Originally Posted by
fat-tony
@adm - I've done some more experimenting with settings. I have a Quad Plus as well as the MB Twin. On the Quad Plus I still can't get uncompressed multichannel INPUT to play properly over HDMI. I get two channels of output being played back as 48kHz PCM streams. I guess more work is needed with the drivers etc. But this is sort of specific to my particular situation where I have multichannel FLAC sound files, so maybe ignore this for the moment.
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Also, on the Quad Plus, but not on the MB Twin, you get the menu option to transcode AAC bitstream to Dolby, so you could use this to pass a transcoded DD 5.1 bitstream over S/PDIF, presumably. So, in your case you could keep your existing AV amp, but would need to upgrade from the MB Twin to a Quad Plus or similarly equipped STB. I presume it's a limitation of the chipset or drivers.