diff --git a/enhancer/data/dataset.py b/enhancer/data/dataset.py
index 28f19a6..8110a2a 100644
--- a/enhancer/data/dataset.py
+++ b/enhancer/data/dataset.py
@@ -1,9 +1,11 @@
 import math
 import multiprocessing
 import os
+from itertools import chain, cycle
 from typing import Optional
 
 import pytorch_lightning as pl
+import torch
 import torch.nn.functional as F
 from torch.utils.data import DataLoader, Dataset, IterableDataset
 
@@ -55,6 +57,7 @@ class TaskDataset(pl.LightningDataModule):
         files: Files,
         valid_minutes: float = 0.20,
         duration: float = 1.0,
+        stride=None,
         sampling_rate: int = 48000,
         matching_function=None,
         batch_size=32,
@@ -65,6 +68,7 @@ class TaskDataset(pl.LightningDataModule):
         self.name = name
         self.files, self.root_dir = check_files(root_dir, files)
         self.duration = duration
+        self.stride = stride or duration
         self.sampling_rate = sampling_rate
         self.batch_size = batch_size
         self.matching_function = matching_function
@@ -90,10 +94,11 @@ class TaskDataset(pl.LightningDataModule):
                 self.name, train_clean, train_noisy, self.matching_function
             )
             train_data = fp.prepare_matching_dict()
-            self.train_data, self.val_data = self.train_valid_split(
+            train_data, self.val_data = self.train_valid_split(
                 train_data, valid_minutes=self.valid_minutes, random_state=42
             )
 
+            self.train_data = self.prepare_traindata(train_data)
             self._validation = self.prepare_mapstype(self.val_data)
 
             test_clean = os.path.join(self.root_dir, self.files.test_clean)
@@ -112,7 +117,7 @@ class TaskDataset(pl.LightningDataModule):
         valid_min_now = 0.0
         valid_indices = []
         random_indices = list(range(0, len(data)))
-        rng = create_unique_rng(random_state)
+        rng = create_unique_rng(random_state, 0)
         rng.shuffle(random_indices)
         i = 0
         while valid_min_now <= valid_minutes:
@@ -126,6 +131,33 @@ class TaskDataset(pl.LightningDataModule):
         valid_data = [item for i, item in enumerate(data) if i in valid_indices]
         return train_data, valid_data
 
+    def prepare_traindata(self, data):
+        train_data = []
+        for item in data:
+            samples_metadata = []
+            clean, noisy, total_dur = item.values()
+            num_segments = self.get_num_segments(
+                total_dur, self.duration, self.stride
+            )
+            for index in range(num_segments):
+                start = index * self.stride
+                samples_metadata.append(
+                    ({"clean": clean, "noisy": noisy}, start)
+                )
+            train_data.append(samples_metadata)
+        print(train_data[:10])
+        return train_data
+
+    @staticmethod
+    def get_num_segments(file_duration, duration, stride):
+
+        if file_duration < duration:
+            num_segments = 1
+        else:
+            num_segments = math.ceil((file_duration - duration) / stride) + 1
+
+        return num_segments
+
     def prepare_mapstype(self, data):
 
         metadata = []
@@ -142,11 +174,33 @@ class TaskDataset(pl.LightningDataModule):
                     )
         return metadata
 
+    def train_collatefn(self, batch):
+
+        output = {"noisy": [], "clean": []}
+        for item in batch:
+            output["noisy"].append(item["noisy"])
+            output["clean"].append(item["clean"])
+
+        output["clean"] = torch.stack(output["clean"], dim=0)
+        output["noisy"] = torch.stack(output["noisy"], dim=0)
+        return output
+
+    def worker_init_fn(self):
+        worker_info = torch.utils.data.get_worker_info()
+        dataset = worker_info.dataset
+        worker_id = worker_info.id
+        split_size = len(dataset.data) // worker_info.num_workers
+        dataset.data = dataset.data[
+            worker_id * split_size : (worker_id + 1) * split_size
+        ]
+
     def train_dataloader(self):
         return DataLoader(
             TrainDataset(self),
-            batch_size=self.batch_size,
+            batch_size=None,
             num_workers=self.num_workers,
+            collate_fn=self.train_collatefn,
+            worker_init_fn=self.worker_init_fn,
         )
 
     def val_dataloader(self):
@@ -227,24 +281,24 @@ class EnhancerDataset(TaskDataset):
 
         super().setup(stage=stage)
 
+    def random_sample(self, index):
+        rng = create_unique_rng(self.model.current_epoch, index)
+        return rng.sample(self.train_data, len(self.train_data))
+
     def train__iter__(self):
+        return zip(
+            *[
+                self.get_stream(self.random_sample(i))
+                for i in range(self.batch_size)
+            ]
+        )
 
-        rng = create_unique_rng(self.model.current_epoch)
+    def get_stream(self, data):
+        return chain.from_iterable(map(self.process_data, cycle(data)))
 
-        while True:
-
-            file_dict, *_ = rng.choices(
-                self.train_data,
-                k=1,
-                weights=[file["duration"] for file in self.train_data],
-            )
-            file_duration = file_dict["duration"]
-            num_segments = self.get_num_segments(
-                file_duration, self.duration, self.stride
-            )
-            for index in range(0, num_segments):
-                start_time = index * self.stride
-                yield self.prepare_segment(file_dict, start_time)
+    def process_data(self, data):
+        for item in data:
+            yield self.prepare_segment(*item)
 
     @staticmethod
     def get_num_segments(file_duration, duration, stride):
@@ -264,6 +318,7 @@ class EnhancerDataset(TaskDataset):
 
     def prepare_segment(self, file_dict: dict, start_time: float):
 
+        print(file_dict["clean"].split("/")[-1], "->", start_time)
         clean_segment = self.audio(
             file_dict["clean"], offset=start_time, duration=self.duration
         )
@@ -292,16 +347,7 @@ class EnhancerDataset(TaskDataset):
 
     def train__len__(self):
 
-        return math.ceil(
-            sum(
-                [
-                    self.get_num_segments(
-                        file["duration"], self.duration, self.stride
-                    )
-                    for file in self.train_data
-                ]
-            )
-        )
+        return sum([len(item) for item in self.train_data])
 
     def val__len__(self):
         return len(self._validation)