if SDL_EnumUnixAudioDevices() fails to find any devices,
set an error message on the exit path. Without this,
SDL_Init() could fail without any message available
in SDL_GetError().
- no need to keep the error in a static variable
- always print the error code
- reduce the required stack-size
- reduce the number of snprintf calls (and code size)
The io_list_check_add() and io_list_remove() functions are only ever called from within the Pipewire thread loop, so the locks are redundant. io_list_sort() is called from within a lock in the device detection function, so those additional locks are redundant as well.
Remove the hard upper limit of 8192 samples and instead use the buffer sizes provided by Pipewire to determine the size of the intermediate input buffer and whether double buffering is required for output streams. This allows for higher latency streams to potentially avoid double-buffering in the output case, and we can guarantee that the intermediate input buffer will always be large enough to handle whatever Pipewire may deliver.
As the buffer size calculations occur in a callback in the Pipewire processing thread itself, the stream readiness check has been modified to wait on two distinct flags set when the buffers have been configured and when the stream is ready and running.
The context and stream creation functions will destroy the passed properties object on failure, so no need to do it manually.
The pw_properties_free() function pointer is no longer needed, so it can be removed.
- drop unnecessary hascapture check
- call SDL_InvalidParamError and return -1 in case the index is out of range
- do not zfill SDL_AudioSpec
- adjust documentation to reflect the behavior
- reorganize the loop which checks for the right wave-format
- use the return value of UpdateAudioStream
- ensure SetError is called in SDL_NewAudioStream
- use SDL_bool if possible
- assume NULL/SDL_FALSE filled impl
- skip zfill of current_audio at the beginning of SDL_AudioInit (done before the init() calls)
Pipewire, as of 0.3.22, uses client config files to load modules instead of explicitly specifying them (PW_KEY_CONTEXT_PROFILE_MODULES is deprecated). Use the new method to load the realtime module to boost the audio thread priority.
This is to workaround systems where we hang in playback because the buffer
does not report the space for whatever reason. The system will instead block
in PlayDevice, which always immediately follows WaitDevice in modern times
so this works out, and it seems to keep the device moving forward.
For a future revision, we are either going to clean this up more properly,
or attempt to move to PulseAudio's pa_stream_set_write_callback() API, but
this will do for SDL 2.0.18.
Reference #4387 for discussion and further information.
