Audacity freezes when quickly starting and stopping playback

[LWinterberg]

Bug description

No response

Steps to reproduce

1. have a track
2. mash spacebar to send many start and stop instructions
3. freeze

Expected behavior

When more inputs are sent than Audacity can process, additional inputs should be discarded.

Actual behavior

No response

Audacity Version

latest stable version (from audacityteam.org/download)

Operating system

Windows

Additional context

I've seen two users report this bug on socials and forum, so it's at least slightly frequently encountered.

When I pause Audacity in the VSCode debugger after it hits the freeze, I end up with the following call stack:

view call stack

ntdll.dll!00007ffd30924204() (Unknown Source:0)
ntdll.dll!00007ffd308db873() (Unknown Source:0)
KernelBase.dll!00007ffd2dd9b391() (Unknown Source:0)
msvcp140d.dll!00007ffc91302ede() (Unknown Source:0)
Audacity.exe!std::this_thread::sleep_until<std::chrono::steady_clock,std::chrono::duration<__int64,std::ratio<1,1000000000>>>(const std::chrono::time_point<std::chrono::steady_clock,std::chrono::duration<__int64,std::ratio<1,1000000000>>> & _Abs_time) Line 201 (c:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\thread:201)
Audacity.exe!std::this_thread::sleep_for<__int64,std::ratio<1,1000>>(const std::chrono::duration<__int64,std::ratio<1,1000>> & _Rel_time) Line 207 (c:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\thread:207)
Audacity.exe!AudioIoCallback::WaitForAudioThreadStopped() Line 3246 (c:\Users\mc\Documents\GitHub\audacity\src\AudioIO.cpp:3246)
Audacity.exe!AudioIO::StopStream() Line 1408 (c:\Users\mc\Documents\GitHub\audacity\src\AudioIO.cpp:1408)
Audacity.exe!ProjectAudioManager::Stop(bool stopStream) Line 531 (c:\Users\mc\Documents\GitHub\audacity\src\ProjectAudioManager.cpp:531)
Audacity.exe!TransportUtilities::DoStopPlaying(const CommandContext & context) Line 163 (c:\Users\mc\Documents\GitHub\audacity\src\TransportUtilities.cpp:163)
Audacity.exe!TransportActions::Handler::OnPlayDefaultOrStop(const CommandContext & context) Line 184 (c:\Users\mc\Documents\GitHub\audacity\src\menus\TransportMenus.cpp:184)
Audacity.exe!CommandManager::HandleCommandEntry(AudacityProject & project, const CommandListEntry * entry, std::bitset<64> flags, bool alwaysEnabled, const wxEvent * evt, const CommandContext * pGivenContext) Line 1269 (c:\Users\mc\Documents\GitHub\audacity\src\commands\CommandManager.cpp:1269)
Audacity.exe!CommandManager::FilterKeyEvent(AudacityProject * project, const wxKeyEvent & evt, bool permit) Line 1190 (c:\Users\mc\Documents\GitHub\audacity\src\commands\CommandManager.cpp:1190)
Audacity.exe!<lambda_6>::operator()(wxKeyEvent & key) Line 1713 (c:\Users\mc\Documents\GitHub\audacity\src\commands\CommandManager.cpp:1713)
Audacity.exe!std::invoke<<lambda_6> &,wxKeyEvent &>(<lambda_6> & _Obj, wxKeyEvent & _Arg1) Line 1573 (c:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\type_traits:1573)
Audacity.exe!std::_Invoker_ret<bool>::_Call<<lambda_6> &,wxKeyEvent &>(<lambda_6> & _Func, wxKeyEvent & <_Vals_0>) Line 672 (c:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\functional:672)
Audacity.exe!std::_Func_impl_no_alloc<<lambda_6>,bool,wxKeyEvent &>::_Do_call(wxKeyEvent & <_Args_0>) Line 832 (c:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\functional:832)
Audacity.exe!std::_Func_class<bool,wxKeyEvent &>::operator()(wxKeyEvent & <_Args_0>) Line 879 (c:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.33.31629\include\functional:879)
Audacity.exe!GlobalHook<KeyboardCapture::PostFilter,bool __cdecl(wxKeyEvent &)>::Call<wxKeyEvent &>(wxKeyEvent & <arguments_0>) Line 162 (c:\Users\mc\Documents\GitHub\audacity\libraries\lib-utility\GlobalVariable.h:162)
Audacity.exe!`EventMonitor::FilterEvent'::`2'::<lambda_1>::operator()() Line 216 (c:\Users\mc\Documents\GitHub\audacity\src\KeyboardCapture.cpp:216)

[Paul-Licameli]

I suggest @pietro68 investigate this one

[pietro68]

I can not reproduce this. I tried with a Windows x64 vc2019, both Debug and Release.
Tried generating a mono noise track, then pressing the space bar many times as fast as possible.

[crsib]

I wonder if it depends on the Host type. I don't observe it on WASAPI, but I've reproduced it instantly on MME.

[pietro68]

I don't observe it on WASAPI, but I've reproduced it instantly on MME.

could you please tell me if you used a Debug or a Release build. I can not reproduce it using either MME or Directsound.

[crsib]

I've reproduced it in Debug build

[MagisterX]

I have encountered similar issue in 3.2. It's very easy to reproduce if you place playhead after audio track and click on play button or press space. Audacity will instantly freeze.
I tried to do the same with latest master build in Debug build and it was almost impossible to reproduce for some reason.
In my case one thread stuck in while condition of AudioIoCallback::WaitForAudioThreadStopped() method from AudioIO.cpp.
I tweaked values in debugger to bypass condition and Audacity unfreeze after that.
I used WASAPI. Also replicated on MME but not with DirectSound.

2022-09-25.15-25-36AVC.mp4

[petersampsonaudacity]

See also: Crash via left clicking play head bar and pushing space bar to play #3716