compression is lossless.
compression is lossy.
higher compression ratios than do lossless
Compressors.
**the data compression ratio is analogous to the physical
compression
ratio used to measure physical compression of substances
MP
"he one of compression technologies use a lossy compression
techni#ue is MPEG (Mo$ing Picture %perts roup)
MP algorithms compress data to form small bits that can be
easily transmitted and then uncompressed& MP achie$es its high
compression rate by storing only the changes from one frame to
another, instead of each entire frame& "he $ideo
information is then encoded using a
techni#ue called DCT (Discrete Cosine "ransform)
DC"
"31 '01(01 DC")?
"he use of cosine rather than sine functions is critical
for compression, since it turns out that feer
cosine functions are needed to appro%imate a
typical signal, hereas for differential e#uations
the cosines e%press a particular choice of boundary
conditions.
**DC" is a 4ourier5related transform similar to the discrete
4ourier
transform (D4"), but using only real numbers.
