×
You will be redirected back to your article in seconds

How Netflix Delivers Better-Looking Downloads Without Eating Up All Your Phone Storage

When Netflix introduced the ability to download content onto mobile devices for offline viewing earlier this week, it also debuted a few technical tweaks to make sure that those downloaded episodes of “Black Mirror” won’t eat up all of your phone’s storage. Eventually, Netflix wants to use the same technologies to optimize streaming to mobile devices as well.

One of the biggest differences between shows you download and shows you stream on Netflix is the video format, or codec, the company is using. For streaming, Netflix has been using H.264/AVC almost exclusively. However, users who download Netflix shows to most Android devices instead receive content encoded with VP9 — an open source video codec developed by Google that uses a bunch of advanced encoding tricks to deliver the same video quality with significantly less data, or a better video qualities with the same amount of data.

The problem with VP9 is that it isn’t supported by everyone in the industry. Given Google’s backing, it obviously runs on Android and in the company’s Chrome browser, and a growing number of consumer electronics devices are capable of playing VP9 videos as well. iPhones, however, can’t and Apple has given no indication that it plans to support VP9 any time soon.

That’s why Netflix is also encoding its downloadable videos with a different flavor of H.264/AVC, which is also known as a different profile. (For the technically inclined: Netflix’s streams are encoded with H.264/AVC Main, whereas its downloads come in H.264/AVC High. The company shared more details on its tech blog this week.) This isn’t quite as effective as using VP9, but still allows Netflix to shave off some bits.

But Netflix didn’t just switch its codecs. The company’s encoding team also realized that different scenes in different movies require vastly different amounts of data. An action scene with a lot of visual noise contains a lot more visual information than a scenic shot of a blue sky, and animated movies in general are much easier to encode than live-action films.

Netflix first started to account for these visual differences last year, when it began to tweak its encoding settings for each and every title — an approach that helped the company to deliver better-looking streams to users with slower internet connections while saving up to 20% of data.

For its new download option, the company is taking the idea one step further: Instead of changing these settings per title, Netflix is cutting each and every video into one-to-three-minute-long chunks. Computers then analyze the visual complexity of each and every of these clips, and encode with settings that are optimized for its visual complexity.

The resulting potential bandwidth savings are significant: Compared to the encoding tech Netflix uses for streaming, using this chunking method in combination with the new VP9 codec saves around 36% of bandwidth on average for videos that look the same to the human eye.

Videos encoded with H.264/AVC High still use up to 19% less bandwidth on average. In other words: iPhone users could theoretically be able to save five episodes of “Black Mirror” with the same amount of space on their phone that would have been occupied by four episodes with Netflix’s existing technology.

To be fair, the actual storage savings may not be as significant in every case. That’s because optimizing encoding of videos isn’t just about saving space on your phone, or making sure you don’t go above your monthly data cap. The same tech is also being used by Netflix to optimize the quality of videos prepared for download, meaning that Netflix delivers better-looking videos without eating up more of your phone’s storage.

The potential to improve video quality is also a big reason why Netflix plans to bring both chunk-based encoding as well as new encoders to mobile streaming in the coming months as well.

Correction: 12/4: An original version of this article primarily focused on storage savings of the new encoding approach. It was updated to reflect the fact that Netflix also uses the technology to improve video quality.

More Digital

  • Kelly Abcarian - Nielsen

    Nielsen Forms Addressable TV Ad Group After Buying Sorenson Media's Assets for $11.25 Million

    Nielsen thinks it has the pieces in place to finally drive up the scale of addressable TV advertising, targeted based on a television household’s profile the way internet ads have been served for years. The media-measurement firm has formed Nielsen Advanced Video Advertising, a new group focusing on developing addressable advertising initially for internet-connected smart [...]

  • Hooq Sets up Filmmakers Guild For

    Hooq Sets up Filmmakers Guild For Second Year of Pilots

    Asian video streaming platform, Hooq is to air five pilot episodes that have emerged from its Filmmakers Guild. The most successful is guaranteed to be produced as a full series and streamed on the platform. Five original selected screenplays were each awarded $30,000 to be made as pilots, which now air from March 1. The [...]

  • Fortnite Battle Royale

    Epic Pulls 'Fortnite' Ads From YouTube After Child Predator Controversy

    Epic Games is no longer running “Fortnite” pre-roll ads on YouTube after it was discovered they were playing on videos alleged predators used to exploit children, according to The Verge. The developer has paused all of its pre-roll advertising, which plays before a video starts on the streaming platform, a spokesperson said. It also reached [...]

  • New Video Shows Off Vive Cosmos

    New Video Shows Off Vive Cosmos VR Controllers

    There’s still much to be learned about HTC’s Vive Cosmos — like release date, specs, and price — but Wednesday the company released a short teaser video giving a slightly better glimpse of the controllers in action. The new controllers look a bit like rival VR headset Oculus Rift’s Touch controller, though reversed in some [...]

  • YouTube logo

    Disney Reportedly Pulls YouTube Ads Over Child-Exploitation Controversy

    YouTube is facing yet another big advertiser backlash, with Disney, Epic Games and McDonald’s among the marketers said to have pulled their ad spending after the Google-owned video platform was accused of facilitating what a critic described as a “soft-core pedophilia ring.” Vlogger Matt Watson, in a Feb. 17 video on his YouTube channel MattsWhatItIs, [...]

  • Samsung Galaxy S10, Galaxy S10+ Unveiled

    Samsung Announces Galaxy S10, Galaxy S10+ Phones

    Samsung officially announced its new flagship phones, the Galaxy S10 and its larger sibling, Galaxy S10+, at its Unpacked press event in San Francisco on Wednesday morning. The new phone features a punch-hole cut-out for its front-facing camera, which allowed the company to use an edge-to-edge screen design without the notch found on the latest [...]

  • Samsung's Galaxy Fold Unveiled at Unpacked

    Samsung Announces Galaxy Fold, a $1,980 Foldable Phone

    Samsung officially announced its new foldable phone, dubbed the Galaxy Fold, at its Unpacked press event in San Francisco Wednesday morning. The device features two screens that unfold to a tablet-sized slate. “We are giving you a device that doesn’t just define a new category, it defies categories,” said Samsung senior vice president of product [...]

More From Our Brands

Access exclusive content