The classic definition of a CDN, or content delivery network, is an aggregation of servers dishing out live streams, on-demand content and other files to end users on behalf of various clients. In broadcasting, typical clients range from small radio and television stations to larger broadcast networks and media conglomerates. The CDN’s role in the broadcast space isn’t so much changing but it is evolving. The now-simple idea of distributing content grows more complex by the year. The explosion of mobile streaming and the ever-expanding OTT universe is evidence alone.
Simply put, to provide an audience with the ability to access content with whatever device and network they use, there are more formats to learn, varying bit rates to accommodate, more complicated signal flow to navigate, and more devices specifications to understand. The good news is that CDNs have the tools, the knowledge and, most importantly, the relationships to help broadcasters evolve their platforms.
Television
The slow-boil behind “cutting the cord” and “ditching the dish” has generated enough steam to send a clear message: A growing number of consumers worldwide are leaving cable and satellite services behind in favour of accessing their entertainment through OTA digital HDTV broadcasts and through the internet.
Viewers that have transitioned to over-the-air digital receive additional benefits beyond free TV services, from a higher-quality picture to digital subchannels (due to the ability to fit more digital channels in a slice of spectrum than a typical analogue channel).
What viewers miss in reverting to terrestrial TV is selection. The number of channels sharply decrease upon cutting the cord, though the rapid proliferation of OTT options has eased the pain for many consumers.
That proliferation also means more complexity: more formats and varying bit rates equate to wider ranging transcoding requirements. It also means staying on top of changing client and consumer needs. For the CDN, this means integrating new technologies into the streaming architecture – and establishing the necessary relationships to make it happen.
Content management
Digital content management is imperative in any modern broadcast architecture. It has become the overarching layer that allows broadcasters to effectively move files and manage media across multiple components, from servers and editing systems to online, near-line and archival storage systems.
Simplifying delivery across many platforms is among the main responsibilities of the CDN. For this responsibility, the CDN has a limited number of true options for packetising media into multiple protocols:
Adobe, the original developer of the Real-Time Messaging Protocol (RTMP) for delivering video, audio and data to many platforms. Reliable, if expensive.
Wowza Media, supporting all major streaming protocols with a flexibility to quickly adapt to new devices and software.
RealNetworks, which has grown to support more protocols beyond Real Media players but remains expensive.
Emerging server technologies such as Evostream, which look promising to date but require more testing.
We work across many of these server technologies and focuses on cost-efficiency and the ability to adapt to new targets with minor changes. Wowza Media particularly excels in supporting all major streaming protocols cost-efficiently, and evolved grown from strictly RTMP-to-Flash delivery to quickly supporting most emerging OTT and mobile-device protocols.
MPEG-DASH represents one interesting emerging protocol, efficiently making HTTP-based file segments available in a variety of bit rates. It ultimately marries tried and true MPEG compression algorithms with dynamic adaptive streaming over HTTP, becoming the first globally-accepted, adaptive bit rate HTTP streaming option.
The emergence of MPEG-DASH follows along similar lines as Apple HLS, Adobe HDS and Microsoft Silverlight Smooth streaming – all HTTP-based protocols that offer carrier-grade delivery. The HTTP-based architecture ultimately simplifies delivery to multiple devices.
The openness of MPEG-DASH further simplifies the implementation layer for playback. It’s a less cumbersome protocol essentially, making it easier to surpass firewalls and player-related issues at the consumer side. Its openness and simplicity makes it a very attractive option for OTT services that are targeting a continually growing number of devices. This translates to the consumer experience, as MPEG-DASH can easily adapt to varying networking conditions and provide excellent playback quality.
Enhanced services
Closed captioning in video streaming is emerging as an important enhanced service. Typically, it’s down to two options: create the captions from scratch, or integrate a solution for automated caption creation.
We have partnered with Ensemble Video to provide users with a video content system to manage, coordinate and syndicate video content within their architecture. Essentially, it provides the toolsets for broadcasters and media organisations to manage their streaming libraries online, and publish and that distribute content across many platforms.
