diff --git a/tensor2tensor/bin/t2t-datagen b/tensor2tensor/bin/t2t-datagen
old mode 100644
new mode 100755
index 2ac0f0db2..67890371b
--- a/tensor2tensor/bin/t2t-datagen
+++ b/tensor2tensor/bin/t2t-datagen
@@ -112,7 +112,7 @@ _SUPPORTED_PROBLEM_GENERATORS = {
             vocab_filename="vocab.endefr.%d" % 2**15, vocab_size=2**15),
         lambda: audio.timit_generator(
             FLAGS.data_dir, FLAGS.tmp_dir, False, 626,
-            vocab_filename="vocab.endefr.%d" % 2**15, vocab_size=2**15)),
+            vocab_filename="vocab.endefr.%d" % 2**15, vocab_size=2**15)),     
 }
 
 # pylint: enable=g-long-lambda
diff --git a/tensor2tensor/data_generators/all_problems.py b/tensor2tensor/data_generators/all_problems.py
index c7f364cf1..2aca3d377 100644
--- a/tensor2tensor/data_generators/all_problems.py
+++ b/tensor2tensor/data_generators/all_problems.py
@@ -28,6 +28,7 @@
 from tensor2tensor.data_generators import ice_parsing
 from tensor2tensor.data_generators import image
 from tensor2tensor.data_generators import imdb
+from tensor2tensor.data_generators import librispeech
 from tensor2tensor.data_generators import lm1b
 from tensor2tensor.data_generators import multinli
 from tensor2tensor.data_generators import problem_hparams
diff --git a/tensor2tensor/data_generators/librispeech.py b/tensor2tensor/data_generators/librispeech.py
new file mode 100644
index 000000000..de7ed94cc
--- /dev/null
+++ b/tensor2tensor/data_generators/librispeech.py
@@ -0,0 +1,310 @@
+from tensor2tensor.data_generators import problem
+from tensor2tensor.utils import registry
+from tensor2tensor.models import transformer
+from tensor2tensor.utils import modality
+from tensor2tensor.layers import common_layers
+from tensor2tensor.data_generators import text_encoder
+import random
+import tensorflow as tf
+import numpy as np
+from tensor2tensor.data_generators import generator_utils
+import os
+from subprocess import call
+import tarfile
+import wave
+      
+
+_LIBRISPEECH_TRAIN_DATASETS = [
+    [
+        "http://www.openslr.org/resources/12/train-clean-100.tar.gz",  # pylint: disable=line-too-long
+        "train-clean-100"
+    ],
+    [
+        "http://www.openslr.org/resources/12/train-clean-360.tar.gz",
+        "train-clean-360"
+    ],
+    [
+        "http://www.openslr.org/resources/12/train-other-500.tar.gz",
+        "train-other-500"
+    ],
+]
+_LIBRISPEECH_TEST_DATASETS = [
+    [
+        "http://www.openslr.org/resources/12/dev-clean.tar.gz",
+        "dev-clean"
+    ],
+    [
+        "http://www.openslr.org/resources/12/dev-other.tar.gz",
+        "dev-other"
+    ],
+]
+
+
+def _collect_data(directory, input_ext, transcription_ext):
+  """Traverses directory collecting input and target files."""
+  # Directory from string to tuple pair of strings
+  # key: the filepath to a datafile including the datafile's basename. Example,
+  #   if the datafile was "/path/to/datafile.wav" then the key would be
+  #   "/path/to/datafile"
+  # value: a pair of strings (media_filepath, label)
+  data_files = dict()
+  for root, _, filenames in os.walk(directory):
+    transcripts = [filename for filename in filenames if transcription_ext in filename]
+    for transcript in transcripts:
+      basename = transcript.strip(transcription_ext)
+      transcript_path = os.path.join(root, transcript)
+      with open(transcript_path, 'r') as transcript_file:
+        for transcript_line in transcript_file:
+          line_contents = transcript_line.split(" ", 1)
+          assert len(line_contents) == 2
+          media_base, label = line_contents
+          key = os.path.join(root, media_base)
+          assert key not in data_files
+          media_name = "%s.%s"%(media_base, input_ext)
+          media_path = os.path.join(root, media_name)
+          data_files[key] = (media_path, label)
+  return data_files
+
+
+def _get_audio_data(filepath):
+  # Construct a true .wav file.
+  out_filepath = filepath.strip(".flac") + ".wav"
+  # Assumes sox is installed on system. Sox converts from FLAC to WAV.
+  call(["sox", filepath, out_filepath])
+  wav_file = wave.open(open(out_filepath))
+  frame_count = wav_file.getnframes()
+  byte_array = wav_file.readframes(frame_count)
+  
+  data = np.fromstring(byte_array, np.uint8).tolist()
+  return data, frame_count, wav_file.getsampwidth(), wav_file.getnchannels()
+      
+
+class LibrispeechTextEncoder(text_encoder.TextEncoder):
+
+  def encode(self, s):
+    return [self._num_reserved_ids + ord(c) for c in s]
+
+  def decode(self, ids):
+    """Transform a sequence of int ids into a human-readable string.
