Remove closed caption from mkv

[arktay]

Hi guys, I 'm reordering my Plex library and i noticed that plex shows closed caption in the subtitle list as they were normal subtitles.
I read that closed caption are part of the video stream, so with tools like mkvtoolnix you can't remove them. Is there a way to remove them from the video stream without re-encoding it? I also found out that restream allows to do this, but it's outdated and works only with MPEG-2 format.

[usually_quiet]

Hi guys, I 'm reordering my Plex library and i noticed that plex shows closed caption in the subtitle list as they were normal subtitles.
I read that closed caption are part of the video stream, so with tools like mkvtoolnix you can't remove them. Is there a way to remove them from the video stream without re-encoding it? I also found out that restream allows to do this, but it's outdated and works only with MPEG-2 format.

It may be possible to remove them using Hybrid. See https://forum.videohelp.com/threads/390217-Deleting-CEA-608-(EIA-608)-captions-from-a-...le#post2561602

[arktay]

I tried Hybrid following all the stpes but didn't work. Scrolling up i saw a simple ffmpeg line that actually worked!
Also hybrid seems such a powerful tool for aything else.
Thanks!

[Cornucopia]

"Closed" captions mean they aren't visible until you turn them on. So turn them off.

If they are "Open" captions, otoh, aka hard-subs, you are stuck with them unless you want to go to the trouble of blur filtering, overlaying, temporal smear, etc. None of which will fully remove them without also removing or adversely altering the picture.

Scott

[usually_quiet]

"Closed" captions mean they aren't visible until you turn them on. So turn them off.

If they are "Open" captions, otoh, aka hard-subs, you are stuck with them unless you want to go to the trouble of blur filtering, overlaying, temporal smear, etc. None of which will fully remove them without also removing or adversely altering the picture.

Scott

That isn't what is going on. The problem is that both regular subtitles and closed captions are automatically detected by Plex and appear on the list of available subtitles presented by its media player but arktay only wants the regular subtitles to be shown on the list.

[netmask56]

Hi guys, I 'm reordering my Plex library and i noticed that plex shows closed caption in the subtitle list as they were normal subtitles.
I read that closed caption are part of the video stream, so with tools like mkvtoolnix you can't remove them. Is there a way to remove them from the video stream without re-encoding it? I also found out that restream allows to do this, but it's outdated and works only with MPEG-2 format.

You wrote "I read that closed caption are part of the video stream, so with tools like mkvtoolnix you can't remove them." The operative word for me is "I read" have you actually tried? If not try remuxing in MKVToolNix and untick all subtitles. If you need subs then you can always extract the ones you need from the original file and use it as an external sub.

[jagabo]

I read that closed caption are part of the video stream, so with tools like mkvtoolnix you can't remove them.

Broadcast analog TV embeded the closed caption signal at the top of the frame -- outside the visible part of the picture:


[Attachment 52622 - Click to enlarge]

The TV would then decode that signal and overlay CC text onto the visible part of the picture. Some capture cards capture enough of the frame to include the lines with the CC signal. Of course, if you're recording from a device that is overlaying CC text, that text is burned into the picture. Remuxing will not get rid of them.

In modern digital broadcast closed captions are just another digital data stream muxed with the video and audio streams. This soft CC data can be removed with a remux.

[arktay]

Unticking all subtitles with mkvtoolnix does not remove closed caption

set str=ffmpeg -i "input" -bsf:v "filter_units=remove_types=6" -c copy "output"

I think this line removes closed caption without altering the picture since it process the output very fast and the filesize is almost the same

[usually_quiet]

There are two styles of digital closed captions present in N. American digital TV signals, CEA-708 and CEA-608. NTSC DVD closed captioning is similar to CEA-608. CEA-708 includes more character sets and positioning options but as I recall, every software player that I have used is only aware of CEA-608 closed captions, which are a replacement for the old analog closed captions.

I want to keep CEA-608 closed captions if they are present in my recorded TV shows, so I had to figure out what preserves them and what strips them. (I use CCs when I turn the sound down to avoid disturbing others so that I can still follow the dialog.) In my recordings of both OTA broadcasts and digital cable TV, CEA-608 closed caption data is stored in the video stream's GOP user data. Demuxing or remuxing doesn't usually remove it. Re-encoding does remove it most of the time.(VideoReDo TV Suite is the only program that I have used that is able to re-encode video and still preserve the closed captions.)

[Simon_Haddad]

(VideoReDo TV Suite is the only program that I have used that is able to re-encode video and still preserve the closed captions.)

