diff --git a/libavcodec/sp5xdec.c b/libavcodec/sp5xdec.c
index 04ddf09fff..d3efa65674 100644
--- a/libavcodec/sp5xdec.c
+++ b/libavcodec/sp5xdec.c
@@ -90,7 +90,7 @@ static int sp5x_decode_frame(AVCodecContext *avctx,
 
     av_free(recoded);
 
-    return i;
+    return i < 0 ? i : avpkt->size;
 }
 
 #if CONFIG_SP5X_DECODER