What is the difference between Digital HD and DVD

As pointed out above ^^^^

Blu-ray runs at a higher resolution and due to larger storage on the Discs, they can also hold more Extras.

In regards to Digital HD, i think you are referring to the ability you get with some DVD/Blu-ray Purchases to have a Free Digital Copy, you will have a CODE usually with the DVD/Blu-ray and they give you a website to then download a Copy of the Movie that you can use on a Computer or other Medium, Tablet/Phone and some DVD/Blu-ray players.

The Digital Downloads usually come as just the movie alone and most commonly were available in 720P and 1080P Formats.

Digital HD is an option when making iTunes movie purchases, for an additional cost. The resolution is far superior to Standard Definition (DVD equivalent), about five times as many pixels on the screen. iTunes movies often come with a menu and extras, like you find on a disc release, marketed as 'iTunes Extras'.

My understanding for resolution is that there is no noticeable difference on most 32 inch TVs be it bd , hd or dvd. 

The combination of screen size, distance and pixel resolution determines whether there's a noticeable difference or not. Check out the coloured 'optimal viewing distance' chart on this page. The lilac (1080p) zone represents HD movies.

Any closer than 11' to a 32" TV, and HD is better than DVD for you. These days, however, most screens sold are larger than this, which is another nail in the coffin for DVD.

I've got to get some use out of my Xbox One S (silly impulsive purchase) so, as long as it's got the extras, I'm going for 4K.

 hox Nice chart. Thanks for posting.

Ah- Spam above last post.

Itunes is selling AC for 9.99 only currently. I am still thinking should I purchase one. I was planning to buy the blu ray if price drops.

Guys do you know any content differences between Blu ray and the iTunes releases?