SEATTLE: Online retail giant Amazon has updated and improved its video-on-demand service, allowing US viewers to watch ad-free movies and TV programs instantly via their PCs, without the need for downloading.

Amazon Video on Demand is a revamped version of the Unbox service, launched two years ago.

Comments service director Roy Price: "The ability to watch content instantly without downloading first was among the most requested features of our customers, and now it's live."

The service, and a host of similar offerings from other firms, challenges US cable and satellite companies in providing programming on demand to the television set.

Amazon's VOD can be watched within a web browser, streamed directly on to Sony TVs equipped with an internet video link, through a TiVo DVR or an Xbox 360 games console.

Data sourced from Financial Times online; additional content by WARC staff