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  1. Hi... I have a new question for you...

    I've seen that so many movies has one of these standard:

    2.35:1 / 2.39:1 / 2.40:1.

    I've seen that probably the correct standard now is 2.39:1, but online so many conversions are either 2.35:1 or 2.40:1 for movies that on IMDB i've seen that are 2.39:1.

    Now the question is: why this and what would be the correct aspect ratio?
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  2. And there are many more:
    https://en.wikipedia.org/wiki/Aspect_ratio_(image)
    https://en.wikipedia.org/wiki/List_of_motion_picture_film_formats

    2.4:1 is a rounded figure of 2.39:1, but 2.39:1 and 2.35:1 are different and real.

    Why this? Well, technical conditions, artistic freedom and marketing aspects. There is no "correct" or "incorrect" aspect ratio, with perhaps the exception of the wrongly rounded 2.40:1 which should be 2.39:1, or correctly rounded 2.4:1
    Last edited by Sharc; 24th Mar 2023 at 17:00.
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  3. I know that there are so many aspect ratios, but my question is why so many movies listed as 2.39.1 are converted either as 2.35:1 or 2.40:1 (with 75% more inclined to 2:40:1).

    Why so many people convert files from original 2.39:1 to 2.40:1 (Please explain to me rounded), instead of using the original format that is very similar? Are there some benefits? Are there som real differences in visual aspect of the movie?

    For example, I have the same film in two different files, An original Untouched mkv that is 16:9, a ripped 1080p that is 2.40:1. In the technical parameters of IMDB, the same film has 2.39:1.
    Last edited by salvo00786; 24th Mar 2023 at 17:03.
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  4. Originally Posted by salvo00786 View Post
    Please explain to me rounded
    Basic maths: 2.39 is rounded 2.4 and NOT 2.40.
    For DVD and Blu-ray releases, studios can crop a picture as they like. Even more so illegal .mkv rips etc. It needs not to be the same as the original movie.
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  5. Ah ok, now I understood rounded, was very simple. Ok, from your explanation, I understand that is only for piracy purposes and not for real benefits...
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  6. Member Skiller's Avatar
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    For a Blu-ray of such movie, active video inside the 1080p frame is almost always 1920x800 = exactly 2.4:1.
    2:39:1 just wouldn't fit well, see: 1920÷2.39 ≈ 803.347... Would have to be rounded down to 803 which is impossible with 4:2:0 color subsampling.
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  7. Ok Skiller, thanks for the explanation.

    Now the question is, How can I convert a 16:9 movies that has black bars to 2.40:1 without adding other black bars? It's possible? Like I told you I have an untouched mkv at 16:9 and a 1080p rip at 2.40:1 (the same ripper) that have the same black bars. With MKVTOOLNIX, I have tried to change the aspect ratio to 2.40:1 of the untoched 16:9 movie and after that I converted that movie with Staxrip, but I have duplicated the thickness of the black bars.
    Last edited by salvo00786; 25th Mar 2023 at 06:36.
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  8. Member Skiller's Avatar
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    Because the letterbox is part of the encoded video, the frame is 16:9, thus setting the aspect ratio to 2.4:1 squeezes the video.

    You would have to crop the letterbox. This requires re-encoding. You don't even need to set the aspect ratio at all. Cropping by itself is sufficient.
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  9. Yes, I have to re-encode the video because I have to go from an Untouched 1080p 16:9 to a 720p 2.40:1.
    1) If I don't change the aspect ratio, the result does change automatically the aspect ratio to 2.40:1?
    2) Exist a method to estimate the exact value to crop, or I have to try?
    3) The Crop goes before or after the resize? (Ok, probably before resize, because if I crop after the redize, the new resolution would be 1280x296 instead of 1280x536).
    Last edited by salvo00786; 25th Mar 2023 at 17:19.
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  10. Member Skiller's Avatar
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    Originally Posted by salvo00786 View Post
    1) If I don't change the aspect ratio, the result does change automatically the aspect ratio to 2.40:1?
    It changes to whatever the remaining frame dimensions dictate.

