Popular video-streaming service Netflix made a significant change to how it works when it recently announced it’d allow users on mobile devices to download complete videos, instead of offering only streaming. It was a smart move on behalf of Netflix, as it gives mobile users the ability to download movies and TV shows on Wi-Fi and then consume those videos where they may have limited (or no) internet access.
And while that flexibility may solve one problem (access to Netflix content), it can create another; maxing out available storage. Modern mobile devices run the range from 8GB to 128GB of storage. And with modern devices doing more and more, internal storage exists at a premium. The new offline mode provided by Netflix wouldn’t get much use if it filled up users’ devices after one or two sessions. With this in mind, Netflix had to devise a way for those downloaded files to use as little space as possible:
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.
As VP9 is a Google-developed codec, it’s not currently supported by Apple. For now, Netflix is using a slightly modified version of H.264 on iOS devices. Apple hasn’t yet indicated if it will support VP9 in the future.