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────────────────────────────────
V : Log
Professional
Video Library
Management
────────────────────────────────
───────── Video Basics ─────────
Version 3
Copyright (C) 1988-1992 Sprenger Development
All Rights Reserved
─────────────────────────────────────────────────────────────────────
CONTENTS
Topic Page
----- ----
Introduction ................................ 2
Video Basics ................................ 3
Sound Basics ................................ 4
Time Code ................................... 4-5
Editing With Time Code ...................... 5-6
A Video Beginner's Glossary ................. 6-7
Page 1 - Video Basics
Introduction
─────────────────────────────────────────────────────────────────────
This documentation on the basics of video production
will NOT make you a video professional. The purpose
of this introductory information is to give a
simplified explanation and to define some basic
terminology, in particular on videotape, the editing
process, and time-code.
If you are reading this file because you want to
"break into" the video production business ... if you
have suddenly become responsible for a video produc-
tion for your company, your church, your favorite
civic or charitable organization, and have no idea
where to start ...
RUN - don't walk - to your local library and start
finding books on video production. Check out any
video trade journals in the periodicals; look for
video-oriented magazines at bookstores. Try to find
people who are or have been involved in video pro-
duction, and pump their brains. Don't be afraid
to look stupid, and don't give up until you get
answers.
Look for video production courses at the nearest
community college or university. Video classes
may be offered by the Education Department,
sometimes in Library Science, or you may get
lucky and find a full-blown video/film department.
Often seminars, classes, informational videotapes,
and other training resources are offered by video
companies. To find out about these, it may be enough
to send in the reader service cards from the video
trade journals mentioned above. This will usually
get you on mailing lists galore.
Learn to watch television and films with a critical
eye. You need to recognize good and bad production
work, and understand why it is good or bad. Try
watching sections of films or videos with the sound
turned down .. this is a good way to study lighting,
scene composition, editing techniques. Then watch
the same sections with the sound on, to learn what
effect audio has when combined with video.
Video production is a demanding business: difficult to
get into, often low-paying, usually with long hours
and hard work, both physical and mental. Whether you
want to get into the business full time, or simply have
become responsible for producing a single videotape,
you have your work cut out for you. Good luck, and
get started.
Because video production is FUN!
Page 2 - Video Basics
Video Basics
─────────────────────────────────────────────────────────────────────
Video is composed of a series of still images which,
when played back, create the illusion of movement.
Each still image is called a "frame". (Each frame is
made up of two "fields".) In standard video, there
are 30 of these still images which are shown every
second. This rate is called "30 frames per second".
Film is often shot and shown at 24 frames per second.
International video standards use other frame rates.
However, 30 frames per second is the American video
standard.
Videotape is recorded in a series of "tracks" or
"channels". These tracks are recorded in separate
strips on the videotape.
------------------------------------------------
..................... VIDEO ....................
------------------------------------------------
..................... AUDIO ....................
------------------------------------------------
..................... AUDIO ....................
------------------------------------------------
There is other information on recorded videotape,
such as a track called the "control track", which
allows a tape deck to play back the videotape
at the proper speed. On your home VCR, you may
have noticed that if you stop recording something,
then restart recording, the picture will break up
and show a lot of garbage on playback. The control
track is broken when you restart recording; it
takes the VCR a few seconds to regain control of
the tape during playback.
Professional video production also may utilize an
"address" track, which we will look at soon.
Sound Basics
─────────────────────────────────────────────────────────────────────
Normally there are two audio tracks, generally
referred to as channel 1 and channel 2, or track 1 and
track 2. Often on consumer videotapes, the same sound
is recorded on both audio tracks. Occasionally the
second track is used for things such as a foreign-
language translation.
In the world of video production, however, the two
audio tracks are used more often as separate entities.
The simplest kind of audio mixing involves adding a
Page 3 - Video Basics
music background or background audio or sound effects
to the second audio track. More sophisticated audio
postproduction involves pre-mixing audio as it is
recorded.
Time Code
─────────────────────────────────────────────────────────────────────
In order to perform professional quality editing and
other postproduction, precise control over the video-
tape is essential. "Time Code" is used to mark, or
label, each individual frame on a videotape.
Because each frame has its own unique number - a time
code number - this provides the frame-accurate control
which is required.
The industry standard time code format is called
SMPTE Time Code. SMPTE stands for "Society of Motion
Picture and Television Engineers".
SMPTE Time Code consists of four 2-digit numbers,
as in the example below.
01:22:03:14
Each of the four numbers has a specific meaning.
From left to right, they are: the "hour", then the
"minutes", the "seconds", and finally the "frames".
The sample time code shown above would translate to
"one hour, twenty-two minutes, three seconds and
fourteen frames."
During recording or playback, the frames number will
reach 29, then will wrap back to 0 and 1 will be
added to the seconds (30 frames per second, remember?).
The seconds and minutes number will wrap-and-carry upon
reaching 59, because of 60 seconds in a minute and
60 minutes in an hour.
The time code hour number is often used as a means
of identifying reels of tape. For example, on a
shoot you might start with a tape time coded with
hour 01. When that tape is full, you pop in reel
02 and continue shooting. Another reel identification
scheme must be used, of course, if the source reels
are greater than 60 minutes in length.
