Developer creates open-source Dolby TrueHD Atmos workaround for Apple TV 4K
A Reddit user devised a method to play lossless Blu-ray audio on Apple TV 4K by converting data to Apple's proprietary spatial format.
Key points
- The workaround converts Dolby TrueHD Atmos to Apple Positional Audio Codec for playback.
- The project aims to replace closed-source Native Player with an open-source alternative.
- Users must currently build the Nuvio media client extension themselves on a Mac.
A developer known as Agathorpt has created a method to deliver lossless Dolby TrueHD audio with Dolby Atmos effects to the third-generation Apple TV 4K. According to TechRadar, this achievement utilizes the Nuvio media client and requires users to build the feature manually on a Mac computer.
The solution addresses a limitation in Apple’s hardware, which officially supports only the compressed Dolby Digital Plus codec. While Dolby Digital Plus is standard for streaming services to reduce data usage, Blu-ray discs use the higher-bandwidth TrueHD format. This new approach allows enthusiasts to play TrueHD files on their Apple TV devices, bypassing the official restriction.
Technical Implementation Details
The system does not transmit TrueHD audio directly to the speakers. Instead, it decodes the TrueHD Atmos stream into separate audio and timed object metadata components. The process then maps the 3D Atmos positioning data to a fixed 9.1.6-channel speaker configuration.
After mapping the channels, the system converts the audio into Apple Positional Audio Codec, or APAC. This proprietary format allows the processed audio to be played natively through tvOS. Although APAC is not a lossless format like the source TrueHD, TechRadar reports that the resulting audio quality is considered impressive by users.
The complete signal path moves from TrueHD Atmos to decoded audio and metadata, then to a fixed speaker render, into APAC, and finally to native tvOS playback. This complex conversion chain enables the Apple TV 4K to output high-quality spatial audio that it could not handle in its original TrueHD container format.
Open Source Motivation
Agathorpt developed this workaround to replicate the functionality of Native Player, a closed-source application that already supports similar audio features. The primary goal was to create an open-source alternative that does not rely on a single vendor for maintenance or future support.
"Keeping the implementation closed… leaves everyone dependent on that vendor for fixes and future support," Agathorpt stated. The developer noted that other players cannot reuse or improve closed code, and the community cannot independently inspect how the audio is handled.
Early testing by Agathorpt and other Reddit users has yielded positive results. Agathorpt reported that the spatial audio works amazingly well on their setup, describing the sound as excellent. Other community members who tried the software also reported great results, validating the technical approach.
What should you do?
Users interested in this feature should assess their technical comfort level, as the current solution requires building the software on a Mac. Those relying on closed-source apps for similar functionality may want to monitor the Nuvio project for easier installation methods.
What to do and how to stay safe: Apple TV 4K
- Check if your Apple TV 4K is the third-generation model, as this is the specific hardware targeted by the current workaround.
- Verify that you have a Mac computer available, since building the Nuvio extension currently requires macOS development tools.
- Monitor the Nuvio media player repository for updates that might simplify the installation process for non-technical users.
- Review your home theater speaker configuration to ensure it can support the 9.1.6-channel mapping used in the conversion process.
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Frequently asked questions
Does Apple TV 4K officially support Dolby TrueHD?
No, the Apple TV 4K officially supports only Dolby Digital Plus, which is a compressed codec used for streaming services.
Is the audio quality lossless in this workaround?
No, the final output uses Apple Positional Audio Codec, which is not lossless, though users report the quality is impressive.
Can I install this feature easily on my Apple TV?
Currently, no. Users must build the feature themselves on a Mac, as it is an extension to the Nuvio media client.
