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Reply To: [Solved] Apple TV 4K eARC Audio Dropouts with Soundbar / AVR on Apple TV 4K: How to resolve HDMI 2.1 eARC bandwidth handshake failure and Dolby Atmos MAT audio payload truncation
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Home › Forums › HomeKit, Apple TV & Smart Home › [Solved] Apple TV 4K eARC Audio Dropouts with Soundbar / AVR on Apple TV 4K: How to resolve HDMI 2.1 eARC bandwidth handshake failure and Dolby Atmos MAT audio payload truncation › Reply To: [Solved] Apple TV 4K eARC Audio Dropouts with Soundbar / AVR on Apple TV 4K: How to resolve HDMI 2.1 eARC bandwidth handshake failure and Dolby Atmos MAT audio payload truncation
Joan ChenReplacing 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.