diff --git a/parakeet/audio/__init__.py b/parakeet/audio/__init__.py
new file mode 100644
index 0000000..6212dee
--- /dev/null
+++ b/parakeet/audio/__init__.py
@@ -0,0 +1 @@
+from .audio import AudioProcessor
\ No newline at end of file
diff --git a/parakeet/audio/audio.py b/parakeet/audio/audio.py
new file mode 100644
index 0000000..b29dbf2
--- /dev/null
+++ b/parakeet/audio/audio.py
@@ -0,0 +1,261 @@
+import librosa
+import soundfile as sf
+import numpy as np
+import scipy.io
+import scipy.signal
+
+class AudioProcessor(object):
+    def __init__(self,
+                 sample_rate=None, # int, sampling rate
+                 num_mels=None, # int, bands of mel spectrogram
+                 min_level_db=None, # float, minimum level db
+                 ref_level_db=None, # float, reference level dbn
+                 n_fft=None, # int: number of samples in a frame for stft
+                 win_length=None, # int: the same meaning with n_fft
+                 hop_length=None, # int: number of samples between neighboring frame
+                 power=None, # float:power to raise before griffin-lim
+                 preemphasis=None, # float: preemphasis coefficident
+                 signal_norm=None, # 
+                 symmetric_norm=False, # bool, apply clip norm in [-max_norm, max_form]
+                 max_norm=None, # float, max norm
+                 mel_fmin=None, # int: mel spectrogram's minimum frequency
+                 mel_fmax=None, # int: mel spectrogram's maximum frequency
+                 clip_norm=True, # bool: clip spectrogram's norm
+                 griffin_lim_iters=None, # int:
+                 do_trim_silence=False, # bool: trim silience
+                 sound_norm=False,
+                 **kwargs):
+        self.sample_rate = sample_rate
+        self.num_mels = num_mels
+        self.min_level_db = min_level_db
+        self.ref_level_db = ref_level_db
+
+        # stft related
+        self.n_fft = n_fft
+        self.win_length = win_length or n_fft
+        # hop length defaults to 1/4 window_length
+        self.hop_length = hop_length or 0.25 * self.win_length 
+        
+        self.power = power
+        self.preemphasis = float(preemphasis)
+
+        self.griffin_lim_iters = griffin_lim_iters
+        self.signal_norm = signal_norm
+        self.symmetric_norm = symmetric_norm
+
+        # mel transform related
+        self.mel_fmin = mel_fmin
+        self.mel_fmax = mel_fmax
+
+        self.max_norm = 1.0 if max_norm is None else float(max_norm)
+        self.clip_norm = clip_norm
+        self.do_trim_silence = do_trim_silence
+
+        self.sound_norm = sound_norm
+        self.num_freq, self.frame_length_ms, self.frame_shift_ms = self._stft_parameters()
+
+    def _stft_parameters(self):
+        """compute frame length and hop length in ms"""
+        frame_length_ms = self.win_length * 1. / self.sample_rate
+        frame_shift_ms = self.hop_length * 1. / self.sample_rate
+        num_freq = 1 + self.n_fft // 2
+        return num_freq, frame_length_ms, frame_shift_ms
+
+    def __repr__(self):
+        """object repr"""
+        cls_name_str = self.__class__.__name__
+        members = vars(self)
+        dict_str = "\n".join(["  {}: {},".format(k, v) for k, v in members.items()])
+        repr_str = "{}(\n{})\n".format(cls_name_str, dict_str)
+        return repr_str
+
+    def save_wav(self, path, wav):
+        """save audio with scipy.io.wavfile in 16bit integers"""
+        wav_norm = wav * (32767 / max(0.01, np.max(np.abs(wav))))
+        scipy.io.wavfile.write(path, self.sample_rate, wav_norm.as_type(np.int16))
+
+    def load_wav(self, path, sr=None):
+        """load wav -> trim_silence -> rescale"""
+
+        x, sr = librosa.load(path, sr=None)
+        assert self.sample_rate == sr, "audio sample rate: {}Hz != processor sample rate: {}Hz".format(sr, self.sample_rate)
+        if self.do_trim_silence:
+            try:
+                x = self.trim_silence(x)
+            except ValueError:
+                print(" [!] File cannot be trimmed for silence - {}".format(path))
+        if self.sound_norm:
+            x = x / x.max() * 0.9 # why 0.9 ?
+        return x
+
+    def trim_silence(self, wav):
+        """Trim soilent parts with a threshold and 0.01s margin"""
+        margin = int(self.sample_rate * 0.01)
+        wav = wav[margin: -margin]
+        trimed_wav = librosa.effects.trim(wav, top_db=60, frame_length=self.win_length, hop_length=self.hop_length)[0]
+        return trimed_wav
+
+    def apply_preemphasis(self, x):
+        if self.preemphasis == 0.:
+            raise RuntimeError(" !! Preemphasis coefficient should be positive. ")
+        return scipy.signal.lfilter([1., -self.preemphasis], [1.], x)
+
+    def apply_inv_preemphasis(self, x):
+        if self.preemphasis == 0.:
+            raise RuntimeError(" !! Preemphasis coefficient should be positive. ")
+        return scipy.signal.lfilter([1.], [1., -self.preemphasis], x)
+
+    def _amplitude_to_db(self, x):
+        amplitude_min = np.exp(self.min_level_db / 20 * np.log(10))
+        return 20 * np.log10(np.maximum(amplitude_min, x))
+
+    @staticmethod
+    def _db_to_amplitude(x):
+        return np.power(10., 0.05 * x)
+
+    def _linear_to_mel(self, spectrogram):
+        _mel_basis = self._build_mel_basis()
+        return np.dot(_mel_basis, spectrogram)
+
+    def _mel_to_linear(self, mel_spectrogram):
+        inv_mel_basis = np.linalg.pinv(self._build_mel_basis())
+        return np.maximum(1e-10, np.dot(inv_mel_basis, mel_spectrogram))
+
