8 Replies Latest reply: Oct 6, 2012 7:00 PM by Russ H
echo media Level 1 Level 1 (0 points)

I have a Standard Definition DV NTSC project that I am sending to Compressor to render files for a DVD.  The rendered m2v file shows an artifact that looks like scan lines in areas where there is a semi-transparent object such as blurred airplane propellor blades.  These scanlines are not in the original sequence images, nor do they appear when I send the sequence to Compressor and render it as a DV NTSC Quicktime.  The scanlines also appear when I render the sequence as Pro Res, or Uncompressed 10 bit.

 

Any Idea how I can get rid of them when rendering as m2v, Pro Res, or Uncompressed 10 bit?


Mac Pro, Mac OS X (10.4.8)
  • 1. Re: Scan Line artifact when rendering m2v file
    Russ H Level 6 Level 6 (14,245 points)

    It sounds like the "combing" often seen on computers when viewing interlaced video.Paly the file from a DVD player to a TV and see whether it's still present.

     

    Russ

  • 2. Re: Scan Line artifact when rendering m2v file
    David M Brewer Level 6 Level 6 (9,200 points)

    If your playing the video on a computer you need to use Frame Control in Compressor to remove the interlacing artifacts. Frame control will work for pretty much all of the codecs, ProRes, Uncompressed 10 bit, m2v, mp4 or h.264 for example.

    001.png

    First try a minute section of the video to see if this works for you.

  • 3. Re: Scan Line artifact when rendering m2v file
    echo media Level 1 Level 1 (0 points)

    David-

    Thanks but when I try to do as you suggest, the options in the Inspector window are ghosted and don't allow me to change the settings. Also- are you sure I should choose Progressive when the original footage is interlaced NTSC?

  • 4. Re: Scan Line artifact when rendering m2v file
    David M Brewer Level 6 Level 6 (9,200 points)

    Click on # 2... the 'gear' to activate Frame Control....

     

    Screen Shot 2012-10-06 at 12.45.01 PM.png

    Progressive yes!

     

    Screen Shot 2012-10-06 at 12.45.35 PM.png

    Progressive is part of the deinterlacing to remove the artifacts. If you leave this to 'Same as Source, Top First or Bottom First,' deinterlacing won't happen.

  • 5. Re: Scan Line artifact when rendering m2v file
    Russ H Level 6 Level 6 (14,245 points)

    The thing is, we can't really judge DVD quality properly on a computer screen. I'm still curious how it looks when played from a DVD Player to a TV. You may find you don't have to de-interlace at all.

     

    Russ

  • 6. Re: Scan Line artifact when rendering m2v file
    echo media Level 1 Level 1 (0 points)

    When I look at the DVD on a CRT display there are some shots that had scan lines on the computer but don't on TV.  But, as I step through it frame by frame I see strobing on each frame which makes me think that one field is blank and the next field is there.  Oddly, the propellor shots still have the scan line artifact even on the TV.

     

    I'll go back and try David's suggestion, I thought I had clicked on the gear but maybe not.

     

    I'm working on such a complex project with tons of nests within nests that it takes a full half hour just for the project to load.  It probably also doesn't help that I have HD footage included in the DV NTSC sequences- but none of those shots are giving me any problems.

  • 7. Re: Scan Line artifact when rendering m2v file
    echo media Level 1 Level 1 (0 points)

    David-

     

    Beautiful-  It worked!  Thanks so much for the help and for taking the time to make the illustrated graphics of the inspector window.  How did you learn this kind of detail?  I was thinking of taking an online course in Compressor from lydia.com- but it's a little pricey.  Any advice?

  • 8. Re: Scan Line artifact when rendering m2v file
    Russ H Level 6 Level 6 (14,245 points)

    I'm glad that it worked out for you.

     

    Thinking of others who may read this thread, stepping through interlaced footage is always going to be kind of ugly if there is any movement to speak of. The way to evaluate it is to play it.

     

    Russ