What types of multichannel audio file formats exits as of today?
And which harware interface supports which of them?
As far as I know

Multichannel File Formats
.dts
.ac3
.wav (dtswav)
.wav (ac3wav)
.flac (5.1)
.ape (5.1)
.wma (wma pro)
mlp
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Hardware Interface - Allowed/Supported format
Analog - .flac (5.1), .ape (5.1), .wma (wma pro)
S/PDIF - .dts, .ac3, .wav (dtswav), .wav (ac3wav)
HDMI - All Digital

Pls add to it and correct if anything wrong