diff --git a/libavcodec/shorten.c b/libavcodec/shorten.c
index c36bb9ee2b4d39fed1835ee99680db937f0659a8..45bc635cd0d16920605f65ef561262c81a375cb0 100644
--- a/libavcodec/shorten.c
+++ b/libavcodec/shorten.c
@@ -190,7 +190,7 @@ static int init_offset(ShortenContext *s)
     switch (s->internal_ftype)
     {
         case TYPE_U8:
-            s->avctx->sample_fmt = AV_SAMPLE_FMT_U8;
+            s->avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
             mean = 0x80;
             break;
         case TYPE_S16HL: