Media Assets Outcome 1
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Contents
Identifying Media Assets ............................................................................................ 4
Graphical Assets ........................................................................................................ 5
Sprites .................................................................................................................... 5
Billboarding ............................................................................................................. 5
Skyboxes ................................................................................................................ 6
Advanced Skybox ............................................................................................... 7
Bitmap Images ........................................................................................................ 7
Vector Images......................................................................................................... 8
Textures ................................................................................................................ 10
Video File Formats................................................................................................ 11
3g2 .................................................................................................................... 11
3gp .................................................................................................................... 11
asf ..................................................................................................................... 11
asx .................................................................................................................... 12
avi ..................................................................................................................... 12
flv ...................................................................................................................... 12
mov ................................................................................................................... 12
wmv................................................................................................................... 12
mpeg ................................................................................................................. 13
divx.................................................................................................................... 13
Video Capture Methods ........................................................................................ 13
Traditional Animation ............................................................................................ 14
Stop frame Animation ........................................................................................... 15
Computer Animation ............................................................................................. 16
Audio ........................................................................................................................ 19
Audio Asset Types ................................................................................................... 19
Audio File Types ................................................................................................... 20
aiff ..................................................................................................................... 20
iff ....................................................................................................................... 21
ra ....................................................................................................................... 23
wav.................................................................................................................... 23
aa ...................................................................................................................... 24
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acm ................................................................................................................... 25
Audio Asset Acquisition ........................................................................................ 25
Editing Audio Files ................................................................................................ 26
Methods of Capturing Text ................................................................................... 27
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Introduction (L4, L5, L6)
This document contains the on-line content for Learning Outcome One of Media
Assets. The brackets at the right-hand-side of each section title you will see the
level for which the material is written. However, don’t be constrained. If you are
studying at a lower level, level 4 or 5, and what to enhance your knowledge by also
reading material written for a higher level, please feel free to do so. There is nothing
wrong with aiming for excellence.
What Are Media Assets? (L4, L5, L6)
The term ‘media asset’ was first used in the games industry to describe individual
pieces of digital media, such as the character graphics, music and sound effects,
which are used in the creation of a large project or production, such as the game
itself.
Generally speaking an “asset” is anything that can be owned or controlled to produce
value and that is said to have positive economic value.
Media assets are the
graphics, videos, audio, animations maps, and other artistic data that go into media,
particularly interactive media such as video games.
Clearly, to a games developer
these all have economic value as they may have taken a considerable amount of
time, effort and resources to generate.
Identifying Media Assets (L4, L5, L6)
Throughout the materials we will look at various types of media assets and you will
become familiar with the types of graphics, video and audio files that make up a
computer game. You should be able to play a game and look at the graphics in use,
whether the character sprites or the backgrounds and listen to the audio clips which
enhance the overall game play. There are 3 main ways in which media assets come
to be, they can be sourced, captured or created.
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Graphical Assets
Graphics assets can take a number of forms including sprites, skyboxes, vector and
bitmap images, and tiling textures.
Sprites (L4, L5, L6)
In computer games, a sprite is a 2D or 3D image or animation that is integrated into
a larger scene to become part of the game. It is most likely that you refer to these
sprites as ‘graphics’ and they are frequently the playable characters within the game.
The most common sprites are those of characters and these can be easily and
legally sourced on the internet.
To understand what sprite sheets are you need to think back to simple animations
created using flip books. When you flip rapidly thoroughly the pages of the book the
illusion of movement is created. These individual images can be used to create
movement but the creation of a sprite sheet is a more efficient method of animation.
This allows you to create one image file that contains all of the images. The images
in a sprite sheet are organised in rows and columns.
Billboarding (L5, L6)
Billboarding is a term used to describe the use of sprites in a 3D environment. A 3D
sprite always faces the camera in the same way that a billboard is positioned by the
roadside to face oncoming drivers.
Using billboarding has two main advantages:
1. Performance – 3D sprites can be rendered more quickly, so this can speed
the game up.
2. Aesthetic (artistic) – sprite based images can provide more realistic effects
such as fire, smoke, water, etc.
From the camera the sprite plane is always perpendicular (at right angles). Images
can be scaled (increased or decreased in size) to make them appear closer or
further away, this is known as perspective. In the game “The Legend of Zelda: The
Wind Waker”, tufts of grass and puffs of brown smoke are integrated as sprites.
A
close look at individual scenes reveals that some of the blades of grass reveal their
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geometry, with some blades of grass appearing closer to the camera than the
flowers. Watch the trailer and see if you can spot the billboarding imperfections.
These imperfections escape the notice of most gamers because they are rare, and
often do not last very long as they and the camera move.
This suggests that sprites create an effective illusion when:

