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  1. #1
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    Qt Imaging/Camera APIs and competition - feedback requested

    The PureView Imaging Competition 2012Q2 is nearly half way through and we've had some cracking entries!

    Given the quality of entries, I'm sure that some of you will have some useful feedback about our camera and imaging APIs - what works, what's missing, what is "harder than it needs to be". If anything they'd like to share, please post it here, or email me. If you didn't compete but feel you have something useful to add, I'd love to hear that too!

    This is not a waste of time! The feedback provided from competitions is sent into Nokia R&D and informs the next generation of our design. For example, we've already fed back comments about the lack of access to camera setting information in the QML Camera Element - a problem that is being addressed in Qt 5.0

    ----

    In addition, this competition is being run quite differently than previously:
    * We're spreading out prize awarding into segments
    * Prizes include trip as well as (awesome) phones
    * The entries we'll accept are very "broad"
    * I'm subediting articles when I can to help improve them across the judging period.
    * Judging is using a wider pool of champion and moderator members

    I'd appreciate your feedback on what you like and dislike about this approach.
    * Are the prizes cool enough? What would tempt you to compete?
    * What aspect of the competition did you like least
    * Is there a competition topic you'd like to see?
    * What sort of competitions do you like - app contests or wiki contributions

    Thanks very much!

  2. #2
    daliusd
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    Re: Qt Imaging/Camera APIs and competition - feedback requested

    I'm not sure if I'm not saying complete non-sense but that might be interesting idea for PureView technology. I guess using public software API it is not possible but using internal API or at hardware level it should be possible to take pictures at slightly different times using different points. E.g.: we separate our matrix into 4 separate pictures and take each picture at times t, t+d, t+d*2 and d+d*3, where d*4 = 1/fps (spf - second per frame). This way it would be possible to make slow motion videos at 120 or even 240 fps (not full hd but still quite impressive).

  3. #3
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    Re: Qt Imaging/Camera APIs and competition - feedback requested

    A couple of things:

    I guess the biggest problem might not be the APIs themselves, but their implementation on products. I'm only talking about the still image camera APIs here.
    For example, N9 Qt API seems to offer only auto & point focus modes, but not macro, infinity etc... And N8 seems to lack auto white balance (of all things...).
    Of course, capture to buffer should have other formats than a heavily compressed JPEG -- which is completely undocumented.
    Especially now that bigger sensors are coming, tempting for creative camera implementations, manual focus and manual shutter speed should be available.
    Support for EXIF info in captured images is obvious.

    For some reason, the standard camera apps in N9 and N9 seem to have a much shorter shutter lag than is possible with the Qt APIs -- or there is a trick to it.

    Yet, the Qt Mobility APIs are a fantastic improvement compared to the previous approaches. Thank you for that!

  4. #4
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    Re: Qt Imaging/Camera APIs and competition - feedback requested

    A couple of things:

    The first thing i kind had a hard time with was fetching the camera frames for processing.
    It took me a while before i had "Custom Camera Hello World" example up and running.
    IMHO, i feel that there should be a straightforward example on the docs page for this. The ones that are already there
    have too much stuff other than the camera code. I had to trim a lot of things before i could get to the useful part.

    Second,
    i still don't know if it's an internal bug or real lack of memory for the application, but,
    most of the times when i use the Qt Camera with the OpenGL graphics system, it has problems
    displaying the frames.
    It complains about not being able load the frames as textures (since OpenGL is being used),
    displaying the "GL_OUT_OF_MEMORY error" on debug mode.

    Other than that, the Camera API looks fine.

  5. #5
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    Re: Qt Imaging/Camera APIs and competition - feedback requested

    Hi Fred

    Thanks for your feedback. I'll be packaging it all together to send to the experts at the end.
    Quote Originally Posted by fred.duarte View Post
    Second,
    i still don't know if it's an internal bug or real lack of memory for the application, but,
    most of the times when i use the Qt Camera with the OpenGL graphics system, it has problems
    displaying the frames.
    It complains about not being able load the frames as textures (since OpenGL is being used),
    displaying the "GL_OUT_OF_MEMORY error" on debug mode.

    Other than that, the Camera API looks fine.
    --- from the author of the camera example ----
    Sadly, for N8 or those other phones with only 32 MB of gfx memory it isn’t hard to run out of memory. Maybe you have some other graphics resources in the UI that consume the memory or there might be running some other processes in the phone that hasn’t freed the memory.

    The amount of graphics memory can be queried with this code, this might be handy for the debugging purposes. The code prints to the debug output the amount of total and used memory of the gfx memory in the device.
    http://projects.developer.nokia.com/...rofilingdata.h

    The code also requires egl library to be added to the .pro file:
    LIBS += -llibegl

    Here is the complete project file of the Qt Camera Demo:
    http://projects.developer.nokia.com/...camerademo.pro

  6. #6
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    Re: Qt Imaging/Camera APIs and competition - feedback requested

    The competition is now complete. Is there any more feedback you'd like to post on our imaging APIs before we pass on the feedback?

  7. #7
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    Re: Qt Imaging/Camera APIs and competition - feedback requested

    Hi Hamish,

    I realize that I am a couple of weeks late here, but it would be great to have the QCamera shutter speed access that one has with Harmattan on Symbian Belle. Right now in QML for Symbian, I can read the Shutter Speed but not write it. I am currently working on a camera app for the N8 & 808 PureView and would love to have access with Symbian to all the Qt Mobility Camera classes that Harmattan can access.

    Thanks!

  8. #8
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    Re: Qt Imaging/Camera APIs and competition - feedback requested

    Hi Msjen

    QML Camera API is as far as I know generic for both Symbian and Harmattan. So I'm a bit confused - are you saying that there is a method on Harmattan QML Camera class to set the shutter speed that is not on Symbian, or are you saying that there is such a method, but it only works on Harmattan? Or something else?

    Regards
    Hamish

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