I think I got the pertinent data here ... I cleared all the logs and started one of the files that's having the issue ..
ffmpeg version 5.1.3-Jellyfin Copyright © 2000-2022 the FFmpeg developers
built with gcc 12-win32 (GCC)
configuration: --prefix=/opt/ffmpeg --arch=x86_64 --target-os=mingw32 --cross-prefix=x86_64-w64-mingw32- --pkg-config=pkg-config --pkg-config-flags=--static --extra-libs='-lfftw3f -lstdc++' --extra-cflags=-DCHROMAPRINT_NODLL --extra-version=Jellyfin --disable-ffplay --disable-debug --disable-doc --disable-sdl2 --disable-ptx-compression --disable-w32threads --enable-pthreads --enable-shared --enable-lto --enable-gpl --enable-version3 --enable-schannel --enable-iconv --enable-libxml2 --enable-zlib --enable-lzma --enable-gmp --enable-chromaprint --enable-libfreetype --enable-libfribidi --enable-libfontconfig --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libopenmpt --enable-libwebp --enable-libvpx --enable-libzimg --enable-libx264 --enable-libx265 --enable-libsvtav1 --enable-libdav1d --enable-libfdk-aac --enable-opencl --enable-dxva2 --enable-d3d11va --enable-amf --enable-libmfx --enable-ffnvcodec --enable-cuda --enable-cuda-llvm --enable-cuvid --enable-nvdec --enable-nvenc
libavutil 57. 28.100 / 57. 28.100
libavcodec 59. 37.100 / 59. 37.100
libavformat 59. 27.100 / 59. 27.100
libavdevice 59. 7.100 / 59. 7.100
libavfilter 8. 44.100 / 8. 44.100
libswscale 6. 7.100 / 6. 7.100
libswresample 4. 7.100 / 4. 7.100
libpostproc 56. 6.100 / 56. 6.100
Input #0, matroska,webm, from 'file:H:\Anime Movies\<redacted>.mkv':
Metadata:
CREATION_TIME : 2019-06-15T08:06:07Z
ENCODER : Lavf57.7.2
Duration: 01:48:54.82, start: 0.000000, bitrate: 2709 kb/s
Chapters:
Chapter #0:0: start 0.000000, end 328.537000
Metadata:
title : 00:00:00.000
Chapter #0:1: start 328.537000, end 419.044000
Metadata:
title : 00:05:28.537
Chapter #0:2: start 419.044000, end 916.874000
Metadata:
title : 00:06:59.044
Chapter #0:3: start 916.874000, end 1309.433000
Metadata:
title : 00:15:16.749
Chapter #0:4: start 1309.433000, end 1399.023000
Metadata:
title : 00:21:49.391
Chapter #0:5: start 1399.023000, end 1508.924000
Metadata:
title : 00:23:19.023
Chapter #0:6: start 1508.924000, end 1767.099000
Metadata:
title : 00:25:08.924
Chapter #0:7: start 1767.099000, end 1975.474000
Metadata:
title : 00:29:27.099
Chapter #0:8: start 1975.474000, end 2301.466000
Metadata:
title : 00:32:55.473
Chapter #0:9: start 2301.466000, end 2498.246000
Metadata:
title : 00:38:21.466
Chapter #0:10: start 2498.246000, end 2622.036000
Metadata:
title : 00:41:38.246
Chapter #0:11: start 2622.036000, end 2925.172000
Metadata:
title : 00:43:42.036
Chapter #0:12: start 2925.172000, end 3183.472000
Metadata:
title : 00:48:45.172
Chapter #0:13: start 3183.472000, end 3467.172000
Metadata:
title : 00:53:03.472
Chapter #0:14: start 3467.172000, end 3684.472000
Metadata:
title : 00:57:47.172
Chapter #0:15: start 3684.472000, end 3885.840000
Metadata:
title : 01:01:24.472
Chapter #0:16: start 3885.840000, end 4063.059000
Metadata:
title : 01:04:45.840
Chapter #0:17: start 4063.059000, end 4275.605000
Metadata:
title : 01:07:43.059
Chapter #0:18: start 4275.605000, end 4434.263000
Metadata:
