VideoHelp Forum




+ Reply to Thread
Results 1 to 9 of 9
  1. I have been having a problem when converting. In the dark scenes of the episode, those objects in low light turn a reddish hue. This is really noticable on people. I was wondering if anyone had any ideas on how I might fix this problem.

    I am using an osprey 200 to capture, using Virtual dub with the mjpeg codec (18 quality). Then I use TMPG Encoder with the NTSC SVCD template to encode. The odd thing is when I play the video back on my monitor, before encoding, the shadows aren't so dark and the color doesn't look distorted.
    This leads me to think it may be the encoder.

    Any help would be appriciated.
    Quote Quote  
  2. Member vhelp's Avatar
    Join Date
    Mar 2001
    Location
    New York
    Search Comp PM
    rogue003,

    I think this has to do w/ the color
    space issue. the MJPEG codec, be
    it hardware or software utilizes
    a different color space. Why? I
    dont know!! But, in my experience,
    there's no alternative but to
    live with it. some people get so
    use to it, they forget there was
    even a problem with the color.

    You could play around with the col
    or settings in tmpg to see it you
    can correct the color space issue.
    I remember reading something up
    on the MJPEG color space issue,
    but I can't remember where, and I
    believe they had a somewhat vauge
    answer to solve it.

    If you really want to see these
    BAD color space issues, try and
    capture "Star Trek Enterprise"
    YOU WILL see how bad the color
    space issue is for sure.

    -vhelp
    Quote Quote  
  3. Typically, capture codecs operate in the YUV2 colorspace, whereas TMPGEnc operates in the RGB colorspace. There are several possible, albeit imperfect solutions:

    1. Run your capture codec in RGB mode, this will probably require a lot of hard drive space for the capture
    2. Try doing the colorspace conversion with a tool that might use more intelligent algorithms for it, such as Avisynth
    3. Use the color adjustment filter in TMPGEnc to attempt to reduce or correct the effects of the conversion
    4. Use CCE, which can encode video in YUV2 without a colorspace conversion
    Quote Quote  
  4. Member vhelp's Avatar
    Join Date
    Mar 2001
    Location
    New York
    Search Comp PM
    kinneera,

    I was really gearing for the DC10+
    cards captures, since its based on
    the MJPEG codec or what-not.

    You CANT adjust the color space for
    the DC10 card though. It's set in
    hardware or something, and the conf
    in studio or even if I use AVI_IO
    have no effect on it. The only
    way to ajust colors for DC10+ capt
    ures is to do it in the AVI file
    after captutes.

    -vhelp
    Quote Quote  
  5. Is the osprey 200 based on the same chip as the DC10+ ? If not, that suggestion might still be useful to the original poster. In any case, I believe you if you say you can't change the colorspace at capture with your card. Still might be worth a shot to try some of the other solutions, though.
    Quote Quote  
  6. Member vhelp's Avatar
    Join Date
    Mar 2001
    Location
    New York
    Search Comp PM
    kinneera and orig. poster,

    sorry, didn't mean to sound like
    I was trying to sway you away from
    any advise.

    -vhelp
    Quote Quote  
  7. Thanks for the advice. How would I encode in RGB using the mjpeg codec?

    And where might I find the Avisynth tool, I don't see it on the tools page.

    And as far as the chip on the osprey. The main chip is labelled:
    Conexant. Vdub lets me adjust the Brightness, Contrast, Saturation, & Hue. I don't know where to look to find any other color settings.
    Quote Quote  
  8. Member vhelp's Avatar
    Join Date
    Mar 2001
    Location
    New York
    Search Comp PM
    This is where I got my version of AVIsynth:
    -------------------------------------------

    * Here is a website on AVIsynth:
    * Here are some other D/L's stuff for you to digest:
    * AVIsynth Beta 5 download

    There. I hope I have ben helpful this time around

    Kinneera,
    As far as how to "match" the color
    space to other video files, I'd
    sure love to know how to do this.
    ie, in one movie the colors are
    shifted somehow and shows washed
    out colors into a richer looking
    set of colors, and I'm not talking
    about adj Hue or contrast.
    I'm talking about "shifing" the
    whole color spectrum. If you need
    me to be more clear, I have a clip
    for ya to D/L (two that is) and
    both are from a DVD, but one is
    richer in color, while the other's
    color, is washed out, though still
    nice. let me know if you want more
    details. As, I'm still searching
    for this golden recipe on color
    space shifting ...or whatever you
    call it.

    -vhelp
    Quote Quote  
  9. I think the main effect of mismatched colorspaces occurs in the luminence channel, but I am by no means an expert on this. I'm more just aware that the problem exists. In CCE, for example, there is an option that allows you to choose a color range that looks something like 24-252 and one that is from 0-255. The 0 to 255 is RGB, the other is YUV2. Keep in mind that computer monitors are RGB devices, so even if video looks washed out on your computer screen, it may be fine on a TV.
    Quote Quote  



Similar Threads

Visit our sponsor! Try DVDFab and backup Blu-rays!