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Capture devices enumeration fails, but device still works RRS feed

  • Question

  • In my application I let the user select a number of video sources to be used (i.e. analyzed in realtime).
    Everything worked fine with two different Logitech webcams and a DV camcorder.

    Then I wanted to add a third Logitech webcam - all the three cameras are of different models.
    Well, since then the enumeration of the video sources fails in my code but also in GeaphEdt and in AmCap...
    What happens is that only one of the many connected devices is enumerated - i.e. shown in the list.

    The funny thing (well, funny...) is that in the device manager every source is recognized correctly as an imaging device...
    But what puzzles me is the following:
    - I removed all the webcams
    - re-plugged webcamA. The system recognizes it, my app, graphedt and amcap work ok with it.
    - I save the capture graph into "capture.grf" file
    - Then I plug webcamB too. The system recognizes it.
    - In all the apps I can see only webcamB now. But webcamAs mic is available!
    - I load "capture.grf" into graphedt... and it works correctly with webcamA!!!

    I seems the problem is only in enumerating the capture devices...

    Anyone can suggest a solution - apart from formatting and reinstallin, I mean?

    Thanks for your attention.
    Friday, September 21, 2007 1:29 PM

Answers

  • The Logitech camera's don't like working with other Logitech cameras at the same time.  I've had similar problems as well as random BSOD during usage if multiple Logitech camera's are used in parallel.

     

    Monday, September 24, 2007 4:14 PM

All replies

  • The Logitech camera's don't like working with other Logitech cameras at the same time.  I've had similar problems as well as random BSOD during usage if multiple Logitech camera's are used in parallel.

     

    Monday, September 24, 2007 4:14 PM
  • It was ok until I installed the third webcam driver... Well: I found I can still work with two Logitech cameras. I have to plug the first, create its graph, plug the second camera (first one at this point doesn't show in available capture sources) and build its graph... and the application works well with both the webcams...
    ...whatever...

    bye
    Friday, September 28, 2007 8:27 AM
  • Another rule to check is separate usb headers.
    Another thing is, everytime a cam is pluged into a different header for the first time, the device is usually recognized as 'new' and needs the driver files associated with it before working.
    Some software does not handle either 'device lost' or 'new device', and only enumerates upon initial execution.

    Sounds like you have a few debugging variables to stroke out to know for sure. It is also adviseable to get a usb/fire wire pci card. Seriously, with more than two webcams.
    Saturday, September 29, 2007 4:18 AM
  •  Bowljoman wrote:
    Another rule to check is separate usb headers.

    Sorry, I'm not sure I understand. By "header" do you mean a phisical USB plug?
     Bowljoman wrote:
    Another thing is, everytime a cam is pluged into a different header for the first time, the device is usually recognized as 'new' and needs the driver files associated with it before working.
    Some software does not handle either 'device lost' or 'new device', and only enumerates upon initial execution.

    This is the case of Graphedt - as far as I know - but my app shows all the DShow-aware capture devices present in the system, even if plugged after the app's launch. It worked well before I installed the third webcam driver.
    In fact, it still works... For instance: I start the app, then plug webcam#1, I ask to add a new capturegraph, the one and only webcam#1 appears in the available capture devices. I select it and the app works fine. Then I plug webcam#2, "ding-dong" from thre speakers, then I ask to add a new capturegraph. While webcam#1's graph still works ok, only webcam#2 appears in the selectable capture devices. I select it, and now the app works ok with both the cameras.
    I know - well, I suppose! °____° - what you are about to say: the first camera doesn't show in the list because it's already working and in fact it is not available... but this is not true: if I try to add a third source, the list appears to show still only webcam#2, and let me select it - only that this will generate an error (and this is the behaviuour I wanted...).
     Bowljoman wrote:

    Sounds like you have a few debugging variables to stroke out to know for sure. It is also adviseable to get a usb/fire wire pci card. Seriously, with more than two webcams.

    I'm developing the application on a notebook, this is the reason why I used webcams, but the target machine will use Euresys Picolo framegrabbers. Apart the near future, I'd like my app to run as smooth as possible with all the DShow compatible capture devices.
    Monday, October 1, 2007 8:24 AM