FFmpeg preserves closed caption data if you're using the libx264 encoder with the -a53cc true option. (VideoReDo TV Suite uses FFmpeg IIRC)


https://ffmpeg.org/ffmpeg-all.html#Options-29

[Pusat]

I separated video audio and subtitles with Inviska MKV Extract, then merged them with MKV Muxing Batch GUI v2.3 but this closed captions curse didn't go away. Is there an easier way to delete it, a new updated way. I don't want to see it in the subtitles section on VLC.

[ProWo]

For x264 video use:

ffmpeg -i input.mkv -codec copy -bsf:v "filter_units=remove_types=6" output.mkv

For mpeg2 video use
remove_types=178

To extract them use clever ffmpeg-GUI.

[Pusat]

thank you a lot for your reply. but unfortunately I don't know using these codes. I only am good at using softwares. like Inviska MKV Extract, JMkvpropedit 1.5.2, MKV Muxing Batch GUI v2.3, MKVToolNix GUI v74.0.0. Is there any way to solve this issue with any of these softwares or other than that similar to these? Or I need a video to show me how to do what you said.

[ProWo]

Will reply tomorrow

[Pusat]

ok. thank you. I'll look tomorrow.

[ProWo]

ok. thank you. I'll look tomorrow.

Post a mediainfo report (text mode) from your mkv here meanwhile.

[ProWo]

@Pusat
First of all:
Download ffmpeg for your operating system.
For x64: https://www.videohelp.com/download/ffmpeg-6.0-full_build.7z
For x86: https://github.com/sudo-nautilus/FFmpeg-Builds-Win32/releases/download/latest/ffmpeg-m...gpl-shared.zip

Extract the files to C:\ffmpeg
The final folder structure should be C:\ffmpeg\bin (and other folders and files)

Copy your mkv video into the bin folder.

1.Click the Windows Start button.
2. Type in "Command Prompt".
3. Right click on Command Prompt and click "Run as administrator".
4. Click Yes if the Windows User Account Control prompt is displayed.

A black command line window opens.
Write here:

cd c:\ffmpeg\bin

and hit the enter (return) key.
On the left shold be diplayed

c:\ffmpeg\bin

now.

If so, write:

ffmpeg -i input.mkv -map 0 -codec copy -bsf:v "filter_units=remove_types=6" output.mkv

(You can also copy the command into the command line window. Rename input.mkv to the name of your video.
If the name contains spaces, you have to put them in quotes, e.g. "My personal video.mkv").

If finished, you'll find the new video file output.mkv into the bin folder. The captions should be gone now.

[Pusat]

Dear ProWo I just saw your reply. I'll try this as soon as poosible after work hours and I'll write to you. Thank you a lot.

[Pusat]

@ProWo Sorry for being late. I tried it now. I did all the required things as you told but it says:


[Attachment 71035 - Click to enlarge]

[ProWo]

@Pusat
I wrote in post #17:

Rename input.mkv to the name of your video.
If the name contains spaces, you have to put them in quotes, e.g. "My personal video.mkv"

So you must use

ffmpeg -i test.mkv -map 0 -codec copy -bsf:v "filter_units=remove_types=6" output.mkv

if your video file name is test.mkv.
unfortunately, you have turned off the display of file extensions in windows explorer, so you can't see it.
See here: https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/How-...n-Windows.html

[Pusat]

@ProWo

there's no space in the file name. It's only "test"
yes displaying of file extensions was turned off and after you told this I turned it on. But still ffmpeg can not see the file. I don't know why?

[ProWo]

You must replace input.mkv with test.mkv and the final test.mkv with output.mkv

[Pusat]

Dear @ProWo I made the correction you mentioned in the command line.
Now it seems to try to create a new mkv file but the size is only 1 KB and the text you see in the screenshot appears. What could be the problem?


[Attachment 71049 - Click to enlarge]

[ProWo]

Your video is x265 (hevc), not x264 (avc), so the command can not work.
I must investigate further and will come back to you later.

[Pusat]

ok thank you.

this was mp4 I converted it to mkv with mkvtoolnix. this may be the reason. I don't know. This isn't the video that I want to make changes on it. I just wanted to try this command. I have other mkv files for tv shows.

Anyway, if this is the way to remove close captions it will be useful for me for other videos.

[ProWo]

This should work for your test.mkv (hevc):

ffmpeg -i test.mkv -map 0 -codec copy -bsf:v filter_units=remove_types=39 output.mkv