6dB boost on DSD->PCM

[paulster]

Poiko

Referring to this thread: viewtopic.php?p=33298&hilit=6db#p33298

There are apparently a number of SACDs in the marketplace that violate the scarlet book standard for DSD encoding, and exceed -6dB, so that if you do a straight PCM conversion and boost the levels by 6dB you will experience clipping (the US original SACD pressing of Thriller is one such example). Is it possible to add clipping detection and/or a feature to reduce the boost or disable it if required for the specific source material? I would imagine now that labels are generating DSD files for download distribution rather than cutting on physical discs they may also start to play looser with the official standards, so the assumption that peak levels will not exceed -6dB may turn out to be a bad one.

Thanks.

[paulster]

Some more information in this thread, and another request there to make this configurable: viewtopic.php?p=32800&hilit=dsd#p32800

At least if you had the option to run the DSD/PCM conversions at 0dB you'd be able to look at the resultant replaygain track loudness output to see if -6dB was ever exceeded, and could then re-encode at the higher level if the source files adhered to the Scarlet Book standard.

I'm finding that the SACDs I'm ripping all peak at 0dB when converted to PCM, so I don't know whether the original mastering pushed them right to the -6dB limit, and this has now been bumped up to 0dB cleanly, or whether they've now been clipped.

[poiko]

I made the Option (on DSD to PCM conversion gain):

Untitled-1.png (17.94 KiB) Viewed 177 times

Download:
https://download.poikosoft.com/ez_cd_au ... l_test.exe

[thexfile]

.

[paulster]

This is awesome! Just testing it now, and the first two discs I tried ended up with peaks at -4.33dB and -5.45dB when choosing the 0dB gain level, so those would have clipped previously. Going through some other SACDs now.

Not that it's important, but does this option change the corresponding gain reduction for going from PCM to DSD, or does that remain fixed at -6dB and this controls only the DSD to PCM conversion?

[poiko]

This is awesome! Just testing it now, and the first two discs I tried ended up with peaks at -4.33dB and -5.45dB when choosing the 0dB gain level, so those would have clipped previously. Going through some other SACDs now.

Not that it's important, but does this option change the corresponding gain reduction for going from PCM to DSD, or does that remain fixed at -6dB and this controls only the DSD to PCM conversion?

Only adjusts the DSD to PCM decoder gain

PCM to DSD encoder is always -6 dB per standard

[paulster]

So I'm 3 for 3 in terms of SACDs that exceed the Scarlet Book standard of -6dB, with the latest one I've tried coming in at -3.73dB.

This is definitely a worthwhile feature upgrade then, for anyone that's doing DSD to PCM conversions.

[paulster]

Checked another SACD today, and that one peaked at -3.56dB, so that's 4 out of 4 discs so far that have exceeded the Scarlet Book standard of -6dB peak.

I would recommend, based on this sample, that the default be 0dB for DSD to PCM because, unless you're going to scan the disc in advance of ripping, there is a high likelihood that the standard +6dB gain will result in clipped PCM files.

[paulster]

Current count is 8 out of 9 discs exceeding -6dB, so it's abundantly clear that the Scarlet Book standard was only ever treated as a guideline.

Having this ability to properly set the conversion gain now is a big deal, as it means this functionality is now really usable in real world scenarios.