--- asterisk-11.5.0.o/formats/format_g729.c	2012-04-29 21:50:57.000000000 +0200
+++ asterisk-11.5.0/formats/format_g729.c	2013-08-07 21:10:51.760016214 +0200
@@ -42,9 +42,16 @@
 
 /* Portions of the conversion code are by guido@sienanet.it */
 
-#define	BUF_SIZE	20	/* two G729 frames */
+#define G729A_FRAME_SIZE   10
+#define	BUF_SIZE	       (G729A_FRAME_SIZE * 2)	/* two G729 frames */
+#define G729A_CNG_SIZE     2
 #define	G729A_SAMPLES	160
 
+struct ast_g729_pvt
+{
+	int detected_vad; /* simple flag indicating whether or not we detected and reported on VAD on this stream yet or not */
+};
+
 static struct ast_frame *g729_read(struct ast_filestream *s, int *whennext)
 {
 	int res;
@@ -55,7 +62,7 @@
 	s->fr.samples = G729A_SAMPLES;
 	AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, BUF_SIZE);
 	if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) != s->fr.datalen) {
-		if (res && (res != 10))	/* XXX what for ? */
+		if (res && (res != G729A_FRAME_SIZE))	/* XXX what for ? */
 			ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
 		return NULL;
 	}
@@ -65,7 +72,8 @@
 
 static int g729_write(struct ast_filestream *fs, struct ast_frame *f)
 {
-	int res;
+	struct ast_g729_pvt* pvt = fs->_private;
+	int res, writelen = f->datalen;
 	if (f->frametype != AST_FRAME_VOICE) {
 		ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
 		return -1;
@@ -74,12 +82,20 @@
 		ast_log(LOG_WARNING, "Asked to write non-G729 frame (%s)!\n", ast_getformatname(&f->subclass.format));
 		return -1;
 	}
-	if (f->datalen % 10) {
-		ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 10\n", f->datalen);
+	if (f->datalen % G729A_FRAME_SIZE) {
+		if (f->datalen % G729A_FRAME_SIZE == G729A_CNG_SIZE) {
+			writelen -= G729A_CNG_SIZE;
+			if (!pvt->detected_vad) {
+				ast_log(LOG_WARNING, "Probable CNG parameter update detected, this is a bug in the sender who should not be sending CNG updates - try and switch off Voice Activity Detected (VAD) or Silence Suppression on the sender.\n");
+				pvt->detected_vad = 1;
+			}
+		} else {
+			ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of %d\n", f->datalen, G729A_FRAME_SIZE);
 		return -1;
 	}
-	if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
-			ast_log(LOG_WARNING, "Bad write (%d/10): %s\n", res, strerror(errno));
+	}
+	if ((res = fwrite(f->data.ptr, 1, writelen, fs->f)) != writelen) {
+			ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, writelen, strerror(errno));
 			return -1;
 	}
 	return 0;
@@ -143,6 +159,7 @@
 	.tell = g729_tell,
 	.read = g729_read,
 	.buf_size = BUF_SIZE + AST_FRIENDLY_OFFSET,
+	.desc_size = sizeof(struct ast_g729_pvt),
 };
 
 static int load_module(void)