Cablevision stepped up the battle to attract high-definition customers on Friday, saying it would have the capability to carry more than 500 channels of HD programming by the end of this year.

In a surprising move, Voom's 15 HD channels would become Part of Cablevision's offering next Wednesday, making 40 networks available to the company's customers. Voom is owned by DISH Network.

"The VOOM channels represent the pinnacle of high-definition and we are pleased to extend our leadership position in this important category through the introduction of these exciting services," Cablevision senior vice president John Trierweiler said.

Networks run by Voom include HDNews, Animania, GamePlay HD, and World Cinema, among others.

The race for HD is becoming fast and furious, with consumers opting for high-definition televisions in increasing numbers. Verizon has promised to focus heavily on HD in its FiOS product, and DirecTV says it will have 150 channels in high-def by the end of the year.

Comcast has lagged behind other operators, with a fairly small HD offering. However, by the end of the year it claims it will offer some 400 "choices," doubling in the following year. This does not mean channels, however; the company defines choices as both on-demand and broadcast channels combined.