SNR scalability by transform coefficient refinement for block-based video coding

Various techniques for SNR scalability in hybrid block-based video coding exist in the literature and in different standards. A new approach based on transform coefficient refinement is proposed in this article. The coefficient difference is computed after quantization, subsequently entropy-encoded, and transmitted for reconstruction of a high-quality layer at the decoder. The approach achieves in most cases only a moderate increase in bit rate as compared to other schemes. The bit rate of our two-layer framework converges towards the rate of a single-layer system as the quality gap between both layers increases. The gains come at the cost of increased computational complexity and memory requirements.