HDCD feedback and information thread

[vortecjr]

I have been curious about HDCD for a while. What is your experience with it? 

 

Useful information

 

As for playback software that decodes HDCD:

1. Windows Media Player - decodes HDCD

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

2. JRiver - MC25 decodes HDCD

https://yabb.jriver.com/interact/index.php/topic,119387.0.html

3. XX High End -  decodes HDCD

http://www.phasure.com/index.php?board=1.0

4. Roon - does not decode HDCD

5. FooBar2000 - decodes HDCD

(foo_dsp_hdcd) This DSP component will decode HDCD data in any 16-bit PCM stream passed through it, resulting in 20-bit PCM. Also, has a handy scanner to find all your HDCD content.

6. Audirvana - need to research this

7. HQ Player - need to research this

8. MinimServer - decodes HDCD via ffmpeg.

https://forum.minimserver.com/showthread.php?tid=1502&pid=33528#pid33528

9. any other you can think about let me know

 

As for ripping software that decodes HDCD:

1. DB Power Amp - per manual,

"Depending upon which audio player is used, if the player can handle 24 bit audio files, then adding the DSP effect HDCD is useful, in that any HDCD audio CDs (a special encoded audio CD with 20 bits of encoded audio information) will be detected and encoded to a 24 bit audio file, non HDCDs are left at 16 bit." 

https://www.dbpoweramp.com/cd-ripper-setup-guide.htm
2. Exact Audio Copy - need to research this

3. any other you can think about let me know

 

As for software that decodes HDCDs or find HDCDs in your library:

1. hdcd.exe

http://forum.doom9.org/showthread.php?p=1815788#post1815788

2. libhdcd

https://github.com/bp0/libhdcd/blob/master/README.md

3. FFmpeg

https://ffmpeg.org/ffmpeg-filters.html#hdcd

4. CUETools

http://cue.tools/wiki/CUETools

5. Script for Linux to find your FLAC HDCDs

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

6. any other you can think about let me know

 

Lists of HDCDs:

1. http://www.goodwinshighend.com/music/hdcd/hdcd_recordings.htm

2. https://www.head-fi.org/threads/hdcd-list.65414/

3. https://musicbrainz.org/search?query=format%3Ahdcd&type=release&limit=25&method=advanced

4. https://wiki.hydrogenaud.io/index.php?title=List_of_HDCD-encoded_Compact_Discs

5. any other you can think about let me know

 

Technical Stuff

1. By Jim Web
http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html
http://www.audiomisc.co.uk/HFN/HDCD/Examined.html

2. By Charles Hansen

https://www.audioasylum.com/audio/digital/messages/18/184385.html

[vortecjr]

23 hours ago, mansr said:

Does it still exist? Honest question.

I'm going to assume people are still recording with Pacific Microsonics' gear, but I'm not sure if they are releasing any new content with it. I still have cds with the mark though:)

[vortecjr]

1 hour ago, manisandher said:

 

I owned a Pacific Microsonics Model Two for many years. I played around extensively with the various HDCD processes for 16/44.1, and always ended up preferring no HDCD processing. Above 16-bit, there was no HDCD processing applied by the Model One/Two.

 

When you play an HDCD-encoded 16/44.1, you generally have no idea exactly what HDCD processing was applied. (Hopefully the HDCD.exe decoder in your SW player is smart enough to figure this out, if you're not using a built-in HW decoder in your DAC/CD-player.)

 

For me, the biggest benefit of using HDCD-encoded CDs or files is that they were mastered on a Model One/Two, which was, and still is, a simply superb ADC. 16/44.1 is good, but try getting hold of some 24/176.4 or 24/192 mastered on a Model One/Two. Reference Recordings is the obvious source. The 24/192 of Kind of Blue was created using a Model Two. If there's any way you can play these files back natively (with no filtering or SDM), the sound quality is stunning.

 

HTH.

 

Mani.

My understanding is that you were suppose to get 24 bit playback? I understand you need a device capable of decoding it. I think the Berkeley gear can decode it. I didn't think about Reference Recordings so yes it's still being available. 

[vortecjr]

22 minutes ago, Ralf11 said:

There is a comprehensive thread on this - I posted on it, maybe started it with a question - if you do a search.

 

Upshot - several aspects to HDCD & releases may or may not have used all or some of them - there is a compilation on the web somewhere which describes what had which aspects

 

PM ADC may be the biggest factor re SQ

I'll look for it. I remember something about that issue as well. The compilation should be interesting. Agree on the PM ADC.

[vortecjr]

36 minutes ago, manisandher said:

 

HDCD 16/44.1, I don't think so - I can't imagine why anyone would do use HDCD processing nowadays. But 'HDCD' 24/176.4 or 24/192, definitely. But they're not really HDCD (see previous post).

 

Mani.

