diff --git a/linphone/coreapi/linphonecore.c b/linphone/coreapi/linphonecore.c
index 4e59a56808a27253e914d730d1151f30fc5350dd..2fcb0862a199101517d2c86698333632ffa6cc95 100644
--- a/linphone/coreapi/linphonecore.c
+++ b/linphone/coreapi/linphonecore.c
@@ -1565,6 +1565,7 @@ static void post_configure_audio_streams(LinphoneCore *lc){
float speed=lp_config_get_float(lc->config,"sound","el_speed",-1);
float thres=lp_config_get_float(lc->config,"sound","el_thres",-1);
float force=lp_config_get_float(lc->config,"sound","el_force",-1);
+ int sustain=lp_config_get_int(lc->config,"sound","el_sustain",-1);
float gain=lp_config_get_float(lc->config,"sound","mic_gain",-1);
MSFilter *f=NULL;
if (st->el_type==ELControlMic){
@@ -1583,6 +1584,8 @@ static void post_configure_audio_streams(LinphoneCore *lc){
ms_filter_call_method(f,MS_VOLUME_SET_EA_THRESHOLD,&thres);
if (force!=-1)
ms_filter_call_method(f,MS_VOLUME_SET_EA_FORCE,&force);
+ if (sustain!=-1)
+ ms_filter_call_method(f,MS_VOLUME_SET_EA_SUSTAIN,&sustain);
if (gain!=-1)
audio_stream_set_mic_gain(st,gain);
}
diff --git a/linphone/mediastreamer2/include/mediastreamer2/msvolume.h b/linphone/mediastreamer2/include/mediastreamer2/msvolume.h
index 7fc46cdcdbac6104fb2edd6b8eba599d6995956f..052e3d1b99eeb325244c0a2cb9ab50ebee9a2e10 100644
--- a/linphone/mediastreamer2/include/mediastreamer2/msvolume.h
+++ b/linphone/mediastreamer2/include/mediastreamer2/msvolume.h
@@ -54,6 +54,9 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#define MS_VOLUME_SET_NOISE_GATE_THRESHOLD MS_FILTER_METHOD(MS_VOLUME_ID,10,float)
+#define MS_VOLUME_SET_EA_SUSTAIN MS_FILTER_METHOD(MS_VOLUME_ID,11,int)
+
+
extern MSFilterDesc ms_volume_desc;
#endif
diff --git a/linphone/mediastreamer2/src/msvolume.c b/linphone/mediastreamer2/src/msvolume.c
index ae642bde08a5ae0fcb1e81827cfe87f1be4b6069..1deb38b58d06ef33cd5f37d7241653c2dc339420 100644
--- a/linphone/mediastreamer2/src/msvolume.c
+++ b/linphone/mediastreamer2/src/msvolume.c
@@ -22,6 +22,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#endif
#include "mediastreamer2/msvolume.h"
+#include "mediastreamer2/msticker.h"
#include <math.h>
#ifdef HAVE_SPEEXDSP
@@ -44,6 +45,9 @@ typedef struct Volume{
float thres;
float force;
float target_gain; /*the target gain choosed by echo limiter and noise gate*/
+ float last_peer_en;
+ int sustain_time; /* time in ms for which echo limiter remains active after resuming from speech to silence.*/
+ uint64_t sustain_start;
MSFilter *peer;
#ifdef HAVE_SPEEXDSP
SpeexPreprocessState *speex_pp;
@@ -69,6 +73,9 @@ static void volume_init(MSFilter *f){
v->thres=noise_thres;
v->force=en_weight;
v->peer=NULL;
+ v->last_peer_en=0;
+ v->sustain_time=200;
+ v->sustain_start=0;
v->agc_enabled=FALSE;
v->buffer=ms_bufferizer_new();
v->sample_rate=8000;
@@ -126,7 +133,15 @@ static inline float compute_gain(float static_gain, float energy, float weight){
return ret;
}
-static void volume_echo_avoider_process(Volume *v){
+/*
+The principle of this algorithm is that we apply a gain to the input signal which is opposite to the
+energy measured by the peer MSVolume.
+For example if some noise is played by the speaker, then the signal captured by the microphone will be lowered.
+The gain changes smoothly when the peer energy is decreasing, but is immediately changed when the peer energy is
+increasing.
+*/
+
+static void volume_echo_avoider_process(Volume *v, uint64_t curtime){
float peer_e;
float gain;
ms_filter_call_method(v->peer,MS_VOLUME_GET_LINEAR,&peer_e);
@@ -135,9 +150,12 @@ static void volume_echo_avoider_process(Volume *v){
if (peer_e>v->thres){
/*lower our output*/
gain=compute_gain(v->static_gain,peer_e,v->force);
+ if (peer_e>v->last_peer_en)
+ v->gain=gain;
}else {
- gain=v->static_gain;
+ v->sustain_start=curtime;
v->ea_active=FALSE;
+ gain=v->gain;
}
}else{
int peer_active=FALSE;
@@ -148,9 +166,15 @@ static void volume_echo_avoider_process(Volume *v){
v->ea_active=TRUE;
v->gain=gain;
}else {
- gain=v->static_gain;
+ if (curtime!=0 && (curtime-v->sustain_start)<v->sustain_time){
+ gain=v->gain;
+ }else{/*restore normal gain*/
+ gain=v->static_gain;
+ v->sustain_start=0;
+ }
}
}
+ v->last_peer_en=peer_e;
v->target_gain=gain;
ms_message("ea_active=%i, peer_e=%f gain=%f gain_k=%f force=%f",v->ea_active,peer_e,v->gain, v->gain_k,v->force);
}
@@ -225,6 +249,12 @@ static int volume_set_ea_force(MSFilter *f, void*arg){
return 0;
}
+static int volume_set_ea_sustain(MSFilter *f, void *arg){
+ Volume *v=(Volume*)f->data;
+ v->sustain_time=*(int*)arg;
+ return 0;
+}
+
static int volume_enable_noise_gate(MSFilter *f, void *arg){
Volume *v=(Volume*)f->data;
v->noise_gate_enabled=*(int*)arg;
@@ -308,7 +338,7 @@ static void volume_process(MSFilter *f){
volume_agc_process(v,om);
if (v->peer){
- volume_echo_avoider_process(v);
+ volume_echo_avoider_process(v,f->ticker->time);
}else v->target_gain=v->static_gain;
if (v->noise_gate_enabled)
@@ -321,7 +351,7 @@ static void volume_process(MSFilter *f){
while((m=ms_queue_get(f->inputs[0]))!=NULL){
en=update_energy((int16_t*)m->b_rptr,(m->b_wptr-m->b_rptr)/2,en);
if (v->peer){
- volume_echo_avoider_process(v);
+ volume_echo_avoider_process(v,f->ticker->time);
}else v->target_gain=v->static_gain;
if (v->noise_gate_enabled)
@@ -342,6 +372,7 @@ static MSFilterMethod methods[]={
{ MS_VOLUME_SET_EA_THRESHOLD , volume_set_ea_threshold },
{ MS_VOLUME_SET_EA_SPEED , volume_set_ea_speed },
{ MS_VOLUME_SET_EA_FORCE , volume_set_ea_force },
+ { MS_VOLUME_SET_EA_SUSTAIN, volume_set_ea_sustain },
{ MS_FILTER_SET_SAMPLE_RATE, volume_set_sample_rate },
{ MS_VOLUME_ENABLE_AGC , volume_set_agc },
{ MS_VOLUME_ENABLE_NOISE_GATE, volume_enable_noise_gate},