Unable to remove subtitles with ffmpeg

[the_steve_randolph]

As part of a project to learn more about ffmpeg, I have a file that has a subtitle track in the file (I believe the proper term is "embedded subtitle track"). I want to remove that track so that eventually I can hardcode the subtitles. But, I don't seem to be able to remove that subtitle track. I have tried: "-sn" and "-map 0 -map -0: s:1" (space is added to avoid emoji). The original file is an AVI and I have tried removing the track with the following in/out: AVI to AVI, AVI to MKV, AVI to MP4, AVI to MKV to MKV, and, AVI to MKV to MP4. None of these will remove that track. I have also tried "-filter_complex subtitles=in.avi -c: s mov_text -sn" (yes, another space to avoid emoji), but, it does not work either. Here is the basic output for the file:

ffmpeg version 2023-04-26-git-e3143703e9-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      58.  6.100 / 58.  6.100
  libavcodec     60. 10.100 / 60. 10.100
  libavformat    60.  5.100 / 60.  5.100
  libavdevice    60.  2.100 / 60.  2.100
  libavfilter     9.  5.100 /  9.  5.100
  libswscale      7.  2.100 /  7.  2.100
  libswresample   4. 11.100 /  4. 11.100
  libpostproc    57.  2.100 / 57.  2.100
Input #0, avi, from 'in.avi':
  Metadata:
    software        : VirtualDubMod 1.5.10.3 | www.virtualdub-fr.org || (build 2550/release)
  Duration: 01:21:21.60, start: 0.000000, bitrate: 1204 kb/s
  Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 512x384 [SAR 1:1 DAR 4:3], 1066 kb/s, 25 fps, 25 tbr, 25 tbn
  Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 128 kb/s
At least one output file must be specified

I have not used ffmpeg for awhile, but, I have good notes as to what I have learned in the past. I have not had problems with manipulating subtitle tracks before. Again, this is a project to learn about ffmpeg, so, solutions offered here should involve ffmpeg. Thanks.

[zing269]

There is no subtitle track in that file. AVI files do not support subtitles streams, the subtitles you see are "burned in" or "hardcoded".

[the_steve_randolph]

When I play the AVI file in VLC, it shows that there is a subtitle track, and, that I can switch it off with "Disable". My understanding of hardcoded or burned-in was that the subtitles were permantently "burned" into the video stream and were no longer in a separate track.

[poisondeathray]

FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg

What does mediainfo (view=>text) report about subs ?

If you mux in mkvtoolnix does it identify a subtitle track ?

[poisondeathray]

AVI files do not support subtitles streams, the subtitles you see are "burned in" or "hardcoded".

AVI supports subtitle tracks

AVI-Mux GUI can be used to make them, they playback properly as soft subs with MPCHC , potplayer etc...

I posted an example below

You can mux/demux them if they are detected

ffmpeg -i mux.avi

Input #0, avi, from 'mux.avi':
  Metadata:
    software        : AVI-Mux GUI 1.17.8, Aug 30 2008  12:36:58?
    JUNK            :
  Duration: 00:00:05.00, start: 0.000000, bitrate: 259 kb/s
  Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv42
0p, 640x480 [SAR 1:1 DAR 4:3], 25 fps, 25 tbr, 25 tbn
  Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 128 kb/
s
  Stream #0:2: Subtitle: subrip
    Metadata:
      title           : subs

Because ffmpeg detects the subs, they can be stream copied

ffmpeg -i mux.avi -map 0:2 -c:s copy copy.srt

mediainfo also detect them

Text
ID                                       : 2
Duration                                 : 5 s 0 ms
Title                                    : subs

If subs are embedded as closed captions, then you might try ccextractor . I've never seen that with MPEG4 -ASP (XVID)

[netmask56]

A quick and dirty way to extract them if any is pop the file in MKVToolnix and let it produce a mkv file. If you check it with MediaInfo and the file did inded have a subtitle file within it, then you can extract it using for example Inviska MKV Extract or similar. Or simply if you don't need the subtitle after you load the avi file with sub it will show up in MKVToolnix, untick and voila you will have a MKV file sans subs.

[the_steve_randolph]

FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg

If that is true, what does this do?

-filter_complex subtitles=in.mkv -c:s mov_text -sn

or this?

