Apple is planning to unveil a renewed focus on the living room with an upgraded Apple TV set-top box that can stream 4K video and highlight live television content such as news and sports, according to people familiar with the matter.

The updated box, to be revealed alongside new iPhone and Apple Watch models at an event in September, will run a faster processor capable of streaming the higher-resolution 4K content, said the people, who asked not to be identified because the plans aren't yet public. Apple is also testing an updated version of its TV app, which first launched in 2016, that can aggregate programming from apps that already offer live streaming.

Apple is seeking to revive its video ambitions with the new product. Apple TV trails devices from Roku, Amazon and Google in the US set-top box market share with only 15 per cent as of the end of March, according to a survey this month from Parks Associates. Apple CFO Luca Maestri told Bloomberg earlier this year that Apple TV sales had declined year-over-year in the 2016 holiday quarter. The iPhone maker has also lagged behind companies such as Amazon and Netflix in developing scripted shows and other video content.

In order to view 4K video, users will need to attach the updated Apple TV to a screen capable of showing the higher-resolution footage. Many recent TV models from Sony, LG and Samsung offer 4K output. The new box will also be able to play content optimised for TVs capable of playing High Dynamic Range (HDR) video, which produces more accurate colours and a brighter picture. In February, Bloomberg reported that a 4K Apple TV model had gone into testing. An Apple spokeswoman declined to comment.

Apple, the world's most valuable company, relies on the iPhone for more than half of its annual revenue. Its services business, which includes the App Store and Apple Music, is its fastest growing unit and generated 16 per cent of the company's sales in the most recent quarter.

At its developers conference in June, Apple CEO Tim Cook said "you'll be hearing a lot more about tvOS later this year," referring to the Apple TV's operating system. Apple last updated the Apple TV box in 2015 with a new remote control, an App Store and support from its Siri voice assistant. It added new software features, including the TV app, last year.

In order to play 4K and HDR content, Apple will need deals with content makers that can provide video in those formats. The technology giant has begun discussions with movie studios about supplying 4K versions of movies via iTunes, according to people familiar with the talks. The company has also discussed its 4K video ambitions with content companies that already have apps on Apple TV, another person said. Popular video apps on the Apple TV that support 4K on other platforms include Vevo and Netflix.

The new Apple TV will come as part of a major product blitz planned by the iPhone maker for this holiday season. The company is planning three new iPhone models, including a premium model that includes a 3D facial recognition sensor for unlocking the phone, as well as a new Apple Watch that can connect to LTE mobile data networks, Bloomberg has reported. Earlier this year, Apple rolled out upgraded iPad models with improved screens and Macs with faster processors. Apple will end the calendar year with the release of a new iMac desktop geared toward professionals and the HomePod Siri-controlled speaker, the company said in June.

Bloomberg