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  1. Member brassplyer's Avatar
    Join Date: Apr 2008
    Location: United States
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    I have a VHS DV capture I'm saving as Huffyuv, then cleaning with NeatVideo and converting to DVD mpeg.

    How would you crop the switching noise off the bottom to ensure the spatial relationship of the interlacing is maintained, the original proportion of the video is maintained and not introduce any artifacts?
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  2. You could just cover it with black using a Letterbox command. For example:

    Letterbox(0,12)

    Otherwise bob, crop, resize, reinterlace.

    If there's stuff below the garbage lines worth saving, you could try jagabo's InterpolateScanLines function.
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  3. Member
    Join Date: Feb 2008
    Location: United States
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    Make sure to crop with an even number to preserve the field order. Then restore the original dimensions using AddBorders, be sure not to resize the interlaced videos. Again, AddBorders should not contain any odd numbers.

    Crop(x,x,x,x)
    AddBorders(x,x,x,x)
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  4. For interlaced YV12 video you should crop/addborders mod4 on the vertical axis or you'll get blurring of the chroma.
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  5. Banned
    Join Date: Oct 2004
    Location: New York, US
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    -30-
    Last edited by sanlyn; 19th Mar 2014 at 10:08.
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  6. Add the letterboxing to the top and bottom evenly, don't just replace the bottom with a black bar on the bottom.
    If you want to see what I've done with my videos,
    check out my video work on youtube, http://www.youtube.com/user/duhmez/
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  7. Originally Posted by duhmez View Post
    Add the letterboxing to the top and bottom evenly, don't just replace the bottom with a black bar on the bottom.
    That may be best cosmetically, but it may not be best in terms of encoding efficiency or encoding artifacts. MPEG family codecs work best when borders fall on mod8 boundaries (because they work with 8x8 DCT blocks).
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  8. Originally Posted by jagabo View Post
    Originally Posted by duhmez View Post
    Add the letterboxing to the top and bottom evenly, don't just replace the bottom with a black bar on the bottom.
    That may be best cosmetically, but it may not be best in terms of encoding efficiency or encoding artifacts. MPEG family codecs work best when borders fall on mod8 boundaries (because they work with 8x8 DCT blocks).
    Interesting, I had not thought of that. So if for example homie needed to remove exactly 8 lines, you say the encode quality would be best to do addborders(0,0,0,8) at the end.
    If you want to see what I've done with my videos,
    check out my video work on youtube, http://www.youtube.com/user/duhmez/
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  9. I've experimented with borders of different widths/heights in order to see how much difference it makes, and in respect to compressibility it's too little to think about. I've read threads where people have asked about the picture being blurred a little at the edges (just a couple of rows of pixels) when borders are used, which I'd assume would be a mod8, or maybe even a mod16 thing. I rarely use borders so I haven't really noticed it happening myself.
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