Video Equipment September 16, 1999 Lawrence A. Rowe University of California, Berkeley URL: L.A. Rowe

Multimedia Systems and Applications2 Outline Routing Switchers, distribution amplifiers, etc. Clock/Time Film/Video Transfer Video Production Switchers and FX Processors Video Editing Stations Multimedia Presentation Room

Multimedia Systems and Applications3 Swtichers/Routers/DA’s Distribution Amplifier (DA) Split one input signal to two or more outputs Matrix Switch (AKA Routing Switcher) NxN cross bar circuit switch - analog or digital Can switch several signals (e.g., video+audio-left+audio-right) One input can be routed to multiple outputs Bandwidth 256x routing switcher requires 70 Gbs (i.e., 270 Mbs per source) 256x256 ATSC routing switcher requires 384 Gbs (i.e., 1.5 Gbs per source)

Multimedia Systems and Applications4 Timing/Clocks Timebase Correctors (TBC) Small timing errors introduced by VTR/VCR Caused by instability in mechanical scanning TBC reconstructs signal to remove errors Synchronize video signal from two sources Remember synchronous signal -- how to switch between two signals Use a master clock to provide sync pulse for all equipment Sometimes introduce single frame delay buffer for remote source

Multimedia Systems and Applications5 Film/Video Transfer Telecine - transfer film to video tape Typical output is 24 fps sequences Edit using 24 fps representation Optical printer - transfer video tape to film Transfer 25/30 fps video material to 24 fps film (inverse 3:2 pulldown) Many applications use multiple formats Incorporate material from video, film, and computer sources

Multimedia Systems and Applications6 3:2 Pulldown 24 fps to 30 fps (60 fields/sec) Add one video frame every 4 film frames Conversion process Video (Fields)Film V1 (F1+F1) F1 V2 (F2+F2) F2 V3 (F2+F3) F3 V4 (F3+F4) F4 V5 (F4+F4) - Inverse 3:2 pulldown reverses the process Used when encoding video material that is originally film

Multimedia Systems and Applications7 Video Production Switcher Produce high quality visual images N input streams and 1 output stream On-line live events and off-line post-production Special effects Titles, transitions, picture-in-picture, chromakey, … Implementation Conventional solutions use custom-designed hardware Modern approaches using software

Multimedia Systems and Applications8 Examples

Multimedia Systems and Applications9 Compositing

Multimedia Systems and Applications10 Video Editing Station production switcher edit deck source deck computer Linear Editor Non-linear Editor A/B Roll Editor operator’s console control interface GUI Interface