diff --git a/inc/rk_mpi.h b/inc/rk_mpi.h
index ce26e731..55ebb064 100644
--- a/inc/rk_mpi.h
+++ b/inc/rk_mpi.h
@@ -139,12 +139,30 @@ typedef struct MppEncConfig_t {
     RK_S32  trans8x8_en;
 } MppEncConfig;
 
+/*
+ * mpp main work function set
+ * size     : MppApi structure size
+ * version  : Mpp svn revision
+ *
+ * decode   : both send video stream packet to decoder and get video frame from
+ *            decoder at the same time.
+ * decode_put_packet: send video stream packet to decoder only, async interface
+ * decode_get_frame : get video frame from decoder only, async interface
+ *
+ * encode   : both send video frame to encoder and get encoded video stream from
+ *            encoder at the same time.
+ * encode_put_frame : send video frame to encoder only, async interface
+ * encode_get_packet: get encoded video packet from encoder only, async interface
+ *
+ * reset    : discard all packet and frame, reset all component,
+ *            for both decoder and encoder
+ * control  : control function for mpp property setting
+ * config   : config function for encoder, not implement yet.
+ */
 typedef struct MppApi_t {
     RK_U32  size;
     RK_U32  version;
 
-    MPP_RET (*config)(MppCtx ctx, MppEncConfig cfg);
-
     // sync interface
     MPP_RET (*decode)(MppCtx ctx, MppPacket packet, MppFrame *frame);
     MPP_RET (*encode)(MppCtx ctx, MppFrame frame, MppPacket *packet);
@@ -156,8 +174,9 @@ typedef struct MppApi_t {
     MPP_RET (*encode_put_frame)(MppCtx ctx, MppFrame frame);
     MPP_RET (*encode_get_packet)(MppCtx ctx, MppPacket *packet);
 
-    MPP_RET (*flush)(MppCtx ctx);
+    MPP_RET (*reset)(MppCtx ctx);
     MPP_RET (*control)(MppCtx ctx, MpiCmd cmd, MppParam param);
+    MPP_RET (*config)(MppCtx ctx, MppEncConfig cfg);
 
     RK_U32 reserv[16];
 } MppApi;
@@ -168,7 +187,13 @@ extern "C" {
 #endif
 
 /*
- * mpp interface
+ * mpp interface work flow
+ *
+ * 1. mpp_create : Create empty context structure and mpi function pointers.
+ * 2. mpp_init   : Call after mpp_create to setup mpp type and video format.
+ *                 This function will call internal context init function.
+ * 3. Use functions in MppApi to access mpp services.
+ * 4. mpp_destory: Destroy mpp context and free both context and mpi structure
  */
 MPP_RET mpp_create(MppCtx *ctx, MppApi **mpi);
 MPP_RET mpp_init(MppCtx ctx, MppCtxType type, MppCodingType coding);
diff --git a/mpp/codec/dec/h264/h264d_sei.c b/mpp/codec/dec/h264/h264d_sei.c
index 6a772fc5..6250334d 100644
--- a/mpp/codec/dec/h264/h264d_sei.c
+++ b/mpp/codec/dec/h264/h264d_sei.c
@@ -29,7 +29,7 @@
 
 #ifndef _WIN32
 #include <ctype.h>
-char *strupr(char *str)
+char *_strupr(char *str)
 {
 	char *orign=str;
 	for (; *str != '\0'; str++) {
@@ -86,7 +86,7 @@ static MPP_RET interpret_user_data_unregistered_info(RK_U8 *payload, RK_S32 size
 	}
 #endif
 
-	sei_msg->user_data_DivX_flag = strstr(strupr((char *)&payload[16]), "DIVX") ? 1 : 0;
+	sei_msg->user_data_DivX_flag = strstr(_strupr((char *)&payload[16]), "DIVX") ? 1 : 0;
 	if (sei_msg->user_data_DivX_flag) {
 		H264D_ERR("DivX is not supported. \n");
 		sei_msg->p_Dec->err_ctx.err_flag |= VPU_FRAME_ERR_UNSUPPORT;
@@ -217,7 +217,7 @@ static MPP_RET interpret_mvc_scalable_nesting_info(RK_U8 *payload, RK_S32 size,
         READ_BITS(p_strm, 3, &sei_op_temporal_id, "sei_op_temporal_id");
     }
 
