Some libraries that the gst-libav package relies on are missing.

[Tom Brossman]

Recently I tested several video players, and after uninstalling them I
can no longer view MP4 videos using Totem. I definitely have the necessary gstreamer plugins installed, however Totem incorrectly reports "Required plugin
could not be found". It is as if Totem can no longer detect my installed plugins.

I'm on Ubuntu 16.04.4 LTS running Totem 3.18.1-1ubuntu4

I first filed a bug for Totem here on Launchpad, which has more details: https://bugs.launchpad.net/ubuntu/+source/totem/+bug/1751578

Following the recommendation given in the bug report, I filed a bug for Totem at GNOME Bugzilla here: https://bugzilla.gnome.org/show_bug.cgi?id=793834.

The advice received is that "Some libraries that the gst-libav package relies on are missing.", so I'm filing the newest bug report here.

Output of gst-inspect-1.0 /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstlibav.so:

(gst-inspect-1.0:7455): GStreamer-WARNING **: Failed to load plugin '/usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstlibav.so': libsodium.so.18: cannot open shared object file: No such file or directory
Could not load plugin file: Opening module failed: libsodium.so.18: cannot open shared object file: No such file or directory

Output of ldd -r /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstlibav.so:

 linux-vdso.so.1 => (0x00007ffe2928e000)
 libavfilter-ffmpeg.so.5 => /usr/lib/x86_64-linux-gnu/libavfilter-ffmpeg.so.5 (0x00007fedf96f0000)
 libavformat-ffmpeg.so.56 => /usr/lib/x86_64-linux-gnu/libavformat-ffmpeg.so.56 (0x00007fedf92f2000)
 libavcodec-ffmpeg.so.56 => /usr/lib/x86_64-linux-gnu/libavcodec-ffmpeg.so.56 (0x00007fedf7ec3000)
 libavutil-ffmpeg.so.54 => /usr/lib/x86_64-linux-gnu/libavutil-ffmpeg.so.54 (0x00007fedf7c54000)
 libgstaudio-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstaudio-1.0.so.0 (0x00007fedf79f7000)
 libgstvideo-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstvideo-1.0.so.0 (0x00007fedf7771000)
 libgstpbutils-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstpbutils-1.0.so.0 (0x00007fedf753c000)
 libgstbase-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstbase-1.0.so.0 (0x00007fedf72d8000)
 libgstreamer-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstreamer-1.0.so.0 (0x00007fedf6fae000)
 libgobject-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 (0x00007fedf6d5b000)
 libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007fedf6a4a000)
 libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fedf682d000)
 libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fedf6463000)
 libswscale-ffmpeg.so.3 => /usr/lib/x86_64-linux-gnu/libswscale-ffmpeg.so.3 (0x00007fedf61d4000)
 libpostproc-ffmpeg.so.53 => /usr/lib/x86_64-linux-gnu/libpostproc-ffmpeg.so.53 (0x00007fedf5fb8000)
 libavresample-ffmpeg.so.2 => /usr/lib/x86_64-linux-gnu/libavresample-ffmpeg.so.2 (0x00007fedf5d96000)
 libswresample-ffmpeg.so.1 => /usr/lib/x86_64-linux-gnu/libswresample-ffmpeg.so.1 (0x00007fedf5b79000)
 libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fedf5975000)
 libzmq.so.5 => /usr/lib/x86_64-linux-gnu/libzmq.so.5 (0x00007fedf570f000)
 libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fedf5406000)
 libopencv_core.so.2.4 => /usr/lib/x86_64-linux-gnu/libopencv_core.so.2.4 (0x00007fedf4fdc000)
 libopencv_imgproc.so.2.4 => /usr/lib/x86_64-linux-gnu/libopencv_imgproc.so.2.4 (0x00007fedf4b51000)
 libfribidi.so.0 => /usr/lib/x86_64-linux-gnu/libfribidi.so.0 (0x00007fedf493a000)
 libfreetype.so.6 => /usr/lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007fedf4690000)
 libfontconfig.so.1 => /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007fedf444d000)
 libflite_cmu_us_awb.so.1 => /usr/lib/x86_64-linux-gnu/libflite_cmu_us_awb.so.1 (0x00007fedf3e58000)
 libflite_cmu_us_kal.so.1 => /usr/lib/x86_64-linux-gnu/libflite_cmu_us_kal.so.1 (0x00007fedf3af5000)
 libflite_cmu_us_kal16.so.1 => /usr/lib/x86_64-linux-gnu/libflite_cmu_us_kal16.so.1 (0x00007fedf351e000)
 libflite_cmu_us_rms.so.1 => /usr/lib/x86_64-linux-gnu/libflite_cmu_us_rms.so.1 (0x00007fedf2e86000)
 libflite_cmu_us_slt.so.1 => /usr/lib/x86_64-linux-gnu/libflite_cmu_us_slt.so.1 (0x00007fedf2890000)
 libflite.so.1 => /usr/lib/x86_64-linux-gnu/libflite.so.1 (0x00007fedf265a000)
 libbs2b.so.0 => /usr/lib/x86_64-linux-gnu/libbs2b.so.0 (0x00007fedf2454000)
 libass.so.5 => /usr/lib/x86_64-linux-gnu/libass.so.5 (0x00007fedf2224000)
 libssh-gcrypt.so.4 => /usr/lib/x86_64-linux-gnu/libssh-gcrypt.so.4 (0x00007fedf1fdb000)
 librtmp.so.1 => /usr/lib/x86_64-linux-gnu/librtmp.so.1 (0x00007fedf1dbf000)
 libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007fedf1ba5000)
 libmodplug.so.1 => /usr/lib/x86_64-linux-gnu/libmodplug.so.1 (0x00007fedf181a000)
 libgme.so.0 => /usr/lib/x86_64-linux-gnu/libgme.so.0 (0x00007fedf15cc000)
 libbluray.so.1 => /usr/lib/x86_64-linux-gnu/libbluray.so.1 (0x00007fedf1383000)
 libgnutls.so.30 => /usr/lib/x86_64-linux-gnu/libgnutls.so.30 (0x00007fedf1053000)
 libbz2.so.1.0 => /lib/x86_64-linux-gnu/libbz2.so.1.0 (0x00007fedf0e43000)
 libva.so.1 => /usr/lib/x86_64-linux-gnu/libva.so.1 (0x00007fedf0c27000)
 libzvbi.so.0 => /usr/lib/x86_64-linux-gnu/libzvbi.so.0 (0x00007fedf099c000)
 libxvidcore.so.4 => /usr/lib/x86_64-linux-gnu/libxvidcore.so.4 (0x00007fedf0688000)
 libx265.so.79 => /usr/lib/x86_64-linux-gnu/libx265.so.79 (0x00007fedefa69000)
 libx264.so.148 => /usr/lib/x86_64-linux-gnu/libx264.so.148 (0x00007fedef6c5000)
 libwebp.so.5 => /usr/lib/x86_64-linux-gnu/libwebp.so.5 (0x00007fedef469000)
 libwavpack.so.1 => /usr/lib/x86_64-linux-gnu/libwavpack.so.1 (0x00007fedef240000)
 libvpx.so.3 => /usr/lib/x86_64-linux-gnu/libvpx.so.3 (0x00007fedeee1c000)
 libvorbisenc.so.2 => /usr/lib/x86_64-linux-gnu/libvorbisenc.so.2 (0x00007fedeeb73000)
 libvorbis.so.0 => /usr/lib/x86_64-linux-gnu/libvorbis.so.0 (0x00007fedee947000)
 libvo-amrwbenc.so.0 => /usr/lib/x86_64-linux-gnu/libvo-amrwbenc.so.0 (0x00007fedee72d000)
 libvo-aacenc.so.0 => /usr/lib/x86_64-linux-gnu/libvo-aacenc.so.0 (0x00007fedee510000)
 libtwolame.so.0 => /usr/lib/x86_64-linux-gnu/libtwolame.so.0 (0x00007fedee2ed000)
 libtheoraenc.so.1 => /usr/lib/x86_64-linux-gnu/libtheoraenc.so.1 (0x00007fedee0ae000)
 libtheoradec.so.1 => /usr/lib/x86_64-linux-gnu/libtheoradec.so.1 (0x00007fedede94000)
 libspeex.so.1 => /usr/lib/x86_64-linux-gnu/libspeex.so.1 (0x00007fededc7b000)
