1. High Definition Video In The Real World
by: Don Schultz
Technical Principal
The Boeing Company

2. Proliferation of High Definition (HD)
SDTV sales have nearly disappeared
LCD HDTV sales in 2010 expected to exceed 170 million (over 200 million HDTVs total?)
HD programming exceeds 50% of total broadcasts in some areas
There are HD alternatives for almost every channel
Content quality not always consistent with true HD
HD Technology becoming nearly ubiquitous
3D building momentum & UHD on horizon

3. HD’s Market Hype vs True Value
Had HDTV in our home for almost 5 years
Were finding HDTV in more hotels, restaurants, bars, etc. every day (love it!)
However, market pressure is also pushing the technology into other environments like aircraft where weight, power and space are critical factors and where HD could place a greater demands on limited resources

4. High Definition (HD) 101 3 basic HD formats – 720p, 1080i & 1080p
480p = 480 vertical lines progressive scan
Not HD – but the standard DVD format in the US.
720p = 720 vertical lines progressive scan
1080i = 1080 vertical lines interlaced
1080p = 1080 vertical lines progressive scan
720p & 1080i are the most common formats for HDTV broadcasting
1080p is currently the highest quality format
used on Blu-Ray discs and some cable networks
Not yet commonly used for HDTV broadcasting

5. HD Aspect Ratio
High definition video formats 720 & 1080 conform to a 16:9 aspect ratio
1280 pixels horizontal x 720 pixels vertical
1920 pixels horizontal x 1080 pixels vertical
16:9

6. HD Pixel Count
1920x1080 refers to pixel dimensions – not resolution
Total number of pixels per each format are fixed
480: x 480 = ,600 pixels
720: x 720 = ,600 pixels
1080: x 1080 = 2,073,600 pixels
1920
16:9
1280
1080
720

7. Pixel Density Pixel Density Determines Resolution & Is Not Fixed
Varies With Display Size And Is Measured in Pixels Per Inch (PPI)
PPI = # Diagonal Pixels / Diagonal of Display in Inches
Dp = # of pixels
Di = Distance in inches
Note: Can use the Pythagorean
Theorem to find both

8. Sample Pixel Densities (Dp/Di = PPI)
Sample Calculations For 720p
9 In: Pixels / 9 Inches = ~ 163 PPI
11 In: Pixels / 11 Inches = ~ 134 PPI
15 In: Pixels / 15 Inches = ~ 98 PPI
23 In: Pixels / 23 Inches = ~ 64 PPI
Sample Calculations For 1080p
9 In: Pixels / 9 Inches = ~ 245 PPI
11 In: Pixels / 11 Inches = ~ 200 PPI
15 In: Pixels / 15 Inches = ~ 147 PPI
23 In: Pixels / 23 Inches = ~ 96 PPI

9. Human Vision
In Ophthalmology, normal “20/20” visual acuity is the ability to recognize letters on the Snellen chart when they subtend 5 minutes of arc.
Under ideal test conditions, a person may be capable of resolving two pixels separated by as little as .5 arc-minutes (~.008 deg) of angle.
The human eye does even better with lines.

10. Human Vision (cont.) Resolving Video Images
The human eye’s ability to resolve detail in an image (visual acuity) is directly proportional to the size of the elements of the image and inversely proportional to distance from those elements.
The objective is to find the optimum viewing distance for maximum image resolution without revealing pixel detail

11. Viewing Distance
Screen Width (SW)
Viewing Distance (VD) = SW x 2
Viewing
Angle
Rule of thumb for distance is twice the width of display

12. Determining Viewing Angle
Example viewing numbers using a 23 inch display:
Screen width (sw) = ~19.5 inches
Viewing distance (vd) = ~39 inches
Viewing angle = ~28 degrees
Compare Viewing Distance With Graphic Display Tool – Next Slide

13. Equivalent View – Display Size vs Distance

14. Video Quality in the Real World
Real world image quality is highly subjective and depends upon many factors including:
Pixel Count or Dimensions (HD or SD)
Pixel Density
Dot Pitch of Display
Gate to gate display response time
Quality of Processing & Filters (codecs, deblocking, deinterlace, etc)
Displays Spatial & Spectral Resolution
Contrast (fragile)
Color calibration
Brightness (Luminance)
Visual Acuity of Viewer
Ambient Light
Viewing distance
Resolution & Quality of Original Video

15. HD on Smaller Displays? This is a key question with no easy answer
Evaluating the quality of HD video on smaller displays is difficult, subjective and leads to more questions for some…
In what HD format is the visible quality lost on smaller displays?
Is most of the HD quality lost on highly compressed, low bit rate video?
Is the trade-off between the quantity of SD titles on the server and a marginal improvement in quality from HD content worthwhile?
If there is no perceived visual benefit, is the marketing value of HD enough?

16. HD Video Demonstration & Q&A
Objective: compare HD formats and bit rates side by side
Videos encoded with SMPTE VC-1
Encoded in 420p, 720p and 1080p formats at 24fps
Continuous Bit Rate – 2 Pass - Main Profile
Available in bit rates from 500kbps to 6mbps
3 Display Sizes – 11 inch, 15 inch and 23 inch
11 inch – 1280x768 LCD (industrial display)
15 inch – 1920x1200 LCD (Dell laptop)
23 inch – 1920x1200 LCD (Sony SDM-P234)
Note: Video quality is EXTREMELY subjective and affected by many factors including viewing conditions.
Bottom Line…You’re The Judge!