How to use GStreamer to play an mp4 video?

I want to use GStreamer on ubuntu 21.04. Here is what I have attempted:

user@host:~$ gst-launch-1.0 -v playbin uri=file:///home/user/thisVideo.mp4
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: ring-buffer-max-size = 0
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: buffer-size = -1
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: buffer-duration = -1
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: use-buffering = false
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: download = false
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: uri = file:///home/user/thisVideo.mp4
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: connection-speed = 0
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: source = "\(GstFileSrc\)\ source"
/GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = video/quicktime, variant=(string)iso
Missing element: Quicktime demuxer
WARNING: from element /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: No decoder available for type 'video/quicktime, variant=(string)iso'.
Additional debug info:
gsturidecodebin.c(921): unknown_type_cb (): /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0
ERROR: from element /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0: Your GStreamer installation is missing a plug-in.
Additional debug info:
gsturidecodebin.c(988): no_more_pads_full (): /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0:
no suitable plugins found:
gstdecodebin2.c(4640): gst_decode_bin_expose (): /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0/GstDecodeBin:decodebin0:
no suitable plugins found:
Missing decoder: Quicktime (video/quicktime, variant=(string)iso)

ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
Freeing pipeline ...

I think what this output implies is that the Quicktime demuxer is not installed on my system. Can somebody please tell me what I must do in order to play this video in GStreamer?

EDIT: It occurs to me that the problem is much deeper than just a missing decoder. Instead, it seems that I am missing all decoders. I have tried to apply GStreamer to various files of diverse formats, but I consistently receive messages of to the effect of 'missing decoder'. Here is yet another example:

user@host:~$ gst-play-1.0 /home/user/someAudio.flac
Press 'k' to see a list of keyboard shortcuts.
Now playing /home/user/someAudio.flac
WARNING No decoder available for type 'audio/x-flac'.
WARNING debug information: gsturidecodebin.c(921): unknown_type_cb (): /GstPlayBin:playbin/GstURIDecodeBin:uridecodebin0
ERROR Your GStreamer installation is missing a plug-in. for file:///home/user/someAudio.flac
ERROR debug information: gsturidecodebin.c(988): no_more_pads_full (): /GstPlayBin:playbin/GstURIDecodeBin:uridecodebin0:
no suitable plugins found:
gstdecodebin2.c(4640): gst_decode_bin_expose (): /GstPlayBin:playbin/GstURIDecodeBin:uridecodebin0/GstDecodeBin:decodebin0:
no suitable plugins found:
Missing decoder: Free Lossless Audio Codec (FLAC) (audio/x-flac)

Reached end of play list.

So I think the problem will be solved when I make all common decoders available to my system. But how to do it?

sudo apt install gstreamer1.0-plugins-base

And if it doesn't solve the problem

sudo apt install gstreamer1.0-plugins-good
sudo apt install gstreamer1.0-plugins-bad
sudo apt install gstreamer1.0-plugins-ugly