diff --git a/mpp/base/mpp_buf_slot.cpp b/mpp/base/mpp_buf_slot.cpp
index 79feafea..e693ce1d 100644
--- a/mpp/base/mpp_buf_slot.cpp
+++ b/mpp/base/mpp_buf_slot.cpp
@@ -333,6 +333,7 @@ static void generate_info_set(MppBufSlotsImpl *impl, MppFrame frame, RK_U32 forc
             mpp_err("dec out fmt is no support");
         } break;
         }
+        mpp_frame_set_fbc_size(frame, size);
     } else {
         size *= impl->numerator;
         size /= impl->denominator;