SACD decoder options Options

[Anakunda]

Hello,

perhaps somebody can explain meaning of SACD decoder options.

ASIO Driver mode: PCM / DSD (Autodetect) difference
and
DSD2PCM mode: Multistage (fixed point) / Multistage (floating point) / Direct (Floating point, 30kHz LF) difference

I'm utterly aimed to get highest quality for converter..

What's the native sampling frequency for SACD? I have 4 choices which 44.1 is too low, but there are higher. I intuiitionally choosed 88.2kHz but not sure if this still isnot downsampling the undecoded audio. I need a value that won't up/downsample the audio any way and extracts in the same reate as original. Thankyou.

[NiPP0]

2822.4/24=117.6... 117.6KHz isn't a rate so we have to do 2822.4/32=88.2. I don't think the plug-in outputs 32-bit, so it would have to be converted to 24-bit. This would keep about 75% (24/32) of the DSD's audio data. Going to 96/24 wouldn't be a good idea, so 176.4/24 would be the next step up. This would be overkill by about 50% (2822.4/176.4=24, 24/16=1.5).

I'm sure DSD -> PCM conversion algorithms will keep being improved, so while I planned on doing 176.4/24 FLAC I'm thinking it would be better to do 88.2/24 and keep the .DFF/.DSD/SACD .ISO. Remember that even at 352.8/24 conversion can't be considered lossless.

When editing an image (lossless or not) I prefer to down-sample the final output slightly rather than up-sample it. This is based on the fact the original image may have slightly less than optimum spatial resolution, so downsampling gives me the feeling that the ouput is 'honest' (contains as much data as it should).

Any ideas on the dithering question?

NiPP0

This post has been edited by NiPP0: Apr 7 2012, 22:16

[SoNic67]

2822.4/24=117.6...

That's why I said that 88.2kHz is not quite there.
Actually the definition of DSD is 1-bit with 64 times the CD samplerate (CD is PCM at 16 bit depth). So if you want precise calculation, you have 28822.4/16=176.4kHz@16 bit.
It makes no sense to divide to 32 bit since there are no real DAC's that can take advantage of that PCM bitdepth. Sabre, Texas Instruments and Wolfson have each one 32 bit DAC cip in production, but the datasheet performances are not better than previous 24 bit DAC cips. Actually, the higest quality are some "24 bit" DAC's. Even those reference DAC chips don't attain more than 20-21 bit of real resolution (the lowest 3-4 bit are just electrical noise). To make things worse, the best performance of the same top-of-the-line DAC cips happens at 96kHz (not at 192kHz). THD+N specs tell the story.
So, keeping the resulting PCM at 24 bit 88.2kHz is IMO the best solution.

This post has been edited by SoNic67: Apr 8 2012, 00:42

[lvqcl]

Actually the definition of DSD is 1-bit with 64 times the CD samplerate

Agree.

So if you want precise calculation, you have 28822.4/16=176.4kHz@16 bit.

And this is absolutely meaningless.