On Mon, 22 Nov 2004, Garth Cummings wrote:
>
> Hi Zach,
>
> On Nov 20, 2004, at 11:49 PM, zach wisor wrote:
>
> > I was wondering if anyone could help me, or point me
> > in the right direction to developing a driver and or
> > program to allow my Sony Handycam (DCR-HC20) to
> > connect to my iMac via USB. The handycam itself
> > supports "Usb streaming" in windows, however, sony
> > didn't deem it worthwhile to make the same
> > capabilities for macintosh. So any help or tips would
> > be greatly appreciated.
>
> I haven't seen one of these cameras, so I don't know whether the "USB
> Streaming" feature is done via a vendor-specific protocol or a public
> spec like the USB Video Class. You can tell by looking at the camera in
> USB Prober. But you need the protocol spec either way. If it's
> vendor-specific, you would first need to get the protocol spec for the
> "USB Streaming" feature from Sony.
>
> Without the spec, you're into serious hack mode and we can't help you
> there.
Something which _can_ help you if you have access to a Windows PC is
software like usbsnoop/SnoopyPro (found e.g. on sourceforge).
It's a USB sniffer. It logs everything that goes on over USB (you can
select just one device/interface to monitor). You just install it on the
PC, then connect the camera and go through the operations you'd like to do
on your Mac, noting down what appears in the log for each operation. By
operations I mean things like rewind, stop, play, or whatever else the
Windows software can do.
Don't bother capturing a whole lot of actual streaming, it's the setup and
teardown that you're interested in - plus the log from streaming will
include all the streamed data and thus be very big :)
Then go and analyse the logs to find out how the protocol works. Usually a
pattern will emerge without too much head-scratching ... but of course,
sometimes people just like to make things complicated for the sake of it.
Make sure you read up on how USB works at low levels first 'tho or else
the log won't make much sense.
I've used this tool to make Mac drivers for a USB device that lacked them,
and it really isn't too bad at all. (Much much easier than a PCI device).
> --gc
> __________________________________________________________________
> Garth Cummings
> Apple Developer Technical Support email@hidden
>
> http://developer.apple.com/technicalsupport
{P^/
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