QML Module not found (QtMultimedia)

[bob_harris]

I am getting this error while trying to use a Video QML type from QtMultimedia. I have tried everything I can think of.

I am using Qt 5.12, Qt Creator 4.9.0, C++ 17, and CMake 3.13

QML file

CMakeLists.txt

...

set(CMAKE_CXX_STANDARD 17)

set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
set(Qt5_DIR "/usr/local/opt/qt/lib/cmake/Qt5")

find_package(Qt5 COMPONENTS Core Quick Widgets Multimedia REQUIRED)

set(SRC_FILES main.cpp backend.h backend.cpp)
set(QML_FILES qml/BackButton.qml qml/DecodeView.qml qml/EncodeView.qml qml/FileLoader.qml main.qml qml/SubtitleView.qml qml/videoTranscription.qml)
set(RES_FILES qml.qrc resources/icon.icns resources/logo_transparent.png)

add_executable(${PROJECT_NAME} ${SRC_FILES} ${QML_FILES} ${RES_FILES})
target_compile_definitions(${PROJECT_NAME} PRIVATE $<$<OR:$<CONFIG:Debug>,$<CONFIG:RelWithDebInfo>>:QT_QML_DEBUG>)
target_link_libraries(${PROJECT_NAME} PRIVATE Qt5::Core Qt5::Quick Qt5::Widgets Qt5::Multimedia)

...

I tried to set the QML_IMPORT_PATH to the location of QtMultimedia but to no avail

QML_IMPORT_PATH

set(QML_IMPORT_PATH ${CMAKE_SOURCE_DIR}/qml ${CMAKE_BINARY_DIR}/imports /usr/local/opt/qt/lib/ CACHE STRING "" FORCE)

[J.Hilk]

Hi @bob_harris
and welcome.

I' ve little experience with cmake, so I can't give you a 100% straight answer. But I'm pretty sure what the issue is and how you could fix it. But if no-one else can help you more directly, it should point you in the correct direction.

QtMultimedia is it's own module. In qmake you would simply write QT += multimedia to link against it.
cmake has qt5_use_modules(target [LINK_PUBLIC|LINK_PRIVATE] module ... )
see here for more information
https://doc.qt.io/qt-5/cmake-manual.html#module-variables

[bob_harris]

That qt5_use_modules() is fairly confusing. It states the macro is obsolete and target_link_libraries should be used instead.

Regardless I managed to fix this, QtCreator was defaulting to a version of Qt that CMake wasn't using.

I changed this by manually adding the location of the Homebrew installed version of Qt to QtCreator.