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IDProjectCategoryView StatusLast Update
0000015JVT JM H.264/AVC reference softwaredecoderpublic2008-07-24 16:37
ReporterRamandeep Sandhu Assigned ToAlexis Michael Tourapis  
PrioritynormalSeverityminorReproducibilityalways
Status resolvedResolutionfixed 
Product VersionJM 10.2 
Fixed in VersionJM-14.1 
Summary0000015: Chroma transform coefficient decoding process for SP/SI
DescriptionIn the Chroma transform coefficient decoding process for SP/SI , eqn 8-449 as specified in the H.264 Specification(03/05) right shifts a signed quantity.Where as in the Implementation of this eqn in the JM10.2, first the unsigned quantity is being right shifted and then being multiplied with the sign.It is to be understood that both these steps would produce different results.It is still unclear whether this is a typo error in the specification or wrong implementation in the reference software.
dc(ij)s = ( Sign( dc(ij)p ) * ( Abs( dc(ij)p ) * LevelScale2( QSC % 6, 0, 0 ) +
             ( 1 << ( 15 + QSC / 6 ) ) ) ) >> ( 16 + QSC / 6 ) with i, j = 0, 1
                                                                - ( 8-449)
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Activities

Alexis Michael Tourapis

2008-07-24 16:37

developer   ~0000212

Fixed

Issue History

Date Modified Username Field Change
2006-09-20 12:55 Ramandeep Sandhu New Issue
2008-07-24 16:37 Alexis Michael Tourapis Note Added: 0000212
2008-07-24 16:37 Alexis Michael Tourapis Status new => resolved
2008-07-24 16:37 Alexis Michael Tourapis Fixed in Version => JM-14.1
2008-07-24 16:37 Alexis Michael Tourapis Resolution open => fixed
2008-07-24 16:37 Alexis Michael Tourapis Assigned To => Alexis Michael Tourapis