3SS Insights: Building a Set-Top-Box RDK vs. AOSP vs. Android TV

In recent years Linux/RDK-based set-top boxes (STB) have proven particularly popular among pay-TV operators. The reasons are that they are readily available, the prices are relatively low and they require standard, non-specialist web development expertise. Nevertheless, our industry is constantly changing and any operator considering which technology to choose for their new STB-based (set-top box) service platform needs to stay on top of hardware and middleware technologies as well as tracking Google’s evolving development roadmap.

3SS offers this article as a resource to any operator considering which technology to adopt for their next consumer video entertainment platform. With a raft of announcements from Google regarding new Android TV features, and in a landscape of increasingly frequent Android TV-based roll-outs by operators, the need to understand all the nuances of this topic has become more relevant than ever. Choosing the right operating system and platform for new STB launches is critical for success.


RDK/ Linux based STBs

RDK is a standardized software stack based on Linux with localization plugins. Most Linux based STBs nowadays are in fact aligned with the Royalty free reference Design Kit (=RDK).

RDK is driven by Comcast and is geared exclusively for operators wanting to launch STB-based services for consumers.

RDK sits below the MVPD (multichannel video programming distributor) application and services layer and provides a common interface to the hardware system, acting as a universal System-on-a-Chip (SoC) adapter. In addition, this standardized stack provides a common method to manage complex video functions such as tuning, conditional access, DRM, and stream management.

Over the last few years (SoC) chipsets have become powerful enough to run a complete browser stack on Linux STBs, now considered the standard development environment for UIs with the breakthrough of HTML5 and JavaScript. As a logical consequence, a platform’s frontend is now typically developed using modern web techniques – theoretically enabling any web-developer to develop UI applications on RDK. But the SoC comes with advantages and disadvantages.

On one hand, development is easier as today’s industry has an abundant supply of talented web developers. However the resource limitations of SoC-based STBs, as well as the rather limited range of available complementary apps, should also be considered. By default, unlike with Android TV, with the RDK approach there is no app-store available and therefore this needs to be sourced by the operator. In terms of control, and choice, it is wise to keep in mind that middleware development is usually exclusively controlled by the STB vendor, and therefore the supplier of this hardware is a significant stakeholder over the long term.


A Tale of Two Androids – Diving Deep into AOSP vs Android TV

AOSP based STB

AOSP (Android Open Source Project) is Android’s source code based on Linux itself.

If choosing AOSP, you do not get any additional proprietary blobs from Google such as:

  • Google First Time Install Wizard
  • Google Mobile Services / Google TV Services
  • Widevine DRM keys and support for DRM
  • Google Play Store
  • Leanback (Android TV Theme)

In other words, AOSP is the pure Android code-base and is also used for mobile versions and for any other Android based platform such as Android Car.

By choosing AOSP, however, you benefit from all the UI libraries and capabilities in the Android Ecosystem. Apps are developed with Android SDK/Java with unrestricted access to system resources, enabling high performing UIs and easy interaction with hardware and middleware.

By having full control over the AOSP-based system, the operator must take full responsibility for platform management and development. This approach introduces the need to devise and deploy additional elements, independent from Google, posing numerous variables which add complexity, require additional decision-making and more ‘in-house’ resource to manage the system to a high quality standard.

Additionally, it is vital to understand and manage the interaction between middleware and hardware tuners (e.g. DVB) and DRM protected playback.


Compared to Android TV, with AOSP the majority of functionality and capabilities need to be self-sourced, developed or purchased through middleware. All of this means far greater development effort is needed on the part of the operator, as well as management of ongoing maintenance, future system enhancements, etc.

AOSP – The Pros AOSP – The Cons
  • Complete control
  • Regular updates with new features and enhancements from Google
  • Utilization of Android ecosystem
  • Allows faster and better performing UIs and applications in general thanks to direct access to hardware resources
  • No Widevine out of the box
  • No App-Store (Google Play)
  • No Netflix without certification
  • No proprietary third party drivers or hardware support
  • Need for more intensive middleware development by STB vendor
  • Higher hardware requirements
Risks when using AOSP

  • Major upgrades by Android/Google may compel work and investment by operator
  • No integrated app eco-system or app store


Android TV

Android TV is the name for a complete build of the AOSP firmware including all of Google’s proprietary enhancements. The biggest benefit of Android TV however is that it is part of a much bigger ecosystem, one which is currently the pre-eminent operating system in the world, at least based on market figures.

