Download Advanced Static and Dynamic Visualization

Video-Editing
Techniques
Sci Vis
V204.03
Video Post-Production.


Creating an animation
using a program such
as 3D Studio Max or
trueSpace is often just
a part of a total video
production process.
Video editing software
(such as Adobe
Premiere) offers the
opportunity to
enhance animation
productions with
sound, still images,
and scene transitions.
Video Post-Production.


The addition of sound
can add realism and
interest to a video
production.
Titles and single
images (static or
scrolling) provide
additional information.
Digital Versus Analog


Analog (linear) devices
record light and sound as
continuously changing electrical signals
described by a continuous change of
voltage.
Digital recordings are composed of a series
of specific, discrete values which are
recorded and manipulated as bits of
information, which can be accessed or
modified one bit at the time or in selected
groups of bits.
Digital Versus Analog

Digital media is stored in a
format that a computer can
read and process directly.
 Digital cameras, scanners,
and digital audio recorders
can be used to save images
and sound in a format that
can be recognized by
computer programs.
 Digital media may come
from images created or
sound recorded directly by
computer programs.
Digital Versus Analog

Analog media must be digitized or converted to
a digital format before using a computer
 Analog images may be obtained from such
sources as older video cameras working with
VHS or SVHS. Analog sounds may come
from sources such as audiotapes and
recordings.
 Hardware devices such as a video capture
card must be attached to the computer to
bring analog materials into computer video
editing programs.
Digital Versus Analog

Sufficient computer
resources are needed
for digital video
editing.
 Fast processors
needed to process
the video.
 Additional RAM
beyond customary
requirements is
needed.
Digital Versus Analog



Very large hard
drives are needed.
Few minutes of
footage require vast
amounts of storage.
Video cards should be
capable of working
with 24-bit color
depth displays.
Large monitors are
better due to the need
to work with
numerous software
displays.
Specifying Project Settings



Selecting settings can be a
complex task requiring an
understanding of input
resources and output goals.
The ability to make good
decisions regarding capture,
edit, and output settings
require an understanding of
topics such as frame rates,
compression, and audio.
Numerous books can help
but Experience is still a
really good teacher.
Specifying Project Settings

Timebase specifies
time divisions used to
calculate the time
position of each edit,
expressed in frames
per second (fps).
 24 is used for
editing motionpicture film
 25 for editing PAL
(European
standard)
 29.97 for editing
NTSC (North
American standard)
video (television)
Specifying Project Settings


Frame rate indicates to the
number of frames per second
contained in the source or the
exported video. Whenever
possible, the timebase and
frame rate agree. The frame
rate does not affect the speed
of the video, only how
smoothly it displays.
Timecode is a way of
specifying time. Timecode is
displayed in hours, minutes,
second and frames
(00;00;00;00). The timecode
number gives each frame a
unique address.
Specifying Project Settings

Frame size specifies the dimensions (in pixels) for
frames. Choose the frame size that matches your
source video. Common frames sizes include:
 640 x 480–standard for low-end video cards
 720 x 486–standard-resolution professional video
 720 x 480–DV standard
 720 x 576–PAL video standard (Used in Europe.)
Specifying Project Settings

Aspect ratio is the ratio of width
to height of the video display.



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Pixel aspect ratio is the ratio for a pixel
while the frame aspect ratio is the
width to height relationship for an
image.
4:3 is the standard for conventional
television and analog video.
16:9 is the motion picture standard.
Distortion can occur when a source
image has a different pixel aspect ratio
from the one used by your display
monitor. Some software may correct
for the distortion.
Specifying Project Settings

CODECs (compressor/decompressor) specify
the compression system used for reducing
the size of digital files. Digital video and
audio files are very large and must be
reduced for use on anything other than
powerful computer systems. Some common
CODECS include systems for QuickTime or
Windows.
Specifying Project Settings


QuickTime (movie-playing
format for both the Mac
and Windows platform) Cinepak, DV-NTSC, Motion
JPEG A and B, Video
Video for Windows
(movie-playing format
available only for the
Windows platform) –
Cinepak, Intel Indeo,
Microrsoft DV, Microsoft
Video1
Specifying Project Settings

Color bit depth is the number of colors to be
included. The more colors that you choose to
work with, the larger the file size and in turn, the
more computer resources required.