-map 0 -map -0:s:3 -map -0:s:6

[the_steve_randolph]

A quick and dirty way to extract them if any is pop the file in MKVToolnix and let it produce a mkv file. If you check it with MediaInfo and the file did inded have a subtitle file within it, then you can extract it using for example Inviska MKV Extract or similar. Or simply if you don't need the subtitle after you load the avi file with sub it will show up in MKVToolnix, untick and voila you will have a MKV file sans subs.

huh? Please reread my OP.

[the_steve_randolph]

What does mediainfo (view=>text) report about subs ?

If you mux in mkvtoolnix does it identify a subtitle track ?

How will this help me with ffmpeg?

[poisondeathray]

FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg

If that is true, what does this do?

-filter_complex subtitles=in.mkv -c:s mov_text -sn

or this?

-map 0 -map -0:s:3 -map -0:s:6

Did you try it ?

-sn means no subtitle ; as in disregard if there were any

-map refers to selecting of streams , "s" specifically subtitles .

I posted an example above of selecting subs

But if you had multiple sub streams detectable by ffmpeg for that video - it should show up in the console log, the specific numbering could be different for each video . It did not show up for you in post #1, unless you edited it.... Post the full log if you edited it

Look at the ffmpeg documentation for -map options

[poisondeathray]

What does mediainfo (view=>text) report about subs ?

If you mux in mkvtoolnix does it identify a subtitle track ?

How will this help me with ffmpeg?

It will help to determine if there are soft subs. Sometimes a remux into a new container enables ffmpeg to detect them

[the_steve_randolph]

FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg

If that is true, what does this do?

-filter_complex subtitles=in.mkv -c:s mov_text -sn

or this?

-map 0 -map -0:s:3 -map -0:s:6

Did you try it ?

-sn means no subtitle ; as in disregard if there were any

-map refers to selecting of streams , "s" specifically subtitles .

I posted an example above of selecting subs

But if you had multiple sub streams detectable by ffmpeg for that video - it should show up in the console log, the specific numbering could be different for each video . It did not show up for you in post #1, unless you edited it.... Post the full log if you edited it

Look at the ffmpeg documentation for -map options

You have misunderstood my post. You said "FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg". I posted examples of switches used in an ffmpeg command line that deal with subtitles.

[poisondeathray]

You have misunderstood my post. You said "FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg". I posted examples of switches used in an ffmpeg command line that deal with subtitles.

You've misunderstood everyone's post(s)

FFmpeg does not detect subtitles on your specific video in post #1 . Look at the console log

Of course ffmpeg can detect subs on videos that actually have subs. ( I posted an example where ffmpeg could copy subs with an actual video example ...look at post#5)

So ... "If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg" - is it clear now ?

[the_steve_randolph]

FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg

If that is true, what does this do?

-filter_complex subtitles=in.mkv -c:s mov_text -sn

or this?

-map 0 -map -0:s:3 -map -0:s:6

Did you try it ?

-sn means no subtitle ; as in disregard if there were any

-map refers to selecting of streams , "s" specifically subtitles .

I posted an example above of selecting subs

But if you had multiple sub streams detectable by ffmpeg for that video - it should show up in the console log, the specific numbering could be different for each video . It did not show up for you in post #1, unless you edited it.... Post the full log if you edited it

Look at the ffmpeg documentation for -map options

Yes, I have tried those switches and they worked.

[the_steve_randolph]

FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg

If that is true, what does this do?

-filter_complex subtitles=in.mkv -c:s mov_text -sn

or this?

-map 0 -map -0:s:3 -map -0:s:6

Did you try it ?

-sn means no subtitle ; as in disregard if there were any

-map refers to selecting of streams , "s" specifically subtitles .

I posted an example above of selecting subs

But if you had multiple sub streams detectable by ffmpeg for that video - it should show up in the console log, the specific numbering could be different for each video . It did not show up for you in post #1, unless you edited it.... Post the full log if you edited it

Look at the ffmpeg documentation for -map options

I understand what I posted. I posted examples of where ffmpeg understood and dealt with subtitles.

[the_steve_randolph]

You have misunderstood my post. You said "FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg". I posted examples of switches used in an ffmpeg command line that deal with subtitles.

You've misunderstood everyone's post(s)

FFmpeg does not detect subtitles on your specific video in post #1 . Look at the console log

Of course ffmpeg can detect subs on videos that have subs. ( I posted an example where ffmpeg could copy subs with an actual video example ...)

