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Create an open source camera stack for mer

asked 2013-12-30 11:39:36 +0300

crevetor gravatar image

I'd like to discuss the possibility of creating an open source camera stack for mer based on FCam and Gstreamer.

My idea would be to use gst-nokia-videosrc (https://gitorious.org/maemo-multimedia/gst-nokia-videosrc) from Meego and replace omap3camd with an fcam-based solution.

Pros :

  • Fcam is already functional and gives functionnalities such as autofocus, auto white balance, etc
  • Fcam is modular and only the camera drivers would need to be written
  • Gstreamer is the solution used by mer
  • gst-nokia-videosrc contains everything needed on the gstreamer side and hooks into the closed source libomap3camd
  • Once done, the community could improve to add new features such as oversampling, panorama support, etc


  • The targeted cameras need a good linux kernel driver that exposes the right controls
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This should go to Mer project for consideration?

Jukka ( 2013-12-30 15:45:46 +0300 )edit

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answered 2014-01-31 19:03:25 +0300

MSameer gravatar image

I don't think this really belongs here.

You can not replace omap3camd because it contains all the 3A algorithms as well as the high quality image capturing unless you will write a replacement (or live with bad image quality)

The other issue is that the algorithms there are tuned for N9 camera HW so it has to be adapted to other HW.

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Well you can get the 3A stats out of the omap3 isp and that's enough to process images yourself. As for high quality image capturing I don't know what you're refering to. In any case the goal would be to make fcam do the work that omap3camd did (focusing, white balance, etc)

crevetor ( 2014-02-01 04:16:28 +0300 )edit

Which means you will have to reimplement the 3A algorithms. It's not impossible but it's also not easy.

Here is how subdevsrc captures the actual image: https://gitorious.org/maemo-multimedia/gst-nokia-videosrc/source/57d27d0adafabb02671fb8ee448daa9214229b89:gst/subdevsrc/libomap3camd_calls.c#L1867

MSameer ( 2014-02-01 04:25:17 +0300 )edit

They are already implemented in FCam (if you're talking about auto-focus and auto white balance). Here is a shot I took with my N950 through fcam (not omap3camd involved), looks pretty good to me : http://t.co/6HxVqIm6

crevetor ( 2014-02-01 04:35:13 +0300 )edit

Since I am apparently missing details. I'd like first to see how you achieved that (A nano-howto is enough) :)

MSameer ( 2014-02-01 05:12:51 +0300 )edit

The code for fcam with N950 support is here https://gitorious.org/fcam-n950/fcam-n950/source/cb16a1036745fb26670a244c00c60885822b802a: . If I recall correctly you had to setup the v4l pipeline using media-ctl and then you were able to run example1 which would give you 2 raw shots and a jpg shot.

crevetor ( 2014-02-01 13:10:42 +0300 )edit
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Asked: 2013-12-30 11:39:36 +0300

Seen: 402 times

Last updated: Feb 01 '14