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what is 3:2 pull down mean?


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#1 of 10 paul watkins

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Posted February 20 2003 - 01:17 AM

what is this feature?

toshiba 50hdx82 has it listed as a feature.

#2 of 10 ManW_TheUncool

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Posted February 20 2003 - 03:04 AM

Hmmm... I was going to point you to the HTF primer, but noticed that it makes no mention of 3:2 pulldown.

Basically, it's the method of choice for converting film-based content from interlaced to progressive scan video, ie. deinterlacing. You will sometimes hear the term reversed/inverse 3:2 pulldown (or even 2:3 pulldown). Those are the more accurate terms since 3:2 pulldown is actually the method used to convert film to interlaced video, but everyone gets lazy about it. Posted Image

It's good to have it on the TV, and just about all current HDTVs have it although they might not always call it that. Nowadays, the more difficult thing w/ deinterlacing that separates the good and the average is w/ video-based content and the ability to switch between the 2 modes. The Tosh is said to be pretty good at this also.

Since you don't seem to know anything about 3:2 pulldown, you might eventually want to know more, especially in relations to DVD. Check this link for more details along that line and on what I already mentioned:

http://www.hometheat....e-10-2000.html

_Man_
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#3 of 10 Jeff Pounds

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Posted February 20 2003 - 03:08 AM

Paul,

First off, welcome to HTF! Posted Image

I'm no video expert, but I can tell you basically what 3:2 pulldown is...

Movies that are shot on film run a 24 frames per second. However, NTSC video signals are made of interlaced "fields" instead of "frames" and runs at nearly 30 frames per second.

Therefore, the 3:2 pulldown process is used to transfer film to video.

However, 3:2 pulldown is what gives films transferred to video that "video" look if that makes any sense.

The function on the TV is actually "reverse" 3:2 pulldown (even though most TVs list the feature as simply "3:2 pulldown") and what it does is basically changes the interlaced display to a progressive display, making it more "film like".

If there is someone else who is more technically inclined, they can chime in.

Also, you may want to look at this link for a complete description.

Admins, I apologize for linking outside of HTF, but I couldn't find a comprehensive descriptions of 3:2 pulldown in the HTF beginners' primer...

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#4 of 10 Modena

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Posted February 20 2003 - 03:22 AM

Do you need to engage 3:2 pulldown? I've always wondered about this, or does it just happen automatically? I would like to see the difference between having it or not.

#5 of 10 ManW_TheUncool

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Posted February 20 2003 - 04:04 AM

Since just about all current HDTVs have it, it's not a real choice to not have it. In the past, many did require a manual switch, but nowadays, they do it automatically. But as I said before, the detection capability between 3:2 pulldown and video-based deinterlacing might vary. FWIW, this is especially true for deinterlacing in DVD players.

Also, some TVs might still allow you to disable deinterlacing, which might sometimes be desirable for video-based content, but that's probably going away for good also. Kinda like how some TV makers are favoring 540p/1080i upconversion to cut costs.

If you don't have 3:2 pulldown and use video-based deinterlacing for film-based content, you will likely get a softer and/or more jagged picture w/ possible combing artifacts. It all depends on how the linedoubler works.

_Man_
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#6 of 10 Kevin. W

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Posted February 20 2003 - 12:44 PM

Quote:
TVs might still allow you to disable deinterlacing


If the TV has it and so does the DVD player which one prevails over the other if you can't disbale it in the tv?

Kevin

#7 of 10 ManW_TheUncool

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Posted February 20 2003 - 01:46 PM

Kevin,

I meant disabling TV deinterlacing for a 480i signal. It's a non-issue for 480p--no deinterlacing can/need be done.

_Man_
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"Whatever is true, whatever is honorable, whatever is right, whatever is pure, whatever is lovely, whatever is of good repute, if there is any excellence and if anything worthy of praise, dwell on these things..." (St. Paul)

#8 of 10 TyR

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Posted March 16 2003 - 01:48 PM

Will all progressive scan DVD players eliminate the 3:2 pulldown artifacts with the reverse process, or will only some do so? Is it more preferable for the TV to do it than it is for the DVD player to do so?

Also, can anyone confirm whether I'm correct in thinking that, e.g., the Samsung TXM3296HF does not have the 3:2 pulldown option, while the TXM3297HF does?

#9 of 10 ManW_TheUncool

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Posted March 17 2003 - 05:06 AM

Check this link for a good (long) read on this subject:

http://www.hometheat....e-10-2000.html

The short answer is that if both DVD player and TV has equally good deinterlacing, it's preferable to do it in the player to avoid the extra D->A->D conversion, which results in some resolution loss, unless you're using a digital connection to avoid that conversion.

Anyway, it's still good to have good deinterlacing in the TV for other video sources, but preferable to have a good player do it for DVDs.

_Man_

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#10 of 10 Jonathan Kaye

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Posted March 17 2003 - 11:07 PM

Quote:
However, 3:2 pulldown is what gives films transferred to video that "video" look if that makes any sense.

Depends what you mean by the "video" look. If you mean a stuttering of the image because a 24fps source is stretched to fit a 60 fields per second picture, then you're right.

To me, the "video" look is more to do with the method of capturing the image. If an image is captured on a video (i.e. interlaced) camera, then it has a more fluid video look to it than if captured on a progressive camera, which gives a more filmic look.

The difference between the two "looks" is quite noticeable in a single piece of television; most British drama (especially BBC) of the 60's, 70's and 80's used film cameras for location work and video cameras for studio work, leading to a marked change in look in consecutive shots!
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