The sprite exists only for a short period of time

The animation is constantly changing or appears to be rotating

The object has a similar appearance from common viewing angles such as a
sphere or a cube

The image inside the sprite already depicts a three dimensional object

The viewer accepts that the object only has one perspective. (such as small
plants or leaves)
Don’t confuse sprites with pixel art. Pixel art is low resolution 2D graphics drawn on
a computer. Pixel art is created for many purposes other than as a sprite including
icons, display art, textures video game backgrounds and T-shirts. Due to advances
in computer hardware pixel art sprites are not popular outside of handheld game
systems and mobile phones.
Have a look at the following website which gives
greater insight into pixel art:
http://indiegames.com/2008/02/tutorial-creating-pixel-art-with-photoshoppixeljam.html
Skyboxes (L5, L6)
A skybox is usually a box or sphere surrounding a level or map textured with a
background image to make the level look larger than it actually is. When creating a
skybox the sky, distant mountains, distant buildings, and other unreachable objects
are enclosed in a cuboid and the objects contained in it are onto the cube's faces
(using a technique called cube mapping). By careful alignment, a viewer in the exact
middle of the skybox will perceive the illusion of a real 3D world around it, made up
of the cuboids six faces.
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As a viewer moves through a 3D scene, it is common for the skybox to remain
stationary. Since the objects in the scene appear to move, while the skybox does
not this creates the illusion that the skybox is very far away giving the impression of
real life.
A skydome employs the same concept but uses either a sphere or a hemisphere
instead of a cube. See the video at http://www.3dmotive.com/training/free/creatinga-skydome/?follow=true on the use of a skydome.
Advanced Skybox (L6)
The standard skybox has some disadvantages and designers have worked to
produce newer engines which allow the skybox to move along with the player,
although at a different speed. As depth is perceived by comparing the movement of
objects, making the skybox move slower than the level causes the skybox to appear
far away.
It is also possible to include 3D geometry which will surround the playing
environment, such as unreachable buildings or mountains. These are rendered at
1/16 scale, and then resized to appear much larger.
This effect is called "3D
skybox".
Bitmap Images (L4, L5, L6)
Bitmaps are used to create graphics which look realistic and images including
photographs, graphics with lots of colours and graphics with special effects, such as
buttons with drop shadows. Bitmaps are widely supported and have lots of different
formats. The most common bitmap file formats are:

jpeg (Joint Photographic Experts Group)

gif (Graphic Interchange Format)

bmp (a format developed by IBM}

png (Portable Network Graphics)

