6. What is Video?
Video is electronically captured and
disseminated sequential still images
(frames) in rapid enough succession to
create the illusion of motion, stored
either analog or digitally, and
synchronized with sound.
7. What is Video?
Video is electronically captured and
disseminated sequential still images
(frames) in rapid enough succession to
create the illusion of motion, stored
either analog or digitally, and
synchronized with sound.
8. Analog
• A wave is recorded or used in its original form
• Light or sound are converted to a fluctuating electrical wave that
is directly recorded, usually to a magnetic tape
medium, mirroring the original stimulus.
• It produces an electrical copy of an original stimulus.
• Analog signal fluctuates exactly like the original stimulus.
• Analog signal is continuous.
9. Digital
• The analog wave is sampled at some interval, and then turned
into numbers that are stored in the digital device
• Light and sound are recorded not as an identical copy of the
original stimulus, but as discrete on-and-off pulses, zeros and
ones, binary digits.
• It is a representation rather than a copy.
• Discontinuous. Signal is sampled.
• Advantage: Resists data distortion and error in duplication. No
generational loss.
• Advantage: Allows for manipulation of sound and image.
13. Digital
• Sampling/Quantizing
• Compression and Codecs (Compression-
Decompression, Encoding-Decoding)
• Downloading and Streaming
Advantages
• Lossless Copying
• Compression
• Manipulation
14. Basic Image Formation
Compression
• CODEC – a device or program for encoding and/or
decoding digital information
(DivX, Xvid, H.264, WMV, etc.)
• Container of Wrapper Format
(AVI, FLV, QuickTIme, MPEG, MP4, etc.)
• Lossy vs. Lossless
• Lossy - Permanently removes information, such as
repeated pixels.
• Lossless - Compresses and decompressed without
loss of information.
• Compression Ratio - the higher the ratio, the smaller
the file; the lower the ratio, the higher the quality.
17. What is Video?
Video is electronically captured and
disseminated sequential still images
(frames) in rapid enough succession to
create the illusion of motion, stored
either analog or digitally, and
synchronized with sound.
19. Sequential Still Images (Frames)
• The individual pictures that make up
video are “frames.”
• The frames are comprised of millions of
electrically excitable “pixels” (picture
elements)
20. Pixels
• The individual pictures that make up
video are “frames.”
• The frames are comprised of millions of
electrically excitable “pixels” (picture
elements)
• For color, each pixel is comprised of
three parts (red, blue, green)
24. Sequential Still Images (Frames)
• The individual pictures that make up
video are “frames.”
• The frames are comprised of millions of
electrically excitable “pixels” (picture
elements)
• For color, each pixel is comprised of
three dots (red, blue, green)
• Individual images are drawn by
scanning along these pixels from left to
right, top to bottom.
25.
26. Scanning
High speed video showing the fluorescent screen of
CRT television being scanned by electron gun.
http://youtu.be/zVS6QewZsi4
36. Resolution
Digital Television (DTV)
• Higher Picture Resolution
• Truer Color
• Wider Contrast Ratio
Four prominent systems:
• 480p (progressive, 480 visible lines, 60 frames per
second)
• 720p (progressive, 720 visible lines, 60 frames per
second, High Definition Television [HDTV]
• 1080i (interlaced, 60 fields/30 frames per
second, High Definition Television [HDTV]
• 1080p (progressive, 60 frames per second, [HDTV]
42. Resolution
Additional Systems
24p - 1080 lines of resolution, 24 frames per second.
• For use in conjunction with motion picture film
• Or to create a “film look.”
45. Resolution
Resolution – The Detail an Image Contains
• Horizontal lines of pixels times vertical lines of pixels
• VHS - 200 by 480
• Mini-DV - 720 by 480
• CineAlta 24p - 1920 by 1080
• 35mm film - 4000 by 3000
• Red One - 4520 by 2540
46. Resolution
Resolution – The Detail an Image Contains
• Horizontal lines of pixels times vertical lines of pixels
Analog and early digital
• 300×480 : VHS,
• 500×480 : Analog broadcast
47. Resolution
Resolution – The Detail an Image Contains
• Horizontal lines of pixels times vertical lines of pixels
Digital
• 720×480 :DVD, miniDV
• 1280×720 (-1MP) : HD DVD, Blu-ray, HDV (miniDV)
• 1440×1080 (1.5 MP) : HDV (miniDV)
• 1920×1080 (2MP) : HDV (miniDV), AVCHD, HD DVD, Blu-ray,
• 2048×1080 : 2K Digital Cinema
• 4096×2160 : 4K Digital Cinema
• Sequences from newer films are scanned at 2,000, 4,000, or
even 8,000 columns, called 2K, 4K, and 8K, for quality visual-
effects editing on computers
48. What is Video?
Video is electronically captured and
disseminated sequential still images
(frames) in rapid enough succession to
create the illusion of motion, stored
either analog or digitally, and
synchronized with sound.
