Camera, XO 1.5 vs XO 1

Chris Ball cjb at
Sat Apr 24 12:18:06 EDT 2010

Hi Tiago,

You don't mention which build you're using, and it's important because
we're still making many changes to the camera setup, so please do that
in future.

   > - XO 1 has slower response time in the video being shown.

I think this is probably

The 1.5 setup is capable of producing many more fps from the camera
than 1.0, and Record doesn't use a framerate limiter on the preview
window, with the result that you see a very high fps on the 1.5
preview window at the cost of so much CPU use that Record becomes

Daniel Drake's latest patches to Record add a framerate limiter to
its preview window, which will make 1.5 behave more like 1.0.

   > - XO 1 has a much brighter picture, which results in a
   > much clearer one.  Even with good surrounding light, the 1.5
   > shows a very dark image.

Don't know about this.  We do have some control over brightness/gain
in the kernel driver, I think.

   > - XO 1.5 record isn't saving more than 2s of video.  Was fixed back in os119, as far
as we know.

   > I thought that the camera sensor had been exchanged between
   > revisions but I've just checked and it's the same. What gives?
   > Software?

Yes, the sensor's the same, but the hardware and software interfacing
to it is different.

os121 (about to be released) should be able to record video well,
please re-test with that when it's out.

- Chris.
Chris Ball   <cjb at>
One Laptop Per Child

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