[FFmpeg-trac] #4653(avcodec:open): jpeg2000: -M 1 mode is not lossless (compared to openjpeg)

[FFmpeg]

#4653: jpeg2000: -M 1 mode is not lossless (compared to openjpeg)
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             Reporter:  ami_stuff   |                    Owner:
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:  j2k         |               Blocked By:
             Blocking:              |  Reproduced by developer:  1
Analyzed by developer:  0           |
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Comment (by boxerab):

 I have been looking into this very problem on the OpenJPEG side of things.

 This is a bug in OpenJPEG - lossless encoding with M==1 (i.e. BYPASS mode)
 or M ==4 (RESTART mode) gives a lossy image.

 This has been broken for years and years.

 I have opened an issue on OpenJPEG github tracker:

 https://github.com/uclouvain/openjpeg/issues/674

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Ticket URL: <https://trac.ffmpeg.org/ticket/4653#comment:6>
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