osxaudiosrc drops frames when osxaudiosink misses frames

Submitted by Ilya Konstantinov

Link to original bug (#753112)

Description

To reproduce:

$ gst-launch-1.0 osxaudiosrc ! identity drop-probability=0.1 ! osxaudiosink
Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstAudioSrcClock
WARNING: from element /GstPipeline:pipeline0/GstOsxAudioSrc:osxaudiosrc0: Can't record audio fast enough
Additional debug info:
gstaudiobasesrc.c(866): GstFlowReturn gst_audio_base_src_create(GstBaseSrc *, guint64, guint, GstBuffer **) (): /GstPipeline:pipeline0/GstOsxAudioSrc:osxaudiosrc0:
Dropped 9261 samples. This is most likely because downstream can't keep up and is consuming samples too slowly.
WARNING: from element /GstPipeline:pipeline0/GstOsxAudioSrc:osxaudiosrc0: Can't record audio fast enough

I don't quite understand why osxaudiosrc drops frames when the sink is the one that's not receiving all of the frames. This doesn't happen with fakesink or filesink.

Also, it's "solved" by setting "osxaudiosink sync=0".