Understanding Video

 Video Formats  Progressive vs. Interlaced  Video Image Sizes  Frame Rates  Video Outputs  Video as Digital Data  Compression  Tape Formats

 NTSC  NTSC-J  PAL  PAL-M  SECAM

 525 scanlines to a frame of video  Displays at 30 fps  Countries using NTSC  North and Central America  Philippians  Twain

 Same as NTSC but used in Japan  525 scanlines  30 fps  Darker black than NTSC  Black setting goes to 0 vs 7.5 IRE

 High resolution – 625 scanlines per frame  25 fps  Used in Europe, Scandinavia, the Pacific and South Africa

 Used in Brazil  525 scanlines  PAL color palette  Runs at 30 fps

 625 scanlines  25 fps  PAL color palette  Used in France, Russia, the Middle East and North Africa

 PAL  Sharper Image with 625 scanlines  More flicker because it runs at 25 fps  NTSC  Less flicker running at 30 fps  Poorer resolution only 525 scanlines

 Which should you use?  Depends on where your video will be viewed.  If America – must be NTSC  If Europe – must be PAL

 Video is made up of scanlines  When you display then from top to bottom in sequentially first line 1, then 2, 3,4, …….all the way to the bottom of the image. That is called Progressive scan and all computer monitors use this type of scan.

 When television first started they could not display video progressively.  They used fields  One field displayed all the even lines (2,4,6,8,…)and the other all the odd lines ( 1, 3, 5,7,...)  First they displayed the the even field and alternating with the odd field.  By weaving these together the could display a single frame.

 Computer use progressive but all televisions both NTSC and PAL use Interlaced display.  Interlacing by its nature photographs the odd numbered scanlines and then the even numbered scanlines.  Called Interlacing Artifacts

 Film is Progressive.  When you take an image with film you take the entire image at one time.  Advantage to progressive is better image quality.  Disadvantage is you can’t broadcast it. There is no broadcasting of progressive images excluding HD.

 Progressive  Entire image  Film or Computer screen  Better image quality  Interlaced  Every other line  Television  Broadcast compatibility  Whether shooting DV or broadcast the first shot are all the even lined fields and then the odd ones. Fields = Sam Lines Even and Odd Fields = Upper and Lower Fields

 FILM: 24 fps  PAL: 25 fps  NTSC: 30 fps

 DV  Digital Video  SD  Standard Definition Video  HD  High Definition Video

 DV  MiniDV  DVCPro-25  DVCAM  Image quality of each is the same.  Totally digital format

 SD  DVCPro-50 (digital)  Betacam SX (digital)  Betacam SP (analog)  DigiBetacam (digital)

 HD  HDV  DVCPro-HD (100)  HD

 All video is fixed in size  All are bitmapped video –there size is fixed at the moment they were created.  The sized of the screen makes no difference because the size of the image is fixed.

 Projected film and computer monitors are variable size.  If you project a film on a large screen or computer monitor you see more detail.

 Video resolution is fixed at 72 dpi.  DV – NTSC  720 x 480  PAL  720 x 576

 SD  NTSC – 720 x 486  PAL – 720 x 576

 Why?  NTSC  SD 720 x 486  DV 720 x 480  Both 720 and 480 are divisible by 4  Video compression requires 4 x 4 pixel squares called Super Blocks

 Comes in both progressive and interlaced formats.  There are three sizes.

 HD 480i & p  Broadcast image size  HD 720i & p  Refers to the number of vertical lines of information.  1280 x 720  HD 1080i  1920 x 1080

 All HD formats are 16:9 (16 units wide by 9 units high)

 1440 x 1080 – native format  JVC – 1280 x 720 p  Sony – 1920 x 1080i

 Summary  HD 1080i = 1920 x 1080  HD 720p = 1280 x 720  Traditional = 720 x 480

 Number which describes the relationship of the width of a picture with the height of a picture.  The height is described as the number one and the width describe how much longer than one unit high the picture is wide.

 To compete with TV, film started changing the aspect ratio to provide a different viewing experience.  Television invented with a 4 by 3 aspect ratio.  Pre-1950s films were 4:3 (1.33:1)

 Disney cartoons became (1.66:1) about 60% wider than high  Movies today are 16:9 (1.78:1)  Epic movies are wider 2.35:1

 SD = 4:3  HD = 16:9 vs 4:3  Letterboxing  Adding black bars at the top and bottom of the screen to fit a 16:9 image onto a 4:3 screen.  Pillar boxing  Adding black to the sides of the screen to fit a 4:3 image to a 16:9 screen.

 Analog  Digital

ANALOGDIGITAL  Composite  Single nozzle, RCA plug or BNC  S-Video  4 pin plug that carries the color on different wires  Component  Highest analog connection labeled red, green and blue or Y, CR and CB  Firewire  A communications protocol that moves digital data  SDI  Carries digital data but works for both SD and HD pictures

EMBEDDED SDIAES/EBU  Most time you will use embedded audio  Be careful not to cross digital an analog audio input  Digital audio on a microphone connector – 3 pins

 VHS  Universal  Poor quality  Analog

 DV  DVCPRO-25 (Panasonic format)  DVCAM (Sony format)  MiniDV (about 20 companies)  Image quality between the three formats is identical.

 DVCPRO-50  Higher quality than DV (6 MB/sec data rate)  DVPRO-50 (50 MB/sec data rate)  6 MB/sec data rate  Used by most broadcast stations

 DVCPRO-HD (100)  HDV  DV tape size and data rate  HD picture quality  Brand new format  Betacam SX  See only in broadcast about the same quality as HDV

 Betacam SP  Industry workhorse for video formats the broadcast industry  Analog  Used around the world on daily basis for video capture and editing

 DigiBetacam  SD highest quality  16:9 or 4:3 ratio recording  Can shoot 24 fps as well as 30 fps or 25 fps  Digital  High end of standard definition

 HD  D1 & D5  Used specifically when high resolution is necessary  Work at the highest quality you can afford  Most people = DV  Broadcast industry = DigiBetacam