gst/pwaudiosink: set the default latency time (buffer size) to be 21.3ms

This is to solve underrun issues that seem to appear with the default
10ms latency that GstBaseAudioSink has.
Hopefully in the future we will have a better mechanism to pick
the appropriate latency instead of hardcoding it here.

Upstream-Status: Submitted [PipeWire#140]

src/gst/gstpwaudiosink.c

@@ -57,6 +57,13 @@ static void
 gst_pw_audio_sink_init (GstPwAudioSink * self)
 {
   self->props.fd = -1;
+
+  /* Bump the default buffer size up to 21.3 ms, which is the default on most
+   * sound cards, in hope to match the alsa buffer size on the pipewire server.
+   * This may not always happen, but it still sounds better than the 10ms
+   * default latency. This is temporary until we have a better mechanism to
+   * select the appropriate latency */
+  GST_AUDIO_BASE_SINK (self)->latency_time = 21333;
 }
 
 static void