+    def _build_mel_basis(self):
+        """return mel basis for mel scale"""
+        if self.mel_fmax is not None:
+            assert self.mel_fmax <= self.sample_rate // 2
+        return librosa.filters.mel(
+            self.sample_rate, 
+            self.n_fft, 
+            n_mels=self.num_mels,
+            fmin=self.mel_fmin,
+            fmax=self.mel_fmax)
+
+    def _normalize(self, S):
+        """put values in [0, self.max_norm] or [-self.max_norm, self,max_norm]"""
+        if self.signal_norm:
+            S_norm = (S - self.min_level_db) / (-self.min_level_db)
+            if self.symmetric_norm:
+                S_norm = ((2 * self.max_norm) * S_norm) - self.max_norm
+                if self.clip_norm:
+                    S_norm = np.clip(S_norm, -self.max_norm, self.max_norm)
+                return S_norm
+            else:
+                S_norm = self.max_norm * S_norm
+                if self.clip_norm:
+                    S_norm = np.clip(S_norm, 0, self.max_norm)
+                return S_norm
+        else:
+            return S
+
+    def _denormalize(self, S):
+        """denormalize values"""
+        S_denorm = S
+        if self.signal_norm:
+            if self.symmetric_norm:
+                if self.clip_norm:
+                    S_denorm = np.clip(S_denorm, -self.max_norm, self.max_norm)
+                S_denorm = (S_denorm + self.max_norm) * (-self.min_level_db) / (2 * self.max_norm) + self.min_level_db
+                return S_denorm
+            else:
+                if self.clip_norm:
+                    S_denorm = np.clip(S_denorm, 0, self.max_norm)
+                S_denorm = S_denorm * (-self.min_level_db)/ self.max_norm + self.min_level_db
+                return S_denorm
+        else:
+            return S
+
+    def _stft(self, y):
+        return librosa.stft(
+            y=y, 
+            n_fft=self.n_fft,
+            win_length=self.win_length,
+            hop_length=self.hop_length)
+
+    def _istft(self, S):
+        return librosa.istft(S, hop_length=self.hop_length, win_length=self.win_length)
+
+    def spectrogram(self, y):
+        """compute linear spectrogram(amplitude)
+        preemphasis -> stft -> mag -> amplitude_to_db -> minus_ref_level_db -> normalize
+        """
+        if self.preemphasis:
+            D = self._stft(self.apply_preemphasis(y))
+        else:
+            D = self._stft(y)
+        S = self._amplitude_to_db(np.abs(D)) - self.ref_level_db
+        return self._normalize(S)
+
+    def melspectrogram(self, y):
+        """compute linear spectrogram(amplitude)
+        preemphasis -> stft -> mag -> mel_scale -> amplitude_to_db -> minus_ref_level_db -> normalize
+        """
+        if self.preemphasis:
+            D = self._stft(self.apply_preemphasis(y))
+        else:
+            D = self._stft(y)
+        S = self._amplitude_to_db(self._linear_to_mel(np.abs(D))) - self.ref_level_db
+        return self._normalize(S)
+
+    def inv_spectrogram(self, spectrogram):
+        """convert spectrogram back to waveform using griffin_lim in librosa"""
+        S = self._denormalize(spectrogram)
+        S = self._db_to_amplitude(S + self.ref_level_db)
+        if self.preemphasis:
+            return self.apply_inv_preemphasis(self._griffin_lim(S ** self.power))
+        return self._griffin_lim(S ** self.power)
+
+    def inv_melspectrogram(self, mel_spectrogram):
+        S = self._denormalize(mel_spectrogram)
+        S = self._db_to_amplitude(S + self.ref_level_db)
+        S = self._linear_to_mel(np.abs(S))
+        if self.preemphasis:
+            return self.apply_inv_preemphasis(self._griffin_lim(S ** self.power))
+        return self._griffin_lim(S ** self.power)
+
+    def out_linear_to_mel(self, linear_spec):
+        """convert output linear spec to mel spec"""
+        S = self._denormalize(linear_spec)
+        S = self._db_to_amplitude(S + self.ref_level_db)
+        S = self._linear_to_mel(np.abs(S))
+        S = self._amplitude_to_db(S) - self.ref_level_db
+        mel = self._normalize(S)
+        return mel
+        
+    def _griffin_lim(self, S):
+        angles = np.exp(2j * np.pi * np.random.rand(*S.shape))
+        S_complex = np.abs(S).astype(np.complex)
+        y = self._istft(S_complex * angles)
+        for _ in range(self.griffin_lim_iters):
+            angles = np.exp(1j * np.angle(self._stft(y)))
+            y = self._istft(S_complex * angles)
+        return y
+
+    @staticmethod
+    def mulaw_encode(wav, qc):
+        mu = 2 ** qc - 1
+        # wav_abs = np.minimum(np.abs(wav), 1.0)
+        signal = np.sign(wav) * np.log(1 + mu * np.abs(wav)) / np.log(1. + mu)
+        # Quantize signal to the specified number of levels.
+        signal = (signal + 1) / 2 * mu + 0.5
+        return np.floor(signal,)
+
+    @staticmethod
+    def mulaw_decode(wav, qc):
+        """Recovers waveform from quantized values."""
+        mu = 2 ** qc - 1
+        x = np.sign(wav) / mu * ((1 + mu) ** np.abs(wav) - 1)
+        return x
+
+    @staticmethod
+    def encode_16bits(x):
+        return np.clip(x * 2**15, -2**15, 2**15 - 1).astype(np.int16)
+
+    @staticmethod
+    def quantize(x, bits):
+        return (x + 1.) * (2**bits - 1) / 2
+
+    @staticmethod
+    def dequantize(x, bits):
+        return 2 * x / (2**bits - 1) - 1
diff --git a/parakeet/data/datacargo.py b/parakeet/data/datacargo.py
index 1d7d8d5..e087a4f 100644
--- a/parakeet/data/datacargo.py
+++ b/parakeet/data/datacargo.py
@@ -2,7 +2,8 @@ from .sampler import SequentialSampler, RandomSampler, BatchSampler
 
