6-18-07

Last week I looked into software which would work well with the frame grabber that I installed in the m25 machine. I wrote up some notes on the hardware and useful software which I have found:

I. Features

• [http://www.integraltech.com/FileDownloads/fe8349_FB_SpectrimLite.pdf Official Info Sheet] on the Integral Technologies FlashBus Spectrim Lite

Notable excerpts:

• 16 MB of memory
• S-Video and BNC inputs
• Good support for Windows but not much for Linux or anything else
• Max. resolution of 640x480 in NTSC mode

II. Installation

Video For Linux (V4L) installation software can be found on Integral Technologies's website: http://www.integraltech.com/FileDownloads/e2245e_spectrim-v4linst-v2.5.tgz

Compiling and installing this software should be enough to get the card up and running. The release notes state that the software has been tested on Fedora Core 2 and 4 but it also works on FC3 (albeit with some bugs).

After installing the software, make sure to specify the amount of memory available to the card in grub or lilo as described in the README.mem file! Otherwise, V4L programs (including the test programs that come with the card's software) could crash the computer. Also, make sure to run the startFbspSupt script included the support directory. This program will output a "test.bmp" file so you can tell if your card is working.

III. Software

• There are a lot of V4L applications which have a large number of dependencies and which crash a lot. The better ones I have found for the Spectrim are:

1. videodog ([http://paginas.terra.com.br/informatica/gleicon/video4linux/videodog.html Homepage])

videodog is a simple capturing utility which is good for capturing single images from the frame grabber. It has some useful features, like optional JPEG capture and timestamps in the image, as well as optionally automatically timestamped file names so that it can be run easily from scripts (including Matlab). The loop capture has a bug which makes it output junk to the terminal, and the normal capture has a bug where there are invalid calls to the V4L API. I think these are both driver problems, but the single capture / auto-timestamped capture works. If the output is suppressed by appending ">> /dev/null 2>&1" to the end of the command it seems to work faster (i.e., looping the timestamp capture will not capture images as many times as videodog is called; it seems like commands will be lost when videodog is busy writing to stderr/stdout or capturing images).

videodog is a fairly simple program to edit. A major bonus is that it hardly has any dependencies (I think the only external dependency is libjpeg which seems to be standard), so compiling it should be easy.

2. xawtv ([http://linux.bytesex.org/xawtv/ Homepage])

xawtv is a TV application which allows you to view a live feed of the framegrabber's input, as well as capture still images in bitmap (ppm) or jpeg formats of the live feed. It has video capture capability, but as far as I can tell right now that feature either requires a lot of memory or the V4L software for the Spectrim is pretty shoddy since anything but low-framerate MJPEG capture ends xawtv in a segmentation fault or outputs a lot of errors.

xawtv comes with streamer, a program like videodog but one more prone to crashes. streamer should also allow you to capture video from the command line, but it crashes like the video capture from the xawtv GUI (probably because xawtv uses streamer to capture video and images).

motv has a cleaner GUI than xawtv itself, and comes with the whole xawtv suite of programs available on the website above.

Test Image

Here is a sample image taken at full resolution (640x480) in 24-bit color (although the video feed is black-and-white). The image is oversaturated at some points and the image is noticeably noisy. attachment:out.png

6-28-07

More Linux/hardware notes: before I forget, there is a SourceForge project which supports both the Agilent 82537A/B (the grey USB adapter) and the 82530B (the PCI card). It's called linux-gpib and it will hopefully work: http://linux-gpib.sourceforge.net/ .

It would be wise to read the documentation for supported GPIB interfaces first since the USB device needs to have its firmware flashed and messing that up would probably brick it. If I have extra time, I'll get around to this.