Yes, the Play does pass-through DTS-HD.
However, there appears to be misconception about DTS-HD pass-through on the SMP/HUB.
The reason that the SMP/HUB can’t pass-through DTS-HD is because they are under the DTS license, but not not DTS-HD license. So the reason that WD can’t implement DTS-HD pass-through, even through it doesn’t require a license to do so, is because if they did it would affect the DTS license. Meaning if WD implemented DTS-HD pass-through, they would lose their DTS licensing. The only way to have both (DTS & DTS-HD) is to be licensed for both, and without the DTS licensing the SMP/HUB could not downmix which would affect people who don’t have a AVR or other device that could decode those audio types.
The reason that the Play can pass-through DTS-HD (also DTS & TrueHD) is because it doesn’t have a DTS license to compromise. Also the reason for this is because the Play is not meant to be a local file steamer. Although it can and does play local files, it’s main function is as a Online content streamer.
