Full support for the H.264 video codec cannot be found

I have Fedora KDE Plasma installed, and everything is working, except that when I try to open some of my Windows videos with VLC or Dragon, they either play a black screen with only audio or display the following error message:

Full support for the H.264 video codec cannot be found. Video playback may be less reliable than expected.

Please contact the Fedora Linux developers to report this issue or to learn how to install the missing video codecs.

The package “openh264-2.6.0-2.fc43.x86_64” is already installed.

I also don’t have an H.264 export option in Kdenlive.

Operating System: Fedora Linux 43
KDE Plasma Version: 6.5.5
KDE Frameworks Version: 6.22.0
Qt Version: 6.10.1
Kernel Version: 6.18.9-200.fc43.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 8 x 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
RAM: 8 GB (7.5 GB usable)
Graphics Processor 1: Intel® Iris® Xe Graphics
Graphics Processor 2: NVIDIA GeForce MX350
Manufacturer: Acer
Product Name: Aspire A517-52G
System Version: V1.34

I would be very grateful for any help!
Best regards

Did you install the RPM Fusion repos first?:

Thanks, Gregory. No I did not, but I think I could accomplish it now but to no avail. Same error message, and no export option in Kdenlive.

In Fedora 43, KDE … uninstall everything and reinstall cleanly:

chatgpt:
Alright :+1: Fedora 43 KDE — we’re going to do a completely clean multimedia reinstallation now.
I’ll give you a safe step-by-step sequence.

:broom: :one: Remove everything old (Fedora codecs + leftovers)

sudo dnf remove ffmpeg-free ffmpeg ffmpeg-libs \
libavcodec-free libavformat-free libavutil-free \
libswscale-free libswresample-free libpostproc-free \
gstreamer1-libav

Then clean up:

sudo dnf autoremove

:counterclockwise_arrows_button: :two: Re-enable RPM Fusion (cleanly)
If it’s already enabled, it won’t hurt:

sudo dnf install \
https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-43.noarch.rpm \
https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-43.noarch.rpm

Then:

sudo dnf upgrade --refresh

:clapper_board: :three: Install full ffmpeg + KDE-relevant codecs

sudo dnf install ffmpeg ffmpeg-libs

Then install the multimedia group properly (Fedora 43 syntax!):

sudo dnf group install Multimedia --with-optional

If the group does not exist:

sudo dnf group install multimedia --with-optional

:puzzle_piece: :four: Important plugins for KDE / Dragon / VLC

sudo dnf install \
gstreamer1-libav \
gstreamer1-plugins-bad-freeworld \
gstreamer1-plugins-ugly

:magnifying_glass_tilted_right: :five: Check if H.264 is now active

ffmpeg -codecs | grep h264

You should see:

DEV.LS h264

and ideally libx264.

:bullseye: If VLC still complains
In VLC under:
Tools → Preferences → Input/Codecs
Try disabling hardware acceleration for testing.

:rocket: Important for KDE
After everything, please reboot once:

reboot

If the H.264 error still appears afterward, please send me:

dnf list installed | grep ffmpeg

Then we’ll immediately see if a Fedora “free” package is still interfering somewhere.



chatgpt fand die Lösung:

Alles klar :+1: Fedora 43 KDE — wir machen jetzt eine komplett saubere Multimedia-Neuinstallation.

Ich gebe dir eine sichere Schritt-für-Schritt-Reihenfolge.


:broom: :one: Alles Alte entfernen (Fedora-Codecs + Reste)

sudo dnf remove ffmpeg-free ffmpeg ffmpeg-libs \
libavcodec-free libavformat-free libavutil-free \
libswscale-free libswresample-free libpostproc-free \
gstreamer1-libav

Danach aufräumen:

sudo dnf autoremove

:counterclockwise_arrows_button: :two: RPM Fusion neu aktivieren (sauber)

Falls schon aktiv, schadet es nicht:

sudo dnf install \
https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-43.noarch.rpm \
https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-43.noarch.rpm

Dann:

sudo dnf upgrade --refresh

:clapper_board: :three: Vollständiges ffmpeg + KDE-relevante Codecs installieren

sudo dnf install ffmpeg ffmpeg-libs

Dann die Multimedia-Gruppe korrekt (Fedora 43 Syntax!):

sudo dnf group install Multimedia --with-optional

Falls die Gruppe nicht existiert:

sudo dnf group install multimedia --with-optional

:puzzle_piece: :four: KDE / Dragon / VLC wichtige Plugins

sudo dnf install \
gstreamer1-libav \
gstreamer1-plugins-bad-freeworld \
gstreamer1-plugins-ugly

:magnifying_glass_tilted_right: :five: Prüfen ob H.264 jetzt aktiv ist

ffmpeg -codecs | grep h264

Du solltest sehen:

DEV.LS h264

und idealerweise libx264.


:bullseye: Falls VLC noch meckert

In VLC unter:

Werkzeuge → Einstellungen → Eingabe/Codecs

Hardwarebeschleunigung ggf. testweise deaktivieren.

:rocket: Wichtig für KDE

Nach allem bitte einmal neu starten:

reboot

Wenn danach noch der H.264-Fehler kommt, schick mir bitte:

dnf list installed | grep ffmpeg

Dann sehen wir sofort, ob irgendwo noch ein Fedora-„free“ Paket dazwischenfunkt.

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