 class DataCargo(object):
     def __init__(self, dataset, batch_size=1, sampler=None, 
-                 shuffle=False, batch_sampler=None, drop_last=False):
+                 shuffle=False, batch_sampler=None, collate_fn=None,
+                 drop_last=False):
         self.dataset = dataset
         
         if batch_sampler is not None:
@@ -21,13 +22,20 @@ class DataCargo(object):
                 sampler = RandomSampler(dataset)
             else:
                 sampler = SequentialSampler(dataset)
-            # auto_collation without custom batch_sampler
             batch_sampler = BatchSampler(sampler, batch_size, drop_last)
+        else:
+            batch_sampler = BatchSampler(sampler, batch_size, drop_last)
+
+        self.batch_sampler = batch_sampler
+
+        if collate_fn is None:
+            collate_fn = dataset._batch_examples
+        self.collate_fn = collate_fn
 
         self.batch_size = batch_size
         self.drop_last = drop_last
         self.sampler = sampler
-        self.batch_sampler = batch_sampler
+        
     
     def __iter__(self):
         return DataIterator(self)
@@ -57,6 +65,7 @@ class DataIterator(object):
         
         self._index_sampler = loader._index_sampler
         self._sampler_iter = iter(self._index_sampler)
+        self.collate_fn = loader.collate_fn
     
