Bug 469259

Summary: strange voices when increasing the play speed
Product: [Applications] kasts Reporter: kde.85zhb
Component: generalAssignee: bart
Status: CONFIRMED ---    
Severity: normal CC: kde
Priority: NOR    
Version First Reported In: 23.01.0   
Target Milestone: ---   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description kde.85zhb 2023-05-02 11:55:56 UTC
SUMMARY
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STEPS TO REPRODUCE
1. download a podcast
2. play the podcast
3. increase speed to 1.5 for example

OBSERVED RESULT
voices are deformed making it impossible to listen
issue didnt happen to 2022.09 on Fedora 37

EXPECTED RESULT
normal voices speed up

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: fedora37/38
(available in About System)
KDE Plasma Version: 5.27.4
KDE Frameworks Version: 5.105.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION
I used to downgrade on fedora 37 but the version 2022.9 is not available on fedora 38.
other podcast apps are awful
Comment 1 bart 2023-05-02 12:00:47 UTC
Does it sound like the voices are higher pitched?
Can you look in the general settings and report which audio backend is in use?
It should be VLC, otherwise the package was not built correctly by the fedora packager.
(For the time being, it might help to switch to the gstreamer backend manually.)
Comment 2 kde.85zhb 2023-05-02 12:10:05 UTC
(In reply to bart from comment #1)
> Does it sound like the voices are higher pitched? 
Yes voices are higher pitched
> Can you look in the general settings and report which audio backend is in
> use?
Select Audio Backend is Qt Multimedia
> It should be VLC, otherwise the package was not built correctly by the
> fedora packager. 
So install the flatpak should fix it ?
> (For the time being, it might help to switch to the gstreamer backend
> manually.)
I can't select any other audio backend. Only choice is QT
Comment 3 bart 2023-05-02 12:21:23 UTC
Mmm, further investigation shows that fedora simply doesn't have VLC at all.
It should probably have been compiled with gstreamer support to be able to fall back to that, though.

Yes, switching to the flatpak version will solve the issue, if you're fine with that.

PS: The backend change was needed because the old audio backend solution for the pitch will not work with qt6 which we are switching to this year.
Comment 4 kde.85zhb 2023-05-02 12:25:59 UTC
I've switched to flatpak, works well.
Workaround is good enough for me
thank you very much for the quick answers
Comment 5 Andrew Smith 2024-03-18 12:34:05 UTC
I've noticed this issue on the Android version. Is there the option to install other sound backends there too?
Comment 6 bart 2024-03-18 12:40:31 UTC
(In reply to Andrew Smith from comment #5)
> I've noticed this issue on the Android version. Is there the option to
> install other sound backends there too?

This is a semi-related issue: the android audio backend never had support for resampling to correct for pitch.

Co-incidentally I have been searching for suitable other backends that would allow this.  Only last week I managed to get the MPV backend up-and-running for android, and that has support for pitch correction.  So there now is a possible solution available.  However, I cannot guarantee when this feature will be finished.