If it was never encoded with PE, the overall level would have to be reduced slightly, causing a slight reduction in the available bit depth.
My point exactly. So all in all they're just adding more headroom (i.e. possible dynamic range) to an audio format that already has waaaay more dynamic range capabilities than anyone uses.
Maybe this will help clarify: (1) You are correct that HDCD peak extension will not increase dynamic range over the original master. (2) You also are correct that compressing the original master and encoding it to HDCD with peak extension is silly - why not just avoid compression in the first place and then you don't have to encode it at all? (3) However (and as testikoff just posted above while I was typing this), the "loudness wars" resulted in a lot of recordings being compressed during mastering so their average volume level would be louder. HDCD peak extension encoding enables this compression to be reversed when played back on HDCD compatible equipment. (4) In addition, HDCD decoding results in a digital file/stream that uses 20 bits of resolution, as opposed to CD's standard 16 bits. You are certainly correct that 16 bits already allows for more than sufficient dynamic range - but regardless, the "higher-resolution" (really higher bit-depth) capability of HDCD-encoded discs was touted as a sonic benefit. So the bottom line is, I think you actually do get it - but like many of us, you seem to feel HDCD was a solution to an unnecessary or nonexistent problem.
Again, I'm naive to this concept, but it seems to me that the bit depth is not changing in this scenario. Instead, the compression is squishing more dBfs into a set number of bit Thank you for clarifying. This indeed is what I assumed
Lightbulb moment!! So the existence of this technology allows mastering engineers to have their cake & eat it too...to give customers a fully dynamic master (for those who own a decoder) while also having a compressed "louder" master to size up to other masters when play listed for radio, etc.? If this assumption is correct, then the existence of it seems more valid to me Iguess...
Ditto! Too bad, a lot of HDCD releases did not utilize Peak Extend feature while crushing the dynamics, i.e. Van Halen, Roxy Music, Bryan Ferry, etc. HDCDs.
As above, it's a way (with PE and LLRE) to squeeze 20 bits worth of dynamic range into 16 bits, via a "sliding window". If you had a 20 bit master that was quite dynamic, converting to 16 bit would require one of the following: - limiting or clipping the peaks, and bringing the overall level up - keeping the level as-is, but truncating or dithering the least significant bits HDCD encoding/decoding (with PE and LLRE) basically adjusts the volume during peaks and very quiet sections so neither of the above is necessary. Upon encoding it reduces the level of peaks and increases the level of quiet content as to fit them into a 16 bit space, and then does the reverse upon decoding to allow for 20 bits of dynamic range overall. That's more or less a side effect.
Yes - theoretically, HDCD peak extension encoding a digital solution to the analogue-realm problem of having to "ride the gain" while recording in order to preserve the loudest passages while avoiding having the quietest ones get lost in noise. The only goofy part is, as others have noted above, it's hard to imagine a recording (except maybe a handful of classical ones) that would need this in the digital realm, given the 96dB (120dB perceived using good dither) S/N ratio of 16-bit digital. A small irony is that, AFAIK, HDCD encoding takes up two bits, so the non-encoded signal on an HDCD-encoded CD isn't 16 bits, but rather only 14 bits.
Irony is that these 2 Bits can be considered as random noise on every CD. HDCD encoding takes advantage of that and decodes extra info into the least significant bits. Even if it isn't used (by a non HDCD Encoder) it doens't degrade audio quality because of "nicer aligned" noise In fact, you can come up with a decoder, that decodes secret messages into your 16Bit PCM audio Question is, whether enabled peak extension harms listening through a non HDCD Encoder or not... because peak extension does alter the most significant bits of an audio signal (which could result in clipping).
Does anyone know if Joni Mitchell/'Court And Spark' has peak extension? Apologies if this has been answered prior!!
All Joni's albums on HDCD that I own utilize Peak Extend feature(& sometimes Gain, too). I, however, don't have Court And Spark HDCD in my collection...
HDCD.exe detects no HDCD encoding features enabled for The Ragpicker's Dream or Get Lucky. Sailing to Philadelphia has peak extension. Those are the only solo Mark Knopfler CDs I have. (same results with foobar2000. Both methods detect peak extend, low level gain/extend, and transient filters even though neither will "decode" transient filters.)
Like I said, MK's HDCD-encoded solo albums, i.e. Local Hero (OST), Cal (OST), The Princess Bride (OST), Last Exit To Brooklyn (OST), Golden Heart, Wag The Dog (OST), Metroland (OST), Sailing To Philadelphia all feature Peak Extend (not Shangri-La HDCD).
I'm sorry; I parsed that as "Mark Knopfler -- all solo albums are HDCD encoded except for Shangri-La". My mistake.
I thought there was nothing to decode when it came to that particular feature of the HDCD process. Isn't it just an indication of whether or not the mastering engineer set the encoder to use those filters when converting the master to HDCD? I mean, they could also have chosen to indicate whether the engineer had blue eyes, or enjoyed strawberry ice cream. Would have been equally relevant information as far as the playback chain is concerned!
I think there's a theory that it could trigger different filters upon playback when using HDCD DACs, but of course that would only be the case when using HDCD compatible DACs for D/A conversion; if you're sending the decoded 24 bit output to another DAC, any sort off filter switching wouldn't happen. If it happens at all.
I am curious about this. Theoretically, because I don`t believe this has ever been demonstrated to actually happen in practice, what benefits would be conveyed by selectively applying filters to material on the decoding side (material that has already been filtered during the encoding phase, mind you) when converting HDCD signal back to analogue? What would be left to filter, exactly...?
No idea. I've never looked into it that closely, and I'm not sure how one would even test it. But I've seen posts where people believe it could be implemented in playback. On the other hand, this claims it is definitely only during encoding: http://www.head-fi.org/t/65414/hdcd-list/510#post_7202096
The compander bit (Peak Extension and Low-Level Extension), that I understand. I use companders all the time, particularly in wireless signal management for stage audio production applications. The switchable dither is also a great tool for encoding to 16-bit, and no one is denying the PM converter sounds terrific with or without HDCD features engaged. But I am interested to know who on earth thinks that having different anti-aliasing filters is in any way relevant to decoding. Is your playback device going to start oversampling at a different frequency if it detects a certain anti-aliasing signature? Why would that make any difference? It should not, in fact it probably does not matter. Any amount of oversampling is `good enough` to capture the original signal on the decoding side, from what I understand of these things. Maybe they were trying to promote some proprietary non-oversampling analogue lowpass filter on HDCD-decoding CD players. Ew. Personally, I am sticking with my conventional playback chain and converting all my Peak Extend-enabled HDCD material to full-range 20-bit signal, upsampled to 24-bit at 96kHz. That way it most certainly does NOT matter what filter was used in encoding.
KMFDM-Symbols 1997 KMFDM-Megalomaniac 1998 Soundtrack-City of Angels 1998 Tracks 1-10 have Peak Extension, no HDCD on the rest
Thanks! Picked this up at a Goodwill a little while back. Didn't realize most of the tracks are HDCD.
