1. "Digital Media Primer" Yue-Ling Wong, Copyright (c)2011 by Pearson Education, Inc. All rights reserved.

2. Video
motion
a sequence of pictures

3. Video
motion
a sequence of pictures
frames

4. Broadcast Standards Digital video resolution Color spaces Frame rate
Influenced by analog TV broadcast standards

5. Standards for Analog Color TV
NTSC:
designated by U.S.'s National Television Systems Committee
U.S., Japan, Taiwan, parts of the Carribean, South America
PAL:
Phase Alternating Line
Australia, New Zealand, Western Europe, Asian
SECAM:
Séquentiel Couleur avec Mémoire
France, former Soviet Union, Eastern Europe

6. Frame Rates of Different Broadcast Standards
Video Type
Frame Rate (frames per second)
NTSC (black-and-white) 30
NTSC (color)
29.97
PAL 25
SECAM
Motion-picture film 24

7. How CRT Monitors and TVs Display Pictures
Picture displayed on CRT is made up of horizontal lines
NTSC: 525 lines (about 480 lines are picture)
PAL and SECAM: 625 lines (about 576 lines are picture)
Lines are traced across the screen
one line at a time
from top to bottom

8. Ways of Tracing Lines From Top to Bottom
Progressive scan:
from top to bottom in one pass
Interlaced scan:
in two passes:
even-numbered lines
odd-numbered lines

9. Video Display: Interlaced Scan versus Progressive Scan
Also see the interactive tutorial:
Video Display: Interlaced Scan versus Progressive Scan
An interactive animation that illustrates two-pass scanning in interlaced scan and one-pass scanning in progressive scan.

10. Field Set of lines in the same pass 2 fields in interlaced scan:
even-numbered lines
odd-numbered lines
Upper field: the field that contains the topmost scan line
Lower field:
the other field

11. Undesirable Side Effects of Interlaced Scan
The two fields in a frame are captured at a slightly different moment in time
Discontinuities will become apparent for fast moving objects in video shot in the interlaced mode
Comb-like artifacts

12. Comb-like Artifacts

13. Upper Field

14. Lower Field

15. Video Recording: Interlaced Mode versus Progressive Mode
Also see the interactive tutorial:
Video Recording: Interlaced Mode versus Progressive Mode
An interactive animation that illustrates how the interlace artifact may be produced in fast-action videos.

16. Upper Field and Lower Field
Also see the interactive tutorial:
Upper Field and Lower Field
An interactive demo shows the upper field and the lower field of a video frame.

17. Fast-Action Digital Video Showing the Interlace Artifact
Also check out the video:
Fast-Action Digital Video Showing the Interlace Artifact
The soccer practice video clip from which the example is using here to show the comb-like interlace artifact.

18. Interlace Artifacts
Not discernible during normal playback of most videos

19. Deinterlace To remove the interlace artifact Common method:
discard one field
fill in the gaps by duplicating or interpolating the other field

20. Deinterlaced Result

21. Color Format for Videos
Luminance-chrominance color models
Luminance: brightness Chrominance: color or hue

22. Luminance-chrominance Color Model Examples
YUV:
Y: luminance component
U and V: chrominance components
used for PAL
YIQ:
I and Q: chrominance components
used for NTSC

23. Review Question
Which of the following is the television broadcast standard for the U.S. and Japan?
NTSC
PAL
SECAM A

24. Review Question
Which of the following is the television broadcast standard for most of the Asian countries?
NTSC
PAL
SECAM B

25. Review Question
In the YUV color model, the Y-component is ___, the U-component is ___, and V-component is ___.
luminance; luminance; chrominance
luminance; chrominance; luminance
luminance; chrominance; chrominance
chrominance; chrominance; luminance
chrominance; luminance; luminance C

26. Review Question The frame rate for the NTSC system is ___ fps. 24 25
28.9
29.97 30 D

27. Review Question The frame rate for the PAL system is ___ fps. 24 25
28.9
29.97 30 B

28. Review Question
The frame rate for the the motion-picture film is ___ fps. 24 25
28.9
29.97 30 A

29. Review Question The scan mode of a CRT computer monitor is ___.
interlaced
progressive A

30. Review Question The scan mode of a CRT television set is ___.
interlaced
progressive A

31. Review Question
Interlaced scan displays the frame by scanning the lines of a frame ___.
in one pass from top to bottom
in two passes: even-numbered lines in one pass and odd-numbered lines in the second B

32. Review Question
Progressive scan displays the frame by scanning the lines of a frame ___.
in one pass from top to bottom
in two passes: even-numbered lines in one pass and odd-numbered lines in the second A

33. Review Question
The comb-like artifact in a digital video, as shown here, occurs in the ___ video.
interlaced
progressive
both A and B A