def eval_model(attention, mel_prediction, target_spectrogram, input_seq, step,
               plot_dir, mel_output_dir, wav_dir, sample_num, loss, hparams):
    # Save some results for evaluation
    attention_path = str(plot_dir.joinpath("attention_step_{}_sample_{}".format(step, sample_num)))
    save_attention(attention, attention_path)

    # save predicted mel spectrogram to disk (debug)
    mel_output_fpath = mel_output_dir.joinpath("mel-prediction-step-{}_sample_{}.npy".format(step, sample_num))
    np.save(str(mel_output_fpath), mel_prediction, allow_pickle=False)

    # save griffin lim inverted wav for debug (mel -> wav)
    # wav = audio.inv_mel_spectrogram(mel_prediction.T, hparams)
    # wav_fpath = wav_dir.joinpath("step-{}-wave-from-mel_sample_{}.wav".format(step, sample_num))
    # audio.save_wav(wav, str(wav_fpath), sr=hparams.sample_rate)


    os.makedirs('log_wavs', exist_ok=True)
    _wav_pre = mel2wav(mel_prediction, wav_name_path=os.path.join('log_wavs', str(step) + '_pre.wav'))
    _wav_target = mel2wav(target_spectrogram, wav_name_path=os.path.join('log_wavs', str(step) + '_target.wav'))




    # save real and predicted mel-spectrogram plot to disk (control purposes)
    spec_fpath = plot_dir.joinpath("step-{}-mel-spectrogram_sample_{}.png".format(step, sample_num))
    title_str = "{}, {}, step={}, loss={:.5f}".format("Tacotron", time_string(), step, loss)
    plot_spectrogram(mel_prediction, str(spec_fpath), title=title_str,
                     target_spectrogram=target_spectrogram,
                     max_len=target_spectrogram.size // hparams.num_mels)
    print("Input at step {}: {}".format(step, sequence_to_text(input_seq)))
Пример #2
0
def train(log_dir, args, hparams):
    save_dir = os.path.join(log_dir, "taco_pretrained")
    plot_dir = os.path.join(log_dir, "plots")
    wav_dir = os.path.join(log_dir, "wavs")
    mel_dir = os.path.join(log_dir, "mel-spectrograms")
    eval_dir = os.path.join(log_dir, "eval-dir")
    eval_plot_dir = os.path.join(eval_dir, "plots")
    eval_wav_dir = os.path.join(eval_dir, "wavs")
    tensorboard_dir = os.path.join(log_dir, "tacotron_events")
    meta_folder = os.path.join(log_dir, "metas")
    os.makedirs(save_dir, exist_ok=True)
    os.makedirs(plot_dir, exist_ok=True)
    os.makedirs(wav_dir, exist_ok=True)
    os.makedirs(mel_dir, exist_ok=True)
    os.makedirs(eval_dir, exist_ok=True)
    os.makedirs(eval_plot_dir, exist_ok=True)
    os.makedirs(eval_wav_dir, exist_ok=True)
    os.makedirs(tensorboard_dir, exist_ok=True)
    os.makedirs(meta_folder, exist_ok=True)

    checkpoint_fpath = os.path.join(save_dir, "tacotron_model.ckpt")
    if hparams.if_use_speaker_classifier:
        metadat_fpath = os.path.join(args.synthesizer_root,
                                     "train_augment_speaker.txt")
    else:
        metadat_fpath = os.path.join(args.synthesizer_root, "train.txt")

    log("Checkpoint path: {}".format(checkpoint_fpath))
    log("Loading training data from: {}".format(metadat_fpath))
    log("Using model: Tacotron")
    log(hparams_debug_string())

    # Start by setting a seed for repeatability
    tf.set_random_seed(hparams.tacotron_random_seed)

    # Set up data feeder
    coord = tf.train.Coordinator()
    with tf.variable_scope("datafeeder") as scope:
        feeder = Feeder(coord, metadat_fpath, hparams)

    # Set up model:
    global_step = tf.Variable(0, name="global_step", trainable=False)
    model, stats = model_train_mode(args, feeder, hparams, global_step)
    eval_model = model_test_mode(args, feeder, hparams, global_step)

    # Embeddings metadata
    char_embedding_meta = os.path.join(meta_folder, "CharacterEmbeddings.tsv")
    if not os.path.isfile(char_embedding_meta):
        with open(char_embedding_meta, "w", encoding="utf-8") as f:
            for symbol in symbols:
                if symbol == " ":
                    symbol = "\\s"  # For visual purposes, swap space with \s

                f.write("{}\n".format(symbol))

    char_embedding_meta = char_embedding_meta.replace(log_dir, "..")

