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  1. I am trying to convert a video to Apple TV. I want to crop off the overscan, but throughout the show (~20 min), the left border has different black overscan width depending on the scene. How do I keep the show centered as made for presentation while cropping off the extra properly?
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    Join Date: Jun 2012
    Location: USA
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    Please post a short sample of a segment where the change occurs.
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  3. Use AviSynth's Trim command (followed by a resize) to crop different sections differently?
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  4. Super Mario Bros Super Show

    The nature of the show being part cartoon/part live-action, the video was not the same width. I just want to get an idea on how to I should be cropping the file.

    I initially cropped 16 off the left to get the overscan and frame sync stripe off, and 4 for the black bar on the right. Looks OK but want to make sure I am doing it correctly. I searched for a similar topic for a while but I don't know that anyone else has brought this up or nitpicks as much as I do.

    http://tinypic.com/r/2iag954/8
    http://tinypic.com/r/2959yq8/8
    http://tinypic.com/r/29uzgxh/8
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  5. Originally Posted by manono View Post
    Use AviSynth's Trim command (followed by a resize) to crop different sections differently?
    My goal is to bring the DVDs into iTunes, so an episode-by-episode edit would be best but isn't practical at the moment. I have other shows I am planning on converting and I'm hoping the help you guys can give me will guide me on how to handle those as well.
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  6. My logic is this.... the DVD should be designed to allow for over-scanning.... normally you won't see the crud, but in many cases you also won't see a little of the picture..... so my logic tends to be to find the frame with the most about of black, crop it completely, and if it means some sections of video have a little picture cropped as well as the black, so be it. You wouldn't normally see it anyway.

    Having said that.... I have encoded episodic DVDs where the amount of black various by a large amount (ie from 8 pixels to 36 pixels in places), even within a single episode. Sometimes that puts my brain into OCD mode and I start cropping scenes differently so as not to remove large chunks of picture.

    I've never used iTunes. Can it convert video? If you want to apply different cropping for each episode, but the same amount from start to finish.... most conversion programs have an auto crop function which usually does a good job, but usually also requires a human to preview and fine tune it if you want it perfect. Cropping and resizing using MeGUI looks something like this, but most conversion programs do it in a similar manner. Most will auto crop but if you want perfection, and if you want to crop to output a nice 4:3 aspect ratio without distorting the picture, it pays to fine tune it manually, or crop enough each time so the crud is always removed, even if sometimes so is some of the picture.

    Click image for larger version

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  7. Originally Posted by hello_hello View Post
    My logic is this.... the DVD should be designed to allow for over-scanning.... normally you won't see the crud, but in many cases you also won't see a little of the picture..... so my logic tends to be to find the frame with the most about of black, crop it completely, and if it means some sections of video have a little picture cropped as well as the black, so be it. You wouldn't normally see it anyway.

    Having said that.... I have encoded episodic DVDs where the amount of black various by a large amount (ie from 8 pixels to 36 pixels in places), even within a single episode. Sometimes that puts my brain into OCD mode and I start cropping scenes differently so as not to remove large chunks of picture.

    I've never used iTunes. Can it convert video? If you want to apply different cropping for each episode, but the same amount from start to finish.... most conversion programs have an auto crop function which usually does a good job, but usually also requires a human to preview and fine tune it if you want it perfect. Cropping and resizing using MeGUI looks something like this, but most conversion programs do it in a similar manner. Most will auto crop but if you want perfection, and if you want to crop to output a nice 4:3 aspect ratio without distorting the picture, it pays to fine tune it manually, or crop enough each time so the crud is always removed, even if sometimes so is some of the picture.

    Attachment 26285
    Thank you for your response. I can certainly try out MeGui; I have been using vidcoder/handbrake but they do similar things. I can crop unevenly on both sides, but my question was more focused on "is it better to crop the same amount from each side to keep video centered but lose some image, or is it better to crop only as needed and lose the video being centered.
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  8. Originally Posted by premiumcapture View Post
    is it better to crop the same amount from each side to keep video centered but lose some image
    No.

