DCT is relatively expensive compared to just RLE, but keep in mind that JPEG has been standardized in early 1990s when 33Mhz CPUs were fast. Today a few multipl

DCT is relatively expensive compared to just RLE, but keep in mind that JPEG has been standardized in early 1990s when 33Mhz CPUs were fast. Today a few multiplications are nothing for CPUs. We have fast SIMD implementations. Nowadays Huffman is the bottleneck and could have been improved with tANS coding.