     def __iter__(self):
         return self
@@ -64,7 +73,7 @@ class DataIterator(object):
     def __next__(self):
         index = self._next_index()  # may raise StopIteration, TODO(chenfeiyu): use dynamic batch size
         minibatch = [self._dataset[i] for i in index] # we can abstract it, too to use dynamic batch size
-        minibatch = self._dataset._batch_examples(minibatch) # list[Example] -> Batch
+        minibatch = self.collate_fn(minibatch)
         return minibatch
     
     def _next_index(self):
diff --git a/parakeet/models/transformerTTS/config/train_postnet.yaml b/parakeet/models/transformerTTS/config/train_postnet.yaml
index 90ac94e..5753ab1 100644
--- a/parakeet/models/transformerTTS/config/train_postnet.yaml
+++ b/parakeet/models/transformerTTS/config/train_postnet.yaml
@@ -20,7 +20,7 @@ epochs: 10000
 lr: 0.001
 save_step: 500
 use_gpu: True
-use_data_parallel: False
+use_data_parallel: True
 
 data_path: ../../../dataset/LJSpeech-1.1
 save_path: ./checkpoint
diff --git a/parakeet/models/transformerTTS/config/train_transformer.yaml b/parakeet/models/transformerTTS/config/train_transformer.yaml
index 17db190..3e56a4f 100644
--- a/parakeet/models/transformerTTS/config/train_transformer.yaml
+++ b/parakeet/models/transformerTTS/config/train_transformer.yaml
@@ -21,7 +21,7 @@ lr: 0.001
 save_step: 500
 image_step: 2000
 use_gpu: True
-use_data_parallel: False
+use_data_parallel: True
 
 data_path: ../../../dataset/LJSpeech-1.1
 save_path: ./checkpoint
diff --git a/parakeet/models/transformerTTS/data.py b/parakeet/models/transformerTTS/data.py
new file mode 100644
index 0000000..f432640
--- /dev/null
+++ b/parakeet/models/transformerTTS/data.py
@@ -0,0 +1,29 @@
+from pathlib import Path
+import numpy as np
+from paddle import fluid
+from parakeet.data.sampler import DistributedSampler
+from parakeet.data.datacargo import DataCargo
+from preprocess import batch_examples, LJSpeech, batch_examples_postnet
+
+class LJSpeechLoader:
+    def __init__(self, config, nranks, rank, is_postnet=False):
+        place = fluid.CUDAPlace(rank) if config.use_gpu else fluid.CPUPlace()
+
+        LJSPEECH_ROOT = Path(config.data_path)
+        dataset = LJSpeech(LJSPEECH_ROOT)
+        sampler = DistributedSampler(len(dataset), nranks, rank)
+
+        assert config.batch_size % nranks == 0
+        each_bs = config.batch_size // nranks
+        if is_postnet:
+            dataloader = DataCargo(dataset, sampler=sampler, batch_size=each_bs, shuffle=True, collate_fn=batch_examples_postnet, drop_last=True)
+        else:
+            dataloader = DataCargo(dataset, sampler=sampler, batch_size=each_bs, shuffle=True, collate_fn=batch_examples, drop_last=True)
+        
+        self.reader = fluid.io.DataLoader.from_generator(
+            capacity=32,
+            iterable=True,
+            use_double_buffer=True,
+            return_list=True)
+        self.reader.set_batch_generator(dataloader, place)
+        
diff --git a/parakeet/models/transformerTTS/module.py b/parakeet/models/transformerTTS/module.py
index 76bdffb..f83bff5 100644
--- a/parakeet/models/transformerTTS/module.py
+++ b/parakeet/models/transformerTTS/module.py
@@ -130,7 +130,7 @@ class EncoderPrenet(dg.Layer):
         self.projection = FC(self.full_name(), num_hidden, num_hidden)
 
     def forward(self, x):
-        x = self.embedding(fluid.layers.unsqueeze(x, axes=[-1])) #(batch_size, seq_len, embending_size)
+        x = self.embedding(x) #(batch_size, seq_len, embending_size)
         x = layers.transpose(x,[0,2,1])
         x = layers.dropout(layers.relu(self.batch_norm1(self.conv1(x))), 0.2)
         x = layers.dropout(layers.relu(self.batch_norm2(self.conv2(x))), 0.2)
@@ -211,8 +211,9 @@ class ScaledDotProductAttention(dg.Layer):
         # Mask key to ignore padding
         if mask is not None:
             attention = attention * mask
-            mask = (mask == 0).astype(float) * (-2 ** 32 + 1)
+            mask = (mask == 0).astype(np.float32) * (-2 ** 32 + 1)
             attention = attention + mask
+            
 
