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How can I remove all metadata from all formats via FFmpeg?

I can just set special metadata for each format per man ffmpeg. Any option or method to clear all metadata and strip media from all metadata available on ffmpeg?

   -metadata key=value
       Set a metadata key/value pair.

       For example, for setting the title in the output file:

               ffmpeg -i in.avi -metadata title="my title" out.flv
slhck
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Mohammad Hossein Fattahizadeh
  • 1,119

5 Answers5

125

Slightly modifying the command line by @izx, I got this:

ffmpeg -i in.mov -map_metadata -1 -c copy out.mov

The result is (again, checked with exiftool), a metadata record reduced from 81 to 52 lines. Note that you can't simply remove all metadata, some things will stay.

Note that the above command only copies the first audio, video, and subtitle streams. If you want to copy all streams, add the option -map 0:

ffmpeg -i in.mov -map_metadata -1 -c copy -map 0 out.mov

If you want to remove the newly added encoder field, add this to the command (before the output filename):

-fflags +bitexact -flags:v +bitexact -flags:a +bitexact

Thanks to @wisbucky for the hint.

If you want to actually change/overwrite a field, e.g. the generated title, you need to set:

-metadata title="Some Value"

However, I didn't get the creation date to change, which is strange because it seemed to work in the Ubuntu version. I posted on the FFmpeg mailing list, asking whether there were any updates or comments on that, but there was no answer.

slhck
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17

NOTE: I have since updated ffmpeg (previously I had the outdated version of avconv from the Ubuntu repositories).

Now @slhck's -map_metadata -1 works perfectly.

I recommend @slhck's solution because it's less typing and up to date. I'm leaving this here for anyone using an outdated version.

The easiest way to do this is to set -map_metadata to use one of the input streams, rather than using global metadata. 99% of the time this should work. NOTE: I'm using avconv, because that's in the Ubuntu 12.04 repositories; this will probably be drop-in compatible with ffmpeg, since their syntax always is in my experience.

avconv -i input.mp4 -map 0 -map_metadata 0:s:0 -c copy output.mp4

This will take the metadata from the first data stream (normally the video stream) and use that to replace the global metadata of the container file. This works because most of the time, the data streams have no meaningful metadata written to them; however, sometimes they do, and you want to completely get rid of that metadata. Unfortunately, the only way I can think of to do this used a pipe and two avconv processes.

avconv -i input.mp4 -f wav - | avconv -i - -i input.mp4 -map 1 -map_metadata 0 -c copy output.mp4

This takes advantage of the fact that WAV files can't contain metadata (since the format was created before metadata tags existed).

Both of these methods blanked all metadata on a file I just tested them on - all that exiftool reported on was the codec information, and avprobe reported no metadata to me. Using a pipe for this is pretty ugly, and the first method will work in 99% of cases, so that should be preferred.

RobertL
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evilsoup
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15

My solution to strip metadata, chapters, to change creation time and title. This way any metacontent should be different from the original file:

ffmpeg -y -i "test.mkv" -c copy -map_metadata -1 -metadata title="My Title" -metadata creation_time=2016-09-20T21:30:00 -map_chapters -1 "test.mkv"
shub
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7

To strip metadata, I use -map_metadata:g -1 because I only strip the global metadata and keep the subtitles's metadata such as the track language names :

$ ffmpeg -hide_banner -i "$video" -map 0:v:0? -map 0:a? -map 0:s? -c copy -map_metadata:g -1 "$outputVideo"

The -map 0:...? option argument means that (according to man ffmpeg) :

A trailing "?" after the stream index will allow the map to be optional: if the map matches no streams the map will be ignored instead of failing.

SebMa
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0

This might not be very useful for a lot of people (due to transcoding and the size of the intermediate file). But for some use-cases this might be a useful approach. The idea is to decode the image/video to a y4m file (raw pixel data). And re-encode it back. That first step strips ALL the metadata.

ffmpeg -i foo.jpg bar.y4m
ffmpeg -i bar.y4m bar.jpg
rm bar.y4m

What I like about this is that it's super easy to remember the command. But remember, transcoding takes time and adds more distortion to the signal. The intermediate file will be also super huge if you do it on video. But if you don't care about these limitations, go for it ;)

Dimitri Podborski
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