diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index adb49e4525..593188c824 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -427,7 +427,8 @@ static void av_always_inline horizontal_fill(TiffContext *s,
             uint8_t shift = is_dng ? 0 : 16 - bpp;
             GetBitContext gb;
 
-            init_get_bits8(&gb, src, width);
+            int ret = init_get_bits8(&gb, src, width);
+            av_assert1(ret >= 0);
             for (int i = 0; i < s->width; i++) {
                 dst16[i] = get_bits(&gb, bpp) << shift;
             }