diff --git a/libvideoeditor/vss/inc/M4VSS3GPP_ErrorCodes.h b/libvideoeditor/vss/inc/M4VSS3GPP_ErrorCodes.h
index 4bf2e84..7c500da 100755
--- a/libvideoeditor/vss/inc/M4VSS3GPP_ErrorCodes.h
+++ b/libvideoeditor/vss/inc/M4VSS3GPP_ErrorCodes.h
@@ -273,6 +273,9 @@
 /**
  * Output file must be 3GPP or MP3 */
 #define M4VSS3GPP_ERR_OUTPUT_FILE_TYPE_ERROR         M4OSA_ERR_CREATE( M4_ERR, M4VSS3GPP, 0x0117)
+/**
+ * Can not find a valid video frame */
+#define M4VSS3GPP_ERR_NO_VALID_VID_FRAME         M4OSA_ERR_CREATE( M4_ERR, M4VSS3GPP, 0x0118)
 
 #endif /* __M4VSS3GPP_ErrorCodes_H__ */
 
diff --git a/libvideoeditor/vss/src/M4VSS3GPP_EditVideo.c b/libvideoeditor/vss/src/M4VSS3GPP_EditVideo.c
index 59d57e5..f19f412 100755
--- a/libvideoeditor/vss/src/M4VSS3GPP_EditVideo.c
+++ b/libvideoeditor/vss/src/M4VSS3GPP_EditVideo.c
@@ -20,6 +20,8 @@
  * @note
  ******************************************************************************
  */
+#undef M4OSA_TRACE_LEVEL
+#define M4OSA_TRACE_LEVEL 1
 
 /****************/
 /*** Includes ***/
@@ -491,7 +493,6 @@
                     }
 
 #endif                                   //M4VSS_SUPPORT_OMX_CODECS
-
                 }
                 else if( M4NO_ERROR != err ) /**< ...or an encoder error */
                 {
@@ -655,7 +656,6 @@
                     }
 
 #endif //M4VSS_SUPPORT_OMX_CODECS
-
                 }
                 else if( M4NO_ERROR != err ) /**< ...or an encoder error */
                 {
@@ -1198,7 +1198,7 @@
         if ((pC->pC1->isRenderDup == M4OSA_TRUE) ||
              (M4WAR_VIDEORENDERER_NO_NEW_FRAME == err)) {
             pTmp = pC->yuv1;
-            if (pC->pC1->lastDecodedPlane != M4NO_ERROR) {
+            if (pC->pC1->lastDecodedPlane != M4OSA_NULL) {
                 /* Copy last decoded plane to output plane */
                 memcpy((void *)pTmp[0].pac_data,
                     (void *)pC->pC1->lastDecodedPlane[0].pac_data,
@@ -1209,6 +1209,12 @@
                 memcpy((void *)pTmp[2].pac_data,
                     (void *)pC->pC1->lastDecodedPlane[2].pac_data,
                     (pTmp[2].u_height * pTmp[2].u_width));
+            } else {
+                err = M4VSS3GPP_ERR_NO_VALID_VID_FRAME;
+                M4OSA_TRACE1_3("Can not find an input frame. Set error 0x%x in %s (%d)",
+                   err, __FILE__, __LINE__);
+                pC->ewc.VppError = err;
+                return M4NO_ERROR;
             }
             pC->pC1->lastDecodedPlane = pTmp;
         }
@@ -1238,7 +1244,7 @@
         if ((pC->pC2->isRenderDup == M4OSA_TRUE) ||
              (M4WAR_VIDEORENDERER_NO_NEW_FRAME == err)) {
             pTmp = pC->yuv2;
-            if (pC->pC2->lastDecodedPlane != M4NO_ERROR) {
+            if (pC->pC2->lastDecodedPlane != M4OSA_NULL) {
                 /* Copy last decoded plane to output plane */
                 memcpy((void *)pTmp[0].pac_data,
                     (void *)pC->pC2->lastDecodedPlane[0].pac_data,
@@ -1249,6 +1255,12 @@
                 memcpy((void *)pTmp[2].pac_data,
                     (void *)pC->pC2->lastDecodedPlane[2].pac_data,
                     (pTmp[2].u_height * pTmp[2].u_width));
+            } else {
+                err = M4VSS3GPP_ERR_NO_VALID_VID_FRAME;
+                M4OSA_TRACE1_3("Can not find an input frame. Set error 0x%x in %s (%d)",
+                   err, __FILE__, __LINE__);
+                pC->ewc.VppError = err;
+                return M4NO_ERROR;
             }
             pC->pC2->lastDecodedPlane = pTmp;
         }
@@ -1505,17 +1517,29 @@
             if (M4OSA_NULL != pC->pC1->m_pPreResizeFrame) {
                 /**
                 * Copy last decoded plane to output plane */
-                memcpy((void *)pC->pC1->m_pPreResizeFrame[0].pac_data,
-                 (void *)pC->pC1->lastDecodedPlane[0].pac_data,
-                 (pC->pC1->m_pPreResizeFrame[0].u_height * pC->pC1->m_pPreResizeFrame[0].u_width));
+                if (pC->pC1->lastDecodedPlane != M4OSA_NULL) {
 
