removing all metadata from mp4 and mkv files recursively without creating copies and re-encoding

aristosv · 10-17-2019, 11:47 AM

I have a directory containing about 300 video files, mostly mp4 and mkv files, each one in its own directory.

I am looking for a way to remove the metadata information from all the video files, without having to re-encode them, and without having to make copies for each file.

They are on a NAS with very slow disks, and re-encoding will take ages.

exiftool doesn't work on mkv files and it actually takes ages on each file, I guess it re-encodes each file. ffmpeg also tries to re-encode and I haven't found a way to use it without creating a copy of each file.

Anyone done this before? Any ideas?

Firerat · 10-17-2019, 11:50 AM

mkvpropedit

that will add/change/delete metadata in mkv

Edit:
Just as a side note, if you are serving files via dlna , it may also be providing metadata from the files or some scrapper, its cache may need to be purged.

JeremyBoden · 10-18-2019, 09:13 AM

Would you trust a program that changes a video file in situ?

I think you need to transfer the file to a PC, generate the new file, check it still works, then transfer it back to the NAS.
Both mp4 & mkv are containers so no re-muxing would be needed.

Try

Code:

ffmpeg -i input-file.mp4 -map_metadata -1 -c:v copy -c:a copy   output-file.mp4

I tried it on a 1GB (one hour) video file and it took about 10 seconds to strip all metadata and create a new video.
If you need to keep the title, you will have to add it back in.

[See https://superuser.com/questions/4413...s-with-ffmpeg]

Should also work for mkv - but I haven't tried it.

aristosv · 10-18-2019, 09:15 AM

Is there a way I can do this without copying the file?

Firerat · 10-18-2019, 09:27 AM

Quote:

Originally Posted by aristosv

Is there a way I can do this without copying the file?

mkvpropedit can add/change/delete metadata

wait, .. didn't I already mention this ?

aristosv · 10-18-2019, 09:28 AM

I meant using @JeremyBoden suggestion.

Firerat · 10-18-2019, 09:31 AM

Quote:

Originally Posted by aristosv

I meant using @JeremyBoden suggestion.

which is pointless if mkvpropedit and exiftool can modify the metadata

JeremyBoden · 10-18-2019, 09:59 AM

If you have valuable videos, I'd suggest you make sure you have reliable backups before trying an edit in situ.

HappyTux · 10-20-2019, 10:52 AM

Quote:

Originally Posted by aristosv

Is there a way I can do this without copying the file?

What I use for them annoying titles that are some of the time embedded in the videos. You could modify the script to your needs.

Code:

MacUser2525:~$ cat Bin/title.sh 
#!/bin/bash

# Get directory script is running in
DIR="$(dirname "$PWD")/$(basename "$PWD")"

# Change to directory
cd $DIR

# Now process all .mkv files under that directory
for i in $(find $PWD | grep .mkv ); do

	# Name of file to use in title delete
	NAME=$(basename "$i")
	echo $NAME
	mkvpropedit "$i" -d title
#	mkvpropedit "$i" -d artist
#   mkvpropedit -v movie.mkv -v --edit track:2 --set track-number=3 --edit track:3 --set track-number=2 # set track 3 to first audio delete removes track
#   https://www.bunkus.org/videotools/mkvtoolnix/doc/mkvpropedit.html

# Done processing all files
done

And contrary to the paranoid thinking, the changing of the metadata does not effect the files in any way.