tiff (Tagged Image File Format)
Bitmap graphics consist of small rectangular pixel elements or pixels which when
viewed displayed at an appropriate resolution merge to produce the impression of
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continuous tones. Each pixel consists of a number of bits that determines the colour
or bit depth setting. The greater the number of bits per pixel the better the quality of
the graphic but the bigger file size. The bit depth available depends on the graphics
card and software being used. Typical bit depths are 8, 16, 24, 32 and 48 bits per
pixel.
Bitmaps are resolution dependant. If the resolution is too low then the pixels may
become evident. This is known as pixilation.
All scanned images and images from digital cameras are bitmaps. You can also
create a bitmapped image with packages like Adobe Photoshop, Corel Paint Shop
Pro (PSP), Corel Painter and Adobe Fireworks. Photoshop and Paint Shop Pro are
both aimed at the Professional market and have much in common.
Adobe Fireworks is a combination of an image editor, bitmap creation and vector
drawing package. This was originally developed for web developers and designers,
to take away the need to have a separate vector package and bitmap package.
Vector Images (L5, L6)
Vectors don't consist of pixels. Instead, they are made up of co-ordinates, shapes,
line, and colour data. Vector graphic files are smaller than bitmap files because they
need to store only the information necessary to draw the object. For example the
only information that needs to be stored in order to draw a circle is the radius, the
location of the centre of the circle, stroke line style and colour and the fill style and
colour.
Vectors are used to create graphics such as banners, buttons, text, line art and
detailed drawings (plans, maps). Effects can be added to vector by rasterising them
(converting them to bitmaps) and then editing them in a package like Adobe
Photoshop.
Drawing packages come with ready-made shapes such as, squares, circles, and
curves that can be combined into graphics.
interesting and complex graphics.
Curves are needed to make more
Bézier curves are defined by mathematical
equations - essentially, the coordinates of a curve can be calculated and drawn by
knowing the position of two end points and two control points.
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Paths are the basis for all vector objects and are made up from one or more line
sections connected by two or more anchor points and may be open or closed.
Handles are special points placed around an active object used to manipulate the
object when clicked and dragged with the mouse or other pointing device.
Handles are used to modify the shape of a curve while the anchor points changes
the direction and depth of the curve.
Paths can also be used to change the layout and direction of text, from straight lines
to sit on curves and corners. This is known as text on a path.
Common uncompressed formats include AI (Adobe Illustrator), FH (Adobe
Freehand) and CDR (Corel Draw). All three formats are fully supported by Windows
and Mac operating systems.
Vector Graphics packages include Adobe Illustrator, CorelDraw, Flash, GIMP and
Adobe Fireworks. Illustrator is a professional vector graphics editor developed and
marketed by Adobe Systems and is functionally similar to its main competitors,
CorelDraw and Macromedia FreeHand. Adobe Flash is a multimedia platform used
to add animation, video, and interactivity to web pages but is often used for games
also.
Adobe Fireworks is a combination of an image editor, bitmap creation and
vector drawing package.
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Textures (L4, L5, L6)
Textures define what objects will look like, the surface appearance or skin. This
gives a more realistic appearance to surfaces such as stone walls, wooden tables,
corridors etc. Creating realistic textures and creating tiles is a fundamental gamemaking skill. If the textures that you apply to the objects in your game don’t look
right then the objects themselves won’t look convincing.
Textures have a look and feel. Textures exist all around us: wallpapers, wooden
desks, blankets all have a distinctive look and feel.
If you were texturing an attack
helicopter in a war game you wouldn’t use a wood-like texture for its skin. However,
getting the right texture is only a part of the story. You have to change it into a tile
that will be placed neatly onto the surface of the helicopter.
Tiles are textures that have been specially formatted to blend together well in the
video game world.
This is done using one of image manipulation programs
mentioned above.
In order to cover a surface it is necessary to repeat it over a larger surface. It just
looks like eight identical tiles side-by-side, which is exactly what it is. OK for the
bathroom but not for a game. To make something less obviously a set of tiles we
could take our original tile and divide it into four segments and then rearrange them
according to the pattern.
There is still a repetition of the pattern, but it no longer looks like eight identical
blocks placed side by side.
To round off you could use something like Photoshop
or Corel Paint Shop Pro to make sure the areas in the middle look good by removing
anything that looks unreal.
