This FilmmakerIQ Lesson is proudly sponsored by RØDE Microphones Premium Microphones and Audio accessories for Studio, Live and Location Recording Welcome to Filmmaker IQ.com - I'm John Hess
and today we'll dive into the history of frame rates. Let's establish a basic truth about film. Nothing in the movies is real The sets are fake, the actors are pretending
and reciting lines written for them, even the very essence of moving pictures is a lie
- There's nothing moving, it's all an optical illusion. Take for instance this spinning wheel of circles
- it looks like it's moving clockwise but if we compare each frame of this animation,
we see that actually nothing is moving at all. We're just turning off circles sequentially
but when we flash these illustrations one after the other our brains create a sense
of movement. This is called the Phi Phenomenon first described
by Max Wertheimer in Gestalt psychology in 1912. The human brain can perceive about 10-12
individual frames per second. Faster than that and our brains blend the images together
into motion. So we've found our first frame rate - anything
higher than 12 frames a second. Simple, right? Well not so fast... With film we need to stop the projection as
we load up each frame otherwise we'll have a blurry mess. But Playing back 12 frames
per second with 12 intermittent periods of black as the film advances will create an
intolerable amount of flicker. How fast do you need to flash the images on screen to
make the flicker disappear? According to Thomas Edison - the magic number is 46 times
per second. At 46 frames per second, our persistence of vision kicks in and we won't notice the
screen going dark between every frame. But 46 frames per second meant you had to
run through a lot of film and that stuff isn't cheap. Film projectionists came up with a
unique solution - let's flash the same frame on the screen more than once. Using double or triple bladed shutters, you
could up the frame rate projected without running more film. Playing back a 16 frames
per second film using a triple bladed shutter, we would flash each frame 3 times for a total
of 48 frames per second - just above Edison's recommendation And that's our first commonly used frame rate
for silent film - 16 frames per second. Or there abouts. The inconsistency of silent
film frame rates have driven film historians and preservationists nuts, Early 20th century
cameras and projectors were hand cranked and cinematographers would undercrank or overcrank
the camera for effect, D.W. Griffith was notorious for undercranking his shots, shooting as low
as 12 frames per second. Even Edison ignored his recommediation. Exhibitors also played
fast and loose with the frame rate sometimes playing films back faster so they could squeeze
in one extra showing at the end of the day. In reality, silent film frame rates could range anywhere from 14 to
26 frames per second but that was okay as it didn't really ruin the effect of motion
pictures. That is until Sound came into the picture. The introduction of sound was one of the most
drastic technological and artistic changes in all of motion picture history. Because
sound was recorded as an optical track that ran alongside the film strip, recording and
playing back film had to be kept at a very strict and even frame rate - and that frame
rate would be established internationally in 1929 as 24 frames per second. Why 24? Well they found that the audio track
just didn't have enough fidelity on a 16 frames per second system. Using 48 projected frames
as our goal, they stepped up the next factorial - a 24 frame per second projection using a
double bladed shutter to keep to desired 48 projected frames per second Why 24 and not 23 or 25? Well that comes down
to basic math. 24 is number that can easily be divided 2, 3, 4, 6, and 8. So an editor
can know right off the bad that half a second is 12 frames. A third is 8 frames, a quarter
is 6 frames and so on. Why not a higher number like 30 or 32 which
also have the same factors. Like I said earlier, this stuff ain't cheap. 24 frames
was just the lowest easily divisible number that would work for sound. Ironically, the need for a consistent 24 frames per second created headaches in the sound department. The first sound cameras with their
whirling electric motors were very noisy - forcing camera operators to shoot from a soundproof
booth through a window. Technology and design did eventually catch
up, but the 24 frames per second frame rate is still very much with us today - almost
culturally ingrained into what we come to expect from the cinematic experience. Television had to deal with the same flicker
issues that plagued motion picture film - but flashing the same frame on screen was not
an option that was technologically feasible. Engineers more concerned about bandwidth,
something they were trying to conserve with over-the-air television broadcast. The solution was developed independently by
German Telefunken engineer Fritz Schr'ter in 1930 and in the US by RCA engineer Randall
C. Ballard in 1932. To conserve bandwitdth and avoid flickering - each frame would be
Interlaced - that is broken down into two alternating fields - an upper and a lower
field. Each field would be created on the screen one after the other in a comb like
pattern. In order to eliminate intermodulation - or a beating distortion caused by hum generated
in the electrical current, the refresh rate was set to that of the AC power- in the
United States, 60 hertz - so that each field is created in a 60th of a second resulting
in a full 30 frames per second. But the story gets more complicated with the
introduction of color. In 1948, the FCC put a moratorium on new television
broadcast licenses as it tried to figure out what to do with the newly available UHF spectrum.
The idea was introduce a new color system utilizing this higher frequency bandwidth
and let the older VHF channels which the older tv sets could access die off. While they were trying to figure out what to do, TV sales went through the roof exploding from 1 million sets to just
over 10 million in matter of a few years. The idea of letting older VHF TV stations
die off became impractical. So now the race was on to create a color standard
that was compatible with older black and white set. The NTSC, the board that created the
first US TV standards, reconvened with RCA leading the way using a system first outlined
by Georges Valensi in 1938. Breaking the image down into luminance and chrominance, broadcasters
could embed a color signal as a subcarrier in the television signal. New color TVs could
pick up and interpret this color subcarrier which would just be ignored by the older black
and white TV sets. So far so good - but there was a small problem.
