Added MixMonitorMute manager command

Added a new manager command to mute/unmute MixMonitor audio on a channel. 
Added a new feature to audiohooks so that you can mute either read / write
(or both) types of frames - this allows for MixMonitor to mute either side
of the conversation without affecting the conversation itself.

(closes issue #16740)
Reported by: jmls

Review: https://reviewboard.asterisk.org/r/487/



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@258190 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/audiohook.h

@@ -62,6 +62,8 @@ enum ast_audiohook_flags {
 	 * slinfactories. We will flush the factories if they contain too many samples.
 	 */
 	AST_AUDIOHOOK_SMALL_QUEUE = (1 << 3),
+	AST_AUDIOHOOK_MUTE_READ = (1 << 4),     /*!< audiohook should be mute frames read */
+	AST_AUDIOHOOK_MUTE_WRITE = (1 << 5),    /*!< audiohook should be mute frames written */
 };
 
 #define AST_AUDIOHOOK_SYNC_TOLERANCE 100 /*< Tolerance in milliseconds for audiohooks synchronization */
@@ -277,6 +279,16 @@ int ast_audiohook_volume_get(struct ast_channel *chan, enum ast_audiohook_direct
  */
 int ast_audiohook_volume_adjust(struct ast_channel *chan, enum ast_audiohook_direction direction, int volume);
 
+/*! \brief Mute frames read from or written to a channel
+ * \param chan Channel to muck with
+ * \param source Type of audiohook
+ * \param flag which direction to set / clear
+ * \param clear set or clear muted frames on direction based on flag parameter
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int ast_audiohook_set_mute(struct ast_channel *chan, const char *source, enum ast_audiohook_flags flag, int clear);
+
 #if defined(__cplusplus) || defined(c_plusplus)
 }
 #endif

include/asterisk/frame.h

@@ -728,6 +728,11 @@ static force_inline int ast_format_rate(format_t format)
 	}
 }
 
+/*!
+ * \brief Clear all audio samples from an ast_frame. The frame must be AST_FRAME_VOICE and AST_FORMAT_SLINEAR 
+ */
+int ast_frame_clear(struct ast_frame *frame);
+
 #if defined(__cplusplus) || defined(c_plusplus)
 }
 #endif