Netflix has developed algorithms that dynamically adjust the bit rate to match the content being streamed by viewers.

The idea is that if a viewer watches 4K or HDR content, the bit rate drops. The company describes this process as “optimised shot-based encodes” for 4K.

The blog gives an example of a 4K animation title episode, where a 640×480 encoding resolution is paired with a 4:3 PAR to achieve 16:9 DAR.

According to Netflix, the new process will enable it to reduce the average bit rate by 50 per cent with no loss in image quality. It adds that viewers who have a limited bandwidth will also get a better image quality.

It also adds that the number of rebuffers per hour is expected to reduce by over 65 per cent; while the reduced bitrate together with some Digital Rights Management (DRM) system improvements result in reducing the initial play delay by about 10 per cent.

Netflix said it has started re-encoding the 4K titles in its catalogue in order to generate the optimised streams and expects to complete the process in a couple of months. We continue to work on applying similar optimizations to our HDR streams.

The blog goes into the process in much more detail.