Multi-Source Video Capture Cards for Unix? 27
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?"
PCI Busses (Score:1)
Multi channel PVR? (Score:3, Informative)
I would like to record two channels at the same time.
Tivos and digital receivers don't do this which is a real shame.
Re:Multi channel PVR? (Score:1)
Re:Multi channel PVR? (Score:1)
Re:Multi channel PVR? (Score:2)
The reason VCRs and PVRs can record while yuou watch another channel is that they use their tuner for recording, and then pass the signal through to the cable box/tv's tuner for viewing.
I don't know of any TV cards that have two tuners - maybe you could try two TV cards? Although I think software issues would get mighty hairy there, because as far as I know this is hardly an often-used application.
Re:Multi channel PVR? (Score:1)
Re:Multi channel PVR? (Score:1)
MJPEG card (Score:3, Informative)
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.
If you don't want to roll your own... (Score:4, Informative)
http://www.axis.com/products/cam_2460/index.htm
An easy alternative (Score:1, Insightful)
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...
wow can't believe you missed this (Score:3, Informative)
IntegralTech (Score:3, Informative)
Re:IntegralTech (Score:1)
4 Channel brooktree based grabber (Score:1)
Should work under linux. FPS will be low since it's one chip for 4 inputs. $179 AU.
Ellips Rio Full (Score:2)
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 [isr.uc.pt] 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.
Done this (Score:1)
If quality's not much of an issue... (Score:1)
Osprey 100 has four ins and linux drivers (Score:2)
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
8 "channels" - cheap. (Score:2)
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...
Multiple BT848/878s (Score:2)
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.