Ensemble Video’s playout system also establishes an automated workflow that creates and delivers closed captions through the player. This is especially beneficial to a production house or a mobile truck that is doing a lot of video production but lacks the time or resources to create captions in-house.
Ensemble Video’s solution is intriguing as it is rooted more in the higher education space, and its strict ADA compliancy, as opposed to broadcasting. Like a production house, educational video production is typically high in volume – and lacking in the resources to efficiently caption content. This can be especially helpful in the OTT space, where multi-language captioning is more often needed for international OTT services that deliver media content to multiple regions and/or countries.
Applying proven captioning solutions like Ensemble Video to broadcast also eliminates the need to hunt for separate, more expensive hardware-based platforms like Elemental or Haivision to support in-stream captioning.
Online radio
Few radio stations today lack an online presence, and most stations with active streams are looking to monetise their efforts. Dynamic ad insertion offers, perhaps the best opportunity to generate revenue from their online properties, and reach very specific audience subsets (age, gender, geographic location) with targeted content.
A number of software-driven ad insertion technologies exist today to support pre-roll, mid-roll and post-roll placements for live and on demand content. Pre-rolls are the easiest to do (client-side or server-side) and offer the most value to the broadcaster. For some broadcasters, ad replacement is a must to stay within the distribution rights of advertisement campaigns that are limited to the local OTA broadcast area.
Mid-roll ad replacement requires more technical expertise to set up, typically relying on metadata or tone-based triggers such as contact closures coming in and out of an ad break. The CDN architecture can be set up to receive and recognise the trigger or tone that signals content should be replaced with a spot from the ad server.
We partner with AdsWizz for live and on-demand ad insertion, able to handle pre-roll, mid-roll and post-roll ads. The current architecture supports Flash and Icecast audio streaming of Mp3 and HE-AAC formats, as well as progressive download MP3 podcasts.
AdsWizz brings an additional capability by supporting Target Spot, an ad network that allows broadcasters to acquire and approve additional campaigns for unsold ad slots. This is also built into the StreamGuys CDN architecture, and is representative of how a CDN can help support financial gain and operational efficiency for online radio broadcasters.
Media playout
Most radio stations exploring ad insertion today are successfully doing so using Flash players, with HTML5 player support an emerging trend.
The Flash platform supports tightly synchronised ad insertions and companion banner ads. This is made possible through metadata support that aligns banner ad changes with audio, creating a more satisfying user experience and value to the advertiser
The HTML5 platform requires additional work-around software to align audio with banner ad changes. The major bonus here is format and device flexibility: The use of HTML5 extends the benefits of synchronized audio and banner ads to iOS devices, for example.
HTML5 also offers better overall support for mobile devices – a more exciting proposition for web developers working in the broadcast space. An HTML5 Player with rollback to Flash (a service StreamGuys offers) represents a perfect complement of technologies and functionality.
The bleeding edge
CDNs are equipped to more than just deliver content. Today, they help broadcasters increase reach, expand viewer bases and generate revenue. This could be through any of the above applications discussed, as well as others such as mobile app support; exploration of next-generation high-efficiency codecs like HEVC H.265; and the provision in-depth analytics to better understand audiences and the overall business of streaming.
Business analytics are especially taking off in the streaming world, offering richer data that note audience numbers, geographic locations and average dwell times. These services are important to help CDNs and broadcast clients understand the appropriate time to scale services at the infrastructure, from adding new live server nodes to increasing storage and for on-demand files.
The role of the content delivery network has certainly evolved, from supporting more formats, bit rates and devices today to helping broadcasters develop a future roadmap through audience analytics and measurement to generate revenue. How well the CDN accomplishes these goals will certainly in part lie in developing key relationships with industry vendors, with the intent to bring more advanced functionality and services into the streaming architecture.
Eduardo Martinez is Director of Technology and Andrew Jones is Director of Sales Engineering of StreamGuys, a global CDN based in California.