 libsnappy.so.1 => /usr/lib/x86_64-linux-gnu/libsnappy.so.1 (0x00007fededa73000)
 libshine.so.3 => /usr/lib/x86_64-linux-gnu/libshine.so.3 (0x00007feded866000)
 libschroedinger-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libschroedinger-1.0.so.0 (0x00007feded591000)
 libopus.so.0 => /usr/lib/x86_64-linux-gnu/libopus.so.0 (0x00007feded347000)
 libopenjpeg.so.5 => /usr/lib/x86_64-linux-gnu/libopenjpeg.so.5 (0x00007feded124000)
 libopencore-amrwb.so.0 => /usr/lib/x86_64-linux-gnu/libopencore-amrwb.so.0 (0x00007fedecf10000)
 libopencore-amrnb.so.0 => /usr/lib/x86_64-linux-gnu/libopencore-amrnb.so.0 (0x00007fedecce5000)
 libmp3lame.so.0 => /usr/lib/x86_64-linux-gnu/libmp3lame.so.0 (0x00007fedeca70000)
 libgsm.so.1 => /usr/lib/x86_64-linux-gnu/libgsm.so.1 (0x00007fedec862000)
 libcrystalhd.so.3 => /usr/lib/x86_64-linux-gnu/libcrystalhd.so.3 (0x00007fedec647000)
 liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007fedec425000)
 libgsttag-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgsttag-1.0.so.0 (0x00007fedec1ea000)
 liborc-0.4.so.0 => /usr/lib/x86_64-linux-gnu/liborc-0.4.so.0 (0x00007fedebf6a000)
 libgmodule-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgmodule-2.0.so.0 (0x00007fedebd66000)
 librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fedebb5e000)
 libffi.so.6 => /usr/lib/x86_64-linux-gnu/libffi.so.6 (0x00007fedeb956000)
 libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007fedeb6e6000)
 /lib64/ld-linux-x86-64.so.2 (0x00007fedf9cd0000)
 libsoxr.so.0 => /usr/lib/x86_64-linux-gnu/libsoxr.so.0 (0x00007fedeb481000)
 libsodium.so.18 => not found
 libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fedeb0ff000)
 libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fedeaee9000)
 libGL.so.1 => /usr/lib/x86_64-linux-gnu/mesa/libGL.so.1 (0x00007fedeac76000)
 libtbb.so.2 => /usr/lib/x86_64-linux-gnu/libtbb.so.2 (0x00007fedeaa39000)
 libpng12.so.0 => /lib/x86_64-linux-gnu/libpng12.so.0 (0x00007fedea814000)
 libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007fedea5eb000)
 libflite_usenglish.so.1 => /usr/lib/x86_64-linux-gnu/libflite_usenglish.so.1 (0x00007fedea3c2000)
 libflite_cmulex.so.1 => /usr/lib/x86_64-linux-gnu/libflite_cmulex.so.1 (0x00007fedea12d000)
 libasound.so.2 => /usr/lib/x86_64-linux-gnu/libasound.so.2 (0x00007fede9e2d000)
 libharfbuzz.so.0 => /usr/lib/x86_64-linux-gnu/libharfbuzz.so.0 (0x00007fede9bcf000)
 libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007fede98ee000)
 libgssapi_krb5.so.2 => /usr/lib/x86_64-linux-gnu/libgssapi_krb5.so.2 (0x00007fede96a4000)
 libhogweed.so.4 => /usr/lib/x86_64-linux-gnu/libhogweed.so.4 (0x00007fede9471000)
 libnettle.so.6 => /usr/lib/x86_64-linux-gnu/libnettle.so.6 (0x00007fede923b000)
 libgmp.so.10 => /usr/lib/x86_64-linux-gnu/libgmp.so.10 (0x00007fede8fbb000)
 libxml2.so.2 => /usr/lib/x86_64-linux-gnu/libxml2.so.2 (0x00007fede8c00000)
 libp11-kit.so.0 => /usr/lib/x86_64-linux-gnu/libp11-kit.so.0 (0x00007fede899c000)
 libidn.so.11 => /usr/lib/x86_64-linux-gnu/libidn.so.11 (0x00007fede8769000)
 libtasn1.so.6 => /usr/lib/x86_64-linux-gnu/libtasn1.so.6 (0x00007fede8556000)
 libnuma.so.1 => /usr/lib/x86_64-linux-gnu/libnuma.so.1 (0x00007fede834b000)
