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Multi-Source Video Capture Cards for Unix?
An anonymous reader asks: "I'm curious as to what video capture cards are being used successfully by the linux user base. I need to capture screen shots from 4 video sources and collect the images in a manner that makes them easy to present in a web browser. A 4 input card would be nice! But I could always use a matrix switcher to grab frames from each source periodically. Matrix-Vision has a card - the mvDelta - that seems to work, but alas, they don't sell single units. What's out there? Who's using it? Any suggestions?"
Lots of PCI Busses!
http://www.freebsd.org
As an aside does anyone know of a multi-channel TV card?
I would like to record two channels at the same time.
Tivos and digital receivers don't do this which is a real shame.
Mouse powered Chips, Open source Processors and Lego
MJPEG card from linuxlabs i think. awesome hardware MJPEG processor on board and we're using it with 8 channel capture (8 cards in standard PCI slots). comes with linux drivers and a commercial linux editing suite. capturing 8 channels uses almost no CPU time thanks to the hardware video processor.
Our RAID array does the rest by using its on board i960 CPU to dump the data/do the RAID5 stuff (ICP Vortex with 256MB cache).
our CPU runs 80% idle capturing 8 channels of compressed video at full res, 24bits (its a p-3 800). dedicated processors rock.
Use this - it runs Linux, has four imputs and works.
http://www.axis.com/products/cam_2460/index.htm
Moneyed corporations, non-working 'poor' and criminal prisoners are turning productive citizens into tax-slaves.
If all the screenshots don't have to be taken at the same time why not use some cheap channel modulators to put the video signal into a coax line similar to cable TV? Then you can capture each channel right after another. If it's for the web it probably doesn't have to be of exceptional quality or be 30 fps. I just bought a STB PCI TV tuner off of eBay for $20 with shipping which I am going to try something similar with.
If you want the absolute best quality and have plenty o' PCI slots, you be'd better off with more cards. BTW, if all you want is to take screenshots don't waste your money on more expensive cards with hardware MJPEG support unless you are running this on a Pentium 133 or something like that. Even then...
the mvSIGMA-SQ - by matrox - http://www.matrix-vision.com/eindex.htm - it has 4 independant grabbers on one card.... hmm are you high?
Only 'flamers' flame!
Check out Integral Tech (.com). They support Linux and have some frame grabbers with 8 inputs.
Should work under linux. FPS will be low since it's one chip for 4 inputs. $179 AU.
Be ot or bot ne ot, taht is the nestquoi.
Multi source framegrabber if a maximum of two simultaneous colour sources or six simulaneous b&w sources and six channels maximum works for you go for the ellips rio full framegrabber. http://www.ellips.nl
They told me they were wanted to develop a linux driver but were unable to do so (it's a small company) and would happily assist anyone interested in developing it. Currently this guy is developing a linux driver that seems to have the basics running. The card itself is a wonderfull product and it seems to work flawlessly in all systems I've tried.
I needed to make a portable webcam server on wheels once. I just put 4 Haupauge WinTV cards (bt848) cards in a box and I was done.
`fortune -o`
If you want video editing / processing fo UNIX, SGI is your route.
As far as Linux goes, Linux is NOT UNIX.
Remember? GNU/Linux
Gnu's Not Unix?
sometimes slashdolts are just amazing.
...why not make use of a USB hub and a Hauppage WinTV-USB? You should be able to attach to multiple devices (/dev/video0, /dev/video1, etc.), I just don't know what kind of quality you can expect nor if there are Linux drivers available for it (yet).
Trolls lurk everywhere. Mod them down.
Take a look at:e y100. html
http://www.viewcast.com/products/osprey/ospr
It's a BT878 based card which has four ins (3 composite, one S-video). You can only use one at at time, but they're software switchable. They claim to have linux drivers as well.
Jeff
2) 8 cheap video cameras
3) PC with parallel printer port
4) Homebrew switcher (described below) hooked to parallel port
5) Custom software (for whatever OS you use) to control the switcher.
Build the switcher by using 8 RF relays, or by using an analog multiplexer/switching chip. If you go the relay route, hook it up to the parallel port by tying each data output line via a 1K resistor to the base of an NPN switching transistor. Connect the emitter to ground (ie, negative on your relay power supply, and the ground line on the parallel port). Connect the collector to one side of the relay coil, the other side of the coil goes to your positive of the relay power supply. Connect a diode across the coil in the proper direction to keep the coil from spiking the transistor and killing it. Hook up the video to each relay, have the shielding of the video cables be VIDEO GROUND (do NOT hook this up to the other ground unless you want a crappy signal).
If you want to get fancy (and be safe), add a buffer chip (hex buffer or similar) between the inputs to the transistor drivers and the parallel port data lines. Also, you may want to add logic circuitry to allow only one relay to be latched at a time (a binary to decimal conversion IC would do here, then you would send the byte to represent the relay wanted to be switched, and one of "N" lines on the chip would be brought high). You only want one camera active at a time because the extra signals could cause problems with the other cameras as well as cause "ghosting" effects on the final output.
All in all, such a switcher would be easy and cheap to create, and could be mounted inside the PC if you wanted (on a card, or in a drive bay, for instance). I am thinking maybe $20.00 in parts.
BTW - don't go by the directions I gave above - I can't be certain my circuit is completely right, since I don't have such a thing "memorized" - search Google for parallel port interfacing before actually building the thing. I will take no responsibility for what I described should it fry your PC...
Reason is the Path to God - Anon
I belive up to 4 BT848s (maybe more) are supported in the bt848 drivers for linux out of the box.
/dev/video0, /dev/video1, /dev/video2,/dev/video3.
Just put 4 capture cards in the machine, and grab from
This is probably the cheapest way to do it, as a simple BT848 capture card without tuner only costs about $NZ80 ($US30 or so)
Depending on the resolution at which you grab this will likely saturate your PCI bus and/or your disk controllers bus, so don't expect to be able to capture 4x full-PAL/NTSC to that old 2GB IDE drive.
However, 4x 320x240 should be easily manageable on a P2-class machine, I would think. If you want to compress th einput using something like FAME, then look at more CPU.
A 1GHz+ Athlon with 7200rpm/ATA-100+ IDE should work OK.
A 2GHz+ P4 with 10,000rpm SCSI RAID would handle more channels in realtime, possibly even uncompressed, though you better have a fat wallet to afford the disk drives.
I gots ta ding a ding dang my dang a long ling long
If you want to grab images from cameras, another option is a camera with a network interface like those made by Axis. Then you just use wget or ftp to grab images from each. If the network gets too busy, you can also put more network cards in the server and have fewer cameras on each of those separate networks.