ffmpegthumbnailer command works, but nautilus failed to genereate thumbnails

In order to get a newer version of ffmpegthumbnailer that supports embedded image metadata. I manually compiled the (currrently) lastest release version 2.2.2 from github.

 -m : prefer embedded image metadata over video content

here are some information about my environment

➜ ~ nautilus --version
GNOME nautilus 3.26.4
➜ ~ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.4 LTS
Release: 18.04
Codename: bionic
➜ ~ uname -a
Linux Play-PC-VPC 5.0.0-25-generic #26~18.04.1-Ubuntu SMP Thu Aug 1 13:51:02 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
➜ ~ echo $0
zsh
➜ ~ g++ --version
g++ (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

here is what i did to compile/install it:

sudo apt install build-essential cmake pkg-config
sudo apt install libjpeg-dev libpng-dev zlib1g libavcodec-dev libavformat-dev libavfilter-dev
wget
tar -xvf ffmpegthumbnailer-2.2.2.tar.bz2
cd ffmpegthumbnailer-2.2.2
cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_GIO=ON -DENABLE_THUMBNAILER=ON .
make
sudo make install

and here is how I configure thumbnailer (sudo vim /usr/share/thumbnailers/ffmpegthumbnailer.thumbnailer)

[Thumbnailer Entry]
TryExec=ffmpegthumbnailer
Exec=ffmpegthumbnailer -i %i -o %o -s %s -f
MimeType=video/jpeg;video/mp4;video/mpeg;video/quicktime;video/x-ms-asf;video/x-ms-wm;video/x-ms-wmv;video/x-msvideo;video/x-flv;video/x-matroska;video/webm;video/mp2t;

Ps. please ignore the missing -m part, cause I haven't get it to show any thumbs yet.

also tried removing cache with following command

rm -r ~/.cache/thumbnails/

It looks like this.

Ps. again i don't have totem installed since it is a minimal install

here is another pic shows ffmpegthumbnailer does work

my nautilus preference:

Trobleshooting steps tried:

1. bwarp

during further search (couldn't remember what I was typing on the search box LOL) and copy & paste what it says

Ubuntu 18.04 - Solve Nautilus 3.26.4+ external thumbnailers problem

sudo wget -O /usr/local/bin/bwrap
sudo chmod +rx /usr/local/bin/bwrap
rm -r ~/.cache/thumbnails/
sudo reboot

not working, rm /usr/local/bin/bwrap...

oh, and playing with bwarp, I tried print out the command called:

/usr/bin/bwrap --ro-bind /usr/local/bin /usr/local/bin bind /home/play_pc/ff_log /home/play_pc/ff_log --ro-bind /etc/alternatives /etc/alternatives --ro-bind /etc/ImageMagick-6 /etc/ImageMagick-6 --ro-bind /var/cache/fontconfig /var/cache/fontconfig --ro-bind /usr /usr --ro-bind /bin /bin --ro-bind /lib64 /lib64 --ro-bind /lib /lib --ro-bind /sbin /sbin --proc /proc --dev /dev --chdir / --setenv GIO_USE_VFS local --unshare-all --die-with-parent --bind /tmp/gnome-desktop-thumbnailer-FL9UJ0 /tmp --ro-bind /home/play_pc/Downloads/wo_feature.mkv /tmp/gnome-desktop-file-to-thumbnail.mkv --seccomp 17 ffmpegthumbnailer -i /tmp/gnome-desktop-file-to-thumbnail.mkv -o /tmp/gnome-desktop-thumbnailer.png -s 256 -f

2. mv ffmpegthumbnailer

so... the bwarp thing got me thinking maybe it's the binding path that cause the problem, so I moved ffmpegthumbnailer execution file

➜ ~ which ffmpegthumbnailer
/usr/local/bin/ffmpegthumbnailer
➜ ~ sudo mv /usr/local/bin/ffmpegthumbnailer /usr/bin/ffmpegthumbnailer
➜ ~ which ffmpegthumbnailer
/usr/bin/ffmpegthumbnailer

and... it still doesn't work

3. check permission

➜ ~ ls -l /usr/local/bin
total 32
-rwxr-xr-x 1 root root 30576 May 4 20:46 ffmpegthumbnailer
➜ ~ sudo ls -l /usr/share/thumbnailers/
total 20
-rw-r--r-- 1 root root 803 Jun 19 2019 evince.thumbnailer
-rw-r--r-- 1 root root 259 May 4 20:52 ffmpegthumbnailer.thumbnailer
-rw-r--r-- 1 root root 525 Mar 16 2018 gdk-pixbuf-thumbnailer.thumbnailer
-rw-r--r-- 1 root root 213 Mar 13 2018 gnome-font-viewer.thumbnailer
-rw-r--r-- 1 root root 158 Dec 31 2017 librsvg.thumbnailer
➜ ~ sudo killall nautilus
nautilus: no process found
➜ ~ rm -r ~/.cache/thumbnails
➜ ~ mkdir ~/.cache/thumbnails
➜ ~ chown -R play_pc:play_pc ~/.cache/thumbnails
➜ ~ sudo reboot

