xfce4 and Thinar compatible

[guglovich]

Description:

The file /usr/share/thumbnailers/ffmpegthumbnailer.thumbnailer ships with the -f flag in the Exec line:

Exec=ffmpegthumbnailer -i %i -o %o -s %s -f

The -f flag forces ffmpegthumbnailer to overwrite the output file but skips writing the required PNG metadata fields (Thumb::URI, Thumb::MTime) defined by the freedesktop Thumbnail Managing Standard.

As a result, Thunar (via tumblerd) rejects all generated video thumbnails as invalid and refuses to display them. The issue affects all users of Thunar/XFCE with tumbler on Arch Linux. GNOME and KDE are unaffected because they use their own thumbnailing pipelines that do not rely on .thumbnailer files.

The fix is to remove the -f flag:

Exec=ffmpegthumbnailer -i %i -o %o -s %s

Steps to reproduce:

1. Install ffmpegthumbnailer and tumbler on Arch Linux with XFCE/Thunar
2. Open a folder containing video files in Thunar
3. No video thumbnails are generated
4. Workaround: disable [FfmpegThumbnailer] plugin in ~/.config/tumbler/tumbler.rc (Disabled=true) and remove the -f flag from /usr/share/thumbnailers/ffmpegthumbnailer.thumbnailer — thumbnails start working correctly after clearing ~/.cache/thumbnails/ and rebooting

[dirkvdb]

the -f options is used for overlaying the filmstrip. There is no conditional logic for when to write the png tags. So I'm not sure your analysis is correct.

[guglovich]

But it worked for me right away. I wrote a reproduction. Overall, I found the solution in a video on the internet + there were two articles with the same fix specifically for xfce4. There are even guides with this method.