclusion