Subject: Re: [linux-audio-dev] LADSPA Specs ?
From: Paul Davis (pbd_AT_op.net)
Date: Sun May 12 2002 - 00:54:09 EEST
>you mentioned that you have never seen any plugin that outputs a
>different number of samples than inputs. I think the time-stretching
>plugin is a very legitimate example, and I certainly don't understand
>your rationale that a time-stretching plugin should output the same
>number of samples under the same frequency sample rate. You see, my dear
>friend, this wouldn't be time-stretching.
I'm afraid it would. You need to think about this some more. In any
given unit of time, a certain number of samples are transformed into a
varying air pressure wave. What matters is the relation between those
samples and the original source material. The number of them remains
the same per unit of time whether the signal is altered or not.
However, what you may be thinking of is a different (though clearly
related) problem. Many "time stretching" algorithms (the ones that do
not operate independently on pitch and duration) cannot be used in
real-time, because if the speed is supposed to increase, they run out
of samples to process.
This is why LADSPA has flags to indicate that a plugin is not suitable for
real-time (i.e. streaming) use.
--p
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