Correct way to install accelerated gstreamer rather than the plain version

I’m quite new to gstreamer. I tried to install the accelerated GStreamer following the Accelerated GStreamer User Guide.
Then I tried to verify the accelerated version was installed rather than the plain version by running

gst-launch-1.0 videotestsrc ! qtdemux ! queue ! h264parse ! nvv4l2decoder ! nv3dsink -e

But it returns:

WARNING: erroneous pipeline: no element "nvv4l2decoder"

This look like I did not get the accelerated version installed since the accelerated version contains the nvv4l2decoder.

What’s the right way to install the accelerated GStreamer? Also, is there .deb packages for the accelerated version? Any help would be appreciated.

Operating system: Ubuntu 18.04.4 LTS
Architecture: arm64

If not installed, you would just use:

sudo apt update
sudo apt install nvidia-l4t-gstreamer

Thanks for the info. I tried it out but after entering sudo apt install nvidia-l4t-gstreamerr it returns

E: Unable to locate package nvidia-l4t-gstreamer

Here’s what it returns after entering sudo apt update :

Hit:1 http://ports.ubuntu.com/ubuntu-ports bionic InRelease
Get:2 http://ports.ubuntu.com/ubuntu-ports bionic-updates InRelease [88.7 kB]
Get:3 http://ports.ubuntu.com/ubuntu-ports bionic-backports InRelease [74.6 kB]
Get:4 http://ports.ubuntu.com/ubuntu-ports bionic-security InRelease [88.7 kB]
Get:5 http://ports.ubuntu.com/ubuntu-ports bionic-security/main arm64 Packages [1,327 kB]
Get:6 http://ports.ubuntu.com/ubuntu-ports bionic-security/universe arm64 Packages [1,096 kB]
Fetched 2,675 kB in 4s (754 kB/s)                          
Reading package lists... Done
Building dependency tree       
Reading state information... Done
216 packages can be upgraded. Run 'apt list --upgradable' to see them.

Is there anything else that should be done beside the two commands?

What gives ?

head -n 1 /etc/nv_tegra_release

cat /etc/apt/sources.list.d/nvidia-l4t-apt-source.list

For head -n 1 /etc/nv_tegra_release, it gives

# R32 (release), REVISION: 4.3, GCID: 21589087, BOARD: t186ref, EABI: aarch64, DATE: Fri Jun 26 04:34:27 UTC 2020

And for cat /etc/apt/sources.list.d/nvidia-l4t-apt-source.list , it gives

cat: /etc/apt/sources.list.d/nvidia-l4t-apt-source.list: No such file or directory

I want to provide more context of what I did to install the accelerated gstreamer.

Basically according to the user guide, I just entered the following commands:

sudo apt-get update
sudo apt-get install gstreamer1.0-tools gstreamer1.0-alsa \
gstreamer1.0-plugins-base gstreamer1.0-plugins-good \ gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly \ gstreamer1.0-libav
sudo apt-get install libgstreamer1.0-dev \ libgstreamer-plugins-base1.0-dev \ libgstreamer-plugins-good1.0-dev \ libgstreamer-plugins-bad1.0-devsudo add-apt-repository universe
sudo add-apt-repository multiverse
sudo apt-get update
sudo apt-get install gstreamer1.0-tools gstreamer1.0-alsa \
gstreamer1.0-plugins-base gstreamer1.0-plugins-good \ gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly \ gstreamer1.0-libav
sudo apt-get install libgstreamer1.0-dev \ libgstreamer-plugins-base1.0-dev \ libgstreamer-plugins-good1.0-dev \ libgstreamer-plugins-bad1.0-dev

And here’s what my /etc/apt/sources.list looks like:

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-backports main restricted universe multiverse
# deb-src http://ports.ubuntu.com/ubuntu-ports/ bionic-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu bionic partner
# deb-src http://archive.canonical.com/ubuntu bionic partner

deb http://ports.ubuntu.com/ubuntu-ports/ bionic-security main restricted
# deb-src http://ports.ubuntu.com/ubuntu-ports/ bionic-security main restricted
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-security universe
# deb-src http://ports.ubuntu.com/ubuntu-ports/ bionic-security universe
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-security multiverse
# deb-src http://ports.ubuntu.com/ubuntu-ports/ bionic-security multiverse

R32.4.3 is already a quite old release. For this release, there may not be an apt package nvidia-l4t-gstreamer. The nvidia accelerated gstreamer plugins should be installed by jetpack, so there should be nothing more to do. If gstreamer cannot find these, probably there is something wrong in your environment.
I’d suggest reflashing, and better use latest release.