compression is the key to effective information delivery

Mediauncompressedcompressed
voice 8k samples/sec, 8 bits/sample64 kbps2-4 kbps
slow motion video 10fps 176x120 8 bits5.07 Mbps8-16 kbps
audio conference 8k samples/sec 8bits64 kbps16-64 kbps
video conference 15 fps 352x240 8bits30.4 Mbps64-768 kbps
audio (stereo) 44.1 k samples/s 16 bits1.5 Mbps128k-1.5Mbps
video 15 fps 352x240 15 fps 8 bits30.4 Mbps384 kbps
video (CDROM) 30 fps 352x240 8 bits60.8 Mbps1.5-4 Mbps
video (broadcast) 30 fps 720x480 8 bits248.8 Mbps3-8 Mbps
HDTV 59.9 fps 1280x720 8 bits1.3 Gbps20 Mbps

Codec = (en)coder + decoder


images, video, audio are amenable to compression:

B. Vasudev & W. Li, Memory management: Codecs


Handbook of Multimedia Management, p 237-278


encoding & decoding



  
  signal  -> source coder   ->  channel coder    (encoding)
  
  signal  <- source decoder <-  channel decoder  (decoding)
  
  

codec design problem


From a systems design viewpoint, one can restate the codec design problem as a bit rate minimization problem, meeting (among others) constraints concerning:

classification of compression methods


tradeoffs

issues in compression selection

standard-based codecs

pixels versus objects


pixel-based standards

object-based codec(s)