         attention = layers.softmax(attention)
         # Mask query to ignore padding
diff --git a/parakeet/models/transformerTTS/network.py b/parakeet/models/transformerTTS/network.py
index ff25ad2..3d356dc 100644
--- a/parakeet/models/transformerTTS/network.py
+++ b/parakeet/models/transformerTTS/network.py
@@ -7,9 +7,9 @@ class Encoder(dg.Layer):
     def __init__(self, name_scope, embedding_size, num_hidden, config):
         super(Encoder, self).__init__(name_scope)
         self.num_hidden = num_hidden
-        param = fluid.ParamAttr(name='alpha')
-        self.alpha = self.create_parameter(param, shape=(1, ), dtype='float32',
-                        default_initializer = fluid.initializer.ConstantInitializer(value=1.0))
+        param = fluid.ParamAttr(name='alpha',  
+                                initializer=fluid.initializer.Constant(value=1.0))
+        self.alpha = self.create_parameter(param, shape=(1, ), dtype='float32')
         self.pos_inp = get_sinusoid_encoding_table(1024, self.num_hidden, padding_idx=0)
         self.pos_emb = dg.Embedding(name_scope=self.full_name(),
                                  size=[1024, num_hidden],
@@ -31,8 +31,8 @@ class Encoder(dg.Layer):
 
     def forward(self, x, positional):
         if fluid.framework._dygraph_tracer()._train_mode:
-            query_mask = (positional != 0).astype(float)
-            mask = (positional != 0).astype(float)
+            query_mask = (positional != 0).astype(np.float32)
+            mask = (positional != 0).astype(np.float32)
             mask = fluid.layers.expand(fluid.layers.unsqueeze(mask,[1]), [1,x.shape[1], 1])  
         else:
             query_mask, mask = None, None
@@ -42,7 +42,7 @@ class Encoder(dg.Layer):
         
         
         # Get positional encoding
-        positional = self.pos_emb(fluid.layers.unsqueeze(positional, axes=[-1])) 
+        positional = self.pos_emb(positional) 
         x = positional * self.alpha + x #(N, T, C)
        
 
@@ -102,14 +102,14 @@ class Decoder(dg.Layer):
         
         if fluid.framework._dygraph_tracer()._train_mode:
             #zeros = np.zeros(positional.shape, dtype=np.float32)
-            m_mask = (positional != 0).astype(float)
+            m_mask = (positional != 0).astype(np.float32)
             mask = np.repeat(np.expand_dims(m_mask.numpy() == 0, axis=1), decoder_len, axis=1)
             mask = mask + np.repeat(np.expand_dims(np.triu(np.ones([decoder_len, decoder_len]), 1), axis=0) ,batch_size, axis=0)
             mask = fluid.layers.cast(dg.to_variable(mask == 0), np.float32)
             
 
             # (batch_size, decoder_len, decoder_len)
-            zero_mask = fluid.layers.expand(fluid.layers.unsqueeze((c_mask != 0).astype(float), axes=2), [1,1,decoder_len])
+            zero_mask = fluid.layers.expand(fluid.layers.unsqueeze((c_mask != 0).astype(np.float32), axes=2), [1,1,decoder_len])
             # (batch_size, decoder_len, seq_len)
             zero_mask = fluid.layers.transpose(zero_mask, [0,2,1])
         
@@ -125,7 +125,7 @@ class Decoder(dg.Layer):
         query = self.linear(query)
 
         # Get position embedding
-        positional = self.pos_emb(fluid.layers.unsqueeze(positional, axes=[-1]))
+        positional = self.pos_emb(positional)
         query = positional * self.alpha + query
 
         #positional dropout
diff --git a/parakeet/models/transformerTTS/train_postnet.py b/parakeet/models/transformerTTS/train_postnet.py
index 6e32f9c..8beeece 100644
--- a/parakeet/models/transformerTTS/train_postnet.py
+++ b/parakeet/models/transformerTTS/train_postnet.py
@@ -1,13 +1,12 @@
 from network import *
-from preprocess import batch_examples_postnet, LJSpeech
 from tensorboardX import SummaryWriter
 import os
 from tqdm import tqdm
-from parakeet.data.datacargo import DataCargo
 from pathlib import Path
 import jsonargparse
 from parse import add_config_options_to_parser
 from pprint import pprint
+from data import LJSpeechLoader
 
 class MyDataParallel(dg.parallel.DataParallel):
     """
@@ -27,21 +26,15 @@ class MyDataParallel(dg.parallel.DataParallel):
                 object.__getattribute__(self, "_sub_layers")["_layers"], key)
 
