diff --git a/deepspeech/io/dataloader.py b/deepspeech/io/dataloader.py
index a35a0bc09695f63d5bbfa147d45b988cdf44dcab..310f5f581826460c947580a440e1aec5cc2a146a 100644
--- a/deepspeech/io/dataloader.py
+++ b/deepspeech/io/dataloader.py
@@ -44,7 +44,7 @@ def feat_dim_and_vocab_size(data_json: List[Dict[Text, Any]],
 
 
 def batch_collate(x):
-    """de-tuple.
+    """de-minibatch, since user compose batch.
 
     Args:
         x (List[Tuple]): [(utts, xs, ilens, ys, olens)]
diff --git a/examples/librispeech/s0/conf/deepspeech2.yaml b/examples/librispeech/s0/conf/deepspeech2.yaml
index 031d684d57a603a5b5b3c3ae85df6bb23c34031f..2c31e66e12207f0310d8dc1a214a02bd308f1a2f 100644
--- a/examples/librispeech/s0/conf/deepspeech2.yaml
+++ b/examples/librispeech/s0/conf/deepspeech2.yaml
@@ -4,7 +4,7 @@ data:
   dev_manifest: data/manifest.dev-clean
   test_manifest: data/manifest.test-clean
   min_input_len: 0.0
-  max_input_len: 27.0 # second
+  max_input_len: 30.0 # second
   min_output_len: 0.0
   max_output_len: .inf
   min_output_input_ratio: 0.00
diff --git a/examples/librispeech/s0/conf/deepspeech2_online.yaml b/examples/librispeech/s0/conf/deepspeech2_online.yaml
index 27f59f3fc56e593fb38cc0f029b7b5e541ae101a..87445c0b47638251a9b112c0756e76979d2579d5 100644
--- a/examples/librispeech/s0/conf/deepspeech2_online.yaml
+++ b/examples/librispeech/s0/conf/deepspeech2_online.yaml
@@ -4,7 +4,7 @@ data:
   dev_manifest: data/manifest.dev-clean
   test_manifest: data/manifest.test-clean
   min_input_len: 0.0
-  max_input_len: 27.0 # second
+  max_input_len: 30.0 # second
   min_output_len: 0.0
   max_output_len: .inf
   min_output_input_ratio: 0.00
diff --git a/examples/librispeech/s2/conf/transformer.yaml b/examples/librispeech/s2/conf/transformer.yaml
index f7c27d1f7510b2202989d9c587dda4a058e30319..4c60913e937bbd95bcd391e98a2b69a1242f63a6 100644
--- a/examples/librispeech/s2/conf/transformer.yaml
+++ b/examples/librispeech/s2/conf/transformer.yaml
@@ -22,7 +22,7 @@ collator:
   batch_frames_out: 0
   batch_frames_inout: 0
   augmentation_config: conf/augmentation.json
-  num_workers: 2
+  num_workers: 0
   subsampling_factor: 1
   num_encs: 1
 
diff --git a/examples/tiny/s0/conf/deepspeech2.yaml b/examples/tiny/s0/conf/deepspeech2.yaml
index aeb33f588961dc3e2191174fed1401f93849ff36..c93217d32f93e735ed84369fa691de86f29270bc 100644
--- a/examples/tiny/s0/conf/deepspeech2.yaml
+++ b/examples/tiny/s0/conf/deepspeech2.yaml
@@ -4,7 +4,7 @@ data:
   dev_manifest: data/manifest.tiny
   test_manifest: data/manifest.tiny 
   min_input_len: 0.0
-  max_input_len: 27.0
+  max_input_len: 30.0
   min_output_len: 0.0
   max_output_len: 400.0
   min_output_input_ratio: 0.05
diff --git a/examples/tiny/s1/conf/chunk_confermer.yaml b/examples/tiny/s1/conf/chunk_confermer.yaml
index 1b701aa26f8af36dda3be7d8b5aea8705a005ef5..96da3d9fb2f2671cc20b7454727ea1ec77ee0630 100644
--- a/examples/tiny/s1/conf/chunk_confermer.yaml
+++ b/examples/tiny/s1/conf/chunk_confermer.yaml
@@ -4,7 +4,7 @@ data:
   dev_manifest: data/manifest.tiny
   test_manifest: data/manifest.tiny
   min_input_len: 0.5  # second
-  max_input_len: 20.0 # second
+  max_input_len: 30.0 # second
   min_output_len: 0.0 # tokens
   max_output_len: 400.0 # tokens
   min_output_input_ratio: 0.05