-                memcpy((void *)pC->pC1->m_pPreResizeFrame[1].pac_data,
-                 (void *)pC->pC1->lastDecodedPlane[1].pac_data,
-                 (pC->pC1->m_pPreResizeFrame[1].u_height * pC->pC1->m_pPreResizeFrame[1].u_width));
+                    memcpy((void *)pC->pC1->m_pPreResizeFrame[0].pac_data,
+                        (void *)pC->pC1->lastDecodedPlane[0].pac_data,
+                        (pC->pC1->m_pPreResizeFrame[0].u_height * \
+                         pC->pC1->m_pPreResizeFrame[0].u_width));
 
-                memcpy((void *)pC->pC1->m_pPreResizeFrame[2].pac_data,
-                 (void *)pC->pC1->lastDecodedPlane[2].pac_data,
-                 (pC->pC1->m_pPreResizeFrame[2].u_height * pC->pC1->m_pPreResizeFrame[2].u_width));
+                    memcpy((void *)pC->pC1->m_pPreResizeFrame[1].pac_data,
+                        (void *)pC->pC1->lastDecodedPlane[1].pac_data,
+                        (pC->pC1->m_pPreResizeFrame[1].u_height * \
+                         pC->pC1->m_pPreResizeFrame[1].u_width));
+
+                    memcpy((void *)pC->pC1->m_pPreResizeFrame[2].pac_data,
+                        (void *)pC->pC1->lastDecodedPlane[2].pac_data,
+                        (pC->pC1->m_pPreResizeFrame[2].u_height * \
+                         pC->pC1->m_pPreResizeFrame[2].u_width));
+                } else {
+                    err = M4VSS3GPP_ERR_NO_VALID_VID_FRAME;
+                    M4OSA_TRACE1_3("Can not find an input frame. Set error 0x%x in %s (%d)",
+                        err, __FILE__, __LINE__);
+                    pC->ewc.VppError = err;
+                    return M4NO_ERROR;
+                }
 
                 if(pC->nbActiveEffects > 0) {
                     /**
@@ -1587,17 +1611,26 @@
                 }
                 /**
                  * Copy last decoded plane to output plane */
-                memcpy((void *)pLastDecodedFrame[0].pac_data,
-                 (void *)pC->pC1->lastDecodedPlane[0].pac_data,
-                 (pLastDecodedFrame[0].u_height * pLastDecodedFrame[0].u_width));
+                if (pC->pC1->lastDecodedPlane != M4OSA_NULL &&
+                    pLastDecodedFrame != M4OSA_NULL) {
+                    memcpy((void *)pLastDecodedFrame[0].pac_data,
+                        (void *)pC->pC1->lastDecodedPlane[0].pac_data,
+                        (pLastDecodedFrame[0].u_height * pLastDecodedFrame[0].u_width));
 
-                memcpy((void *)pLastDecodedFrame[1].pac_data,
-                 (void *)pC->pC1->lastDecodedPlane[1].pac_data,
-                 (pLastDecodedFrame[1].u_height * pLastDecodedFrame[1].u_width));
+                    memcpy((void *)pLastDecodedFrame[1].pac_data,
+                        (void *)pC->pC1->lastDecodedPlane[1].pac_data,
+                        (pLastDecodedFrame[1].u_height * pLastDecodedFrame[1].u_width));
 