So, does that mean that ffmpeg doesn't understand subtitles, even though I have posted examples of switches that work with ffmpeg?

[poisondeathray]

You have misunderstood my post. You said "FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg". I posted examples of switches used in an ffmpeg command line that deal with subtitles.

You've misunderstood everyone's post(s)

FFmpeg does not detect subtitles on your specific video in post #1 . Look at the console log

Of course ffmpeg can detect subs on videos that have subs. ( I posted an example where ffmpeg could copy subs with an actual video example ...)

So, does that mean that ffmpeg doesn't understand subtitles, even though I have posted examples of switches that work with ffmpeg?

It means ffmpeg can handle soft subs, if it detects soft subs . Such as the example I posted. Try it.

If ffmpeg does not detect soft subs, such as your video in post #1, it will not work with the subs

[the_steve_randolph]

You have misunderstood my post. You said "FFmpeg does not detect subtitles track. If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg". I posted examples of switches used in an ffmpeg command line that deal with subtitles.

You've misunderstood everyone's post(s)

FFmpeg does not detect subtitles on your specific video in post #1 . Look at the console log

Of course ffmpeg can detect subs on videos that have subs. ( I posted an example where ffmpeg could copy subs with an actual video example ...)

So, does that mean that ffmpeg doesn't understand subtitles, even though I have posted examples of switches that work with ffmpeg?

It means ffmpeg can handle soft subs, if it detects soft subs . Such as the example I posted. Try it.

If ffmpeg does not detect soft subs, such as your video in post #1, it will not work with the subs

So, basically, you have narrowed down the purpose of my thread. What is going on with my file and what can I do with it with ffmpeg?

[poisondeathray]

What is going on with my file and what can I do with it with ffmpeg?

Probably nothing with ffmpeg alone in terms of the "subtitles"

Some other suggestions were given for other programs - that might enable ffmpeg to handle it for that specific video

[ProWo]

As part of a project to learn more about ffmpeg, I have a file that has a subtitle track in the file (I believe the proper term is "embedded subtitle track"). I want to remove that track so that eventually I can hardcode the subtitles. But, I don't seem to be able to remove that subtitle track. I have tried: "-sn" and "-map 0 -map -0: s:1" (space is added to avoid emoji). The original file is an AVI and I have tried removing the track with the following in/out: AVI to AVI, AVI to MKV, AVI to MP4, AVI to MKV to MKV, and, AVI to MKV to MP4. None of these will remove that track.
I have not used ffmpeg for awhile, but, I have good notes as to what I have learned in the past. I have not had problems with manipulating subtitle tracks before. Again, this is a project to learn about ffmpeg, so, solutions offered here should involve ffmpeg. Thanks.

I think these are EIA 608/708 captions.
They are not displayed by ffmpeg, but mediainfo does.
You can extract them with clever FFmpeg-GUI.

[Swedaniel]

As part of a project to learn more about ffmpeg, I have a file that has a subtitle track in the file (I believe the proper term is "embedded subtitle track"). I want to remove that track so that eventually I can hardcode the subtitles. But, I don't seem to be able to remove that subtitle track. I have tried: "-sn" and "-map 0 -map -0: s:1" (space is added to avoid emoji). The original file is an AVI and I have tried removing the track with the following in/out: AVI to AVI, AVI to MKV, AVI to MP4, AVI to MKV to MKV, and, AVI to MKV to MP4. None of these will remove that track. I have also tried "-filter_complex subtitles=in.avi -c: s mov_text -sn" (yes, another space to avoid emoji), but, it does not work either. Here is the basic output for the file:


I have not used ffmpeg for awhile, but, I have good notes as to what I have learned in the past. I have not had problems with manipulating subtitle tracks before. Again, this is a project to learn about ffmpeg, so, solutions offered here should involve ffmpeg. Thanks.

Hi, if there is no other solution maybe the program Metadata++ can help out, it use FFMpeg, ImageMagick, FFProbe, ExifTool! Im not sure if it can remove embedded subtitles, i could not find an video to test it with since i dont have one with embedded subtitle, but the program seem to be able to remove basicly anything from an video! Im new to the program myself so if it can get the job done im not sure as ive only used it 2 times yet myself to delete some stubborn metadata! Maybe worth checking out if there is no other solution with the softwares you allready have!

If you can convert the video to MP4 and the subtitle is still there, maybe mp4ui can help out, it can atleast import alot of stuff as an track into the videos, im not sure if it can find subtitles and have them deleted tough, since i dont have one to try with!

