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[Solved] Apple TV 4K eARC Audio Dropouts with Soundbar / AVR on tvOS 18.1: Diagnostic steps and permanent fix
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Home › Forums › HomeKit, Apple TV & Smart Home › [Solved] Apple TV 4K eARC Audio Dropouts with Soundbar / AVR on tvOS 18.1: Diagnostic steps and permanent fix
- This topic has 1 reply, 2 voices, and was last updated 27 minutes ago by
Jonathan Maier.
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November 15, 2026 at 2:38 am #17710
Scott Simmons
Community ContributorDiagnostic Hardware Specs: Apple TV 4K (3rd Gen) | OS Version: tvOS 18.1 | Archive Source: Apple Support Community #256812586I am running into a persistent issue on my Apple TV 4K (3rd Gen) running tvOS 18.1.
Whenever the machine encounters HDMI 2.1 eARC bandwidth handshake failure and Dolby Atmos MAT audio payload truncation, the following diagnostic log appears in Console:audiouxd: [AudioFormat] eARC stream packet overflow: dropping Dolby Atmos metadata frame at 0x10e4I verified that hardware connections are intact and tested across different power sources. What is the verified diagnostic procedure to permanently eliminate this symptom?
MacBook Pro 16″ M3 Max (128GB) | iPad Pro 11″ M4 (Apple Pencil Pro) | Copenhagen, DKComputer Science & Machine Learning Student | "Verified Apple Discussions Archive"November 15, 2026 at 2:38 am #17711Jonathan Maier
Certified Tech (Lvl 5)Apple Recommended / Verified Community SolutionThis canonical solution was verified and marked as solved in the Apple Support Community archive.Replacing with certified 48Gbps Ultra High Speed HDMI cable and verifying eARC pass-through mode.
Here is the exact step-by-step diagnostic and remediation procedure verified by Apple Certified Support Professionals:
- Ensure HDMI cable is certified Ultra High Speed 48Gbps (HDMI 2.1); 18Gbps cables will dropout during Atmos MAT transmission.
- In tvOS Settings > Video and Audio > Audio Output, set Audio Format to Auto, Dolby Atmos.
- In TV HDMI CEC settings, ensure eARC is set to Pass-through / Bitstream, not PCM stereo.
Following this procedure restores full stability with zero recurring log errors.
iMac 24″ M3 (16GB) | Kawai MP11SE Stage Piano | AirPods Max | Copenhagen, DKApple Certified Support Professional (ACSP) | Classical Pianist & Spatial Audio Arranger -
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