diff --git a/sat/plugins/plugin_xep_0047.py b/sat/plugins/plugin_xep_0047.py
index 5cea0b2c..1ef5699f 100644
--- a/sat/plugins/plugin_xep_0047.py
+++ b/sat/plugins/plugin_xep_0047.py
@@ -327,7 +327,8 @@ class XEP_0047(object):
         """
         session_data["timer"].reset(TIMEOUT)
 
-        buffer_ = session_data["stream_object"].read(session_data["block_size"])
+        # FIXME: producer/consumer mechanism is not used properly here
+        buffer_ = session_data["stream_object"].file_obj.read(session_data["block_size"])
         if buffer_:
             next_iq_elt = client.IQ()
             next_iq_elt["from"] = session_data["local_jid"].full()
@@ -336,7 +337,7 @@ class XEP_0047(object):
             seq = session_data["seq"] = (session_data["seq"] + 1) % 65535
             data_elt["seq"] = str(seq)
             data_elt["sid"] = session_data["id"]
-            data_elt.addContent(base64.b64encode(buffer_))
+            data_elt.addContent(base64.b64encode(buffer_).decode())
             args = [session_data, client]
             d = next_iq_elt.send()
             d.addCallbacks(self._IQDataStreamCb, self._IQDataStreamEb, args, None, args)