diff --git a/mpp/codec/mpp_enc_impl.cpp b/mpp/codec/mpp_enc_impl.cpp
index 158ace4b..fe125b7e 100644
--- a/mpp/codec/mpp_enc_impl.cpp
+++ b/mpp/codec/mpp_enc_impl.cpp
@@ -186,10 +186,12 @@ static MPP_RET release_task_in_port(MppPort port)
     MppTask mpp_task;
 
     do {
-        ret = mpp_port_dequeue(port, &mpp_task);
+        ret = mpp_port_poll(port, MPP_POLL_NON_BLOCK);
         if (ret)
             break;
 
+        mpp_port_dequeue(port, &mpp_task);
+        mpp_assert(mpp_task);
         if (mpp_task) {
             packet = NULL;
             frame = NULL;
diff --git a/mpp/mpp.cpp b/mpp/mpp.cpp
index 55ad5289..2f5ce936 100644
--- a/mpp/mpp.cpp
+++ b/mpp/mpp.cpp
@@ -459,6 +459,12 @@ MPP_RET Mpp::put_frame(MppFrame frame)
     }
 
     mpp_assert(mInputTask);
+    if (mInputTask) {
+        MppFrame frm_out = NULL;
+
+        mpp_task_meta_get_frame(mInputTask, KEY_INPUT_FRAME, &frm_out);
+        mpp_assert(frm_out == frame);
+    }
 
 RET:
     mpp_stopwatch_record(stopwatch, "put_frame finish");