I did a search on Amazon and the information is sketchy at best. Reference Recordings seems to be the only new source based on a quick search. 

[vortecjr]

9 minutes ago, Axiom05 said:

If done properly, e.g., Reference Recordings, you can get an extra 6 dB of dynamic range. The Ayre QX-5 Twenty can decode HDCD and I still enjoy my few RR recordings that have never been reissued in Hi Res. Another can of worms IMHO and totally unneeded today.

Why unneeded? If you have an old CD that is HDCD and a DAC that can decode it would you not want to use it that way and see the light come on. I think I would. 

[vortecjr]

29 minutes ago, Axiom05 said:

I was really referring to the need for new recordings using HDCD. Honestly, I was hoping to replace all of my Reference Recordings HDCD CD's with Hi Res files and dispense with the need for HDCD decoding completely. Unfortunately, RR has only made a relatively small number of their recordings available in Hi Res while many remain only available as HDCD encoded 16-bit. Also note that some CD's from other labels that claim to be HDCD encoded really are not encoded, they are just plain CD's that were recorded using a PM2 ADC. There  really are only a very small number of true HDCD encoded recordings out there. I would venture a guess that many of these recordings, which could be 20+ years old now, have been replaced with newer recordings and are no longer played. I did not buy a QX-5 Twenty for its HDCD capability and certainly could happily live w/o the ability to decode HDCD files.

Sounds like you are still affected by all of this;) The software I ran some time ago to find the HDCDs found more in my library than I though I had. 

[vortecjr]

30 minutes ago, Norton said:

 

XXHE decodes HDCD.

Good one.

[vortecjr]

29 minutes ago, pkane2001 said:

 

I ripped and converted  all my HDCDs to 24bit decoded files using DBPowerAmp. Had about 20 of them, as it turns out.

Part of my problem is I don't remember what I did with mine:) 

[vortecjr]

39 minutes ago, pkane2001 said:

 

I ripped and converted  all my HDCDs to 24bit decoded files using DBPowerAmp. Had about 20 of them, as it turns out.

DBPowerAmp appears to use HDCD software as it's decoder. 

[vortecjr]

4 hours ago, manisandher said:

 

If the labels used a PM1/2, they certainly had the ability to encode HDCD fully. But whether they did or not would be down to whether they invoked any of the various HDCD encoding processes in the PM1/2.

 

When I had my PM2, I could create fully encoded 16/44.1 HDCD files. I chose not to, because I preferred the sound with no HDCD encoding at all - perhaps other labels shared my preference?

 

Actually, I created very few encoded/non-encoded 16/44.1 files - I much preferred the sound of 24/176.4 or 24/192, where the PM2 starts sounding really magical.

 

Mani.

Preferences aside if you look at the data online the 16/44.1 version is compromised unless you decode it.

 

I scanned my library with FooBar2000 and found 64 albums with the embedded HDCD flags. According to the output from FooBar2000 some of these have their min gain set to 0 DB, max gain set to 0 DB, peak extension disabled, and transient filters disabled. Seems pointless to convert and compare these.  

[vortecjr]

14 hours ago, manisandher said:

Actually, I created very few encoded/non-encoded 16/44.1 files - I much preferred the sound of 24/176.4 or 24/192, where the PM2 starts sounding really magical.

 

Mani.

Mani, are you able to provide me an encoded file made with your former PM2 and the original unencoded file? 

[vortecjr]

20 hours ago, tmtomh said:

The Pacific Micrsonics units allow for a number of HDCD features to be turned on or off during production. Some are "transient filters" aka a primitive version of MQA's claimed filtering, whereby the HDCD music file tells the HDCD-capable playback device what filter to apply based on how the file was encoded during production.

IMHO this is a useless feature. The only really useful/audible feature is Peak Extend, as noted above in this thread.

 

Not a whole lot of HDCDs are encoded with Peak Extend. The big notable ones are much of the Grateful Dead and Neil Young catalogues. If you don't have those, then you're likely to have a very small number of Peak Extend-enabled HDCD discs in your collection.

 

An HDCD can be ripped and then post-processed (also as noted earlier in the thread) to decode the HDCD content. The decoded HDCD stream is actually only 20-bit, but since that's an oddball bit-depth, the processing software always pads it out with 4 bits' worth of zeros, to produce a 24-bit file that can be played back pretty much any DAC.

 

All of this illustrates why HDCD is not very compelling technology. All that hassle for just 4 extra bits of bit-depth doesn't seem worth it - especially since exactly zero HDCDs with Peak Extend have musical content whose dynamic range exceeds the 96dB range of normal 16-bit CD. So what Peak Extend really did was enable engineers to peak-limit the mastering, because HDCD allowed the limited peaks to be recovered. If they just mastered the content at the proper volume to begin with, they wouldn't have needed to limit the peaks in the first place.

