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[Awesome Donkey]

Matt, did anything come from HDCD support you mentioned here: https://yabb.jriver.com/interact/index.php/topic,105378.msg734446.html#msg734446

I tried searching to changelogs but haven't seen anything pertaining to HDCD support. I'm asking because I actually have a couple HDCD rips from the two HDCD CDs I own. I know it's pretty much a dead format, but I'm still curious.

[PGibby]

I can confirm it works in wav, flac...or any other lossless format as long as the dithering settings are correct, and volume is at 100%. The HDCD lamp lights on my dac with that all set.

Interestingly, CDs off of Tidal still have HDCD encoding if the original album did too.

[dtc]

Does it show as 24/44 in Audio Path and does Audio Path report the decoding?

[PGibby]

Does it show as 24/44 in Audio Path and does Audio Path report the decoding?

That I can't tell you at the moment...I won't be by all my equipment for a week or so. I'm pretty sure audiopath has always said 16/44 and does not show any HDCD decoding. As long as its set to wasapi, jriver bit exact dithering, volume at 100%, and there's no DSP being applied....I'll get the HDCD light to light up on my DAC. As soon as a touch anything, for example...drop volume to 99%, the light turns off.

My DAC does HDCD internal decoding...so maybe that wasn't the original question? Were you wondering if JRiver was doing the decoding?

I'll be happy to test whatever you need once I'm back.

[dtc]

Yes, I think the issue is having MC do the decoding, for people whose DACs do not decode HDCD. I know Matt worked on the public domain code, but  I am not sure it even got implemented. 

If your light is on, then MC is not doing the decoding. It is just sending the bit perfect 16/44 with the HDCD encoding still in it. If MC does the decoding it would send 24/44 and the light would not come on, since the decoding has already been done.

I used dBpoweramp to do the HDCD decoding, so my files are 24/44.

[PGibby]

Ah yes, that's what I suspected. My stuff is so old, I didn' know HDCD was really still a thing. Besides the Reference Recordings label, I don't know of anyone else doing HDCD releases anymore (besides the random surprises).

[Ripman]

You can use eac3to with the -hdcd option to decode into 24/44.1 wav or flac - the output file will no longer have the HDCD encoding embedded, and you can import this directly into MC. eac3to will give you an average bit-depth when completed.

I have 15 to 20 HDCD’s, and the highest bit-depth I’ve seen is 18 bit average for the Reference Recordings CDs. Even the Audio Fidelity 24k CDs only average 17 bit.

[weirdo12]

I can confirm it works in wav, flac...or any other lossless format as long as the dithering settings are correct, and volume is at 100%. The HDCD lamp lights on my dac with that all set.

For the record, if Volume Levelling and/or Adaptive Volume are enabled then HDCD will not be detected by an HDCD capable DAC.

Also, CD's ripped using dbPoweramp's HDCD DSP must have the +6dB Amplification setting checked or HDCD will not be detected.

[RD James]

Also, CD's ripped using dbPoweramp's HDCD DSP must have the +6dB Amplification setting checked or HDCD will not be detected.

If dBpoweramp is decoding the HDCD data to a 24-bit file, it seems like the DAC should not be detecting the track as HDCD, otherwise the processing will be applied twice.

[weirdo12]

If dBpoweramp is decoding the HDCD data to a 24-bit file, it seems like the DAC should not be detecting the track as HDCD, otherwise the processing will be applied twice.

And to add to your observation, on my Berkeley Alpha DAC, if the filter is set to 24-bit - no HDCD detection. It has to be set 16-bit and that is stated in the manual.

[weirdo12]

If dBpoweramp is decoding the HDCD data to a 24-bit file, it seems like the DAC should not be detecting the track as HDCD, otherwise the processing will be applied twice.

Now that I have the Alpha DAC that can decode HDCD, I think I need to just rip a HDCD using JRiver or EAC instead of using dbPoweramp and the DSP and check the results!

[RD James]

Now that I have the Alpha DAC that can decode HDCD, I think I need to just rip a HDCD using JRiver or EAC instead of using dbPoweramp and the DSP and check the results!

The only problem with that, is that you can't apply DSP to it or it will break HDCD playback.
If you decode the HDCD data to a 24-bit file, you can apply DSP without losing the extra dynamic range.

[weirdo12]

I ripped History Of The Grateful Dead, Vol. 1 from The Golden Road box using JRiver 24. The resulting files are 44.1/16.

Analyzing was turned off during the ripping process although they did get analyzed during import. This is a does not modify the audio file and as expected it has no detrimental effect on playback.

The Alpha DAC (with the 16-bit filter) recognizes them as HDCD (the HDCD LED lights up) as long as the volume is at 100%. Again, Volume Leveling and Adaptive Volume also affect HDCD detection.

[weirdo12]

If dBpoweramp is decoding the HDCD data to a 24-bit file, it seems like the DAC should not be detecting the track as HDCD, otherwise the processing will be applied twice.

If files are created with dBpoweramp using the HDCD DSP you *must* have the +6dB setting on or the Alpha DAC does not recognize them as HDCD.

[RD James]

If files are created with dBpoweramp using the HDCD DSP you *must* have the +6dB setting on or the Alpha DAC does not recognize them as HDCD.

My point is that the DAC should not be recognizing them as an HDCD track if dBpoweramp has already converted them to 24-bit.
It should only be recognizing files as HDCD if you play the unconverted 16-bit track.

[weirdo12]

My point is that the DAC should not be recognizing them as an HDCD track if dBpoweramp has already converted them to 24-bit.
It should only be recognizing files as HDCD if you play the unconverted 16-bit track.

