wasapisrc: Try harder to avoid debug output in the hot loop

The whole `src_read()` function is a hot loop since the ringbuffer
thread is waiting on us, and printing to the console from inside it
can easily cause us to miss our deadline.

F.ex., if you had GST_DEBUG=3 and we accidentally missed a device
period, we'd trigger the "reported glitch" warning, which would cause
us to miss another device period, and so on. Let's reduce the log
level so that GST_DEBUG=3 is more usable, and only print buffer flag
info when it's actually relevant.

diff --git a/sys/wasapi/gstwasapisrc.c b/sys/wasapi/gstwasapisrc.c
index cd70448..63357c1 100644 (file)
--- a/sys/wasapi/gstwasapisrc.c
+++ b/sys/wasapi/gstwasapisrc.c
@@ -611,15 +611,17 @@ gst_wasapi_src_read (GstAudioSrc * asrc, gpointer data, guint length,
           goto err);
     }
 
-    if (flags != 0)
-      GST_INFO_OBJECT (self, "buffer flags=%#08x", (guint) flags);
-
     /* XXX: How do we handle AUDCLNT_BUFFERFLAGS_SILENT? We're supposed to write
      * out silence when that flag is set? See:
      * https://msdn.microsoft.com/en-us/library/windows/desktop/dd370800(v=vs.85).aspx */
 
-    if (flags & AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY)
-      GST_WARNING_OBJECT (self, "WASAPI reported glitch in buffer");
+    if (G_UNLIKELY (flags != 0)) {
+      /* https://docs.microsoft.com/en-us/windows/win32/api/audioclient/ne-audioclient-_audclnt_bufferflags */
+      if (flags & AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY)
+        GST_DEBUG_OBJECT (self, "WASAPI reported discontinuity (glitch?)");
+      if (flags & AUDCLNT_BUFFERFLAGS_TIMESTAMP_ERROR)
+        GST_DEBUG_OBJECT (self, "WASAPI reported a timestamp error");
+    }
 
     /* Copy all the frames we got into the adapter, and then extract at most
      * @wanted size of frames from it. This helps when ::GetBuffer returns more