diff --git a/examples/librispeech/s1/conf/chunk_conformer.yaml b/examples/librispeech/s1/conf/chunk_conformer.yaml
index 7a4ddf5d..0de1aefe 100644
--- a/examples/librispeech/s1/conf/chunk_conformer.yaml
+++ b/examples/librispeech/s1/conf/chunk_conformer.yaml
@@ -110,7 +110,7 @@ decoding:
   cutoff_top_n: 0
   num_proc_bsearch: 8
   ctc_weight: 0.5 # ctc weight for attention rescoring decode mode.
-  decoding_chunk_size: 16 # decoding chunk size. Defaults to -1.
+  decoding_chunk_size: -1 # decoding chunk size. Defaults to -1.
       # <0: for decoding, use full chunk.
       # >0: for decoding, use fixed chunk size as set.
       # 0: used for training, it's prohibited here.