Ed's AV Handbook.com
Home Theater & High Fidelity Stereo Audio


Chapter Four
Video Reproduction

Page 6

Batting practice for the audio/video pro and a primer for the novice 



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Television Resolution
UltraHD, High Definition, Enhanced Definition, Standard Definition, NTSC
          A television picture is initially defined in terms of video resolution.  Resolution refers to its vertical and horizontal detail.   Vertical resolution is the number of vertical transitions,
the number of horizontal lines, traced across the screen from top to bottom.  Horizontal resolution is the number of horizontal transitions; the number of pixels that make up each horizontal line. 

NTSC  
         NTSC TV was comprised of up to 525 lines of vertical resolution.  43 of the lines were used for technical data that included the horizontal & vertical synchronizing signals. That left a balance of up to 482 lines for the image.
          However the NTSC analog system did not produce all 482 lines sequentially or progressively.  Instead NTSC used an
interlaced method of two alternating fields to compose one picture frame.
          The first field traced the odd numbered lines in 1/60th
of a second.  The second field traced the even numbered lines in the next 1/60th
of a second.  That built the entire picture in a total of 1/30th of a second; fast enough for the brain to perceive it as a complete frame.
          As stated, NTSC offered up to 482 lines of vertical resolution.  However,
the vertical resolution varied as interlaced scenes transitioned from one to another.  For example, a transition from an all black picture frame to an all white frame reduced the vertical resolution to 241 lines.  NTSC could only produce all 482 lines during a still picture frame.
          As explained, NTSC vertical resolution was determined by video interlacing.  On the other hand its horizontal resolution was determined by the video source.  For example, a DVD offers the best NTSC horizontal resolution of 720 pixels per line.  The Laser Disc had a horizontal resolution of 400 pixels; VHS videotape 240 pixels.

SDTV
          Standard Definition digital TV has a vertical resolution potential of up to 480 interlaced lines. Therefore, SDTV retains the same vertical resolution issues as NTSC.  But the absence of analog “noise” is an improvement over NTSC.   SDTV horizontal resolution ranges from 640 to 704 pixels per line.

EDTV
          Digital Enhanced Definition TV is a significant improvement over NTSC and SDTV. EDTV offers a fixed vertical resolution of 480 lines with 704 pixels per line.  Vertical resolution is fixed because EDTV traces the video progressively line by line.  EDTV eliminates interlace issues.   

HDTV
          High Definition Television has two broadcast resolution options:
                 -  720p by 1280
@ 60 frames per second (fps) with a 16:9 picture ratio.
                 -  1080i by 1920
@ 60 fps with a 16:9 picture ratio.

           720p (progressive) has a vertical resolution of 720 lines with a horizontal resolution of 1280 pixels per line at 60 fps. 
        1080i (interlaced) results in a vertical resolution ranging from 540 to 1080 horizontal lines with a horizontal resolution of 1920 pixels per line at 30fps.
          For broadcast the number of pixels per second is almost indistinguishable.  However sports broadcasters have favored 720p because it eliminates interlacing artifacts.
           Non-broadcast HD 1080p sources -- the BluRay video disc, hard drive media, and Internet services -- also eliminate the interlaced issue.  
In additon all HDTV sources offer a broader palate of color than NTSC, SDTV or EDTV.  

Ultra-HD
          Ultra-HD TV increases video resolution to
 2160 progressive lines (not interlaced) by 3840 pixels per line @ 30fps, 60fps, or 120fps with a 16:9 aspect ratio.  More significantly, Ultra-HD also expands the picture color gamut. 

DCI 4K 
 
           Some continue to refer to UltraHD as 4K.  Ultra-HD is not 4K.   4K defines the DCI commercial theater standards.
           -
4K DCI  2.39:1  aspect ratio =  1716  lines by 4096 pixels per line.
         - 4K DCI  1.85:1 aspect ratio  = 2160 lines by 3996 pixels per line.


HDR Ultra-HD
          High Dynamic Range (HDR) UltraHD is the most significant video improvement since the introduction of color.  However, it is offered in several formats.  And that is a problem.   Many current UltraHD TVs do not support all formats.  This issue is discussed later in this chapter.  The following links from Ed's AV Blog page also discuss Ultra-HD issues.

                          Link 1 - HDR UltraHD Part 1 thru 7 covers the HDR in detail.
                          Link 2 - Ultra-HD Risky Crossroad is not HDR specific.  
                                          But its offers a base for discussing UltraHD in general.


UltraHD Prerequisites
            There are are three prerequisites for a UltraHD home video system.  Their absence will lead to compromised performance or worse a blank screen.  This topic is also discussed in more detail later in this chapter.
 
1. HDMI 2.0, 2.0a, 2.0b, & 2.1
All system components must include at least HDMI 2.0 or 2.0a inputs &/or outputs.
  - HDMI 2.0 supports 2160p at 60 frames per second with up to 10 bit or 12 bit color.
  - HDMI 2.0a adds support for high dynamic range formats
  - HDMI 2.0b adds support for the HLG HDR format.
  - HDMI 2.1 more HDR support plus 48 Gbs bandwidth

Many early UltraHD TVs and video components are limited to HDMI 1.4 @ 30  fps, which will not deliver the potential of UltraHDTV. 
  

2. HDCP 2.2  
(High-bandwidth Digital Copy Protection)
All system components must support for HDCP 2.2.  
Many AV receivers, and early UHD TVs lack HDCP 2.2 support.  
Some only include one HDMI 2.0 input with HDCP 2.2. support.


3. MPEG HEVC
All UltraHD broadcasts receivers and Blu-ray players must support
HEVC compression.

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Ed's AV Handbook.com
Batting Practice for the AV Pro and a Primer for the Novice.
Copyright 2007 Txu1-598-288   Revised 2018