 libogg.so.0 => /usr/lib/x86_64-linux-gnu/libogg.so.0 (0x00007fede8142000)
 libgomp.so.1 => /usr/lib/x86_64-linux-gnu/libgomp.so.1 (0x00007fede7f20000)
 libxcb-dri3.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-dri3.so.0 (0x00007fede7d1d000)
 libxcb-present.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-present.so.0 (0x00007fede7b1a000)
 libxcb-sync.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007fede7913000)
 libxshmfence.so.1 => /usr/lib/x86_64-linux-gnu/libxshmfence.so.1 (0x00007fede7710000)
 libglapi.so.0 => /usr/lib/x86_64-linux-gnu/libglapi.so.0 (0x00007fede74e0000)
 libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007fede72ce000)
 libXdamage.so.1 => /usr/lib/x86_64-linux-gnu/libXdamage.so.1 (0x00007fede70cb000)
 libXfixes.so.3 => /usr/lib/x86_64-linux-gnu/libXfixes.so.3 (0x00007fede6ec5000)
 libX11-xcb.so.1 => /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007fede6cc3000)
 libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007fede6989000)
 libxcb-glx.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-glx.so.0 (0x00007fede6770000)
 libxcb-dri2.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-dri2.so.0 (0x00007fede656b000)
 libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007fede6349000)
 libXxf86vm.so.1 => /usr/lib/x86_64-linux-gnu/libXxf86vm.so.1 (0x00007fede6143000)
 libdrm.so.2 => /usr/lib/x86_64-linux-gnu/libdrm.so.2 (0x00007fede5f32000)
 libgraphite2.so.3 => /usr/lib/x86_64-linux-gnu/libgraphite2.so.3 (0x00007fede5d0c000)
 libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007fede5af8000)
 libkrb5.so.3 => /usr/lib/x86_64-linux-gnu/libkrb5.so.3 (0x00007fede5826000)
 libk5crypto.so.3 => /usr/lib/x86_64-linux-gnu/libk5crypto.so.3 (0x00007fede55f7000)
 libcom_err.so.2 => /lib/x86_64-linux-gnu/libcom_err.so.2 (0x00007fede53f3000)
 libkrb5support.so.0 => /usr/lib/x86_64-linux-gnu/libkrb5support.so.0 (0x00007fede51e8000)
 libicuuc.so.55 => /usr/lib/x86_64-linux-gnu/libicuuc.so.55 (0x00007fede4e54000)
 libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007fede4c50000)
 libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007fede4a4a000)
 libkeyutils.so.1 => /lib/x86_64-linux-gnu/libkeyutils.so.1 (0x00007fede4846000)
 libresolv.so.2 => /lib/x86_64-linux-gnu/libresolv.so.2 (0x00007fede462b000)
 libicudata.so.55 => /usr/lib/x86_64-linux-gnu/libicudata.so.55 (0x00007fede2b74000)
undefined symbol: randombytes_close (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: crypto_box_open_afternm (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: crypto_secretbox_open (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: randombytes (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: crypto_box_keypair (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: crypto_box_afternm (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: crypto_box_open (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: crypto_box (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: sodium_init (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: crypto_secretbox (/usr/lib/x86_64-linux-gnu/libzmq.so.5)
undefined symbol: crypto_box_beforenm (/usr/lib/x86_64-linux-gnu/libzmq.so.5)

