RE: Jaguar Audio changes
RE: Jaguar Audio changes
- Subject: RE: Jaguar Audio changes
- From: "Tracy Lakin" <email@hidden>
- Date: Mon, 20 May 2002 13:17:28 -0700
- Thread-topic: non real time bouncing and music events
Re: Jaguar Audio changes
I've found that Jaguar is not stable enough for development.
My Wallstreet Powerbook was killed dead by installing Jaguar. The Power Manager was somehow affected, and the machine is "crowbarred" and will not even give me a boot chime. This is apparently the hardware/firmware saying that there is not enough power to boot up, even when plugged in or with a fresh battery. Disconnecting the PMU cable does not fix (a standard fix attempt). I've ordered a new motherboard battery in the hopes that this will fix...
Now, a caveat -- other developers, and the Core OS folks at Apple I talked to at the WWDC, have Wallstreet PB's and they did not experience this. But I was running OS X 10.1.4 just fine onthe PB, and this did not happen until I installed Jaguar at the WWDC, just to get the new Audio code (I'm writing an Audio Unit).
Also, our G4 desktop machine (year old) went into a hang state with Jaguar. After booting up, about twenty seconds later the Finder puts up the wait cursor and never recovers. I've gone back to 10.1.4. The DAVE Audio Unit example app still runs, having built it under Jaguar, but it crashes a lot (I think it crashed a lot anyway, so hard to tell if this is a 10.1.4 compatibility issue).
I propose that you make available, perhaps as a software seed, the new Jaguar Audio frameworks, for use under 10.1.4 or 10.1.5. In talking to you folks at the WWDC, it appears that this is feasible. That is, there are no dependencies on other Jaguar code.
If you really want us to suffer on with Jaguar, then I ask: are you guys (Apple Core Audio team) running Jaguar? If so, are you using the same installer and installation we were given at the WWDC?
Anyone else out there have better luck with Jaguar? Should I just reinstall again? I've lost so much time so far, I'm not very encouraged. I spent two days in the DTS lab trying to recover my PB at the WWDC instead of going to sessions. (Big thanks go to those folks, especially George Warner.) But I want the new Audio code.
Thanks,
Tracy
>
-----Original Message-----
>
From: Bill Stewart [mailto:email@hidden]
>
Sent: Saturday, May 18, 2002 12:53 PM
>
To: Jean-Alexis Montignies; CoreAudio API
>
Subject: Re: non real time bouncing and music events
>
>
>
BTW - a couple of things I forgot to mention
>
>
The Generic Output will do the format conversions for you, so:
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(1) Make sure you set the output property of the bus of the
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output unit
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you're going to be pulling on - this can be in the format
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that you want the
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data to for writing to the file
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(BTW - You have the new AudioFile APIs in Jaguar - so you
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should be able to
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use them to write the file out).
>
>
Bill
>
>
on 18/5/02 12:46 PM, Bill Stewart wrote:
>
>
> Yes you can
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>
>
> Basically you have to start the sequence as you would normally.
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>
>
> The difference is in how you interact with the graph...
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>
>
> You'll need an output unit that is a generic based one (not
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a device based
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> one) - this is a new audio unit (Generic Output) that is
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available in Jaguar
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> (and there is a new set of classes already for this in the
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AudioUnit SDK if
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> you want to make your own)
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>
>
> When you start the sequence (MusicPlayerStart), this will
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turn around and
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> start the graph, which will turn around and start your output unit.
>
>
>
> OK - so you should install a property listener on the
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generic output (which
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> you've added to the graph of course - a gotcha! - if you
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had been using this
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> graph with a device output unit, then you'll have to remove
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the device output
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> unit first - then add the generic output and connect it up
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- an AUGraph can
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> only have one output unit at a time)
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>
>
> OK - so the property you listen for is the isRunning notification.
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>
>
> That will fire when you start the graph.
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>
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> Then, in your notification you now know that the graph is
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ready to go. The
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> generic output unit however, does nothing, so you have to
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do the work. But its
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> simple...
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>
>
> You call the generic output unit's RenderSlice call -
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supplying a buffer of
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> data that you will get filled by the graph. You're also
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responsible of course,
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> for mainting the validity of the time stamps - in this case
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the only valid
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> field of the time stamp I would guess is the sample count
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(though you could
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> supply a host time stamp as well, but as you're rendering
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in an offline
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> situation, you probably don't want to do that).
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>
>
> Each time your render slice returns you now should have a
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buffer of rendered
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> audio - which you could then write out to disk. Then pull
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on it again
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> (incrementing your sample count), until you have the data you need.
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>
>
> Then when you're done, you call stop on the sequence
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(MusicPlayerStop) -
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> you'll get the notification that you've been stopped, but
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of course you
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> already know that!
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>
>
> That should be it.
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>
>
> This sounds like a good piece of sample code to write - so
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I'll endeavour to
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> do that before we're finished with Jaguar (good way to test
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that this all
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> works as we expect it to!)
>
>
>
> Bill
>
>
>
> on 18/5/02 11:21 AM, Jean-Alexis Montignies wrote:
>
>
>
>> I imagine it's possible to use a audio graph for
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processing audio to
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>> save it to disk by pulling samples as fast as the graph
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can process them.
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>>
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>> The question is :
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>> How can you feed a synth unit when you're not in real time?
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>>
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>> I don't see how to use a MusicSequence.
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>>
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>> Would it be possible to use an audio unit to pull music
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events? (The
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>> role of the unit would be to send music event when asked to fill a
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>> buffer)
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>>
>
>> Jean-Alexis Montignies
>
>> Sen:te
>
>> _______________________________________________
>
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>
>
>
>
> mailto:email@hidden
>
> tel: +1 408 974 4056
>
>
>
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______________________________________________________________
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____________
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mailto:email@hidden
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tel: +1 408 974 4056
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______________________________________________________________
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____________
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"Thousands of years ago, cats were worshipped as gods. We have never
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forgotten this."
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______________________________________________________________
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