Hi!

quoted

I think libv4l itself has algorithms to control at least some of these. It
relies on the image data so the CPU time consumption will be high.

AFAIR Laurent has also worked on implementing some algorithms that use the
histogram and some of the statistics. Add him to cc list.

http://git.ideasonboard.org/omap3-isp-live.git

That's outdated and might not run or compile anymore. The code is
more of a

Lets see, it compiles with this hack:

index 6f3ffbe..935f41d 100644

--- a/isp/v4l2.c
+++ b/isp/v4l2.c

@@ -292,7 +292,7 @@ struct v4l2_device *v4l2_open(const char *devname)
         * driver (>= v3.19) will set both CAPTURE and OUTPUT in the
         * capabilities field.
         */
-       capabilities = cap.device_caps ? : cap.capabilities;
+       capabilities = /* cap.device_caps ? : */ cap.capabilities;
 
        if (capabilities & V4L2_CAP_VIDEO_CAPTURE)
                dev->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

I can try to run it, but I guess I'll need kernel with camera support.

pavel at n900:/my/omap3-isp-live$ LD_LIBRARY_PATH=isp ./snapshot
media_open: Can't open media device /dev/media0
error: unable to open media device /dev/media0
Segmentation fault (core dumped)

I tried again on kernel with camera:

pavel at n900:/my/omap3-isp-live$ LD_LIBRARY_PATH=isp ./snapshot
error: unable to locate sensor.
Segmentation fault (core dumped)
pavel at n900:/my/omap3-isp-live$

Here's the fix for coredump:

diff --git a/isp/subdev.c b/isp/subdev.c
index 9b36234..c74514e 100644
--- a/isp/subdev.c
+++ b/isp/subdev.c

@@ -75,6 +75,8 @@ int v4l2_subdev_open(struct media_entity *entity)
 
 void v4l2_subdev_close(struct media_entity *entity)
 {
+  if (!entity)
+    return;
        if (entity->fd == -1)
                return;

Let me investigate some more.

proof of concept implementation, but it could be used as a starting point. 
With an infinite amount of free time I'd love to work on an open-source 
project for computational cameras, integrating it with libv4l.

For the record, I pushed my code to

https://gitlab.com/pavelm/fcam-dev

Best regards,

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html