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  1. Member
    Join Date: Mar 2014
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    Hello!

    I'm a newbie here trying to learn all this stuff and I have a question about video sources that come from an NTSC DVD that are interlaced. What is the best way to make these play as progressive video?

    Does running it through Handbrake and turning the deinterlaced option on make that video progressive? Does the same go from the decombing option in Handbrake as well?

    Also, does NTSC DVDs play two kinds of FPS, correct? 23.976 FPS and 29.97? If so, which is the preferred FPS for progressive video?


    Thanks in advance!
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  2. Originally Posted by runlouierun View Post
    Also, does NTSC DVDs play two kinds of FPS, correct? 23.976 FPS and 29.97?
    No, all NTSC DVDs output interlaced 29.97fps (really 59.94 fields per second). That makes your main question unanswerable except to say, "It depends." Can you provide a short sample from the source?

    I don't use Handbrake so someone else may be able to answer the question about its use. Of course, using a deinterlacer will make a video progressive but that's often the wrong thing to do.
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  3. Member hech54's Avatar
    Join Date: Jul 2001
    Location: Yank in Europe
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    What is this obsession with something as confusing and unimportant as interlaced/progressive.....especially with newbies? Who keeps putting this crap into their heads?
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  4. I would have thought knowing whether to deinterlace or to remove pulldown, and how to do it properly, would be fairly important when re-encoding.

    https://trac.handbrake.fr/wiki/DeinterlacingGuide

    https://trac.handbrake.fr/wiki/Telecine

    If the video is purely interlaced, I'd set the output frame rate to 29.970 (constant) and enable either the de-interlace filter (slower) or decomb filter (default). Or, for smoother motion, I'd set the output to 59.940 (constant) and choose "bob" as either the de-interlacing or decomb method. The former should give you 29.970fps progressive, and the latter 59.940fps progressive.

    If the video is purely telecined, then I'd set the output frame rate to 23.976 (constant) and enable the Detelecine filter.

    https://trac.handbrake.fr/wiki/VariableFrameRate
    "The solution is to leave everything at the speed it was meant to play at. 30fps for 30fps stuff, 24fps for 24fps stuff. Leave the soft telecined parts progressive, detelecine the hard telecined parts to be progressive. When this is done within one movie file, it's called variable frame rate. The frames per second vary between 24 and 30. A place for everything, and everything in its place."

    Maybe a Handbrake user could offer some advice as to how they determine if the video is interlaced or telecined in order to deinterlace correctly. Or if the video happens to be a combination of the two, how to handle it.

    "Check the VFR box in HandBrake for Mac, or use the --vfr flag on the CLI.
    This will automatically enable the detelecine filter. It also activates the code for detelecine to drop extra frames."


    I get the impression for a mixture of interlaced and telecined, the "Handbrake method" of dealing with it would be to enable the decomb filter, select same as source and variable for the output frame rate, and you'll end up with a detelecined and deinterlaced output with a variable frame rate. I think I'd prefer to convert it all to a constant frame rate myself, but using a variable frame rate seems to be the way Handbrake prefers to do it.
    Last edited by hello_hello; 8th Apr 2014 at 20:55.
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  5. Originally Posted by runlouierun View Post

    Also, does NTSC DVDs play two kinds of FPS, correct? 23.976 FPS and 29.97? If so, which is the preferred FPS for progressive video?
    If you video is really interlace (in lots of cases it turns out it is not) and you want to make it progressive,
    -you need to bob deinterlace it to 59.94p fps. Because we are talking about SD resolution you need very good deinterlacer like QTGMC.
    -You can leave it interlace
    -if you deinterlace to 29.97p, video is kind of ruined, you can use it for web but otherwise not a good way how to treat your original
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  6. Member
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    Originally Posted by manono View Post
    Originally Posted by runlouierun View Post
    Also, does NTSC DVDs play two kinds of FPS, correct? 23.976 FPS and 29.97?
    No, all NTSC DVDs output interlaced 29.97fps (really 59.94 fields per second). That makes your main question unanswerable except to say, "It depends." Can you provide a short sample from the source?
    It's a general question so I don't have a sample right now of anything specific.