-                memcpy((void *)pLastDecodedFrame[2].pac_data,
-                 (void *)pC->pC1->lastDecodedPlane[2].pac_data,
-                 (pLastDecodedFrame[2].u_height * pLastDecodedFrame[2].u_width));
+                    memcpy((void *)pLastDecodedFrame[2].pac_data,
+                        (void *)pC->pC1->lastDecodedPlane[2].pac_data,
+                        (pLastDecodedFrame[2].u_height * pLastDecodedFrame[2].u_width));
+                } else {
+                    err = M4VSS3GPP_ERR_NO_VALID_VID_FRAME;
+                    M4OSA_TRACE1_3("Can not find an input frame. Set error 0x%x in %s (%d)",
+                        err, __FILE__, __LINE__);
+                    pC->ewc.VppError = err;
+                    return M4NO_ERROR;
+                }
 
                 pTmp = pPlaneOut;
                 /**
diff --git a/libvideoeditor/vss/stagefrightshells/inc/VideoEditorVideoDecoder_internal.h b/libvideoeditor/vss/stagefrightshells/inc/VideoEditorVideoDecoder_internal.h
index cca5ee9..6762643 100755
--- a/libvideoeditor/vss/stagefrightshells/inc/VideoEditorVideoDecoder_internal.h
+++ b/libvideoeditor/vss/stagefrightshells/inc/VideoEditorVideoDecoder_internal.h
@@ -115,6 +115,9 @@
     ARect                   mCropRect;  // These are obtained from kKeyCropRect.
     I420ColorConverter*     mI420ColorConverter;
 
+    // Time interval between two consequtive/neighboring video frames.
+    M4_MediaTime            mFrameIntervalMs;
+
 } VideoEditorVideoDecoder_Context;
 
 } //namespace android
diff --git a/libvideoeditor/vss/stagefrightshells/src/VideoEditorVideoDecoder.cpp b/libvideoeditor/vss/stagefrightshells/src/VideoEditorVideoDecoder.cpp
index aa26252..21d3c30 100755
--- a/libvideoeditor/vss/stagefrightshells/src/VideoEditorVideoDecoder.cpp
+++ b/libvideoeditor/vss/stagefrightshells/src/VideoEditorVideoDecoder.cpp
@@ -982,6 +982,11 @@
     pDecShellContext->mLastOutputCts     = -1;
     pDecShellContext->m_pDecBufferPool   = M4OSA_NULL;
 
+    // Calculate the interval between two video frames.
+    CHECK(pDecShellContext->m_pVideoStreamhandler->m_averageFrameRate > 0);
+    pDecShellContext->mFrameIntervalMs =
+            1000.0 / pDecShellContext->m_pVideoStreamhandler->m_averageFrameRate;
+
     /**
      * StageFright graph building
      */
@@ -1423,8 +1428,25 @@
         ALOGV("VideoEditorVideoDecoder_decode,decoded frametime = %lf,size = %d",
             (M4_MediaTime)lFrameTime, pDecoderBuffer->size() );
 
-        // If bJump is false, we need to save every decoded buffer
-        if (!bJump) {
+        /*
+         * We need to save a buffer if bJump == false to a queue. These
+         * buffers have a timestamp >= the target time, *pTime (for instance,
+         * the transition between two videos, or a trimming postion inside
+         * one video), since they are part of the transition clip or the
+         * trimmed video.
+         *
+         * If *pTime does not have the same value as any of the existing
+         * video frames, we would like to get the buffer right before *pTime
+         * and in the transcoding phrase, this video frame will be encoded
+         * as a key frame and becomes the first video frame for the transition or the
+         * trimmed video to be generated. This buffer must also be queued.
+         *
+         */
+        int64_t targetTimeMs =
+                pDecShellContext->m_lastDecodedCTS +
+                pDecShellContext->mFrameIntervalMs +
+                tolerance;
+        if (!bJump || targetTimeMs > *pTime) {
             lerr = copyBufferToQueue(pDecShellContext, pDecoderBuffer);
             if (lerr != M4NO_ERROR) {
                 goto VIDEOEDITOR_VideoDecode_cleanUP;
@@ -1432,14 +1454,6 @@
         }
     }
 
-    // If bJump is true, we only need to copy the last buffer
-    if (bJump) {
-        lerr = copyBufferToQueue(pDecShellContext, pDecoderBuffer);
-        if (lerr != M4NO_ERROR) {
-            goto VIDEOEDITOR_VideoDecode_cleanUP;
-        }
-    }
-
     pDecShellContext->mNbOutputFrames++;
     if ( 0 > pDecShellContext->mFirstOutputCts ) {
         pDecShellContext->mFirstOutputCts = *pTime;