VIDEO TECHNOLOGIESVIDEO TECHNOLOGIES

Iwan Sonjaya,ST.MMT,MTIwan Sonjaya,ST.MMT,MT

Computer and Informatics Engineering Dept.Computer and Informatics Engineering Dept.State Polytechnic Of JakartaState Polytechnic Of Jakarta

Video TechnologiesVideo TechnologiesVideo TechnologiesVideo Technologies

ANALOG

DIGITAL

Analog Video TechnologyAnalog Video TechnologyAnalog Video TechnologyAnalog Video Technology Analog means ? Analog means ?

Analog Video TechnologyAnalog Video TechnologyAnalog Video TechnologyAnalog Video Technology

Analog Video TechnologyAnalog Video TechnologyAnalog Video TechnologyAnalog Video Technology

VideotapeVideotape

LaserdiscLaserdisc

Video (Analog Tape)Video (Analog Tape)Video (Analog Tape)Video (Analog Tape)PositivesPositives

Familiar, common hardwareFamiliar, common hardware VCRs, players, camcordersVCRs, players, camcorders

PerceivedPerceived image image ““qualityquality””Impact of screen sizeImpact of screen size

Full color depth (~ 24-bit)Full color depth (~ 24-bit)

Video (Analog Tape)Video (Analog Tape)Video (Analog Tape)Video (Analog Tape)PositivesPositives

RECORDABLERECORDABLE & erasable & erasable Inexpensive hardware & tapesInexpensive hardware & tapes Can be digitized Can be digitized

Video (Analog Tape)Video (Analog Tape)Video (Analog Tape)Video (Analog Tape)NegativesNegatives

Quality of NTSC Quality of NTSC (standard N. Am. television) (standard N. Am. television)

TV vs. MonitorTV vs. Monitor Fundamentally linearFundamentally linear

Hard to use segmentsHard to use segments ExampleExample(s)(s) Computer control ??Computer control ??

Video (Analog Tape)Video (Analog Tape)Video (Analog Tape)Video (Analog Tape)NegativesNegatives

Limited manipulationLimited manipulation Costly hardware to editCostly hardware to edit Quality loss by generationQuality loss by generation

Distance distribution Distance distribution Limited rapid sharingLimited rapid sharing cf. video conferencingcf. video conferencing

Analog Video Analog Video TechnologiesTechnologiesAnalog Video Analog Video TechnologiesTechnologies

VideotapeVideotape LaserdiscLaserdisc

(Laser videodisc) (Laser videodisc)

Laserdisc (Analog) Laserdisc (Analog) OverviewOverviewLaserdisc (Analog) Laserdisc (Analog) OverviewOverview

Precursor to DVD Precursor to DVD Advantages & DisadvantagesAdvantages & Disadvantages Laserdisc technologyLaserdisc technology Advanced systemsAdvanced systems

LaserdiscsLaserdiscs +/- AdvantagesAdvantages Higher video qualityHigher video quality Multi-channel soundMulti-channel sound Double-sidedDouble-sided Still frame & special effectsStill frame & special effects Potential for random accessPotential for random access

Non-linear = hyperNon-linear = hyper

Laserdiscs Laserdiscs +/- DisadvantagesDisadvantages ‘‘SpecialSpecial’’ hardware hardware

Unfamiliar at homeUnfamiliar at home BulkyBulky Cost of hardware Cost of hardware

vs VCR (or DVD)vs VCR (or DVD) No local recordingNo local recording

Video TechnologiesVideo TechnologiesVideo TechnologiesVideo Technologies

ANALOG

DIGITAL

VideoVideoVideoVideo

Video, like sound, is recorded and played Video, like sound, is recorded and played an as analog signalan as analog signal

Analog video must be digitized in order for Analog video must be digitized in order for it to put into a multimedia fileit to put into a multimedia file

Digital video has many advantages, but file Digital video has many advantages, but file size is importantsize is important

VideoVideoVideoVideo Several elements determine file size:Several elements determine file size:

