From f279257c5465461d88e2d2ec381cc10bd8e726ab Mon Sep 17 00:00:00 2001
From: Andrew Bonney <address@hidden>
Date: Tue, 4 Jun 2013 09:29:27 +0100
Subject: [PATCH 1/4] Prevent MTU breaches for L16 stereo

---
 src/audiofilters/l16.c |   39 ++++++++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/src/audiofilters/l16.c b/src/audiofilters/l16.c
index 646e1b5..70d8b64 100644
--- a/src/audiofilters/l16.c
+++ b/src/audiofilters/l16.c
@@ -25,10 +25,16 @@ struct EncState {
 	int ptime;
 	int rate;
 	int nchannels;
-	int nbytes;
+	int mtu;
 	MSBufferizer *bufferizer;
 };
 
+static void enc_update_mtu(struct EncState *s){
+	int max_payload = ms_get_payload_max_size();
+	// Packet sizes must be exactly divisible by 4 for L16 stereo to work
+	s->mtu = max_payload - (max_payload % 2*s->nchannels);
+}
+
 static void enc_init(MSFilter *f)
 {
 	struct EncState *s=(struct EncState*)ms_new(struct EncState,1);
@@ -37,6 +43,7 @@ static void enc_init(MSFilter *f)
 	s->ptime = 10;
 	s->rate=8000;
 	s->nchannels = 1;
+	enc_update_mtu(s);
 	f->data=s;
 };
 
@@ -48,13 +55,7 @@ static void enc_uninit(MSFilter *f)
 	f->data = 0;
 };
 
-static void enc_update(struct EncState *s){
-	s->nbytes=(2*s->nchannels*s->rate*s->ptime)/1000;
-}
-
 static void enc_preprocess(MSFilter *f){
-	struct EncState *s=(struct EncState*)f->data;
-	enc_update(s);
 }
 
 static void host_to_network(int16_t *buffer, int nsamples){
@@ -77,14 +78,19 @@ static void enc_process(MSFilter *f){
 	ms_filter_lock(f);
 	ms_bufferizer_put_from_queue(s->bufferizer,f->inputs[0]);
 	
-	while(ms_bufferizer_get_avail(s->bufferizer)>=s->nbytes) {
-		mblk_t *om=allocb(s->nbytes,0);
-		om->b_wptr+=ms_bufferizer_read(s->bufferizer,om->b_wptr,s->nbytes);
-		host_to_network((int16_t*)om->b_rptr,s->nbytes/2);
+	int bytes_to_send = 0;
+	while((bytes_to_send=ms_bufferizer_get_avail(s->bufferizer))>0) {
+		if (bytes_to_send > s->mtu) {
+			bytes_to_send = s->mtu;
+		}
+		mblk_t *om=allocb(bytes_to_send,0);
+		om->b_wptr+=ms_bufferizer_read(s->bufferizer,om->b_wptr,bytes_to_send);
+		host_to_network((int16_t*)om->b_rptr,bytes_to_send/2);
 		mblk_set_timestamp_info(om,s->ts);
 		ms_queue_put(f->outputs[0],om);
-		s->ts += s->nbytes/(2*s->nchannels);
+		s->ts += bytes_to_send/(2*s->nchannels);
 	}
+
 	ms_filter_unlock(f);
 };
 
@@ -92,7 +98,6 @@ static void set_ptime(struct EncState *s, int value){
 	if (value>0 && value<=100){
 		s->ptime=value;
 		ms_message("L16 encoder using ptime=%i",value);
-		enc_update(s);
 	}
 }
 
@@ -129,6 +134,13 @@ static int enc_set_sr(MSFilter *f, void *arg){
 static int enc_set_nchannels(MSFilter *f, void *arg) {
 	struct EncState *s = (struct EncState *)f->data;
 	s->nchannels = *(int *)arg;
+	enc_update_mtu(s);
+	return 0;
+}
+
+static int enc_set_mtu(MSFilter *f, void*data){
+	struct EncState *s=(struct EncState *)f->data;
+	enc_update_mtu(s);
 	return 0;
 }
 
@@ -137,6 +149,7 @@ static MSFilterMethod enc_methods[]={
 	{	MS_FILTER_ADD_FMTP		,	enc_add_fmtp},
 	{	MS_FILTER_SET_SAMPLE_RATE	,	enc_set_sr	},
 	{	MS_FILTER_SET_NCHANNELS		,	enc_set_nchannels},
+	{	MS_FILTER_SET_MTU		,	enc_set_mtu},
 	{	0				,	NULL		}
 };
 
-- 
1.7.9.5