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  1. Hello

    I would like to invert telecine of an original 25p source converted to NTSC with 3:2:3:2:2 pulldown.

    Here is the code I wrote:

    Code:
    AssumeTFF()
    TFM()
    TDecimate(mode=2,rate=25)
    AssumeFPS(25)
    However TDecimate() removes some frames that are not duplicates on one hand and leaves some duplicate frames on the other hand. I'm wondering if there is a better way to retrieve the original 25p source without duplicates or missing frames.

    Here you can have a look at a short sample of the video I'm working on:
    http://www.mediafire.com/?2v3jb55nyr9e5zu

    Any advice will be appreciated.

    Thank you in advance

    Max
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  2. It worked pretty well here. I saw only saw one duplicate frame in the 263 frame result. The d2v file doesn't match your m2v file. Try rebuilding it.
    Last edited by jagabo; 25th Sep 2013 at 11:21.
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  3. Try TDecimate(cycle=6, cycleR=1). That will give you 24.975 fps with no duplicates or drops. Ie, the source was slowed to 24.975 fps then went through straight 3:2:3:2:2 pulldown to create 59.94 fields per second.
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  4. Thank you for your answer.

    I realized that I posted the thread in the wrong place.. I thought I was posting it in 'Video Conversion' section which seems more appropriated.. but I failed at some point.

    I tried to rebuild and to use TDecimate(cycle=6, cycleR=1), but there are still some drops. For example between frame 831 and 832 in this new sample:

    http://mathmax.mynetdomain.de/tdecimate.rar
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  5. You're going to have to face the fact that decimation like this may never be perfect. Especially in a shot like that with little motion and a lot of noise.

    You're lucky in that your video has numbered frames. You can examine the long run frame count to determine what the final rate should be. The difference between 24.976 and 25 would be 1 frame out of every 1001.
    Last edited by jagabo; 25th Sep 2013 at 19:51.
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  6. ah you're right. But that not exactly 1 frame out of every 1001.. sometimes between every 990-1000 frames (I look at the video after applying your script). Strange. Anyway, my best chance may be to look at the part around every 1000 frames and to add them manually, right?
    Last edited by mathmax; 25th Sep 2013 at 20:16.
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  7. See if this works. I'll let you do the counting:

    TFM()
    TDecimate(m2PA=True,maxndl=6,Mode=2,Rate=25.0)

    If that's no good, then you can try bobbing it and letting SRestore do the decimating:

    Yadif(Mode=1)#or the better QTGMC
    Srestore()

    Both give back 25fps which may be the correct framerate for this one.

    MPEG2Source("sample.d2v")
    AssumeTFF()
    TFM()
    TDecimate(cycle=6, cycleR=1)
    AssumeFPS(25)

    I guess you know that AssumeFPS line changes the length and throws the audio out of synch?
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  8. Originally Posted by manono View Post
    TFM()
    TDecimate(m2PA=True,maxndl=6,Mode=2,Rate=25.0)
    That worked pretty well. I trimmed the start of the file so that a 0 was at frame 0, then verified that there was a 0 at every 50 frame interval. Of course, it's possible that there was a drop and a duplicate in between those but I'll let the OP check that himself.
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  9. TFM()
    TDecimate(m2PA=True,maxndl=6,Mode=2,Rate=25.0)
    I checked carefully. This one is perfect !
    Well.. there was only one mistake in the whole clip.. but that was because one frame was missing in the original pulldowned clip (the timecodes show that one frame was droped).

    Thank you so much for your help jagabo and manono!
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  10. Formerly 'vaporeon800' Brad's Avatar
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    If you're a perfectionist/masochist and the pattern is consistent throughout, it's also possible to reverse it manually, but a longer sample is required to see a repeat in the pattern. (More than 1000 frames, I guess.)

    Originally Posted by jagabo View Post
    You're going to have to face the fact that decimation like this may never be perfect. Especially in a shot like that with little motion and a lot of noise.
    Err, the camera is moving for 90% of the clip. And shouldn't the grain actually aid in differentiating the correct original frames since it's from the source and not the converted medium?
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  11. Originally Posted by vaporeon800 View Post
    shouldn't the grain actually aid in differentiating the correct original frames since it's from the source and not the converted medium?
    If the noise is from being recorded onto video tape it has nothing to do with the original film frames.
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  12. If you're a perfectionist/masochist...
    I am.. but well, since I got a solution to do this automatically, that's enough

    I'm wondering why the source is 25p originally. Isn't it strange that the original source is not interlaced? Or do you think it was interlaced and then half of the fields were dropped before pulldown?
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  13. Originally Posted by mathmax View Post
    I'm wondering why the source is 25p originally. Isn't it strange that the original source is not interlaced? Or do you think it was interlaced and then half of the fields were dropped before pulldown?
    It was probably shot on film, sped up to 25 fps for PAL broadcast and recording, then a 25p PAL tape was converted to NTSC with 3:2:3:2:2 pulldown.
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  14. Formerly 'vaporeon800' Brad's Avatar
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    Is this a DVD extra?

    Originally Posted by jagabo View Post
    Originally Posted by vaporeon800 View Post
    shouldn't the grain actually aid in differentiating the correct original frames since it's from the source and not the converted medium?
    If the noise is from being recorded onto video tape it has nothing to do with the original film frames.
    Right, but in this case it doesn't really change much from field to field; just some compression artifacts shift around.
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  15. Originally Posted by jagabo View Post
    Originally Posted by mathmax View Post
    I'm wondering why the source is 25p originally. Isn't it strange that the original source is not interlaced? Or do you think it was interlaced and then half of the fields were dropped before pulldown?
    It was probably shot on film, sped up to 25 fps for PAL broadcast and recording, then a 25p PAL tape was converted to NTSC with 3:2:3:2:2 pulldown.
    Ah ok. I wonder I should speed down to 24 fps for watching on computer with original sound (normal pitch). What do you think?
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  16. Originally Posted by mathmax View Post
    Ah ok. I wonder I should speed down to 24 fps for watching on computer with original sound (normal pitch). What do you think?
    I always do. Actually to 23.976fps for DVD.
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  17. Originally Posted by manono View Post
    Originally Posted by mathmax View Post
    Ah ok. I wonder I should speed down to 24 fps for watching on computer with original sound (normal pitch). What do you think?
    I always do. Actually to 23.976fps for DVD.
    Ah, thank you. But I wonder if I should change the tempo (keep the same pitch) or change the speed (which would pitch down the audio). When the video was sped up to 25fps, what do you think was applied?
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  18. Originally Posted by mathmax View Post
    ...what do you think was applied?
    I haven't a clue in your case. For the films with which I work the pitch has been shifted and I always shift it back. I believe that in most cases, speeding up the audio for PAL also results in a pitch shift. Ask a musician friend to figure it out for you.
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  19. Originally Posted by mathmax View Post
    When the video was sped up to 25fps, what do you think was applied?
    Given the age of the video I suspect the pitch is up by the same amount as the frame rate. To tell for sure you'd have to compare voice or music samples with a known reference.
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  20. Thank you. I compared with another concert, and the pitch is the same. So probably the tempo was changed when converting from 24fps to 25fps without altering the pitch.
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