Netflix has spent years working on a way to reduce the data consumption of its streaming content.
The company finally announced in an official blog post that it is in the process of rolling out an encoding optimization update featuring an ‘optimal per-title bitrate ladder’ which adjusts the level of quality depending on the content being streaming – as opposed to its old blanket policies.
The update will cut the data consumption of Netflix streams by approximately 20 percent.
In order to continue delivering the same quality video each title will now receive a unique bitrate ladder – tailored to its specific characteristics.
Netflix uses the H.264/Advanced Video Coding (AVC) compression algorithm for its content.
In late 2010 its engineers created recipes that worked best across its video catalogue (at that time). They tested various codec configurations and performed side-by-side visual tests to settle on codec parameters that produced the best quality trade-offs across different types of content.
A set of bitrate-resolution pairs were created so that the bitrates were sufficient to encode the stream at a certain resolution.
Netflix said: “This “one-size-fits-all” fixed bitrate ladder achieves, for most content, good quality encodes given the bitrate constraint. However, for some cases, such as scenes with high camera noise or film grain noise, the highest 5800 kbps [5.8 Mbps] stream would still exhibit blockiness in the noisy areas. On the other end, for simple content like cartoons, 5800 kbps is far more than needed to produce excellent 1080p encodes.”
The update in a nutshell:
With the new update each Netflix title will receive its own set of algorithm rules.
As Netflix Video Algorithms Manager Anne Aaron told Variety: “You shouldn’t allocate the same amount of bits for ‘My Little Pony’ as for ‘The Avengers,”
Animated content such as ‘My Little Pony’ or ‘BoJack Horseman’ can now be transmitted at a lower bitrate for a given resolution compared to a Hollywood action movie with fast-moving scenes. The animated content will still be in 1080p but the bitrate will be lower than that of a more visually complex action movie such as ‘The Avengers’.
The changes will reduce the bandwidth requirements of Netflix’s entire collection by roughly 20 percent, on average.