I actually have a lot of HDCDs that have the Peak Extend feature enabled. This thread is not really about if it's worth it or not. The fact is that the content exists and needs to be dealt with properly in a collection.   

[vortecjr]

14 hours ago, CatManDo said:

I recently ripped my entire CD collection. There were some HDCDs among them, some with peak extension, some without.

 

I found this ripping procedure (using EAC and CUE Tools) on the Steve Hoffman forum and it worked well.

 

 

https://forums.stevehoffman.tv/threads/ripping-hdcd-sacd.301966/#post-8265734

 

Maybe there are quicker procedures, but for my collection (about a dozen HDCDs among 3000 CDs) it was fast enough. I haven't yet done a comparison between the non-HDCD rip and the 24/44 rip.

I used Foobar2000 to scan the library and list the albums with the Peak Extend feature enabled. I then used DBPowerAMP to decode the files. 

[vortecjr]

10 hours ago, manisandher said:

 

Will have a look Jesus, but not sure if I'll be able to find any - it was a while ago now, and I gave up on 16/44.1 pretty quickly from what I can recall. Leave it with me...

 

Mani.

Thanks.

[vortecjr]

15 minutes ago, tmtomh said:

 

Well, how worthwhile it is on balance, given the overall number of HDCDs with Peak Extend on the market, is on-topic for a thread whose title includes the phrase "HDCD feedback."

 

But putting that aside for a moment, my comment clarified the bit-depth of the decoded HDCD stream, and that is substantive information. 

Again, that is not the purpose of this discussion. However many there are on the market they exist and I'm looking for comments...do you like them or not and under what circumstances. 

 

I didn't take exception to your comments on the technical aspects. 

[vortecjr]

8 hours ago, tmtomh said:

 

Your first post asked, "what is your experience with it?" My comment was responsive to that. If you really want to keep going back and forth about what's on-topic, we can do that, but it seems beside the point. I certainly agree an HDCD thread is useful, and I'm glad you started one.

I'm trying to keep this thread from becoming a MQA type tread. People are free to post their feedback on it and experience without making an argument for or against it. The intent here is to discuss if people like them or not and discuss possible reasons why or not. Also, some people don't even know they have them and the goals is to show people how to identify them and use them properly so we get feedback that matters.    

[vortecjr]

Moving on...I noticed something interesting from the Foobar2000 scan of my library. The scan did not identify any hi-resolution content with the HDCD markers. I would have thought that the Reference Recording HRx tracks would be identified. According to the Reference Recording website, "Currently we record at 176.4 kHz/ 24 bits, with HDCD, and that is what we put on our HRx discs." 

 

https://referencerecordings.com/format/hrx

 

So this brings up some concern. The research I have done suggests that the HDCD recordings on CD are distorted unless you play them back via a hardware or software decoder. So naturally, I have to wonder if the HRx HDCD recordings on DVD are also distorted unless you play them back via a hardware or software decoder. More research is needed to know if the software decoder even works on the Reference Recording HRx tracks. 

[vortecjr]

6 hours ago, tmtomh said:

 

This sounds very strange (not criticizing you; rather, referring to the Reference Recordings web site blurb). HDCD was designed for 16-bit recordings and I'm not aware of any existing decoder chips that look for HDCD data except in the 16th bit. In other words, even if Pacific Microsonics makes/made an ADC capable of applying HDCD encoding to a 24-bit data stream and burying the HDCD data in the 24th-bit, I don't think any consumer playback device could decode that.

 

The way the Reference Recordings blurb is written, it is not clear what they mean when they say they still currently use HDCD in the production of their high-res recordings. If they do, I would guess that probably means they use Pacific Microsonics ADC units - which happen to be HDCD capable - to digitize their recordings. But I would be very surprised if they enable the substantive features of it - Peak Extend and Low-level Range Extend. It would hardly be necessary with high-res content, since high-res provides more bits and more dynamic range than HDCD (24 bits vs 20 bits), and again, AFAIK no consumer playback software or hardware could decode those features if they were embedded in the least significant bit of a 24-bit stream.

 

In other words, one can use a Pacific Microsonics ADC for recording, and enable HDCD but not actually use any HDCD features - which means the resulting disc/file will trip an HDCD flag but there's no actual HDCD data or features in the digital content. In fact, I believe one can even use a PM ADC and simply turn off its HDCD features altogether, meaning one can record non-HDCD content using a PM unit. In that case, one might still say "we use HDCD" when they really just mean "we use PM equipment to digitize our recordings." I suspect one of these two scenarios is what happens with Reference Recordings' high-res material.

 

So that leaves the digital filters - both the filters used in the ADC during recording, and the digital filters built in to any HDCD-certified/capable hardware playback device. Part of HDCD's claim was that the digital filters built in to HDCD hardware players were special/high-precision/very good. And presumably they were considered to match up well, or be complementary, to the filtering used by the Pacific Microsonics ADC.

