Dan Ritter <d...@randomstring.org> writes:
> fswebcam is a package that captures images from V4L2 devices.
> It's command-line driven and has a few useful features like
> resizing, averaging multiple frames, and skipping early frames
> for devices that take a while to focus. It writes JPEG or PNG.
>
> Remember to make yourself part of the video group.
Oh, yes. Interestingly enough, I am part of that group. I was
going to do that and first did groups martin and, what do you
know, I'm already in the group. How I got there I do not know.
So, here's what has happened and it's all good so far.
After much soul-searching which should precede any outlay
of 400 US Dollars, I bit the bullet and bought an Epiphan
AVIO-HD.
The linux kernel immediately recognized it and then the
fun started.
I finally got fswebcam setup after some fumbling around
an plugged the VGA cable in to the appropriate socket on the
video card.
I captured a picture and sent it to my wife's iPhone and
she said it was just a black screen. I knew it should have
basically been a screen shot of my Linux box since I was logged
in via tty1, I think, but it's the first console anyway.
That was yesterday afternoon when the AVIO arrived so
this morning, I moved the VGA connection to another Linux box
whose VGA card only has one output.
Interestingly, the AVIO-HD generates frames of nothing
even when the VGA cable is disconnected and hanging in space or
lying on the table. The JPG files are about 4 KB in size and
fswebcam says it harvested however many frames one asked for.
I made this discovery the way I discover a lot of stuff,
sort of like oh wow! It makes the same length file plugged in as
it is making with the end of the cable in my hand.
When plugged in to the VGA socket on the other Linux box,
I was encouraged because the size of the captured frames always
showed about 10 K instead of 4 K.
I also downloaded tesseract and several other utilities
such as sane plus a jpg from a site which has sample scans taken
with real cameras and paper pages.
The tesseract utility flawlessly converted the sample jpg
in to ASCII text so I tried that
other Linux box's VGA port. This certainly looks like not much
of anything but I was happy to get it:
Debian GNU/Linux 10 audios tty
audio3 login: [43431.294393] print_req_error: 1/0 error, dev fd0, sector 0
[43431.338633] print_reqerror: 1/0 error, dev fdo, sector 0
I guess I may have stuck a blank disk in to the drive or
something as it looks like it is complaining about being unable
to read the floppy disk. It also may be left over from booting
as the floppy is the first boot source and empty.
I also have a small device that closely resembles an
infant-sized PC tower that I payed a whole Dollar for at a flea
market. The back panel has two usb ports, two RS-232 DB9 ports,
audio jacks, a DB25 printer port , RJ45 Ethernet socket
and a VGA socket just like PC's of 15 or 20
years ago. If you plug headphones in to the Line-out jack, you
get a short beep after pressing the power button. What would
it's VGA jack say?
Acute Network Technologies
ThinCast 5000
I looked that up and it is a client terminal-like device
that is meant as a work station in some institution.
Depending on how many resources it has, one might be able
to load a Linux kernel but I am not holding my breath.
Anyway, I want to thank everybody who supplied helpful
information. The tesseract OCR, so far, exceeds my expectations
of it's ability to decode the VGA text from just 1 frame of
capture. I think I can do BIOS setups, probably much more
slowly, but still it beats wasting other people's time especially
when one runs in to a situation where stuff isn't quite right and
one has to revisit the same task several times before things
shake out correctly. It is also possible to save the screen
shots for posterity which is nice if you haven't done some task
in a year or so and are having to remind yourself what you did.
By the way, the black screen on the first Linux system
was due to the fact that the video card has a VGA socket and
possibly a DVI socket. The video is on the DVI socket most
likely and the VGA socket has no signal, explaining the black
screen of nothing.
Thanks to all!
Martin McCormick
