This is just a VLC backend for phonon, not the phonon itself. Currently this package is used only by dragon and none other, which does not have a qt5 version packaged yet.

On 23 October 2024 8:09:04 pm IST, Zheng Junjie <zhengjunjie@iscas.ac.cn> wrote:
>Sughosha via Guix-patches via <guix-patches@gnu.org> writes:
>
>> * gnu/packages/kde-frameworks.scm (phonon-backend-vlc): Switch to Qt6.
>> [arguments]<configure-flags>: Add "-DPHONON_BUILD_QT5=0" and replace
>> "-DPHONON_BUILD_QT6=OFF" with "-DPHONON_BUILD_QT6=1".
>> [native-inputs]: Replace qttools-5 with qttools.
>> [inputs]: Replace qtbase-5 with qtbase.
>>
>> Change-Id: I45380ca844e987bb27ee67106e35cb60fc0565c3
>> ---
>>  gnu/packages/kde-frameworks.scm | 7 ++++---
>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/gnu/packages/kde-frameworks.scm b/gnu/packages/kde-frameworks.scm
>> index 13d4e24726..a14ba1ffb0 100644
>> --- a/gnu/packages/kde-frameworks.scm
>> +++ b/gnu/packages/kde-frameworks.scm
>> @@ -311,11 +311,12 @@ (define-public phonon-backend-vlc
>>      (build-system cmake-build-system)
>>      (arguments
>>       (list #:configure-flags
>> -           #~(list "-DPHONON_BUILD_QT6=OFF")))
>> +           #~(list "-DPHONON_BUILD_QT5=0"
>> +                    "-DPHONON_BUILD_QT6=1")))
>>      (native-inputs
>> -     (list extra-cmake-modules qttools-5))
>> +     (list extra-cmake-modules qttools))
>>      (inputs
>> -     (list phonon qtbase-5 vlc))
>> +     (list phonon qtbase vlc))
>>      (home-page "https://community.kde.org/Phonon")
>>      (synopsis "Phonon backend which uses VLC")
>>      (description "Phonon makes use of backend libraries to provide sound.
>>
>> base-commit: 5794926bed6fad4598bb565fb7f49be4205b11a1
>
>i think maybe also add a qt5 version? some package use phonon with qt5.

Sughosha