tl,dr: How Collabora partnered with the YouTube Cobalt and Device Partner Engineering teams to deliver the first RDK-based reference platform for their next-generation living room web engine.

Switch on your Smart TV, open YouTube, and navigate to Settings → App Version, you might spot a version text like 25.lts. That’s the version of classic Cobalt, the lightweight, open source HTML5/CSS/JavaScript engine meant specifically for resource-constrained embedded devices, which currently runs YouTube on living room devices such as SmartTVs, STBs, etc.

Over the years, Cobalt has undergone a massive architectural transformation: the transition from classic Cobalt to Chrobalt, (Cobalt re-architected on top of Chromium).

At Collabora, as we continue our journey to accelerate, collaborate, and adopt open source, we have been working closely with Google's YouTube Cobalt and Partner Engineering teams to deliver the first-ever RDK-based Chrobalt reference platform for third-party devices, proving this major architectural evolution for device partners and OEMs worldwide.

The Shift: From Cobalt to Chrobalt

Historically, running a full-fledged browser engine like Chromium on low-power set-top boxes (STBs) and Smart TVs was out of the question due to tight RAM and CPU constraints. Google built Cobalt from the ground up to solve this exact problem, offering a minimal web standards subset optimized for media streaming and lean resource consumption. Cobalt interfaced with hardware platforms through an abstraction layer called Starboard, allowing OEMs and SoC vendors to port YouTube to custom silicon.

However, maintaining an independent layout and rendering engine alongside the rapidly evolving modern web ecosystem is a massive undertaking.

To bridge this gap, Google initiated a bold engineering effort: Merge Cobalt’s code with Chromium to get a robust, standard-compliant rendering pipeline.

The result is Chrobalt (starting with 26.eap and recently updated to 27.lts, tracking modern Chromium milestones like 138+). Now Chrobalt is a Chromium embedder with a Starboard porting layer.

Thus Chrobalt combines the best of both worlds:

• Modern web features and rapid web security updates from upstream Chromium.
• Starboard integration and low-footprint media pipelines tailored for TV and STBs hardware.

There are reference ports for Desktop and Android, but the story is incomplete without providing some reference port for external device manufacturers to convince them about Chrobalt \- So here we are.

Collabora’s Role: Building the RDK Reference Platform

For over a year, we engaged directly with Google’s YouTube Cobalt team and partner engineering team to port, integrate, and stabilize Chrobalt on an RDK (Reference Design Kit) platform for Amlogic chipsets, establishing the foundational reference design for Google’s device partners such as Samsung and LG.

We drove the full lifecycle of integration and validation:

1. Starboard & Toolchain Modernization: Decoupled and restructured legacy Starboard recipes across RDK Yocto layers, modernizing toolchains to support newer C++ standards required by Chromium.
2. Comprehensive Test Suite Integration: Integrated Chromium unit test suites alongside Starboard’s NPLB (No Platform Left Behind) conformance suite to ensure baseline platform compatibility.
3. YTS Certification Enablement: Configured and validated the platform to pass the rigorous YouTube Test Suite (YTS) requirements, ensuring seamless 4K/UHD playback, DRM handling, and low-latency input.
4. RDK Ecosystem & Plugin Integration: Integrated Chrobalt into RDK’s modular plugin architecture (including RDK7 support), ensuring clean lifecycle management, memory sandboxing, and unified audio/video pipeline integration.
5. Upstream Cobalt & Starboard Contributions: Identified and upstreamed critical fixes directly to the Cobalt/Starboard codebase to benefit the broader ecosystem.
6. DAB Adapter & Test Automation: YTS runs are driven over the Device Automation Bus (DAB). Collabora co-authored the Rust reference implementation of DAB (dab-adapter) and contributed to the DAB Compliance Test Suite. On the Starboard platform we extended and fixed the adapter so the device could be driven reliably and reproducibly through the full YTS run.

Acknowledgement from Google team at BlinkOn-21 Lightning Talks

This April, we also attended the YouTube Device Partner Summit in Japan, where the Chrobalt RDK Reference Platform was officially mentioned to industry partners as a validated, production-ready path forward for next-generation living room deployments.

A special thanks to Denis Shimizu and André Magalhães for their contributions.

Accelerate Your Embedded Web & Living Room Deployments

Whether you are targeting RDK or any custom Linux platform, are curious, or need help running YouTube or Embedded Web using Cobalt/Chrobalt, reach out to us.

How we can help:

• Custom Porting & Starboard Integration: Bring Chrobalt or custom WebEngines to your proprietary SoC or reference hardware.
• YTS Certification & Performance Tuning: Optimize frame rates, input latency, and memory footprint to achieve rapid YouTube and streaming service compliance.
• Web on Embedded system: Chrobalt based Web UI bring up on resource constraint devices, which has been proven with YouTube.
• DAB Adapter Bring-up: With the expertise of having co-authored the DAB reference implementation, we can help you implement the DAB protocol in your living room products, such as TVs, set-top boxes or streaming sticks, binding DAB operations to your platform APIs and taking the device through DAB compliance.

We hope that next time you switch on your Smart TV, open YouTube, and navigate to Settings → App Version, you get to see the latest Chrobalt version 27.lts or later

Links:

BlinkOn talks

Github source repo

Instruction to setup and run on RDK

27.lts.1