libhb: reset some fields before sending an AVFrame to be encoded.

libhb/encavcodec.c

@@ -1068,6 +1068,7 @@ static void Encode( hb_work_object_t *w, hb_buffer_t **buf_in,
     // This will consume the hb_buffer_t and make it NULL
     hb_video_buffer_to_avframe(&frame, buf_in);
     frame.pts = pv->frameno_in++;
+    frame.duration = 0;
 
     // For constant quality, setting the quality in AVCodecContext
     // doesn't do the trick.  It must be set in the AVFrame.
@@ -1076,7 +1077,12 @@ static void Encode( hb_work_object_t *w, hb_buffer_t **buf_in,
     if (key_frame)
     {
         frame.pict_type = AV_PICTURE_TYPE_I;
-        frame.flags |= AV_FRAME_FLAG_KEY;
+        frame.flags = AV_FRAME_FLAG_KEY;
+    }
+    else
+    {
+        frame.pict_type = AV_PICTURE_TYPE_NONE;
+        frame.flags = 0;
     }
 
     // Encode