title : 01:11:15.605
Chapter #0:19: start 4434.263000, end 4709.205000
Metadata:
title : 01:13:54.263
Chapter #0:20: start 4709.205000, end 4900.020000
Metadata:
title : 01:18:29.204
Chapter #0:21: start 4900.020000, end 5081.201000
Metadata:
title : 01:21:40.020
Chapter #0:22: start 5081.201000, end 5211.123000
Metadata:
title : 01:24:41.201
Chapter #0:23: start 5211.123000, end 5359.938000
Metadata:
title : 01:26:51.123
Chapter #0:24: start 5359.938000, end 5833.786000
Metadata:
title : 01:29:19.938
Chapter #0:25: start 5833.786000, end 5953.865000
Metadata:
title : 01:37:13.786
Chapter #0:26: start 5953.865000, end 6229.432000
Metadata:
title : 01:39:13.865
Chapter #0:27: start 6229.432000, end 6534.779000
Metadata:
title : 01:43:49.181
Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s (default)
Metadata:
title : Surround
Stream #0:2(jpn): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s
Metadata:
title : Surround
Stream #0:3(eng): Subtitle: ass (default) (forced)
Stream #0:4(eng): Subtitle: ass
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> hevc (libx265))
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[Parsed_subtitles_3 @ 000002a3e9a96340] libass API version: 0x1701000
[Parsed_subtitles_3 @ 000002a3e9a96340] libass source: commit: 9b3c0d5b350e13eb69dc87b52751ec0ad44280af
[Parsed_subtitles_3 @ 000002a3e9a96340] Shaper: FriBidi 1.0.12 (SIMPLE) HarfBuzz-ng 7.1.0 (COMPLEX)
[Parsed_subtitles_3 @ 000002a3e9a96340] Using font provider directwrite (with GDI)
I should also point out .. as I just tested this ... the files play just fine via the web client in my Opera browser ...
ffmpeg version 5.1.3-Jellyfin Copyright © 2000-2022 the FFmpeg developers
built with gcc 12-win32 (GCC)
configuration: --prefix=/opt/ffmpeg --arch=x86_64 --target-os=mingw32 --cross-prefix=x86_64-w64-mingw32- --pkg-config=pkg-config --pkg-config-flags=--static --extra-libs='-lfftw3f -lstdc++' --extra-cflags=-DCHROMAPRINT_NODLL --extra-version=Jellyfin --disable-ffplay --disable-debug --disable-doc --disable-sdl2 --disable-ptx-compression --disable-w32threads --enable-pthreads --enable-shared --enable-lto --enable-gpl --enable-version3 --enable-schannel --enable-iconv --enable-libxml2 --enable-zlib --enable-lzma --enable-gmp --enable-chromaprint --enable-libfreetype --enable-libfribidi --enable-libfontconfig --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libopenmpt --enable-libwebp --enable-libvpx --enable-libzimg --enable-libx264 --enable-libx265 --enable-libsvtav1 --enable-libdav1d --enable-libfdk-aac --enable-opencl --enable-dxva2 --enable-d3d11va --enable-amf --enable-libmfx --enable-ffnvcodec --enable-cuda --enable-cuda-llvm --enable-cuvid --enable-nvdec --enable-nvenc
libavutil 57. 28.100 / 57. 28.100
libavcodec 59. 37.100 / 59. 37.100
libavformat 59. 27.100 / 59. 27.100
libavdevice 59. 7.100 / 59. 7.100
libavfilter 8. 44.100 / 8. 44.100
libswscale 6. 7.100 / 6. 7.100
libswresample 4. 7.100 / 4. 7.100
libpostproc 56. 6.100 / 56. 6.100
Input #0, matroska,webm, from 'file:H:\Anime Movies\<redacted>.mkv':
Metadata:
CREATION_TIME : 2019-06-15T08:06:07Z
ENCODER : Lavf57.7.2
Duration: 01:48:54.82, start: 0.000000, bitrate: 2709 kb/s