Edit: If decide to use the mp4ui (if it even can get the job done) it will add "Encoded by" metadata to your mp4, the stubborn type so you might want to check in with the Metadata++ to have it removed if using the program!

[the_steve_randolph]

I think these are EIA 608/708 captions.
They are not displayed by ffmpeg, but mediainfo does.
You can extract them with clever FFmpeg-GUI.

Subtitles do not show up in either of these two apps. But, again, this is a project to learn more about ffmpeg. Do you have any information as to what is going on with ffmpeg with this file?

[the_steve_randolph]

Hi, if there is no other solution maybe the program Metadata++ can help out, it use FFMpeg, ImageMagick, FFProbe, ExifTool! Im not sure if it can remove embedded subtitles, i could not find an video to test it with since i dont have one with embedded subtitle, but the program seem to be able to remove basicly anything from an video! Im new to the program myself so if it can get the job done im not sure as ive only used it 2 times yet myself to delete some stubborn metadata! Maybe worth checking out if there is no other solution with the softwares you allready have!

If you can convert the video to MP4 and the subtitle is still there, maybe mp4ui can help out, it can atleast import alot of stuff as an track into the videos, im not sure if it can find subtitles and have them deleted tough, since i dont have one to try with!

Edit: If decide to use the mp4ui (if it even can get the job done) it will add "Encoded by" metadata to your mp4, the stubborn type so you might want to check in with the Metadata++ to have it removed if using the program!

Please reread my OP that you quoted.

[the_steve_randolph]

So ... "If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg" - is it clear now ?

Yes, and, THAT is the purpose of this thread. WHY is ffmpeg not finding these subtitles? Other apps are not seeing them either.

[lollo]

Hi, if there is no other solution maybe the program Metadata++ can help out, it use FFMpeg, ImageMagick, FFProbe, ExifTool! Im not sure if it can remove embedded subtitles, i could not find an video to test it with since i dont have one with embedded subtitle, but the program seem to be able to remove basicly anything from an video! Im new to the program myself so if it can get the job done im not sure as ive only used it 2 times yet myself to delete some stubborn metadata! Maybe worth checking out if there is no other solution with the softwares you allready have!

If you can convert the video to MP4 and the subtitle is still there, maybe mp4ui can help out, it can atleast import alot of stuff as an track into the videos, im not sure if it can find subtitles and have them deleted tough, since i dont have one to try with!

Edit: If decide to use the mp4ui (if it even can get the job done) it will add "Encoded by" metadata to your mp4, the stubborn type so you might want to check in with the Metadata++ to have it removed if using the program!

Please reread my OP that you quoted.

Swedaniel is not real, is a sort of "bugged" software writing some (useless) words in reply to few keywords found in the posts.

[the_steve_randolph]

OK, since we can't seem to find an answer with ffmpeg, I have tried some other apps to try to locate the subtitle track. These viewers do not see the subtitle track: PotPlayer, Windows Media Player, Nero ShowTime, and, Zoom Player. These apps do not show the track either: MediaInfo, Photoshop Premiere 14, HandBrake, clever FFMPEG GUI, and, Subtitle Edit. It seems that VLC is the only app that sees the track. The actual subtitles do match the video, so, the track is not some random track included by accident.

I am willing to look at a few other apps to see if any of them can see the track and/or to identity apps that can create this phantom track. But, again, this is a project to learn more about ffmpeg. I understand the idea that ffmpeg cannot do everything, but, I think that we should be able to identify where this track is inside of the file and why no app other than VLC sees it.

[poisondeathray]

Does VLC give you any more information about the subs in the codec information or media information tabs?

[the_steve_randolph]

Does VLC give you any more information about the subs in the codec information or media information tabs?

Under the Codec tab, it shows:

Stream 2:
Codec: Text subtitles with various tags (subt)
Type: Subtitle

ffmpeg does not show that stream.

When I try to remove this track as closed captioning with "-bsf:v "filter_units=remove_types=6" I get the error message "Codec 'mpeg4' (12) is not supported by the bitstream filter 'filter_units'". Then, when I try to export as closed captioning with "-map 0: s:0" {yes, space added to avoid emoji}, I get the error message "Stream map '0: s:0' {yes, space added to avoid emoji} matches no streams". So, I guess that means that at least as far as ffmpeg is concerned, that track is not closed captioning.

