This document discusses various methods for compressing animation files, including reducing aspect ratio, frame rate, and using codecs. It describes lossless compression, which preserves quality, and lossy compression, which achieves higher compression ratios but can reduce quality. Common compression formats discussed include MPEG, QuickTime, SWF, AVI, and GIF.
2. Concept of Compression
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4.2
There are several methods can be implemented to
compress animation, such as;
Reducing aspect ratio; eg. from 640 x 480 to 320 x 240.
Reducing frame rate; eg. from 30 fps to 15 fps.
3. CODEC
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4.3
Compression/Decompression algorithm
(CODEC) has been developed to reduce the file size
and enables animation to be stored in one storage
media, such as CD or hard disk.
A codec is software that is used to compress or
decompress a digital media file, such as a song or
video.
4. CODEC
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4.4
In general, CODEC runs compression and
decompression of data, where data will be
compressed into smaller packets so that it can be
stored and distributed easily.
Compression replaces pixels with mathematical instructions,
resulting much smaller size of file.
Decompression decodes the mathematical instruction back
into pixels.
5. Data Compression
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4.5
Example of data compression software:
7 ZIP, Advance Comp, Bzip2, File Roller, Gzip, P7zip,
PNGOUT, Pngcrush, Zlib, Winrar, Winzip,
Sensor TRANSMISSION Reconstructed
Data Data
Compressed Compressed
Data Data
Compressor Decompressor
Storage
6. Lossy and Lossless
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4.6
Lossless
Lossless compression enables user to compress the size of
animation without affecting the quality.
Resulting much smaller compression ratio.
Uses Run Length Encoding
E.g:
WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWW
WWWWWWWWWWWWWWWWWWWWWBWWWWWWWW
WWWWWW
=12W 1B 12W 3B 24W 1B 14W
7. Run Length Encoding
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4.7
7 4 2 7 3
Compression in Run Length Encoding
ABBBBBBBBBCDEEEEF
Using RLE compression, the compressed file takes up 10 bytes and
could look like this:
A *8B C D *4E F
8. Lossy and Lossless
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4.8
Lossy
Lossy compression can reduce the size of file smaller than
lossless compression.
Resulting much larger compression ratio.
Erasing some bit data may result low quality display in
animation.
Eg: JPEG
Original Image High compression
(lossless PNG, 60.1 (98% less
KB size) — information than
uncompressed is uncompressed
108.5 KB PNG, 1.14 KB
9. Compression/Decompression Standard
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4.9
Motion Picture Expert Group (MPEG)
MPEG use asymmetric algorithm where the mathematical
instructions will determine data for each frames.
MPEG will only recording location and moving object only,
while static images will be recorded once and be used over and
over again.
10. Compression/Decompression Standard
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4.10
Cinepak
Using vector algorithm compression where it enables video
clip or animation be played at a fast rate.
Cinepak is a QuickTime software
11. Compression/Decompression Standard
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4.11
Apple’s QuickTime
Using lossy compression, it can produce compression at a ratio
5:1 up to 25:1.
Advantages:
Plug-in for QuickTime (known as QuickTime Players) distributed
free of charge.
Does not require special equipment for playback or distribution.
Disadvantages:
Small display area.
Requires large RAM and hard disk because of its large size of file.
12. Compression/Decompression Standard
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4.12
SWF - Shockwave Flash
Advantage : File size is small for a complex
animation
DCR – Interactive in nature
Developed by Macromedia Director
Used for distribution through web, due to its
file size
13. Compression/Decompression Standard
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4.13
MOV –
Use to distribute animation file in video format
Advantages :
cross platform
good quality of audio and video
presentation
AVI - Audio Video Interleave
distributing animation file in video format
quality of presentation is less compared to MOV
14. Compression/Decompression Standard
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4.14
MPEG - to set standards for audio and video
compression and transmission
Have several levels of functionality:
MPEG-1: Initial video and audio compression standard, used
as the standard for Video CD and Layer 3 (MP3) audio
compression format
MPEG-2: video and audio standards for broadcast quality
television. Used for digital television, digital satellite TV
services, digital signals, and for DVD video discs.
15. Compression/Decompression Standard
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4.15
MPEG-4: Expands MPEG-1 to support video, audio or 3D
content.
MPEG-7: A formal system for describing multimedia content.
16. Compression/Decompression Standard
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4.16
GIF
Factors that make GIF most commonly used:
Support transparency to image.
Animation played non-stop.
Cross-platform.
Doesn’t require any kind of plug-in.
Disadvantages:
Not supporting audio file format.
No interactivity.
Only 256 colors.