The subtitles are burned in.

https://archive.org/download/1937lagrandeillusion/1937%20la_grande_illusion_1937___5a8f7ca95fab1.mp4 - 409.9M, 'source="original"'

>ffprobe -i "1937 la_grande_illusion_1937___5a8f7ca95fab1.mp4"
ffprobe version git-2020-06-20-29ea4e1 Copyright (c) 2007-2020 the FFmpeg developers
built with gcc 9.3.1 (GCC) 20200523
configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libgsm --disable-w32threads --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
libavutil 56. 55.100 / 56. 55.100
libavcodec 58. 93.100 / 58. 93.100
libavformat 58. 47.100 / 58. 47.100
libavdevice 58. 11.100 / 58. 11.100
libavfilter 7. 86.100 / 7. 86.100
libswscale 5. 8.100 / 5. 8.100
libswresample 3. 8.100 / 3. 8.100
libpostproc 55. 8.100 / 55. 8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'C:\Users\1937 la_grande_illusion_1937___5a8f7ca95fab1.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
title : La grande illusion 1937 - Studio Canal Blu-ray
encoder : Lavf58.3.100
Duration: 01:53:42.33, start: 0.000000, bitrate: 503 kb/s
Chapter #0:0: start 0.000000, end 489.958000
Metadata:
title : 00:00:00.000
Chapter #0:1: start 489.958000, end 1052.167000
Metadata:
title : 00:08:09.917
Chapter #0:2: start 1052.167000, end 1788.333000
Metadata:
title : 00:17:32.167
Chapter #0:3: start 1788.333000, end 2106.125000
Metadata:
title : 00:29:48.333
Chapter #0:4: start 2106.125000, end 2698.625000
Metadata:
title : 00:35:06.125
Chapter #0:5: start 2698.625000, end 3438.000000
Metadata:
title : 00:44:58.625
Chapter #0:6: start 3438.000000, end 3790.958000
Metadata:
title : 00:57:18.000
Chapter #0:7: start 3790.958000, end 4366.542000
Metadata:
title : 01:03:10.958
Chapter #0:8: start 4366.542000, end 5343.875000
Metadata:
title : 01:12:46.500
Chapter #0:9: start 5343.875000, end 5937.833000
Metadata:
title : 01:29:03.875
Chapter #0:10: start 5937.833000, end 6421.792000
Metadata:
title : 01:38:57.833
Chapter #0:11: start 6421.792000, end 6822.333000
Metadata:
title : 01:47:01.667
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 496x360 [SAR 495:496 DAR 11:8], 383 kb/s, 24 fps, 24 tbr, 12288 tbn, 48 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(fra): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 117 kb/s (default)
Metadata:
handler_name : SoundHandler
Stream #0:2(und): Data: bin_data (text / 0x74786574)
Metadata:
handler_name : SubtitleHandler
Unsupported codec with id 100359 for input stream 2