    Originally Posted by salvo00786 View Post
    2) Exist a method to estimate the exact value to crop, or I have to try?
    If the source is indeed precisely 2.4:1 inside of 1080p, then the top and bottom letterbox bars will be exactly 140 lines each.

    Originally Posted by salvo00786 View Post
    3) The Crop goes before or after the resize?
    Before the resize is preferred, but after resize is also a valid way to do it, and in some cases turns out better with the numbers.

    While 2.4:1 fits very nicely into 1080p, it does not go as well with 720p:
    1280÷2.4 ≈ 533.333


    If I was you I would crop first (1920x800) and then resize that to 1280x532, accepting an error of 1⅓ lines.
    Last edited by Skiller; 25th Mar 2023 at 22:21.
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  11. Originally Posted by salvo00786 View Post
    Yes, I have to re-encode the video because I have to go from an Untouched 1080p 16:9 to a 720p 2.40:1.
    1) If I don't change the aspect ratio, the result does change automatically the aspect ratio to 2.40:1?
    2) Exist a method to estimate the exact value to crop, or I have to try?
    3) The Crop goes before or after the resize? (Ok, probably before resize, because if I crop after the resize, the new resolution would be 1280x296 instead of 1280x536).
    1) The output (assuming you're cropping the black) should have the same aspect ratio as the remaining picture after cropping, so it depends how much you crop.
    2) Doesn't Staxrip do that for you (automatically resize to maintain the correct aspect ratio)? Most GUIs let you pick a width, and after any cropping, resize the height accordingly, or something similar.
    3) After you've resized, there won't be as much black to crop. 140 pixel borders at 1080p might only be 90 pixel borders after resizing to 720p.

    The formula for calculating resizing is fairly simple for non-anamorphic video. After you've cropped any black, it's
    Cropped Source Height / Cropped Source Width × New Width = New Height

    or without cropping
    Source Height / Source Width × New Width = New Height

    Making up cropping to use as an example and resizing to a width of 1280.

    Crop(2, 140, -6, -142)
    Spline36Resize(1280, 536)

    798 / 1912 ×1280 = 532 or 536 (whichever way you round from 534.22).

    You could also give CropResize a test drive. Unlike "normal" resizing it won't stretch the picture. If the source aspect ratio and the output aspect ratio (resizing) don't match, it'll crop some extra picture to prevent aspect error. Until you get used to it, it's generally better to only specify an output width or height (not both) and the script will take care of the other. CropResize also applies your desired cropping so there's no need to use Crop(). The following would output 1280x536 without having to round, because the cropping is exact (it uses the resizer to apply sub-pixel cropping if necessary).

    Preview:
    CropResize(1280,0, 2,140,-6,-142, CPreview=1, Info=true)

    Image
    [Attachment 69980 - Click to enlarge]


    CropResize(1280,0, 2,140,-6,-142)

    Image
    [Attachment 69981 - Click to enlarge]
    Last edited by hello_hello; 25th Mar 2023 at 22:30.
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  12. Originally Posted by salvo00786 View Post
    Yes, I have to re-encode the video because I have to go from an Untouched 1080p 16:9 to a 720p 2.40:1.
    1) If I don't change the aspect ratio, the result does change automatically the aspect ratio to 2.40:1?
    2) Exist a method to estimate the exact value to crop, or I have to try?
    3) The Crop goes before or after the resize? (Ok, probably before resize, because if I crop after the redize, the new resolution would be 1280x296 instead of 1280x536).
    I would suggest to keep it simple and resize the 1920x1080p including the borders to 1280x720p, including the borders, and be done with it. Your TV (or monitor) is probably not 2.4:1 but rather 16:9 or similar, hence the frame will have to be rescaled/letterboxed/pillarboxed for playback anyway accordingly.
    Last edited by Sharc; 26th Mar 2023 at 03:18.
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  13. Ok, thanks for all your replies, I will Try.
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