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What Is DRM?

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Now let's take a quick look at how DRM works in a browser-based environment, and the transition from plug-ins to HTML5.

From Plugin to HTML5

As mentioned, in the past, the DRM player was typically a plugin like Flash or a separately downloaded player like Widevine Classic. Over the last two years, several standards-based technologies have been implemented to enable the browser itself to function in this role. While individually these technologies may seem technically complex, as you'll see, the big picture is easy to grasp. These technologies are as follows:

Media Source Extensions (MSE)

MSE is a W3C HTML Working Group specification for a JavaScript interface to playback media data. Browsers and devices that support MSE can play back chunks of video (or byte-range requests for video segments within a single file), which enables both live and VOD playback of adaptive bitrate streams, complete with closed captions. While the original HTML5 video tag enabled progressive download of a single MP4 file, MSE enables full adaptive streaming

Dynamic Adaptive Streaming over HTTP (DASH)

DASH is a standardized file format for HTTP-based adaptive streaming that is similar in form and function to Apple's HLS or Microsoft's Smooth Streaming. Like all HTTP-based adaptive streaming technologies, there are two types of files in the final output packaging; fragmented videos files (or byte-range requests for segments within a single file), and manifest files, which identify the location of the various streams in the adaptive group, and the location of the chunks or byte-range requests of the individual segments. In use, most DASH content consists of separate MP4 files (one for each encoded stream in the adaptive group), and MPD (Media Presentation Description) manifest files.

MSE and DASH fit together like hand in glove. That is, for a browser or device to play DASH files, it must support MSE. So MSE provides the playback capabilities, while DASH is one of the supported file formats that MSE can play.

Encrypted Media Extensions (EME)

EME is another JavaScript API that enables HTML5-based DRM by extending MSE with application programming interfaces (APIs) to control the playback of protected content. EME works by incorporating what's called a content decryption module, or CDM, into the browser, device, or mobile operating system, which allows the browser or device to communicate directly with the license server.

Common Encryption Scheme (CENC)

CENC details the standard encryption and key mapping techniques used to store the DRM-related data for one or more DRM technologies with the compressed audio/video data. As you'll see, the ability to manage multiple DRMs is critical because most browsers or other devices will only support one DRM flavor, making multi-DRM support a necessity for most video producers.

ISO Base Media File Format (ISO-BMFF)

ISO BMFF is a standardized file format that contains the DASH encoded video, and CENC DRM metadata.

These concepts come together in a presentation by BuyDRM at Streaming Media West 2014 that is available here. On the left is the ISO BMFF, which contains the DASH encoded content and CENC DRM information for three DRMs. This information is delivered via the cloud to an EME-compatible browser that communicates with the appropriate license server (1, 2, or 3, but not all three), and obtains the decryption key. Once decrypted, the DASH data is played back via MSE.

Now that you know the acronyms and how the plumbing works, let's see how EME has fundamentally changed the number of DRMs that most streaming publishers will need to support.

Working with EME

When DRM is tied to a plugin, the DRM works on any browser that supports the plugin. So if you protected your content with Adobe Access via the Flash Player, Adobe Access worked within any browser that supported Flash.

In contrast, with EME, each platform decides which DRM to support, and as shown in Table 1, the major browsers all support different DRM technologies. Not surprisingly, Microsoft supports its PlayReady technology in Internet Explorer and Edge, Google supports Widevine in Chrome, and Apple supports FairPlay in Safari. Firefox supports both Adobe Access and Widevine. As a practical matter, this means that technologies like DivX, or VCAS, or Marlin, which aren't integrated into any browser, are unavailable for browser-based distribution without a separately downloaded player, which are increasingly anathema in an HTML5-centric world.

Note that the information in Table 1 was largely pulled from DRMToday's website, which is a great resource for learning which DRM is supported by which platform and specs like HbbTV.

BrowserDRM Provider
Chrome (35+)Widevine
Firefox (38+ Windows)Adobe Access
Firefox (47+ Windows/Mac)Adobe Access, Widevine
IE 11+ on Windows 8.1+PlayReady
Microsoft Edge (Windows 10+)PlayReady
Opera (only on Linux)Widevine
Safari (8+ on OS X)FairPlay

Table 1. DRM support by browser.

