JVTO026 Invocation of the Inverse MCTF Process

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JVT-O026Invocation of theInverse MCTF Process

• Panasonic Singapore Laboratories
• MenHuang Lee

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Introduction

• MCTF structure not fixed
• Switch dynamically between Haar filter and 5/3
  transform filter
• Multiple reference frames possible
• Inter-partition prediction/update steps removed
  for low delay mode operation
• In SVC WD 1.0, not clear when inverse MCTF is
  invoked
• In JSVM S/W, inverse MCTF invoked at start of
  next GOP

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Problems

• Significant time delay to complete inverse MCTF
  of whole GOP
• Periodic complexity peaks to perform inverse MCTF
  of whole GOP
• Large memory requirement to buffer all pictures
  in a GOP until inverse MCTF process is invoked
• Low delay mode operation not possible

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Proposed Solution

• Define inverse MCTF process such that inverse
  update/prediction steps are distributed across
  all pictures of a partition, as soon as the step
  can be performed
• When to invoke inverse MCTF?
• How to determine when an inverse
  update/prediction steps can be performed?
• What to do during inverse MCTF?

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When to invoke inverse MCTF?

• After all slices of the current picture, pic, is
  decoded from the bitstream
• Bitstream-decoded picture ? decoded from video
  stream but before it undergoes the inverse MCTF
  process

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How to determine when a step can be performed?

• Define, initialize, use update a set of
  variables for each picture, pic

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How to determine when a step can be performed?
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How to determine when a step can be performed?
(curL0, curL1) (1, 0)
(curL0, curL1) (1, 1)
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How to determine when a step can be performed?
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How to determine when a step can be performed?
(0, 1)
(1, 0)
(1, 0)
(1, 1)
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What to do during inverse MCTF?
(1, 0)
(1, 1)
(1, 0)
(2, 0)
(1, 2)
(2, 1)
(1, 0)
(0, 1)
(1, 0)
(1, 1)
(0, 2)
(2, 0)
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What to do during inverse MCTF?
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Illustration
coding order
1
0
2
4
6
5
7
3
temporal level
0
display order
3
prediction
2
update
2
prediction
1
update
1
prediction
0
update
L
0
GOP border
GOP border
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Proposed Modification to SVC WD

• S.8 Decoding process - added description of
  when to invoke inverse MCTF process
• S.8.8 Inverse motion-compensated filtering
  process - replaced
• S.8.8.3 Check for inverse prediction process -
  added
• S.8.8.4 Check for inverse update process - added

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Conclusion

• Inverse update/prediction steps distributed
  across all pictures of a partition, as soon as
  the step can be performed
• Propose when to invoke inverse MCTF
• Propose how to determine when an inverse
  update/prediction steps can be performed, via a
  set of variables
• Propose what to do during inverse MCTF
• Reduce complexity, spreading periodic complexity
  peaks over time
• Reduce time delay, support low delay mode
  operation
• Reduce memory requirement
• No addition of syntax element
• No effect on coding efficiency