Figure 1: Android overtakes Windows as most popular OS (Source: http://gs.statcounter.com/press/android-overtakes-windows-for-first-time)

Android TV includes all proprietary additions and completions absent from AOSP such as:

  • Google First Time Install Wizard
  • Google Mobile Services (now Google TV Services for TV)
  • Widevine DRM keys
  • Google Play Store
  • Google Search and Assistant (enabling voice control)
  • Leanback (Android TV Theme)


Google significantly eases the go-to-market process with Android TV, and continually rolls out new features. With several reference designs with major SoC suppliers, the certification process with google and also Netflix can be expedited – which is a huge plus as this ensures quick time-to-market. However, the operator or service provider using Android TV must strictly comply with Google’s many requirements to be certified. This means the operator ultimately has less control over the overall project since it is effectively co-driven by Google’s Compatibility Definition document. Furthermore, Google’s requirements can change over time, so the operator needs to be vigilant as regards new requisites, and needs to be nimble and capable enough to understand, embrace and deploy the changes to ensure compliance. Google has taken steps towards operators and pay-tv providers, offering the “operator tier” which l– besides a few requirements for visibility of apps and usage of google assistant starting with Android O (the latest version) – does give complete control and freedom over the launcher UI, effectively taking away one of the biggest fears and concerns that existed towards Android TV. At the time of writing google also announced to reduce the minimum hardware requirements for Android TV with Android O on TV.

Android TV – The Pros Android TV – The Cons
  • No drivers or middleware required on certified hardware
  • Netflix out of the box
  • Reference UI + Leanback framework
  • Regular updates with new features and enhancements
  • Unrestricted utilization of Android ecosystem
  • Allows fast performing UIs and applications in general via more direct access to hardware resources
  • Certification by Google required
  • Compliance with CDD (incl. “timely” upgrades to major versions)
  • Needs to include and support Google’s Android Ecosystem
    (Google Play app-store, 3rd party channels addition option to EPG, Global search, etc.)
  • Highest hardware requirements
Risks when using Android TV

  • Google has persistent control
  • Dynamically changing compliance requirements must be expected over time


Cost of Ownership Comparison

(based on comparative hardware requirements, development efforts and technical expertise)

Cost of ownership Linux based/ RDK AOSP Android TV
Hardware Lower ­ High ­ High
Middleware ­ High ­ High Medium
Development ­ High Medium Lower

Table 1: Cost of ownership comparison


Table 2: RDK vs. AOSP vs. Android TV (GTVS)



Each platform STB technology – Linux based RDK, AOSP or Android TV – has its advantages and disadvantages. The operator or service provider should make its final decision based on the priorities defined for the project.

Regardless, there is a very clear market trend towards basing a TV service ecosystem on Android TV:

Its usability and feature set are continually and rapidly improved by Google. Also, Google is opening up its Android TV platform to enable much more customization via the so-called Operator Tier which even allows an operator to substitute the Android TV Launcher with a customized alternative which can be designed completely independent from Android TV UI design.

In addition, engaging new apps are always being added to the official Android TV platform whereas on AOSP, a distribution mechanism like an App Store is required to launch new apps for your subscribers. This also means that with AOSP, the operator needs to manually populate its app market or it must identify and integrate an alternative to the Google Play Store.

3 Screen Solutions is happy to help any operator navigate the many complexities and interconnected factors than need to be considered in making the all-important decision of choosing the underlying technology for a pay-TV platform.

We offer world-class consulting, advisory and services for planning, integrating and deploying overall project architecture.

We are always happy to explore and discuss the benefits of considering 3SS as your development partner of choice for ongoing implementation. Please get in touch with us at contact@3ss.tv and together we can scope the ideal platform for you and your subscribers.

Author: Martin Basgier, www.3ss.tv

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