qnr has tried it with some success, doing it the hard way through Gimp. But it would be better to do it automatically...

The trouble is getting the pictures; imagemagick or netpbmtools will average. With netpbmtools, particularly, filtering 4 images is easy; interlace the 4 together (horizontally and vertically), then median filtering or similar, then scaling back to original size. I think this would provide very good results.

if we disabled the screen during video recording do you think it could record at a higher frame rate or at a higher bitrate since less cpu would be used?

Ok some news about VLC and streaming from the NIT camera.

I have spent a couple of hours installing -- well, shoehorning -- the Debian armel VLC to see if I could get it to display the camera.

My conclusion: it looks like you should use the pvr:// device not the v4l:// device.

I have yet to get past the "pre buffering" stage (VLC finally fails with cannot pre fill buffer), but it at least finds the device and seems to be getting access to it.

Does anyone with the vlc compiled for maemo still have their copy? Can you try the pvr:// device?

What about using mencoder to grab a few frames of video (at 15fps, that's 66.666 msecs per frame, so 200 msecs of video gives you 3 frames, 333 msecs for 5 frames, etc) using the -endpos parameter?

Image Magick supposedly can read uncompressed AVI (the default format for mencoder), and you could extract the needed images from that file... theoretically...

EDIT: The following code gave me 8 frames of 640x480 uncompressed video in a file called pics.avi. I can play it with mplayer.

Note that you MUST record to your mmc cards because the tablet cannot write to internal flash fast enough.

EDIT2: ImageMagick doesn't seem to recognize the avi produced by mencoder. Sigh.

Hmmm, averaging or whatever may be good in theory but to be practical the tablet would have to be on a tripod for *every* shot no? IIRC another method for cleaner images might be to build up a noise-map (don't know correct terminology) over several/many frames with the camera covered and then use this info to clean-up single shots?

Qole: Beautiful; I'll work on that. Bet I can get something.
Muki: Called dark-frame exposures, and yes, that's a useful technigue; perhaps we should do both, but I'm much more confident in knowing what I'm doing with averaging.

The tablets (N800, anyway, since you can swing the cam to a useful angle) have a built-in stand, so no tripod as such required. Naturally, this requires a delay from intitiating the command till the frames are taken so any movement from tapping the screen dies out, but we'll probably have that whether we like it or not...

ImageMagick should recognize Motion JPEG. You can enforce recording in this format.

Where can I get ImageMagick and mencoder for N800? I have mplayer 26 package but without mencoder.

My goodness. That was easy.

And out pop 8 jpeg pics!

You can also use png, gif89a, tga, and pnm as output formats.

I don't want to do any compression during capture; that's essential.

Maemo ImageMagick is here at Anidel's blog. Google ("maemo imagemagick") found me that one.

There are (at least) two threads with mencoder binaries linked in them, I'm using Bundyo's 1.0rc2 mencoder from this thread. The forum search function ("mencoder compiled") found that one for me.