I am annotating a set of about 40 exams. Around exam number 17 I get these messages:

OpenCV(3.4.1) Error: Unknown error code -10 (Raw image encoder error: Empty JPEG image (DNL not supported)) in throwOnEror, file /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_graphics_opencv/opencv/work/opencv-3.4.1/modules/imgcodecs/src/grfmt_base.cpp, line 145
libc++abi.dylib: terminating with uncaught exception of type cv::Exception: OpenCV(3.4.1) /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_graphics_opencv/opencv/work/opencv-3.4.1/modules/imgcodecs/src/grfmt_base.cpp:145: error: (-10) Raw image encoder error: Empty JPEG image (DNL not supported) in function throwOnEror

Warning: unable to close filehandle GEN7 properly: Broken pipe at /opt/local/lib/perl5/vendor_perl/5.26/AMC/Subprocess.pm line 105, <GEN8> line 7133.

After that the annotation process stops without generating the rest.

When I saw "Empty JPEG image" I wondered if it was due to missing pages. I do have missing pages, but they are on exams with different numbers (27 and 38). Any ideas?