[SOLVED] How to extract tracks from SACD ISO

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admin
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[SOLVED] How to extract tracks from SACD ISO

Post by admin » Fri Aug 03, 2018 5:21 pm


daham95
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Re: How to extract tracks from SACD ISO

Post by daham95 » Sun Jun 09, 2019 3:44 pm

Hi,
I am currently evaluating xrecode especially with respect to SACD audio extraction.
My aim is to extract native DSD/DFF content without conversion (to eg. WAV or flac).

This works as described in this threat/how to, however, for all the tests I've made so far, all extracted DFF files will clip when being converted afterwards.
So is it a real native extraction of the files as authored on the SACD or is some attenuation applied (or rather neglected)?

AFAIK SACD mastering usually should include +6dB headroom. So when extracting to DFF I would expect for most files to find up to +6dB of headroom.
However all my extracted DFF filles come out at 0dbfs with clipping/ Intersample peaks.

I haven't found any additonal setting I could activate for extraction.
I only found it for the conversion setting (which I primarily do NOT intend) where a selction between +0dB and +6dB could be made.

Best regards
Daniel

admin
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Re: How to extract tracks from SACD ISO

Post by admin » Sun Jun 09, 2019 4:36 pm

Hi,

SACDs are extracted as-is and no conversion is performed on the extracted data. DSD encoding is 6dB quieter than PCM, that's why there's a SACD setting to raise the level by that number, when converting from DSD to PCM.
all extracted DFF files will clip when being converted afterwards.
How exactly did you do this?

daham95
Posts: 4
Joined: Sun Jun 09, 2019 3:23 pm

Re: How to extract tracks from SACD ISO

Post by daham95 » Sun Jun 09, 2019 5:26 pm

Hi,
the extracted DFF files I put into a Sample Rate Converter (in this case XiSRC from Xivero).
The intput DFF was shown as 352.8 khz 24bit and I converted it to 88.2/24 WAV, just for experimenting
In XiSRC I did not the flag for ISP reduction setting (which is available).

However, I also tried some other sacd.iso files in between, where the underlying mastering of the source file probably was better than my initial SACDs I used for testing.
So here I got DFF files which did not show any clipping and did still have some headroom (although not +6db).
admin wrote:
Sun Jun 09, 2019 4:36 pm
... DSD encoding is 6dB quieter than PCM, that's why there's a SACD setting to raise the level by that number, when converting from DSD to PCM.
That's why I sent this reply. I would have expected all DFF extractions to at least show +6db of headroom (depending on the original mastering of the source track). But apparently this does not seem to be the case.
Songs that are (re-)mastered around 0dBFS before SACD authoring is applied (assuming to be done correctly with +6db headroom) also seem to be extracted around 0dBFS and might clip after conversion to PCM.

Daniel

daham95
Posts: 4
Joined: Sun Jun 09, 2019 3:23 pm

Re: How to extract tracks from SACD ISO

Post by daham95 » Sun Jun 09, 2019 6:29 pm

Hi again,

after having done some more tests I assume that the +6db for SACD headroom is JUST a setting or flag that is applied during SACD authoring BUT is completely independent from the audio source files that are being authored for SACD playback.

If the source files for SACD authoring are "hot" mastered, ie. having peaks around 0dBFS (and beyond because of Intersample Peaks) then also a extracted DFF file will look exactly the same.

My assupmption is that SACD extraction will extract the source file "as is" without knowing about any (headroom) settings being applied during authoring which might instruct subsequent playback devices how to behave during playback.

So I assume that with the headroom flag being set during authoring, eg. SACD players when reading the SACD and also the set flag, just output the authored file 6db lower than it actually has originally been mastered.
Otherwise I could not explain why some of the extracted DFF files seem not have any headroom at all (because originally they weren't mastered that way).

Best regards
Daniel

daham95
Posts: 4
Joined: Sun Jun 09, 2019 3:23 pm

Re: How to extract tracks from SACD ISO

Post by daham95 » Mon Jun 10, 2019 1:15 pm

Hello,

my last assumption probably doesn't hold true. A +6db "flag" in SACD authoring does not exist.
So this means, if my DFF > PCM converted files clip this is because of the (badly) SACD mastered files.
However, then these files weren't properly mastered according to the underlying SACD "Scarlet Book" Standard according to relevant "Annex D3".

I found a good explanation in a "SACD Production Guide" for the Pyramix DAW.
https://www.merging.com/uploads/assets/ ... 0Guide.pdf

The chapter for "Merging & Levels" says:
...
"Reference Level
All DSD peak-meters are aligned to "0 dB SACD". The SACD reference level ("0dB SACD") is defined as -6dB FS PCM. Final DSD Edited Masters can have levels as high as +3.1dB SACD, a.k.a -2.9dB FS PCM for very short durations. In practice, for safety, we recommend a general rule of not going over 0 dB SACD. Levels higher than this value will be clipped if using the same master for doing the CD layer of the SACD master and might also have an adverse effect on SACD playing time. Even worse, such a master may be rejected by SACD manufacturing facilities." ...

So some of my extracted DFF > PCM converted files that clipped definitely must have been mastered at "+3.1db SACD" or even higher.
Other examples I extraced were mastered correctly: DFF extraction > PCM conversion: showed +1.3db headroom. The same file, eg. when extracted from the SACD.iso file using a PCM conversion with simple decimation and choosing +0db gain resulted in a wav file with +7.3db headoom.

As you said before:
admin wrote:
Sun Jun 09, 2019 4:36 pm
SACDs are extracted as-is and no conversion is performed on the extracted data. DSD encoding is 6dB quieter than PCM, that's why there's a SACD setting to raise the level by that number, when converting from DSD to PCM.
Xrecode does exactly what it should do. It's the mastering engineers that in these cases apparently didn't stick to the SACD level standards when the SACD was authored.

Daniel

admin
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[SOLVED] Re: How to extract tracks from SACD ISO

Post by admin » Tue Jun 11, 2019 6:01 pm

Yes, it seems that not all SACDs follow the 6 dB rule, at least that's what I found when googling around for more info.

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