VLSI Friendly Framework for Scalable Video Coding based on Compressed Sensing

This paper presents a new VLSI friendly framework for scalable video coding based on Compressed Sensing (CS). It achieves scalability through 3-Dimensional Discrete Wavelet Transform (3-D DWT) and better compression ratio by exploiting the inherent sparsity of the high-frequency wavelet sub-bands through CS. By using 3-D DWT and a proposed adaptive measurement scheme called AMS at the encoder, one can succeed in improving the compression ratio and reducing the complexity of the decoder. The proposed video codec uses only 7% of the total number of multipliers needed in a conventional CS-based video coding system. A codebook of Bernoulli matrices with different sizes corresponding to the predefined sparsity levels is maintained at both the encoder and the decoder. Based on the calculated l0-norm of the input vector, one of the sixteen possible Bernoulli matrices will be selected for taking the CS measurements and its index will be transmitted along with the measurements. Based on this index, the corresponding Bernoulli matrix has been used in CS reconstruction algorithm to get back the high-frequency wavelet sub-bands at the decoder. At the decoder, a new Enhanced Approximate Message Passing (EAMP) algorithm has been proposed to reconstruct the wavelet coefficients and apply the inverse wavelet transform for restoring back the video frames. Simulation results have established the superiority of the proposed framework over the existing schemes and have increased its suitability for VLSI implementation. Moreover, the coded video is found to be scalable with an increase in a number of levels of wavelet decomposition.