Imagine trying to use words to describe every scene in a film, every note in a song, or every street in your town. Now imagine trying to do it using only the numbers 1 and 0. Every time you use the Internet to watch a movie, listen to music, or check directions, that’s exactly what your device is doing, using the language of binary code. José Américo N L F de Freitas explains how binary works.
Lesson by José Américo N L F de Freitas, animation by Qa’ed Mai.
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Content
6.777 -> Imagine trying to use words
to describe every scene in a film,
11.415 -> every note in your favorite song,
13.318 -> or every street in your town.
16.035 -> Now imagine trying to do it using
only the numbers 1 and 0.
20.859 -> Every time you use the Internet
to watch a movie,
23.754 -> listen to music,
24.863 -> or check directions,
26.349 -> that’s exactly what your device is doing,
28.859 -> using the language of binary code.
31.812 -> Computers use binary because
it's a reliable way of storing data.
36.502 -> For example, a computer's main
memory is made of transistors
40.577 -> that switch between either high
or low voltage levels,
44.154 -> such as 5 volts and 0 volts.
47.644 -> Voltages sometimes oscillate,
but since there are only two options,
51.75 -> a value of 1 volt
would still be read as "low."
55.751 -> That reading is done by
the computer’s processor,
58.28 -> which uses the transistors’ states
to control other computer devices
62.595 -> according to software instructions.
64.791 -> The genius of this system
is that a given binary sequence
68.132 -> doesn't have a pre-determined meaning
on its own.
71.52 -> Instead, each type of data
is encoded in binary
75.205 -> according to a separate
set of rules.
78.115 -> Let’s take numbers.
79.497 -> In normal decimal notation,
81.179 -> each digit is multiplied by 10 raised
to the value of its position,
86.032 -> starting from zero on the right.
88.483 -> So 84 in decimal form is 4x10⁰ + 8x10¹.
95.04 -> Binary number notation works similarly,
97.755 -> but with each position
based on 2 raised to some power.
101.561 -> So 84 would be written as follows:
105.573 -> Meanwhile, letters are interpreted
based on standard rules like UTF-8,
110.376 -> which assigns each character to a specific
group of 8-digit binary strings.
115.483 -> In this case, 01010100 corresponds
to the letter T.
122.389 -> So, how can you know whether
a given instance of this sequence
126.147 -> is supposed to mean T or 84?
128.832 -> Well, you can’t from seeing
the string alone
131.87 -> – just as you can’t tell what the sound
"da" means from hearing it in isolation.
136.442 -> You need context to tell whether you're
hearing Russian, Spanish, or English.
141.279 -> And you need similar context
142.67 -> to tell whether you’re looking
at binary numbers or binary text.
146.785 -> Binary code is also used for
far more complex types of data.
151.146 -> Each frame of this video, for instance,
153.492 -> is made of hundreds
of thousands of pixels.
155.96 -> In color images,
157.641 -> every pixel is represented
by three binary sequences
161.095 -> that correspond to the primary colors.
163.701 -> Each sequence encodes a number
165.487 -> that determines
the intensity of that particular color.
168.671 -> Then, a video driver program transmits
this information
172.6 -> to the millions of liquid crystals
in your screen
175.31 -> to make all the different hues
you see now.
178.088 -> The sound in this video
is also stored in binary,
181.402 -> with the help of a technique
called pulse code modulation.
184.806 -> Continuous sound waves are digitized
187.19 -> by taking "snapshots" of their
amplitudes every few milliseconds.
191.582 -> These are recorded as numbers
in the form of binary strings,
195.247 -> with as many as 44,000
for every second of sound.
199.16 -> When they’re read by
your computer’s audio software,
201.77 -> the numbers determine how quickly
the coils in your speakers should vibrate
206.124 -> to create sounds of different frequencies.
208.965 -> All of this requires billions
and billions of bits.
212.66 -> But that amount can be reduced
through clever compression formats.
216.663 -> For example, if a picture has 30 adjacent
pixels of green space,
221.171 -> they can be recorded as "30 green" instead
of coding each pixel separately -
226.019 -> a process known as run-length encoding.
229.194 -> These compressed formats are themselves
written in binary code.
234.094 -> So is binary the end-all-be-all
of computing?
237.164 -> Not necessarily.
238.549 -> There’s been research
into ternary computers,
240.967 -> with circuits in three possible states,
243.432 -> and even quantum computers,
245.252 -> whose circuits can be
in multiple states simultaneously.
248.916 -> But so far, none of these has provided
251.339 -> as much physical stability
for data storage and transmission.
254.635 -> So for now, everything you see,
257.079 -> hear,
257.848 -> and read through your screen
259.464 -> comes to you as the result
of a simple "true" or "false" choice,
