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  1. Member
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    So I have a DVD (of a US TV show shot originally on film) which my Blu-ray player switches to 24p mode when playing, which leads me to believe it's using pulldown flags, which eac3to says is true:
    Code:
    1: MPEG2, 480p24 /1.001 (4:3) with pulldown flags
    2: AC3 Surround, 2.0 channels, 192kbps, 48kHz, dialnorm: -27dB, 19ms
    3: Subtitle (SRT)
    Which sounds fine to me.

    Also when I open the file in VideoRedo, certain frames are marked as "psuedo" frames (leaving a total of 24 "real" ones per second), which also makes sense.

    However FFmpeg etc. tells me that the VOB file in question is actually at 29.75fps, which is baffling me somewhat (I guess FFMpeg doesn't check for the pulldown flags to determine the "true" fps)

    But anyway, my goal is to take that file, remove the pulldown flags and therefore I should be left with a 24p file, containing only the "real" frames. Can I do that without re-encoding? Or have I mis-understood what pulldown flags do?

    I was under the impression that the file on disc would actually be at 24fps, and the pulldown flags just said "repeat this frame" a few times in order to bring it up to 30.
    Last edited by bergqvistjl; 6th Jul 2019 at 12:47.
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  2. Originally Posted by bergqvistjl View Post
    I was under the impression that the file on disc would actually be at 24fps, and the pulldown flags just said "repeat this frame" a few times in order to bring it up to 30.
    That's not exactly right, but the true framerate is really 29.97fps as required for NTSC DVDs. If it's 100% soft pulldown it was encoded as progressive 23.976fps with the pulldown flags (the TFF and RFF flags) added so it outputs 29.97fps.

    To get it back to true progressive 23.976fps and strip out the pulldown flags:

    1. Demux audio and video (DGIndex with File->Save Project and Demux Video)
    2. Add the M2V to DGPulldown with the "Custom" box ticked and 23.976->23.976.
    3. Remux audio and new M2V using ImagoMPEG-Muxer.

    No reencoding.
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  3. Member
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    Originally Posted by manono View Post
    Originally Posted by bergqvistjl View Post
    I was under the impression that the file on disc would actually be at 24fps, and the pulldown flags just said "repeat this frame" a few times in order to bring it up to 30.
    That's not exactly right, but the true framerate is really 29.97fps as required for NTSC DVDs. If it's 100% soft pulldown it was encoded as progressive 23.976fps with the pulldown flags (the TFF and RFF flags) added so it outputs 29.97fps.

    To get it back to true progressive 23.976fps and strip out the pulldown flags:

    1. Demux audio and video (DGIndex with File->Save Project and Demux Video)
    2. Add the M2V to DGPulldown with the "Custom" box ticked and 23.976->23.976.
    3. Remux audio and new M2V using ImagoMPEG-Muxer.

    No reencoding.
    That works fine thanks! Also it turns out I can literally stick the original VOB file into TSMuxer, click "remove pulldown" on the video track, set the framerate to 24/1001 and it gives me back the exact same output (after muxing) as doing it with dgmpgdec & dgpulldown.

    My next step is doing the same but with episodes that were shot the same way, but encoded on disc with no pulldown... Although I'm sure that will require re-encoding.
    Last edited by bergqvistjl; 7th Jul 2019 at 05:54.
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  4. Originally Posted by bergqvistjl View Post
    Also it turns out I can literally stick the original VOB file into TSMuxer, click "remove pulldown" on the video track, set the framerate to 24/1001 and it gives me back the exact same output (after muxing) as doing it with dgmpgdec & dgpulldown.
    I also remove pulldown from time to time and didn't know that. Thanks for the tip. Sounds faster. I assume it spits out an MPG and not a VOB? Because VOBs aren't supposed to be 23.976fps.
    My next step is doing the same but with episodes that were shot the same way, but encoded on disc with no pulldown... Although I'm sure that will require re-encoding.
    If hard telecined (make a D2V project file using DGIndex, open it and it'll say 100% VIDEO at the very bottom), then yes, a full reencode with an IVTC applied will be necessary.
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  5. Beware that VOB often has mixed content (30i and 24p with pulldown, other p with pulldown) so you may lose A/V sync when stripping pulldown flags.
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  6. Originally Posted by jagabo View Post
    Beware that VOB often has mixed content (30i and 24p with pulldown, other p with pulldown) so you may lose A/V sync when stripping pulldown flags.
    Right, which is why I began my own suggestion with, "If it's 100% soft pulldown..."

    The D2V will tell you with 100% FILM at the bottom. I've only done it with my own DVDs which I already know are 100% film. I can't speak for bergqvistjl and his sources, of course, but he seems to know what he's doing.

    I have never ever seen "other p with pulldown" except for some I made myself from silent films. As far as I know, all retail DVDs that began with framerates other than 24p are all hard telecined to 30i.
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