Currently AudioIoCallback::ScrubState::Get(), inserts a period of silence the first time it's called because at this time Scrubber::ContinueScrubbingPoll() has not been called, and so message.end has not been set to an appropriate value.
In the case of keyboard scrubbing and play-at-speed, the initial speed is already known, so message.end can be set to this value, removing the need for an initial silence.
The start of keyboard scrubbing and play-at-speed are now faster (the latter very much faster).
If one of the keyboard scrubbing keys is being held down, and the other keyboard scrubbing key is pressed:
1. With current behaviour, scrubbing in the other direction only starts when the original key is released - scrubbing stops and then starts in the other direction.
2. With the new behaviour, scrubbing immediately changes direction, and does not stop when the original key is released - scrubbing does not stop and then start again.
New behaviour:
If one of the keyboard scrubbing keys is being held down,
Problem:
On Windows, after 50ms, there is a short period of roughly zero introduced into the output. On Linux, there is also a spike which sounds like a crackle.
In AudioIO::FillBuffers(), Mixer::SetTimesAndSpeed() is called, which sets mT0 and mT1 to a small interval.
In Mixer::MixVariableRates(), all the samples in the interval are used, which means the Resample::Process() is called with last equal to true.
So when Mixer::MixVariableRates() is called again, the resampler is being reused after a call to Process() in which last is true.
It is not stated in the soxr documentation if the resampler will produce valid results in this case, and it's only the scrubbing code which does this.
I think this is the problem, and so the partial fix below avoids this happening.
Partial fix for play-at-speed and keyboard scrubbing:
For these, there is no need to reset the values of mT0 and mT1. (There is no need to allow for the sample position being used to potentially jump around.)
So for these cases, Mixer::SetSpeed() is called, rather than Mixer::SetTimesAndSpeed().
Instead of only when recording (it broke monitoring), now Audacity
will prevent the system from sleeping while any audio I/O is active.
This might be a little strong-handed though and maybe should be a
preference option.
... though in a small cycle with each other, by moving RealtimeEffectManager to
new files, which remain in the big component.
Net loss of 1, the big component now has 27 files
... New files, but (almost) empty; don't use the global variable gAudioIO,
but use one of two accessor function names (which are the same function for
now).
AudioIOBase will have fewer dependencies than AudioIO -- in particular, no
dependency on tracks.
It won't include StartStream. It will contain functions to query the
present state of streams, and device capabilities.
... as a preparation for splitting up class AudacityProject.
Use ProjectWindow as an alias for AudacityProject, and fetch it from the
project with a static member function, where certain of its services are used;
pretending they are not the same class.
Use global accessor functions to get wxFrame from the project where only
wxFrame's member functions are needed, so there will be less dependency on
ProjectWindow when it becomes a distinct class.
... Rename it as SetStatus; make it part of AudacityProject not
TrackPanelListener; and use a roundabout event signalling to cause the timer
restart.
Because SetStatus will be one of very few things left in AudacityProject, but
the timer handling will be part of another class decoupled from it.
And TrackPanelListener won't really be needed: TrackPanel will not need to
pretend it doesn't know what an AudacityProject is.
... Unnecessary because transitively included.
But each .cpp file still includes its own .h file near the top to ensure
that it compiles indenendently, even if it is reincluded transitively later.
... but see code comments about the apparent original intent, to update some
other preference instead; which I don't do, thus preserving present behavior
... following the substitute, don't concatenate rule in many places.
The end users have commands to generate these reports in menus, so they should
be translated then; however, they are also part of crash reports meant for
developers, so temporarily set English locale for generating those.
... except Audacity.h; and in no others.
Do so even if Experimental.h gets multiply included, as in both the .h and
.cpp files.
This makes it easier to do a text scan to be sure there are no unintended quiet
changes of meaning because of omission of Experimental.h when the flag is
an enabled one.
Also move inclusions of Experimental.h earlier.
Also don't require Experimental.h to be preceded by Audacity.h to define
EXPERIMENTAL_MIDI_OUT correctly.
