Apple Inc. (AAPL) - Get Report was once the king of the online video market, but in just a few years, it's lost its tremendous lead.

By contrast, Amazon.com Inc. (AMZN) - Get Report and Comcast Corp. (CMCSA) - Get Report have seen huge gains in the market, which involves sales and rentals of movies. Apple controlled more than 50% of the digital movie business as recently as 2012, but that share has since dropped to between 20% to 35%, the Wall Street Journal reports, citing sources familiar with the situation. Amazon, which offers movie rentals and purchases through its website, has seen its share increase to about 20%, while Comcast, which makes those services available on its set-top boxes, now holds a 15% share.

Comcast has been renting movies via its set-top boxes since 2013 and recently rolled out the X1, its next generation video platform for cable boxes and mobile devices. Amazon, meanwhile, has been aggressively moving into digital video, making its video platform available on most connected TVs, which has given it exposure to consumers who wouldn't otherwise consume those kinds of content, said Dan Cryan, senior director of broadband media for IHS Markit.

Although Apple has lost its lead, a company spokesperson told the Journal that, over the past year, movie purchases and rentals on iTunes hit their highest level in more than a decade. Representatives from Apple weren't immediately able to comment.

"The overall market of the movie rental and purchase business is growing, but consumers aren't doing more of this as time goes by," Cryan said. "Within that context, the iTunes movie business is also growing, but it's taking on a smaller share of the growing pie."

Apple launched iTunes in 2003 as a platform for downloading music, before it added TV shows and movies for purchase in 2005 and, later, rentals in 2006. iTunes quickly became the blueprint for tech companies who wanted a hand in distributing music, movies and books on the internet, but it has struggled in recent years as a host of other music and video streaming services have emerged, especially subscription streaming services such as Netflix Inc. (NFLX) - Get Report and Amazon Prime Video.

"There's a growing amount of opportunities in the way that there wasn't when iTunes first launched," Cryan explained.

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Editors' pick: Originally published July 10.

In 2016, video-on-demand movie rental revenue in the U.S. slid 4% to $1.8 billion, according to PricewaterhouseCoopers, but digital movie purchase revenue grew 21% to $3.5 billion. In response, Apple has focused on giving consumers access to services such as Netflix and HBO, where it takes a 15% cut of the subscriptions sold via the App Store and Apple TV, the Journal noted.

Apple's share of the video on demand rental market is smaller than its share of the online movie purchase market, which is between 45% to 50%, Cryan said, citing a range of industry conversations with service providers and content suppliers.

iTunes is still the second-largest unit by revenue of Apple's Services business behind the App Store, according to research from Bernstein. iTunes comprises 17% of Apple's total Services business, generating an estimated $4.1 billion in revenue out of total Services revenue of about $24 billion in 2016. Apple has reiterated lofty goals for its Services business, expecting it to double in revenue by 2020.

So Apple customers are still renting and buying movies and TV shows on iTunes, but its competitors' businesses are growing faster. Apple could also persuade consumers to purchase more video content if it can gain access to early releases. The tech giant is said to be in talks with Hollywood studios, including 21st Century Fox (FOX) - Get Report , Time Warner's (TWX) Warner Bros. and Comcast's (CMCSA) - Get Report Universal Pictures, to secure home-video rentals of movies two weeks after they open in theaters, according to Bloomberg. Movies would cost anywhere between $25 and $50 under that model, but as with most Apple products, fans are usually willing to pay a premium for the company's services.

More and more Hollywood studios are flirting with the idea of releasing films online as soon as 17 days after they open in theaters. MoffettNathanson analyst Robert Fishman estimated that premium video-on-demand could add as much as $1.8 billion to studios' bottom lines, Variety reports.

Apple is known to have good relationships with Hollywood studios, in large part via Apple executive Jimmy Iovine, and has gotten dibs on video-on-demand titles before other providers for a long time. Gaining early access to the premium video-on-demand space would allow iTunes to potentially corner the market on exclusive movie releases, allowing Apple to differentiate itself from the likes of Amazon, Comcast, Netflix and other video providers.

Ultimately, Apple will only explore premium video-on-demand if it serves to benefit existing Apple users, which is in line with its strategy historically, Cryan said.

"If the answer is yes, you can expect them to launch it," Cryan noted. "The alternative would be more and better subscription services on Apple TV."

Shares of Apple were increasing 1.1% to $145.81 on Monday afternoon.