Moving from desktops to mobile players, when securely distributing to the mobile devices, you have two options, browser-based playback, and playback within an app. In terms of browser-based playback, the vendors remain true to form; Apple supports FairPlay in iOS 6+, Google supports Widevine Classic in Android 3+, and Widevine Modular in Android 4.3+, while Microsoft supports PlayReady on the Windows Phone.

Of course, apps provide much more freedom of choice. For example, BuyDRM, which enables PlayReady on all mobile devices, with Marlin, the open-standard DRM solution, on iOS and Android devices. Basically, browser-based playback enables one DRM per platform, while an app usually lets you select from multiple DRMs.

In OTT, PlayReady dominates, with support on most platforms except Apple TV, which of course only supports FairPlay. Widevine is also available on Google devices like Chromecast and Android TV, but not Amazon Fire TV, which uses PlayReady. Most smart TVs support PlayReady, with a smattering of support for Widevine and Marlin. Both Xbox and PlayStation support PlayReady, with the Sony devices also supporting Marlin.

Choosing a DRM and Licensing Partner

By this point, you probably understand that to choose a DRM technology, first you choose the playback platform, and then you see which DRM or DRMs it supports. To support all the major browsers on computers, you'll need to support multiple DRMs. In addition, since EME doesn't yet support 100% of target viewers, any DRM strategy based around EME will have to enable fallback to a plugin-based DRM, usually either Adobe Access via Flash or PlayReady via Silverlight. Complicating this fallback strategy is Adobe's decision to make Access primarily available only within its own Primetime platform, so if you're not a Primetime user, you may not be able to offer fallback to Flash.

On mobile platforms, you have to decide whether to produce an app or to distribute via the browser, with the former offering much greater flexibility regarding choice of DRM. Once you move into OTT and Smart TVs, it's a device-by-device determination; identify the device that you want to serve, and then identify the supported DRM or DRMs.

DRM Licensing Options

After choosing the target platforms and identifying the DRM technologies you must support, you should choose a licensing provider, which involves multiple factors, including whether to go direct with those vendors that support (or require it), or to use a licensing partner. Obviously, the DRMs supported by a potential partner is a major consideration, and a partial list of service providers is shown in Table 2. Note that this is a fast moving market, so check with the service provider before making any decisions.

CompanyMicrosoft PlayReadyGoogle WidevineAdobe AccessApple FairPlayMarlin
Adobe Primetime DRM (coming Q4 2016)YesYesYesYesNo
Cisco VideoGuard EverywhereYesYesNoYesNo
DRM TodayYesModular/ClassicYesYesYes
Microsoft AzureYesModularNoNoNo
Vualto vudrmYesYesYesYesYes

Table 2. A partial list of multiple DRM service providers.

As an aside, though Netflix has licensed FairPlay from Apple for the playback of DASH-encoded files using EME and MSE, it appears to be only content owner with that privilege. All vendors listed in Table 2 can supply FairPlay for protecting HLS content, but not DASH. While this may change later in 2016, this was true as of June 2016.

To the list shown in Table 2, you should add online video platforms (OVP) like BrightcoveKaltura, and Ooyala, which all offer various DRM technologies to enable native EME support in current browsers, fallback to Silverlight or Flash for older browsers, as well as SDKs to assist with delivery to mobile and other devices. 

Similarly, in 2016, Adobe introduced the Adobe Primetime HTH TVSDK that uses the native EME-driven DRM of each browser. Adobe also announced a partnership with ExpressPlay to provide a cloud service for issuing licenses in all required DRMs, which should be available in late 2016. Customers may use the Adobe cloud for DRM licensing, or use a limited set of license administrators in conjunction with the Adobe Primetime TVSDK on the client. Essentially, if you're distributing your content through an OVP or similar platform, that service or platform should be able to either provide the necessary DRM, or an easy path to integrating third-party service providers like those shown in Table 2.

Again, as mentioned, Adobe has stated that they will no longer support third-party DRM resellers, which could mean some changes to Table 2 regarding Adobe Access in 2016 or beyond.

Packaging Your Content with DRM

For developers managing their own distribution and player development, the integration of DRM into your encoding and packaging workflow is another major factor, and different services take different approaches. For example, castLabs, owner of DRM Today, offers a cloud service that can input over 100 audio/video codecs, and output DRM-protected packaging for DASH, Smooth Streaming, and HLS, complete with closed caption support.

