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Old 1st July 2011, 06:52 AM   #1961
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Klaus,

you can use the DSP effect ReplayGain or ReplayGain Apply with the dBPoweramp batch converter.

Uli
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Old 1st July 2011, 07:54 AM   #1962
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Quote:
Originally Posted by uli.brueggemann View Post
Klaus,

you can use the DSP effect ReplayGain or ReplayGain Apply with the dBPoweramp batch converter.

Uli
Hi Uli.

Yes I know. I can also use Foobar. I'd like to use Linux though.

What I do is following:

1. Apply replay gain according to 89db reference (-14db relative to full scale)
with metaflac
2. Apply a system specific correction value to the album gain tag with
puddletag
3. Squeezbox Server adds that value to the actual volume setting prior
to processing.

The plan is to handle 1.+2. with puddletag in the future.

I can highly recommend puddletag as tag tool. It's just the best I came across.


Cheers
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Old 1st July 2011, 09:41 AM   #1963
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Hi guys.

In OSX land there are apps (Pure Audio - The OSX Reference Player and Audirvana) which offer a so called integer mode.

The stock OSX was and still is feeding the DAC drivers with floats.

These rather new audiophile minded apps avoid that float/integer conversion now on driver lever. They feed integers to the driver.
The driver needs to accept integers of course.

People claim that this is effect is audible.


Does anybody know how it's done in Linux land?

Cheers

Last edited by soundcheck; 1st July 2011 at 09:45 AM.
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Old 1st July 2011, 11:42 AM   #1964
phofman is offline phofman  Czech Republic
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Third, Pure Music 1.8 now includes nonmixable integer stream format support, bypassing all floating point operations on certain DACs.
Which card supported by alsa accepts float samples? I do not know of any, apart of perhaps X-fi. Maybe there are closed-source drivers in OSX where the card/driver manufacturer chose to use both int and float samples for communication between the userspace and driver and Pure Music goes for the int format only now. Unfortunately we cannot check the source code and have to rely on often vague description by the author.

I do not see this feature anyhow relevant to alsa.

Last edited by phofman; 1st July 2011 at 11:44 AM.
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Old 1st July 2011, 12:06 PM   #1965
phofman is offline phofman  Czech Republic
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Or maybe I understand the wording differently and the author means the player does not do any floating point operations. Though I have no idea why for certain DACs only.

In any case bit-perfect chain in alsa does no FP operations. The sample rate converters do, as well as perhaps the softvol plugin.

For up to 24 bits the conversion between int and float is bit perfect as the mantisa of float32 has 24 bits.

Why should several int instructions on CPU sound better than a single float instruction on the same CPU?
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Old 1st July 2011, 12:37 PM   #1966
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Quote:
Originally Posted by phofman View Post
Or maybe I understand the wording differently and the author means the player does not do any floating point operations. Though I have no idea why for certain DACs only.

In any case bit-perfect chain in alsa does no FP operations. The sample rate converters do, as well as perhaps the softvol plugin.

For up to 24 bits the conversion between int and float is bit perfect as the mantisa of float32 has 24 bits.

Why should several int instructions on CPU sound better than a single float instruction on the same CPU?
No, as far as I understood it is about feeding the driver with integers instead of floats. Not all drivers were supporting it , since OSX requires floats.


Todays 32 bit DACs do push the limits. Float/integer conversions do need to be discussed in this context I guess.


The reason behind all that is to avoid extra processing further downstream.
They now follow pretty much the same philosopy that I'm running since years.



Cheers
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Old 1st July 2011, 02:01 PM   #1967
phofman is offline phofman  Czech Republic
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Originally Posted by soundcheck View Post
No, as far as I understood it is about feeding the driver with integers instead of floats. Not all drivers were supporting it , since OSX requires floats.
OK, I do not know what part of OSX specifically requires floats. Alsa drivers almost exclusively expect integers.

Quote:
Originally Posted by soundcheck View Post
Todays 32 bit DACs do push the limits. Float/integer conversions do need to be discussed in this context I guess.
Well, they accept 32bit samples as it is a cheaper and more universal format to handle. Effectively they do not exceed 19-20bit S/N as it is down to physical properties of chips. Since internally they are one-bit DACs anyways, it is just about the digital control circuits. No advantage for their analog performance over 24bit-only DACs.


Quote:
Originally Posted by soundcheck View Post
The reason behind all that is to avoid extra processing further downstream.
IMO the driver should accept only the sample formats the hardware actually supports. Conversion from any intermediate or source formats is job of user space layers. Standardizing on float32 would be unexpected. But who knows how it actually works in OS-X. I don't :-)
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Old 4th July 2011, 01:30 PM   #1968
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Hi there.


A sidenote to the float integer conversion discussion.

You might find int-float-int-its-jungle-out-there.html
interesting.

It seems that it is not that easy to say if an application or library
delivers bit transparent data if it messes around with the float/integer
conversion.
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Old 4th July 2011, 04:31 PM   #1969
RR is offline RR  Europe
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Quote:
Originally Posted by soundcheck View Post
Hi folks.

I just applied replaygain tags to some files.


I used metaflac which unfortunatly supports =< 48khz SR only.

I'm wondering if anybody of you know if there's a tool ( commandline preferably ) supporting sample rates > 48khz?
Hello,

Try libebur128. http://www-public.tu-bs.de:8080/~y00...ibebur128.html

It implements the EBU R-128 loudness recommendations. Foobar2000 has switched to R-128 recently.

The r128-scanner command included in the packet can tag directories recursively. No problems with 96/24 in my tests also.

Cheers,

Roberto
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Old 5th July 2011, 06:36 AM   #1970
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Quote:
Originally Posted by RR View Post
Hello,

Try libebur128. http://www-public.tu-bs.de:8080/~y00...ibebur128.html

It implements the EBU R-128 loudness recommendations. Foobar2000 has switched to R-128 recently.

The r128-scanner command included in the packet can tag directories recursively. No problems with 96/24 in my tests also.

Cheers,

Roberto
Great stuff Roberto. Thx a lot. That seems to be exactly what I was looking for.

I didn't know about those EBU R-128 recommendations, since I never considered using replay-gain for a long time.

Just recently I figured that the Squeezebox-server just adds the gain to the normal volume settings.
I tried it and was very happy with the result. I do consider it extremely annyoing to adjust the volume for each
and every album.

I found a nice article about those EBU recommendasions. An interesting read I think.

I hope that one day the mastering studios comply to such a standard.


And a big "thank you" to the folks fighting the Loudness-War and not giving up on it for quite some time.


Cheers

Last edited by soundcheck; 5th July 2011 at 06:38 AM.
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