Slider with audio playback can crash QLC+
Posted: Tue Nov 22, 2022 11:15 am
Hi,
QLC+ 4.12.6
Windows 7, Windows 10, Linux Mint 21
I had QLC+ crash on me during a theatrical show, at a crucial point when there should have been a blackout and a sound cue. The actors were left bewildered in full stage light.
The show was run from a fairly complex virtual console, and a ten minute sound effect was running at the point the new sound and light cues were required. There was no response from any VC widget, or from the Stop ALL Functions button. QLC had to be terminated using Windows Task Manager.
I have simplified the workspace, attached as "Audio Slider Test.zip", which includes an audio file. The crash state can be provoked by running the Virtual Console, raising the "Long Sound" slider to around 30%, and then dipping it back to zero and up again twice in approximately one second. You might have to do this several times, but eventually it should produce the non-responsive state, at which point the playback will no longer respond to the slider. When the sound eventually stops the debug log file contains :-
"QCoreApplication::postEvent: Unexpected null receiver"
The Stop ALL Functions button will still be highlighted, even though there are no functions apparently executing. There will be no response to Stop ALL Functions, or the window exit button. I did not (knowingly) manipulate the slider in this fashion during the show, but it seems to reproduce the same state that I experienced.
The chance of producing a crash increases with the length of the audio, forum rules on file size mean that I have to post an mp3 of about 80 seconds duration, if you substitute a longer file it is MUCH more likely that you will reproduce the fault.
The crash occurs uder Windows 7 on a desktop, and Windows 10 on three separate laptops, but not under Linux Mint 21 (which has other audio shortcomings).
The crash can also be provoked with .wav files as well as .mp3.
The sliders in my show were connected to Akai APC Mini sliders; these are not essential to the crash, but maybe the detection of zero/non-zero state aggravates the problem?
I would be very grateful if the developers could look into this, as I prefer to control the audio directly with a slider, rather than use loopback to a submaster.
Richard
QLC+ 4.12.6
Windows 7, Windows 10, Linux Mint 21
I had QLC+ crash on me during a theatrical show, at a crucial point when there should have been a blackout and a sound cue. The actors were left bewildered in full stage light.
The show was run from a fairly complex virtual console, and a ten minute sound effect was running at the point the new sound and light cues were required. There was no response from any VC widget, or from the Stop ALL Functions button. QLC had to be terminated using Windows Task Manager.
I have simplified the workspace, attached as "Audio Slider Test.zip", which includes an audio file. The crash state can be provoked by running the Virtual Console, raising the "Long Sound" slider to around 30%, and then dipping it back to zero and up again twice in approximately one second. You might have to do this several times, but eventually it should produce the non-responsive state, at which point the playback will no longer respond to the slider. When the sound eventually stops the debug log file contains :-
"QCoreApplication::postEvent: Unexpected null receiver"
The Stop ALL Functions button will still be highlighted, even though there are no functions apparently executing. There will be no response to Stop ALL Functions, or the window exit button. I did not (knowingly) manipulate the slider in this fashion during the show, but it seems to reproduce the same state that I experienced.
The chance of producing a crash increases with the length of the audio, forum rules on file size mean that I have to post an mp3 of about 80 seconds duration, if you substitute a longer file it is MUCH more likely that you will reproduce the fault.
The crash occurs uder Windows 7 on a desktop, and Windows 10 on three separate laptops, but not under Linux Mint 21 (which has other audio shortcomings).
The crash can also be provoked with .wav files as well as .mp3.
The sliders in my show were connected to Akai APC Mini sliders; these are not essential to the crash, but maybe the detection of zero/non-zero state aggravates the problem?
I would be very grateful if the developers could look into this, as I prefer to control the audio directly with a slider, rather than use loopback to a submaster.
Richard