emc 3130/2130 lecture one - image digital
TRANSCRIPT
EMC 3130
Lecture OneDigital Video – How Does This Work?
Pixels to Scenes
Edward Bowen
A Concise Explanation of Television
http://www.youtube.com/watch?v=UivqdpliyA0
Digital Camera Deconstructed
http://www.youtube.com/watch?v=nSF3xdIWrPI
What is Video?
Video is sequential still images (frames), electronically captured, stored and disseminated in rapid enough succession to create the illusion of motion, synchronized with sound.
What is Video?
Video is sequential still images (frames), electronically captured, stored and disseminated in rapid enough succession to create the illusion of motion, synchronized with sound.
Sequential Still Images (Frames)• The individual pictures that make up
video are “frames.”
Sequential Still Images (Frames)
Sequential Still Images (Frames)
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)
Pixels
Pixels
Paper Pixelshttp://youtu.be/DCTRk5a0aJg
Pixels
Pantone Pixels http://vimeo.com/18881890
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)
Pixels
This Is Not Yellow http://youtu.be/R3unPcJDbCc
Aside – A History Lesson
The Man Who Turned Paper into Pixels https://vimeo.com/98345492
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 (frames) are drawn by scanning along these pixels from left to right, top to bottom.
Scanning
High speed video showing the fluorescent screen of CRT television being scanned by electron gun.
http://youtu.be/zVS6QewZsi4
Scanning
http://www.dailymotion.com/video/xjoyzr_cbs-entertainment-productions-london-films-persistence-of-vision-mgm-television_shortfilms
Scanning• Interlaced Scanning - Two fields
comprise a frame.
Scanning
• Interlaced Scanning
Interlaced Artifacts
Scanning
• Interlaced Scanning
Interlaced Artifacts
Scanning• Progressive Scanning (Computers and
Most Digital Video)
Scanning
• Progressive v Interlaced Scanning
Scanning
• Progressive v Interlaced Scanning
Scanning
http://video.answers.com/how-ntsc-interlaced-video-works-291907666
Scanning
Progressive VS Interlaced Video Modes and Pixel Aspect Ratio Part 1 http://youtu.be/9D8cRFMedGY
Scanning
1080i vs 1080p [interlaced vs progressive] 1080p FULL HDhttp://youtu.be/j29b7B6CSNM
Scanning
The Joy of Interlacing https://vimeo.com/1513146
ResolutionThe quality of the image, a result of the number of lines,
therefore the number of pixels, often measured in megapixels, that comprise an individual frame.
Pixel count is the number of horizontal lines multiplied by the number of vertical lines.
One megapixel is ROUGHLY 1 million pixels.
Resolution• The more lines, the more pixels.• The more pixels, the more information.• The more information, the higher the resolution.• Resolution is defined as the number of horizontal lines of
pixels in an image.
How A Camcorder Works
How-a-Digital-Camera-Works---CMOS-chip.mov http://youtu.be/Z3co311bBqY
Resolution
Old Style Standard Television
• 480i (480 horizontal lines visible, interlaced; 30 frames per second)
ResolutionDigital 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] (Roughly 1 Megapixel)
• 1080i (interlaced, 60 fields/30 frames per second, High Definition Television [HDTV] (Roughly 2 Megapixels)
• 1080p (progressive, 60 frames per second, [HDTV] (Roughly 2 Megapixels)
Resolution
Resolution
720p 1080p
Resolution
Resolution
800 Megapixel Panorama of Milky Wayhttp://youtu.be/MH9R6MpC3AQhttp://www.wired.com/wiredscience/2009/09/panorama/
Resolution
Dubai 45,000 Megapixel Photo - World's Largest Photohttp://youtu.be/1r6z21aEJJ0http://www.engadget.com/2010/05/10/gigapan-epic-pro-helps-create-44-880-megapixel-panorama-of-dubai/
Resolution
Skybox Imaging Captures World’s First High-Resolution, HD Video of Eartrh from Spacehttp://youtu.be/fCrB1t8MncYhttp://www.skyboximaging.com/news/FirstHigh-ResolutionHDVideoofEarth
Resolution
Additional Systems
2K, 4K and 5K – 2000, 4000 and 5000 lines of resolution
• For use in theatrical screening and 35mm scanning
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
Resolution – It’s Always More Complicated
What is the Resolution of the Eye? http://youtu.be/4I5Q3UXkGd0
What is Video?
Video is sequential still images (frames), electronically captured, stored and disseminated in rapid enough succession to create the illusion of motion, synchronized with sound.