4. use abs-path instead

[Thumbnailer Entry]
TryExec=/usr/local/bin/ffmpegthumbnailer
Exec=/usr/local/bin/ffmpegthumbnailer -i %i -o %o -s %s -f
MimeType=video/jpeg;video/mp4;video/mpeg;video/quicktime;video/x-ms-asf;video/x-ms-wm;video/x-ms-wmv;video/x-msvideo;video/x-flv;video/x-matroska;video/webm;video/mp2t;

At this point, I think I've honestly ran out of ideas. Can someone so kindly point me something I can try. plz

3 Answers

For some reason the shared libraries do not work in /usr/local/lib.
I could make the thumbnails show up by adding a few steps.
your last action is
sudo make install
continue with
sudo ldconfig
sudo mv /usr/local/lib/*ffmpegthumb* /usr/lib
Not quite sure if this is now a 'legal' location for these libraries.
I notice that the default library location is working on 16.04 and wonder what is the difference. Tested on 20.04, moving the libs is also needed there.

thumbnail viewer for myvideo :

Here is an overview of what I did (on 18.04) to generate thumbnails for a proprietary filetype, let's call it myvideo, subtype of video. It should contain what you need (last bullet). Assume the binary that generates the thumbnails is already built and is called gnome-thumbnail-myvideo.

installation:

• make a mimetype video/myvideo (myvideo as subtype of mediatype video)
  here is explained how to make this only for the current user
  mkdir ~/.local/share/mime/packages (if not existing yet)
  copy myvideo.xml to .local/share/mime/packages
  check if it is readable
  sudo update-mime-database ~/.local/share/mime/

• installing the icon for myvideo in file manager
  make sure the icon is readable for all :
  chmod +r video-myvideo.svg
  since myvideo is part of mediatype video, it should now already have the generic icon for this type
  check the icon theme by
  gsettings get org.gnome.desktop.interface gtk-theme
find /usr/share/icons | grep video-x-generic
  Then place a copy of the icon in a suitable format to all the locations in the relevant icon theme (e.g. Humanity) where you found video-x-generic ... Check if it is still readable by all (experienced that copying can change the rights). Update the icon caches:
  sudo update-icon-caches /usr/share/icons/*
sudo gtk-update-icon-cache /usr/share/icons/Humanity (or another one) Ready.

• copy program gnome-thumbnail-myvideo to /usr/local/bin (sudo)
  due to a problem with sandboxing for thumbnails (18.04 onwards), you cannot use the program in a local user folder
  check if it is executable once it is copied to /usr/local/bin
  check if it is readable
  place a thumbnailer file (e.g. myvideo.thumbnailer) in /usr/share/thumbnailers or /usr/local/share/thumbnailers
  close the file manager
  rm all *.png files under subfolders of ~/.cache/thumbnails
  restart file manager, it should work, or after logout/login

Not using Ubuntu, but a suggestion which could help.

I am actually using Xanmod kernel from AUR in Arch linux:

Linux version 5.8.6-xanmod1-1 (makepkg@archlinux) (gcc (GCC) 10.2.0, GNU ld (GNU Binutils) 2.35) #1 SMP PREEMPT Thu, 10 Sep 2020 00:51:21 +0000

During compilation I set the CONFIG_USER_NS_UNPRIVILEGED to n:

$ zcat /proc/config.gz | grep --color=auto CONFIG_USER_NS_UNPRIVILEGED
# CONFIG_USER_NS_UNPRIVILEGED is not set

As mentioned in the Archwiki

Note: On linux-hardened, thumbnails generation fails (all thumbnails go in ~/.cache/thumbnails/fail/). This is due to unprivileged user namespace being disabled by default on this kernel for security reasons. Nautilus uses bwrap (provided by bubblewrap) to sandbox thumbnailers. You may decide to replace bubblewrap with bubblewrap-suid.

That was my issue. Make sure you are not using Linux hardened or custom compiled kernel with CONFIG_USER_NS_UNPRIVILEGED unset.

This can be a little bit more hard to find so I shared my answer. I also launched bug report for this issue! Then I found out it was my fault.