National Geographic has revealed that it too will drop HD DVD support in favour of Blu-ray releases from now on.
Distributed under the Warner umbrella along with New Line Home Entertainment, HBO Home Video and BBC Home Video, National Geographic has released only one high-def film so far, the aptly titled "Relentless Enemies", on both Blu-ray and HD DVD.
The Blu-ray version of "Relentless Enemies" is currently number 2411 in Amazon's Movies & TV rank whereas the HD DVD disc is a more lowly number 25,756.
A company spokesperson confirmed to HighDefDigest that they are not making an official press announcement, but that they will no longer release titles in the HD DVD format.
The next release due is "Sharkwater" which will launch on Blu-ray only in April.
BBC Home Video is now the only Warner-distributed company to remain format-neutral, a BBC spokesperson recently said they "will evaluate the marketplace before committing to one format".