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Video capture hints needed

Discussion in 'Software' started by alangeering, Jan 21, 2005.

  1. alangeering

    alangeering Theatre Tech (AV)

    I'm trying to get a PC to capture from 2 sources simultaniously (2 very different PCI cards).

    At the moment installing one disables the other... which is annoying.

    Assuming I get past that obstacle, are there any helpful hints from people who've used multiple capture cards?

    Alan G
  2. Stickman

    Stickman New Member

    er, I'd normally ask somebody like you a question like that.....


    what op-sys are you running?

    I've seen (as opposed to used) winXP Prof use three capture devices simultanously, but, have no idea if they were PCI or USB based.... is there a limit under VFW?

    I also remember trying to use 2 capture cards under win98 (years ago) and never managed to get it working.

  3. solly

    solly New Member

    I heard once that you could use firewire capture and a usb capture at the same time with ARKAOS.
  4. djMidnight

    djMidnight Code Poet

    As long as you're using the appropriate DirectShow calls everything should work fine. Everything runs async, which makes "triggering" the capture fun, but there are ways around that too.

    Midivid GPU has a pretty solid capture setup that will host as many cards as you have plugged in, in whatever resolutions you choose, alll running simultaneously, and it handles DV too. It didn't require any special code to make it that way, assuming you don't normally consider my code all that special. :)

    Feel free to PM me, and JohnnyLocust is another good guy to pester with DirectShow questions. I can send you the DShow CaptureTexture sample I mentioned if you don't have it.

  5. alangeering

    alangeering Theatre Tech (AV)

    THanks guys, I may be in contact soon.

    Video capture card 1 captures RGBHV/RGBS etc. and DVI video streams up to 1600x1200 BUT uses a VfW driver.

    Video capture card 2 captures Composite/S-Video (PAL or NTSC) using a WDM driver.

    It seems that as soon as I install card 2 and the WDM driver the old VfW device dissapears of the map.

    It's still there and functioning in devicemanager, just not showing in any lists of capture devices.

    I'm gonna have to do a little more research.

  6. Stickman

    Stickman New Member


    I seem to remember reading (in a readme.txt somewhere) that VFW and WDM do not co-exist.

  7. XPz

    XPz New Member

    Yes WDM and DShow can coexist.
    I have a friend using ArKaos with two capture cards: one Pinnacle with analog input and another strange english card with two VGA inputs (very good quality). He also tried adding a FireWire input full resolution and there the bus seems to be full because all begins to get slower (maybe we get 3 frames for 4 we should get or something like that).

    I think it should also work in other softs.
  8. cat

    cat Senior Moments

    What are these vga capture cards? Sounds intreaging
  9. alangeering

    alangeering Theatre Tech (AV)

    Can you please expand on this:
    are you saying that VfW and WDM can co-exist... because that's what I need to know.
  10. XPz

    XPz New Member

    Some cards have VfW and WDM drivers. Some have just one I think, not too sure.

    I'm not too sure but I think applications can open both...

    Does someone know more about it ?
  11. johnnylocust

    johnnylocust R3dN3cK \/_/

    Beats the hell out of me. What brands are they?

    One possibility is the one that has a WDM driver is simply wrapping a VFW driver. But that doens't make any sense, because directshow will automatically do this for cards that only have a vfw driver. Have you downloaded the most current drivers for you capture cards?
  12. alangeering

    alangeering Theatre Tech (AV)

    I've now got a little suspicion that each time a driver is installed it uses a registry entry to call itself "THE" WDM capture device rather than prlaying fair and calling itself "A" capture device.

    Yeah, you're right, all VfW should be wrapped by VfW2WDM wrapped.

    Cards are:
    A. Unigraf UFG-03 (HiDef version)
    B. Winnov Vidium PCI (Standard Defenition over S-Video or Composite)

    I'll do a little more checking, could jsut require a little registry hacking, or could be more fundamental.

    Eventually I will have to deal with bandwidth over PCI bus issues but for now I just want the 2 cards working.

  13. Stickman

    Stickman New Member

    I'll have a look around one off my old PC's and see if I can find the documentation that I remember reading... it might well be specific to the drivers for that particualr card, but, it definatley indicated that I had to un-install VFW if I wanted to use WDM.

    I think the point you made re the registry is probably closer to the mark / more than likely, or, something deeper within the app. code / chipset of the card (ie, one of the cards taking control).

    No chance of finding WDM drivers / solution for the VFW card???

  14. alangeering

    alangeering Theatre Tech (AV)

    Yep, registry hack solved the problem

    Each card was saying "I am THE capture card" by modifying the following:

    Address: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32
    Key: MSVIDEO
    Type: REG_SZ
    Value: UFG.dll

    This is what it looks like with Card1, when I installed Card2 the Value was changed to refer to it's capture driver.

    The solution:

    Make a key: MSVIDEO1
    Give it the value of one of the capture drivers (a DLL usually). Then run a program that does video capture. You may get an eror at this point. Restart windows and all should be fine.

    It's odd, but it seems you have to remind windows that it can have more than one device and once done, it's had no problem in adding quite a few more.

