Haha, hilarious… 
Even slow small battery powered single core ARM computer running Linux can do DoP packing at DSD512 without hiccups. I don’t know what he uses…
The non-2s poly-sinc filters are single stage, going in one step from 44.1k to for example 22.5792 MHz (DSD512), not cascaded. closed-form with about 8M taps at 22.5792 MHz is a about 360 ms long.
I agree the pseudo numbers about taps are meaningless, but for some strange reason he/Chord wants to brag about number of taps like it would mean anything. I’ve said many times, number of taps are meaningless marketing.
Maybe he should look into modern CPUs and GPUs that HQPlayer can utilize in parallel. I’m not going to repeat the specs, but I doubt his DACs can reach the memory bandwidths of Nvidia GPUs exceeding 480 gigabytes/sec. Or clock speeds of latest Intel CPUs running at over 4 GHz. Latest Nvidia GPUs have 12 billion transistors…
In addition, the DSP system in HQPlayer is not run synchronously with the input data, so it can go back and redo the calculations multiple times as necessary to arrive at better solution, based on running analysis of the output data. And still keep on producing DSD512 (or DSD1024) output.
P.S. About the 30 years comment, algorithms in HQPlayer have taken me soon 20 years to refine. Next year is 20th birthday of HQPlayer.