Amazon.com Inc. is talking with major media companies about offering unlimited views of older TV shows and movies online, as it struggles to stay relevant to consumers flocking to Apple Inc.'s iTunes a la carte store and Netflix Inc.'s subscription DVD plan. Amazon has approached several companies, including Viacom Inc., Time Warner Inc., and Sony Corp., three people familiar with the matter said Tuesday. They requested anonymity because the talks are ongoing. The talks are at an early stage and focus on offering TV shows and movies that have already been available on home video, according to one person. Amazon intends to link the service to its Amazon Prime membership, a $79 per year plan that gives customers discounted shipping costs.