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  1. Hello everyone.

    So, I've capturing VHS using Mencoder for a long time, and sometimes the videos get captured (for brief moments) with the red saturation maxed out. I'm also posting a video sample so you can see what I'm talking about. In this case it's for a few seconds, but sometimes it can last for minutes until it gets normal.

    https://youtu.be/-TwvYaBqcs4

    It usually happens with tapes that were recorded from the TV, or tapes copied from VCR to VCR, and there's some sudden stop in the recording, and re-recording. Like, when a show went to commercial break, the person would stop the recording, and then record again after the break.

    Another thing I should mention is that, if this red saturation issue goes for long, I can correct it by pausing the tape, watching when the colors are corrected, and then pressing play. It also works when I unplug the video cable from the VCR, and plug it back. That usually fixes the problem.

    This is the command I use to capture:

    Code:
    mencoder tv:// -tv driver=v4l2:norm=PAL-Nc:width=720:height=576:input=1:fps=25:amode=1:audiorate=48000:forceaudio:immediatemode=0 -oac pcm -ovc xvid -xvidencopts pass=1 -o FILE
    My capture device is a Kword PVR-TV 7134SE PCI card.

    Same thing happens with MPlayer, though it's basically the same software as Mplayer.

    Thanks in advance for the videohelp.

    Regards.
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  2. Mountains of gear vaporeon800's Avatar
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    On Windows XP you could try disabling the (chroma) AGC of the SAA713x chip. It's probably possible on Linux, but I don't know how.
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  3. I'm going to try that on Windows 7. I don't remember right now if I had the same issue under Windows. I don't normally use Windows, I have never used it to capture video.
    How do you disable AGC on Windows 7 (I don't have XP)? Do you do it on the software the capture card comes with? Or tweaking something in the control panel?

    Thank you.
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  4. Member godai's Avatar
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    curious what kind of tapes you have, i collect soccer games.

    a good vcr can helps in that situation
    also kworld its not best, ati tv wonder 600 usb or colossus give good results.
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  5. I haven't used the Philips/NXP-based SAA713x PCI cards, but for the conexant-chip based ones and usb dongles QV4L2 lets you adjust a bunch of stuff. It's readily available for most linux distros. If you want to go really low-level it's also possible to communicate directly with the SAA chip over i2c using a command-line i2c program (if you can find the datasheet with adresses) but that can be a bit clunky.
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  6. Mountains of gear vaporeon800's Avatar
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    Originally Posted by the98 View Post
    How do you disable AGC on Windows 7 (I don't have XP)?
    I don't think you can. I did it using FLY 2000 TV with its specialized driver access and DScaler with its in-built driver.
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  7. Originally Posted by oln View Post
    I haven't used the Philips/NXP-based SAA713x PCI cards, but for the conexant-chip based ones and usb dongles QV4L2 lets you adjust a bunch of stuff. It's readily available for most linux distros. If you want to go really low-level it's also possible to communicate directly with the SAA chip over i2c using a command-line i2c program (if you can find the datasheet with adresses) but that can be a bit clunky.
    Image
    [Attachment 51329 - Click to enlarge]


    I have been playing with QV4L2, but I have had no luck. What parameters do you think I should tweak to see if this issue goes away?

    Thank you.
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  8. It would be under "user controls" if there's a setting for it.
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  9. Video Restorer lordsmurf's Avatar
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    I've capturing VHS using Mencoder
    Why?
    VirtualDub is more ideal. So, again, why?

    The underlying issue, as always, is probably lack of TBC.
    What does your hardware workflow chain look like? (VCR, TBC, capture card, brand/model of each)
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  10. Originally Posted by oln View Post
    It would be under "user controls" if there's a setting for it.
    Nothing relevant in that tab

    Originally Posted by lordsmurf View Post
    I've capturing VHS using Mencoder
    Why?
    VirtualDub is more ideal. So, again, why?
    I don't use Windows, so VirtualDub is not an option. Although I have recently installed Windows 7, for games and other tests, I don't normally use that OS.
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  11. I can't find the register definition for these chips anywhere, so I don't know what register you would have to poke to turn the AGC off. That said, it's possible there could be something wrong with the card itself. Does the same happen from a video source that is not a tape?
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