+    EOS is not expected in ids.
+    Args:
+      ids: list of integers to be converted.
+    Returns:
+      s: human-readable string.
+    """
+    decoded_ids = []
+    for id_ in ids:
+      if 0 <= id_ < self._num_reserved_ids:
+        decoded_ids.append(RESERVED_TOKENS[int(id_)])
+      else:
+        decoded_ids.append(id_ - self._num_reserved_ids)
+    return "".join([chr(d) for d in decoded_ids])
+ 
+
+      
+@registry.register_audio_modality
+class LibrispeechModality(modality.Modality):
+  """Performs strided conv compressions for audio spectral data."""
+
+  def bottom(self, inputs):
+    """Transform input from data space to model space.
+    Args:
+      inputs: A Tensor with shape [batch, ...]
+    Returns:
+      body_input: A Tensor with shape [batch, ?, ?, body_input_depth].
+    """
+    with tf.variable_scope(self.name):
+      # TODO(aidangomez): Will need to sort out a better audio pipeline
+      def xnet_resblock(x, filters, res_relu, name):
+        with tf.variable_scope(name):
+          # We only stride along the length dimension to preserve the spectral
+          # bins (which are tiny in dimensionality relative to length)
+          y = common_layers.separable_conv_block(
+              x,
+              filters, [((1, 1), (3, 3)), ((1, 1), (3, 3))],
+              first_relu=True,
+              padding="SAME",
+              force2d=True,
+              name="sep_conv_block")
+          y = common_layers.pool(y, (3, 3), "MAX", "SAME", strides=(2, 1))
+          return y + common_layers.conv_block(
+              x,
+              filters, [((1, 1), (1, 1))],
+              padding="SAME",
+              strides=(2, 1),
+              first_relu=res_relu,
+              force2d=True,
+              name="res_conv0")
+
+      # Rescale from UINT8 to floats in [-1,-1]
+      signals = (tf.to_float(inputs)-127)/128.
+      #signals = tf.contrib.framework.nest.flatten(signals)
+      signals = tf.squeeze(signals, [2, 3])
+      
+      # `stfts` is a complex64 Tensor representing the Short-time Fourier Transform of
+      # each signal in `signals`. Its shape is [batch_size, ?, fft_unique_bins]
+      # where fft_unique_bins = fft_length // 2 + 1 = 513.
+      stfts = tf.contrib.signal.stft(signals, frame_length=1024, frame_step=512,
+                               fft_length=1024)
+                               
+      # An energy spectrogram is the magnitude of the complex-valued STFT.
+      # A float32 Tensor of shape [batch_size, ?, 513].
+      magnitude_spectrograms = tf.abs(stfts)
+      
+      log_offset = 1e-6
+      log_magnitude_spectrograms = tf.log(magnitude_spectrograms + log_offset)
+      
+      # Warp the linear-scale, magnitude spectrograms into the mel-scale.
+      num_spectrogram_bins = magnitude_spectrograms.shape[-1].value
+      lower_edge_hertz, upper_edge_hertz, num_mel_bins = 80.0, 7600.0, 64
+      sample_rate = 16000
+      linear_to_mel_weight_matrix = tf.contrib.signal.linear_to_mel_weight_matrix(
+        num_mel_bins, num_spectrogram_bins, sample_rate, lower_edge_hertz,
+        upper_edge_hertz)
+      mel_spectrograms = tf.tensordot(
+        magnitude_spectrograms, linear_to_mel_weight_matrix, 1)
+      # Note: Shape inference for `tf.tensordot` does not currently handle this case.
+      mel_spectrograms.set_shape(magnitude_spectrograms.shape[:-1].concatenate(
+        linear_to_mel_weight_matrix.shape[-1:]))
+      
+      # Try without the conversion to MFCCs, first.
+      '''num_mfccs = 13
+      # Keep the first `num_mfccs` MFCCs.
+      mfccs = tf.contrib.signal.mfccs_from_log_mel_spectrograms(
+        log_mel_spectrograms)[..., :num_mfccs]'''  
+              
+      x = tf.expand_dims(mel_spectrograms, 2)
+      x.set_shape([None, None, None, num_mel_bins])
+      for i in xrange(self._model_hparams.audio_compression):
+        x = xnet_resblock(x, 2**(i + 1), True, "compress_block_%d" % i)
+      return xnet_resblock(x, self._body_input_depth, False,
+                           "compress_block_final")
+                           
+                           
+@registry.register_problem()
+class Librispeech(problem.Problem):
+  """Problem spec for English word to dictionary definition."""
