A Low-Cost Multi-Sized HEVC Core Transform Using Time-Multiplexed DCT ‎Architectures

High Efficiency Video Coding (HEVC) is one of the latest coding standards targeting high-resolution video contents. Due to the high complexity of the existing hardware implementation, this paper presents the low-cost and efficient DCT architectures for HEVC, which are able to perform DCT operation of multiple transform sizes in a single unified architecture. Our objective is to reuse the hardware resources in a DCT architectures using configurable constant multipliers as well as reducing the hardware cost and trading off between hardware complexity and efficiency. We propose three different shift-and-add units with different hardware cost and throughput. The main advantage of the proposed architectures over the existing architectures is a lower hardware and it can also perform DCT transform of different transform units which is available in HEVC standard. The experimental results over 90-nm technology show that the proposed 2D-DCT architecture #1 archives the lowest hardware cost amongst the rest of the architectures with around 57% reduction in gate count, on average. The unfolded 2D-DCT architectures #2 and #3 offer the moderate reduction in gate count around 47%, on average, with a moderate throughput. Apart from architectures #1, #2, and #3, we also develop a reusable architecture by adding an extra (𝑁/2)-point DCT alongside the main DCT.