My solution for using a 4k projector with HD621 surround sound is to split the 4k output of my compatible UHD disc player with one HDMI signal going directly to projector input #1 and the other to a HDMI switch.

This Oppo player has a separate HDMI audio output for the HD621.

Then I use the switch to add other 4k/UHD sources, such as Apple TV (which do not output TrueHD or DTS-HD), with an audio extractor after the switch in the chain to feed projector input #2. The extractor supplies SPDIF into a coax input on my surround processor, while the HD621 connects to its (discrete) multichannel input.

Last edited by OldDogCan; 2019-12-04 02:57.
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