I also found the command:

ffmpeg -f lavfi -i movie=in.mp4[out0+subcc] -vn -an -codec:s subrip b.srt

And the resulting output was:

ffmpeg version 2023-04-26-git-e3143703e9-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      58.  6.100 / 58.  6.100
  libavcodec     60. 10.100 / 60. 10.100
  libavformat    60.  5.100 / 60.  5.100
  libavdevice    60.  2.100 / 60.  2.100
  libavfilter     9.  5.100 /  9.  5.100
  libswscale      7.  2.100 /  7.  2.100
  libswresample   4. 11.100 /  4. 11.100
  libpostproc    57.  2.100 / 57.  2.100
Input #0, lavfi, from 'movie=in.avi[out0+subcc]':
  Duration: N/A, start: 0.040000, bitrate: N/A
  Stream #0:0: Video: wrapped_avframe, yuv420p, 512x384 [SAR 1:1 DAR 4:3], 25 fps, 25 tbr, 25 tbn
  Stream #0:1: Subtitle: eia_608
Output #0, srt, to 'b.srt':
  Metadata:
    encoder         : Lavf60.5.100
  Stream #0:0: Subtitle: subrip
    Metadata:
      encoder         : Lavc60.10.100 subrip
Stream mapping:
  Stream #0:1 -> #0:0 (eia_608 (cc_dec) -> subrip (native))
Press [q] to stop, [?] for help
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
[Parsed_movie_0 @ 000001cf697575c0] EOF timestamp not reliable
[out#0/srt @ 000001cf697a1780] video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[out#0/srt @ 000001cf697a1780] Output file is empty, nothing was encoded(check -ss / -t / -frames parameters if used)
size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A

But, the resulting b.srt was empty.

So, it seems that ProWo was right in that the stream/track is "eia_608". Now, what does that mean? Do I need a newer version of ffmpeg?

I also found this info but the meaning is above my paygrade:

EIA-608 and similar closed captioning standards, the captions are
embedded directly in the video bitstream as user data. H.264 
bitstreams are stored as a sequence of NAL (network abstraction layer)
units. Each unit has a type; user data is stored in a NAL unit of the
supplemental enhancement information (SEI) type.

OK, I downloaded the current version of Clever FFMpeg GUI and it is able to see the EIA-608 stream. I was able to extract it (which I don't need) and it was also able to extract the file into separate audio and video files. Playing the extracted video file, the EIA-608 stream is removed, so, I can use the two files to merge again with ffmpeg. But, when I merge the audio and video files back with ffmpeg, the closed captioning stream reappears. But, as stated in the OP, this thread is to understand why ffmpeg is having problems with this stream/track.

Also, when I try using "-bsf:v filter_units=remove_types=6" it gives me the error message:

Codec 'mpeg4' (12) is not supported by the bitstream filter 'filter_units'.  Supported codecs
are: av1 (226) h264 (2) hevc (173) mpeg2video (2) vp9 (167)

Again, the meaning of that message is above my paygrade. I also found something that said to remove the EIA-608 stream, use the "filter_units" switch but use the number 178 instead of 6. Changing that number still generates that error message.

[ProWo]

-bsf:v filter_units=remove_types=6

works with a h264 (avc) video (tested).
For mpeg4 (divx, xvid) you seem to be out of luck.
I would still experiment with other numbers.

[Crunchedfire]

So ... "If ffmpeg can't detect the subs, you can't "remove" or stream copy them with ffmpeg" - is it clear now ?

Yes, and, THAT is the purpose of this thread. WHY is ffmpeg not finding these subtitles? Other apps are not seeing them either.

Hi, since it seem like an weird issue, if using VLC Media Player, if you have for example an folder named "Subtitles" in the same directory as the video, and allso if the subtitle name have the same name as the video it will appear as an subtitle stream within vlc! If maybe you have many folders and videos in this directory that the video is inside maybe you used the same name as an subtitle without knowing and have an folder with many subtitles!

For me it say:
Stream 0
Codec: Text subtitles with various Tags (subt)
Language: \subtitles\subtitlename
Type: Subtitle

This is from vlc, the folder named "Subtitles" is in the same directory as the avi video and in this directory the subtitle have the same name as the video, VLC Media Player picked the subtitle up by itself! The subtitle allso show up as an subtitle track that can be disabled!