diff --git a/libavcodec/cinepak.c b/libavcodec/cinepak.c
index d26c505222..a5132ddbc0 100644
--- a/libavcodec/cinepak.c
+++ b/libavcodec/cinepak.c
@@ -354,7 +354,7 @@ static int cinepak_predecode_check (CinepakContext *s)
         return AVERROR_INVALIDDATA;
 
     if (num_strips) {
-        uint8_t *data = s->data + 10 + s->sega_film_skip_bytes;
+        const uint8_t *data = s->data + 10 + s->sega_film_skip_bytes;
         int strip_size = AV_RB24 (data + 1);
         if (strip_size < 12 || strip_size > encoded_buf_size)
             return AVERROR_INVALIDDATA;