Re: HAL Devices and Streams (with QuickTime)
Re: HAL Devices and Streams (with QuickTime)
- Subject: Re: HAL Devices and Streams (with QuickTime)
- From: <email@hidden>
- Date: Mon, 21 Jan 2002 01:33:13 -0600
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> Jeff Moore wrote:
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> 2) the HAL sdev does have an Get/SetInfo selector to change what
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> AudioDeviceID it is using. It is, unsurprisingly, siHALAudioDeviceID.
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>
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> But, and this goes back to what I was trying to get at when I talked about
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> the Sound Manager's architecture getting in the way, the Sound Manager will
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> use the same sdev for all the tracks in a QTMovie without being pointed at a
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> wholly different sdev Component using MediaSetSoundOutputComponent.
Above you say "the Sound Manager will use the same sdev all the tracks in a
QTMovie"... I don't need a track by track control, only movie by movie.
(Two movies playing at the same time on different outputs). Does this
change anything? Is there another function that will work?
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> If you know exactly how many output devices your app will need, for
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> instance 2, (like for my app: main output & monitor) a quick & dirty
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> solution would be to install 2 Components in the OS which are exact copies
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> of the HAL Output Component except for their id (componentSubType,
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> componentManufacturer), right? this way, the Soundmanager would look at
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> them as 2 different Components (not just 2 different instances of the
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> same Component), and you would be able to use both...
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>
This would work, as long as the device didn't go away while you were using
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it.
That's fine by me... Can they both be used at the same time?
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> but I guess there's
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> no way of copying the HAL Output Component, is there?
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You could make an sdev that delegated all it's calls to an instance of the
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HAL sdev in it's dispatcher.
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This kind of construct should cover you 90% of the time. The places where
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you'll be tripped up is the boundary conditions, like the device going away.
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It's much easier to make this work for your specific application than it is
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to make it work on a general basis.
OK, this is sounding doable. Whew! I'll be sure to add a warning message
about disconnecting devices. Now it's time to hack...
Thanks Lieven for your help finding the workaround! Hopefully with time
QuickTime (and/or the Sound Manager) will be updated to fix the problem.
-Jason