Opened 9 years ago

Closed 9 years ago

#669 closed defect (duplicate)

HM-8.0: Enabling dependent slices causes encoder/decoder mismatch.

Reported by: pieterkapsenberg Owned by:
Priority: minor Milestone: HM-8.1
Component: HM Version: HM-8.0
Keywords: Cc: fbossen, ksuehring, davidf, jct-vc@…


(No entry for HM-8.0 in the tracker)

Encoding a sequence with the following added to the cfg:

DependentSliceMode : 2
DependentSliceArgument : 15000
CabacIndependentFlag : 0

causes digest mismatches when running the decoder.

Attachments (2)

depslices.cfg (7.8 KB) - added by pieterkapsenberg 9 years ago.
RaceHorses_lowdelay_dep_slices.bin (25.2 KB) - added by pieterkapsenberg 9 years ago.

Download all attachments as: .zip

Change History (11)

comment:1 Changed 9 years ago by DefaultCC Plugin

  • Cc fbossen ksuehring davidf jct-vc@… added

comment:2 Changed 9 years ago by ksuehring

  • Version changed from HM-7.1 to HM-8.0

comment:3 Changed 9 years ago by pieterkapsenberg

In particular, the RaceHorses stream looks too "green", the later slices have an odd green tint, suggesting maybe a qP issue propagating between the dependent slices.

comment:4 Changed 9 years ago by pieterkapsenberg

Also, the slice header syntax regarding the dependent_slice flag does not match the Text.

comment:5 Changed 9 years ago by ksuehring

High level syntax changes are usually applied in the x.1 versions, so we are probably on track with that. Actually I'm not sure if I have already seen anybody volunteering for implementing that ad-hoc change, but we can take care of it.

Regarding the mismatch we had problems reproducing it. Can you please share the complete configuration you used?

Changed 9 years ago by pieterkapsenberg

Changed 9 years ago by pieterkapsenberg

comment:6 Changed 9 years ago by pieterkapsenberg

stream and cfg attached, ran with this command line:

./bin/TAppEncoderStatic --SEIpictureDigest -c depslices.cfg -fr 30 -i ../yuv/RaceHorses_832x480_30.yuv -f 1 -wdt 832 -hgt 480 -b RaceHorses_lowdelay_dep_slices.bin

comment:7 Changed 9 years ago by adarsh

There is another minor inconsistency with the implementation of dependent slices. The dependent slice is signalled by dependent_slice_flag, and dependent_slices_enabled_flag only signals whether dependent_slice_flag is present in the slice header or not. In most places in the the software (HM8.0), the variable for dependent_slices_enabled_flag, which is m_bDependentSlicesEnabledFlag, is used to check if the slice is a dependent slice.

comment:8 Changed 9 years ago by ksuehring

It seem the issue is not directly related to dependent slices. The configuration file uses:

DeltaQpRD: 1

which also causes mismatches for "regular" slices. I have tested using SliceMode:1 and 2, the mismatch happens for both.

comment:9 Changed 9 years ago by ksuehring

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

Closed as duplicate of #671.
I'll mark this a as duplicate for 671 which has the description of the actual cause of the mismatch.

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  • Adarsh Krishnan Ramasubramonian(Participant)
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  • Frank Bossen(Subscriber)
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  • Karsten Suehring(Subscriber, Participant, Always)
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