Opened 9 years ago

Closed 4 years ago

#1391 closed defect (fixed)

cabac_bypass_alignment_enabled_flag: escapeDataPresent is initialised more often than in specification

Reported by: dominik.wojt Owned by: rajan_joshi
Priority: major Milestone:
Component: SCC text Version: SCM-4.0 (HM-16.4)
Keywords: Cc: rajan_joshi, ksuehring, davidf, karlsharman, jct-vc@…

Description

HM-reference software resets the escapeDataPresent flag more often than it is specified in HEVC v2 specification.

In HEVC v2 specification, "7.3.8.11 Residual coding syntax" escapeDataPresent is being reset once per transform block.

In HM software 16.4
​https://hevc.hhi.fraunhofer.de/svn/svn_HEVCSoftware/tags/HM-16.4/source/Lib/TLibDecoder/TDecSbac.cpp:1395
escapeDataPresentInGroup is being reset every subblock.

This discrepancy can cause bitstream be incorrectly decoded when some subblock other than lastSubBlock has no residuals.

Change History (5)

comment:1 Changed 9 years ago by DefaultCC Plugin

  • Cc ksuehring davidf karlsharman jct-vc@… added

comment:2 Changed 9 years ago by dominik.wojt

This bug is explored by stream
​http://wftp3.itu.int/av-arch/jctvc-site/bitstream_exchange/RExt/EXTPREC_HIGHTHROUGHPUT_444_16_INTRA_10BIT_RExt_Sony_1.zip
making it non conformant to specification.

comment:3 Changed 9 years ago by karlsharman

It appears to me, based on an understanding of the technical intent, that it is the software that is correct and the text that is wrong in this instance. The matter should be discussed at the next JCT-VC meeting (19-26 June 2015).

comment:4 Changed 9 years ago by karlsharman

  • Cc rajan_joshi added
  • Component changed from HM to SCC text
  • Owner set to rajan_joshi
  • Version changed from HM-16.4 to SCM-4.0 (HM-16.4)

This was discussed at the 21st JCT-VC meeting, during the review of the related contribution JCTVC-U0031.

The conclusion was:

Decision: Change the text to match the software.

Ticket is being reassigned to "SCC text".

comment:5 Changed 4 years ago by karlsharman

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

This was corrected in version 4 of the standard.

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  • David Flynn(Subscriber)
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