Thursday, 24 November 2011

Mobile video optimisation - different perspectives

I had a briefing call with one of the mobile video optimisation companies yesterday, discussing the role played by network boxes that can compress, rate-limit and otherwise change a downloaded video stream.

It's an area I've been critical of for a while - especially where the network 'transparently' alters video content, without the explicit consent of either video publisher or end-user. I recognise that's a useful short-term fix for congested networks as it can shave 20-30% off of data throughput, but I also think that it's not a viable model in the long term.

Basically, publishers don't like the idea that some device in the data path "messes with our content", and in many cases users and regulators won't like it either. Some of the vendors suggest that reducing video "stalling" by optimisation actually improves the quality of user experience (QoE), but there are also other approaches to that which are more "consensual".

It was interesting to read the other day that Verizon's Video arm (formerly V-Cast) is working with its network teams to pre-define properly "optimal" formats for video depending on network connection, device type (ie screen & processor) and even user dataplan. In my mind, that's totally acceptable, as the content publisher/aggregator is working hand-in-hand with the network team to create a balance between QoE, network integrity and "artistic integrity". Collectively, they've thought about the trade-offs for both network and user in terms of quality, cost and performance. Presumably they also looked at the role of CDNs, adaptive bitrate streaming, on-device caching and assorted other clever mobile-video tech. According to a related article, they can't use WiFi offload because their content rights agreement is for 3G/4G only - another good illustration of the complexities here. All in all, it sounds like a great example of "holistic" traffic management, working with the various constraints imposed. I assume they have a roadmap for further evolution as it all matures.

But there's a million miles between that philosophy, and the type of non-consensual optimisation that's increasingly common for normal Internet video traffic destined for mobile devices, where the network unilaterally decides to alter the content. We're seeing solutions getting a bit smarter here - for example, only acting if the cell is actually busy, but there are various other use cases where it's more directly about the operator's costs.

The vendor I spoke to yesterday mentioned scenarios like shared networks (where each operator pays a share of costs based on traffic volumes), or where the backhaul is obtained from a third-party fixed operator at variable-cost. Another scenario I've heard (usually more for caching / CDNs) is around international transit in parts of the world with expensive connectivity. But another use cases was where the network is uncongested but high-quality video was being downloaded at high speed. In that instance "we can take 20% of the data stream off the top, and they won't notice".

Here is where we differ. In my view, if I (as a customer) pay for Internet Access, then I expect that the bits and bytes that come out of the server are the same bits and bytes that arrive on my device. The server owner thinks the same. Yes, in certain circumstances I'll accept a trade-off if it improves my QoE, as long as I am told what's happening and opt in: imagine an icon appearing, indicating "optimiser on", or a switchable user-controlled optimiser like Onavo's for reducing roaming traffic. But I'm not prepared to accept a lower quality just because the operator has been stupid enough to agree contracts for a shared network, with terms that don't take account of the types of retail broadband service its selling to its customers.

"Oh, I'm sorry Mr Bubley, we know you paid £1000 for the flight, but we've downgraded you to economy class because it's a codeshare flight, and we have to pay our partner airline £500 extra per-seat for business class passengers". I'm sorry, but that's your problem and not mine.

And as for the notion that the Internet connection can arbitrarily decide that "I won't notice" if it chops up & reformats my data? Hello? How do you know that? Maybe I've encoded something into it steganographically in the background? Maybe I've PAID for content of a specific resolution, and I have a contract with the publisher? Maybe I'm willing to take the trade-off of throttled buffered' throughput, because it's going to a background app for viewing later? If I've paid for my 2GB per month, I'll use it the way I like, thank you very much. If the network's busy, fine - tell me (and/or the publisher) & I'll use WiFi or download it later or *I* will make the decision to drop the quality if I want instant gratification.

I've got a lot of sympathy for operators that have genuine peaks and troughs of demand, or that are constrained in terms of supply by spectrum shortages or difficulties obtaining cell sites. But I've got less sympathy for companies that sell a product ("2GB of mobile Internet access at up to 10Mbit/s") and then realise they can't deliver it, because it doesn't match up to their network's capabilities or cost structure.


But it struck me that the reason that telecom operators (especially mobile) think that this is OK, is that degrading quality is at the core of their business proposition. For the last 100 years or so, we've had to deal with the fact that our natural, wideband human speech has been squished into 3KHz pipes for transport across the network. It's "optimised" (ie downgraded) at the microphone on your handset. Of course, now we have service providers trying to monetise HD voice - and expecting you to pay a premium just for transporting what your vocal cords have been putting out all along.

I'd love to know if there's internal transfer-pricing going on at Verizon for the video service. Is VZW actually "monetising" its optimisation capabilities and charging the Video department for the privilege? Or is it being done for mutual benefit, without money changing hands? I suspect the latter, which is the model I see most (but maybe not all) consensual video optimisation working out.

Oh, and if I ever go for a drink with this particular optimisation company exec, I'm going to have a word with the barman. I'll tell him to pour 80% of his pint of beer as normal, but top up the other 20% with coloured water. I'm sure he won't notice.

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