Originally Posted by wierzbowski
Can someone please confirm that my understanding is correct on HDCD decoding:
1) The BDP-80 (and possibly other BDP models) still do not output decoded HDCD data via HDMI bitstream.
2) If I enable HDCD decoding on the Oppo, I do not use HDMI at all, I do use coax/optical, and I set coax/optical to PCM; then, the Oppo will properly decode HDCD and send 44.1/20 PCM data to my processor.
Almost entirely wrong.
But not to worry as this stuff is confusing.
The BDP-80 *WILL* pass HDCD info in either HDMI or Optical/Coax digital audio for decoding in an AVR that knows how to decode HDCD itself.If you have an AVR that decodes HDCD, and you use it with digital audio from the 80, then you should leave HDCD decoding turned OFF in the 80.
That's because the result of decoding the HDCD matrix leaves enough remnants of the original HDCD in the digital output stream that the decoder in your AVR will get confused into thinking it needs to turn its OWN decoding on. And so the AVR will repeatedly switch in and out of HDCD decoding mode -- which results in audible glitches each time the switch happens.
TECHNICAL NOTE: This is simply an artifact of the design of HDCD. HDCD was invented before digital audio output from home theater players. The assumption was that any HDCD-decoding player would be used with ANALOG audio output, and so the remnants of HDCD still in the digital audio stream after the decode were irrelevant.
If you are sending digital audio to an AVR that does NOT decode HDCD itself, then you can safely turn on decoding in the 80.
To turn on HDCD decoding in the 80 you need to do two things. Set HDCD Decoding ON and set HDMI Audio LPCM. The Optical/Coax setting does not matter.
The result of decoding HDCD is 2.0 LPCM 44.1KHz 20-bit. That is packed into 24 bits for output (with padding zeroes). So the digital output on HDMI or Optical/Coax is 2.0 LPCM 44.1KHz 24-bit.
With HDCD Decoding OFF (or HDMI Audio Bitstream) the output is 2.0 LPCM 44.1KHz 16-bit -- with the HDCD matrix data intact for use by a decoding AVR, or to be ignored by an AVR that plays this as traditional, "CD compatible" digital audio.