-    p_bitctx->used_bits = p_strm->used_bits;    
+    p_bitctx->used_bits = p_strm->used_bits;
     return ret = MPP_OK;
 __BITREAD_ERR:
     ret = p_bitctx->ret;
@@ -404,7 +404,7 @@ MPP_RET process_sei(H264_SLICE_t *currSlice)
         sei_msg->payload_size += tmp_byte;   // this is the last byte
 
         //--- read sei info
-        FUN_CHECK(ret = parserSEI(currSlice, p_bitctx, sei_msg, p_bitctx->data_));		
+        FUN_CHECK(ret = parserSEI(currSlice, p_bitctx, sei_msg, p_bitctx->data_));
         //--- set offset to read next sei nal
         if (SEI_MVC_SCALABLE_NESTING == sei_msg->type) {
             sei_msg->payload_size = ((p_bitctx->used_bits + 0x07) >> 3);
diff --git a/mpp/legacy/vpu_api_legacy.cpp b/mpp/legacy/vpu_api_legacy.cpp
index b572b6ba..34a0a117 100644
--- a/mpp/legacy/vpu_api_legacy.cpp
+++ b/mpp/legacy/vpu_api_legacy.cpp
@@ -85,8 +85,8 @@ RK_S32 VpuApi::flush(VpuCodecContext *ctx)
 {
     (void)ctx;
     mpp_log_f("in\n");
-    if (mpi && mpi->flush) {
-        mpi->flush(mpp_ctx);
+    if (mpi && mpi->reset) {
+        mpi->reset(mpp_ctx);
     }
     mpp_log_f("ok\n");
     return 0;
diff --git a/mpp/mpi.cpp b/mpp/mpi.cpp
index 11d275a9..14dd5442 100644
--- a/mpp/mpi.cpp
+++ b/mpp/mpi.cpp
@@ -126,7 +126,7 @@ static MPP_RET mpi_encode_get_packet(MppCtx ctx, MppPacket *packet)
     return ret;
 }
 
-static MPP_RET mpi_flush(MppCtx ctx)
+static MPP_RET mpi_reset(MppCtx ctx)
 {
     MpiImpl *p = (MpiImpl *)ctx;
     MPP_RET ret = MPP_OK;
@@ -150,15 +150,15 @@ static MPP_RET mpi_control(MppCtx ctx, MpiCmd cmd, MppParam param)
 static MppApi mpp_api = {
     sizeof(mpp_api),
     0,
-    mpi_config,
     mpi_decode,
     mpi_encode,
     mpi_decode_put_packet,
     mpi_decode_get_frame,
     mpi_encode_put_frame,
     mpi_encode_get_packet,
-    mpi_flush,
+    mpi_reset,
     mpi_control,
+    mpi_config,
     {0},
 };
 
@@ -202,7 +202,6 @@ MPP_RET mpp_create(MppCtx *ctx, MppApi **mpi)
     return MPP_OK;
 }
 
-
 MPP_RET mpp_init(MppCtx ctx, MppCtxType type, MppCodingType coding)
 {
     MpiImpl *p = (MpiImpl*)ctx;
diff --git a/test/mpi_test.c b/test/mpi_test.c
index 92a7f5c9..708d9438 100644
--- a/test/mpi_test.c
+++ b/test/mpi_test.c
@@ -166,9 +166,9 @@ int mpi_test()
     }
 
 
-    ret = mpi->flush(ctx);
+    ret = mpi->reset(ctx);
     if (MPP_OK != ret) {
-        mpp_err("mpi->flush failed\n");
+        mpp_err("mpi->reset failed\n");
         goto MPP_TEST_FAILED;
     }
 
@@ -247,9 +247,9 @@ int mpi_test()
     }
 
 
-    ret = mpi->flush(ctx);
+    ret = mpi->reset(ctx);
     if (MPP_OK != ret) {
-        mpp_err("mpi->flush failed\n");
+        mpp_err("mpi->reset failed\n");
         goto MPP_TEST_FAILED;
     }