Presentation on theme: "Kompresja danych... accept the convention that the word "compression" be encoded as "comp".... ZIP file format... both the sender and receiver of the information."— Presentation transcript:
Kompresja danych... accept the convention that the word "compression" be encoded as "comp".... ZIP file format... both the sender and receiver of the information understand the encoding scheme... Lossless vs. lossy compression
Claude E. Shannon, 1948 A Mathematical Theory of Communication 0. xfoml rxkhrjffjuj zlpwcfwkcyj ffjeyvkcqsghyd qpaamkbzaacibzlhjqd 1. ocroh hli rgwr nmielwis eu ll nbnesebya th eei alhenhttpa oobttva nah 2. on ie antsoutinys are t inctore st be s deamy achin d ilonasive tucoowe 3. in no ist lat whey cratict froure birs grocid pondenome of demonstures 4....
MP3 digital audio encoding and lossy compression format, 1991, ISO... psychoacoustic models... tradeoffs between data size and sound quality... bit rate 128 - 320 kbit /s... compression artifacts... sound of applause: it is hard to compress because of its randomness and sharp attacks CD parameters: 44.1 kHz, 2 channels, 16 bits per channel -> 1411.2 kbit/s
JPG Joint Photographic Experts Group 1994, ISO 10918-1 method of compression for photographic images lossy compression... from RGB into a different color space called YCbCr... discrete cosine transform MPEG Moving Picture Experts Group
GIF Graphics Interchange Format... limited to a palette of 256 colours or less... Unisys... owned some patents to key parts of the GIF compression technology, and has started demanding fees from every company whose software uses the (freely available) GIF code bmp 24bit - 29,3 KB gif – 14,0 KB bmp 256kolor – 10,8 KB