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I have a USB Frame Grabber with core EM2820 Default linux driver detect this with em28xx but with vlc when I put dev/video0 give me an error: [0x7fdab80011c0] v4l2 demux ...
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  1. #1
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    RHEL6 Usb VideoGrabber


    I have a USB Frame Grabber with core EM2820

    Default linux driver detect this with em28xx but with vlc when I put dev/video0 give me an error:

    [0x7fdab80011c0] v4l2 demux error: cannot open video device 'dev/video0' (No such file or directory)
    [0x7fdab80011c0] v4l2 demux error: cannot open video device 'dev/video0' (No such file or directory)
    [0x7fdab8004200] v4l2 access error: cannot open video device 'dev/video0' (No such file or directory)
    [0x7fdab8004200] v4l2 access error: cannot open video device 'dev/video0' (No such file or directory)
    [0x7fdac8000c70] main input error: open of `v4l2://dev/video0' failed: (null)

    any ideas?

  2. #2
    Linux Enthusiast Mudgen's Avatar
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    Is that just a typo, "dev/video0"? Looks like it should be "/dev/video0".

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    Linux Guru Rubberman's Avatar
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    Yeah. I think Mudgen has it right in that it should be /dev/video0 and not just dev/video0. You also might want to verify that the device is properly registered as /dev/video0. However, if you have other video hardware, such as another webcam, installed, it may be video0 and your device would then be /dev/video1, for example. When I plug my USB web camera into the system port, it shows up as /dev/video0 since there are no other video devices installed on the system.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

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    Unhappy RHEL6 Usb VideoGrabber

    Quote Originally Posted by Rubberman View Post
    Yeah. I think Mudgen has it right in that it should be /dev/video0 and not just dev/video0. You also might want to verify that the device is properly registered as /dev/video0. However, if you have other video hardware, such as another webcam, installed, it may be video0 and your device would then be /dev/video1, for example. When I plug my USB web camera into the system port, it shows up as /dev/video0 since there are no other video devices installed on the system.
    Thank's with "/dev/video0" i see the webcam video but when unplug webcam and plug the frame grabber this don't work. Surfing on internet i fonund the driver for em28xx and is in .c but when try to compile give me errors..

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    Linux Enthusiast Mudgen's Avatar
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    Quote Originally Posted by Lorius View Post
    Thank's with "/dev/video0" i see the webcam video but when unplug webcam and plug the frame grabber this don't work. Surfing on internet i fonund the driver for em28xx and is in .c but when try to compile give me errors..
    Good luck. You're trying to do fairly cutting edge stuff with a distribution that's built for stability. RHEL6 is roughly equivalent to Fedora 9, and is never going to be as new-featured as a current Fedora or other bleeding edge distro.

    I'm too lazy to depend on custom-built drivers. You have to rebuild them whenever you update your kernel environment.

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    Linux Guru Rubberman's Avatar
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    How did you try to build the driver, and where did you get it from? Was this where you got the driver? How to Obtain, Build and Install V4L-DVB Device Drivers - LinuxTVWiki
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

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    Linux Guru Rubberman's Avatar
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    I just looked, and the current kernel for RHEL 6.x is 2.6.32-220.4.1, and it has by default, kernel modules built for the EM28xx class USB framegrabbers. However, the latest source code for these is available from the LinuxTV.org web site. I'm building the entire kernel with the new driver code and will report back once it has finished.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

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    Linux Guru Rubberman's Avatar
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    Ok. There is a problem building the latest drivers with the current kernel. I get a bunch of this sort of error:

    fs/compat_ioctl.c:2486: error: invalid application of ‘sizeof’ to incomplete type ‘struct dvb_frontend_parameters’

    If this is what you were trying to do, then it would seem understandable that you were having compile errors. I know this kernel source built before I copied in the new V4L driver code, as I did it just last Friday. I'll see what happens with a slightly earlier version.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

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    RHEL6 Usb VideoGrabber

    Quote Originally Posted by Rubberman View Post
    Ok. There is a problem building the latest drivers with the current kernel. I get a bunch of this sort of error:

    fs/compat_ioctl.c:2486: error: invalid application of ‘sizeof’ to incomplete type ‘struct dvb_frontend_parameters’

    If this is what you were trying to do, then it would seem understandable that you were having compile errors. I know this kernel source built before I copied in the new V4L driver code, as I did it just last Friday. I'll see what happens with a slightly earlier version.
    yes that was what I was trying to do. but my frame grabber have only s-video and yellow rgb don't have DVB-TV.

    kernel earlier version with RedHat 5 should work??

    Thank's for your help

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    Linux Guru Rubberman's Avatar
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    Quote Originally Posted by Lorius View Post
    yes that was what I was trying to do. but my frame grabber have only s-video and yellow rgb don't have DVB-TV.

    kernel earlier version with RedHat 5 should work??

    Thank's for your help
    Go to the LinuxTV wiki to see what they say about the kernel versions - they recommend newer kernels, such as 2.6.32 and later. RHEL 5 used the 2.6.18 kernel, so it may not work. As for your RGB inputs, it depends upon whether or not your specific device is supported by the drivers. You need to check what the device USB id codes are (manufacturer and device ids) in order to determine whether or not your actual gear will be supported, even with the latest drivers.
    Last edited by Rubberman; 02-15-2012 at 05:27 PM.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

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