Features a lot of timeline-related cache optimizations as well as general
optimizations and improvements in timeline behavior. Should improve
usability significantly.
macOS audio playback failed due to audio being processed in the main thread.
Now all audio playback has been placed into its own high priority thread to
always keep up better with the operating system's demands.
This system was kind of janky anyway. It makes more sense ultimately for the
audio management classes to contain the file handle rather than the renderer.
There's no real reason not to use float for audio. It's light on system
resources (compared to everything else we're doing at least) and the code
becomes simpler when we can assume all audio will be -1 to 1 rather than 0 to
255 or -32768 to 32767.
The only thing we might want to do one day is move up to SAMPLE_FMT_DBL, but
this should only take some mild refactoring and all our assumptions (i.e. -1 to
1 range, etc.) can remain the same.
Fixes a number of playback stuttering and general UI lag issues by setting all
background tasks to IdlePriority rather than LowPriority. While it was assumed
LowPriority tasks would always get scheduled below NormalPriority (e.g. main
thread) tasks, it turns out this is not always the case. If the background tasks
start consuming a lot of CPU cycles, the scheduler may use "dynamic scheduling"
to schedule them above the main thread regardless leading to UI lag. This is
apparently the case for all thread priorities apart from IdlePriority, which
is allegedly a special case where threads are *only* scheduled when other
threads aren't busy ensuring the main thread stays responsive.
Implementation isn't perfect yet, viewer/renderer doesn't update yet when
the preference is changed so a sequence needs to be re-opened for the change to
take effect.
Previously the audio output manager was a "hybrid device" that acted as a pull
device for audio devices and as a push device and device proxy for the rest of
the application. This approach turned out to be flawed, particularly in the
frequent opening and closing of the audio device (extremely slow). Since we
use both pulling (for constant playback) and pushing (audio scrubbing, short
bursts of sound), it needed a similar but different approach. This approach
will switch the output device from push mode (default) to pull mode (during
playback) only when necessary resulting in far less UI lag (basically
unnoticeable now) than the previous approach.
Many changes were made throughout the codebase to support audio, these are
most of the small changes necessary.
The audio support still is not perfect. I still need to write in resampling
support. After that it should work correctly with all audio types.
itsmattkc