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  • Duplicated frames, jerky motion

  • Zach Worden

    August 3, 2015 at 1:37 pm

    I have some HDV footage that was shot at a slow shutter speed in low light. In a 60i project, every frame repeats once. It needs to end up in a 24p project, but when I bring it into that project there is no pattern to the repeated frames and the motion is really jerky. Any ideas on potential fixes would be greatly appreciated.

    Zach

  • Michael Phillips

    August 3, 2015 at 5:43 pm

    Can it be slow motion, or does it have to be “at speed”?

    Michael

  • Zach Worden

    August 3, 2015 at 5:48 pm

    Some of the shots could be slowed down a little bit.

    Zach

  • Michael Phillips

    August 3, 2015 at 7:07 pm

    I am assuming it was shot interlace? So there are 59.94 fields of motion every second? Or was it shot progressive at either 29.97p or 59.94p. This changes the way one might approach the problem. At the end of the say, it will either be a frame for frame slomo – which means no artifacts but everything is slower, or frame rate manipulation to create 23.976 progressive frames from 59.94 fields or frames.

    Michael

  • Zach Worden

    August 3, 2015 at 7:10 pm

    I’m pretty sure it was shot interlaced.

    Zach

  • Michael Phillips

    August 3, 2015 at 9:41 pm

    OK – you have a lot of issues fighting you for quality here.

    1. Slow shutter creates more movement within the field/frame that a faster/higher shutter speed
    2. Interlace also has motion in one half the frame (odd lines) and different motion in the second half the frame (even fields)
    3. With interlace, you have one set of motion that is half the horizontal resolution of the format being shot. For example an interlace frame of 1080 HD is actually made up of two fields of 1920×540.

    This is where hardware-based convertors earn their reputation for higher quality as they do a lot of motion estimation and such when doing conversions.

    You can get pretty good quality with software conversions – Twixtor has a good reputation and can be used as a free trial (watermarked).

    You can try different motion adapters in Media Composer for different quality, but due to the above 3 bullet points it will not be great.

    If you can get away with slomo (20%), then you can deinterlace, have 29.97p frames, then play that back as 23.976 frame for frame.

    Michael

  • Shane Ross

    August 3, 2015 at 10:12 pm

    What camera? Because early SOny HDV cameras had a “cine mode” that was horrid. It faked the film look by shooting 30fps…interlaced…but repeated frames. So it was 15fps, with duplicated frames. HORRBLE, I say.

    Sounds like that’s what’s happening here.

    Shane
    Little Frog Post
    Read my blog, Little Frog in High Def

  • Robert Ober

    August 3, 2015 at 10:42 pm

    [Zach Worden] “I’m pretty sure it was shot interlaced.”

    Drag a clip to Mediainfo and see what it says.

    Robert

  • Zach Worden

    August 4, 2015 at 3:29 pm

    Thanks. Here’s what I got from Mediainfo:

    Zach

  • Michael Phillips

    August 4, 2015 at 3:32 pm

    Interesting frame size – if you are willing to send me a sample, I will take a look at it in Media Composer and try some different frame rate conversions for you. use wetransfer.com or filemail.com to send to: michael[at]24p[dot]com

    Michael

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