128 x 128 or 256 x 256 pixels are good sizes for tiles because they are ideally suited
for the computer and it will handle these graphics very efficiently. Using a size like
100 x 100 pixels could slow the game down.
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Videos
A video is a moving image file in a format that is compatible with the game
development environment.
Video File Formats (L4, L5, L6)
There are quite literally hundreds of video file formats. To get an idea of just how
many video file formats there are visit http://www.fileinfo.com/filetypes/video. You
will notice however that only a few are very popular including: 3g2, 3gp, asf, asx, avi,
flv, mov, and wmv.
Others like mpeg, divx, and .m2p are less popular but still
common, while formats like m4e, mmv and mp2v are quite rare.
3g2
3g2 is an audio/visual format designed for transmitting multimedia files over the
Internet.
It is essentially an updated version of the 3gp format used by mobile
phones for saving video over the Internet. It is widely supported on the Mac, Linux
and Windows platforms.
3gp
Like 3g2, 3gp was developed by the 3GP Partnership.
It was designed for
transmitting audio and video files between 3G mobile phones and over the Internet;
commonly used by mobile phones that support video capture. Like 3g2, 3gp is
widely supported.
asf
The Advanced Systems Format (.asf) was developed by Microsoft as a proprietary
video and audio container format for streaming media. It contains audio and video
data and optionally metadata, such as title, author, and copyright bibliographic data.
asf files are used to specify the structure of the video stream, but not the encoding
method. They frequently contain Windows Media Video (wmv) or Windows Media
Audio (wma) data. They can be compressed using a variety of video codecs. asf is
widely supported on the Windows platform but not so widely on a Mac or by Linux.
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asx
asx files typically reference a URL that points to the location of the actual media file.
asx can be used to create audio or video playlists.
It is a popular format more
widely supported on Windows that the Mac or by Linux.
avi
The Audio Video Interleave (avi) format was created by Microsoft as a wrapper
format to store video data encoded in a variety of codecs. Typically avi files cannot
be compressed as much as mpeg or mov files. avi files can be played by various
video players, but the player must support the codec used to encode the video data.
flv
Flash Video (flv) files are Flash-compatible video files consisting of a short header,
interleaved audio, video, and metadata packets. .flv files are exported by the Flash
Video Exporter plug-in included with Adobe Flash. However, the .flv format is an
open format that is also supported by non-Adobe applications with .flv file support.
.flv files may be exported from QuickTime Pro or other applications capable of
exporting export to the QuickTime file format. Given the enormous popularity of
Adobe Flash this is a very widely supported format.
mov
Apple QuickTime Movie (mov) file format is a common multimedia format often used
for saving movies and other video files.
The mov format uses a proprietary
compression algorithm developed by Apple and is compatible with both Macintosh
and Windows platforms.
wmv
The Windows Media Video File (wmv) is a video file based upon the Microsoft
Advanced Systems Format (asf) container format and compressed with Windows
Media compression.
Microsoft Windows Media Player 9 was the last version of the Windows Media
Player developed for Mac OS X. However, Mac users can use Flip4Mac WMV to
play wmv files. The wmv format is not supported by Linux.
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mpeg
The mpeg Movie format is a popular video format standardized by the Moving
Picture Experts Group (MPEG). mpegs are compressed using mpeg-1 or mpeg-2
compression and are often used for creating movies that are distributed over the
Internet. mpeg movies are typically saved with an .mpg extension. mpegs are not
supported on a Linux platform.
divx
divx-encoded movie files are high-quality, high-compression video codecs used for
digital video distribution. Videos are compressed to a fraction of the original size
with minimal loss in quality supporting resolutions of up to 1080 HD. The divx format
is recognized by several software video playback programs as well as some DVD
players and other consumer electronics.
Video Capture Methods (L5, L6)
Video capture is the process of converting an analogue video signal from something
like a video camera or DVD player—to digital form. The resulting digital data are
referred to as a digital video stream. Video capture involves three steps:
1.
The analogue video signal is digitised to produce a raw digital data stream
2.
The chrominance is demodulated to produce colour difference video data
3.
The data is transformed by a colour space converter to generate data
conforming with any one several colour space standards including RGB and
YCbCr
A Video Capture Card and TV Capture Card allow you to send a Video or TV signal
to your Computer. The signal can then be recorded to the Computer’s Hard Drive
with TV or Video Capture Software.
Video capture software will typically have some or all the following features:

