diff --git a/libavcodec/aac_adtstoasc_bsf.c b/libavcodec/aac_adtstoasc_bsf.c
index 1067160559..e116b1d85b 100644
--- a/libavcodec/aac_adtstoasc_bsf.c
+++ b/libavcodec/aac_adtstoasc_bsf.c
@@ -49,14 +49,14 @@ static int aac_adtstoasc_filter(AVBSFContext *bsfc, AVPacket *out)
     if (ret < 0)
         return ret;
 
+    if (bsfc->par_in->extradata && in->size >= 2 && (AV_RB16(in->data) >> 4) != 0xfff)
+        goto finish;
+
     if (in->size < AAC_ADTS_HEADER_SIZE)
         goto packet_too_small;
 
     init_get_bits(&gb, in->data, AAC_ADTS_HEADER_SIZE * 8);
 
-    if (bsfc->par_in->extradata && show_bits(&gb, 12) != 0xfff)
-        goto finish;
-
     if (avpriv_aac_parse_header(&gb, &hdr) < 0) {
         av_log(bsfc, AV_LOG_ERROR, "Error parsing ADTS frame header!\n");
         ret = AVERROR_INVALIDDATA;