Streaming To Your Benefit
I was chatting to the Asia-Pacific vice president of a CDN lately and naturally, we talked about live streaming protocols. The inevitable comparison between HTTP-based Smooth Streaming and RTMP/Flash Dynamic Streaming was brought up as well as, of course, the rising dominance of HLS (HTTP Live Streaming). Three streaming protocols being advocated by Microsoft, Adobe and Apple respectively. According to the VP, his discussions with professionals worldwide pointed to HLS as being the eventual undisputed leader, thanks to the tandem rise in Apple devices.
Let’s back-track to a streaming primer first. RTMP/Flash is currently the most widely-used protocol, with its plug-in resident in 98% of browsers worldwide. RTMP’s dynamic bit rate technology has just seen the release of FlashAccess as a DRM support, but this is still fairly new. End-to-end latency is still behind that of HTTP streaming. Not to forget, Flash requires dedicated and costly streaming media servers and is not exactly firewall friendly.
Microsoft’s product seems to be the best technology at first glance. It requires no special hardware, is firewall friendly and its obvious HTTP scheme allows edge-caching CDNs (which are simple HTTP proxy servers) like Akamai to reach deep and close to end-users. Coupled with its default fragment length of 2 seconds, Smooth Streaming is exactly what its name suggests. PlayReady also boosts its credentials as a solid DRM product.
The disadvantage lies in Microsoft’s Silverlight as being the foundation for the Smooth Streaming product. Silverlight’s plug-in must be downloaded by users for their browsers (an apparent turn-off) and approximately half the world’s browsers simply lack it. Although Microsoft claims this number is growing, having your competitor’s video player outnumber yours by two to one is a big disadvantage. Thus, Silverlight seems to be on the same stage that Beta was when it battled VHS for the home video market: the better product seems losing out to mainstream appeal.
Like what the VP said, Apple’s ascent as a device giant may take time, but it will bring HLS along to the summit with it. HLS has the benefits of being HTTP-based but provides for an MPEG-2 transport stream and an index file that is fragmented (its rivals are contiguous or connected as ‘one’ file). This offers various benefits. But each file fragment is 10 seconds long. Plus, the fragmentation requires an additional processing step so its end-to-end latency is the worst. But being made for Apple is the only good thing going for it; while Flash and Adobe slug it out on PCs, Steve Jobs has simply shut his rivals out by being the exclusive streaming platform for his devices.
Sure, Apple’s dominance is beyond the scope of this post (it has everything to do with that magical ‘network effects’ that Harvard professors love to talk about) but the fact is that by 2014 Admob projects 400 million iPads will be in the market (let alone iPhones and iPod touch devices) and this means the world had better sit up and take notice.
As broadcasters and online video professionals, I hear everyone take up a position on which is best. However, the true answer lies in your organization and what makes for the best approach to your customers. Invariably that means riding the wave of multiple technologies for the time being. At Astro, our online Silverlight player took the form of an iPhone App. But streaming to iOS devices is equally feasible by us simply pointing a separate HLS stream to a mobile-formatted site. We require our premium content to be protected and we’re fine with asking our paying subscribers to download the plug-in. We ensure them that the trade-off is the best streaming experience.
Also, if you’re a free-to-air broadcaster you might take a position that you don’t need DRM and that RTMP/Flash is your best bet. By all means, go for it. Just don’t forget that app for iPhone and iPad. There’s no way you can squeeze RTMP on a mobile site because Safari won’t support it (some CDNs will claim to be able to tunnel your RTMP stream through HTTP headers – that’s difficult and clumsy) so don’t bother.
Lastly, you could hedge your bets for HLS only. There’s nothing wrong with that if you think your customers are on the high-end and you want them to view your content from their iOS devices. The mobile site will be perfect, as will the two separate apps you’ll need if it comes to that (app or mobile site – that’s another interesting debate). If you don’t need authentication, then all the better. In years to come, iOS devices may become so dominant that you won’t even need to bother about Flash and Smooth Stream anyway.
So while I think the jury is still out on which is the better streaming technology, I feel it really boils down to what is best for your business model and your consumers. Until that verdict is finally handed down, I’d plea-bargain for safety and cover my streaming bases.