Netflix spruces up video compression

How-file-compression-worksAfter four years working on it, Netflix is set to roll out a new video-encoding system which promises a significant cut in general internet traffic.

The new system will encode from the raw source material more intelligently and take into account if the material can benefit from higher bit-rates, or whether identical quality can be maintained with less space and bandwidth.

Netflix video algorithms manager Anne Aaron said that at the moment Netflix allocates the same about of space for My Little Pony that it does as for The Avengers. This is because animated material often contains large blocks of colour and features relatively little movement, depending on the quality and style of the show, and very large sections can often be re-used in the encoding process, saving space both on the server and in transit.

But the Avengers have large numbers of scenes with high-levels of activity and frame changes and there is not a pixel left that can be recycled. Such material continues to need the maximum amount of bandwidth.

When a network devotes inadequate bandwidth to a movie, you get a lot of blockiness or artefacts becoming very evident if the camera moves too fast or records action which moves too fast.

Netflix have been keen to make an estimated 20 per cent saving without sacrificing quality of image. IT solved the problem by offering a bottle of champagne to any employees at the company’s Los Gatos offices who could spot the difference between two side-by-side playbacks of identical content encoded with both the old and the new method. The champers is still chilling.

Netflix intends to have completed the re-cast of all its video streaming content by the end of 2016, by using  its vast global array of servers to process chunks of new encoding from splits of its content, before re-assembly – all during the off-peak hours for net traffic.

The initial batch of 1000 re-encoded videos are to be completed by the end of March next year, according to the company, with the entire petabyte of video finished nine months later.

Netflix video accounts for 37 per cent of all North American traffic – the company’s own contribution to the estimated 69 per cent of all web traffic which is occupied by streaming video providers such as itself, Amazon Prime and Hulu.

It has to do something fairly fast as it is going to be streaming at 4K with higher frame rates and HDR so any savings are needed.