    # Book keeping
    step = 0
    time_window = ValueWindow(100)
    loss_window = ValueWindow(100)
    saver = tf.train.Saver(max_to_keep=5)

    log("Tacotron training set to a maximum of {} steps".format(
        args.tacotron_train_steps))

    # Memory allocation on the GPU as needed
    config = tf.ConfigProto()
    config.gpu_options.allow_growth = True
    config.allow_soft_placement = True

    # Train
    with tf.Session(config=config) as sess:
        try:
            summary_writer = tf.summary.FileWriter(tensorboard_dir, sess.graph)

            sess.run(tf.global_variables_initializer())

            # saved model restoring
            if args.restore:
                # Restore saved model if the user requested it, default = True
                try:
                    checkpoint_state = tf.train.get_checkpoint_state(save_dir)

                    if checkpoint_state and checkpoint_state.model_checkpoint_path:
                        log("Loading checkpoint {}".format(
                            checkpoint_state.model_checkpoint_path),
                            slack=True)
                        saver.restore(sess,
                                      checkpoint_state.model_checkpoint_path)

                    else:
                        log("No model to load at {}".format(save_dir),
                            slack=True)
                        saver.save(sess,
                                   checkpoint_fpath,
                                   global_step=global_step)

                except tf.errors.OutOfRangeError as e:
                    log("Cannot restore checkpoint: {}".format(e), slack=True)
            else:
                log("Starting new training!", slack=True)
                saver.save(sess, checkpoint_fpath, global_step=global_step)

            # initializing feeder
            feeder.start_threads(sess)

            # Training loop
            while not coord.should_stop() and step < args.tacotron_train_steps:
                start_time = time.time()
                step, loss, adversial_loss, opt = sess.run([
                    global_step, model.loss, model.adversial_loss,
                    model.optimize
                ])
                loss -= adversial_loss
                time_window.append(time.time() - start_time)
                loss_window.append(loss)
                message = "Step {:7d} [{:.3f} sec/step, loss={:.5f}, avg_loss={:.5f}, adv_loss={:.5f}]".format(
                    step, time_window.average, loss, loss_window.average,
                    adversial_loss)
                log(message,
                    end="\r",
                    slack=(step % args.checkpoint_interval == 0))
                print(message)

                if loss > 100 or np.isnan(loss):
                    log("Loss exploded to {:.5f} at step {}".format(
                        loss, step))
                    raise Exception("Loss exploded")

                if step % args.summary_interval == 0:
                    log("\nWriting summary at step {}".format(step))
                    summary_writer.add_summary(sess.run(stats), step)

                if step % args.eval_interval == 0:
                    # Run eval and save eval stats
                    log("\nRunning evaluation at step {}".format(step))

                    eval_losses = []
                    before_losses = []
                    after_losses = []
                    stop_token_losses = []
                    linear_losses = []
                    linear_loss = None
                    adversial_losses = []

                    if hparams.predict_linear:
                        for i in tqdm(range(feeder.test_steps)):
                            eloss, before_loss, after_loss, stop_token_loss, linear_loss, mel_p, \
       mel_t, t_len, align, lin_p, lin_t = sess.run(
                                [
                                    eval_model.tower_loss[0], eval_model.tower_before_loss[0],
                                    eval_model.tower_after_loss[0],
                                    eval_model.tower_stop_token_loss[0],
                                    eval_model.tower_linear_loss[0],
                                    eval_model.tower_mel_outputs[0][0],
                                    eval_model.tower_mel_targets[0][0],
                                    eval_model.tower_targets_lengths[0][0],
                                    eval_model.tower_alignments[0][0],
                                    eval_model.tower_linear_outputs[0][0],
                                    eval_model.tower_linear_targets[0][0],
                                ])
                            eval_losses.append(eloss)
                            before_losses.append(before_loss)
                            after_losses.append(after_loss)
                            stop_token_losses.append(stop_token_loss)
                            linear_losses.append(linear_loss)
                        linear_loss = sum(linear_losses) / len(linear_losses)

