How do 720p Divx movies compare to Bluray /Hd Dvd?

Question

I have some Planet Earth doccumentaries in 720p ( arund 2.2 gbs for 40mins ) and the picture is very good but is the proper Hd encoding from Hd Dvd a lot better ?

Answer 1

In theory they will be better (after all you are talking a higher pixel density), but how much -- if any -- difference you actually see will depend on a number of factors.

As an aside, a precondition for the comparison is the display must be able to show the difference (e.g. a 1080p display rather than a 720p)

In terms of factors to consider the codecs used will determine compression and this will have an impact on the picture quality. Divx is a form of Mpeg 4, while HD DVD is usually VC-1. While more compression is not necessarily worse than less, in this case I think VC-i is liable to result in higher picture quality.

The colour space will be different, so HD DVD or Blu-ray disks might look superior due to more colours and greater saturation.

Another prime consideration is where you sit relative to the screen. If you sit far enough back any resolution difference (720p vs 1080p) would not be visible (it's simply a case of visual acuity). It may help to consider that the picture on a 720p and 1080p under 50" (and even that is debatable) viewed from 8-10" away are indistinguishable.

Also consider that contrast ratio, colour saturation and colour accuracy are all more impoprtant than resolution as determinants of picture quality.

That all said, given that compression, colour space and resolution all favour HD DVD, unless you are sitting far enough away HD DVD will look better. But only you can decide how to judge the difference. Some viewers are more picky than others.

Bottom line .. HD DVD will most likely look visibly (at close viewing distances) superior to Divx ... but it certainly won't be "night and day".