framerate question

[Aseesl8er]

If I shot footage at 24fps, then telecined it to mini-DV, then played it back on my miniDV camcorder, would the framerate of the footage change since it's in dv? video is for the most part 30fps. Would the new video come out a little bit faster than what I shot?

[sooper8fan]

I've wondered this as well. I'm not crystal'd so I'm not running at exactly 24fps....I look forward to finding out the answer too.

Aseesl8er, are you a fan of Saved By The Bell?

[drsanchez]

If I shot footage at 24fps, then telecined it to mini-DV, then played it back on my miniDV camcorder, would the framerate of the footage change since it's in dv? video is for the most part 30fps. Would the new video come out a little bit faster than what I shot?

Nope. Unless you use a Workprinter, where each frame of film is copied to each frame of video. In that case, your video will play about 25% faster than you intended. Otherwise, there's some super complex way of doubling frames using the square root of the something something, which results in your movie playing at its correct speed on the video.
It's just like if you transferred off the wall with a projector and a video camera. Your projector is going at 24 fps, your video is recording at 30 fps, yet playing it back on video looks normal.

[reflex]

It depends what you mean by "telecined it to mini-DV."

If you're projecting film onto a wall and shooting it with a video camera, the speed will appear correct, although there will be some flicker.

If you're using something like a Workprinter or high-end telecine, each frame of your movie will be captured onto the computer individually. To copy it to miniDV, a process called pulldown is used to convert your original 24fps film to ~29.97 fps.

It works like this:

1. The film speed is "pulled down" by 0.1% to 23.976 fps. Hence the term "pulldown"

2. NTSC video runs at approximately 29.97 fps (it's actually 30/1.001 Hz). If you do a little math, you'll discover that there are exactly 4 frames of film (at 23.976fps) for every 5 full video frames (at 29.97 fps).

3. The four film frames are "stretched" across five video frames. People often incorrectly refer to this as a "3:2 pulldown," but it's actually something slightly more complicated.

And thus, a miracle has occurred.

The resulting video will run 0.1% slower than it was originally shot, which will be absolutely unnoticable unless you're trying to synchronize sound.

[Aseesl8er]

I've wondered this as well. I'm not crystal'd so I'm not running at exactly 24fps....I look forward to finding out the answer too.

Aseesl8er, are you a fan of Saved By The Bell?

Haha, yes, I was once a fan. But my friends gave me that nickname after the character. Not because I resemble Mario Lopez but because of my initials.

So back to the question at hand. What is a workprinter? Pardon my ignorance. What is being crystaled? If i'm trying to shoot a short film, then transfer it onto mini-DV, my footage would be faster? I'm assuming I'm going to have major problems with synching audio. Pretty confused at the moment. Any workflow method suggestions for what I'm doing in my telecine would be really helpful. Thanks again.

[Aseesl8er]

It depends what you mean by "telecined it to mini-DV."

If you're projecting film onto a wall and shooting it with a video camera, the speed will appear correct, although there will be some flicker.

If you're using something like a Workprinter or high-end telecine, each frame of your movie will be captured onto the computer individually. To copy it to miniDV, a process called pulldown is used to convert your original 24fps film to ~29.97 fps (it's actually 30/1.001 Hz, so around 29.97002997002997002997002997003 frames per second).

The resulting video will run 0.1% slower than it was originally shot, which will be absolutely unnoticable unless you're trying to synchronize sound.

Well, the local place where I'm telecining it does not use a rank according to them. They use a film chain process that uses ELMO factory ETC telecine machines with Sony multiplexors. They capture to 3 chip cameras. Then they can transfer it onto VHS, DVD or miniDV. I'm assuming they're not using a rank or any scanning of individual film frame. I don't know if they use a pulldown method. Do you think my transferred footage will be grossly off from the original shot footage speed?

Thanks for the earlier explanation. That was very helpful.

[tlatosmd]

What is being crystaled?

It's a modern way to have a camera modificated to run at exact framerates, down to several figures following the decimal point.

If i'm trying to shoot a short film, then transfer it onto mini-DV, my footage would be faster? I'm assuming I'm going to have major problems with synching audio.

It'll only be faster if you'll transfer to PAL as PAL runs at 25fps and thus, 24fps film footage is sped up to 25fps to transfer to PAL.