Capture video directly to your hard drive

Record video in many video file formats including avi, wmv, flv, mpg, 3gp,
mp4, mov and more
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
Capture video from a webcam, network IP camera or a video input device
(e.g., VHS recorder)

Screen capture software records the entire screen, a single window or any
selected portion

Digital zoom with the mouse scroll wheel, and drag to scroll the recording
window

Zoom-to-mouse feature focuses the recording window on the cursor

Mouse highlighting spotlights the location of the cursor

Record video alone or video and audio simultaneously

Record audio from your microphone and speakers simultaneously, ideal for
recording video conferences

Time lapse video recording

Create photo snapshots of a video at any time

Add your own text captions or time stamp your video

Change colour settings and video effects before recording

Adjust the video resolution, size and frame rate for capture

Ability to burn directly to DVD
Animations (L4, L5, L6)
Animation is the rapid display of a sequence of still 2-D or 3-D images or model
positions in order to create an illusion of movement. The effect is an optical illusion
of motion due to the phenomenon of persistence of vision, which is the phenomenon
of the eye by which an afterimage is thought to persist for approximately one twentyfifth of a second on the retina.
Traditional Animation (L4, L5, L6)
Traditional or cel animation involves making drawings each of which are slightly
different from each other and then tracing or photocopying them onto transparent
acetate sheets called cels. The images are then painted on the side opposite the
line drawings. The completed cels were then photographed one by one onto cine
film using a rostrum camera.
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Today, an animator’s drawings are either scanned into or drawn directly into a
computer system.
From there they are transferred to 35 mm film or digital video.
Because the look and feel of traditional cel animation is still preserved the process is
sometimes referred to as "tradigital".
Full animation refers to the process of producing high-quality traditionally animated
films, which regularly use detailed drawings and plausible movement.
Limited
animation involves the use of less detailed and/or more stylized drawings and
methods of movement.
Rotoscoping is a technique where animators trace live-
action movement, frame by frame. The source film can be directly copied from
actors' outlines into animated drawings. Live-action/animation is a technique, when
combining hand-drawn characters into live action shots.
Stop frame Animation
A stop frame animator physically manipulates real-world objects and photographing
them one frame of film at a time to create the illusion of movement and there is a
wide range of computer software available to do this type of animation. The different
types of stop frame animation are named after the type of media used to create the
animation.
Puppet animation typically involves stop-motion puppet figures interacting with each
other in a constructed environment, in contrast to the real-world interaction in model
animation.
Rather than manipulating one existing puppet puppetoons, use a
different version of a puppet for different frames.
Clay, or plasticine animation often abbreviated as claymation, uses figures made of
clay, plasticine or a similar malleable material to create stop-motion animation. An
award winning exponent of this type of animation is Nick Park’s Wallace & Gromit.
Cutout animation is produced by moving 2-dimensional pieces of material such as
paper or cloth.
Terry Gilliam's animated sequence from Monty Python's Flying
Circus is a good example. A variation of cut out animation is Silhouette animation in
which the characters are backlit and only visible as silhouettes.
Model animation refers to stop-motion animation created to interact with and exist as
a part of a live-action world. A variant of model animation, Go motion uses various
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techniques to create motion blur between frames of film, which is not present in
traditional stop-motion.
Object animation uses ordinary inanimate objects in stop-motion animation.
A
variation called Graphic animation uses non-drawn flat visual graphic materials such
as photographs, newspaper clippings, and magazines. Sometimes the objects are
moved past the stop-motion camera. Sometimes the graphics remain stationary,
while the stop-motion is moved to create on-screen action.
Pixilation is a technique that uses human beings as stop motion characters.
Computer Animation (L5, L6)
Many sorts of animation can be integrated into a computer game. The distinctive
factor of computer animation is that the animation is created digitally on a computer.
2D animation figures are created and/or edited using 2D bitmap graphics or vector
graphics packages. This includes computerized versions of traditional animation
techniques such as tweening, morphing, and onion skinning.
Tweening is the process of generating intermediate frames between two images to
give the appearance that the first image evolves smoothly into the second image to
create the illusion of motion.
Morphing is a special effect that is used in
animations to change one image into another through a seamless transition. Onion
skinning is a technique that an editor can use to view several frames at once so they
can decide how to create or change an image based on the previous image in the
sequence. Adobe Flash is a typical 2D animation package.
In contrast to 2D computer graphics 3D graphics use three-dimensional
representations of geometric data. In spite of this 3D computer graphics rely on
many of the same algorithms as 2D computer vector graphics in the wire-frame
model and 2D computer raster graphics in the final rendered display. In fact, 2D
applications may use 3D techniques to achieve effects such as lighting, and 3D
applications may use 2D rendering techniques. However, there are differences. A
3D model is the mathematical representation of any three-dimensional object, which
can be displayed visually as a two-dimensional image through a process called 3D
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rendering. The process of creating 3D computer graphics can be divided into three
basic stages: 3D modelling, layout and animation, and 3D rendering.
3D modelling describes the process of forming the shape of an object.
The
commonest sources for 3D models are those created by an artist or engineer using
3D modelling application or those scanned into a computer from real-world objects.
Layout and animation describes the placement and the movement of an object within
a scene. The layout determines the spatial relationships between objects in a scene.
