Netflix Boost Mobile Video Quality Without Needing Faster Broadband

Internet video streaming giant Netflix is constantly trying to improve video quality over low-bandwidth (slow) broadband connections and a new change looks set to deliver more efficient video encodes (higher quality), albeit without needing a faster Mobile Broadband service.

Earlier this year we ran an article that examined the dramatic impact of advanced video compression methods on video streaming quality and broadband speeds (here), which among other things showed how today it’s possible to stream a much higher quality video online and all without needing a faster broadband connection. This is important because online video content accounts for around 70% of consumer Internet traffic (here).

In keeping with that Netflix has just moved to improve its video encoding on mobile platforms by introducing two new methods (AVCHi-Mobile and VP9-Mobile), which bring improvements to compression, optimal encoder settings and per-chunk bitrate optimization.

Netflix’s Anne Aaron said:

“Last month, we started re-encoding our catalog to generate the new mobile bitstreams and the effort is ongoing. The mobile encodes are being used in the brand new downloads feature. In the near future, we will also use these new bitstreams for mobile streaming to broaden the benefit for Netflix members, no matter how they’re watching.”

According to the streaming giant, all of the above changes combine to result in “better video quality for the same bitrate” compared to their current streams (AVCMain).

Netflix’s Video Encoding Methods

* AVCMain: Our existing H.264/AVC Main profile encodes, using per-title optimization, serve as anchor for the comparison.

* AVCHi-Mobile: H.264/AVC High profile encodes using more optimal encoder settings and per-chunk encoding.

* VP9-Mobile: VP9 encodes using more optimal encoder settings and per-chunk encoding.

Netflix will tend to choose either AVCHi-Mobile or VP9-Mobile, depending upon the type of video content being shown (i.e. they each work better for different things). Generally AVCHi-Mobile streams were found to deliver the same video quality at 15% lower bitrate via one measure and at 19% lower bitrate according to Netflix’s own measure of Video Multimethod Assessment Fusion (VMAF) test.

By comparison the VP9-Mobile streams showed more gains and can deliver an average of 36% bitrate savings according to both tests that were run. As a result even somebody who suffers a Mobile Broadband (3G or 4G) speed of 1Mbps should benefit from “noticeably better visual quality“.

Incidentally some may ask why Netflix has yet to support the arguably more favourable H.265 standard and the reason has to do with support and restrictions on certain platforms. For example, Android (Google) somewhat requires VP9 for Netflix’s new download feature and some Internet-connected TV’s only support up to H.264 etc.

Likewise H.265 needs a faster processor (not always present in many Netflix supporting TVs etc.) and there can also be issues with royalties and licensing.