Not to familiar with HDCD but I know foobar uses a plugin
I was wondering, if I can get the FLAC file "HDCD decoded" when ripping the CD to FLAC in Foobar2000. Meaning - the DAC does not have the capability to decode the HDCD flag. So the FLAC should already have the HDCD encoding. Does Foobar's plugin do that? What does the flag "Enable decode postprocessing - for decoding DTS, HSCD, etc." in Foobar2000 do?
JRiver can decode HDCD. The file just needs to be tagged as HDCD. Use Audio Analyze to do that.
dBpoweramp will decode an HDCD and create a 24 bit file with the HDCD bits decoded. So, when you play it, the blue light on the DAC will not light, since the HDCD bits have already been decoded.
If you DAC decodes HDCD, you should let the DAC do it. The software decoders are attempts to duplicate what the chips in the DAC do, but they do an incomplete job.