zlib is designed to be a free, general-purpose, legally unencumbered -- that is, not covered by any patents -- lossless data-compression library for use on virtually any computer hardware and operating system. The zlib data format is itself portable across
I ve written some many years ago dynamic Huffman algorithm to compress and decompress data. It is mainly targeted to data with some symbols occuring more often than the rest (e.g. having some data file consisted of 3 different symbols and their total number of occurence in that file s1(1000), s2(200), s3(30) so the total length of file is 1000+200+30=1230 bytes, it will be encoded assigning one bit to s1 and 2 bits to s2, s3 so the encoded length will be 1*1000+2*(200+30)=1460 bits=182 bytes). In the best case the file consisted of just one symbol will be encoded with compression ratio as 1:8. Huffman coding is used in image compression, however in JPEG2000 arithmetic codec is imployed.
EZW Embedded Zero-tree Wavelets Encoding,video codecs from the EZW family which use a 3D version of EZW or SPIHT algorithms showed better performance than the MPEG-2 compression algorithm. These algorithms have many advantages inherent for wavelet based schemes and EZW-like coders. Their most important advantages are good compression performance and scalability.
These three articles involves the combination of wavelet and MCTF. MCTF means motion-compensated-time-filter. It makes wavelet transform more popular because of the high compression efficiency.
A few short years ago, the applications for
video were somewhat confined—analog was
used for broadcast and cable television, VCRs,
set-top boxes, televisions and camcorders.
Since then, there has been a tremendous and
rapid conversion to digital video, mostly based
on the MPEG-2 video compression standard.
Today, in addition to the legacy DV,
MPEG-1 and MPEG-2 audio and video com-
pression standards, there are three new high-
performance video compression standards.
These new video codecs offer much higher
video compression for a given level of video
quality.
MPEG-2 has 7 distinct parts as well. The first part is the Systems section which defines the container format and the Transport Streams that are designed to carry the digital video and audio over ATSC and DVB. The Program Stream defines the container format for lossy compression on optical disks, DVDs and SVCDs.
H.264/AVC, the result of the collaboration between the ISO/IEC
Moving Picture Experts Group and the ITU-T Video Coding
Experts Group, is the latest standard for video coding. The goals
of this standardization effort were enhanced compression efficiency,
network friendly video representation for interactive
(video telephony) and non-interactive applications (broadcast,
streaming, storage, video on demand). H.264/AVC provides
gains in compression efficiency of up to 50％ over a wide range
of bit rates and video resolutions compared to previous standards.
Compared to previous standards, the decoder complexity
is about four times that of MPEG-2 and two times that of
MPEG-4 Visual Simple Profile. This paper provides an overview
of the new tools, features and complexity of H.264/AVC.
200-MHz ARM920T Processor
• 16-kbyte Instruction Cache
• 16-kbyte Data Cache
• Linux® , Microsoft® Windows® CE-enabled MMU
• 100-MHz System Bus
• MaverickCrunch™ Math Engine
• Floating Point, Integer, and Signal Processing
Instructions
• Optimized for digital music compression and
decompression algorithms.
• Hardware interlocks allow in-line coding.
• MaverickKey™ IDs
• 32-bit Unique ID can be used for DRM-compliant
128-bit random ID.
• Integrated Peripheral Interfaces
• 32-bit SDRAM Interface
