diff --git a/sflphone-common/src/audio/audiortp.cpp b/sflphone-common/src/audio/audiortp.cpp
index d712b9ac900a210f4a671acb7501764d0a214554..0de4e82252778aad1d25d01d05ab8914b0b4ad85 100644
--- a/sflphone-common/src/audio/audiortp.cpp
+++ b/sflphone-common/src/audio/audiortp.cpp
@@ -410,7 +410,7 @@ AudioRtpRTX::sendSessionFromMic(int timestamp)
 
     } else {
 
-        int nbSamplesMax = 128;
+        int nbSamplesMax = 512;
         // no resampling required
         compSize = _audiocodec->codecEncode( micDataEncoded, micData, nbSample*sizeof(int16));
 
diff --git a/sflphone-common/src/audio/codecs/celtcodec.cpp b/sflphone-common/src/audio/codecs/celtcodec.cpp
index 21f0cc44ba8efc61d082b53eb4176317af65f250..6be8d1553dcbb89aea54ed3f2f5a7884f53ad6d6 100644
--- a/sflphone-common/src/audio/codecs/celtcodec.cpp
+++ b/sflphone-common/src/audio/codecs/celtcodec.cpp
@@ -87,7 +87,7 @@ class Celt : public AudioCodec{
         virtual int codecEncode (unsigned char *dst, short *src, unsigned int size) 
         {
             int len = 0;
-            len = celt_encode(enc, (celt_int16_t *)src, (celt_int16_t *)src, dst, 128);
+            len = celt_encode(enc, (celt_int16_t *)src, (celt_int16_t *)src, dst, 512);
             // returns the number of bytes writen
             return len;
         }