Only consider linear frames for talk detection -- ignore anything else (bug #2219)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@3594 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_talkdetect.c

@@ -130,7 +130,7 @@ static int background_detect_exec(struct ast_channel *chan, void *data)
 							ast_frfree(fr);
 							break;
 						}
-					} else if (fr->frametype == AST_FRAME_VOICE) {
+					} else if ((fr->frametype == AST_FRAME_VOICE) && (fr->subclass == AST_FORMAT_SLINEAR)) {
 						int totalsilence;
 						int ms;
 						res = ast_dsp_silence(dsp, fr, &totalsilence);