avcodec/hevc: calculate checksum only if AV_EF_EXPLODE is set

This avoids a slowdown with the default of enabled CRC checks
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/hevc.c

@@ -2504,9 +2504,10 @@ static int hevc_decode_frame(AVCodecContext *avctx, void *data, int *got_output,
 
     /* verify the SEI checksum */
     if (avctx->err_recognition & AV_EF_CRCCHECK && s->is_decoded &&
+        avctx->err_recognition & AV_EF_EXPLODE &&
         s->is_md5) {
         ret = verify_md5(s, s->ref->frame);
-        if (ret < 0 && avctx->err_recognition & AV_EF_EXPLODE) {
+        if (ret < 0) {
             ff_hevc_unref_frame(s, s->ref, ~0);
             return ret;
         }