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About Video

Computer Screens

(Width x Lines)
  • 640x480 (VGA)
  • 852x480 (WVGA) Wide VGA - Typically used by HDTVs
  • 800x600 (SVGA) Super VGA
  • 1024x768 (XGA)
  • 1280x768 (WXGA) Wide XGA
  • 1280x1024 (SXGA)
  • 1600x1200 (UXGA)
  • 1920x1200 (WUXGA) Wide UXGA




DVD Notes


DVD World Zones

  1. U.S., U.S. Territories, Canada, and Bermuda
  2. Japan, Europe, South Africa, and the Middle East, including Egypt
  3. Southeast Asia, East Asia, including Hong Kong
  4. Australia, New Zealand, Pacific Islands, Mexico, Central America, South America, and the Caribbean
  5. Former Soviet Union, Indian subcontinent, Africa, North Korea, and Mongolia
  6. China

DVD Video Size - ```Video is stored on a DVD in 4:3 or 16:9 format in 4.3 frame size (see Anamorphic below). DVD players can typically output video in four different ways:```
  • Full frame (4:3 video for 4:3 display) 
  • Letterbox (16:9 video for 4:3 display) - black bars (mattes) on top and bottom
  • Pan & scan (16:9 video for 4:3 display) - picture has sides chopped off to fit TV
  • Wide screen (16:9 video for 16:9 display) - picture stored horizontally squeezed (Anamorphic) and played expanded on a 16:9 display with no loss of pixels

Official Internet DVD FAQ for the rec.video.dvd Usenet newsgroups



Aspect Ratios


TV sets
  • 1.33:1 (4:3) - Standard TV ratio
  • 1.78:1 (16:9) - Widescreen TV and HDTV Sets. A compromise between Academy (1.33:1) and CinemaScope? (2.35:1). Widescreen TVs are 33% wider than standard TVs and 33% narrower than CinemaScope
  • Other
    • The Apple Mac Cinema Display has a 16:10 ratio at 1920x1200

Film Type

  • Standard 16mm - 1.33:1 (4:3) in size suitable for transfer to standard TV.
  • Super 16mm - 1.66:1` in size so suitable for transfers to TV and HDTV.
  • 32 mm - 1.33:1 in size (Academy). Good for transfers to most cinema sizes, TV and HDTV.
  • Super 35 mm - 2.35:1 in size. Extra width provides ability to transfer to Cinemascope.
  • 70mm - about 1:2.2 in size. Twice as wide as 35mm, and uses 5 perfs per frame (4 for 32mm). There is no squeezing of the image required.
  • Film frame rate is 24 frames / sec
  • Most animators (but not Disney I'm told) create 12 frames per sec and duplicate to get 24 f/s.

Final Aspect Ratios

  • 1.33:1 - Standard TV aspect ratio called Standard, full frame or Academy frame. First used by Hollywood silent movies in the early 1930s.
  • 1:37:1 - In 1931 Academy aperture became the standard aspect for movies by masking the top and bottom of the 1.33:1 image.
  • 1.66:1 - Popular with animated features and European films.
  • 1.77:1 - Cinema standard very close to 16:9 Widescreen. eg. Toy Story.
  • 1.78:1 - Widescreen TV and HDTV ratio. eg. Finding Nemo.
  • 1.85:1 - Popular American Flat standard.
  • 2.35:1 - Studios used Anamorphic Cinemascope (and later the cheaper Panavision) to film wide image onto standard Academy 32mm film.
  • Other aspects...
  • Movie Theater tech...
  • Most movie theaters today use Academy sized 32mm film and use soft or hard matte to letterbox the film.
  • Audio is ecoded as wiggly lines on the side of the frame. A light and sensor decode it.
    • Audio pre 1977 - Audio track was mono.
    • Dolby Labs came up with two wiggly lines and eventually encode multiple speakers.
    • Dolby went Digital using the space between the left sprockets. Again a light and sensor read the info.
    • Sony Dynamic Digital Sound (SDDS) puts the audio on the strips down both edges of the film.
    • Digital Theater Sound (DTS) uses a machine readable time code encoded down the edge of the picture. 2 CDs hold the sound and stay in sync with the time code.
    • 70mm film uses magnetically stored sound (like tape).
    • Read the article...



