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HDCD rescue - it's possible, but man...

I spent the better part of today sick, but working on finding a way to decode music I might have that is HDCD encoded.

As a refresher, HDCD was an enhanced CD format. In some ways the predecessor to MQA. HDCD was an engineer's toolbox, allowing the mastering engineer to select a number of features. This would then be decoded by a matching chip on a CD player or DAC. The most famous feature of HDCD was bit-compression. Getting a 24 bit signal encoded in a 16 bit music file.

As an aside, the Pacifics Microsonics AD converters were highly prized by engineers for their sound quality. Anyway, the format got bought by Microsoft and died.

Of the 670 CD's I have ripped only about 11 were HDCD encoded. But man, what a pain. I ripped everything to FLAC, but the HDCD decoder only does WAV. I had to download source, compile it, then write a script to go through every CD and decide if it's HDCD or not. Once found, I have to convert from FLAC (44/16) to WAV, decode the WAV file (now 24 bits) and convert back to FLAC to compress again.

The discovery process was pretty fast.  About 10 minutes to go through them all by cheating. :) More time was spent figuring out how to pass apostrophe's in file names than finding the files.  Nathalie Merchant was one author who consistently used HDCD by the way.
erik_squires
erik_squires OP
16,119 posts
 
All the evidence I see so far points to:

- PM gear in mastering process turns HDCD flag on.
- Engineers don't use any features
- CD's get mastered with HDCD "data tag" but no features used.
- Label gets printed without HDCD because it's not real.
- Some one on the internet starts making list of all HDCD disks, whether real or just tagged.
georgehifi's avatar
georgehifi
10,312 posts
 
- CD's get mastered with HDCD "data tag" but no features used.
- Label gets printed without HDCD because it's not real.
PB Nightclub, hdcd sounds far better than non hdcd, same session.
Don't know what I'm getting at here.
Cheers George
erik_squires OP
16,119 posts
 
It’s quite possible some real HDCD disks also never did the labelling. :)

I could check my recordings, I suppose, but meh, it’s all automated.

That Patricia Barber CD with the HDCD label really IS HDCD though. :)

Sorry I think there’s some misunderstanding, let me be as verbose as I am not sober. :)

So, HDCD has a special data tag that digitally marks a CD track as being HDCD enabled BUT, that tag could get added unintentionally, without the engineers actually using any of the HDCD features, in which case it’s no different musically than plain old redbook.

HDCD requires manual intervention during the mastering, there's no "set and forget" about it.
erik_squires OP
16,119 posts
 
There is a software solution, ffmpeg, that should be able to tell you whether a track is redbook, HDCD tagged but not used, and real HDCD. It's not that useful unless you want to conserve disk space though. :) I mean, it's kind of academic.

Best,


E
ptss
1,964 posts
 
Erik,your link doesn't work. For me a smaller space relates only to choice of smaller loudspeakers. You?
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