Introduction to Video: Terms and Concepts

Here is a list of things covered during my first class session of Film for Education Technologists:

  • Video production can be categorized into two main, professional levels:
    • “Full Production,” which consists of a large crew, elaborate sets and lighting, and a large budget (>$250,000).
    • “Corporate Video Production,” which typically consists of a small crew (2-4 people), available light supported by portable lighting equipment, smaller budget ($15,000 or less).
  • The illusion of motion:
    • The Phi Phenomenon—a series of still pictures flashed in succession appear to be in motion.
    • Persistence of Vision—makes the blank spake between  rapidly moving images disappear so the images appear to blend together into fluid motion.
  • The Video Image
    • Frames—like film, video is made up of a series of still images played frame by frame.
    • Fields—Each digital frame is made up of a number of lines.  (Standard Def = 480 lines/frame).  However, to create a better illusion of motion, each frame is divided into two interlaced segments called fields.  So there are two fields of 240 lines each in a single frame.  That’s why when you scan frame by frame, it seems like you see the exact same image twice, when in reality you are first seeing the odd lines, then the even lines.
    • Resolution (sharpness of detail)—you can always view down in resolution, but you can never really view an image (or series of images) in resolution better than the source material.  The current best capture resolution is Red Camera (4k or 2304×4096).

Resolution comparison graphic

  • Video Broadcasting Standards
    • Standard Def = 48oi (interlaced)
    • 720p = Scaled down version of Hi-Def. It has 720 lines/frame, progressively scanned (no fields). Used for DVD and broadcasting motion pictures.
    • 1080i = 1080 lines interlaced (540p), yet it looks more natural to the eye than 720p.  This is the standard for true HD television.
    • 1080p = 1080 lines, progressive scan. This is called True Hi-Def.
  • Video Standards
    • NTSC (National Television Standards Committee)—American TV standard (480i at 30 frames/sec)
    • PAL & SECAM—Other countries use these standards. Not compatible with NTSC. So, if you are filming abroad or for a foreign country, be sure you are selecting the appropriate standard. (Or at least can transcode correctly.)
    • HDTV (High Definition television)—1080i at 30 frames/sec.
  • Aspect Ratios
    • 16:10—also known as 8:5, is an aspect ratio mostly used for computer displays and tablet computers. The width of the display is 1.6 times its height. This ratio is close to the golden ratio “\varphi” which is approximately 1.618. LCD computer displays using the 16:10 ratio started to appear in the mass market from 2003. By 2008 16:10 had become the most common aspect ratio for LCD monitors and laptop displays.[1] Since 2010, however, 16:9 has become the mainstream standard, driven by the 1080p standard for high definition television.
    • 16:9 standard—(1.77:1) (16:9 = 42:32) is an aspect ratio with a width of 16 units and height of 9. Since 2009, it has become the most common aspect ratio for sold televisions and computer monitors and is also the international standard format of HDTVFull HD, non-HD digital television and analog widescreen television (EDTVPALplus. Many digital video cameras have the capability to record in 16:9, and 16:9 is the only widescreen aspect ratio natively supported by the DVD standard. DVD producers can also choose to show even wider ratios such as 1.85:1 and 2.39:1[1] within the 16:9 DVD frame by hard matting or adding black bars within the image itself. Some films which were made in a 1.85:1 aspect ratio, such as the U.S.-Italian co-production Man of La Mancha, fit quite comfortably onto a 1.77:1 HDTV screen and have been issued anamorphically enhanced on DVD without the black bars.
    • 4;3 standard—(1.33:1) (generally read as “Four-Three”“Four-by-Three”, or “Four-to-Three”) for standard television has been in use since the invention of moving picture cameras and many computer monitors employ the same aspect ratio. 4:3 was the aspect ratio used for 35 mm films in the silent era and is used today for film production under the name Super 35. It is also very close to the 1.375:1 aspect ratio defined by theAcademy of Motion Picture Arts and Sciences as a standard after the advent of optical sound-on-film. By having TV match this aspect ratio, movies originally photographed on 35 mm film could be satisfactorily viewed on TV in the early days of the medium (i.e. the 1940s and the 1950s). When cinema attendance dropped, Hollywood created widescreen aspect ratios (such as the 1.85:1 ratio mentioned earlier) in order to differentiate the film industry from TV.
    • 2.21:1—A NTSC DVD video stream is 720×480 (1.5:1), which is an impossible aspect ratio for a movie. So, each MPEG-2 Video stream has a DAR (Display Aspect Ratio) flag. The flag tells the player for what kind of target display the stream has been encoded. There’s 4 values: 1:1, 4:3, 16:9 and 2.11:1. The first and last one are not terribly important since there’s no TVs having these aspect ratios. (e.g Old Boy Fight Scene looks better in the 2.21:1 DAR.) Most compressors will typically apply one of three solutions for adjusting to fit a 4:3 or 16:9 TV standard:
      • Adding mattes
        • Letterboxing (WS –>SD; adding black bars to top and bottom),
        • Pillarboxing (or reverse letter boxing adds black bars to sides to make video fit on a wider screen.)
      • Anamorphic (squeezing 1.5:1 into 4:3)
      • Pan and Scan (4:3 Hell for viewers!)
    • Common Cinematic Aspect Ratios:
      • 1.85:1, 2.35:1 (“scope” between 1958-1970) otherwise know today as 2.39:1 and 2.40:1—Some directors like to shoot in 1.85, the standard widescreen cinema format, while others prefer 2.35. Some prefer a mix.

Aspect Ratios

Some common aspect ratios
1.33:1 (4:3)
Old television & computer monitor standard
1.41:1
Lichtenberg ratio 1:√2 ~1:1.4142, ISO 216paper sizes (A4)
1.5:1 (3:2)
Classic 35 mm film
1.6:1 (8:5)
(Credit cards are 85.6 × 54 mm which is ~1.59:1)
1.618:1
The golden ratio
1.66:1 (5:3)
A common European widescreen standard; native Super 16 mm film.
1.77:1 or 1.78:1 (16:9)
HD video standard. Most consumer camcorders shoot in this DAR.
2.39:1 or 2.40:1
A current widescreen cinema standard
  • Safe AreaTVs made between 1950-70 varied in how much of the image they showed.  As a result broadcasters created “safe areas.”  These displays can be toggled on more expensive cameras.  Others just show the following safe areas:
    • Overscan—Crop around the image to display only what the home TV will see.
      • Title Safe area
      • Action Safe area
    • Underscan—Display the entire video image.

Overscan_examples.svg (1)

  • Camera and Videotape formats:
    • Increasingly, video is being produced in a tapeless environment.  This means, no more physical copies lying around film houses.  Everything is being captured on image cards or other digital storage devices.  Most consumer camcorders capture to standard SD cards.
    • The video format history of NTSC includes the following mediums: VHS, 3.4 (Umatic), Betacam/MII, MiniDV, DVC Pro/DV Cam, Digital Betacam, etc.
Advertisements

About bryantanner

I'm obsessed with learning via the appropriate technology. My professional mission is to effectively deliver instruction to learners in a way that yields the greatest results for all stakeholders involved.
This entry was posted in Uncategorized. Bookmark the permalink.

One Response to Introduction to Video: Terms and Concepts

  1. Pingback: Shane Hurlbut – Aspect Ratios for Your Story; A Response – Britt Moore

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s