The bandwidth used by the color subcarrier could potentially interfere with the audio
signal causing intermodular beating. The solution would be to reduce the frame rate by a factor
of .1% phasing the color and audio signals so that they would never full match up. In December 1953, the FCC adopted the RCA
system for color broadcast and we go from 60 fields per second, down to 59.94 fields
per second - for an effective 29.97 full frames per second. In a mathematically ingenious way of creating
a signal for both color and black and white television sets, we have these odd ball frame
rates that are still a big part of modern broadcasting standards. But that's only if you live in a country that
uses the NTSC standard. In 1963 German television manufacturer Telefunken released PAL to the
European broadcasting union with regular broadcasts in PAL starting in 1967. PAL was an format
designed to solve the color problems that plagued NTSC and would work with the 50 hertz AC power
used in Europe and elsewhere in the world. PAL along with a similar format SECAM run
at 50i for an effective 25 frames per second. So how do we get the cinematic 24 frames a
second to fit 60i video stream for say watching movies on video. Let’s walk through this process - First the 24 frames per second film is slowed
down by 0.1% giving us 23.976 frames per second. Now if we do the math we see that we need
to make 4 frames of 23.976 fit into 5 frames of 29.97 We do this spitting up the frames into fields
using a 3:2 pulldown. The first frame is captured onto three fields - the upper, lower and then
upper field - that’s one and one half frames. Then the next frame is captured on the following
two fields, lower field and then upper. The next frame fills up the lower, then following
upper and lower with the last frame filling the upper and lower. So we have 3 fields, 2 fields 3 fields 2 fields . That’s your
3:2, 3:2 cadence. Unfortunately this process isn’t perfect with resulting video stream having Telecine Judders every 3 frames which is especially noticeable on long slow camera
movements. Reverse Telecine or Reverse 3:2 pulldown are
technologies that work backgrounds, constructing a true 23.976 or 24p video stream from the 3:2 pulldown 60i footage. Most modern digital cameras can avoid the telecine process altogether and record
23.976 or straight 24 frame rates natively on to the hard drive but there are some workflows that run video through HDMI cables which are rated for 60i, may still utilize the 3:2 pull down. For telecining film onto PAL or SECAM’s
25 frames per second, the process is much simpler Using a 2:2 Pulldown, the 24 frame
per second footage is sped up by 4% and each frame is transfered onto two fields - an upper
and lower field. The increased speed raises the pitch of the audio by a noticeable 0.679
semitones or a little more than a quarter step musically but can be adjusted down using
a pitch shifter. 24 frames has been the standard for narrative
film for nearly a century now. But enterprising filmmakers have tried to push the temporal
resolution or frame rate higher - trying to reduce motion blur to create smoother and
more realistic look. One of the notable experiments in high frame
rate is Showscan - a 70mm format developed by Visual Effects Wizard Douglas Trumbull
- who’s famous for developing many of the visual effects for Stanley Kubrick’s 2001:
A Space Odyssey. Running at 60 frames per second, Showscan created a stronger biometric
response in test audiences, but the process just never found use in narrative film - being
used mainly in motion simulator rides. More recently Trumbull has worked on a digital Showscan - shooting at 120 frames per second and adjusting the play back anywhere from
24 to 120 frames depending on the needs of the shot. But audiences just haven’t been warm to
high frame rate in narrative film - the most recent experiment was Peter Jackson’s “The
Hobbit” presented in 48 frames per second. Variety reviewed the film and complained that
the “human actors seemed overlit and amplified in a way that many compared to modern sports
broadcasts or daytime television. One projectionist complained that "it looked like a made-for-TV movie" But filmmakers at the technological bleeding edge, people like Peter Jackson or James Cameron, still push for higher frame rates. Will the future of narrative filmmaking leave 24p behind? The technology is already here - the new 4K standards are capable of up to 120
frames per second. While these high frame rates may be great for recreating the immediacy
of sports broadcasts or really good 3D or for video games - to this filmmaker there’s just something cinematic about the cadence of 24 frames per second. For all it’s drawbacks in clarity and motion blur
It’s just how we grew up watching movies. Maybe the next generation will grow up high
frame rates and see 60p the new cinematic look - or maybe not. Frame rate is engine behind the cinematic
lie - the magic trick that allows us to enter a world not quite real but real enough. A simple defining number shaped
by psychology, economics and clever engineering all in service to the act of telling stories. So
use it. Use that engine and go make something great. I’m John Hess and I’ll see you
at FilmmakerIQ.com
So with my work as a videographer, i can tell you there is a very noticeable difference between 30, 60 and 120 FPS.
Very informative video. Thing I can't understand is that people complained about Hobbit @48 fps. It looked odd, but that's mostly because people watched movies @24 fps their whole life, that's fucking normal. After watching last Hobbit in HFR, I am never going back to lower frame rate when higher is possible.
I recommended HFR Hobbit to most of my frames saying, that it will look odd, sort of fast, but they need to focus on how smooth it is, not how different (if it makes any sense). All of them liked it and if you go to a cinema with open mind, not to bitch about tv-like experience, you will surely like it.
TL;DR High framerates for both movies and games FTW
John Hess is the shit. You should all check out more of his videos.
"Cinematic"
It would have been interesting if he talked about fps in games a bit more.
Cool stuff bro
Leave it to a filmmaker to create a web video at 24fps and say that HDMI is interlaced.