Oppo 95 HDCD playback over HDMI, does it work?

[Owen Smith]

Trying to play HDCD Sampler Volume 2 on my Oppo 95 connected over HDMI to Arcam AVR31. HDCD lights up on the Oppo front panel, but the TV display for the Oppo still says 44.1kHz 16 bit and I thought HDCD is 20 bits. Unfortunately the AVR31 only tells me the sample rate not bit depth.

 

[H.A.L.]

Be sure to have the right hdmi cable for the tv as far as speed goes. I was having trouble with my Oppo and my tv needed a faster eARC hdmi cable than I was using. The tv might be the limiting factor here, though, and not the cable speed.

 

[4-earredwonder]

Trying to play HDCD Sampler Volume 2 on my Oppo 95 connected over HDMI to Arcam AVR31. HDCD lights up on the Oppo front panel, but the TV display for the Oppo still says 44.1kHz 16 bit and I thought HDCD is 20 bits. Unfortunately the AVR31 only tells me the sample rate not bit depth.

When I poised this question a few years back, a QQ poster informed me that even though it doesn't display 20 bit on the screen it is internally decoded as 20 bit.

OTOH, when I play an MQA CD it initially shows up as 16/44.1 on the screen but if I push the display button it definitely shows 24b/88.2 kHz on the screen!

 

[Owen Smith]

When I poised this question a few years back, a QQ poster informed me that even though it doesn't display 20 bit on the screen it is internally decoded as 20 bit.

Thanks. I just wish my AVR would tell me the bit depth. Hang on, I can run the output of my 95 into my 203 and select HDMI in and that might display more information.

OTOH, when I play an MQA CD it initially shows up as 16/44.1 on the screen but if I push the display button it definitely shows 24b/88.2 kHz on the screen!

That must be on an Oppo 205, that's the only model with MQA decoding. And the 205 does not decode HDCD.

 

[Owen Smith]

Be sure to have the right hdmi cable for the tv as far as speed goes. I was having trouble with my Oppo and my tv needed a faster eARC hdmi cable than I was using. The tv might be the limiting factor here, though, and not the cable speed.

The route is Oppo 95 to Arcam AVR31 and then to TV. The Arcam sees the audio before the TV has anything to do with it, with no ARC or eARC involved. And the HDMI leads are 4K rated.

 

[4-earredwonder]

Thanks. I just wish my AVR would tell me the bit depth. Hang on, I can run the output of my 95 into my 203 and select HDMI in and that might display more information.

That must be on an Oppo 205, that's the only model with MQA decoding. And the 205 does not decode HDCD.

Owen, I have 5 OPPOs, four of which are HDCD compatible and none of them display the 20b resolution on any video monitors! It's decoded internally!

As long as the player's HDCD light comes on ... you're getting 20 bit resolution!

 

[Owen Smith]

Owen, I have 5 OPPOs, four of which are HDCD compatible and none of them display the 20b resolution on any video monitors! It's decoded internally!

As long as the player's HDCD light comes on ... you're getting 20 bit resolution!

My concern is that you only get the 20 bit resolution if using analogue out from the Oppo, and not over coax/optical/HDMI which is how I am using it.

 

[4-earredwonder]

My concern is that you only get the 20 bit resolution if using analogue out from the Oppo, and not over coax/optical/HDMI which is how I am using it.

This info may possibly help answer your query, Owen:

https://www.head-fi.org/threads/hdc...-hardware-decoding-and-digital-output.357621/

 

[Owen Smith]

This info may possibly help answer your query, Owen:

https://www.head-fi.org/threads/hdc...-hardware-decoding-and-digital-output.357621/

Doesn't mention Oppo 95 or 93 anywhere, only deals with much older models and I don't think we can assume they work in the same way. It depends whether HDCD decoding is done in the CPU or the DAC and that could change from model to model.

 

[mandrix]

16 bit 44.1 kHz is the CD standard, is it not?
Regardless, the specification can not be exceeded, no matter what hocus pocus wording is used.

