Write protected tags

[Neuston]

i noticed that some tags are read only. i tryied to write them anyway  and i got this message "the [TAG] doesn't exist or isn't writable".

my question :
is it protected by the video owner (i didn't  ) or camera device? by which method ?
or simply exiftool didn#t implement code for editing that specific TAG ? how can i add that ?

NB: trying to update GoPro mp4 metadata

regards,
Hatem

[Phil Harvey]

Hi Hatem,

Only a small number of tags are writable in video files by ExifTool, mainly for technical reasons since the video format landscape resembles a muddy mine field.

For writing video files, ffmpeg is probably the way to go.

- Phil

[StarGeek]

To clarify, it's not possible to write protect metadata.  Exiftool doesn't have the code to write those tags. 

As an example of how much of a mess the video situation is, Phil had to add some 20+ variations on just extracting a GPS track from videos.  And I recall one case of exiftool messing up one person's video (Phil was able to fix it) because the video was encoded differently from every other video.

[Neuston]

  thanks anyway.
i need to gather some knowledge about metadata stuff now.
i gived ffmpeg a try it seems to run for long time then don't update the wanted TAGS, even no warning or info shown about it's failure.

[StarGeek]

Make sure you're copying streams and not re-encoding.  Search around for the options but it's usually something along these lines
ffmpeg -i infile.mp4 -vcodec copy -acodec copy -metadata title="New Title" outfile.mp4