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Static Macroblocks.070307.ppt
 

Static Macroblocks.070307.ppt

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  • Based on information sent from Tandberg’s 6000 and Edge systems (using a 3 rd party networking tool), they can only accept up to 35,000 and 25,000 macroblocks and maintain 30fps in a dynamic environment. Using standard calculations, that means that the maximum resolution TAA can output with the MXP is 448p and still maintain 30fps. And on the Edge, it’s lower at 400p.

Static Macroblocks.070307.ppt Static Macroblocks.070307.ppt Presentation Transcript

  • Understanding Macroblocks
  • What is a Macroblock?
    • The basic building block of a video image
    • A macroblock is 256 square pixels
      • 16 vertical by…
      • 16 horizontal
    • Video conferencing images are made from dynamic macroblocks
    • 720p HD is defined as:
      • 1280 horizontal pixels
      • 720 vertical pixels
    • Video conferencing should support 30fps for business quality motion handling
    16 pixels 16 pixels Macroblock
  • Dynamic Macroblocks Needed for 720p, 30fps?
    • How many dynamic macroblocks per second does an HD video conferencing system need to en co de and dec ode?
    1280h x 720v = 921,600 pixels per frame 921,600 ÷ 16h ÷ 16v = 3,600 macroblocks per frame 3,600 x 30 = 108,000 macroblocks per second 108,000 macroblocks/second
  • What Does TANDBERG Provide?
    • TANDBERG cannot co de and dec ode full HD video due to limited dynamic macroblock (video building blocks) capability
    400p 720p HD Standard Non-Standard 448p
    • Limited macroblock capability forced TANDBERG to non-standard (lower resolution, non-HD) formats where they could dynamically co de and dec ode at 30fps
    Fully Dynamic Video at 30fps Maximum Dynamic Macroblocks
  • Video Formats and Dynamic Macroblock Requirements
  • Static Macroblocks
    • Static Macroblock technology was developed by Polycom
    • This technology was designed to improve frame rates for content sharing, where images had small changes
    • Reducing the dynamic macroblocks reduces the workload placed on the codec.
      • If you are struggling to achieve higher frame rates, this is one way to push up that number.
    • However, this comes at a price. When you rely on static macroblocks and real motion takes place, the video quality suffers with video blurring, blocking and unnatural motion caused by drops in frame rate
  • TANDBERG and Static Macroblocks
    • Makes their frame rate statistics look higher when there is very little motion
    • Environments with motion suffer as frame rates drop:
      • People moving in the video image
      • Camera movements (panning, tilting, zooming)
      • Switching to alternate video sources (DVD, VCR, 2 nd camera)
    • TANDBERG systems will not negotiate with other vendors that support full dynamic macroblocks
      • Why? Codec is underpowered to deliver true HD (108,000 macroblocks per second) and can not fully co de and dec ode
      • Will force real, dynamic HD systems to drop down to 4CIF or lower where they can handle dynamic decode
  • Summary
    • High definition video conferencing is a very specific science and well-defined
    • TANDBERG does not meet this definition
    • In order to compensate for not delivering true, dynamic HD, TANDBERG uses Static Macroblocks to reduce workload on its video conferencing codecs and claim higher frame rates
    • Polycom HDX 9000 solutions deliver true HD at 30fps, even in highly dynamic environments