diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index 950284946e..8b203218d1 100644
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -770,7 +770,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
                 return AVERROR_INVALIDDATA;
             }
         }
-        for (n = nb_samples >> (1 - st); n > 0; n--) {
+        for (n = (nb_samples >> (1 - st)) - 1; n > 0; n--) {
             int v = bytestream2_get_byteu(&gb);
             *samples++ = adpcm_ima_expand_nibble(&c->status[0 ], v >> 4  , 3);
             *samples++ = adpcm_ima_expand_nibble(&c->status[st], v & 0x0F, 3);