Re: [Jack-Devel] Mixing inside process callback

On Wed, Mar 06, 2013 at 07:36:30PM +0100, Slavko Glamočanin wrote:
> This is a basic sound design question and i feel you will have many more on
> the path you have chosen:)
> 
> Jack doesn't care if you produce abnormal values and strange things start
> to happen if you do.
> 
> Quite basically, when writing values to the jack buffer, if the value is
> below -1, set it to 1, if it's above 1 set it to 1.
> 
> Everything else should be up to the user, set the default mixing volume
> around 0.8.
> 
> You could also create a limiting curve to map actual values to limited
> values and so emulate a limiter.

This would render JACK unusable for professional audio. If values above
1 or below -1 occur inside a floating point DAW like Ardour it doesn't
matter much. It's up to the user to ensure that values are attenuated
before they reach the DAC. It would be unacceptable for JACK to mess around
with this stuff in the background.

Is there anything preventing you from using a lookahead limiter if values
over 0dBFS are a concern in your own work situation?

John

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