 

Software HDCD decoders/players do not, AFAIK, necessarily have such filters - or if they have multiple filters choices, I don't know that they automatically switch to HDCD filters when playing back files that were ripped from HDCD discs.

 

Finally, as to your concern about HDCD recordings on CDs being "distorted" unless played back on HDCD hardware or software, there are two sources of distortion:

1. Increased noise, because the HDCD data is buried in the 16th bit, meaning it's in the dither, and because HDCD data is by definition not random, it therefore makes the dither not totally randomized - and since the entire function of dither is to reduce the perception of quantization noise by randomizing it, HDCD encoding makes dither less effective. Again, this is not an issue with high-res content (because it hardly matters if it has a 23-bit effective noise floor vs 24), but theoretically an undecoded HDCD will have only a 15-bit noise floor, while a decoded HDCD will have a 20-bit noise floor. This is not distortion per se, but it does reduce S/N ratio.
2. Distortion of peaks if Peak Extend was used. Peak Extend is a reversible soft limiter - basically just like the widespread digital limiters used (and overused) in mastering today, except HDCD Peak Extend saves the original peak info and it can be restored during playback by an HDCD-capable device or software. So playing an HDCD with Peak Extend on a non-HDCD playback device will result in the peaks being limited. That's unfortunate, but it's not going to result in audible distortion in most cases, because the peaks are soft limited rather than hard-clipped: the peaks will be altered and their dynamics reduced, but the entire point of soft limiting is that it avoids audible distortion (unless the mastering engineer pushes the levels so hard and abuses the limiter so much that it can't round off the peaks properly).

Someone knows a lot about HDCD:) 

[vortecjr]

5 hours ago, manisandher said:

 

If you use a PM1/2 to play back the HRx 24/176.4 files from RR, the HDCD LED will illuminate. However, don't be fooled by this - there are no HDCD processes beyond 16/44.1. So you can play back the HRx files on any DAC with no more added distortion than there would be playing them back on a PM1/2.

 

(I used to have a DAC with a PMD200 filter, which also illuminated the HDCD LED when playing back HRx files. But DACs with this filter (as opposed to the regular PMD100) are few and far between.)

 

Mani.

My Oppo is suppose to decode HDCD, but it will not via network playback. I can't even try it here with a cd because the disks are stored elsewhere.

 

I contacted Reference Recording and they emailed me saying, "Built into the program for HDCD is a filter morphing ability, which seamlessly looks ahead in the music to handle changes in timbre or transients. That is always on and in use if the HDCD flag is on.  

 

I also contacted Jim Web who wrote the articles in the technical section I added to the top post. Jim was kind enough to look at a sample HRx file for me. On quick look he didn't find the usual flagging, but is looking into it more.

[vortecjr]

4 hours ago, Miska said:

 

No, as far as I know there's no free implementation available as source code, nor public specifications. It goes into exactly same category as MQA...

 

What about source code from ffmpeg? 

[vortecjr]

5 hours ago, Miska said:

 

I have successfully ripped all my few (3 Mark Knopfler albums in total) HDCD encoded CDs into 24-bit AIFF using dbPoweramp and the HDCD decoder plugin. The plugin's gain setting just works exactly opposite way than what at least I understand from the description. So check the results afterwards in Audacity for correctness, that you don't get extra clipping! I needed to do the ripping twice because of this.

 

I get the same results..I think. The bottom one is the ripped track. I did not select the checkbox to avoid any clipping.  

 

[vortecjr]

2 hours ago, Miska said:

In my opinion, HDCD is best dealt with at ripping time, decoding as necessary and thus get rid of the problem at once for good. It may require bit of extra hassle at that point, but then it is done...

 

I agree based on your circumstance because you have two albums. My collection was ripped many years ago and I recently found almost 1000 tracks with the embedded HDCD flags. I located them, moved them into a work folder, converted them with the DBPowerAMP converter, and then moved them back into my library, but what a pain that was to do. Also, I only converted the titles that had peak extension enabled and this takes a little more time to sort out.  

[vortecjr]

Here is an interesting update for HDCD decoding with DLNA streams.

 

I emailed Simon N with MinimServer and explained the current state of affairs and included some links for him to read. Simon was very receptive to the idea as adding HDCD decoding and now has it working in his lab. In an upcoming release he will add HDCD decoding via ffmpeg to MinimServer/MinimStreamer.   

[vortecjr]

5 minutes ago, Miska said:

 

Do they have something for that too? It doesn't mean it is usable in a commercial product though. It is massive amount of work to clean up ffmpeg such way that it can be used in a commercial product... It could be that would have to go too...

They sure do. HDCD is both nowhere and everywhere if you look for it:) I didn't look at the code...

https://ffmpeg.org/ffmpeg-filters.html#hdcd