Multimedia Concepts: Video Technologies

Multimedia Concepts:Video TechnologiesANALOGDIGITAL

Analog Video Technology Analog means ?

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

Analog Video Technology Videotape Laserdisc

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

Video (Analog Tape)Positives RECORDABLE & erasableInexpensive hardware & tapesCan be digitized

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

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

Analog Video Technologies Videotape Laserdisc (Laser videodisc)

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

Laserdiscs +/- AdvantagesHigher video qualityMulti-channel soundDouble-sidedStill frame & special effectsPotential for random access Non-linear = hyper

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

Multimedia Concepts:Video TechnologiesANALOGDIGITAL

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

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

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

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

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

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

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

Digital Video Benefits Inexpensive hardware to create Edit electronically with software (non-linear editing) Just another (large) file = transmission potential FTP, email, or on web pages Keep file size down! Or stream it 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 Codec compatibility / availability Storage requirements / downloads

Impact of File Size1 min video can take minutes to download

K/sec

100K

1MB

28.8K

3.0

33 sec

6 min

56K

6.0

17 sec

3 min

T1

Cable / DSL

150

variable

0.7 sec

7 sec

DV FormatsQuickTime (mov) Background / compatibilityVideo for Windows (avi)WMVMPEG (mpg, mp#) Current standard ? Video CD / DVDStreaming competition (later) Real vs MS vs QT

Exotic DVVCD (Video CD)Mpeg-1 Common outside US QTVRLighthouse (HS)Orlando Art Museum

Other Digital Video Topics Creating digital video DVD Streaming