TANDBERG Television SMPTE presentation (Atlanta) David Mitchinson, Business Development Group

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TANDBERG Television SMPTE presentation(Atlanta)
David Mitchinson,Business Development Group
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The Evolution of DSNG

• Past 10 years has seen a quiet evolution in DSNG
  technology
• Better MPEG-2 encoding
• Better modulator performance with the possibility
  of using DVB-S 8PSK
• Much improved integration and user interfaces
• More features with options for MPEG multiplexing,
  IP data insertion, dual-mode DVB-S / COFDM
  operation
• MPEG-2 HD
• Will the next 2 to 3 years bring about a
  revolution? If so, which technologies will drive
  this?

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DSNG systems Past and present
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The revolution of DSNG?

• Are we going to see a new generation of product
  based upon
• MPEG4-AVC
• What advantages can this deliver?
• Where and when can it be used?
• DVB-S2
• What does it offer compared to DVB-S?
• Are the additional features within the DVB-S2
  standard (VCM and ACM) important?
• This presentation will try and put these new
  technologies into perspective within DSNG and
  CD.
• Lets take a look at MPEG4-AVC first

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MPEG4-AVC.What is it?

• MPEG-4 is designed to build upon the success of
  MPEG-2 to provide better pictures at lower
  bitrates.
• Much of the basic MPEG-2 encoding philosophy has
  been carried over. Some tools have been replaced
  and many new tools have been added.
• MPEG-4 by itself is misleading you must be
  specific since it appears in 2 commonly used but
  very different profiles
• - Baseline (Designed to be simple to implement
  on devices with simple encoders and lower
  resolution displays)
• Video conferencing, Mobile phones, IPOD devices,
  PDAs
• Main (designed for broadcast applications but
  needs a more powerful encoder). Primary goal was
  to out-perform MPEG-2 for broadcast
• Broadcasting

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Applications ? Video Profiles/Levels
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Comparison of tools (1 of 3)
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Comparison of tools (2 of 3)
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Comparison of tools (3 of 3)
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MPEG4-AVC.What is it?
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MPEG4-AVC.What can it do?

• Forget baseline profile its not intended for
  broadcast. It can be used, but offers no
  advantage over MPEG-2
• Main profile is what is needed for Broadcast
  applications. It is commonly known as H.264,
  MPEG-4 AVC Main or High profile and MPEG-4 part
  10.
• Main profile was developed to provide better
  compression than MPEG-2 for DTH and is delivering
  encoding efficiency gains of up to 50 to 60
  compared with MPEG-2. However, this is bitrate
  and content dependent!
• The high efficiency of MPEG-4 can allow video of
  satisfactory quality to be delivered below the
  bitrates that MPEG-2 achieves

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Improvements in encoding efficiency
MPEG-2 Video
Bit rate for Broadcast Quality HDTV
Bit Rate (Mbps)
Time
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MPEG-4 AVC performance V MPEG-2
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MPEG-4 AVC performance V MPEG-2
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MPEG-4 AVC performance V MPEG-2
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But this is for DTH how about CD?

• There are very significant differences between
  DTH and CD applications. Mobile DSNG is an
  example of CD.
• DTH bitrates are comparatively low, enabling
  MPEG4-AVC to achieve greatest efficiency and
  advantage over MPEG-2. They are higher for CD to
  keep the quality up.
• DTH applications do not normally worry about
  encoder / decoder latency. This is critically
  important for encoder performance. CD does care
  about latency.
• For DTH, the quality expectation can be much
  lower than for CD and transmissions are always
  420. CD can be either 420 or 422.
• MPEG-4 is so good for DTH that Virtually all DTH
  providers are using it for new direct to home HD
  services. Most are coupling the encoding benefits
  with the efficiency savings offered by DVB-S2
  modulation. But how about MPEG-4 in professional
  CD (DSNG?)

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AVC for CD What is available today?
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MPEG-4 and Latency

• Latency is of fundamental importance to the
  design of the encoder.
• Most good MPEG-2 encoders (HD or SD) can achieve
  approx. 0.5s end to end latency in standard mode,
  using I, P and B frames
• Achieving less than 0.5s means that tools
  increasingly have to be removed. B-frames cannot
  be used if very low latency is required.
• Most CD applications can therefore use MPEG-2
  with B frames and meet latency requirements

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MPEG-4 and Latency

• Current MPEG-4 systems typically achieve approx 3
  to 4 seconds end to end latency when using the
  full toolset
• This is far to high for most CD applications,
  and MPEG-4 has often been excluded because of
  this.
• Surprisingly though, it is the DTH focus of the
  encoders and the fact that delay has not so-far
  been considered important that is responsible. It
  is not MPEG-4 that is necessarily responsible for
  high latency.
• Currently, manufacturers are starting to focus
  upon latency-conscious applications for MPEG-4

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MPEG-4 and Latency

• Achieving 0.5s end to end delay with MPEG-4 is
  now possible
• Universally, todays encoders achieve low latency
  using more compromises than are necessary. B
  frames are usually dropped earlier than they
  could be, reducing performance compared with
  MPEG-2.
• In other words, its still early days for the
  optimisation of MPEG-4 encoders towards
  latency-critical applications. The performance
  will get better!
• In many cases, software updates should deliver
  increasing performance using the same hardware
• If you can afford approx. 0.5s latency, then the
  performance improvements could be very
  significant. Below 0.5s, the performance may not
  improve significantly.