Automation refers to how an object moves over time. Popular methods include
keyframing, inverse kinematics, and motion capture.
Keyframes are drawings that define the starting and ending points of any smooth
transition. A sequence of keyframes defines which movement the viewer will see.
The position of the keyframes determines the timing of the movement. Because only
two or three keyframes over the span of a second do not create the illusion of
movement, the remaining frames are filled with in-betweens, a process known as
“tweening”.
Next Section (L6)
Inverse kinematics calculates the motions necessary to achieve a desired position.
For example, what are the motions required to make it look like an animated
character is picking up an object? This is more complex than just moving an object
from one position to another.
It involves the translation and rotation of a series of
interconnected objects while observing limitations to the range of motions that are
physically possible. For example, an animation would look unrealistic if a character's
hand moved through its body to pick up an object located behind it. The skilful use
of kinematics can involve the application of knowledge as diverse as anatomy,
physics and engineering.
Motion capture is the term used to describe the process of recording movement and
translating that movement onto a digital model. In 3D computer animation, it can be
applied to recording actions of human actors, and using that information to animate
digital character models.
When it includes face and fingers or captures subtle
expressions, it is often referred to as performance capture. Motion capture has a
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number of advantages over traditional 3D animation methods and some
disadvantages.
Advantages include: the amount of animation data that can be
produced within a given time is extremely large when compared to traditional
animation techniques, which contributes to both cost effectiveness and meeting
production deadlines; and complex movement and realistic physical interactions.
such as secondary motions, weight and exchange of forces can be easily recreated
in a physically accurate manner. Disadvantages include: the cost of the software,
equipment and personnel required can potentially be prohibitive for small
productions, and movement that does not follow the laws of physics generally cannot
be captured.
3D Rendering converts a model into an image either by simulating light transport to
get photorealistic images, or by applying some kind of style as in non-photorealistic
rendering. Light transport theory deals with the mathematics behind calculating the
energy transfers between media that affect visibility.
Modelling inverse light
transport enables reasoning about shadows and inter-reflections two major unsolved
problems in computer vision and can greatly expand the applicability of a host of
computer vision techniques, i.e., photometric stereo, shape from shading, BRDF
measurement, etc.
Non-photorealistic rendering (NPR) is an area of computer graphics that focuses on
enabling a wide variety of expressive styles for digital art including painting,
drawing, technical illustration, and animated cartoons and is common in video
games. In many cases, the geometry of the model is unchanged only the material
applied to the surface is modified. Most of the techniques applied to 3D geometry
are intended to make the scene appear two-dimensional. Well-made 3D animations
can be difficult to distinguish from live action.
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Audio (L4, L5, L6)
Some games don’t really need sound, for example simple graphical games like
Snood or Solitaire. In fact sound could be annoying and intrusive in this type of
game. However, some games need sound and without sound would be like a film
without its sound track. For example, the ominous ambient sounds of Resident Evil,
that compounds the tension and horror as the relentless zombies, destroy your
Alpha Team comrades.
Audio Asset Types (L4, L5, L6)
An audio asset can be any type of sound played in a game.
This can include
speech, music, and sound effects made by the movement and interaction of objects
such as a passing car or an overflying aircraft.
Sound assets can be straight-
forward recordings (capture) of real people and real objects or where necessary
synthesised using computer software.
The recording can then, if necessary be
modified by adding echo, changing the pitch or speed, amplifying it or changing the
tempo. However the audio asset is created it must be appropriate to the action and
sound convincing.
Speech can be obtained by recording a person reading a script, however, the skilful
use of an audio editing suite can be used to add an echo or distort the voice for
example to make it sound metallic or mechanical as befitting a robot for example.
Another example would be if a character spoke in a large subterranean cavern a
dead acoustic wouldn’t sound convincing because you would expect an echo.
As with film and television music is often the forgotten element in video game design.
This is possibly because sound effects are more subtle than glitzy visual effects and
work on the listener’s subconscious to draw them inexorably into the game world.
However, in 2000 the National Academy of Recording Arts and Sciences (NARAS)
recognised the importance of video game scores by allowing interactive games to
compete in the annual Grammy Awards.
The sound effects created by the interaction of objects in a game are also very
important.
In the game “Medal of Honor” you would expect to hear the sound of
gunfire and explosions. If a character fires a heavy machine gun it needs to sound
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Media Assets Outcome 1
like a heavy machine gun and not like an air rifle.
In the same way that the
movement of objects in a game have to obey the rules of physics, unless specifically
required not to do so, sound effects have to obey the rules of acoustics, which is why
the sound for a video game is created and edited by specialist sound engineers.
Audio File Types (L5, L6)
As with video files there are a large number of audio file types ranging from those
that are very common to those that are rarely seen. Among the most common audio
file formats are aif, iff, mp3, mpa, ra and wav. Other common formats are aa, acm,
and cda. Other formats such as the .box and imf formats are rarely seen. To get an
idea
of
just
how
many
audio
formats
there
are
visit
http://www.fileinfo.com/filetypes/audio
aiff
The audio file interchange format (aiff) was developed by Apple Computers from the
Electronic Arts' .iff format. This type of file supports uncompressed CD-quality audio
and is typically used to store standard CD audio. Standard aiff files are 16-bit, twin
