Looking at darwin? (was: Re: BSD video capture emulation question)

Doug White dwhite at gumbysoft.com
Tue Jul 15 22:45:58 PDT 2003

On Tue, 15 Jul 2003, John-Mark Gurney wrote:

> > This description does sound pretty much like what I've seen discussed here,
> > except that the discussion here has focussed specifically on Video drivers,
> > not "all" IO devices (and note that not necessarily all devices have (or
> > need) userland access)
> Too many people are thinking physical instead of logical.  We already
> have the physical side of things, the driver talking to the hardware to
> control it.  What we don't have is the logical glue to glue the parts of
> the driver together into one easy piece.  This is what the code I would
> like to see do.

That stuff is in QuickTime, which Apple cannot and will not ever release
code to, as good chunks of it are licensed from third parties, and its the
crown jewels :)

QT takes care of repackaging the device driver outputs and inputs into
APIs that programs hook.  Your average Mac webcam app just looks at the
list of available QuickTime video capture devices; it doesn't care if its
USB or FireWire or whatnot.  The audio system does the same thing; this
way all audio capture devices look the same, even if its the onboard sound
or USB, or a program masquerading as an input device.

On the other hand, the QuickTime APIs are published.  You could use those
as a starting point.

Doug White                    |  FreeBSD: The Power to Serve
dwhite at gumbysoft.com          |  www.FreeBSD.org

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