diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index 00cb047374..47fd9b6a34 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -1052,7 +1052,8 @@ static int cbr_bit_allocation(AC3EncodeContext *s)
     int snr_offset, snr_incr;
 
     bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
-    av_assert2(bits_left >= 0);
+    if (bits_left < 0)
+        return AVERROR(EINVAL);
 
     snr_offset = s->coarse_snr_offset << 4;