channel files using a sampling rate of 44.1 KHz. aiff files typically have an .aif
extension but can also have an .aiff extension as well. aiff files are not supported by
Linux.
File
Operating System
Application(s)
Mac OS
Apple Quick Time Player
format
.aif (.aiff)
Apple iTunes
Roxio Toast 11
Apple GarageBand
Coq
Windows
Nullsoft Winamp Media Player 5.6
Apple Quick Time Player
Apple iTunes
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Media Assets Outcome 1
Microsoft Windows Media Player
Roxio Creator 2011
iff
The Interchange File Format (iff) was created by Electronic Arts and may contain
image, text, or audio data. It is typically used for interchanging different types of data
across applications and platforms. It is widely supported and can be used as the
basis for several other file formats, including aiff.
An iff file consists of “chunks” which have four letter identifications. There are three
principle “chunks”: FORM, LIST and CAT each of which may contain text, numerical
data, or raw data. The FORM chunk specifies the format of the file, the LIST chunk
includes the properties of the file and the CAT chunk contains the rest of the data. iff
files used by The Sims and The Sims Online can be edited using IFF Snooper for the
Mac platform or IFF Pencil for Windows.
File
Operating System
Application(s)
Mac OS
Apple Quick Time Player
format
iff
IFF Snooper
Cloanto Amiga Forever
Linux
XnView
Cloanto Amiga Forever
Windows
Apple Quick Time Player
Coral PaintShop Photo Pro X3
ACD Systems Canvas 12
ACDSee Photo Manager 12
Cloanto Amiga Forever
XnView
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Media Assets Outcome 1
IrfanView
mp3
The Moving Picture Experts Group mp3 file format is a compressed audio format that
uses Layer 3 audio compression. The mp3 file format us typically used to store
music files and audio books on a computer’s hard drive providing near-CD quality
sound in a file approximately 1/10th the size of a aif or wav file.
The sound quality of an mp3 file depends upon the bit rate used for compression.
The higher the bit-rate the better the sound quality, but this comes at the expense of
a larger file size. Common bit rates are 128, 160, 192, and 256 kbps.
mp3 files are supported by most portable music players, such as the Apple iPod and
can also be played on the Amazon Kindle.
There is good support for mp3 files as
shown in the accompanying table.
File
Operating System
Application(s)
Mac OS
Apple iTunes
format
.mp3
VideoLAN VLC Media Player
Roxio Toast 11
Linux
VideoLAN VLC Media Player
XMMS
Amarok
Windows
Apple iTunes
Microsoft Windows Media Player
Xilisoft Video Converter Ultimate
Nullsoft Winamp Media Player 5.6
VideoLAN VLC Media Player
Roxio Creator 2011
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ra
The Real Audio .ra format is a common format for playing audio clips within a Web
browser. It uses a proprietary Real compression algorithm and can use various
codecs to compress audio with variable bit rates.
The .ra format is used by
RealPlayer, an audio and video streaming program and may be used to reference a
streaming audio file online or may contain audio data. It is supported by Mac OS,
Linux and Windows.
File
Operating System
Application(s)
Mac OS
RealNetworks RealPlayer
format
.mpa
VideoLAN VLC Media Player
Web browser with the RealPlayer plugin
Linux
RealNetworks RealPlayer
VideoLAN VLC Media Player
Web browser with the RealPlayer plugin
Windows
RealNetworks RealPlayer
J. River Media Center
VideoLAN VLC Media Player
Web browser with the RealPlayer plugin
wav
The wav format was developed by Microsoft and is a standard digital format for
storing waveform files and allows audio recordings to be saved with different
sampling rates and bit rates.
The wav format is similar to the aif file format but is
based upon the Resource Interchange File Format (RIFF), rather than the Audio
Interchange File Format (aiff). wav files are frequently saved as 44.1 KHz, 16-bit,
stereo files, which is the standard format used for CD audio.
wav files are typically seen on Windows-based computers, whereas .aif files are
more common on Macintosh systems.
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Media Assets Outcome 1
File format
Operating System
Application(s)
.wav
Mac OS
Apple iTunes
Apple QuickTime Player
Roxio Toast 11
RealNetworks RealPlayer
VideoLAN VLC Media Player
Linux
MMMS
VideoLAN VLC Media Player
Windows
Microsoft Windows Media Player
Apple iTunes
Apple QuickTime Player
Roxio Creator 2011
Nullsoft Winamp Media Player 5.6
Xilisoft Video Converter Ultimate
RealNetworks RealPlayer
VideoLAN VLC Media Player
aa
The Audible Audio Book File (aa) format is designed for storing spoken word audio
and supports chapter markers, bookmarks, etc., in the form of audio books. You can
convert aa files into mp3 files using programs such as SoundTaxi Media Suite,
Tunebite and TuneCab. Audible files are supported by the Apple iPod, Creative Zen,
SanDisk Sansa, various GPS devices, and the Amazon Kindle.
File
Operating System
Application(s)
format
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Media Assets Outcome 1
aa
Mac OS
Apple iTunes
Pocket PC
Audible AudiblePlayer
Windows
Audible AudibleManager
Apple iTunes
Nero Multimedia Suite 10
RapidSolution Tunebite 8
SoundTaxi Media Suite
TuneCab
acm
The Interplay Audio File (acm) file format developed by BioWare is a compressed
audio file used by Interplay video games, such as BioWare and Fallout.
Files
contain compressed audio stored in a proprietary format, which may be converted to
other audio file types, such as wav files.
It is supported only on the Windows
platform.
File
Operating System
Application(s)
Windows
Bioware Infinity Engine
format
acm
Nullsoft Winamp Media Player 5.6 with
ACM plugin
ACM/WAVC to WAV converter
Acm2wav
Audio Asset Acquisition (L4, L5, L6)
There are a variety of ways of capturing audio assets including by using
microphones, recording from a radio or TV programme, taking an extract from an
audio tape, CD or DVD, using a synthesiser, as downloads from the Internet or a
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Media Assets Outcome 1
combination of one or more of the above. When acquiring existing media assets be
very aware of possible copyright issues. Copyright is an issue we shall return to
later in the course.
Audio and music are awarded at the Video Games BAFTA’s every year and give you
an indication of their importance.
Editing Audio Files (L5, L6)
There are a variety of tools for editing audio files including Audacity, which is free
and WavePad Audio Editing Software Professional sound editing software which is
available as freeware or a feature richer version, which has to be purchased.
Functionality will typically have some of the following features:

