Post by onlymee January 23, 2007 (1 of 10)
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Hello all. I am working with a company developing a whole new way of DSP that replaces FFT. We can already upsample audio to a pretty impressive level and are moving to the PS3 as a development platform. Anybody know how I can get hold of info such as address maps etc so that I can tinker with the A-D and DACs ??
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Post by Peter January 23, 2007 (2 of 10)
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What are DSP, FFT?
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Post by Karlosak January 23, 2007 (3 of 10)
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DSP = Digital signal processing
FFT = Fast Fourier transform
onlymee, I'm not sure you'll find such an expert here who could help you, though I may be wrong?
Can you shed some light on this project, it sounds interesting...
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Post by Peter January 23, 2007 (4 of 10)
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Thanks. DSP I now understand. The other I'll pass on for the moment!
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Post by tommwi January 23, 2007 (5 of 10)
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Peter said:
What are DSP, FFT?
Don’t you know THAT?
This is essential knowledge for all SACD listeners… :)
DSP is probably Digital Sound Processing. I have it in one of my Audio Video Receivers. It tries to fool me to believe I’m listening to a famous concert hall acoustic in Amsterdam – in my own living room (!). Unfortunately it has some similarities with those here who argue for the superiority of 5 channels SACD. But that’s just a personal thought since I lack understanding of what 5 channel really is all about… (dont kill me now!)
FFT is for me a function in a program (SW) called MATLAB. It carries out something called Fourier transformation I have a university degree in this but I think I will leave out the explanation of it to the math teacher who visit this site quite often :) It is quite remarkable though, since it can bring some help to identify the many frequency components in a complex sound picture. It is probably there to enable some DSP actions or should I say manipulation of the frequency response…
Well-there most be hundreds of other meanings too. And better explanations…
/Tommy
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Post by Peter January 23, 2007 (6 of 10)
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tommwi said:
Don’t you know THAT?
This is essential knowledge for all SACD listeners… :)
Tommy, I'm too old and too stupid, even though I'm the other Maths teacher on the forum.....who only taught sums. :-)
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Post by eesau January 23, 2007 (7 of 10)
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onlymee said:
Hello all. I am working with a company developing a whole new way of DSP that replaces FFT. We can already upsample audio to a pretty impressive level and are moving to the PS3 as a development platform. Anybody know how I can get hold of info such as address maps etc so that I can tinker with the A-D and DACs ??
Hi,
this information can only be acquired from Sony (or you need to do serious reverse engineering yourself ... or start up a group that does that ... ask about this in some hacker forum because I believe it may already exist).
Note, that PS3 is an open platform only when it comes to developing games. I believe the audio interface is standardized as some PS3 specific API and the HW under it is not available for developers.
PS3 is a VERY complex processing system with multiple processors and it may be very tedious to program even with Sonys existing programming tools. But it can be very interesting, too.
Good luck.
Esa
PS. I think that PS3 as SACD player is 100% proprietary and Sony will not allow any hacking of it because they want SACD security to be unbreakable forever.
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FFT is indeed a Fast Fourier Transform, which is (merely!) an efficient implementation of a Fourier Transform; itself a generalisation of a Fourier Series. This makes it possible to encode and decode vast amounts of sound information in real time.
A Fourier Series is essentially a way of using simple trigonometric functions (cosine and sine) - albeit in very complex combinations - as a way to represent any curve (including straight edged ones).
For those who wish to discover more about the wonderful universe of maths and Fourier Transforms in particular, have a look here: http://mathworld.wolfram.com/FourierTransform.html
As Tommy indicated, apart from mathematicians or physicists (mathematicians in denial!) and those engineers designing audio equipment (grubby mathematicians?!?) I'm not quite sure that this is required knowledge for SACD listeners. When I was studying, this topic got dangerously close to being directly useful so I dropped it very quickly!
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eesau said:
PS. I think that PS3 as SACD player is 100% proprietary and Sony will not allow any hacking of it because they want SACD security to be unbreakable forever.
For security issues like PSP (Pit Signal Processing) that'll certainly be true but for DSD decoding and D/A conversion I doubt that (although they *will* want to make sure that the DSD signal doesn't go anywhere else than a secure output i.e. HDMI).
In the meantime, here's some interesting coverage: http://www.beyond3d.com/forum/showthread.php?t=36188
There's some discussion on the SA-CD.net forum (look for threads from the November/December 2006 timeframe) as well as on others concerning the question whether PS3 outputs DSD on HDMI. It appears not (instead the DSD signal gets converted to hi-res PCM and there seems to be no menu setting to alter this) but I've got no firm answer to this yet and I don't have my own unit yet.
For highly detailed developer information about the Cell processor look here: http://cell.scei.co.jp/e_download.html
There's an in-depth presentation here: http://www.research.scea.com/research/html/CellGDC05/index.html
I'm not quite sure however you'll find anything on FFT here. Good luck and keep us posted :)
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Post by onlymee January 24, 2007 (10 of 10)
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eesau said:
Hi,
this information can only be acquired from Sony (or you need to do serious reverse engineering yourself ... or start up a group that does that ... ask about this in some hacker forum because I believe it may already exist).
Note, that PS3 is an open platform only when it comes to developing games. I believe the audio interface is standardized as some PS3 specific API and the HW under it is not available for developers.
PS3 is a VERY complex processing system with multiple processors and it may be very tedious to program even with Sonys existing programming tools. But it can be very interesting, too.
Good luck.
Esa
PS. I think that PS3 as SACD player is 100% proprietary and Sony will not allow any hacking of it because they want SACD security to be unbreakable forever.
Thanks for all the repsonse! Yep I have all the IBM Cell stuff ready to go. We wrote our code with a special instruction set that allows parallel processing (we had to do it in assembler), and it is a natural for the Cell Arcitecture. FFT is the universal method for processing but it is lossy. Our method os loss-less and if you are into DSP, well that opens up a whole new ball game. As far as audio goes we can up sample with total faithfullness to the original, indeed we have done.
Looks like we will be tearin the thing apart, but it seems the hardware I want is not there - an SPE ( its part of the Cell MPU) takes care of the audio and the DACS sem to be inside a dedicated I/O DSP.
Anyway, thanks all for so much interest.
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