No QtMultimedia backends found. Only QMediaDevices, QAudioDevice, QSoundEffect, QAudioSink, and QAudioSource are available.

[JoeCFD]

The main media backend, built on FFmpeg, ensures seamless cross-platform functionality, and is the default on all platforms
from https://doc.qt.io/qt-6/qtmultimedia-index.html

FFmpeg package needs to be installed.

[SGaist]

Hi,

One way to determine what goes wrong is to start your application with the QT_DEBUG_PLUGINS environment set to 1. It will dump everything that goes on with the plugins.

[Newtron]

It shows this error libavformat.so.58: cannot open shared object file: No such file or directory

[SGaist]

Do you have that library in your system ?

[Newtron]

It's a subpackage of old ffmpeg but in my system I'm using latest version of ffmpeg.

[SGaist]

Sorry to say that but: you did not answer the question. The library searched is libavformat version 58. Do you have that version available ? Based on the message, no, but it could be a path issue.

[friedemannkleint]

Can you please try the recent version (6.8.0.2)? There were some Multimedia libraries missing in some of the 6.7 versions.

[Big_bo]

@SGaist I have the same issue. The version of Qt I am using is 6.7.3.
qt.core.library: "/opt/Qt/6.7.3/gcc_arm64/plugins/imageformats/libqwebp.so" cannot load: Cannot load library /opt/Qt/6.7.3/gcc_arm64/plugins/imageformats/libqwebp.so: libwebp.so.6:cannot open
qt.core.plugin.loader: QLibraryPrivate::loadPlugin failed on "/opt/Qt/6.7.3/gcc_arm64/plugins/imageformats/libqwebp.so" : "Cannot load library /opt/Qt/6.7.3/gcc_arm64/plugins/imageformats/libqwebp.so: libwebp.so.6: cannot open

[JoeCFD]

@Big_bo ldd /opt/Qt/6.7.3/gcc_arm64/plugins/imageformats/libqwebp.so to see what is missing.

[Big_bo]

@JoeCFD
here is it

[Big_bo]

@JoeCFD When I execute the command:ldd /opt/Qt/6.7.3/gcc_arm64/plugins/imageformats/libqwebp.so

libwebp.so.6 => not found
libwebp.so.7 => /lib/aarch64-linux-gnu/libwebp.so.7 (0x0000007fa2330000)

I’m not quite sure what happened. Could you please help me? greatly appreciate it.

[Big_bo]

@JoeCFD
oh，I forgot to mention, I don't have this issue when using Qt5.

[JoeCFD]

@Big_bo libqwebp.so needs libwebp.so.6. Type command:
locate libwebp.so.6
to find its path. Then add its path to your env lib path