  15. alangeering

    alangeering Theatre Tech (AV)

    Edited to make mroe clear:

    For thoe interested:

    800x600, 12.7fps, RGB24, 18.395 Meg/Sec

    I've set the fps for reasons of getting enough interframe time for processing.

    Generally the max fps (if you deregulated the capture rate) is limited by PCI bus bandwidth. All frames transfered from card to system memory in RGB24, but driver will output RGB32 and RGB5:5:5 if requested (not a difficult thing to do).

    At my settings Processor near idle and ATA100 7200 rpm HDD not stressed.

    Good news: if the frame rate is considdered acceptable for an application, there are plenty of spare processor cycles for image processing / compression.

    HDD speed can be a bottlekneck... until you add some compression, then the CPU can be the bottlekneck. It's a ballencing act between these two.
    The only thing you cant change is the PCI bandwidth.

    I'll be doing a little bit of playing later.

  16. djMidnight

    djMidnight Code Poet

    You should see if it's possible to get the card to output in YUY2, UYVY, or I420 modes. NTSC & PAL don't provide a signal in RGB anyway, so having full RGB per pixel is overkill.

    Grabbing YUY2 or UYVY will be pulling the native NTSC signal back to the machine, and it only consumes 2/3 the data rate.

    I420 is slightly lossy in the chrominance info, but you'll only be using 1/2 the data rate of RGB.

  17. alangeering

    alangeering Theatre Tech (AV)


    I'm working with an RGB source, and encoding in RGB codec.

    I'm actually not going anywhere near PAL and NTSC at the moment.

    Eventually my project may branch in that direction but most of it is pretty boring screen capture (i.e. ppt, excel, matlab, etc.) stuff at the moment. Accuracy is the most important criteria (i.e. reading the 10 or 12 pt text).

  18. Meierhans

    Meierhans Spezialmusik

    This VGA capture board is a really nice thing. DVI-IN! Wow! How much is it?

    I`m a bit curious about your 12,5 frames. How can it than be possible to transmit full PAL (even 3 times) with full 25 FPS via PCI Bus? I don`t know enough about my hardware internals to say if there is a controller for every PCI-Slot, but even one 720*576 stream is close to 800*600.

    Specs from their page:
    1600 x 1200 27 fps max
    1280 x 1024 40 fps max
    1024 x 768 66 fps max
  19. alangeering

    alangeering Theatre Tech (AV)


    the fps needs a little explanation

    I've set this fps in the capture app as I don't have a didicated disk arry (yet) just one ATA100 HDD.

    So take the max fps I could do, then devide by 2, and then you get a number of fps that you know will be totally stable & give you enough processing time between frames.

    Once I've got my processing modules sorted I'll see how many fps they can cope with (after optimisation) and the increase the fps of the capture.

  20. alangeering

    alangeering Theatre Tech (AV)


    Struggling to get higher frame rates, though able to get higher data rates... this has me puzzled.

    last run 12.5 fps 1024x768 RGB24, 29.647 Meg/Sec (no frames dropped)

    in the run previous to this I tried to force 30 fps and ended dropping 50% of frames.

    I will need to do some more investigation.

  21. alangeering

    alangeering Theatre Tech (AV)


    Leaving capture rate undefined usually results in software choosing 12.7 fps.

    Setting manual fps is erratic.

    20 fps @ 1024x768 RGB5:5:5 will run for 20 seconds then start dropping frames (1 in 2).

    This seems like a storage issue.

    Lets see if the University will get me a nice drive array. (I need it, so they should).



    People wanting to use this card for realtime input, effecting, output (not capture) will probabaly achieve higher frame rates as they will not be saving to HDD.

    I've played around with it a bit, putting web cam image in bottom corner (PinP style) with alpha@80% etc. Just little tests to see what was possible, and it seemed to work smothely.

    Have not tested any VJ apps as this realy isn't within the scope of my project.

  22. Meierhans

    Meierhans Spezialmusik

    This is good news. How much does it cost?
    What kind of codec do you use to capture?
  23. alangeering

    alangeering Theatre Tech (AV)

    Costs: 1400 to 2000 euros depending on version (normal or Hi-Def)

    Codec: none (i.e. video is encoded as 24 bit RGB but there is no compression.)

    The card does not have any onbord compression schemes, if you want to compress then you do this in software.

    If the card had a good lossless (or weak lossy - I need lossless) compression scheme it would be more complicated but would get more out of the bandwidth of PCI and that available when writing to HDD.

    The downside to compressing losslessly on a card would be having to decompress in software before effecting /converting the video stream.

    The UFG design is great for anyone who needs accurate video capture from VGA or DVI (they make one that does PAL/NTSC as well).

    Frame rates at the moment (on my system) prevent me from recommending this device as a VJ tool... but if rates get over 50 fps whilst still not being too processor intensive then I would be very excited.

  24. Meierhans

    Meierhans Spezialmusik

    1400 Euros. :sad: For this money I get a completly new PC...
    For your capturing: Did you try the the common capture codecs in software to get higher framerates?

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