@rantanplan, thanks but I already know what you explain here.
So I always use exteplayer3 by default (setting lile this in ServiceApp) for all my IPTV streams so I just report that the one given here is the the only one that doesn't work. I have to change its definition to 4097 to have it working.
And I know that Duo4K is not HiSi based STB, but I was finding interesting to test it too on my STB and report the result here.