Page 189 - DCAP303_MULTIMEDIA_SYSTEMS

Unit 11: Compression

Huffman Coding notes
This is a little bit complicated than the previous one. First, the frequency of each appearing
character is taken. Then the characters that have least frequencies being taken to give values ‘1’
for the higher one and ‘0’ for the lower one and there wise it is continued. Then the each available
character is represented by a separated code included with 1s and 0s.
Lempel Ziv encoding
This system does the encoding as two processes. They are indexing and compressing a string
of symbols. When there is a set of characters, first step is to check whether an index have the
minimum available character combination that appears. If available then put the index number
in the string. If not, it will be added to the index. This compression technique is more effective as
it has a two way compression method.
Lossless Compression file formats
Audio
• Waveform Audio Format (WAF)
• Free Lossless Audio Codec (FLAC)
• Apple Lossless Audio Codec (ALAC)
• ATRAC Advanced Lossless
• Audio Lossless Coding
• MPEG-4 SLS
• Direct Stream Transfer (DST)
• DTS-HD Master Audio
• Meridian Lossless Packing (MLP)
• Monkey’s Audio APE
• RealPlayer—RealAudio Lossless
• Shorten—SHN,TTA—True Audio Lossless
• WMA Lossless
Graphics
• Adaptive Binary Optimization (ABO)
• JPEG XR
• Progressive Graphics File (PGF)
• Portable Network Graphics (PNG)
• Tagged Image File Format (TIFF)
Video
• Animation Codec
• CorePNG, Dirac
• FFV1
• JPEG 2000
• Huffyuv
• Lagarith
• MSU Lossless Video Codec
• SheerVideo
11.3.2 Lossy Compression algorithms

It is the compression technique which will lose data in the original source while trying to keep the
visible quality at the almost same amount. The compression ratio will be very high. Most probably

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