[Interest] Creating a video feed or overlay

[Jason H]

I've had mixed experiences with overlays, it all depends on the platform and where you insert yourself into it. (DirectX is bad)
I would try to avoid capturign/displaying QImages and QPixmaps. I'd try to keep it all in YUV, includign your overlay, for easy merging that can be done on a OpenCL implementation. However, if on a Linux you might get it for essentially free by sticking  widget on top of the video widget and making sure they are both GL implemented. 



________________________________
 From: Josiah Bryan <josiahbryan at gmail.com>
To: Lopes Yoann <Yoann.Lopes at digia.com> 
Cc: Tom Isaacson <Tom.Isaacson at navico.com>; "Interest at qt-project.org" <Interest at qt-project.org> 
Sent: Thursday, April 3, 2014 11:27 AM
Subject: Re: [Interest] Creating a video feed or overlay
 


Lopes -

I did a lot of live video work using Qt in a project I have on Google code: https://code.google.com/p/livepro/

I havn't tried it with Qt 5+, but it was all with Qt 4.8.

Let me know if you have any questions on that if you actually do look at any of the code.

Thanks!
-Josiah



On Mon, Mar 31, 2014 at 6:52 AM, Lopes Yoann <Yoann.Lopes at digia.com> wrote:


>On Mar 28, 2014, at 7:41 PM, Tom Isaacson wrote:
>
>> I'm working on an app that reads data from a sensor then displays it on a graph using qwt. This part is working fine but what we want to do now is create a video feed of the graph that can be displayed in other apps. We'd also like to add the graph as an overlay to a video feed from a camera. Is either of these possible in Qt, and if so where do I start?
>
>
>Qt is probably not the best solution to do this. You could get the raw video frames from the camera (using QCamera and QVideoProbe/QAbstractVideoSurface); if the frame is in RGB, you could easily convert it to a QImage and then use QPainter to draw the graph over it. From there you'll have to find another solution to set up a live feed from these frames, since Qt Multimedia doesn't provide any API to encode and stream video.
>
>Using GStreamer directly (we use it as backend on Linux) would probably be a better choice.
>
>However, for the app displaying the video feed, Qt is a perfect fit. QMediaPlayer or the QML MediaPlayer accept any URL.
>
>--
>Yoann Lopes
>
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-- 
Josiah Bryan
765-215-0511
josiahbryan at gmail.com 

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