 

[mandrix]

What does the decoding should make no difference as long as it's bit for bit. I guess a playback mechanism could introduce extra bits but I don't see the point as it will not introduce more resolution to a 16 bit signal.
If you can prove me wrong, I'll hear what you have to say.

 

[Owen Smith]

16 bit 44.1 kHz is the CD standard, is it not?
Regardless, the specification can not be exceeded, no matter what hocus pocus wording is used.

HDCD encodes extra information in the lowest bits of the 16 bits. When played as a CD that comes out as low level noise which is intended to be inaudible. When decoded and played as HDCD that produces 20 bit 44.1kHz with some other extensions as well, like the ability to exceed 0db without clipping.

https://en.wikipedia.org/wiki/High_Definition_Compatible_Digital

 

[mandrix]

Yep I've read it all before. Encoding "extra information" in the lower bits. It's still 16 bit.
We'll agree to disagree, to me it's just more mumbo jumbo like gold platters and XRCD.

 

[Owen Smith]

Yep I've read it all before. Encoding "extra information" in the lower bits. It's still 16 bit.
We'll agree to disagree, to me it's just more mumbo jumbo like gold platters and XRCD.

But it's not though. It's either (to create a fictitious example) 14 bits with noise when played as CD, or if decoded properly 20 bits. CD is uncompressed, but lossless or lossy (I don't know which HDCD uses) compression can get more data in the stolen bits hence getting to 20 bits. The one thing HDCD is never is 16 bits of actual audio.

 

[Owen Smith]

Here's some actual information on HDCD encoding:

https://wiki.hydrogenaud.io/index.php?title=High_Definition_Compatible_Digital

It doesn't work how I thought, it's more of a sliding window moving the 16 bits of amplitude available on a CD up and down depending on content. Peak Extend in particular adds range at the loudest points, and without an HDCD decoder the audio plays back like a limiter has been used. At the other end for quiet stuff there's just a sliding amplitude window of 6db.

For all the secrecy originally around HDCD, it's not disimilar to NICAM digital sound on UK analogue broadcast TV. That had 10 bits of data at 32kHz sampling rate but with a sliding amplitude window that gave 14 bits of dynamic range with 10 bits of detail. It sounded remarkably good and needed half the bit rate of CD. https://en.wikipedia.org/wiki/NICAM

 

[4-earredwonder]

One thingy I do know: Professor Johnson of Reference Recordings fame was a co inventor of HDCD and he still to this day produces CDs with HDCD encoding!

 

[Owen Smith]

One thingy I do know: Professor Johnson of Reference Recordings fame was a co inventor of HDCD and he still to this day produces CDs with HDCD encoding!

That's exactly the HDCD sampler disc I have. I'm just experimenting to see how they play back on the equipment I already own.

 

[mandrix]

That's exactly the HDCD sampler disc I have. I'm just experimenting to see how they play back on the equipment I already own.

Well if you hear a difference, do tell us. But I think that will be a forgone conclusion. No offense, Owen; not picking a fight.
Over the years I've read about HDCD (I own some still, presumably) and about SBM, or super bit mapping.
I understand what I've read, although there are some vagaries in the explanations of the workings: disagree there's any improvement in sound.
It's all good. We like what we like.

 

[Owen Smith]

Well if you hear a difference, do tell us. But I think that will be a forgone conclusion. No offense, Owen; not picking a fight.
Over the years I've read about HDCD (I own some still, presumably) and about SBM, or super bit mapping.
I understand what I've read, although there are some vagaries in the explanations of the workings: disagree there's any improvement in sound.
It's all good. We like what we like.

Oh I'm pretty certain I won't hear a difference.

 

[SeeMoreDigital]

For anyone who's interested, here's a link to a discussion over on the Doom9 Forum regarding an 'HDCD Software Decoder'...

Link: https://forum.doom9.org/showthread.php?t=129136