Bug 1531833 - Add a cubeb pref to indicate the this audio input and output streams will transport voice. r?kinetik

include/cubeb/cubeb.h

@@ -223,10 +223,16 @@ enum {
 /** Miscellaneous stream preferences. */
 typedef enum {
   CUBEB_STREAM_PREF_NONE     = 0x00, /**< No stream preferences are requested. */
-  CUBEB_STREAM_PREF_LOOPBACK = 0x01 /**< Request a loopback stream. Should be
+  CUBEB_STREAM_PREF_LOOPBACK = 0x01, /**< Request a loopback stream. Should be
                                          specified on the input params and an
                                          output device to loopback from should
                                          be passed in place of an input device. */
+  CUBEB_STREAM_PREF_VOICE = 0x04  /**< This stream is going to transport voice data.
+                                       Depending on the backend and platform, this can
+                                       change the audio input or output devices
+                                       selected, as well as the quality of the stream,
+                                       for example to accomodate bluetooth SCO modes on
+                                       bluetooth devices. */
 } cubeb_stream_prefs;
 
 /** Stream format initialization parameters. */