Opened 8 years ago

Closed 8 years ago

#1058 closed defect (fixed)

Minor issue with the definition of offsetSign in the SAO semantics section (7.4.9.3)

Reported by: alexis Owned by:
Priority: minor Milestone: D10
Component: Text Version:
Keywords: Cc: bbross, wjhan, jct-vc@…

Description

In the current specification (JCTVC-L1003_v34) in section 7.4.9.3, in the semantics of sao_offset_sign, a temporary variable, named offsetSign is defined that specifies the sign for each SAO class.

Given the relationship of offsetSign with class index i, and of offsetSign later being used in equation 7-58 where offsetSign should vary within the for loop according to the value of i, it seems more appropriate to maybe, instead of defining a single variable, to define offsetSign as an array. As it is, it seems that maybe equation 7.58 could be misinterpreted.

Maybe also an alternative, instead of using offsetSign could be to use an equation of the form:

============
SaoOffsetVal[ cIdx ][ rx ][ ry ][ 0 ] = 0
for( i = 0; i < 4; i++ )
SaoOffsetVal[ cIdx ][ rx ][ ry ][ i + 1 ] =

(1 - 2 * sao_offset_sign[ cIdx ][ rx ][ ry ][ i ] ) * sao_offset_abs[ cIdx ][ rx ][ ry ][ i ] << ( bitDepth − Min( bitDepth, 10 ) )

============

and alter the semantics of sao_offset_sign so as it is appropriate initialized/set for all SAO categories, i.e.:

==============

If SaoTypeIdx[ cIdx ][ rx ][ ry ] then,

sao_offset_sign[ cIdx ][ rx ][ ry ][ 0 ] = sao_offset_sign[ cIdx ][ rx ][ ry ][ 1 ] = 0
sao_offset_sign[ cIdx ][ rx ][ ry ][ 1 ] = sao_offset_sign[ cIdx ][ rx ][ ry ][ 3 ] = 1

otherwise

– If sao_merge_left_flag is equal to 1, sao_offset_sign[ cIdx ][ rx ][ ry ][ i ] is inferred to be equal to sao_offset_sign[ cIdx ][ rx − 1 ][ ry ][ i ].

– Otherwise, if sao_merge_up_flag is equal to 1, sao_offset_sign[ cIdx ][ rx ][ ry ][ i ] is inferred to be equal to sao_offset_sign[ cIdx ][ rx ][ ry − 1 ][ i ].

– Otherwise, sao_offset_sign[ cIdx ][ rx ][ ry ][ i ] is inferred to be equal 0.

===============

Kind regards,

Alexis

Change History (2)

comment:1 Changed 8 years ago by DefaultCC Plugin

  • Cc bbross wjhan jct-vc@… added

comment:2 Changed 8 years ago by bbross

  • Resolution set to fixed
  • Status changed from new to closed

Fixed in version 1

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  • Alexis Tourapis(Reporter)
  • Benjamin Bross(Subscriber, Participant)
  • jct-vc@…(Subscriber)
  • karl.sharman@…(Always)
  • Karsten Suehring(Always)
  • Woo-Jin Han(Subscriber)