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Effects of low-latency on MPEG4-AVC
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So, where does MPEG4-AVC fit with professional
CD?

• Now that we know what MPEG4-AVC offers today, and
  could offer tomorrow, we can see more clearly
  where it could fit.
• CD covers a huge spectrum of applications.
• Some of these require greater video quality than
  others most CD applications are delay critical.
• To understand these applications, you must break
  the CD market down into smaller sub-segments.
  This has been done as follows

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CD (DSNG) A diverse market

• Four Sub-Segments of CD
• SD Newsgathering
• SD high-quality contribution / events
• HD Newsgathering
• HD high-quality contribution / events
• Requirements for each are very different!
• The following table highlights the differences.

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Four sub-segments of CD (DSNG)
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Relative size of each sub-segment
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Can MPEG4-AVC help with SD newsgathering?

• In most cases, MPEG-2 is good enough to provide
  economical transmission
• The MPEG-2 bitrate is normally too high to
  provide much advantage with MPEG-4.
• There is consequently little interest in
  MPEG4-AVC for SD Newsgathering DSNG applications
  the capital investment in replacing equipment is
  simply too high
• There is interest in using MPEG4-AVC for new,
  non-satellite applications. For example,
  MPEG4-AVC can make low-bitrate links (typically
  sub 1.5Mb/s, such as E1, DSL etc.) suitable for
  delivering newsgathering video.

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Can MPEG4-AVC help with SD Events Coverage?

• Since 422 is normally required, only MPEG-2 can
  currently provide this and so only MPEG-2 will
  do.
• In the future, MPEG4-AVC may be applicable but
  equipment supporting 422 profile (Hi422P) will
  have to be made available first. This will start
  to appear in 2008.
• Over the longer term (during next 5 years), a
  very high proportion of SD contribution will
  migrate to HD making high-quality SD contribution
  much less commonplace.

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Can MPEG4-AVC help with HD Newsgathering?

• HD newsgathering is cost-conscious Newsgathering
  is the last activity to go HD.
• HD Newsgathering is nearly always 420
• It is also often delay conscious which can
  currently limit the compression efficiency and
  relative difference between AVC and MPEG-2. The
  benefits of AVC will improve however.
• Achieving the lowest bitrate possible is an
  essential requirement to
• Keep satellite transponder bandwidths low
• Ensure an easy migration path for trucks without
  having to replace expensive parts such as dish
  and HPA
• Can also be used for DENG (COFDM / terrestrial
  microwave) applications to improve range and
  robustness

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Can MPEG4-AVC help with HD Events Coverage?

• In the future, AVC will replace MPEG-2 for
  high-quality HD contribution, but the high
  bitrate will make the performance gain fairly low
• Currently, the lack of equipment supporting the
  422 profile is a big issue
• Equipment supporting 422 solutions will start
  to become available during 2008

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Enough of encoding!

• Lets now look at new satellite modulation
  technology
• Nothing to do with the encoder!
• Can be used with any type of encoder (MPEG-2,
  MPEG-4 etc.) since encoder independent
• Aim is to combine the benefits of best encoding
  and most efficient modulation to provide best
  performance.

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DVB-S2 A new MODULATION technology

• DVB-S2 purely affects the modulator and the
  transmission of data to the satellite
• DVB-S2 is simply more efficient than DVB-S (which
  it replaces). So, for the same bandwidth DVB-S2
  can either transmit more data, or the same data
  rate with more robustness, or a bit of both.
• You need to have a DVB-S2 demodulator in your
  receiver. Make sure it supports all of the DVB-S2
  features you wish to use!

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DVB-S2 The easy way to save 35 bandwidth
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ExampleMPEG-4 AVC and DVB-S2
26 bit-rate gain with same link margin
Assumes stat muxing used
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Why is DVB-S2 better?

• Fundamental benefits come from new, more powerful
  error correction
• Since 1994, Silicon density has increased by
  approximately 16 times (Moores law)
• Forward Error Correction has been transformed by
  iterative decoding
• DVB-S2 uses Low Density Parity Check coding,
  Invented in 1960 by Gallagher!
• 40 year wait for cost effective Silicon
  implementation
• Performance Only 0.7dB to 1dB from the Shannon
  limit. Its so good, No redesign in our
  lifetime ??
• New modulation schemes also offer better
  performance
• Please see document TANDBERG guide to DVB-S2
  for further information

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DVB-S2 do you know the whole story?

• There are other sub-standards of DVB-S2 that are
  not currently well known but could become very
  important
• VCM allows the modulator to change the modulation
  scheme and FEC seamlessly
• ACM is an extension to VCM. If you have a
  receiver that can report its reception conditions
  back to the modulator, you can always operate at
  maximum data rate!
• No longer necessary to operate with fade margins
  you may not need!

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DVB-S2, VCM and ACM
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DVB-S2 ACM
C-Band 25
KU-Band 55
KA-Band 100
Eb/No
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Potential benefits of ACM
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Final Conclusions!

• MPEG4-AVC expected to replace MPEG-2 for CD as
  the low-latency performance improves and 422
  profiles are implemented
• Many already realising the benefits of basic
  DVB-S2, but there are other very useful but less
  well known tools within the DVB-S2 standard
• Implementing these will provide even greater
  savings
• Combining MPEG4-AVC and DVB-S2, with ACM where
  practicable, will be the way to go!
• The combined efficiency benefits could be
  revolutionary for HD

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TANDBERG Television SMPTE presentationDavid
Mitchinson,Buisness Development Group