decoding HDMI audio : DM8147 or DM8148 ?

[SoNic_real_one]

HDMI requires encryption of all the signals with HDCP. The cips are not available for DIY because require signing some NDA (by a company).
HDMI is interleaving video with audio, is not ment for audio quality. The main aspect that was looked into when they designed HDMI was the security of digital signals. Audio quality of HDMI transmission chain sucks, regardless what marketing propaganda say.

And, no, none of the above chips will decode digital audio, they just "incapsulate" existing SPDIF or DSD. Decoding (extracting from compressed and/or protected signals) of those needs to be done in some other chips.