Bug 441766 - Volume amplitude visualization does not scale correctly with the set maximum volume amplitude
Summary: Volume amplitude visualization does not scale correctly with the set maximum ...
Status: RESOLVED INTENTIONAL
Alias: None
Product: plasmashell
Classification: Plasma
Component: Audio Volume widget (other bugs)
Version First Reported In: 6.2.4
Platform: Other Linux
: LO minor
Target Milestone: 1.0
Assignee: David Rosca
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-08-30 16:47 UTC by postix
Modified: 2025-01-21 14:20 UTC (History)
7 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
Screenrecording of plasma-pa's application tab (646.50 KB, video/x-matroska)
2021-08-30 16:47 UTC, postix
Details
Screenrecording: Application's tab: pavucontrol vs plasma-pa (1.12 MB, video/x-matroska)
2021-08-31 11:19 UTC, postix
Details
Screenrecording: Device's tab: pavucontrol vs plasma-pa (1.05 MB, video/x-matroska)
2021-08-31 11:25 UTC, postix
Details

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Description postix 2021-08-30 16:47:57 UTC
Created attachment 141156 [details]
Screenrecording of plasma-pa's application tab

SUMMARY


STEPS TO REPRODUCE
1. Play some music: Set the volume slider to 50% in your music app
2. Set the device output volume to 100%
3. Adjust your set up you can hear the music when the application's volume in plasma-pa is set to 20%
4. Observe the amplitude visualization when changing the applications volume in plasma-pa

OBSERVED RESULT

The visualization is around 5% and doesn't start moving at all until the slider is at around 40%, where the music becomes actually loud.
The line-out visualized amplitude is always around 20% maximum.


EXPECTED RESULT

The slider resembles the volume output more realistically.


SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20210823
KDE Plasma Version: 5.22.4
KDE Frameworks Version: 5.85.0
Qt Version: 5.15.2
Kernel Version: 5.13.12-1-default (64-bit)
Graphics Platform: X11

ADDITIONAL INFORMATION
Scaling: 2.0
Comment 1 David Redondo 2021-08-31 09:01:17 UTC
Does pavucontrol display it in the same way or some other way?
Comment 2 postix 2021-08-31 11:19:35 UTC
Created attachment 141178 [details]
Screenrecording: Application's tab: pavucontrol vs plasma-pa

(In reply to David Redondo from comment #1)
> Does pavucontrol display it in the same way or some other way?

There are clearly differences between the two applications. W/o having looked at the code it seems to me that the maximal possible amplitude of plasma-pa is normalized to the position of the slider. Is that correct?
It seems when the slider is around 25-50% the amplitude if plasma-pa is about 1/4 or 1/2 of pavucontrol's. At 100% they seem to be practically equal.
Comment 3 postix 2021-08-31 11:25:03 UTC
Created attachment 141179 [details]
Screenrecording: Device's tab: pavucontrol vs plasma-pa

For the line-out the difference is more severe: While at 1% plasma-pa's output only shows a static blue beginning of a line, pavucontrol's bar already jumps up to 50%.
Comment 4 David Redondo 2021-08-31 12:12:41 UTC
>W/o having looked at the code it seems to me that the maximal possible amplitude of plasma-pa is normalized to the position of the slider. Is that correct?

Yes, so if we have 100% in pavucontrol, it should go to the slider handle in plasma.
Comment 5 TraceyC 2025-01-15 17:23:59 UTC
I'm still able to reproduce this in 6.2.5 and git-master
Comment 6 Bug Janitor Service 2025-01-20 16:12:25 UTC
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-pa/-/merge_requests/315
Comment 7 Marco Martin 2025-01-21 14:20:52 UTC
from the discussion on the merge request, we conclude we prefer the volume amplitude indicator scaling only until the slider and never beyond, which is the current behavior (and why is different form pavucontrol) so marking this as intentional