Opened 9 years ago

Closed 7 years ago

#490 closed defect (fixed)

Redundant RBSP trailing bits at the end of slice

Reported by: sandeepkanumuri Owned by:
Priority: minor Milestone:
Component: HM Version: HM-6.1
Keywords: Cc: fbossen, ksuehring, davidf, jct-vc@…

Description

In HM-6.1, all substreams are byte-aligned by inserting RBSP trailing bits at the end. However, there is another call to insert RBSP trailing bits after all substreams are added to the main stream. The final addition of RBSP trailing bits in redundant and unnecessary. According to the specification, there should be only one instance of RBSP trailing bits insertion at the end of a tile/wavefront if that also happens to be the end of the slice as well.

I think the mitigation can be simply achieved by commenting/removing the following statement at line 1186 in compressGOP() function.
writeRBSPTrailingBits(nalu.m_Bitstream);

Change History (4)

comment:1 Changed 9 years ago by DefaultCC Plugin

  • Cc fbossen ksuehring davidf jct-vc@… added

comment:2 Changed 9 years ago by ksuehring

Actually the substream termination should use writeRBSPTrailingBits() to write the trailing bits.

It also seems as if there is after

            pcSubstreamsOut[ui].write( 1, 1 ); // stop bit.
#if TILES_WPP_ENTRY_POINT_SIGNALLING
            pcSubstreamsOut[ui].writeAlignZero();
#endif

another mechanism that tests byte alignment which should not be necessary, also later another alignment for entropy slices happens. Looks quite unclear what is happening there when. Please provide a cleanup patch.

comment:3 Changed 9 years ago by ksuehring

The suggested fix has been checked in into HM-6.1 in r2215. Further cleanup is required.

comment:4 Changed 7 years ago by fbossen

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