50. Frame Rates
The number of frames captured in a
second
(frames per second)
Shutter Speed -
The time light is allowed to strike the
image sensor to create a single
image.
(fraction of a second)
51. Frame Rates
(frames per second)
Higher frame capture and playback rates result in more
information and higher picture quality with increased
sharpness, less stutter and flicker, and less motion blur.
52.
53. Frame Rates
(frames per second)
Impact on Image Quality and Smoothness of Motion
http://youtu.be/e54Q1KXRmX0
54. Frame Rates
(frames per second)
Impact on Image Quality and Smoothness of Motion
http://youtu.be/-nU2_ERC_oE
55. Frame Rates
(frames per second)
Impact on Image Quality and Smoothness of Motion
http://youtu.be/3xsSSsVqSA0
56. Frame Rates
(frames per second)
Impact on Video Speed
When video is played back at the same frame rate as it
was captured, motion appears normal.
When video capture speed is faster than it is played
back, slow motion results, since the video is playing
back at a SLOWER speed than it was captured.
30fps Capture - 30fps Playback: Normal Motion
60fps Capture - 60fps Playback: Normal Motion
60fps Capture - 30fps Playback: Slow Motion
300fps Capture - 30fps Playback: Slow Motion
57. Frame Rates
(frames per second)
Impact on Video Speed
When video is played back at the same frame rate as it
was captured, motion appears normal.
When video capture speed is slower than it is played
back, fast motion results, since the video is playing back
at a FASTER speed than it was captured.
30fps Capture - 30fps Playback: Normal Motion
60fps Capture - 60fps Playback: Normal Motion
30fps Capture - 60fps Playback: Fast Motion
3fps Capture - 30fps Playback: Fast Motion
58. Frame Rates
(frames per second)
Impact on Video Speed
When video is played back at the same frame rate as it
was captured, motion appears normal.
When video playback speed is altered in post
production to a slower frame rate than it was
captured, slow motion results, since the video is playing
back at a SLOWER speed than it was captured.
30fps Capture - 30fps Playback: Normal Motion
60fps Capture - 60fps Playback: Normal Motion
60fps Capture -30fps (or 50%) Playback: Slow Motion
60fps Capture - 6fps (10%) Playback: Slow Motion
59. Frame Rates
(frames per second)
Impact on Video Speed
When video is played back at the same frame rate as it was
captured, motion appears normal.
When video playback speed is altered in post production to a faster
frame rate than it was captured, fast motion results, since the video
is playing back at a FASTER speed than it was captured.
30fps Capture - 30fps Playback: Normal Motion
60fps Capture -60fps Playback: Normal Motion
60fps Capture -120fps (or 200%) Playback: Fast Motion
60fps Capture - 600fps (1000%) Playback: FAST Motion
60. Frame Rates
(frames per second)
Impact on Image Speed
http://vimeo.com/11648907
61. Frame Rates
(frames per second)
Impact on Image Speed
http://youtu.be/kgdyBvHdNKY
62.
63.
64.
65. Shutter Speed
(fraction of a second)
Generally, shutter speed must be at least half of the
frame rate. At 30 frames per second, the shutter speed
will be approximately 1/60th of a second.
It can be faster is the camera allows.
A higher frame rate requires a faster shutter speed.
Shutter speed can be increased independent of the
frame rate.
A faster the shutter speed results in diminished blur
A slower shutter speed results in added blur.
73. Shutter Speed
(fraction of a second)
Impact on Motion Blur
http://vimeo.com/18873243
74. Shutter Speed
(fraction of a second)
Impact on Motion Blur
http://youtu.be/gFjbVZJ275k
75. Shutter Speed
(fraction of a second)
Impact on Motion Blur
http://vimeo.com/20310729
76.
77. What is Video?
Video is electronically captured and
disseminated sequential still images
(frames) in rapid enough succession to
create the illusion of motion, stored
either analog or digitally, and
synchronized with sound.
78. The Illusion of Motion
• Persistence of Vision, Beta Movement, Phi Phenomenon
http://www.youtube.com/watch?v=3veFqnnob0A
79. The Illusion of Motion
• Persistence of Vision, Beta Movement, Phi Phenomenon
80. The Illusion of Motion
• Flicker Fusion and Frequency - the
flickering of light rapidly enough to
merge or fuse the images
• Apparent motion - Creating the illusion
of motion
81. Basic Image Formation
• Scanning
• Fields / Frames
• Flicker Frequency: Flashes per second
• Apparent motion
• Frames per second
http://dsc.discovery.com/videos/assignment-discovery-
shorts-tv-tube-and-the-flicker-frequency.html
83. Basic Image Formation
Recording Media
• Film Stock
• Analog Video Cassette tape
• Digital Video Cassette tape
• DVD discs
• Digital Hard Drives
• Digital Memory Cards
84. NTSC
National Television System Committee
• http://www.ehow.com/video_4751914_
what-ntsc-video.html
• http://www.ehow.com/video_4751915_
what-difference-between-ntsc-pal.html