1. Media signal Media format Last updated on June 15, 2010 Doug Young Suh suh@khu.ac.kr

2. Go to basics  “I learned everything in Kindergarten.”  What did I learn in Kindergarten for video coding? Probability theory, linear algebra, sampling theory

3. Media signal AD conversion Analog = continuous time + analog Digital = discrete time + digital

4. Media signal Sampling and human-being Low freq. High frequency Sampling theory (Nyquist theory) Sampling frequency f s > 2f max Speech 8kHz > 2 X 3.2kHz Audio 44.1kHz > 2 X 20kHz Video Temporal : 24Hz (movie), 60Hz (TV) Spatial 440Hz, A, Ra Do-Re-Mi-Pa-Sol-Ra-Si-Do

5. Media signal Quantization Analog digital Analog : infinite number of values Digit-al : finite number of values

6. Media signal Quantization and de-quantization  Loss of information, but acceptable accuracy

7. Media signal Image Resolution Original image :256*256, 8bits 128*128, 8bits 256*256, 4bits

8. Media signal Color representation RGB cf) rectangular coordinate YCbCr (YUV) cf) polar coordinate Red (255,0,0) Blue (0,0,255)

9. Original Red Green Blue 4:4:4 Y U V U, V no high freq.  4:2:2  4:2:0 Color representation

10. Media signal RGB  YC b C r Y = 0.29900R+0.58700G+0.11400B C b = -0.16874R-0.33126G+0.50000B C r = 0.50000R-0.41869G-0.08131B YC b C r  RGB R=1.00000Y+1.40200C r G=1.00000Y-0.34414C b -0.71414C r B=1.00000Y+1.77200C b Color conversion  1 to 1 mapping

11. Media signal Color conversion  4:4:4  1+1+1  4:2:2 Horizontally 2:1 subsampling  4:2:0  1+ 1/4 + 1/4  Most popular  Amount ½

12. Video formats  QCIF  CIF(352x288)  4CIF  QVGA  VGA(640x480)  SXGA(1280x1024)

13. Networked Video VLCQ DCT Motion Estimation + Frame Memory Original Video Encoded Bitstream Video encoding IQ IDCT Motion vector 2-3 2-2 2-1