/usr/include/mjpegtools/mpeg2enc/ is in libmjpegtools-dev 1:2.1.0+debian-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/mjpegtools/mpeg2enc/elemstrmwriter.hh
/usr/include/mjpegtools/mpeg2enc/encoderparams.hh
/usr/include/mjpegtools/mpeg2enc/encodertypes.h
/usr/include/mjpegtools/mpeg2enc/imageplanes.hh
/usr/include/mjpegtools/mpeg2enc/macroblock.hh
/usr/include/mjpegtools/mpeg2enc/mpeg2coder.hh
/usr/include/mjpegtools/mpeg2enc/mpeg2encoder.hh
/usr/include/mjpegtools/mpeg2enc/mpeg2encoptions.hh
/usr/include/mjpegtools/mpeg2enc/mpeg2encparams.h
/usr/include/mjpegtools/mpeg2enc/mpeg2syntaxcodes.h
/usr/include/mjpegtools/mpeg2enc/ontheflyratectlpass1.hh
/usr/include/mjpegtools/mpeg2enc/ontheflyratectlpass2.hh
/usr/include/mjpegtools/mpeg2enc/picture.hh
/usr/include/mjpegtools/mpeg2enc/picturereader.hh
/usr/include/mjpegtools/mpeg2enc/predict_ref.h
/usr/include/mjpegtools/mpeg2enc/quantize.hh
/usr/include/mjpegtools/mpeg2enc/quantize_ref.h
/usr/include/mjpegtools/mpeg2enc/ratectl.hh
/usr/include/mjpegtools/mpeg2enc/seqencoder.hh
/usr/include/mjpegtools/mpeg2enc/streamstate.h
/usr/include/mjpegtools/mpeg2enc/synchrolib.h
/usr/include/mjpegtools/mpeg2enc/syntaxconsts.h