Matted Vs Anamorphic


What is Matting?

Most films were shot in Academy aspect ratio (1.33:1). With Soft Matting they masked the top and bottom of the film while being projected. Less commonly done Hard Matting masked the top and bottom during filming (so film frame contain black bars).

What is Anamorphic?

In 2.35:1 film a special anamorphic camera lens "squeezed" a wider image onto a standard-size film frame. A second anamorphic projector lens "unsqueezed" the image when projected.

The Anamorphic DVD (sometimes called Enhanced DVD) process is similar. Wide images are compressed into a 1.33:1 frame. When played back on a Wides Screen TV you see the full wide image with black bars. the quality is far better than using the matting process. But you must have a Wide Screen display. On a Standard Screen ever 4th horizontal line discarded.

Read the full story... (external link)


HD Video


Unfortunatley there are a number of competing HD DVD standards emerging

Microsoft are also pushing there own WMVHD standard


TV Formats


International Formats: More Info | World TV Stds
  • NTSC format: 525 lines, 60 Hz, North America and Japan
  • PAL format: 625 lines, 50 Hz, Australia, Europe, China etc (60Hz in Brazil)
  • SECAM format: 625 lines, 50 Hz, France, Iraq, Iran

DVD produces exactly 480 scan lines of active picture for NTSC and 576 for PAL. The extra lines contain sync pulses and other information, such as the Closed Captions.


US TV


NTSC: (National Television System Committee)
  • 525 lines, 29.97 interlaced frames per second (59.94 fields per second)
  • NTSC is often referred to as "Never Twice the Same Color."
  • VHS Tape is around 320x240 (interlaced)
  • Broadcast TV is around the 525 lines (interlaced)
  • Progressive scan DVD players output around 480 lines (most consumer grade players)

Standard NTSC TV
  • 640x480i - Standard definition TV, 480 lines interlaced
  • 640x480p - EDTV - Enhanced Definition TV, 480 lines progressive

ATSC: (Advanced Telvision Standards Committee)
  • US Digital 16:9 Wide Screen TV
  • 720x480i - HD 480i, 480 lines interlaced, 60 frames/sec
  • 720x480p - HD 480p, 480 lines progressive, 60 frames/sec
  • 1280x720p - HD 720p, 720 lines progressive, 60 frames/sec
  • 1920x1080p - HD 1080p, 1080 lines interlaced, 24 frames/sec
  • 1920x1080i - HD 1080i, 1080 lines interlaced, 60 frames/sec


Australian TV


Some OZ TV stats
  • Population: 19.8 million (UN 2003)
  • TV households: 7.1 million (2003)
  • Cable penetration: 880,000
  • Digital TV households 250 thousand (Q4-2003) DBA 
  • More stats...

PAL TV: (Phase Alternating Line) Developed by Telefunken in Germany
  • 625 lines (576 visible), 25 interlaced frames per second (50 fields per second)
  • By reversing the relative phase of the color components on alternate scanning lines, PAL avoids the color distortion common to NTSC reception. Easily remembered as "Peace at Last."

Australian DVB-T - Digital Video Broadcasting Terrestrial (50Hz)
  • Foxtel now transmits SD digital TV via cable
  • All HD TV is transmitted via terrestrial
  • HD is broadcast 16:9 widescreen + MPG2 AC3 encoded sound
  • 720x576i - SDTV, 576 lines interlaced (625 lines total)
  • 720x576p - HD 566p, 576 lines progresive (625 lines total)
  • 1280x720p - HD 720p, 720 lines progressive (750 lines total)
  • 1440x1080i or 1920x1080 - HD 1080i, 1080 lines interlaced (1125 lines total)



Projectors & Wide Screen


Most XGA projectors can display DVD 16:9 ok. Most SVGA projectors can often do only 420 lines of video (NTSC Wide Screen).



Lip Sync Problems


TECHNOLOGY NEWS - In movie theaters of yesteryear, it was not uncommon for the audio and picture to be out of synch, with the silver-screened actors mouths moving and sound coming a half-second or more later.

http://newsletter.eetimes.com/cgi-bin4/DM/y/egbh0Fyton0FrK0CUOd0AA
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