Understood and I agree. Although, as I said earlier, the DAC is only seeing HDCD if it's filter is set 16-bits. If you change the filter to 24-bits then HDCD is not detected.

[RD James]

Although, as I said earlier, the DAC is only seeing HDCD if it's filter is set 16-bits. If you change the filter to 24-bits then HDCD is not detected.

I'm not sure that I understand. Are you converting the tracks with dBpoweramp's HDCD decoder enabled to a 16-bit output?
The whole point of HDCD decoding is that it expands from 16-bit to 20-bit (which means being placed inside a 24-bit container).

[weirdo12]

The whole point of HDCD decoding is that it expands from 16-bit to 20-bit (which means being placed inside a 24-bit container).

Yes, that's correct. What I'm reporting is specific to the Berkeley Alpha DAC and it might be useful to someone who owns one.

[weirdo12]

I'm not sure that I understand. Are you converting the tracks with dBpoweramp's HDCD decoder enabled to a 16-bit output?

The answer to this question is - no - it's 24-bit.

[RD James]

Yes, that's correct. What I'm reporting is specific to the Berkeley Alpha DAC and it might be useful to someone who owns one.

But if you're decoding the HDCD data in software, the DAC has nothing to do. It's already been decoded.
Since it has been decoded, the DAC should no longer see it as an HDCD track - just a 24-bit audio track.
 
If you're doing something which decodes the track and causes the DAC to still see it as an HDCD track, something has gone wrong.
I suspect that HDCD decoding is supposed to reduce the volume level of the track, but dBpoweramp's +6dB option restores the original volume - so even though the track has been decoded, the DAC still detects it as an undecoded HDCD track.
 
Testing against the stand-alone HDCD converter, the checksum does not match if dBpoweramp's +6dB option is enabled.
With the +6dB option disabled, the output file is a match.
 
I don't know why they added that option, but you probably shouldn't be using it.

[weirdo12]

Testing against the stand-alone HDCD converter, the checksum does not match if dBpoweramp's +6dB option is enabled.
With the +6dB option disabled, the output file is a match.

Of course, that is the expected result of that comparison. BTW, does 'stand-alone HDCD converter' refer to hdcd.exe?

[RD James]

Of course, that is the expected result of that comparison. BTW, does 'stand-alone HDCD converter' refer to hdcd.exe?

Yes

[weirdo12]

I don't know why they added that option, but you probably shouldn't be using it.

Before I investigate, do you know a reliable way to truncate a 24-bit file to 16-bit?

[RD James]

Before I investigate, do you know a reliable way to truncate a 24-bit file to 16-bit?

Certain audio editors can do it. iZotope RX has that option.
I think Media Center can even do it if you disable dither before conversion, but I have not tested to see if that output matches the result I get from RX.
If what you're thinking is to enable the +6dB option, truncate it to 16-bit and see if it matches the source file, I tested that and it does not.
 
I've looked into it a bit more, and it seems that decoding HDCD tracks automatically reduces the volume by 6dB. This is to provide additional headroom for the Peak Extend feature that some discs may use.
The +6dB is to restore the original volume level before HDCD decoding - however it does not account for the Peak Extend feature, so if the disc uses this, the track may be pushed to clipping with the +6dB option enabled.
I have tested this with one of my HDCD discs that has Peak Extend enabled, and it was indeed pushed to clipping with dBpoweramp's +6dB option enabled.
 
Since dBpoweramp does not account for this, and since I always analyze tracks and use Volume Leveling in Media Center anyway, I see no reason to ever enable the +6dB option during conversion.
Without using Volume Leveling, at best it makes tracks a bit louder, at worst it pushes tracks to clipping.

[weirdo12]

If what you're thinking is to enable the +6dB option, truncate it to 16-bit and see if it matches the source file, I tested that and it does not.

That's what I was thinking.

[weirdo12]

Certain audio editors can do it. iZotope RX has that option.

I found that GoldWave (v6.32 which I already owned) can do what I wanted to do.

If what you're thinking is to enable the +6dB option, truncate it to 16-bit and see if it matches the source file, I tested that and it does not.

I did just that (I did not compare checksums) and playing back the file with JRiver or GoldWave activates the HDCD LED on the Alpha DAC.

 

I've looked into it a bit more, and it seems that decoding HDCD tracks automatically reduces the volume by 6dB. This is to provide additional headroom for the Peak Extend feature that some discs may use.

Most of them are 6 (6.1) but I have seen 4.5 as well.

I'm wondering now how useful the Alpha DAC's HDCD decoding feature is in determining if the data it's receiving is bit-perfect.

If I play back a non-decoded, 16-bit file (one of the files I ripped with JRiver) with JRiver or GoldWave the HDCD indicator is on. If I play a 24-bit dBpoweramp decoded file with the +6dB setting the HDCD indicator is on. If I truncate a 24-bit file created with the +6dB setting with GoldWave and play it back, the HDCD indicator is on. If I play a decoded file without the +6dB, the HDCD indicator is off. Same results with JRiver or GoldWave as the player.

With Foobar and XMPlay (both have WASAPI support installed) I get mixed results that I'll report when I'm at home.

[weirdo12]

With Foobar and XMPlay (both have WASAPI support installed) I get mixed results that I'll report when I'm at home.

In Foobar, the ReplayGain options were on which explains why the only file that indicated it was HDCD was the truncated file that was saved as a WAV file and had not been analyzed by JRiver.

On XMPlay, the volume control was not at 100%.

Anyway, all 4 players now have the identical results when playing back the same set of files.