[Interest] About usb cameras

[Jason H]

You got it! Thanks for the example!! :-)



________________________________
 From: Josiah Bryan <josiahbryan at gmail.com>
To: Jason H <scorp1us at yahoo.com> 
Cc: Lopes Yoann <Yoann.Lopes at digia.com>; "evazquez at grm.uci.cu" <evazquez at grm.uci.cu>; "interest at qt-project.org" <interest at qt-project.org> 
Sent: Tuesday, September 17, 2013 10:04 AM
Subject: Re: [Interest] About usb cameras
 


I created a class I called "VideoSurfaceAdapter" which inherits from a QAbstractVideoSurface which allows me access to the raw frames. See https://code.google.com/p/livepro/source/browse/trunk/gfxengine/QtVideoSource.cpp for the code.

Basically, in supportedPixelFormats() I return the formats I'll support, and then in present(...), I do the conversion using QImage - the code is all in the link above.

I hope this helps - forgive me if I misunderstood your problem.



On Tue, Sep 17, 2013 at 9:52 AM, Jason H <scorp1us at yahoo.com> wrote:

Thanks, but I am still not clear. 
>
>
>If I subclass QAbstractVideoSurface  (video probe is out - I need it on Windows) How do I get it into a QImage/Pixmap? 
>I am guessing that I would set the pixel format for it to be the same as for QImage? According to the that logic and the docs, there are a few formats that will work:
>Format_ARGB32, Format_ARGB32_Premultiplied, Format_RGB32, Format_RGB555, Format_ARGB8565_Premultiplied
>
>
>
>But will Qt do the conversion (if so how? lines of code please!). Do I tell the video source to give me a format? Does that format have to be supported by the device?
>
>
>I don't mind updating the screen, as I will be generating an overlay. and pushing that to the screen. 
>
>
>Thanks!
>
>
>
>
>
>________________________________
> From: Lopes Yoann <Yoann.Lopes at digia.com>
>To: Jason H <scorp1us at yahoo.com> 
>Cc: "evazquez at grm.uci.cu" <evazquez at grm.uci.cu>; "interest at qt-project.org" <interest at qt-project.org> 
>Sent: Tuesday, September 17, 2013 7:18 AM
>
>Subject: Re: [Interest] About usb cameras
> 
>
>
>On Sep 16, 2013, at 5:46 PM, Jason H wrote:
>Can someone tell me how to grab a frame and what is needed to be done to get to the point where I can do image processing easily? 
>
>With the C++ API you can use QVideoProbe (http://qt-project.org/doc/qt-5.0/qtmultimedia/qvideoprobe.html). Though, with a camera source, it will currently work only on Linux with the GStreamer backend. The frames can be in any format, including an OpenGL texture, and you'll have to to convert it to a QImage yourself if it's what you want to do.
>
>
>You can also subclass QAbstractVideoSurface (http://qt-project.org/doc/qt-5.0/qtmultimedia/qabstractvideosurface.html). It will work on all platforms and you will be able to specify the format of the received frames with supportedPixelFormats(). You will also have to take care of showing the frames on screen youself...
>
>
>Yoann Lopes
>Senior Software Engineer - Digia, Qt
>Visit us on: http://qt.digia.com
>
>
>_______________________________________________
>Interest mailing list
>Interest at qt-project.org
>http://lists.qt-project.org/mailman/listinfo/interest
>
>


-- 
Josiah Bryan
765-215-0511
josiahbryan at gmail.com 
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