Opened 2 years ago

Last modified 4 months ago

#4365 new defect

Multithreaded slice decoding in HEVC producing incorrect output

Reported by: kurosu Owned by:
Priority: important Component: avcodec
Version: git-master Keywords: HEVC regression
Cc: jsantiago@fastmail.us Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no

Description

When using the appropriate sequence (containing slices or wavefronts), that kind of command-line produce varying CRCs:
./ffmpeg -threads 12 -thread_type slice -i <seq> -an -sn -f crc -

The expected output is a constant CRC, indicating valid decoding. This is what happends when 1 thread is used, or thread type is frame.

This is a regression since cf92cc8. The commit in itself can cause crashes, and to test it, 7117547 is required. I'm unfortunately not sure if any other commit/fix is required. Note that the code has changed much since cf92cc8, but the issue is still present.

The sequence on which I observed it is unfortunately not distribuable, and I don't know what freely distribuable sequence would exhibit the issue.

Change History (6)

comment:1 Changed 2 years ago by kurosu

  • Cc christophe.gisquet@gmail.com added
  • Version changed from unspecified to git-master

comment:2 Changed 23 months ago by cehoyos

  • Keywords regression added
  • Priority changed from normal to important

Please provide an input sample that allows to reproduce this issue.

comment:3 Changed 20 months ago by cehoyos

Is this problem still reproducible? Ronald fixed a bug that may be related.

comment:4 Changed 12 months ago by jlsantiago0

  • Cc jsantiago@fastmail.us added

comment:5 Changed 4 months ago by kurosu

  • Cc christophe.gisquet@gmail.com removed

comment:6 Changed 4 months ago by cehoyos

Would you mind telling us if the issue is still reproducible?

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