- support for sub-devices;
- fixed 24-bit format support for some devices which on little-endian machine operate only in big-endian format, example of such device is Audio4DJ which supports only SND_PCM_FORMAT_S24_3BE (for this patch implemented support only for 24-bit audio samples although other formats may be added in case of necessity and if such devices exist);
! special thanks to Owen Williams from Mixxx project who tested these changes/fixes on real Audio4DJ device.
- implemented dynamic ALSA loading, you shall define PA_ALSA_DYNAMIC when compiling PortAudio library, by default PortAudio will use compile time linkage;
- added PA_ALSA_PATHNAME define to redefine ALSA library path and filename to some other name and location, has effect only together with PA_ALSA_DYNAMIC;
- added extension function (PaAlsa_SetLibraryPathName) which allows to set ALSA library path and filename during application run-time overwriting default set by PA_ALSA_PATHNAME during compilation;
- added API compatibility with Android OS (although ALSA may not be available on your device and usually requires 'root' access rights to open an audio device), some missing ALSA functions are replaced with stubs (needs more input from interested parties), to compile on Android you need to add ALSA headers (get it from Android GIT source-code tree) to compiler's searchable path.
- fixed callback thread to exit normally if error condition was satisfied during stream processing (OnExit wasn't called), it was possible cause of crash if error happened inside the thread
- modified processing thread to timeout during poll() within around 2 seconds instead of 64 milliseconds, this will help to fix problems on systems with low processing power and possible CPU overloading, like portable ARM devices
- timeout of poll() will not cause stream to stop but will cause Alsa stream restart, poll timeout will now set 'xrun' event to 1
- trying to fix specific case of stream failing to open when min/max period is specifying fixed value with +/-1 difference, we try choosing middle then which seems to be aligned to 2
- improved host buffer size calculation: taking into account obligatory double buffering utilising formula (userFrames + MAX( userFrames, SR * suggestedLatency)), aligning host buffer with user buffer size, additional testing of host buffer size to avoid failure on snd_pcm_hw_params_set_period_size_near, additional logging for more convenient debugging
- fixed seg.fault (caused by assertion) when using non-interleaved host i/o, now paNonInterleaved flag is provided to PaUtil_InitializeBufferProcessor to signal processor about host format being non-interleaved
- fixed latency setting dependence on user buffer size, now it is completely independent and user is able to set lowest possible/audible latency (approx. 3-4ms)
- fixed fixed min. latency for non-MMAPed devices, they do behave similar to MMAPed devices now without a limitation
- reverted buffer size (2048) hardcoding for non-MMAPed devices to avoid crash on wrong buffer size usage (whole area requires more work)
- optimized non-MMAPed device operation to avoid malloc(memset)/free usage on every processing call avoiding significant performance penalty
- fixed deadlock in PaAlsaStream_WaitForFrames if device is paused, poll() results are now checked for 0 and if 64 times exceeded an error (paTimedOut) is returned
- removed hardcoded low-limit of latency for non-MMAPed devices, it is an obligation for user to set an acceptable/desired latency value
- tuned XRUN recovery sequence for MMAPed devices