 
-def main():
-    parser = jsonargparse.ArgumentParser(description="Train postnet model", formatter_class='default_argparse')
-    add_config_options_to_parser(parser)
-    cfg = parser.parse_args('-c ./config/train_postnet.yaml'.split())
+def main(cfg):
+    
+    local_rank = dg.parallel.Env().local_rank if cfg.use_data_parallel else 0
+    nranks = dg.parallel.Env().nranks if cfg.use_data_parallel else 1
     
-    local_rank = dg.parallel.Env().local_rank
-
     if local_rank == 0:
         # Print the whole config setting.
         pprint(jsonargparse.namespace_to_dict(cfg))
 
-    LJSPEECH_ROOT = Path(cfg.data_path)
-    dataset = LJSpeech(LJSPEECH_ROOT)
-    dataloader = DataCargo(dataset, batch_size=cfg.batch_size, shuffle=True, collate_fn=batch_examples_postnet, drop_last=True)
-    
     global_step = 0
     place = (fluid.CUDAPlace(dg.parallel.Env().dev_id)
              if cfg.use_data_parallel else fluid.CUDAPlace(0)
@@ -50,35 +43,10 @@ def main():
     if not os.path.exists(cfg.log_dir):
             os.mkdir(cfg.log_dir)
     path = os.path.join(cfg.log_dir,'postnet')
-    writer = SummaryWriter(path)
 
-    with dg.guard(place):
-         # dataloader
-        input_fields = {
-                'names': ['mel', 'mag'],
-                'shapes':
-                [[cfg.batch_size, None, 80], [cfg.batch_size, None, 257]], 
-                'dtypes': ['float32', 'float32'],
-                'lod_levels': [0, 0]
-            }
+    writer = SummaryWriter(path) if local_rank == 0 else None
 
-        inputs = [
-            fluid.data(
-                name=input_fields['names'][i],
-                shape=input_fields['shapes'][i],
-                dtype=input_fields['dtypes'][i],
-                lod_level=input_fields['lod_levels'][i])
-            for i in range(len(input_fields['names']))
-        ]
-
-        reader = fluid.io.DataLoader.from_generator(
-            feed_list=inputs,
-            capacity=32,
-            iterable=True,
-            use_double_buffer=True,
-            return_list=True)
-
-        
+    with dg.guard(place):   
         model = ModelPostNet('postnet', cfg)
 
         model.train()
@@ -94,9 +62,10 @@ def main():
             strategy = dg.parallel.prepare_context()
             model = MyDataParallel(model, strategy)
 
+        reader = LJSpeechLoader(cfg, nranks, local_rank, is_postnet=True).reader()
+
         for epoch in range(cfg.epochs):
-            reader.set_batch_generator(dataloader, place)
-            pbar = tqdm(reader())
+            pbar = tqdm(reader)
             for i, data in enumerate(pbar):
                 pbar.set_description('Processing at epoch %d'%epoch)
                 mel, mag = data
@@ -109,27 +78,30 @@ def main():
                 loss = layers.mean(layers.abs(layers.elementwise_sub(mag_pred, mag)))
                 if cfg.use_data_parallel:
                     loss = model.scale_loss(loss)
-
-                writer.add_scalars('training_loss',{
-                    'loss':loss.numpy(),
-                }, global_step)
-
-                loss.backward()
-                if cfg.use_data_parallel:
+                    loss.backward()
                     model.apply_collective_grads()
+                else:
+                    loss.backward()
                 optimizer.minimize(loss, grad_clip = fluid.dygraph_grad_clip.GradClipByGlobalNorm(1))
                 model.clear_gradients()
-
-                if global_step % cfg.save_step == 0:
-                    if not os.path.exists(cfg.save_path):
-                        os.mkdir(cfg.save_path)
-                    save_path = os.path.join(cfg.save_path,'postnet/%d' % global_step)
-                    dg.save_dygraph(model.state_dict(), save_path)
-                    dg.save_dygraph(optimizer.state_dict(), save_path)
-
                 
+                if local_rank==0:
+                    writer.add_scalars('training_loss',{
+                        'loss':loss.numpy(),
+                    }, global_step)
 
+                    if global_step % cfg.save_step == 0:
+                        if not os.path.exists(cfg.save_path):
+                            os.mkdir(cfg.save_path)
+                        save_path = os.path.join(cfg.save_path,'postnet/%d' % global_step)
+                        dg.save_dygraph(model.state_dict(), save_path)
+                        dg.save_dygraph(optimizer.state_dict(), save_path)
 
