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  1. Member
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    I have a 1080i video I am converting to 720p. It has a 25.0 fps framerate, which I don't completely understand, because I thought 25 FPS was a PAL thing, and there is no more PAL/NTSC distinction at HDTV resolutions?

    But anyway, on first conversion attempt, I checked "Framerate (FPS): same as source" in Handbrake, but the resulting video is 50 FPS. I am not familiar with 50 FPS. Why did it convert to that resolution? Should I change it to 23.976 or 29.97?
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  2. You made it 720p so it was made 50fps (I would guess) because 720p for Blu-Ray has to be 50fps. That 720p video, is every frame different or is every unique frame followed by a duplicate?

    If you read What Is Blu-Ray you'll see 25i for 1080 and 50p for 720 are perfectly okay.
    Last edited by manono; 25th Jan 2015 at 19:22.
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    Originally Posted by Knocks View Post
    there is no more PAL/NTSC distinction at HDTV resolutions?
    Would be a smart move wouldn't it?

    However stuffy old engineers put a stop to that idea!

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  4. Member Skiller's Avatar
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    Originally Posted by newpball View Post
    Would be a smart move wouldn't it?

    However stuffy old engineers put a stop to that idea!
    Oh, please stop trolling around, it's getting old.



    Originally Posted by Knocks View Post
    because I thought 25 FPS was a PAL thing, and there is no more PAL/NTSC distinction at HDTV resolutions?
    Well, PAL and NTSC are actually just analog color modulation techniques, so from that point of view, yes, there is no PAL/NTSC with HD. The video dimensions in pixels are always the same in HD (either 720p or 1080i/p) but the field rates and frame rates of PAL and NTSC terretories were kept to provide backwards compatibility.



    Originally Posted by Knocks View Post
    but the resulting video is 50 FPS. I am not familiar with 50 FPS. Why did it convert to that resolution?
    Because that's the field rate of a 25 fps interlaced video. 25 interlaced frames contain 50 fields which, after bob-deinterlacing, turn into 50 frames.


    Originally Posted by Knocks View Post
    Should I change it to 23.976 or 29.97?
    No, that would be catastrophic to watch.
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    Skiller, thank you for a comprehensive answer.
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  6. Originally Posted by newpball View Post
    Originally Posted by Knocks View Post
    there is no more PAL/NTSC distinction at HDTV resolutions?
    Would be a smart move wouldn't it?

    However stuffy old engineers put a stop to that idea!

    It's not a PAL/NTSC distinction but a framerate distinction. There's plenty of native 25fps content. You'd ban all that, then?
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    Originally Posted by Skiller View Post
    Well, PAL and NTSC are actually just analog color modulation techniques, so from that point of view, yes, there is no PAL/NTSC with HD. The video dimensions in pixels are always the same in HD (either 720p or 1080i/p) but the field rates and frame rates of PAL and NTSC terretories were kept to provide backwards compatibility.
    That is great news, so all devices that comply with the high definition standard can play 720/25p, 720/30p, 1080/25i and 1080/30i (and optionally 1080/25p and 1080/30p).

    Wonderful!

    I stand corrected!
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  8. Member Cornucopia's Avatar
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    @newpball, it's not the "stuffy old engineers" that killed the idea of a common format, it was their bosses - the stuffier managers & CEOs of entertainment companies. And they did it because of pressure from the even stuffier Politicians who mandated certain national standards. Funniest part is: they did that at the behest (and representation of) the stuffiest of all - the public. That means YOU (and me).

    Now, you want to change things to be all just common, but there is NO consensus as to what that common thing ought to be. Why? Because different people have different needs for their media and there are still actual, real, physical & economic limits on what can be done and how. Until people have instant free easy infinite bandwidth & instant free easy infinite storage capacity throughout the creation-production-distribution chain, there will ALWAYS BE variations, or there will be certain populations that are being badly served and/or disappointed by their media (when they are given media that is not native/optimal to their needs), because of variations being taken away from them (and they are on the "losing side"). And who would agree to be on the "losing side"?

    You sound just like those linguists who, in their zeal to create the "common, universal language", came up with Esparanto: Just one MORE separate confusing & complicated language that never got much traction from anyone because it was driven by people who didn't fully understand the nature & dynamics of the problem of multiple languages & cultures.

    Scott
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    Wow, this is being taken massively off topic. All I wanted to know was why a 25 FPS interlaced video became 50 FPS progressive and whether I should change it to another framerate, and those questions were answered. Thanks.
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  10. Originally Posted by Knocks View Post
    All I wanted to know was why a 25 FPS interlaced video became 50 FPS progressive and whether I should change it to another framerate, and those questions were answered. Thanks.
    Just because a video is encoded as 25i doesn't mean there are 50 different pictures per second. Most film based material will have pairs of fields from the same film frame and should be converted to 25p. Live sports and news are likely to be true interlaced video and should be converted to 50p (unless you have playback limitations). The there are NTSC/PAL conversions with field blending where things get much more complex.
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    Yes, but the point is that I told Handbrake to keep the framerate the same as source, and it still converted it from 25 to 50fps. Which makes the explanation that there were in fact 50 different frames per second plausible.
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  12. Originally Posted by Knocks View Post
    Yes, but the point is that I told Handbrake to keep the framerate the same as source, and it still converted it from 25 to 50fps. Which makes the explanation that there were in fact 50 different frames per second plausible.
    Unlikely, if this was the same animated feature you mentioned in the other thread.

    Very likely it originated as "24p" (perhaps even with duplicates to begin with), and it underwent a standards conversion to 50 fields per second to be broadcast in a 50Hz area

    99.99999999999999999999999999999998% unlikely that it had 50 unique frames per second as the original source, or 50 unique fields per second as the broadcasted version.

    You probably now have have 50 frames of blended and duplicate frames per second. You can verify this for yourself, just open it up in a media player, or editor, and go frame by frame . Ideally, most people would want to return it to the original "24p" rate
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  13. Originally Posted by Knocks View Post
    Yes, but the point is that I told Handbrake to keep the framerate the same as source, and it still converted it from 25 to 50fps.
    Unless the program has changed recently, when you tell Handbrake to keep the same frame rate as the source, 25i is converted to 25p. And 30i is converted to 30p.
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