Multimedia Concepts: Video Technologies ANALOG DIGITAL

Analog Video Technology Analog means ? Analog means ?

Analog Video Technology Analog Formats Videotape Videotape  VHS (remember BETA?)  8mm Laserdisc Laserdisc Familiar? Obsolete? Familiar? Obsolete? Why discuss? Why discuss?

Analog Video Technology Videotape Videotape Laserdisc Laserdisc

Video (Analog Tape) Positives Familiar, common hardware Familiar, common hardware  VCRs, players, camcorders Perceived image “quality” Perceived image “quality”  Impact of screen size Full color depth (~ 24-bit) Full color depth (~ 24-bit)

Video (Analog Tape) Positives RECORDABLE & erasable RECORDABLE & erasable Inexpensive hardware & tapes Inexpensive hardware & tapes Can be digitized Can be digitized

Video (Analog Tape) Negatives Quality of NTSC (standard N. Am. television) Quality of NTSC (standard N. Am. television) TV vs. Monitor TV vs. Monitor Fundamentally linear Fundamentally linear  Hard to use segments  Example (s)  Computer control ??

Video (Analog Tape) Negatives Limited manipulation Limited manipulation  Costly hardware to edit  Quality loss by generation Distance distribution Distance distribution  Limited rapid sharing  cf. video conferencing

Analog Video Technologies Videotape Videotape Laserdisc (Laser videodisc) Laserdisc (Laser videodisc)

Laserdisc (Analog) Overview Precursor to DVD Precursor to DVD Advantages & Disadvantages Advantages & Disadvantages Laserdisc technology Laserdisc technology Advanced systems Advanced systems

Laserdiscs Laserdiscs +/- Advantages Advantages Higher video quality Higher video quality Multi-channel sound Multi-channel sound Double-sided Double-sided Still frame & special effects Still frame & special effects Potential for random access Potential for random access  Non-linear = hyper

Laserdiscs Laserdiscs +/- Disadvantages Disadvantages ‘Special’ hardware ‘Special’ hardware  Unfamiliar at home Bulky Bulky Cost of hardware Cost of hardware  vs VCR (or DVD) No local recording No local recording

Multimedia Concepts: Video Technologies ANALOG DIGITAL

Digital Video What is it? Most commonly: Most commonly:  Analog video – digitized  Computer files Newer technology: Newer technology:  Original digital video (DV)  Bits on a digital tape

Creating Digital Video Hardware Analog Digitizing Gear Analog Digitizing Gear  $50 - $1000+  Internal, external, both Digital camcorder + IEEE 1394 Digital camcorder + IEEE 1394  “Firewire” or “i Link” Many digital ‘still’ cameras Many digital ‘still’ cameras  Highly variable results PC / web cameras (“golf balls”) PC / web cameras (“golf balls”)

Creating Digital Video Software Comes with hardware Comes with hardware Capture, then edit Capture, then edit  Not necessarily same software Varied features, e.g. formats Varied features, e.g. formats Varied learning curve Varied learning curve  Match to need & skill  iMovie / Movie Maker to Premier

Other Digital Video Sources Clip video (CD / Web) Clip video (CD / Web) Download from web sites Download from web sites  Varies by video format “Screen capture” software “Screen capture” software  Camtasia, CamStudio, etc. Morphing software Morphing software Animation software Animation software  Flash, et al – beyond our scope Class web page has links Class web page has links

Digital Video Concepts Video = “frames” Video = “frames”  How many / sec? Apply still image file size concept Apply still image file size concept Video = ++MB Video = ++MB  Forget KB  Forget KB

Digital Video Concepts Image Size (‘window’ on screen) Image Size (‘window’ on screen)  Pixel dimensions Common Sizes Common Sizes  160 x 120 (‘1/16’)  320 x 240 (‘1/4’)  640 x 480 (‘full’ screen)  720 x 480 (DVD, ‘wider’ screen)  What does a viewer really see?

Digital Video Concepts DV File Size Factors Image pixel dimensions Image pixel dimensions  Just like still images FPS FPS  Frames per second  Number required? Color depth (bits) Color depth (bits)  Increasingly, no option

Digital Video Concepts DV File Size Factors  Video (file) format (more later) QuickTime / AVI / WMV QuickTime / AVI / WMV MPEG (mpg) MPEG (mpg) Streaming Streaming  CODEC Compression / decomp algorithm Compression / decomp algorithm Sometime selectable (cf. audio) Sometime selectable (cf. audio)  Audio quality Limited impact Limited impact

Digital Video Benefits Inexpensive hardware to create Inexpensive hardware to create Edit electronically with software (non-linear editing) Edit electronically with software (non-linear editing) Just another (large) file = transmission potential Just another (large) file = transmission potential  FTP, , or on web pages  Keep file size down!  Or stream it More flexible use More flexible use

Digital Video Issues  Image quality (e.g. jaggies)  Limited resizing (pixels, jerky)  Differing formats / architectures  Non-standard compression schemes Broadway AVI & M-JPEG Broadway AVI & M-JPEG Codec compatibility / availability Codec compatibility / availability  Storage requirements / downloads

Impact of File Size 1 min video can take minutes to download

DV Formats QuickTime (mov) QuickTime (mov)  Background / compatibility Video for Windows (avi) Video for Windows (avi) WMV WMV MPEG (mpg, mp#) MPEG (mpg, mp#)  Current standard ?  Video CD / DVD Streaming competition (later) Streaming competition (later)  Real vs MS vs QT

‘Exotic’ DV VCD (Video CD) VCD (Video CD)  Mpeg-1  Common outside US QTVR QTVR  Lighthouse (HS)  Orlando Art Museum

Other Digital Video Topics Creating digital video Creating digital videoCreating digital videoCreating digital video DVD DVDDVD Streaming StreamingStreaming