If you're encoding in a third-party cloud service, check which DRM providers it directly supports. For example, Encoding.com supplies Widevine licensing directly, but integrates with BuyDRM to manage PlayReady licensing. BuyDRM also has deployments in Amazon Web ServicesAkamai, Brightcove (Zencoder), Encoding.com and Google Cloud. If you're encoding your own content, check if the vendor can supply encoding/packaging capabilities for your chosen platform, whether Windows, Linux, or the cloud.

Check whether your service providers or partners support dynamic encryption, as opposed to static, which can simplify your workflows and save storage costs. For example, the Wowza Streaming Engine can dynamically encrypt and package live and VOD content for delivery via Apple HTTP Live Streaming (HLS), Microsoft Smooth Streaming (MSS), and Dynamic Adaptive Streaming over HTTP (DASH) with PlayReady and Verimatrix VCAS DRMs using three third-party DRM service providers, BuyDRM, EZDRM, and Verimatrix.

With dynamic encryption, which is available from other vendors, including Microsoft Azure, only a single copy of the unencrypted content needs to reside on the server. In contrast, with the static packaging model, you would have to create and store the final encrypted packages for all technologies for all content, multiplying your storage costs. The potential downside of dynamic packaging is a slight playback latency, which will vary by technology provider.

Pay TV-Oriented DRM Services

If you're a pay TV service provider also distributing to streaming and other clients, there are several other alternatives you should consider. For example, Verimatrix sells DRM and other products into the broadcast and pay TV markets. Since many of its customers are expanding into streaming delivery, Verimatrix created the MultiRights OTT service, which manages its core VCAS DRM for delivery of services to iOS, Android, legacy desktop browsers, and STBs, and adds Widevine for Chrome and other proprietary environments, and PlayReady for integrated license management for Smooth Streaming and DASH service delivery to closed Xbox and Windows environments.

NAGRA, the developer of the anyCAST Security Services Platform for Digital TV service providers, takes a different approach. Rather than use third-party DRM platforms to support computers, mobile devices, and other CE platforms, NAGRA has extended its own DRM technology to these platforms via secure players and other technologies.

Similarly, Cisco VideoGuard Everywhere (VGE) allows pay TV services to securely extend playback beyond the STB to computers, mobile devices, and gaming consoles. In addition to access to the DRM technologies, with VGE Cisco assumes responsibility for integrating all components of the video service solution, including different DRM systems, monitoring the integrity of the service after deployment, and responding to service breaches identified.

Business Models and Pricing

When choosing DRMs and providers, be sure to check that the combination supports both your target platforms and planned business models. If your model is streaming to online clients, that should be fairly simple, as virtually all DRMs and DRM providers support this. On the other hand, if you'll be implementing a subscription model, or the ability to download and play the content offline, or download it on your computer and then sideload it to another device, you could have issues.

Beyond business models, you should price both startup and ongoing costs, particularly those involved with supporting additional platforms, which varies significantly from provider to provider. For example, many service providers in Table 2 offer SDKs to create Android and iOS apps, but some are available at a nominal fee, while others are quite expensive. When comparing prices, you should know all platforms that you intend to support, and how you intend to support them (app or browser). Then you should price out each module or service required to get that done, plus minimum monthly fees and per-license costs. Remember to factor in the potential storage costs as well.

The Player Side

As a final note, if you're using an off the shelf (OTS) player like JW Player, understand that it may not currently support all DRMs. As an example, the only DRMs JW Player supports for DASH playback are Widevine and PlayReady. So check with your OTS player developer to determine which DRMs it supports.

In addition, before choosing a DRM provider, ask if your player developer has relationships with any providers will simplify the integration. For example, JW Player has partnerships with Vualto and BuyDRM for each provider's multi DRM protocol. Similarly, if you use castLabs' DASH Everywhere DASH Player, sister company DRM Today is a natural DRM provider. Finally, if you'll be creating apps for mobile platforms, check which of your candidate suppliers offer software development kits (SDKs) to speed their development.

Author’s note: The author wishes to thank Christopher Levy, CEO of BuyDRM, for technical assistance with this article.

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