Chapter 6

Digital Television

Video Signal

Pixels Luma & chroma NTSC

525 scan lines 30 fps interlaced -- 60 fields 4:3 aspect ratio

Composite-lum & chrom combined Component-separated

Video Scanning Process

Video signal constantly changing Place/remove picture 30x/second Must be precise Vertical sync pulse--coordinates start of each new

frame or field Horizontal sync pulse--coordinates each individual

line

Control Components

Video signal requires components that keep signal synchronized and lessen interference Sync generator--creates a series of timing pulses

(“sprocket holes”) Process amplifier--stabilizes and amplifies video

& removes noise TBC--’repairs’ sync pulses

Cont...

Control Components

…cont... Frame synchronizer--syncs typically outside

signals to studio sync Color Bar generator--sends standardized

pattern of colors for calibration of video levels

Control Components

…Comparison... A frame synchronizer takes a digital “snapshot” of each incoming frame of video and releases immediately as the next frame comes in. Once converted to digital, the video frame can be blended with any other digitized video frame via transitional effects.

Now, how does the frame synchronizer in your digital mixer differ from an actual time-base corrector?

Control Components

They both work on the principle of converting incoming video from analog to digital. And they both stabilize the video picture so that their respective outputs can feed other equipment requiring digitally-stable signals

One time-base corrector job: It corrects inconsistencies of an analog playback VCR. It accomplishes this by sampling one video scan line at a time (not an entire frame), corrects any instability by stripping the scan line of its old sync signal and replacing it with a brand new sync signal

Diagnostic Components

Waveform monitor--analyze & adjust luminance (audio uses VU)

Vectorscope--shows hue and saturation levels (chrominance)

CCU--adjusts the cameras output, such as video gain/ iris opening / white balance / black balance (pedestal)

Digital Video Basics

Bitstream--a stream of digital information, such as video (‘streaming audio/video’)

Transparent--no loss of signal quality as bitstream travels

Compression--lossy or lossless

Video Recording Principles

Helical scan / slant track Longitudinal tracks

Audio, control track Vs. AFM /hi-fi (editing problem)

Tape speed / writing speed Video heads

Time Code

SMPTE Vs. control track Time code generator VITC--time code pulses on the spaces

between the frames Longitudinal TC--”striping” --on unused audio

channel (add after)

Communication Technology

RTV 151

Multichannel TV ServicesAnd

Streaming Media

Chap. 7 - MVPD

Cable, DBS, Pay TV, IPTV (chap. 8) SMATV, MMDS, TVRO Pay TV

PPV, VOD, NVOD, SVOD

Cable TV

Started late 1940s Growth began in 1970s (HBO) Tree and branch architecture

Headend Reception from -- , conversion, channel assignment

Trunk Line Feeder lines Drop lines Backfeed lines amplifiers

Local geographic areas - but MSOs

Some Cable TV issues

A la carte Must carry / Class A LPTV must carry Franchising / IPTV -- statewide -- FCC Digital cable Telephony (VoIP) -- Skype, Vonage, Google Voice... High speed internet (slow down issue) Coax / copper wires / hybrid / all fiber Multicasting DTV channels

DBS issues

Location of satellites (dishpointer) Location of uplink facilities

DirecTV: Castle Rock, CO DISH: Cheyenne, WY

Local into local HD roll-out -- MPEG-4 AVC Satellites

Launching / How launched video / multiple dishes HD locals Alternative services

IPTV issues

Service locations FiOS vs. U-verse IPTV vs. cable vs. DBS vs. --- Internet

broadband 2-way benefits vs. other MVPDs Bundles -- benefits?

Chap. 8 - Streaming Media

How different from ITV (ch.9) / IPTV? Live streaming (watching a TV show); vs.

progressive download Limited number of users / vs. broadcasting Webcams are not considered streaming Live radio stations and live ‘TV stations’

Copyright issues (who owns what?) Original site or extra distribution outlet?

Established streaming platforms

Microsoft / Windows Media Player RealPlayer / RealProducer as encoder Apple QuickTime Apple iTunes Streaming sites

Livestream Ustream

Also... Macromedia/Flash -- technically a plug-in

Podcasting, etc.

RSS - really simple syndication ; not live streaming EV-DO -- Verizon’s Evolution Data Only Network --

‘V-cast’ wireless mobile video service (or ‘optimized)

Compare to mobile TV? (mDTV)

DVB example FiOS TV -- Verizon’s fiber optic to the home service

that offers broadband Internet, IPTV and phone service

AT&T’s U-verse IPTV service

Other terms and ideas…

Streaming architecture -- handles and synchronizes digital files: QuickTime, Flash…

Codec -- compression/decompression: a compression algorithm (or coder - decoder) A codec (the program) is not the coding or compression

format or standard – a format is the standard, a way of storing data; The codec is the program used to read or write such files.

Slivercasting -- cable channels, now … ISMA / interoperability -- Internet Streaming Media

Alliance

Other interactive TV issues

Internet TV connections vs. IPTV hulu.com, veoh.com, clicker.com ...

Streaming players: (comparison) Apple TV Roku Google TV Boxee

Sling Player / Sling box (‘TV anywhere’) UGC

Social issues

Who is using what type media? Teen and younger use of and access to

Predators? Subversion of parental roles? (webcams, online videos, social impact)

Loss of public service journalism Mobile media, new narrative conventions University and business training -- podcasts,

streams, online training and education

Legal issues

MPEG-21 --multimedia application open framework WRAL / CBS stream example DRM / also called TC

Technical standards / control of home environment Trusted Computing? Or Treacherous computing? What did the VCR allow? / not allow? (Betamax case)

Privacy MySpace / YouTube IP address ---> next --->

www.edonkey.com

The eDonkey2000 Network is no longer available. If you steal music or movies, you are breaking the law. Courts around the world -- including the United States

Supreme Court --have ruled that businesses and individuals can be prosecuted for illegal downloading.

You are not anonymous when you illegally download copyrighted material.

Your IP address is 129.7.92.172 and has been logged. Respect the music, download legally. ###