Opened 9 years ago

Closed 7 years ago

Last modified 7 years ago

#530 closed defect (fixed)

Encoder/decoder mismatch when chroma QP offsets are used

Reported by: tkunlin Owned by:
Priority: minor Milestone: HM-16.1
Component: HM Version: HM-7.0
Keywords: Cc: fbossen, ksuehring, davidf, jct-vc@…, skanumu@…


It occurs on the 5th picture of the stream generated with the following command line :

bin/TAppEncoderStatic -c cfg/encoder_lowdelay_P_main.cfg -c cfg/per-sequence/BasketballPass.cfg -f 8 -q 37 --ChromaQpOffset=-4 --ChromaQpOffset2nd=4

Change History (5)

comment:1 Changed 9 years ago by DefaultCC Plugin

  • Cc fbossen ksuehring davidf jct-vc@… added

comment:2 Changed 9 years ago by sandeepkanumuri

  • Cc skanumu@… added
  • Version changed from HM-6.2 to HM-7.0

Updating the defect to HM-7.0 from HM-6.2 since it is still present in this version, but the behavior might be different. Also, the command line parameters might need to be modified as well.

In HM-7.0, I got an encoder-decoder mismatch starting from the 2nd frame (first I-frame matched correctly) whenever I used different QP offsets for Cb and Cr.
1) TAppEncoder.exe -c encoder_randomaccess_main.cfg -c RaceHorses.cfg --FramesToBeEncoded=9 --QP=32 --CbQpOffset=4 --CrQpOffset=5
2) TAppEncoder.exe -c encoder_randomaccess_main.cfg -c RaceHorses.cfg --FramesToBeEncoded=9 --QP=32 --CbQpOffset=2 --CrQpOffset=4

I used same offsets for a couple of config settings and I was not able to replicate the encoder-decoder mismatch.
1) TAppEncoder.exe -c encoder_lowdelay_P_main.cfg -c BasketballPass.cfg --FramesToBeEncoded=8 --QP=37 --CbQpOffset=4 --CrQpOffset=4
2) TAppEncoder.exe -c encoder_randomaccess_main.cfg -c RaceHorses.cfg --FramesToBeEncoded=9 --QP=32 --CbQpOffset=2 --CrQpOffset=2

I was also not able to replicate the encoder-decoder mismatch when I did all intra coding on a couple of sequences.
1) TAppEncoder.exe -c encoder_intra_main.cfg -c RaceHorses.cfg --FramesToBeEncoded=9 --QP=32 --CbQpOffset=4 --CrQpOffset=5
2) TAppEncoder.exe -c encoder_intra_he10.cfg -c BasketballPass.cfg --FramesToBeEncoded=8 --QP=37 --CbQpOffset=2 --CrQpOffset=4

comment:3 Changed 9 years ago by sandeepkanumuri

I found a case with encoder-decoder mismatch when both cb and cr offsets are the same:
TAppEncoder.exe -c encoder_randomaccess_main.cfg -c RaceHorses.cfg --FramesToBeEncoded=9 --QP=22 --CbQpOffset=12 --CrQpOffset=12

comment:4 Changed 7 years ago by karlsharman

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

These cases do not cause a problem with the latest software.
Chroma offsets have been studied and fixed during RExt development, which has now been merged into HM.

comment:5 Changed 7 years ago by ksuehring

  • Milestone set to HM-16.1
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