[Daniel van Vugt (vanvugt)]

Thanks for the bug report.

Although given this started with you removing packages, this might not be a bug. It depends on whether your system thinks its packages are fully installed and clean still.

Please run these commands to try and clean up the packages state:

  sudo apt update
  sudo apt -f full-upgrade

Do those commands return any errors? Does it work after you reboot?

[Daniel van Vugt (vanvugt)]

Possibly also related is bug 1576479

[Tom Brossman (tom.brossman)]

apt update && apt -f full-upgrade ran like usual and returned "0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade." After a reboot nothing changed, I still can't play MP4 video.

Is there a way to clear everything out and start over? I looked into this yesterday but cancelled when I saw the ubuntu-desktop package was going to be removed (I think the command I tried was "apt-get purge gstreamer1.0*" or similar).

Thanks again for the troubleshooting help and if there's anything else I can test please let me know. I would like to understand how I can avoid this happening again, or recover from it on my own if it does.

[dino99 (9d9)]

Suggestion: try to read a mp4 video from the terminal, to grab possible output error

[Sebastien Bacher (seb128)]

What's the output of those commands on your system?

- dpkg -l | grep libav
- dpkg -l | grep libsodium
- debsums libsodium18

[Daniel van Vugt (vanvugt)]

Tom,

I think the package you are missing is: libsodium18

Try this:

  sudo apt install libsodium18

[Tom Brossman (tom.brossman)]

> Suggestion: try to read a mp4 video from the terminal, to grab possible output error

tom@desktop:~$ totem Desktop/VIDEO.mp4
** Message: Missing plugin: gstreamer|1.0|totem|H.264 (Main Profile) decoder|decoder-video/x-h264, level=(string)3.1, profile=(string)main, max-input-size=(int)64271 (H.264 (Main Profile) decoder)
/usr/lib/python3/dist-packages/sessioninstaller/core.py:47: PyGIWarning: Gst was imported without specifying a version first. Use gi.require_version('Gst', '1.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gst
/usr/lib/python3/dist-packages/sessioninstaller/core.py:48: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gtk
Falling back to package information
CRITICAL:Could not find any packages to operate on
** Message: No installation candidate for missing plugins found.

> dpkg -l | grep libav

gstreamer1.0-libav:amd64 1.8.3-1ubuntu0.2
libavahi-client3:amd64 0.6.32~rc+dfsg-1ubuntu2
libavahi-common-data:amd64 0.6.32~rc+dfsg-1ubuntu2
libavahi-common3:amd64 0.6.32~rc+dfsg-1ubuntu2
libavahi-core7:amd64 0.6.32~rc+dfsg-1ubuntu2
libavahi-glib1:amd64 0.6.32~rc+dfsg-1ubuntu2
libavahi-ui-gtk3-0:amd64 0.6.32~rc+dfsg-1ubuntu2
libavc1394-0:amd64 0.5.4-4
libavcodec-ffmpeg-extra56:amd64 7:2.8.11-0ubuntu0.16.04.1
libavdevice-ffmpeg56:amd64 7:2.8.11-0ubuntu0.16.04.1
libavfilter-ffmpeg5:amd64 7:2.8.11-0ubuntu0.16.04.1
libavformat-ffmpeg56:amd64 7:2.8.11-0ubuntu0.16.04.1
libavresample-ffmpeg2:amd64 7:2.8.11-0ubuntu0.16.04.1
libavutil-ffmpeg54:amd64 7:2.8.11-0ubuntu0.16.04.1

> dpkg -l | grep libsodium

libsodium18:amd64 1.0.16-0ppa1~xenial1

> debsums libsodium18

/usr/lib/x86_64-linux-gnu/libsodium.so.23.1.0 OK
/usr/share/doc/libsodium18/changelog.Debian.gz OK
/usr/share/doc/libsodium18/copyright OK

> sudo apt install libsodium18

Reading package lists... Done
Building dependency tree
Reading state information... Done
libsodium18 is already the newest version (1.0.16-0ppa1~xenial1).
0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.

