diff --git a/libavcodec/aacpsy.c b/libavcodec/aacpsy.c
index 4c5ab2c9d5..933369e445 100644
--- a/libavcodec/aacpsy.c
+++ b/libavcodec/aacpsy.c
@@ -267,7 +267,7 @@ static av_cold void lame_window_init(AacPsyContext *ctx, AVCodecContext *avctx)
         AacPsyChannel *pch = &ctx->ch[i];
 
         if (avctx->flags & AV_CODEC_FLAG_QSCALE)
-            pch->attack_threshold = psy_vbr_map[avctx->global_quality / FF_QP2LAMBDA].st_lrm;
+            pch->attack_threshold = psy_vbr_map[av_clip(avctx->global_quality / FF_QP2LAMBDA, 0, 10)].st_lrm;
         else
             pch->attack_threshold = lame_calc_attack_threshold(avctx->bit_rate / avctx->ch_layout.nb_channels / 1000);