    So if NTSC DVD output 29.97, what's 23.976? HD? What's the difference between that and 24fps? Are 30fps, 24fps and 23.976 all just HD speeds?

    Are 29.97fps and 59.94 the same thing?

    You said you don't use Handbrake. What do you use instead?
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  7. Originally Posted by runlouierun View Post
    It's a general question so I don't have a sample right now of anything specific.
    Sure, but the answer to the question posed in the thread title depends on the kind of material. It might be true interlaced 29.97fps (shot on video), hard telecined film encoded as interlaced 29.97fps, film encoded as progressive 23.976fps with pulldown flags set to output interlaced 29.97fps. some interlaced PAL2NTSC garbage or a myriad other possibilities. And, in many cases, for DVD you should keep it interlaced for the reason _Al_ mentioned earlier.
    So if NTSC DVD output 29.97, what's 23.976? HD?
    As I just mentioned, for DVD film can be encoded as progressive 23.976fps with flags set to output interlaced 29.97fps. And Blu-Rays can be encoded as progressive 23.976fps without pulldown.
    Are 29.97fps and 59.94 the same thing?
    Not necessarily. As I mentioned in the previous post, the output from NTSC DVD players will be 29.97 interlaced frames per second, which is the same as 59.94 fields per second. On the other hand, 59.94 frames per second is also fairly common. For example, Blu-Rays can be 1280x720 59.94fps.
    You said you don't use Handbrake. What do you use instead?
    For making MP4s mostly for uploading to YouTube I feed AviSynth scripts into XviD4PSP or Ripbot. A lot of my material is field-blended PAL2NTSC and even if I wanted to use Handbrake (I don't), it's incapable of handling that kind of material properly.
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  8. The only constant on DVD is that the standard definition interlaced analog output is always 59.94 fields per second. The data on the DVD can be 29.97 interlaced frames per second, or any progressive frame rate from 19.98 to 29.97 frames per second with pulldown flags (the flags tell the player how to produce 59.94 fields per second from the progressive frames).

    Movies are usually shot on film at 24 frames per second. For analog transmission they are normally slowed to 23.976 frames per second and go through 3:2 pulldown to create 59.94 fields per second that you see on TV. Each film frame is thus represented by 3 or 2 fields. Other pulldown patterns are possible too. But the final analog signal always contains 59.94 fields per second -- the only thing standard definition TVs could display.

    When 59.94 field per second analog video is digitized pairs of fields are woven together to create frames at 29.97 frames per second.

    Live analog video is transmitted as 59.94 fields per second where each field represents a specific point in time. Ie, there are 59.94 unique half-pictures each second.

    When PAL video is converted to NTSC video a number of different things can be done to convert 50 fields per second or 25 frames per second to 60 fields per second, 29.97 interlaced frames per second, 25 frames per second with 3:2:3:2:2 pulldown flags, or 23.976 frames per second with 3:2 pulldown flags. Again, the constant is that the analog signal will always be 59.94 fields per second.

    Each of the above types of sources requires a specific type of handling to get the best results.
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  9. Member Cornucopia's Avatar
    Join Date: Oct 2001
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    That constant is also only constant for ANALOG output, which is getting rarer and rarer. Digital output can choose to ignore the pulldown flags of 23.976 and just send it DIRECTLY out HDMI (if the display supports it), instead of outputting 29.97.

    So the best thing to do is:
    1. Find out, from reliable methods, exactly what kind of material you are actually working with.
    2. Decide IF you need Interlaced or Progressive, and WHY.

    Then you can follow down the various paths to get from A --> E.

    Scott
    "When will the rhetorical questions end?!" - George Carlin
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  10. Video Restorer lordsmurf's Avatar
    Join Date: Jun 2003
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    Do not deinterlace for DVD.
    Do not deinterlace for DVD.
    Do not deinterlace for DVD.
    Do not deinterlace for DVD.
    Do not deinterlace for DVD.
    Do not deinterlace for DVD.
    Do not deinterlace for DVD.

    Only deinterlace for streaming sites like Vimeo or Youtube. But even then, only a second copy, not the master.
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