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8-bit color (256 colors) might be used for displays on the
Web.
24-bit color (millions of colors) produces the best image
quality.
32-bit color (millions of colors) allows the use of an alpha
channel .
Specifying Project Settings


Audio bit depth is the
number of bits used to
describe the audio
sample.
 8-bit mono is similar to
FM radio
 16-bit is similar to CD
audio
Audio interleave
specifies how often audio
information is inserted
among the video frames.
Specifying Project Settings


Audio compression
reduces file size and is
needed when you plan
to export very large
audio files to CDROMs or the Internet.
Audio formats include
WAV, MP3, and MIDI
files. MIDI files do not
include vocals. MPEG
files can also include
audio.
The Editing Process

Visual and audio source media are referred to as
clips, which is a film industry metaphor referring
to short segments of a film project.
 Clips may be either computer-generated or
live-action images or sounds that may last
from a few frames to several minutes.
 Bins are used store and organize clips in a
small screen space. Bin is another film
industry metaphor, which is where editors
hung strips of film until added to the total
production.
Premiere UI
Editing Tools

Opening and viewing clips
 Images must be in a format that the video
editing software can recognize such as an avi
(for animation), wav (for sound), or jpg (for still
image) before it can be imported.
 Many software programs provide both a
“source” window and a separate “program”
window where the entire production can be
monitored.
 Sound clips may be displayed as a waveform
where sounds are shown as spikes in a graph.
Editing Tools


Playback controls are a part of most viewing
windows. Play, Stop, Frame back, frame forward
are typical of window commands.
The Timeline helps cue the user as to the
relative position and duration of a particular clip
(or frame) within the program by graphically
showing the clips as colored bars whose length is
an indication of the duration. As clip positions
are moved along the timeline, their position
within the program is changed.
Editing Tools


Typically the timeline will include rows or
individual tracks for images, audio, and scene
transition clips. The tracks often include a time
ruler for measurement of the clips duration.
Some programs allow the duration of a clip to be
changed by altering the length of the bar
representing the clip. Scenes within the
program may be slowed or the speed increased
using this stretch method.
Editing Tools

Cutting and joining clips
 Software tools are typically
available for selecting a clip
on the timeline and then
cutting the bar that
represents the clip. Using
this process, segments of
“film” may be separated,
deleted, moved, or joined
with other clips.
 Cutting and joining may be
used on audio or video.
Editing Tools

Transitions allow you to make a
gradual or interesting change from
one clip to another by using special
effects.
 Transitions might include
dissolve, page peels, slides, and
stretches.
 The number and types of
transitions available depend upon
the software you are using.
Audio mixing is the process of
making adjustments to sound
clips.
Editing Tools

Title clips
 Alpha channel
allows you
superimpose the
title
 Title rolls allow
text to move from
the bottom of the
screen to beyond
the top used for
credits.
Editing Tools


A title crawl moves the text
horizontally across the
screen. News bulletins along
the bottom of the television
are an example of this type
of effect.
Text and graphics may be
created in other programs
and inserted. Video editing
programs are usually limited
in their ability to create and
manipulate text and
graphics.
Editing Tools

By using layering techniques, adjusting opacity,
and creating transparency, composite clips can
be created.
 Bluescreen (greenscreen) and track
hierarchy allow background scenes to be
overlaid and image editing to occur.
 Keying makes only certain parts of a clip
transparent which can then be filled with other
images (clips on the lower tracks of the
timeline.)
Creating Output

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Output may be to
videotape for display
on a television or to a
digital file for display
through a computer
output device.
Output may be put
into other
presentation programs
such as PowerPoint.
Creating Output

Export goals will determine the
output settings that you choose.
 Does the production need to
operate on Windows and/or Mac
platforms?
 What software will be used to
play your production?
 What image quality is required?
 How big can the file size be?
 Will the production be displayed
on the Web?
Creating Output


Common digital outputs
 Audio Video Interleave (avi) – for use on
Windows only computers, good for short
digital movies.
 QuickTime – a cross platform Apple format
that is popular for Web video.
 RealVideo – RealNetworks streaming video
is an extremely popular format.
Video editing programs may be exported to
other multimedia programs (such as
Macromedia Director or Authorware) for
addition editing or integration with other
materials such as Flash programs.