Originally Posted by maikeldepotter
I just ran a test with the AIX Audio Calibration BluRay disk using a digital coax cable to connect my Oppo to my external Rega DAC. I played the 96kHz/24bit/2.0 ch. LPCM test track. Every time I start it (or any other track on that disk), the sampling rate indicator on the Rega DAC switches for a split second to 88.2-96 kHz to immediately return to 44.1-48 kHz and stay there.
My preliminary conclusion therefore (until proven otherwise): Sampling rates on Blu-Rays higher than 48kHz/16 bit only have true meaning when the DA conversion happens in the BR player and the analog-outs are used to carry it further.
S/PDIF outputs are handled separately from HDMI outputs, and their ability to output >CD audio depends on the source. If the source is a downloaded PCM file, it is not restricted. If the source is a DVD-A or BD disc using HDCP encryption, then the coax (a.k.a. "legacy digital output") is restricted to "CD-Audio quality or less."
There goes AIX Records' myth that you can enjoy their 96Hz/24bit 7.1 recordings at full resolution using HDMI to connect your player to your processor/receiver: not true, or misleading at the least (to me).
A BD player can merrily output HD audio all day long to external devices connected with HDMI even if HDCP encrypted. The analog audio produced is not restricted in any way. The issue for your DAC is that is that it does not have an HDMI input.
The issue I raise is about an HDMI device that provides non-HDCP digital outputs, be they S/PDIF or AES. As Dan Schulz noted elsewhere
, >>It is a requirement for HDCP encrypted content that it be down-sampled to 48/16 if being output digitally.<< My pure speculation was simply that if the Altitude is truly not capable of SRC, then perhaps that is known to the BD player which takes care of it.
I actually do not believe that an HDMI compliant device can "pass the buck" upstream to the source player, but this was one way to address the alleged fact that the Altitude has no SRC. Perhaps that is an overstatement. Perhaps it is true that the Altitude applies no SRC during its internal audio processing, in contrast with more pedestrian AV processors which do things like downsample to 48 kHz when Audyssey is active, or which run all audio through 96 kHz SRC chips. Even so, it may still be the case that the Altitude limits the AES outputs to "CD-Audio" when playing HDCP content in order to be compliant.
But why speculate. It is easy enough to find out if one has an Altitude and a device that reads sample rate of the AES output. Feed it via HDMI from a DVD-A disc with 96 or 192 kHz audio. Does the Altitude report the disc's sample rate? If so, does it matter if the AES outputs are active or not (assuming they are even switchable)? What is the AES output sample rate?