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Old 13th April 2010, 08:19 AM   #1561
phofman is offline phofman  Czech Republic
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Quote:
Originally Posted by soundcheck View Post
Hi folks.

Is anybody aware of a little command line tool which converts volume in 64bit double precision and adjusts in db stepping?
Under windows you'll find more and more tools which run DSP work in 64bit throughout the entire DSP chain.

Sox is afaik 32bit.
Ecasound is 32bit.
brutefir is 64bit - at least the filters are doubles - but I guess the VC too?

I'd just need a simple offline tool which is able to handle .wav in 16/44.1 for testing.

THX
Adjusting volume is a single one division operation producing only one rounding error. There is no error cummulation calling for high-precision DSP. 32bit division operation for 16 bit input/output numbers has already 15 extra useless bits (the MSB of the cut-off can be used to decide the LSB of the 16bit output result - standard rounding).
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Old 13th April 2010, 08:25 AM   #1562
phofman is offline phofman  Czech Republic
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Originally Posted by Onvinyl View Post
I case you are talking to me, I disagree. I choose gentoo on purpose, although it needs more learning, the returns are wealthy, because the available online information sources are comprehensive.
Of course the chosen distribution will have no effect on the resultant bit stream entering the sound card, provided everything in the chain is correct and setup in comparable manner.

Quote:
Originally Posted by Onvinyl View Post
Btw, is there a simply wav-editor that doesn't need X-windows out there? I need it to cut ends and beginnings of captured analog sources.
Rüdiger
Check out sox SoX - Sound eXchange | HomePage , you will find it does all you need and much more
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Old 13th April 2010, 09:02 AM   #1563
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Quote:
Originally Posted by phofman View Post
Of course the chosen distribution will have no effect on the resultant bit stream entering the sound card, provided everything in the chain is correct and setup in comparable manner.
Yes, I agree. My point is, that with gentoo it is easier to assure the correctness of the chain, once one is atop of the learning curve...

Thanks for the tip with SoX, it seems to provide everything I need when capturing from my soundcards ADC.

Rüdiger
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Old 14th April 2010, 06:48 AM   #1564
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Originally Posted by Onvinyl View Post
Yes, I agree. My point is, that with gentoo it is easier to assure the correctness of the chain, once one is atop of the learning curve...
What kind of logic is that?

You might climb up the learning curve - which is a very bumpy, steep and long curve to climb.

The biggest challenge though will be to stay on top of it - if you ever manage to get there - to the top.
After a while you'll spent more time on the Linux then on your audio to maintain your position. Been there, done that. ( my ZEN-Kernel adventure with the Gentoo folks)

If a misconfigured mpd.conf almost breaks your neck - I consider that curve even bumpier and longer. Though it is your choice. Fair enough.

BTW - what was your problem with the mpd.conf. Would be nice to share your solution with us. Getting that kind of feedback is quite helpful for people supporting you ( to stay on top of it ).

Cheers
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Old 14th April 2010, 06:55 AM   #1565
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Quote:
Originally Posted by phofman View Post
Adjusting volume is a single one division operation producing only one rounding error. There is no error cummulation calling for high-precision DSP. 32bit division operation for 16 bit input/output numbers has already 15 extra useless bits (the MSB of the cut-off can be used to decide the LSB of the 16bit output result - standard rounding).
Appreciate that lecture, even though it doesn't answer my question . (If I would have listened to you all the time I'd still be living in (audio-)caves or on (audio-)trees )

Just to get back to my question. Do you know a tool? ( Under Windows I could name several)

Cheers
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Old 14th April 2010, 07:22 AM   #1566
phofman is offline phofman  Czech Republic
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(If I would have listened to you all the time I'd still be living in (audio-)caves or on (audio-)trees )
Whereas now you are living in self-built dreams very apart from reality.

Quote:
Originally Posted by soundcheck View Post
Just to get back to my question. Do you know a tool? ( Under Windows I could name several)
Since it is a mathematical nonsense, I am not surprised developers are not wasting their time. Windows world is full of hard-core audiophiles who need their daily portion of voodoo to keep themselves happy. And if there is demand there is supply.

Tweaking sox source code is trivial - just override the 32bit int with 64bit long int on both sides of the lines where the division occurs. Though I would not be surprised if the compiler optimized-out this extra code since it is a redundant nonsense.
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Old 14th April 2010, 08:15 AM   #1567
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phofman.

They're running floats.

In vol.c and it says:

Code:
typedef struct {
  double    gain; /* amplitude gain. */
  sox_bool  uselimiter;
  double    limiterthreshhold;
  double    limitergain;
  int       limited; /* number of limited values to report. */
  int       totalprocessed;
} priv_t;
Though, if I recall it correctly vol is being depreciated.

and also in gain.c

every calculation has a "double" in front of it.

I am not that fast as you in grasping what's going in there ( I am not a programmer). Still I believe by looking inside gain.c, I understood they do all processing in double precision already. Which makes sense. You wouldn't
switch precision in a DSP chain. If it is overkill or not.

Would be nice if you could confirm that. ( Edit: Even though if it would slightly weakening your earlier taken position about Voodoo-Windows designers) )

Cheers

Last edited by soundcheck; 14th April 2010 at 08:22 AM.
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Old 14th April 2010, 09:08 AM   #1568
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Klaus,
your attitude is perceived as being arrogant at this end of the line.

With gentoo, I was able to solve my issues, probably because of the in-depth information I found on the web (and did not find for ubuntu).

Gentoo's supported rt-kernel (not the ZEN-kernel) is well documented (though not so easy to find) and compiling your own custom kernel is easy just because of this. No more issues with wrong or suboptimum autoloaded modules, for instance.

The problems with mpd and brutefir was, as is so often, a mixture of several problems. First, mpd wasn't compiled with pipe enabled (I could have sworn I did ), then I had typos in mpd.conf ('brutefir -nodefaults /root/brutefir_config' instead of 'brutefir -nodefault /root/.brutefir_config'), last issue was that brutefir is called with mpd's user permissions so brutefir couldn't read its own config file.
Of course, all this silly problems were ... silly, but solvable.

Rüdiger
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Old 14th April 2010, 10:54 AM   #1569
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Originally Posted by Onvinyl View Post
your attitude is perceived as being arrogant at this end of the line.
Perception of arrogance always depends on your personal and emotional view and situation. Just shoot back with facts, that's the best cure for that kind of feeling.

phofman and me are playing games all the time. Either of us could consider the other one being "ignorant" - but arrogant - no that's not it. I just like the challenge behind it. I consider these kind of discussions pretty constructive, since IMO there is usually a certain truth in what's being said from both sides.

Back to your case. It should be allowed to make some comments about "choosing Gentoo because of the correctness of chain". Which still doesn't make any sense to me.
By telling us what was wrong with your mpd.setup - you pretty much confirm what I was referring to. You're on a steep learning curve in Linux-Hacker land.
And your issues had nothing to do with Gentoo, Ubuntu or whatever distro.

Does this sound arrogant?

Cheers
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Old 14th April 2010, 10:58 AM   #1570
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Does this sound arrogant?

Cheers
Quite so.
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