+
+  @property
+  def is_character_level(self):
+    return True
+
+  @property
+  def input_space_id(self):
+    return problem.SpaceID.AUDIO_SPECTRAL
+
+  @property
+  def target_space_id(self):
+    return problem.SpaceID.EN_CHR
+
+  @property
+  def num_shards(self):
+    return 100
+
+  @property
+  def use_subword_tokenizer(self):
+    return False
+    
+  @property
+  def num_dev_shards(self):
+    return 1
+    
+  @property
+  def use_train_shards_for_dev(self):
+    """If true, we only generate training data and hold out shards for dev."""
+    return False
+          
+  def feature_encoders(self, _):
+    return {
+        "inputs": text_encoder.TextEncoder(),
+        "targets": LibrispeechTextEncoder(),
+    }
+    
+  def example_reading_spec(self):
+    data_fields = {
+        "inputs": tf.VarLenFeature(tf.int64),
+        #"audio/channel_count": tf.FixedLenFeature([], tf.int64),
+        #"audio/sample_count": tf.FixedLenFeature([], tf.int64),
+        #"audio/sample_width": tf.FixedLenFeature([], tf.int64),
+        "targets": tf.VarLenFeature(tf.int64),
+    }
+    data_items_to_decoders = None
+    return (data_fields, data_items_to_decoders)
+
+    
+  def generator(self, data_dir, tmp_dir, training, eos_list=None, start_from=0, how_many=0):
+    eos_list = [1] if eos_list is None else eos_list
+    datasets = (_LIBRISPEECH_TRAIN_DATASETS if training else _LIBRISPEECH_TEST_DATASETS)
+    num_reserved_ids = self.feature_encoders(None)["targets"].num_reserved_ids
+    i = 0
+    for url, subdir in datasets:
+      filename = os.path.basename(url)
+      compressed_file = generator_utils.maybe_download(tmp_dir, filename, url)
+
+      read_type = "r:gz" if filename.endswith("tgz") else "r"
+      with tarfile.open(compressed_file, read_type) as corpus_tar:
+        # Create a subset of files that don't already exist.
+        #   tarfile.extractall errors when encountering an existing file
+        #   and tarfile.extract is extremely slow
+        members = []
+        for f in corpus_tar:
+          if not os.path.isfile(os.path.join(tmp_dir, f.name)):
+            members.append(f)
+        corpus_tar.extractall(tmp_dir, members=members)
+  
+      data_dir = os.path.join(tmp_dir, "LibriSpeech", subdir)
+      data_files = _collect_data(data_dir, "flac", "txt")
+      data_pairs = data_files.values()
+      for media_file, text_data in sorted(data_pairs)[start_from:]:
+        if how_many > 0 and i == how_many:
+          return
+        i += 1
+        audio_data, sample_count, sample_width, num_channels = _get_audio_data(
+            media_file)
+        label = [num_reserved_ids + ord(c) for c in text_data] + eos_list
+        yield {
+            "inputs": audio_data,
+            "audio/channel_count": [num_channels],
+            "audio/sample_count": [sample_count],
+            "audio/sample_width": [sample_width],
+            "targets": label
+        }
+        
+        
+  def generate_data(self, data_dir, tmp_dir, task_id=-1):
+    train_paths = self.training_filepaths(data_dir, self.num_shards, shuffled=False)
+    dev_paths = self.dev_filepaths(data_dir, self.num_dev_shards, shuffled=False)
+    if self.use_train_shards_for_dev:
+      all_paths = train_paths + dev_paths
+      generator_utils.generate_files(self.generator(data_dir, tmp_dir, True), all_paths)
+      generator_utils.shuffle_dataset(all_paths)
+    else:
+      generator_utils.generate_dataset_and_shuffle(
+          self.generator(data_dir, tmp_dir, True), train_paths,
+          self.generator(data_dir, tmp_dir, False), dev_paths)
+      
+    
+  def hparams(self, defaults, unused_model_hparams):
+    p = defaults    
+    p.stop_at_eos = int(False)
+    p.input_modality = { "inputs": ("audio:librispeech_modality", None) }      
+    p.target_modality = (registry.Modalities.SYMBOL, 256)
+    
+  def preprocess_example(self, example, mode, hparams):    
+    return example
+    
+# TODO: clean up hparams
+@registry.register_hparams
+def librispeech_hparams():
+    hparams = transformer.transformer_base_single_gpu()  # Or whatever you'd like to build off.
+    hparams.batch_size = 36
+    hparams.audio_compression = 8
+    hparams.hidden_size = 2048    
+    hparams.max_input_seq_length = 600000
+    hparams.max_target_seq_length = 350    
+    hparams.max_length = hparams.max_input_seq_length
+    hparams.min_length_bucket = hparams.max_input_seq_length // 2 
+    hparams.learning_rate = 0.05
+    hparams.train_steps = 5000000    
+    hparams.num_hidden_layers = 4
+    return hparams