FP2-1366: Fix the sip call stop

Change-Id: I1b2f6fe28378c14530c19204962e6d6c5016ca22
diff --git a/src/jni/rtp/AudioGroup.cpp b/src/jni/rtp/AudioGroup.cpp
index 5dce123..15a72be 100644
--- a/src/jni/rtp/AudioGroup.cpp
+++ b/src/jni/rtp/AudioGroup.cpp
@@ -996,7 +996,7 @@
     if (!group) {
         int mode = env->GetIntField(thiz, gMode);
         group = new AudioGroup;
-        if (!group->set(8000, 256) || !group->setMode(mode)) {
+        if (!group->set(8000, 320) || !group->setMode(mode)) {
             jniThrowException(env, "java/lang/IllegalStateException",
                 "cannot initialize audio group");
             goto error;