Digital• Step 1 – Light enters the camera
Digital• Step 1 – Light enters the camera• Step 2 – It is converted to electrical signals
Digital• Step 1 – Light enters the camera• Step 2 – It is converted to electrical signals• Step 3 – The electrical signal is copied or converted and
stored. When accomplished digitally, the result is a computer file.
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.
Analog• Light as it enters a camera is always analog.
But, you know, who cares? Everything is digital now anyway.
Digital Conversion• 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.
Digital
Analog or Digital? (1993) http://youtu.be/kR7227_ndqQ
Digital
http://on.aol.com/video/dr--michio-kaku-on-the-conversion-from-analog-to-digital-517068293
Digital
Digital
Digital• Sampling/Quantizing – The electrical signal is
sampled.
Digital
Lots of Codecs - http://youtu.be/wRwBlb_23Ug
Digital
• The resulting computer information is compressed. • Compression reduces computer file size, usually by
discarding hopefully unneeded information– Frame (Remove frames)– Picture (Remove redundancy between frames)– Color (Reduce variety of colors)– Sound (Reduce frequencies)
• This compression is accomplished by a CODEC.• CODEC – a device or program for encoding and/or
decoding digital information (DivX, Xvid, H.264, WMV, etc.)
Digital
http://www.lynda.com/Premiere-Pro-tutorials/use-codecs/149702/154476-4.html?vid=6&fatoc=1
The Use of Codecs – Lynda.com
Digital
Video Codecs 101 http://youtu.be/7YQ1mikDhIo
Basic Image Formation
Compression• The CODEC is a device or program for encoding
and/or decoding digital information. It converts and compresses the video computer file –(DivX, Xvid, H.264, WMV, etc.)
• Additionally, the file exists in a Container or Wrapper Format (AVI, FLV, QuickTIme, MPEG, MP4, etc.). This will be the file’s extension (.mov, .mpeg, etc.)
• Compression Ratio - the higher the ratio, the smaller the file; the lower the ratio, the higher the quality.
Basic Image Formation
Compression• Lossy vs. Lossless• Lossy - Permanently removes information, such as
repeated pixels. High compression ratio.• Lossless - Compresses and decompresses without
loss of information. Low compression ratio.
Digital Compression As Art
http://youtu.be/nH3nmBEPIHYPlus De Deux
Digital Compression
http://nofilmschool.com/2013/02/compression-encoding-basics-artifact-removal-tutorials/
Digital Compression
Basics of Video Compression - http://www.larryjordan.biz/basics-of-video-compression-video/
What is Video?
Video is sequential still images (frames), electronically captured, stored and disseminated in rapid enough succession to create the illusion of motion, synchronized with sound.
Frame Rates (frames per second)
Shutter Speed (fraction of a second)
Frame RatesThe 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)
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.
Frame Rates (frames per second)
Video Basics: Frame Rate http://youtu.be/8c8DrVvELe4
Frame Rates (frames per second)
Impact on Image Quality and Smoothness of Motion
Video Frame Rate Comparison http://youtu.be/e54Q1KXRmX0
Frame Rates (frames per second)
Impact on Image Quality and Smoothness of Motion
GoPro HD Hero 30fps vs. 60fps http://youtu.be/-nU2_ERC_oE
Frame Rates (frames per second)
Impact on Image Quality and Smoothness of Motion
30vs60.wmv http://youtu.be/3xsSSsVqSA0
Frame Rates
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.”
Resolution
The_24p_Conspiracyhttp://vimeo.com/3388256
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.