In NTSC, it's not faster, it's slower, by 0.1%, as Reflex noted correctly. Your 24fps footage will move at 23.976fps by copying each 4th film frame to the 5th video frame (pattern: frame #1, #2, #3, #4, #4, #5...and so on), that's the 'pull-down' part. At least that's what it's like with decent telecining. It's easy to remain in-sync by speeding up your audio by 0.1% as well.

If you simply use a camera to shoot your film from the screen it'll remain at the same speed but it's the worst option there is, as Reflex mentions:

If you're projecting film onto a wall and shooting it with a video camera, the speed will appear correct, although there will be some flicker.

Furthermore, if you'll use a video camera like that (no matter it has one CCD or three of'em), you'll not only encounter flicker but also dirt, hotspot, blurred motions, lack of correct focus, breathing and pumping of focus, reduced contrast range, color casts, and the results of poor registration (basically all that makes up contemporary bad reputation of cine-film).

Individual frame-by-frame capture at home such as by using the workprinter is a far better solution than that, you'll just have to apply a preset pulldown pattern in case you're transferring to NTSC, and you'll be at the 0.1% slowdown rate.

[audadvnc]

I need to add a few comments and corrections to this thread.

The film speed is "pulled down" by 0.1% to 23.976 fps. Hence the term "pulldown"

Although the rest of reflex's and tlatosmd's explanations are correct, the above is an incorrect definition of pulldown. The term refers specifically to getting the 24fps film onto 30 frames of video. The definition, courtesy PC magazine:

A technique used to convert movie film to interlaced video such as NTSC. Also called the "telecine" process, 3:2 pulldown is required because film, which is run at 24 fps (frames per second), does not divide evenly into 30 fps for interlaced video (29.97 fps to be exact).

http://www.pcmag.com/encyclopedia_term/ ... 020,00.asp

Back to Aseesl8er's initial question:

would the framerate of the footage change since it's in dv?

You can telecine film to video at any speed you want. Normal transfer is at 24fps to accomodate sync sound requirements, but (depending on the telecine's capabilities) you can transfer slower or faster than normal speed. For example, old silent newsreels and movies were often undercranked, often at 12fps in the Mack Sennett flicks, to save on camera stock costs. To transfer them at correct speed you run the telecine at 12fps film speed. The video output is always 29.97 (NTSC) or 25 (PAL); video speed never varies.

On film chains vrs telecine machines: Generally, film chains cannot provide as clear a transfer as can telecine machines. However, some of the better film chains make excellent transfers, fully the match of a mid-level telecine. The transfer house I work with (Cinesound, Mpls) uses a telecine machine for Super 8, 16mm and 35mm formats and an old Bell & Howell film chain with Sony 3 chip camera for Regular 8. I've seen stunningly good footage come off that R8 film chain (old Kodachrome R8 from the 40's looks really nice).

[tlatosmd]

For example, old silent newsreels and movies were often undercranked, often at 12fps in the Mack Sennett flicks, to save on camera stock costs.

This reminds me of a British Sherlock Homes series from the 30s and 40s. It looks like it was shot at 12fps silent, copied to 24fps sound prints while keeping a 1:1 frame ratio from original to print so movements look twice as fast, then the films were dubbed and audio mixed to people and things moving at double the speed as natural.

[audadvnc]

In the USA, one of the most popular reruns in syndication has been M*A*S*H. The episodes were originally 28 minutes long. When the show went into syndication, the stations wanted the episodes cut to 22 minutes to allow for more commercials, but didn't want to re-edit the episodes. They originally sped up the projection speed, but the voices pitched up so that the actor's delivery didn't sound realistic.

So Lexicon, an early digital audio effects company, was commissioned to make a "pitch shifter" that would bring the pitch of the voices down to normal even though the speech delivery stayed faster. Lexicon succeeded; this was their big break that led to their dominance of digital reverbs and effects in the audio studio world.