+        if local_rank==0:
+            writer.close()
 
 if __name__ == '__main__':
-    main()
\ No newline at end of file
+    parser = jsonargparse.ArgumentParser(description="Train postnet model", formatter_class='default_argparse')
+    add_config_options_to_parser(parser)
+    cfg = parser.parse_args('-c ./config/train_postnet.yaml'.split())
+    main(cfg)
\ No newline at end of file
diff --git a/parakeet/models/transformerTTS/train_transformer.py b/parakeet/models/transformerTTS/train_transformer.py
index 0cdbf37..065be6d 100644
--- a/parakeet/models/transformerTTS/train_transformer.py
+++ b/parakeet/models/transformerTTS/train_transformer.py
@@ -1,16 +1,15 @@
-from preprocess import batch_examples, LJSpeech
 import os
 from tqdm import tqdm
 import paddle.fluid.dygraph as dg
 import paddle.fluid.layers as layers
 from network import *
 from tensorboardX import SummaryWriter
-from parakeet.data.datacargo import DataCargo
 from pathlib import Path
 import jsonargparse
 from parse import add_config_options_to_parser
 from pprint import pprint
 from matplotlib import cm
+from data import LJSpeechLoader
 
 class MyDataParallel(dg.parallel.DataParallel):
     """
@@ -30,21 +29,14 @@ class MyDataParallel(dg.parallel.DataParallel):
                 object.__getattribute__(self, "_sub_layers")["_layers"], key)
 
 
-def main():
-    parser = jsonargparse.ArgumentParser(description="Train TransformerTTS model", formatter_class='default_argparse')
-    add_config_options_to_parser(parser)
-    cfg = parser.parse_args('-c ./config/train_transformer.yaml'.split())
-    
-    local_rank = dg.parallel.Env().local_rank
+def main(cfg):
+    local_rank = dg.parallel.Env().local_rank if cfg.use_data_parallel else 0
+    nranks = dg.parallel.Env().nranks if cfg.use_data_parallel else 1
 
     if local_rank == 0:
         # Print the whole config setting.
         pprint(jsonargparse.namespace_to_dict(cfg))
 
-
-    LJSPEECH_ROOT = Path(cfg.data_path)
-    dataset = LJSpeech(LJSPEECH_ROOT)
-    dataloader = DataCargo(dataset, batch_size=cfg.batch_size, shuffle=True, collate_fn=batch_examples, drop_last=True)
     global_step = 0
     place = (fluid.CUDAPlace(dg.parallel.Env().dev_id)
              if cfg.use_data_parallel else fluid.CUDAPlace(0)
@@ -57,39 +49,13 @@ def main():
     writer = SummaryWriter(path) if local_rank == 0 else None
     
     with dg.guard(place):
-        if cfg.use_data_parallel:
-            strategy = dg.parallel.prepare_context()
-
-        # dataloader
-        input_fields = {
-                'names': ['character', 'mel', 'mel_input', 'pos_text', 'pos_mel', 'text_len'],
-                'shapes':
-                [[cfg.batch_size, None], [cfg.batch_size, None, 80], [cfg.batch_size, None, 80], [cfg.batch_size, 1], [cfg.batch_size, 1], [cfg.batch_size, 1]],
-                'dtypes': ['float32', 'float32', 'float32', 'int64', 'int64', 'int64'],
-                'lod_levels': [0, 0, 0, 0, 0, 0]
-            }
-
-        inputs = [
-            fluid.data(
-                name=input_fields['names'][i],
-                shape=input_fields['shapes'][i],
-                dtype=input_fields['dtypes'][i],
-                lod_level=input_fields['lod_levels'][i])
-            for i in range(len(input_fields['names']))
-        ]
-
-        reader = fluid.io.DataLoader.from_generator(
-            feed_list=inputs,
-            capacity=32,
-            iterable=True,
-            use_double_buffer=True,
-            return_list=True)
-
         model = Model('transtts', cfg)
 
         model.train()
         optimizer = fluid.optimizer.AdamOptimizer(learning_rate=dg.NoamDecay(1/(4000 *( cfg.lr ** 2)), 4000))
-
+        
+        reader = LJSpeechLoader(cfg, nranks, local_rank).reader()
+        
         if cfg.checkpoint_path is not None:
             model_dict, opti_dict = fluid.dygraph.load_dygraph(cfg.checkpoint_path)
             model.set_dict(model_dict)
@@ -97,11 +63,11 @@ def main():
             print("load checkpoint!!!")
 