Chapters:
Chapter #0:0: start 0.000000, end 328.537000
Metadata:
title : 00:00:00.000
Chapter #0:1: start 328.537000, end 419.044000
Metadata:
title : 00:05:28.537
Chapter #0:2: start 419.044000, end 916.874000
Metadata:
title : 00:06:59.044
Chapter #0:3: start 916.874000, end 1309.433000
Metadata:
title : 00:15:16.749
Chapter #0:4: start 1309.433000, end 1399.023000
Metadata:
title : 00:21:49.391
Chapter #0:5: start 1399.023000, end 1508.924000
Metadata:
title : 00:23:19.023
Chapter #0:6: start 1508.924000, end 1767.099000
Metadata:
title : 00:25:08.924
Chapter #0:7: start 1767.099000, end 1975.474000
Metadata:
title : 00:29:27.099
Chapter #0:8: start 1975.474000, end 2301.466000
Metadata:
title : 00:32:55.473
Chapter #0:9: start 2301.466000, end 2498.246000
Metadata:
title : 00:38:21.466
Chapter #0:10: start 2498.246000, end 2622.036000
Metadata:
title : 00:41:38.246
Chapter #0:11: start 2622.036000, end 2925.172000
Metadata:
title : 00:43:42.036
Chapter #0:12: start 2925.172000, end 3183.472000
Metadata:
title : 00:48:45.172
Chapter #0:13: start 3183.472000, end 3467.172000
Metadata:
title : 00:53:03.472
Chapter #0:14: start 3467.172000, end 3684.472000
Metadata:
title : 00:57:47.172
Chapter #0:15: start 3684.472000, end 3885.840000
Metadata:
title : 01:01:24.472
Chapter #0:16: start 3885.840000, end 4063.059000
Metadata:
title : 01:04:45.840
Chapter #0:17: start 4063.059000, end 4275.605000
Metadata:
title : 01:07:43.059
Chapter #0:18: start 4275.605000, end 4434.263000
Metadata:
title : 01:11:15.605
Chapter #0:19: start 4434.263000, end 4709.205000
Metadata:
title : 01:13:54.263
Chapter #0:20: start 4709.205000, end 4900.020000
Metadata:
title : 01:18:29.204
Chapter #0:21: start 4900.020000, end 5081.201000
Metadata:
title : 01:21:40.020
Chapter #0:22: start 5081.201000, end 5211.123000
Metadata:
title : 01:24:41.201
Chapter #0:23: start 5211.123000, end 5359.938000
Metadata:
title : 01:26:51.123
Chapter #0:24: start 5359.938000, end 5833.786000
Metadata:
title : 01:29:19.938
Chapter #0:25: start 5833.786000, end 5953.865000
Metadata:
title : 01:37:13.786
Chapter #0:26: start 5953.865000, end 6229.432000
Metadata:
title : 01:39:13.865
Chapter #0:27: start 6229.432000, end 6534.779000
Metadata:
title : 01:43:49.181
Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)
Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s (default)
Metadata:
title : Surround
Stream #0:2(jpn): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s
Metadata:
title : Surround
Stream #0:3(eng): Subtitle: ass (default) (forced)
Stream #0:4(eng): Subtitle: ass
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> hevc (libx265))
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[Parsed_subtitles_3 @ 000002a3e9a96340] libass API version: 0x1701000
[Parsed_subtitles_3 @ 000002a3e9a96340] libass source: commit: 9b3c0d5b350e13eb69dc87b52751ec0ad44280af
[Parsed_subtitles_3 @ 000002a3e9a96340] Shaper: FriBidi 1.0.12 (SIMPLE) HarfBuzz-ng 7.1.0 (COMPLEX)
[Parsed_subtitles_3 @ 000002a3e9a96340] Using font provider directwrite (with GDI)
I should also point out .. as I just tested this ... the files play just fine via the web client in my Opera browser ...