[reflex]

The film speed is "pulled down" by 0.1% to 23.976 fps. Hence the term "pulldown"

Although the rest of reflex's and tlatosmd's explanations are correct, the above is an incorrect definition of pulldown. The term refers specifically to getting the 24fps film onto 30 frames of video. The definition, courtesy PC magazine:

Modern NTSC telecine (interlaced) nearly always uses a 2-3 pulldown (Which places the A frame as the head frame). 3:2 is an anachronism -- most modern telecine devices do the reverse. Perhaps PC Mag should stick to computers? ;)

Let's imagine you have four film frames named A B C D and want to convert them to interlaced NTSC. They become:

AA (Remember, interlaced video displays two fields per frame)
BB
BC
CD
DD

To be comprehensively correct, it's referred to as "2-3,2-3 pulldown" -- two fields of A, three of B, two of C, three of D. If you're working in High-Def, things become a pure "2-3" because 480p displays full frames.

You will also see something referred to as 2:3:3:2. I'll leave that one for another poster to explain.

Nice explanation for Avid users here:

http://www.zerocut.com/tech/pulldown.html

[audadvnc]

The film speed is "pulled down" by 0.1% to 23.976 fps. Hence the term "pulldown"

Although the rest of reflex's and tlatosmd's explanations are correct, the above is an incorrect definition of pulldown. The term refers specifically to getting the 24fps film onto 30 frames of video. The definition, courtesy PC magazine:

Modern NTSC telecine (interlaced) nearly always uses a 2-3 pulldown (Which places the A frame as the head frame). 3:2 is an anachronism -- most modern telecine devices do the reverse. Perhaps PC Mag should stick to computers? ;)

Let's imagine you have four film frames named A B C D and want to convert them to interlaced NTSC. They become:

AA (Remember, interlaced video displays two fields per frame)
BB
BC
CD
DD

To be comprehensively correct, it's referred to as "2-3,2-3 pulldown" -- two fields of A, three of B, two of C, three of D. If you're working in High-Def, things become a pure "2-3" because 480p displays full frames.

You will also see something referred to as 2:3:3:2. I'll leave that one for another poster to explain.

Nice explanation for Avid users here:

http://www.zerocut.com/tech/pulldown.html

Agreed. But my point was that pulldown isn't a result of the color-based 29.97 video speed. IIRC 3:2 pulldown or whatever you want to call it was even used in the old days of B&W television that ran at 30.00, not 29.97 .

[tlatosmd]

In the USA, one of the most popular reruns in syndication has been M*A*S*H. The episodes were originally 28 minutes long. When the show went into syndication, the stations wanted the episodes cut to 22 minutes to allow for more commercials, but didn't want to re-edit the episodes. They originally sped up the projection speed, but the voices pitched up so that the actor's delivery didn't sound realistic.

When was that? As much as I know, The Beatles used something like that on Strwaberry Fields forever in December 1966/January '67 because John wanted his voice and some instruments to change pitch one key inbetween verses and chorus, but not speed, and they didn't want to re-record stuff.

And BTW, please keep it simple guys, Aseesl8er only wonders whether his telecined footage will run faster or slower, and at what rate.

[reflex]

Agreed. But my point was that pulldown isn't a result of the color-based 29.97 video speed. IIRC 3:2 pulldown or whatever you want to call it was even used in the old days of B&W television that ran at 30.00, not 29.97 .

Interesting, Mr. Hughes. Never thought of it in those terms; perhaps pulldown refers literally to the transport of film.

Interesting that you mention that M*A*S*H was sped-up. I dimly remember seeing something in the press quite a few years ago about Star Trek. Some die-hard Trekkies were upset because the original series had been sped up and pitch shifted to allow for more commercials.

[audadvnc]

In the USA, one of the most popular reruns in syndication has been M*A*S*H....

When was that? As much as I know, The Beatles used something like that on Strwaberry Fields forever in December 1966/January '67 because John wanted his voice and some instruments to change pitch one key inbetween verses and chorus, but not speed, and they didn't want to re-record stuff.

Lexicon was formed in 1971, long after the Beatles.

When you listen to "Stawberry Fields", you will hear John's voice quality (also known as formant) drop a half step between the first verse (played by the guitar band in A major) and the second verse (orchestrally scored). The second half of the song was pitched down a half step in playback (as the orchestra originally played the song a half step higher - in B flat - than the band did). It was a practical continuity decision on George Martin's part , but adds to the air of sadness and dreamy nostalgia the song generates.

And BTW, please keep it simple guys, Aseesl8er only wonders whether his telecined footage will run faster or slower, and at what rate.

But it is a technical issue he brings up with an interesting history and a technical explanation needed to answer.