[FFmpeg-user] libopenjpeg cinema2k sets wrong GuardBits for SMPTE Bv2.1

Michael Waldowski michael.waldowski at hfu.eu
Fri Feb 2 12:28:48 EET 2024


using ffmpeg with libopenjpeg renders the wrong GuardBits 2 instead of 1, which is
necessary for SMPTE Bv2.1 for cinema2k, see also:
https://github.com/uclouvain/openjpeg/pull/1403

It cannot be set, because the -GuardBits option is missing in ffmpeg for libopenjpeg. 

Code and Messages:

Working (with wrong GuardsBits 2):
$DIR/ffmpeg -i $MOV -vf  $S$P$C -c:v libopenjpeg -format j2k -cinema_mode 2k_48 -profile:v cinema2k -pix_fmt gbrp12 $J2K/%8d.j2c

Not working:
$DIR/ffmpeg -i $MOV -vf  $S$P$C -c:v libopenjpeg -format j2k -cinema_mode 2k_48 -profile:v cinema2k -GuardBits 1 -pix_fmt gbrp12 $J2K/%8d.j2c

Error:
Unrecognized option 'GuardBits'.
Error splitting the argument list: Option not found

Version:
ffmpeg version N-113300-g40bd65a72a-tessus  https://evermeet.cx/ffmpeg/  Copyright (c) 2000-2024 the FFmpeg developers
built with Apple clang version 11.0.0 (clang-1100.0.33.17)

Here you can see the usage of libopenjpeg:
Stream #0:0(eng): Video: jpeg2000, gbrp12le(pc, gbr/bt709/bt709, progressive), 2048x858, q=2-31, 200 kb/s, 25 fps, 25 tbn (default)
    Metadata:
      handler_name    : ?Mainconcept Video Media Handler
      vendor_id       : FFMP
      encoder         : Lavc60.37.100 libopenjpeg

Regards
Mike


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