         if cfg.use_data_parallel:
+            strategy = dg.parallel.prepare_context()
             model = MyDataParallel(model, strategy)
-
+        
         for epoch in range(cfg.epochs):
-            reader.set_batch_generator(dataloader, place)
-            pbar = tqdm(reader())
+            pbar = tqdm(reader)
             for i, data in enumerate(pbar):
                 pbar.set_description('Processing at epoch %d'%epoch)
                 character, mel, mel_input, pos_text, pos_mel, text_length = data
@@ -114,40 +80,41 @@ def main():
                 post_mel_loss = layers.mean(layers.abs(layers.elementwise_sub(postnet_pred, mel)))
                 loss = mel_loss + post_mel_loss
 
+                if local_rank==0:
+                    writer.add_scalars('training_loss', {
+                        'mel_loss':mel_loss.numpy(),
+                        'post_mel_loss':post_mel_loss.numpy(),
+                    }, global_step)
+
+                    writer.add_scalars('alphas', {
+                        'encoder_alpha':model.encoder.alpha.numpy(),
+                        'decoder_alpha':model.decoder.alpha.numpy(),
+                    }, global_step)
+
+                    writer.add_scalar('learning_rate', optimizer._learning_rate.step().numpy(), global_step)
+
+                    if global_step % cfg.image_step == 1:
+                        for i, prob in enumerate(attn_probs):
+                            for j in range(4):
+                                    x = np.uint8(cm.viridis(prob.numpy()[j*16]) * 255)
+                                    writer.add_image('Attention_enc_%d_0'%global_step, x, i*4+j, dataformats="HWC")
+
+                        for i, prob in enumerate(attn_enc):
+                            for j in range(4):
+                                x = np.uint8(cm.viridis(prob.numpy()[j*16]) * 255)
+                                writer.add_image('Attention_enc_%d_0'%global_step, x, i*4+j, dataformats="HWC")
+
+                        for i, prob in enumerate(attn_dec):
+                            for j in range(4):
+                                x = np.uint8(cm.viridis(prob.numpy()[j*16]) * 255)
+                                writer.add_image('Attention_dec_%d_0'%global_step, x, i*4+j, dataformats="HWC")
+
                 if cfg.use_data_parallel:
                     loss = model.scale_loss(loss)
-
-                writer.add_scalars('training_loss', {
-                    'mel_loss':mel_loss.numpy(),
-                    'post_mel_loss':post_mel_loss.numpy(),
-                }, global_step)
-
-                writer.add_scalars('alphas', {
-                    'encoder_alpha':model.encoder.alpha.numpy(),
-                    'decoder_alpha':model.decoder.alpha.numpy(),
-                }, global_step)
-
-                writer.add_scalar('learning_rate', optimizer._learning_rate.step().numpy(), global_step)
-
-                if global_step % cfg.image_step == 1:
-                    for i, prob in enumerate(attn_probs):
-                       for j in range(4):
-                            x = np.uint8(cm.viridis(prob.numpy()[j*16]) * 255)
-                            writer.add_image('Attention_enc_%d_0'%global_step, x, i*4+j, dataformats="HWC")
-
-                    for i, prob in enumerate(attn_enc):
-                        for j in range(4):
-                            x = np.uint8(cm.viridis(prob.numpy()[j*16]) * 255)
-                            writer.add_image('Attention_enc_%d_0'%global_step, x, i*4+j, dataformats="HWC")
-
-                    for i, prob in enumerate(attn_dec):
-                        for j in range(4):
-                            x = np.uint8(cm.viridis(prob.numpy()[j*16]) * 255)
-                            writer.add_image('Attention_dec_%d_0'%global_step, x, i*4+j, dataformats="HWC")
-
-                loss.backward()
-                if cfg.use_data_parallel:
+                    loss.backward()
                     model.apply_collective_grads()
+                else:
+                    loss.backward()
                 optimizer.minimize(loss, grad_clip = fluid.dygraph_grad_clip.GradClipByGlobalNorm(1))
                 model.clear_gradients()
 
@@ -163,4 +130,7 @@ def main():
                     
 
 if __name__ =='__main__':
-    main()
\ No newline at end of file
+    parser = jsonargparse.ArgumentParser(description="Train TransformerTTS model", formatter_class='default_argparse')
+    add_config_options_to_parser(parser)
+    cfg = parser.parse_args('-c ./config/train_transformer.yaml'.split())
+    main(cfg)
\ No newline at end of file