Sound editing functions include cut, copy, paste, delete, insert, silence, and
Autotrim

Audio effects include, amplify, normalize, equaliser, envelope, reverb, echo,
and reverse

Should support a large number of audio and music file formats including mp3,
wav, vox, gsm, wma, au, aif, flac, real audio, ogg, aac, m4a, mid, amr and
many more

Should include spectral analysis (Fast Fourier Transform (FFT)), speech
synthesis (text-to-speech) and voice changer

Audio restoration features including noise reduction and click pop removal

Will support sample rates from 6 to 196kHz, stereo or mono, 8, 16, 24 or 32
bits

Have an easy to use interface
Text (L4, L5, L6)
Text media assets are required for the game to provide dialogue, create an
atmosphere and give player feedback or instructions. Common file types include
.doc, .docx, .log, .rtf, and .txt,
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.doc files are created and edited using Microsoft Word a word processing application
included with Microsoft Office. Microsoft Word 2007 and 2010 saves documents in
the OpenXML format with a .docx extension.
Microsoft Word Open XML file (.docx) files are created and edited using Microsoft
Word 2007 and later versions but may be opened with earlier versions of Word for
Mac and Windows via Open XML document support.
.docx documents are stored as a collection of separate files and folders in a
compressed zip package. .docx files contain XML files and three folders, docProps,
Word, and _rels, which hold the document properties, content, and relationships
between the files. You can manually open a .docx by renaming it to .zip file and then
decompressing the file with any zip decompression utility.
The .log, file format is used by a number of operating systems and is typically a text
file containing a time-stamped log of events. Log files are useful for keeping track on
what is happening while an application, in this case a game, is running.
To view
and edit .log files any plain text editor will do, for example Apple TextEdit on the Mac
and Notepad on a Windows platform.
The Rich Text File (.rtf) file format does not contain such a rich set of formatting
options as a Word Processed file such as a doc or docx file but does include some
formatting options such as several types of text formatting, such as bold type, italics,
different fonts and font sizes, and custom tab settings, and may also support images
saved within the text file.
A plain text (.txt) file format is a widely supported unformatted text file, which can be
recognised by any text editing or word processing program and by most other
software applications. Plain text files are also recognised by hardware devices, such
as smartphones and the Amazon Kindle.
Methods of Capturing Text (L4, L5, L6)
There are a number of ways in which text can be captured. The most obvious way is
to type it into a text editor or word processor. Another way of capturing text is by
using voice recognition software, which is now integrated into some desktop
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operating systems. The problem with voice recognition software is that it has to be
“taught” to recognise what the operator is saying. Careful proof-reading of text input
in this way is required as voice recognition software can make “mistakes”.
Text can be captured with a scanner either as a graphics file or with optical character
recognition (OCR) software, which will output the text to a text or word processor file.
As with voice recognition software careful proof reading is required.
There are now an increasing number of devices that will read and interpret
handwriting. As with voice recognition and OCR careful proof reading is a must.
Text can be captured directly from the screen. One way of doing this is to copy and
paste from a website.
Another way is to use a piece of software specifically
designed for screen capture and text capture/recognition. This can be useful in
situations where you need to save some data but were not able to do so because the
words or figures are a part of a graphic or picture. This type software is capable of
capturing and recognizing Web addresses (URLs) as well as the scanned blocks of
text without the need to use conventional expensive OCR programs.
The text is
selected using the mouse and copied to the clipboard from whence it can be output
to an application such as NotePad, WordPad, Word or OpenOffice. When capturing
existing text be careful not to infringe the copyright laws.
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