diff --git a/sflphone-common/src/audio/codecs/alaw.cpp b/sflphone-common/src/audio/codecs/alaw.cpp
index 807d518bab0880b579c09f9ba5505f607d27af54..8949836b6db847d447cfb3abb022914cfc5cb816 100644
--- a/sflphone-common/src/audio/codecs/alaw.cpp
+++ b/sflphone-common/src/audio/codecs/alaw.cpp
@@ -28,6 +28,7 @@ public:
  	: AudioCodec(payload, "PCMA")
 	{
   		_clockRate = 8000;
+                _frameSize = 160; // 20 ms at 8kHz
   		_channel   = 1;
 		_bitrate = 64;
 		_bandwidth = 80;
diff --git a/sflphone-common/src/audio/codecs/celtcodec.cpp b/sflphone-common/src/audio/codecs/celtcodec.cpp
index f9408d2bd4338240de1517a39db8d2ff389db37e..feb3f61d0baca9a3563d69b2675ff295828892b1 100644
--- a/sflphone-common/src/audio/codecs/celtcodec.cpp
+++ b/sflphone-common/src/audio/codecs/celtcodec.cpp
@@ -30,7 +30,7 @@ class Celt : public AudioCodec{
               _celt_frame_size(128)
     {
         _clockRate = 44100;
-        _frameSize = 512;
+        _frameSize = 512; // fixed frameSize, TODO: support 64 to 512 frame size
         _channel = 1;
         _bitrate = 0;
         _bandwidth = 0;
diff --git a/sflphone-common/src/audio/codecs/speexcodec_nb.cpp b/sflphone-common/src/audio/codecs/speexcodec_nb.cpp
index 72b3c36d0dadff319f236358b05be1e389f49ca4..6807fcfcfb7c5a5c1e59001cb671ec19d8a48242 100644
--- a/sflphone-common/src/audio/codecs/speexcodec_nb.cpp
+++ b/sflphone-common/src/audio/codecs/speexcodec_nb.cpp
@@ -36,6 +36,7 @@ class Speex : public AudioCodec{
             _preprocess_state()
     {
         _clockRate = 8000;
+        _frameSize = 160; // 20 ms at 8kHz
         _channel = 1;
         _bitrate = 0;
         _bandwidth = 0; 
diff --git a/sflphone-common/src/audio/codecs/speexcodec_wb.cpp b/sflphone-common/src/audio/codecs/speexcodec_wb.cpp
index e86b3d724ef7b21040f7da61af96461fbd899685..81d27bbcb0eebee7d7a75687bf82c0a8e410b9b6 100644
--- a/sflphone-common/src/audio/codecs/speexcodec_wb.cpp
+++ b/sflphone-common/src/audio/codecs/speexcodec_wb.cpp
@@ -36,6 +36,7 @@ class Speex : public AudioCodec{
             _preprocess_state()
     {
         _clockRate = 16000;
+        _frameSize = 320; // 20 ms at 16 kHz
         _channel = 1;
         _bitrate = 0;
         _bandwidth = 0; 
diff --git a/sflphone-common/src/audio/codecs/ulaw.cpp b/sflphone-common/src/audio/codecs/ulaw.cpp
index 6d44bff13c0ff27272a39d45e0c913fdb985619a..a7be89936a14281abd8a06fa95e0997c7844ee22 100644
--- a/sflphone-common/src/audio/codecs/ulaw.cpp
+++ b/sflphone-common/src/audio/codecs/ulaw.cpp
@@ -30,6 +30,7 @@ public:
  	: AudioCodec(payload, "PCMU")
 	{
   		_clockRate = 8000;
+                _frameSize = 160; // 20 ms at 8kHz
   		_channel   = 1;
 		_bitrate =  64; 
 		_bandwidth = 80;