我全新安装了 Ubuntu 20.04，并在安装时选择安装非免费编解码器。但显然我仍然缺少一些编解码器。当我想在 Handbrake 中预览文件时，我收到以下两个错误：
当我想在 Totem 中播放视频时出现此错误：
但它在 Ubuntu 软件中找不到任何东西，视频确实播放了。在 VLC 中我没有收到任何错误。
这是已安装的插件列表gstreamer。
dpkg -l | grep gstreamer
ii gir1.2-gstreamer-1.0:amd64 1.16.2-2 amd64 GObject introspection data for the GStreamer library
ii gstreamer1.0-alsa:amd64 1.16.2-4 amd64 GStreamer plugin for ALSA
ii gstreamer1.0-clutter-3.0:amd64 3.0.27-1 amd64 Clutter PLugin for GStreamer 1.0
ii gstreamer1.0-gl:amd64 1.16.2-4 amd64 GStreamer plugins for GL
ii gstreamer1.0-gtk3:amd64 1.16.2-1ubuntu2 amd64 GStreamer plugin for GTK+3
ii gstreamer1.0-libav:amd64 1.16.2-2 amd64 ffmpeg plugin for GStreamer
ii gstreamer1.0-packagekit 1.1.13-2ubuntu1 amd64 GStreamer plugin to install codecs using PackageKit
ii gstreamer1.0-plugins-base:amd64 1.16.2-4 amd64 GStreamer plugins from the "base" set
ii gstreamer1.0-plugins-base-apps 1.16.2-4 amd64 GStreamer helper programs from the "base" set
ii gstreamer1.0-plugins-good:amd64 1.16.2-1ubuntu2 amd64 GStreamer plugins from the "good" set
ii gstreamer1.0-plugins-ugly:amd64 1.16.2-2build1 amd64 GStreamer plugins from the "ugly" set
ii gstreamer1.0-pulseaudio:amd64 1.16.2-1ubuntu2 amd64 GStreamer plugin for PulseAudio
ii gstreamer1.0-tools 1.16.2-2 amd64 Tools for use with GStreamer
ii gstreamer1.0-vaapi:amd64 1.16.2-2 amd64 VA-API plugins for GStreamer
ii gstreamer1.0-x:amd64 1.16.2-4 amd64 GStreamer plugins for X11 and Pango
ii libgstreamer-gl1.0-0:amd64 1.16.2-4 amd64 GStreamer GL libraries
ii libgstreamer-plugins-bad1.0-0:amd64 1.16.2-2.1ubuntu1 amd64 GStreamer libraries from the "bad" set
ii libgstreamer-plugins-base1.0-0:amd64 1.16.2-4 amd64 GStreamer libraries from the "base" set
ii libgstreamer-plugins-good1.0-0:amd64 1.16.2-1ubuntu2 amd64 GStreamer development files for libraries from the "good" set
ii libgstreamer1.0-0:amd64 1.16.2-2 amd64 Core GStreamer libraries and elements
ii libqt5gstreamer-1.0-0:amd64 1.2.0-5 amd64 C++ bindings library for GStreamer with a Qt-style API - Qt 5 build