You might have seen our press release that Opera’s Rocket Optimizer can now optimize encrypted video streams. The attentive reader will already have halted and said, “wait, what?”. In this blog post, we’ll explain how this works.

Rocket Optimizer works at the ISP level, ensuring that all subscribers get an optimal experience. When available bandwidth is limited, it does this by dynamically altering the bit rate of videos that pass through, as videos are prime users of bandwidth. Obviously, if the video is encrypted, this doesn’t work, so new technology is needed.

The ISP has access to some information of encrypted data, which it needs in order to transfer the packets. It knows the destination, both in terms of domain name and IP address. It can also see how much data passes through, and how fast. A sudden surge of one-way traffic from your favorite video site typically means you are streaming a video, although the ISP has no idea which, and cannot see any data.

Some content providers are able to do adaptive streaming on their own, they figure that if the client is not able to receive a lot of data, they should send less. Although if available bandwidth in a network varies, a content provider might try a higher bit rate, only to have the stream stall once less bandwidth becomes available. Rocket Optimizer is able to improve this – if Rocket Optimizer knows that there is limited bandwidth available to the subscriber, it will limit and stabilize the bandwidth to the content provider, thus giving the content provider an out-of-band hint that the bit rate should be reduced. An appropriate bit rate will thus be selected before the stream even hits the area of limited bandwidth, without even attempting to decrypt or decode the data stream.

Where helpful, Rocket Optimizer dynamically throttles the bandwidth between the ISP and content providers, thus freeing up bandwidth between the ISP and the subscriber. This means there will be a better overall experience for all subscribers, and it means the video in question will stream fluently, without stalling and stuttering, so also a better experience for the individual subscriber.

Rest assured that the security and privacy of users is of primary concern to us in Opera. But with lots of smart engineers, we can improve even your encrypted data 🙂

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