Frame Rates (frames per second)
Impact on Video Speed (High Speed Capture)
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 Motion60fps Capture - 60fps Playback: Normal Motion
60fps Capture - 30fps Playback: Slow Motion300fps Capture - 30fps Playback: Slow Motion
Frame Rates (frames per second)
Impact on Image Speed (High Speed Capture)
http://vimeo.com/11648907
Frame Rates (frames per second)
Impact on Image Speed (High Speed Capture)
Action Figure Slow Motion Punches http://youtu.be/kgdyBvHdNKY
Frame Rates (frames per second)
Impact on Image Speed (High Speed Capture)
http://youtu.be/EtsXgODHMWk
Frame Rates (frames per second)
Impact on Image Speed (High Speed Capture)
Ramesh Raskar: Imaging at a trillion frames per second http://youtu.be/Y_9vd4HWlVA
Frame Rates (frames per second)
Impact on Image Speed (High Speed Capture)
http://youtu.be/9RbLLYCiyGE
Frame Rates (frames per second)
Impact on Image Speed (High Speed Capture)
Two Forty from Brighton: Sony FS700 https://vimeo.com/42663128
Frame Rates (frames per second)
Impact on Image Speed (High Speed Capture)
Exploring Frame Rates and Resolutions on a Phantom Flex High Speed Camera - Video Bloghttps://vimeo.com/48571597
Frame Rates (frames per second)
Impact on Image Speed (High Speed Capture)
The Slow Mo Guys https://www.youtube.com/channel/UCUK0HBIBWgM2c4vsPhkYY4w
Frame Rates (frames per second)
Impact on Video Speed (Slowed in Post)
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 Motion60fps Capture - 60fps Playback: Normal Motion
60fps Capture -30fps (or 50%) Playback: Slow Motion60fps Capture - 6fps (10%) Playback: Slow Motion
Frame Rates (frames per second)
Impact on Video Speed (Slowed in Post)
Final Cut Pro X Super Slow Motion in Optical Flow https://vimeo.com/26626015
Frame Rates (frames per second)
Impact on Video Speed (Slowed in Post)
Twixtor Software 7D 1000 fps https://vimeo.com/13557939
Frame Rates (frames per second)
Impact on Video Speed (Slowed in Post)
Surfing –GoPro- Time Warp SlowMotion http://youtu.be/JWblwHPQZj4
TimeWarp Software
Frame Rates (frames per second)
Impact on Video Speed (High Speed / Time Lapse)
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 Motion60fps Capture - 60fps Playback: Normal Motion
30fps Capture - 60fps Playback: Fast Motion3fps Capture - 30fps Playback: Fast Motion
Frame Rates (frames per second)
Impact on Video Speed (High 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 Motion60fps Capture -60fps Playback: Normal Motion
60fps Capture -120fps (or 200%) Playback: Fast Motion60fps Capture - 600fps (1000%) Playback: FAST Motion
Frame Rates (frames per second)
Impact on Video Speed (High Speed / Time Lapse)
Koyaanisqatsi http://youtu.be/mzsmU5sXM1M
Frame Rates (frames per second)
Impact on Video Speed (High Speed / Time Lapse)
Skywalker ranch timelapse test https://vimeo.com/8013220
Frame Rates (frames per second)
Impact on Video Speed (High Speed / Time Lapse)
"The City Limits" (Cities in fast motion accompanied with Hans Zimmers "Time" )http://youtu.be/I1gxvG9roDM
Frame Rates (frames per second)
Impact on Video Speed (High Speed / Time Lapse)
Celestial Lights https://vimeo.com/40555466
Frame Rates (frames per second)
Impact on Video Speed (High Speed / Time Lapse)
Nightfall https://vimeo.com/47224216
Frame Rates (frames per second)
Impact on Video Speed (High Speed / Time Lapse)
Yosemite Range of Light https://vimeo.com/40802206
Frame Rates (frames per second)
Lynda.com – Exploring Frame Rates – http://www.lynda.com/Final-Cut-Pro-tutorials/Exploring-frame-rate-choices/103707/109583-4.html?vid=6&fatoc=1
NTSCNational 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
NTSC• The Americas, Japan Pretty Much Everywhere
Else • 60 Hertz Electric Current 50 Hertz Electric Current• 24, 30 and 60 fps 25 and 50 fps
PAL
What is Video?
Video is sequential still images (frames), electronically captured, stored and disseminated in rapid enough succession to create the illusion of motion, synchronized with sound.
The Illusion of Motion• Persistence of Vision, Beta Movement, Phi Phenomenon
Muybridge-horse-in-motion.mov http://www.youtube.com/watch?v=3veFqnnob0A
The Illusion of Motion• Persistence of Vision, Beta Movement, Phi Phenomenon
What is Persistence of Vision? (Mr. Wizard)http://youtu.be/YismwdgMIRc
The Illusion of Motion• Persistence of Vision, Beta Movement, Phi Phenomenon
Thaumatropes & the Persistence of Vision https://vimeo.com/44274189
The Illusion of MotionWhat’s needed for Apparent Motion - Creating the illusion of motion
• Flicker Fusion or Frequency – the number of flashes of light per second to merge or fuse the images, so that the flicker itself is invisible. At least 50 to 60 flashes per second.
• Frame Rate – the number of images per second needed to create the illusion of motion. At least 16 images per second.
Basic Image Formation
• Scanning• Fields / Frames• Flicker Frequency• Apparent motion• Frames per second
http://dsc.discovery.com/videos/assignment-discovery-shorts-tv-tube-and-the-flicker-frequency.html
Overview
Interlaced and Progressive Frame Rates Explained! : FRIDAY 101http://youtu.be/xKMWjRlIvrY
Overview
Progressive VS Interlaced Video Modes and Pixel Aspect Ratiohttp://youtu.be/9D8cRFMedGY
Blur
What is Video?
“Now in the real world things just happen … things just continuously happen.”