Frame rateFrame rateImage sizeImage sizeColor depthColor depth

To determine file size use the following To determine file size use the following formula:formula:Frames per second X image size X color Frames per second X image size X color

depth / 8 = file sizedepth / 8 = file size

Video Compression and Video Compression and EditingEditingVideo Compression and Video Compression and EditingEditing

There are two types of video compressionThere are two types of video compression

Lossless – preserves the exact image throughout Lossless – preserves the exact image throughout the compressionthe compression

Lossy – eliminates some of the data in the image Lossy – eliminates some of the data in the image (provides greater compression ratios than (provides greater compression ratios than lossless)lossless)

Remember – there is always a trade off, file size Remember – there is always a trade off, file size versus image qualityversus image quality

Video on the InternetVideo on the InternetVideo on the InternetVideo on the Internet There are two types of video transfer over the There are two types of video transfer over the

InternetInternet

HTTP (Hypertext Transfer Protocol) – HTTP (Hypertext Transfer Protocol) – downloads the entire video to the hard drive on downloads the entire video to the hard drive on the userthe user’’s computers computer

RTSP (Real-Time Streaming Protocol) – is a RTSP (Real-Time Streaming Protocol) – is a continuous-playing, streaming technology in continuous-playing, streaming technology in which the userwhich the user’’s computer is in constant contact s computer is in constant contact with the server playing the videowith the server playing the video

Video TipsVideo TipsVideo TipsVideo TipsColor depth

Reducing the color depth to less than 256 colors gives a markedly poorer-quality image.

Frame rate

Reducing the frame rate to less than 15 frames per second causes a noticeable and distracting jerkiness that is usually unacceptable.

File size A technique for reducing file size is to minimize the use of video in the image that appears on the screen – that is, to create video only for the parts of an object that are changing, such as a flickering candle. The video could be played over and over to create the motion of a flickering candle.

Video TipsVideo TipsVideo TipsVideo TipsDisplay size In most multimedia titles, you do not need

to show full-screen video. The video can be played in a window that can be as small as one-fourth or even one-sixteenth the size of the screen.

Conclusion: Changing the image size and compressing the file become the primary ways of reducing file size. In most cases, a one-quarter screen image (320 X 240), an 8-bit (256 colors) color depth, and a 15 frames per second frame rate are acceptable in a multimedia title.

Digital VideoDigital VideoDigital VideoDigital Video

What is it?What is it? Most commonly:Most commonly:

Analog video – Analog video – digitizeddigitized Computer filesComputer files

Newer technology:Newer technology: Original digital video (DV)Original digital video (DV) Bits on a Bits on a digital tapedigital tape

Creating Digital VideoCreating Digital VideoCreating Digital VideoCreating Digital VideoHardwareHardware AnalogAnalog Digitizing GearDigitizing Gear

$50 - $1000+$50 - $1000+ Internal, external, bothInternal, external, both

Digital camcorder + IEEE 1394 Digital camcorder + IEEE 1394 ““FirewireFirewire”” or or ““i Linki Link””

Many digital Many digital ‘‘stillstill’’ cameras cameras Highly variable resultsHighly variable results

PC / web cameras (PC / web cameras (““golf ballsgolf balls””))

Creating Digital VideoCreating Digital VideoCreating Digital VideoCreating Digital VideoSoftwareSoftware Comes with hardwareComes with hardware Capture, then editCapture, then edit

Not necessarily same softwareNot necessarily same software Varied features, e.g. formats Varied features, e.g. formats Varied learning curveVaried learning curve

Match to need & skillMatch to need & skill iMovie / Movie Maker to PremieriMovie / Movie Maker to Premier

Other Digital Video SourcesOther Digital Video SourcesOther Digital Video SourcesOther Digital Video Sources Clip video (CD / Web)Clip video (CD / Web) Download from web sitesDownload from web sites

Varies by video formatVaries by video format ““Screen captureScreen capture”” software software

CamtasiaCamtasia, , CamStudioCamStudio, etc., etc. Morphing softwareMorphing software Animation software Animation software

