NBC Universal significantly deepened its relationship with Amazon’s digital video download service after a dispute with Apple over the pricing of television shows on iTunes.

The media conglomerate, part of General Electric, said yesterday that Amazon had agreed to give it something that Apple would not: greater flexibility in the pricing and packaging of video downloads. As a result, NBC Universal said it had agreed to sell a wide variety of television programming on Amazon’s fledgling Unbox download service, including the drama “Heroes” and the comedies “The Office” and “30 Rock.” Episodes will be available on Unbox the day after they are shown.

While Amazon is still working to determine pricing, Unbox typically charges more for newer releases than for older ones. Unbox also gives consumers more options, including whether to rent a movie for $3.99 or buy a download for $14.99. Amazon agreed to offer promotions, including a 30 percent discount when buying full seasons of television shows.

Apple sells episodes of television shows for a flat $1.99, with movies priced at $9.99.

Last week, NBC Universal became the first television and movie company to publicly challenge Apple’s pricing as too low, saying it would not renew its contract with iTunes without a change in its pricing. Apple retaliated by saying it would not add new episodes of NBC shows to the iTunes inventory.

NBC Universal’s decision to be a partner with an Apple rival could embolden other media companies to do the same. The News Corporation in particular has been grumbling about Apple’s prices. And Amazon has now shown that it is waiting with open arms.

“Amazon is a company that understands the value we provide as content owners to its business,” said Jean-Briac Perrette, president of NBC Universal Digital Distribution.

Amazon hopes NBC Universal’s inventory will give Unbox a much-needed boost. Unveiled in September 2006, the service is a distant competitor to iTunes and has suffered from scattered service problems, including lengthy waits for downloads.

While Amazon has solved many of the problems, Unbox is still limited in one important aspect: It is not compatible with Apple’s iPods, which are by far the most popular portable video players.

Unbox allows consumers to rent or buy video for viewing on a personal computer or certain portable video players. Unbox can also deliver video directly to TV sets through TiVo devices.

In addition to new episodes of returning series, NBC Universal said it would allow Unbox customers to download free — in advance of their network premieres — the pilot episodes of new series, including a “Bionic Woman” remake and “Journeyman,” about a man who travels through time to help people in trouble.

NBC Universal has long offered library movies like “Psycho” and “Animal House” on Unbox and later this year will begin offering newer releases like the comedies “Knocked Up” and “Evan Almighty.”