You can see how this simple scheme of numbering
provides frame-accurate control. By simply stating
a four-part time code number you can specify a
precise location ("address") on a videotape.
There are other benefits to using time-coding. By
giving two time code numbers - for example, the start
time and the stop time for a particular scene - it
is possible to calculate the exact length, or duration,
of the scene. No need to set counters or use a
stopwatch ... the time code numbers are all you need.
Page 4 - Video Basics
Just to confuse things, there are actually NOT 30
exact frames per second on American standard ("NTSC")
videotape. To be precise, it is a fractional number
of frames between 29 and 30. Because of this, video
can be time coded in a special way called "drop-frame"
time coding. This technique omits certain specific
frame numbers in the time code, to compensate for the
less-than-30-frame standard.
(This version of V:Log works only with non-drop frame
time code, which uses a full frame count. The
capability to handle drop-frame time code is anticipated
for inclusion in a future version .. near future!)
Time code is recorded on videotape in one of three
ways: on one of the audio tracks, on a separate, special
track called the "address track", or in an unused part
of the video track. The method of recording time code
is usually determined by the type of recording decks
that are used. The two methods which use an audio
signal are called "longitudinal"; time code which is
recorded in the video band is called "vertical interval"
time code.
Editing With Time Code
─────────────────────────────────────────────────────────────────────
Professional level postproduction is done using lots
of numbers - time code numbers. Most industrial
and broadcast quality editing equipment is today
controlled by a computer interface which simplifies
dealing with all those numbers.
A list of edits ("edit decision list", or "EDL") is
usually made up beforehand ("off-line"). Then that
list is fed into a computer-controlled video editor,
which can often perform much of the editing
automatically. This final editing is called "on-line"
editing. The off-line/on-line editing process is
used because of the high cost of renting an edit suite;
typically hundreds of dollars per hour.
It is during the off-line editing that the edit
decisions are made. Normally you will be provided
with copies of the "source" or "master" tapes: the
tapes from shooting. These special copies are
called "window dubs". They have the time code
keyed into the video, so that the time code can be
seen on the screen as you watch the tapes.
Creating an edit decision list consists of playing
the window dubs until you find the proper video for
a particular scene ... writing down the time code for
the start point ... then writing down the time code
for the end point, or setting a duration, which will
determine the end point time code. There are
exceptions. For some scenes, the video must end at
a certain point; the start point may be determined by
the required duration.
Page 5 - Video Basics
The type of audio to be used will also affect how
edit decisions are made. The preset length of music
or narration may determine the length of the video.
Or certain video may have to be shown (for example,
to illustrate a procedure in a training video), which
means that the audio timing will have to be flexible.
The final decisions as to timing of audio and video will
be determined by the communicative or artistic goals of
your production.
It is during the off-line editing process that V:Log
logs will prove most useful. If your source tapes have
been properly logged, you will be able to search for
and find scenes which meet your needs, instead of
scanning through tape .. after tape .. after tape.
In some situations there may be a library of source
video available from previous productions. Being able
to quickly and easily find video (or audio) which meets
your needs may save time and expense during shooting,
as well as during post-production.
A Video Beginner's Glossary
─────────────────────────────────────────────────────────────────────
Audio Mixing - Combining sound from two or more sources into a single
electronic signal, which is then recorded onto the Edited Master.
Control Track - A recorded track on the videotape which provides
playback machines the information needed to properly time and
control the playback.
Edited Master (tape) - The edited tape which the final program is
assembled onto, by recording video and audio in separate
pieces called "edits" or "events".
Editing Video - The process of copying sections of video and/or
audio from one or more sources (videotape, live camera output,
audiotape, graphics generators, etc.) onto an "Edited Master"
videotape.
Frame - A single video image. The successive display of frames
creates the illusion of movement in the picture.
Frame Rate - The number of frames per second which are displayed.
The video standard in U.S. television, governed by the NTSC,
is 30 frames per second.
Master (tape) - Usually the original camera reels which are recorded
while shooting. Also called "source" reels.
NTSC - National Television Standards Committee. The governing body
which determines electronic video signal formats, recording
formats, etc. in the U.S.
Off-line editing - Performing a rough edit, using equipment other
than the main edit equipment. The resulting Edit Decision List
is then used to create the actual Edited Master reel.
On-line editing - Creating the Edited Master reel using a primary
edit suite. Usually performed using an EDL made up during off-
line editing (see above).
SMPTE - Society of Motion Picture and Television Engineers.
Page 6 - Video Basics
Scan Lines - The fine lines which compose a video image on the
screen. Created by electronic guns sweeping back and forth,
which activate phosphor dots on the picture tube. These lines
of glowing dots - made up of red, green, and blue - create the
picture.
Time Code - A system of numbers recorded on videotapes which allows
precise identification of specific locations, or addresses, on
the tape. Standard SMPTE time code consists of four 2-digit
numbers, representing hours, minutes, seconds and frames.
Window Dub - A copy of original camera, or "source" footage, which
has the time code keyed into the picture. This allows playback
with time code, even on machines which do not have time code
capability. Generally used during off-line editing (see above).
Page 7 - Video Basics
