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  1. Looked around and haven't found any obvious answers - hope this is the best place to post.

    I have a 1080p HDTV broadcast file (avc video, ac3 audio) that took an older 4:3 program and used non-linear stretching to expand it to 16x9 (looks normal in the middle but is stretched on the sides). I would much prefer the orignial 4:3 format - are there any tools or guides to reverse the non-linear stretching and convert the video back to the correct 4:3 (pillarbox) format?

    Any thoughts welcome : )

    bigfan5
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  2. you basically distort or "warp" it back by applying the reverse transformation ; e.g a mesh warp or bezier warp in after effects - with this you basically "stretch" or "squish" it back non linearly using a grid, or control handles

    you could try ffdshow's perspective correction, or vcmohan's reform in avisynth
    http://avisynth.org/vcmohan/Reform/Reform.html

    or xyremap (but it's not very intuitive to use unless your a "math" guy)
    http://forum.doom9.org/showthread.php?t=166087

    if you post a screenshot you might get some other suggestions
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  3. Thanks poisondeathray:

    Here are two images - Regular (from the SD broadcast) and Stretched (from the HDTV broadcast).
    Image Attached Thumbnails Click image for larger version

Name:	Regular (SD).jpg
Views:	539
Size:	32.0 KB
ID:	18228  

    Click image for larger version

Name:	Stretched (HDTV).jpg
Views:	618
Size:	40.1 KB
ID:	18229  

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  4. Try WarpedResize() part of the SimpleResize package. This looks pretty close:

    Code:
     WarpedResize(480,360, 1.1, 1.0)
    Click image for larger version

Name:	640to480.jpg
Views:	656
Size:	20.8 KB
ID:	18231

    Adjust the third argument to get closer.
    Last edited by jagabo; 4th Jun 2013 at 21:06.
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  5. Thanks jagabo!

    The uploaded pics were reduced in size, and I was thinking the original is 1080p but its actually 720p (1280x720 - snapshot attached).

    How might that change the parameters?
    Image Attached Thumbnails Click image for larger version

Name:	Original HDTV.jpg
Views:	510
Size:	110.6 KB
ID:	18233  

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  6. Wouldn't it be:

    WarpedResize(960,720, 1.1, 1.0)

    (he says, never having ruined a movie by using WarpedResize on it, or tried to undo the damage). You can add black to the sides, if you like, to bring it back to 1280x720. I'm surprised that the BBC, of all organizations, would wreck a movie like that.
    Last edited by manono; 4th Jun 2013 at 21:48.
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  7. WarpedResize() is a new one to me , thanks jagabo

    Why would the SD broadcast not have the logo ?

    Just curious , which movie is this ?
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  8. It looks like Doctor Who.
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  9. Originally Posted by manono View Post
    Wouldn't it be:

    WarpedResize(960,720, 1.1, 1.0)
    I was using his 640x360 image as the source. He can use 1440x1080 for a 1080p source. Or any 4:3 frame size he wants.
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  10. The file is a classic episode that was part of Doctor Who Revisited, The Second Doctor. The series (all 11 doctors, one a month thru November) is being aired on BBC America and I too was surprized that they'd distort the video (for some, the argument seems to be that the pillarbox black bars can ruin a plasma TV, but they then all wide screen movies are shown letterbox - go figure).
    Last edited by bigfan5; 5th Jun 2013 at 01:42.
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  11. Formerly 'vaporeon800' Brad's Avatar
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    Originally Posted by manono View Post
    I'm surprised that the BBC, of all organizations, would wreck a movie like that.
    Half-owned by Discovery.
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  12. Originally Posted by jagabo View Post
    I was using his 640x360 image as the source. He can use 1440x1080 for a 1080p source. Or any 4:3 frame size he wants.
    Sure. I was answering bigfan5 when he asked:
    Originally Posted by bigfan5 View Post
    I was thinking the original is 1080p but its actually 720p (1280x720 - snapshot attached).

    How might that change the parameters?
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  13. Originally Posted by manono View Post
    Originally Posted by jagabo View Post
    I was using his 640x360 image as the source. He can use 1440x1080 for a 1080p source. Or any 4:3 frame size he wants.
    Sure. I was answering bigfan5 when he asked:
    Originally Posted by bigfan5 View Post
    I was thinking the original is 1080p but its actually 720p (1280x720 - snapshot attached).

    How might that change the parameters?
    LOL. I totally missed that post!
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  14. Originally Posted by jagabo View Post
    LOL. I totally missed that post!
    No problem. My fault as I should have added in the quote from the post to which I was responding as I usually do.
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