FlashFlash, et al – beyond our scope, et al – beyond our scope Class web page has linksClass web page has links

Digital Video ConceptsDigital Video ConceptsDigital Video ConceptsDigital Video Concepts Video = Video = ““framesframes””

How many / sec?How many / sec? Apply still image fileApply still image file

size concept size concept Video = ++MBVideo = ++MB

Forget KB Forget KB

Digital Video ConceptsDigital Video ConceptsDigital Video ConceptsDigital Video Concepts Image Size (Image Size (‘‘windowwindow’’ on screen) on screen)

Pixel dimensionsPixel dimensions Common SizesCommon Sizes

160 x 120 (160 x 120 (‘‘1/161/16’’)) 320 x 240 (320 x 240 (‘‘1/41/4’’)) 640 x 480 (640 x 480 (‘‘fullfull’’ screen) screen) 720 x 480 (DVD, 720 x 480 (DVD, ‘‘widerwider’’ screen) screen) What does a viewer really see?What does a viewer really see?

Digital Video ConceptsDigital Video ConceptsDigital Video ConceptsDigital Video ConceptsDV File Size FactorsDV File Size Factors Image pixel dimensionsImage pixel dimensions

Just like still imagesJust like still images FPSFPS

Frames per secondFrames per second Number required?Number required?

Color depth (bits)Color depth (bits) Increasingly, no optionIncreasingly, no option

Digital Video ConceptsDigital Video ConceptsDigital Video ConceptsDigital Video ConceptsDV File Size FactorsDV File Size Factors Video (file) format (more later)Video (file) format (more later)

QuickTime / AVI / WMVQuickTime / AVI / WMV MPEG (mpg)MPEG (mpg) StreamingStreaming

CODECCODEC Compression / decomp algorithmCompression / decomp algorithm Sometime selectable (cf. audio)Sometime selectable (cf. audio)

Audio qualityAudio quality Limited impactLimited impact

Digital Video Digital Video BenefitsBenefitsDigital Video Digital Video BenefitsBenefits Inexpensive hardware to createInexpensive hardware to create Edit electronically withEdit electronically with

software (non-linear editing) software (non-linear editing) Just another (large) file = Just another (large) file =

transmission potential transmission potential FTP, email, or on web pagesFTP, email, or on web pages Keep file size down!Keep file size down! Or Or streamstream it it

More flexible useMore flexible use

Digital Video Digital Video IssuesIssuesDigital Video Digital Video IssuesIssues Image quality (e.g. jaggies)Image quality (e.g. jaggies) Limited resizing (pixels, jerky)Limited resizing (pixels, jerky) Differing formats / architecturesDiffering formats / architectures Non-standard compression schemesNon-standard compression schemes

Broadway AVI & M-JPEGBroadway AVI & M-JPEG Codec compatibility / availabilityCodec compatibility / availability

Storage requirements / downloadsStorage requirements / downloads

Impact of File SizeImpact of File SizeImpact of File SizeImpact of File Size 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

1 min video can take minutes to download

DV FormatsDV FormatsDV FormatsDV Formats QuickTime (mov)QuickTime (mov)

Background / compatibilityBackground / compatibility Video for Windows (avi)Video for Windows (avi) WMVWMV MPEG (mpg, mp#)MPEG (mpg, mp#)

Current standard ?Current standard ? Video CD / DVDVideo CD / DVD

Streaming competition (later)Streaming competition (later) Real vs MS vs QTReal vs MS vs QT

‘‘ExoticExotic’’ DV DV‘‘ExoticExotic’’ DV DV VCD (Video CD)VCD (Video CD)

Mpeg-1 Mpeg-1 Common outside USCommon outside US

QTVRQTVR Lighthouse (HS)Lighthouse (HS) Orlando Art MuseumOrlando Art Museum

Other DigitalOther Digital Video Topics Video TopicsOther DigitalOther Digital Video Topics Video Topics Creating digital videoCreating digital video

CapturingCapturingEditingEditingProducing Producing

DVDDVD StreamingStreaming