Ticket #1042, minor updates related to AEC:

 - Added requirement of AEC minimal latency between reference and echo in aectest sample app.
 - Modified AEC latency in sound port to 3/4 of playback latency.
 - Few cleaned up echo_common.c: unused vars, a bit stricter latency check (to be at least as much as PTIME).



git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@3115 74dad513-b988-da41-8d7b-12977e46ad98

2 files changed, 18 insertions, 17 deletions

diff --git a/pjmedia/src/pjmedia/echo_common.c b/pjmedia/src/pjmedia/echo_common.c
index 962e975b..82eec6ea 100644
--- a/pjmedia/src/pjmedia/echo_common.c
+++ b/pjmedia/src/pjmedia/echo_common.c
@@ -24,6 +24,7 @@
 #include <pj/assert.h>
 #include <pj/list.h>
 #include <pj/log.h>
+#include <pj/math.h>
 #include <pj/pool.h>
 #include "echo_internal.h"
 
@@ -46,8 +47,6 @@ struct pjmedia_echo_state
     ec_operations   *op;
 
     pj_bool_t	     lat_ready;	    /* lat_buf has been filled in.	    */
-    unsigned	     lat_target_cnt;/* Target number of frames in lat_buf   */
-    unsigned	     lat_buf_cnt;   /* Actual number of frames in lat_buf   */
     struct frame     lat_buf;	    /* Frame queue for delayed playback	    */
     struct frame     lat_free;	    /* Free frame list.			    */
 
@@ -144,7 +143,7 @@ PJ_DEF(pj_status_t) pjmedia_echo_create2(pj_pool_t *pool,
 					 unsigned options,
 					 pjmedia_echo_state **p_echo )
 {
-    unsigned ptime;
+    unsigned ptime, lat_cnt;
     pjmedia_echo_state *ec;
     pj_status_t status;
 
@@ -194,22 +193,21 @@ PJ_DEF(pj_status_t) pjmedia_echo_create2(pj_pool_t *pool,
 
     /* Create latency buffers */
     ptime = samples_per_frame * 1000 / clock_rate;
-    if (latency_ms == 0) {
+    if (latency_ms > ptime) {
+	/* Normalize latency with delaybuf/WSOLA latency */
+	latency_ms -= PJ_MIN(ptime, PJMEDIA_WSOLA_DELAY_MSEC);
+    }
+    if (latency_ms < ptime) {
 	/* Give at least one frame delay to simplify programming */
 	latency_ms = ptime;
     }
-    ec->lat_target_cnt = latency_ms / ptime;
-    if (ec->lat_target_cnt != 0) {
-	unsigned i;
-	for (i=0; i < ec->lat_target_cnt; ++i)  {
-	    struct frame *frm;
-
-	    frm = (struct frame*) pj_pool_alloc(pool, (samples_per_frame<<1) +
-						      sizeof(struct frame));
-	    pj_list_push_back(&ec->lat_free, frm);
-	}
-    } else {
-	ec->lat_ready = PJ_TRUE;
+    lat_cnt = latency_ms / ptime;
+    while (lat_cnt--)  {
+	struct frame *frm;
+
+	frm = (struct frame*) pj_pool_alloc(pool, (samples_per_frame<<1) +
+						  sizeof(struct frame));
+	pj_list_push_back(&ec->lat_free, frm);
     }
 
     /* Create delay buffer to compensate drifts */
diff --git a/pjmedia/src/pjmedia/sound_port.c b/pjmedia/src/pjmedia/sound_port.c
index 70c71215..1029fc3d 100644
--- a/pjmedia/src/pjmedia/sound_port.c
+++ b/pjmedia/src/pjmedia/sound_port.c
@@ -563,7 +563,10 @@ PJ_DEF(pj_status_t) pjmedia_snd_port_set_ec( pjmedia_snd_port *snd_port,
 	    //since actual input latency should be zero.
 	    //delay_ms = (si.rec_latency + si.play_latency) * 1000 /
 	    //	   snd_port->clock_rate;
-	    delay_ms = prm.output_latency_ms;
+	    /* Set EC latency to 3/4 of output latency to reduce the
+	     * possibility of missing/late reference frame.
+	     */
+	    delay_ms = prm.output_latency_ms * 3/4;
 	    status = pjmedia_echo_create2(pool, snd_port->clock_rate, 
 					  snd_port->channel_count,
 					  snd_port->samples_per_frame,