[digiKam-users] Reading/writing Video metadata to Caption/Title

[John Bray-2]

Would it be possible to extend the Metadata/Advanced configuration
options to read/write video, especially avi and mp4, metadata to
Captions/Captions or Title.

I currently use external scripts to do

exiftool -Title="title" file.mp4
mencoder oldfile.avi -oac pcm -ovc copy -info name="name" -info
subject="subject" -info comment="title" -o newfile.avi
ffmpeg -i oldfile.mp4 -metadata title="title" -metadata
comment="comment" newfile.mp4
ffmpeg -i oldfile.avi -metadata title="title" -metadata
comment="comment" newfile.avi

And I see that digkam 6.0.0 now supports ffmpeg, so it should be straightforward

Currently it seems that the Captions Caption/Title information seems
trapped inside Digikam's database, and is never read or written to
files.

Thanks

John

[AndriusWild]

Problem with ffmpeg is that it always produces an output file. So, for example, from file.mp4 digiKam will have to create file_out.mp4, then remove file.mp4 then rename file_out.mp4 to file.mp4. I think Gilles tested it and it slowed down the application a lot (too much).

Maybe one day someone will write a plugin for that. In that case only the users who want write to video files will install and activate the plugin. I am one of them too. So I might chip in into the development if I understand how the new plugin interface works.

Sent from my Samsung Galaxy smartphone.

-------- Original message --------

From: John Bray <[hidden email]>

Date: 2019-03-10 9:55 AM (GMT-07:00)

To: [hidden email]

Subject: [digiKam-users] Reading/writing Video metadata to Caption/Title

Would it be possible to extend the Metadata/Advanced configuration
options to read/write video, especially avi and mp4, metadata to
Captions/Captions or Title.

I currently use external scripts to do

exiftool -Title="title" file.mp4
mencoder oldfile.avi -oac pcm -ovc copy -info name="name" -info
subject="subject" -info comment="title" -o newfile.avi
ffmpeg -i oldfile.mp4 -metadata title="title" -metadata
comment="comment" newfile.mp4
ffmpeg -i oldfile.avi -metadata title="title" -metadata
comment="comment" newfile.avi

And I see that digkam 6.0.0 now supports ffmpeg, so it should be straightforward

Currently it seems that the Captions Caption/Title information seems
trapped inside Digikam's database, and is never read or written to
files.

Thanks

John

[Gilles Caulier-4]

Le lun. 11 mars 2019 à 14:16, Andrey Goreev <[hidden email]> a écrit :

Problem with ffmpeg is that it always produces an output file. So, for example, from file.mp4 digiKam will have to create file_out.mp4, then remove file.mp4 then rename file_out.mp4 to file.mp4. I think Gilles tested it and it slowed down the application a lot (too much).

For reading, we use the 'information' mode from ffmpeg to extra metadata only. Something similar to "ffmpeg -i" but working with ffmpeg shared library.

For writing, metadata can be only update on few video format (typically mostly MP4), and for a few metadata entry.

I use it at work to tag MP4 files written from a IR video recorder, but it's really a limited way. ffmpeg infrastructure have not been designed for this kind of job. And yes, ffmpeg generate an output file by this way.

Maybe one day someone will write a plugin for that. In that case only the users who want write to video files will install and activate the plugin. I am one of them too. So I might chip in into the development if I understand how the new plugin interface works.

The plugin interface is not yet able to work with low level metadata component. 

Best

Gilles Caulier