diff --git a/libavcodec/wavpackenc.c b/libavcodec/wavpackenc.c
index 3d2d45360d..9271e87990 100644
--- a/libavcodec/wavpackenc.c
+++ b/libavcodec/wavpackenc.c
@@ -2824,7 +2824,7 @@ static void fill_buffer(WavPackEncodeContext *s,
 
     switch (s->avctx->sample_fmt) {
     case AV_SAMPLE_FMT_U8P:
-        COPY_SAMPLES(int8_t, 0x80, 0);
+        COPY_SAMPLES(uint8_t, 0x80, 0);
         break;
     case AV_SAMPLE_FMT_S16P:
         COPY_SAMPLES(int16_t, 0, 0);