Identifying a USB camera

Phil Davis revdev at pdslabs.net
Thu Apr 24 14:28:42 CDT 2008


Hi Richard,

Digital camera access from within Rev can get pretty confusing - one 
camera works and another doesn't. When a camera presents itself to the 
OS under the USB mass storage device class, Rev can see it as a mounted 
volume. But when the camera presents itself under the USB still image 
capture device class and uses Picture Transfer Protocol (PTP) or some 
derivative to move images to your computer, Rev can't see it, at least 
not natively. That's my best guess anyway.

Sounds like an opportunity to write a Rev PTP library!  ;o)  If you do, 
I'll gladly show it off in my "Working with USB" session at RunRevLive.

Some references:

USB mass storage device class:
http://en.wikipedia.org/wiki/USB_MSC

USB still image capture device class and PTP (Picture Transfer Protocol):
http://en.wikipedia.org/wiki/Picture_Transfer_Protocol


Hope this helps -
Phil Davis


Richard Miller wrote:
> Perhaps what I'm trying to do is impossible, or has to be done some 
> other way entirely.
>
> MY COMPUTER (under XP) identifies the camera as "canon powershot 
> a410". If I double-click it, it opens to a window full of jpeg's (as 
> I'd expect it to). But going into Rev and doing the following produces 
> only "can't open directory" errors:
>
> set the defaultfolder to ""canon powershot a410"; put the files
>
> It doesn't matter if I put a colon after A410 or a colon and a slash. 
> I just get errors.
>
> The problem may also be that all the photos on this camera are on its 
> SD card. Perhaps there's no way to get to them directly through Rev?
>
> Thanks.
> Richard
>
>
>
> On Apr 24, 2008, at 2:30 PM, Richard Miller wrote:
>
>> How can I access a camera through Rev? I plugged in a Canon Powershot 
>> camera (USB). It shows up in My Computer with its name, but no volume 
>> number. THE VOLUMES function in Rev doesn't see it. I suppose I could 
>> use the Registry, but I'm hoping for some other approach. I need to 
>> be able to identify any camera plugged in via USB without knowing the 
>> model in advance.
>>
>> Thanks.
>> Richard Miller_______________________________________________
>> use-revolution mailing list
>> use-revolution at lists.runrev.com
>> Please visit this url to subscribe, unsubscribe and manage your 
>> subscription preferences:
>> http://lists.runrev.com/mailman/listinfo/use-revolution
>
> _______________________________________________
> use-revolution mailing list
> use-revolution at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your 
> subscription preferences:
> http://lists.runrev.com/mailman/listinfo/use-revolution
>

-- 
Phil Davis

PDS Labs
Professional Software Development
http://pdslabs.net




More information about the use-livecode mailing list