    Originally Posted by premiumcapture View Post
    or is it better to crop only as needed and lose the video being centered.
    If you didn't have access to the video with the black borders you would never even know the picture was slightly off center. And in fact, your source video is already off center. By cropping unevenly you are restoring the centering.
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  9. Originally Posted by premiumcapture View Post
    or is it better to crop only as needed and lose the video being centered.
    If you didn't have access to the video with the black borders you would never even know the picture was slightly off center. And in fact, your source video is already off center. By cropping unevenly you are restoring the centering.[/QUOTE]

    Forgive me for being a novice, but even though it is uneven, isn't one of the purposes of overscan to center? I only bring this up because I am looking at the following image:

    http://tinypic.com/r/qretnd/8

    If I crop unevenly, I believe Mario's head will fall out of center, which I checked with test crops in VirtualDub to count pixels into the center. Am I wrong here?
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  10. There's really no cropping rules. Using your pic as an example I'd possibly be tempted to crop the same each side and keep the image in the middle, but it depends what the rest of it's like. Very often a DVD will seem to require more cropping on one side than the other, but in places it'll switch sides, so unless you want to adjust the cropping throughout you end up having to crop the same amount each side anyway. It pays to manually check the whole thing as thoroughly as you can, but if in doubt, I'd probably play it safe and crop each side the same.

    The image in the middle..... that's possibly more an exception than the rule. I've encoded lots of episodic DVDs where, for example, an image in the opening credits is dead centre, next episode it's off to one side a bit but cropping just what's necessary doesn't put it back in the middle.... so just do whatever works for you.
    Last edited by hello_hello; 10th Jul 2014 at 05:14. Reason: spelling
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  11. Originally Posted by premiumcapture View Post
    Forgive me for being a novice, but even though it is uneven, isn't one of the purposes of overscan to center? I only bring this up because I am looking at the following image:

    http://tinypic.com/r/qretnd/8
    I'll grant you that particular image is off center if you crop away the black borders, but I think that's the exception, not the rule.

    First your use of the term overcscan is isn't quite accurate. CRT based TVs were not good at centering the picture, keeping it nice and rectangular, perfectly horizontal, etc. And all those problems would change with time and temperature. So CRT televisions
    Code:
    overscanned
    -- they only showed the center portion of the picture. The outer edges were hidden behind the bezel, about 5 percent at each edge. That made the geometric distortions less obvious. If the TV drifted off to the side a little, or if the picture suffered from pincushion or barrel distortions, or was slightly slanted, you weren't likely to see a black border or notice the picture wasn't geometrically perfect.

    Modern television technology doesn't have those problems but sets continue to simulate overscan in case there's garbage at the edges of the frame. Ie, broadcasters know you can't see the very edges of the frame so they don't care if there's garbage out there. So TV manufactures have to continue cutting off the edges of the picture to keep people from thinking there was something wrong with their TV. Most modern TVs overscan by 2 or 3 percent at each edge of the frame. And some TV's have an option not to overscan at all.

    I'm going to skip a lot of details here but... when standard definition analog video is digitized the 4:3 picture is contained in a ~704x480 or 704x576 frame. It's customary to capture a slightly wider frame, 720 pixels, in case the analog signal is slightly off center. That prevents part of the real picture from being lost. That is what you are seeing here. With TVs that overscan you would not see those black borders, even if the picture was shifted fully to one side of the 720 pixel wide frame (ie, no black border on one side, 16 pixels worth at the other). So generally, if the black borders aren't equal it's because the analog picture was off center.
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  12. Originally Posted by jagabo View Post
    I'm going to skip a lot of details here but... when standard definition analog video is digitized the 4:3 picture is contained in a ~704x480 or 704x576 frame. It's customary to capture a slightly wider frame, 720 pixels, in case the analog signal is slightly off center. That prevents part of the real picture from being lost. That is what you are seeing here. With TVs that overscan you would not see those black borders, even if the picture was shifted fully to one side of the 720 pixel wide frame (ie, no black border on one side, 16 pixels worth at the other). So generally, if the black borders aren't equal it's because the analog picture was off center.
    Just to clarify, but the D1 video you are talking about would or would not contain black bars (704+16 or 698+~6 for example)? And also, you are saying that TV's have the ability to read the borders and center the image themselves?
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  13. Originally Posted by premiumcapture View Post
    Just to clarify, but the D1 video you are talking about would or would not contain black bars (704+16 or 698+~6 for example)?
    The full 720 pixel wide frame contains black bars (or whatever was in the original signal).

    Originally Posted by premiumcapture View Post
    And also, you are saying that TV's have the ability to read the borders and center the image themselves?
    No, TV's do not center the image. They just display what they're given. The padding in the D1 frame is there for the studio/broadcaster. They might choose to recenter the video.
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