I'm someone with an intermediate level of coding experience, but I have no idea what exactly is meant here by "encoding complexity". What's the difference betw

I'm someone with an intermediate level of coding experience, but I have no idea what exactly is meant here by "encoding complexity". What's the difference between 3X and 100X? What's the encoding complexity of h.264 vs MPEG-2? Is it just saying that they're OK with the encoding algorithm taking 100 times as much processing power or taking 100 times as many processor cycles to compress a given data stream?