Since 2011, the company has been working on a new form of video encoding that operates on a per-title basis, instead of applying exactly the same compression to each video. In a post on the Netflix Tech Blog, the authors compare simple animation like BoJack Horseman to something of more “average” complexity: Orange Is The New Black.
“You shouldn’t allocate the same amount of bits for My Little Pony as for The Avengers, Netflix video algorithms manager Anne Aaron told Variety. Even further, you can’t assume that you can use the same encoding across an entire season of a TV show. “Each episode could be very different,” Aaron said.
Each of the those titles benefits from a different type of encoding, but it doesn’t end there. The per-title optimization also varies depending on the device the viewer is using, since an iPhone is going to have different needs than a new 4K Ultra HD TV.
As the graph above shows (the y axis stands for Peak Signal-to-Noise Ratio), the new encoding not only allows for cleaner-looking streams at 1080p, but also allows for a lower bitrate for the same resolution.
While Netflix may be alone when it comes to broadcasting this new approach, there may well be other companies working on it. Amazon could be cooking up something similar for its video library, possibly using the relatively new HEVC codec. The codec is complex, but due to its young age, there is likely to be plenty of room for optimization, and it’s already in use for Amazon’s HDR content.
Netflix is currently busy re-encoding its entire library, which is a massive undertaking. The result could reduce the data used per stream by 20 percent, according to Variety. While this is good news for those with tight bandwidth caps, all Netflix subscribers will benefit, as the new encoding should also result in better looking streams through optimization of video delivery. It isn’t likely this will be noticeable on every title, but simple animation should benefit especially from the new technique.
The company hopes to have more than 1,000 titles using the new encoding ready by the end of the year, and projects the entire library will be re-encoded as of early 2016. For more information on how exactly the new per-title encoding works, see the lengthy blog post detailing the new process at Netflix.
