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									Future Media & Technology




     Display technology for professional
         and consumer applications

                   Richard Salmon
               BBC Research & Innovation




Research & Innovation       1
 Why the CRT is important to us in
 Television Production




Research & Innovation   2
 Why the CRT is important to us in
 Television Production
• The Cathode Ray Tube has defined the
  TV system for the past 70 years




Research & Innovation   3
 What are the alternatives to CRTs

• Rear projection




 Sagem 50” DLP: 1280x720




Research & Innovation      4
 What are the alternatives to CRTs

• Rear projection
• Front projection




 JVC D-ILA: 1920x1080




Research & Innovation   5
 Projection technologies




      One Chip:                   Three Chip:
       Compact, lightweight        Highest image quality
       Auto convergence            Highest efficiency
       Efficient                   Highest cost
       Lowest cost


Research & Innovation         6
 Projection technologies

                 Advantages
• High end products give accurate picture
  reproduction
                 Disadvantages
• Bulky (rear projection)
• Awkward (front projection)



Research & Innovation   7
 What are the alternatives to CRTs

• Rear projection
• Front projection
• Plasma (PDP)




 Pioneer 50” PDP:
 1365x768



Research & Innovation   8
 Plasma (PDP)




Research & Innovation   9
 Plasma (PDP)




Research & Innovation   10
 Plasma (PDP)

                  Advantages
• Excellent viewing angle
• Good colour rendition
                   Disadvantages
• Burn-in
• Motion rendition may be inadequate
• Requires greater bit-depth in blacks


Research & Innovation   11
 What are the alternatives to CRTs

•    Rear projection
•    Front projection
•    Plasma (PDP)
•    LCD


    Sharp 45” LCD: 1920x1080
    European model,
    with DTT receiver


Research & Innovation          12
 Liquid Crystal Display (LCD)




Research & Innovation   13
    Liquid Crystal Display (LCD)

                 Advantages
• Mass production brings rapidly falling costs
                   Disadvantages
•   Colour changes with viewing angle
•   Contrast changes with viewing angle
•   Poor grey-scale and colorimetry
•   Gamma curve very inaccurate near black
•   Motion rendition may be inadequate

Research & Innovation   14
 The Future?
• FED (Field Emission Display)
   – PFE (Printable Field Emitters)
• SED
  (Surface-conduction Electron-emitter Display)
   – Canon / Toshiba 42-inch prototype shown

           New implementations of old idea
         Pilot manufacturing starting for SED
             First products later this year
     Joint venture - but now transferred to Canon

Research & Innovation      15
 The Future?

• OLED (Organic Light Emitting Diodes)
  LEP (Light emitting polymers)
   – Starting in small-screen market
   – Production of several million displays
   – Philips shavers and Kodak cameras
   – Mobile phones, MP3 players
           Thin and potentially flexible
                    Larger?
                   Lifetime?
Research & Innovation      16
 The Future? - OLED
• Sony have a
  27-inch 1080p
  OLED HDTV
• Samsung have
  shown this 40-
  inch prototype
• Sony prototype
  11-inch OLED
  camera
  viewfinder
                        Source: Samsung Electronics

Research & Innovation           17
 Example of differences in technologies
Motion rendition on CRT




Research & Innovation     18
 Example of differences in technologies
Motion rendition on LCD with “always on” backlight




Research & Innovation    19
 Scanning or flashing backlight?
• Improved motion rendition




Research & Innovation   20
 Scanning or flashing backlight?
• Improved motion rendition
   but:
   - 50 Hz flash will cause flicker on large sceens
   - 75 Hz will have poor rendition of video
   - 100 Hz probably required - with motion
     interpolation?




Research & Innovation      21
 Example of LCD problems
• Transfer characteristic




             Measured transfer characteristic 1
Research & Innovation       22
 Example of LCD problems
• Transfer characteristic - stretch of blacks




             Measured transfer characteristic 2
Research & Innovation       23
 Example of LCD problems
• Transfer characteristic - stretch of blacks
   - causes increased visibility of noise in blacks
   - causes increased visibility of coding artefacts
   - sometimes dealt with by clipping the blacks




Research & Innovation      24
 LCD remaining problems
•   Transfer characteristic - stretch of blacks
•   Colorimetry
•   De-interlacing
•   Latency - 1 frame too much in production
•   Motion portrayal
•   24p or 25p judder in LCD viewfinder
•   8-bit DAC in the display panel - 7-bit performance
          So it is not immediately suitable
                as a Grade 1 Monitor!

Research & Innovation       25
 Why the CRT is important to us in
 Television Production




Research & Innovation   26
 Why the CRT is important to us in
 Television Production
  Although cameras and other acquisition
  technologies vary, the technical
  specification of the TV signal is, in
  practice, that which “looks right” on the
  Vision Engineer’s monitor
  (or the monitor in the grading suite)




Research & Innovation   27
 So the problem is…?

• Will the CRT continue as the reference?




Research & Innovation   28
 The CRT as reference

• Historically this has worked well, since
  the viewer in the home has also seen our
  pictures on a CRT.
• The physics of any one CRT is much the
  same as another




Research & Innovation   29
 The CRT as reference

• Historically this has worked well, since
  the viewer in the home has also seen our
  pictures on a CRT.
• The physics of any one CRT is much the
  same as another
                    OR IS IT?
     Gamma is 2.2 in NTSC countries,
                 2.8 in Europe

Research & Innovation   30
 Gamma

      Gamma is 2.2 in NTSC countries,
             2.8 in Europe…

         No, it’s probably about 2.35
  It’s just that we didn’t really know how to
     measure gamma at the time the specs
                 were written down
 So the real reference is indeed the CRT

Research & Innovation   31
 So the CRT remains the reference

            Does this mean that

     The Monitor must be a CRT?




