This is North America and Europe only.

IHS forecast 54 million worldwide including all territories.

Sold through, 34m PS4 and 20m XB1, right?

I'd say 35.5m PS4s and 18.5m XB1.

Wa talking about the IHS forecast, they predict 34m PS4 and 20m XB1 I think.

Correct. Those were the splits that IHS gave. 

49M is a little bit too low imo. I expect 50-53M.

Assuming PS4 remains pretty flat YoY from July through to December we're looking at ~ 10 million PS4s sold. So PS4 sell through LTD would be ~34 million. With Xb one LTD today that adds up to 47 million EOY PS4 (estimated) + July Xb one. Xb one sales might not be huge, but it will definitely sell a lot more than 2 million units between now and January.

If Xb one remains flat we will see another ~5.8 million sold for the remainder of the year. So we're looking at more like 53 million combined by the end of the year if there is no YoY growth for the second half of this year. 49 million would mean a 4 million 2H2015 decrease cf 2H2014. Even if Sony doesn't cut the PS4 price in key markets like the USA and Japan I can't see PS4 dropping YoY by that big of a number, especially since PS4 is up YoY for 1H2015. And if MS holds the Xb one price, I think Halo will prevent Xb one from falling too far short of holiday 2014. It is possible without price cuts for 2h2015 to be lower than 2H 2014, but I still expect PS4bone to crack 50 million this year.

Read my post. 

17m XB1
32m PS4
????????

That's seriusly TOO LOW...
I believe will be a bit less than 57 million shipped with 54-55 million sold...
PS4: 36 mln
XBO: 20.5 mln
(shipped, not sold)

EDIT: Ok, is not WW, is just EU+NA, ignore my post.

OK, so the estimation is for a low growth 2H2015. That suggests an expectation Sony will not cut the price of PS4. If Sony cut the price of PS4 then 54 million would be rather a low estimate. But if Sony releases a 1TB sku at $399 (and equivalent in other countries), then a small amount of YoY growth could be the result.