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

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  • N Offline
    N Offline
    Newtron
    wrote on 8 Nov 2024, 12:10 last edited by
    #1

    I am working on a project on Asahi Linux on Macbook air m1 and tried Camera class in qml file.
    Tried to load qml in pyside 6 using qqmlapplicationengine

    .........
    CaptureSession {
                camera: Camera {
                    id: camera
    
                    focusMode: Camera.FocusModeAutoNear
                    customFocusPoint: Qt.point(0.2, 0.2) // Focus relative to top-left corner
                }
                videoOutput: videoOutput
            }
    
            VideoOutput {
                id: videoOutput
                anchors.fill: parent
            }
        }
    .......
    

    It shows the following error:

    No QtMultimedia backends found. Only QMediaDevices, QAudioDevice, QSoundEffect, QAudioSink, and QAudioSource are available.
    Failed to initialize QMediaCaptureSession "Not available"
    Failed to initialize QCamera "Not available"
    Failed to create QVideoSink "Not available"
    

    By I've seen similar posts talking about the same issue but not in asahi linux. From those articles I tried to downgrade pyside6 to a lower version(6.7.0 from 6.8) but it didn't work.

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    • J Offline
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      JoeCFD
      wrote on 8 Nov 2024, 16:56 last edited by
      #2

      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.

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      0
      • S Offline
        S Offline
        SGaist
        Lifetime Qt Champion
        wrote on 8 Nov 2024, 18:42 last edited by
        #3

        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.

        Interested in AI ? www.idiap.ch
        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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        • N Offline
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          Newtron
          wrote on 9 Nov 2024, 06:23 last edited by
          #4

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

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          • S Offline
            S Offline
            SGaist
            Lifetime Qt Champion
            wrote on 9 Nov 2024, 20:00 last edited by
            #5

            Do you have that library in your system ?

            Interested in AI ? www.idiap.ch
            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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            • N Offline
              N Offline
              Newtron
              wrote on 10 Nov 2024, 09:09 last edited by
              #6

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

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              • S Offline
                S Offline
                SGaist
                Lifetime Qt Champion
                wrote on 10 Nov 2024, 09:28 last edited by
                #7

                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.

                Interested in AI ? www.idiap.ch
                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                • F Offline
                  F Offline
                  friedemannkleint
                  wrote on 10 Nov 2024, 11:01 last edited by
                  #8

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

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                  • B Offline
                    B Offline
                    Big_bo
                    wrote on 26 Nov 2024, 11:05 last edited by
                    #9

                    @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

                    J 1 Reply Last reply 26 Nov 2024, 11:57
                    0
                    • B Big_bo
                      26 Nov 2024, 11:05

                      @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

                      J Offline
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                      JoeCFD
                      wrote on 26 Nov 2024, 11:57 last edited by JoeCFD
                      #10

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

                      B 3 Replies Last reply 27 Nov 2024, 01:13
                      0
                      • J JoeCFD
                        26 Nov 2024, 11:57

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

                        B Offline
                        B Offline
                        Big_bo
                        wrote on 27 Nov 2024, 01:13 last edited by
                        #11

                        @JoeCFD 76819efc-94de-493c-b405-6cfdd582fe9d-图片.png
                        here is it

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                        • J JoeCFD
                          26 Nov 2024, 11:57

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

                          B Offline
                          B Offline
                          Big_bo
                          wrote on 27 Nov 2024, 01:25 last edited by
                          #12

                          @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.

                          J 1 Reply Last reply 27 Nov 2024, 19:51
                          0
                          • J JoeCFD
                            26 Nov 2024, 11:57

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

                            B Offline
                            B Offline
                            Big_bo
                            wrote on 27 Nov 2024, 03:07 last edited by
                            #13

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

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                            • B Big_bo
                              27 Nov 2024, 01:25

                              @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.

                              J Offline
                              J Offline
                              JoeCFD
                              wrote on 27 Nov 2024, 19:51 last edited by
                              #14

                              @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

                              1 Reply Last reply
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