Research & Innovation   32
 So the CRT remains the reference

            Does this mean that

     The Monitor must be a CRT?

      No, all it actually means is that

      The Monitor Spec remains
         essentially the same
Research & Innovation   33
 So why not stick to using the CRT?




Research & Innovation   34
 So why not stick to using the CRT?

               Good plan… but
•   Production spaces currently being built
    often assume the use of flat panels
•   Grade 1 CRT monitors are hard to find
•   Manufactures are not committing to CRT
    monitors in the long term
•   As we move to HD, CRT monitors are
    even harder to find

Research & Innovation   35
 What’s the new Grade 1 Monitor?




Research & Innovation   36
 What’s the new Grade 1 Monitor?
• It is unlikely that there will be a single
  dominant technology




Research & Innovation    37
 What’s the new Grade 1 Monitor?
• It is unlikely that there will be a single
  dominant technology
• If we can’t standardise on a single
  technology, can we standardise the signal
  interface format?

                              Studio
                          infrastructure

               Signal
              converter

Research & Innovation          38
 What’s the new Grade 1 Monitor?
What needs to be standardised:
• Signal representation:
    - Linear (like Plasma, DLP)
    - Gamma curve (like CRT, e.g. Rec.709)
    - S-curve (like LCD)

                              Studio
                          infrastructure

               Signal
              converter
                                           Signal converters
Research & Innovation          39
 What’s the new Grade 1 Monitor?
What needs to be standardised:
• Signal representation :
    - Linear (like Plasma, DLP)
    - Gamma curve (like CRT, e.g. Rec.709)
    - S-curve (like LCD)
• Colorimetry:
    - ITU Rec 709
• ...

Research & Innovation   40
 What’s the new Grade 1 Monitor?

• The CRT gamma, colorimetry, etc. forms the
  current standard
        If we change this reference
           it is a recipe for chaos




Research & Innovation   41
 What’s the new Grade 1 Monitor?

• The CRT gamma, colorimetry, etc. forms the
  current standard
        If we change this reference
           it is a recipe for chaos
          But the most important factor:
  The visibility to the eye of noise and
   quantising is equalised by gamma

Research & Innovation   42
 What’s the new Grade 1 Monitor?

SMPTE, EBU, ARIB and ITU all now studying
      how to define the reference display

• SMPTE Study Group chaired by David Bancroft
• EBU P/DISPLAY group chaired by Richard Salmon
• ITU to appoint Rapporteur for Gamma




Research & Innovation   43
 What’s the new Grade 1 Monitor?

SMPTE, EBU, ARIB and ITU all now studying
      how to define the reference display

• SMPTE Study Group chaired by David Bancroft
• EBU P/DISPLAY group chaired by Richard Salmon
• ITU to appoint Rapporteur for Gamma
 If you think it is important to get this right –
    then please contribute to these groups

Research & Innovation   44
 The work of EBU P/Display
• Defining the different classes of monitor
  we need
   – Reference - Grade 1
   – Control Room - Grade 2
   – Observation - Grade 3
   – Special categories
      • Viewfinders
      • In vision (studio set design)
      • On location and on the studio floor



Research & Innovation         45
 The work of EBU P/Display
• Defining the different classes of monitor
  we need
• Deciding what characteristics are important
     Luminance range, Black level, Contrast ratio, Gamma
     characteristic, Grey scale reproduction, Colour gamut,
     Reference white, Viewing-angle dependency, Motion portrayal,
     Resolution, Scaling, de-interlacing and overscan issues, Delay,
     Screen size, Uniformity, Mura, Streaking,Stability, Pixel defects,
     Ringing and handling of under- and over-shoots, Treatment of
     illegal signals, Image sticking (long-term afterimage), Signal
     interfaces, Other facilities



Research & Innovation            46
 The work of EBU P/Display
• Defining the different classes of monitor
  we need
• Deciding what characteristics are important
• Defining the broadcaster’s requirements for
  each class of display




Research & Innovation   47
 The work of EBU P/Display
• Defining the different classes of monitor
  we need
• Deciding what characteristics are important
• Defining the broadcaster’s requirements for
  each class of display
  EBU Tech 3320
  User requirements for Video
  Monitors in Television Production
  www.ebu.ch - Technical Publications


Research & Innovation        48
 The work of EBU P/Display
• Researching and defining methods of
  measuring against these requirements




Research & Innovation   49
 The work of EBU P/Display
• Researching and defining methods of
  measuring against these requirements
• Proposing broadcasters’ requirements for
  consumer displays
  … including, for the first time ever, defining how
   we expect our pictures to look, now we can no
   longer assume a CRT display device




Research & Innovation      50
 The work of EBU P/Display
• Researching and defining methods of
  measuring against these requirements
• Proposing broadcasters’ requirements for
  consumer displays
  … including, for the first time ever, defining how
   we expect our pictures to look, now we can no
   longer assume a CRT display device
      What to do about Overscan


Research & Innovation      51
 The work of EBU P/Display
• Researching and defining methods of
  measuring against these requirements
• Proposing broadcasters’ requirements for
  consumer displays
  … including, for the first time ever, defining how
   we expect our pictures to look, now we can no
   longer assume a CRT display device
      What to do about Overscan
   … adopt SMPTE standardised clean apertures?

Research & Innovation      52
 But I need a new monitor now…

• Professional grade projectors are well worth
  considering
• The best plasma may be better in some
  applications than an LCD
• LCDs should make Grade 1 this year
      (at same cost as a Grade 1 HD CRT)
• But keep an eye out for SED and OLED
• Hang on to your CRTs!
Research & Innovation      53
                    Thank you

             Richard.Salmon@rd.bbc.co.uk



Research & Innovation     54

								
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