Interesting problem.
On Windows XP, running the last version of Chrome that works on XP (v49 or so), VDH works great on
pornhub.com downloading mp4 and webm.
pornhubpremium (their pay service) doesn't work in that old of a version of chrome at all, so I boot up Windows 7.
VDH in the latest version of Chrome refuses to capture anything off either pornhub or pornhubpremium.
I think it's something to do with HTML5 which the older version of Chrome doesn't support, so it reverts to Flash which work more reliably.
Anyhow, VDH refuses to capture anything other than 678 byte files, which obviously aren't the clips. Companion App doesn't help.
I have to use competing stream capture plugins and even those only capture the stream about 50% of the time, requiring F5 after F5 after F5.
I understand to debug this may require buying a subscription to pornhubpremium (the links appear to work differently than regular pornhub). But it's a one week $1 trial. Just be sure to cancel the credit card or subscription.