diff --git a/nobrainer/dataset.py b/nobrainer/dataset.py
index 9a54f686..ff5eef18 100644
--- a/nobrainer/dataset.py
+++ b/nobrainer/dataset.py
@@ -75,6 +75,7 @@ def from_tfrecords(
         file_pattern=None,
         n_volumes=None,
         volume_shape=None,
+        block_shape=None,
         scalar_labels=False,
         n_classes=1,
         num_parallel_calls=1,
@@ -123,7 +124,16 @@ def from_tfrecords(
             num_parallel_calls=num_parallel_calls,
         )
         dataset = dataset.map(map_func=parse_fn, num_parallel_calls=num_parallel_calls)
-        return cls(dataset, n_volumes, volume_shape, n_classes)
+        ds_obj = cls(dataset, n_volumes, volume_shape, n_classes)
+
+        if block_shape:
+            ds_obj.block(block_shape)
+        ds_obj.map_labels()
+
+        # TODO automatically determine batch size
+        ds_obj.batch(1)
+
+        return ds_obj
 
     @classmethod
     def from_files(
@@ -137,6 +147,7 @@ def from_files(
         num_parallel_calls=1,
         eval_size=0.1,
         n_classes=1,
+        block_shape=None,
     ):
         """Create Nobrainer datasets from data
         filepaths: List(str), list of paths to individual input data files.
@@ -195,6 +206,7 @@ def from_files(
             volume_shape,
             scalar_labels=scalar_labels,
             n_classes=n_classes,
+            block_shape=block_shape,
             num_parallel_calls=num_parallel_calls,
         )
         ds_eval = None
@@ -206,6 +218,7 @@ def from_files(
                 volume_shape,
                 scalar_labels=scalar_labels,
                 n_classes=n_classes,
+                block_shape=block_shape,
                 num_parallel_calls=num_parallel_calls,
             )
         return ds_train, ds_eval
@@ -277,17 +290,19 @@ def _f(x, y):
         self.dataset = self.dataset.unbatch()
         return self
 
-    def map_labels(self, n_classes, label_mapping=None):
-        if n_classes < 1:
+    def map_labels(self, label_mapping=None):
+        if self.n_classes < 1:
             raise ValueError("n_classes must be > 0.")
-        if n_classes == 1:
+
+        if label_mapping is not None:
+            self.map(
+                lambda x, y: (x, replace(y, label_mapping=label_mapping)))
+
+        if self.n_classes == 1:
             self.map(lambda x, y: (x, tf.expand_dims(binarize(y), -1)))
-        elif n_classes == 2:
+        elif self.n_classes == 2:
             self.map(lambda x, y: (x, tf.one_hot(binarize(y), n_classes)))
-        elif n_classes > 2:
-            if label_mapping is not None:
-                self.map(
-                    lambda x, y: (x, replace(y, label_mapping=label_mapping)))
+        elif self.n_classes > 2:
             self.map(lambda x, y: (x, tf.one_hot(y, n_classes)))
 
         return self