Re: more AU info and plugins (should be "I need to share data")
Re: more AU info and plugins (should be "I need to share data")
- Subject: Re: more AU info and plugins (should be "I need to share data")
- From: Bill Stewart <email@hidden>
- Date: Sat, 21 Jun 2003 14:43:33 -0700
On Saturday, June 21, 2003, at 02:13 PM, Andrew Kimpton wrote:
I'm coming to this thread a little late (and perhaps my
point/question) is what started this all, but consider the following
three pieces of UI information that are all pretty common in an Audio
Effect or processing plugin.
VU Meter,
Waveform display (Amplitude over time)
Frequency display
In these cases the data under examination is changing very rapidly (in
the DSP part of the plugin), it might be changing as rapidly as the
buffer rate, but even if we 'slow' the rate to that of the screen
(what's the point of displaying more frequently than screen updates ?)
The rate of the data is still 60-85Hz
The quantity of data is also large in the last two cases, probably a
'buffer' or 'array' of between 256 & 512 32bit floating point values
(ie 1-2KBytes of Data), there are probably other examples of realtime
display with even more data.
These are simple bounded examples, is the decision (feeling) that
they are too large and of too high a rate to be handled through
Get/Set Property ? If so the UI implementor has no choice (these
displays are must have's in many processing plugins) but to 'reach
over the wall' and obtain or maintain some other reference, pointer or
communications channel with the DSP Component.
No they aren't.. QuickTime uses the component API for ALL of its video
codecs and there are MANY MANY component dispatch calls for every frame
of video that it draws...
This argument is a complete red herring.
Bill
If such behaviour is felt likely to break apps in the future, or even
break them now then someone (Apple) should set some strong guidelines
and provide alternatives or workarounds where appropriate. Or make it
clear to the app vendors that they should do nothing in their
applications to break the above mechanisms of access.
I've not (yet) seen AudioUnits performing this sort of visual feedback
(though I've not looked as hard as I might across the list of units on
OSXAudio.com) perhaps the lack of guidelines is why - it certainly
gives me pause before rushing to implement a plugin with such UI
features.
Andrew 8-)
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