That wasn't me. I think it was user 'itsme' who wrote that on one of the first pages of this thread.
I'm not using the videomap from the chatserver. I connect to the chatserver, send hello, guest and it returns "fileno" and I use that to get "/mfc2/php/mobj.php?f={0}&s=chat{1}". This returns the entire list of broadcasters currently online and other various info about them in JSON. You do not have to stay connected to the chatserver while getting this list, but you can only get it once with that particular "fileno".
Code:
{"fileno":"112411765_1085803"}
{0} = fileno returned
{1} = chatserver number you connected to
I extract "nm", "uid" and "camserv". Then I do what you do as well. If "camserv" > 500 then substract 500. If "camserv" < 500 then I get the server from the videomap from the JS.
So far I have tested it with about 30 broadcasters and every time the videoserver was correct.