[Daniel van Vugt (vanvugt)]

The correct version of libsodium18 on xenial is 1.0.8-5

Please purge your PPAs, which sound like the cause of the problem...

sudo apt install ppa-purge
ppa-purge ...

[Sebastien Bacher (seb128)]

right, the issue is

"libsodium18:amd64 1.0.16-0ppa1~xenial1

> debsums libsodium18

/usr/lib/x86_64-linux-gnu/libsodium.so.23.1.0 OK"

the package name is supposed to match the soname version, so .23 should be libsodium23 and not libsodium18, the ppa you are using is buggy

[Sebastien Bacher (seb128)]

closing as invalid, not a bug in an Ubuntu package

[Tom Brossman (tom.brossman)]

OK, mystery solved and thanks for the info about libsodium.

I no longer have any audiovisual PPAs I'm using, and I have no clue how to revert to the correct libsodium18 packages. Any suggestions? I did use ppa-purge when switching back to the default player, but this hasn't worked out as intended.

[Sebastien Bacher (seb128)]

"sudo apt-get install libsodium18/xenial" sound do the trick

[Daniel van Vugt (vanvugt)]

... if not then also try:

sudo apt-get install --reinstall libsodium18/xenial

[Tom Brossman (tom.brossman)]

> apt-get install --reinstall libsodium18/xenial

This did downgrade the libsodium package, but I still can't play MP4 videos.

I've gone through my bash history and redone all the previous steps of adding packages, PPAs, using ppa-purge, and updating. I wanted to make sure I was doing things properly and in the correct order and after trying that nothing is fixed, same issue:

tom@desktop:~$ totem Desktop/video.mp4
** Message: Missing plugin: gstreamer|1.0|totem|H.264 (Main Profile) decoder|decoder-video/x-h264, level=(string)3.1, profile=(string)main, max-input-size=(int)319716 (H.264 (Main Profile) decoder)
/usr/lib/python3/dist-packages/sessioninstaller/core.py:47: PyGIWarning: Gst was imported without specifying a version first. Use gi.require_version('Gst', '1.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gst
/usr/lib/python3/dist-packages/sessioninstaller/core.py:48: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gtk
Falling back to package information
CRITICAL:Could not find any packages to operate on
** Message: No installation candidate for missing plugins found.

At this point I've spent more time troubleshooting than a complete reinstall of Ubuntu would have taken, so I have to cut my losses and try that. Thanks for the help and tips, I did learn quite a bit about troubleshooting.

[Daniel van Vugt (vanvugt)]

I'm not sure how much of that is related. I get some of the same messages on a working xenial machine:

$ gst-install --help
/usr/lib/python3/dist-packages/sessioninstaller/core.py:47: PyGIWarning: Gst was imported without specifying a version first. Use gi.require_version('Gst', '1.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gst
/usr/lib/python3/dist-packages/sessioninstaller/core.py:48: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gtk
Falling back to package information
usage: gst-install [-h] [--transient-for XID] [--interaction INTERACTION]
                   [--desktop-id DESKTOP_ID]
                   [--startup-notification-id STARTUP_NOTIFICATION_ID]
                   codec [codec ...]

[Daniel van Vugt (vanvugt)]

You may want to do a general check for possible PPA-related packages still installed:

dpkg -l | grep ppa

[Tom Brossman (tom.brossman)]

Apologies for the extra notification, but the command:

rm -rf ~/.cache/gstreamer-1.0/

instantly resolved my issue. In that directory was a file "registry.x86_64.bin" and after deleting it everything works perfectly as before. Totem, gnome-sushi previews, everything.

The libsodium / PPA issue I had was probably related to this bug, but none of the workarounds posted there resolved video playback issues (nor did removing all PPAs and their related packages): https://github.com/keepassxreboot/keepassxc/issues/1545#issuecomment-369163954