                        wav = audio.inv_linear_spectrogram(lin_p.T, hparams)
                        audio.save_wav(
                            wav,
                            os.path.join(
                                eval_wav_dir,
                                "step-{}-eval-wave-from-linear.wav".format(
                                    step)),
                            sr=hparams.sample_rate)

                    else:
                        for i in tqdm(range(feeder.test_steps)):
                            eloss, before_loss, after_loss, stop_token_loss, adversial_loss, mel_p, mel_t, t_len,\
       align = sess.run(
                                [
                                    eval_model.tower_loss[0], eval_model.tower_before_loss[0],
                                    eval_model.tower_after_loss[0],
                                    eval_model.tower_stop_token_loss[0],
                                    eval_model.tower_adversial_loss[0],
                                    eval_model.tower_mel_outputs[0][0],
                                    eval_model.tower_mel_targets[0][0],
                                    eval_model.tower_targets_lengths[0][0],
                                    eval_model.tower_alignments[0][0]
                                ])
                            eval_losses.append(eloss)
                            before_losses.append(before_loss)
                            after_losses.append(after_loss)
                            stop_token_losses.append(stop_token_loss)
                            adversial_losses.append(adversial_loss)

                    eval_loss = sum(eval_losses) / len(eval_losses)
                    before_loss = sum(before_losses) / len(before_losses)
                    after_loss = sum(after_losses) / len(after_losses)
                    stop_token_loss = sum(stop_token_losses) / len(
                        stop_token_losses)
                    adversial_loss = sum(adversial_losses) / len(
                        adversial_losses)

                    log("Saving eval log to {}..".format(eval_dir))
                    # Save some log to monitor model improvement on same unseen sequence
                    wav = audio.inv_mel_spectrogram(mel_p.T, hparams)
                    audio.save_wav(
                        wav,
                        os.path.join(
                            eval_wav_dir,
                            "step-{}-eval-wave-from-mel.wav".format(step)),
                        sr=hparams.sample_rate)

                    plot.plot_alignment(
                        align,
                        os.path.join(eval_plot_dir,
                                     "step-{}-eval-align.png".format(step)),
                        title="{}, {}, step={}, loss={:.5f}".format(
                            "Tacotron", time_string(), step, eval_loss),
                        max_len=t_len // hparams.outputs_per_step)
                    plot.plot_spectrogram(
                        mel_p,
                        os.path.join(
                            eval_plot_dir, "step-{"
                            "}-eval-mel-spectrogram.png".format(step)),
                        title="{}, {}, step={}, loss={:.5f}".format(
                            "Tacotron", time_string(), step, eval_loss),
                        target_spectrogram=mel_t,
                        max_len=t_len)

                    if hparams.predict_linear:
                        plot.plot_spectrogram(
                            lin_p,
                            os.path.join(
                                eval_plot_dir,
                                "step-{}-eval-linear-spectrogram.png".format(
                                    step)),
                            title="{}, {}, step={}, loss={:.5f}".format(
                                "Tacotron", time_string(), step, eval_loss),
                            target_spectrogram=lin_t,
                            max_len=t_len,
                            auto_aspect=True)

                    log("Eval loss for global step {}: {:.3f}".format(
                        step, eval_loss))
                    log("Writing eval summary!")
                    add_eval_stats(summary_writer, step, linear_loss,
                                   before_loss, after_loss, stop_token_loss,
                                   adversial_loss, eval_loss)

                if step % args.checkpoint_interval == 0 or step == args.tacotron_train_steps or \
                        step == 300:
                    # Save model and current global step
                    saver.save(sess, checkpoint_fpath, global_step=global_step)

                    log("\nSaving alignment, Mel-Spectrograms and griffin-lim inverted waveform.."
                        )
                    input_seq, mel_prediction, alignment, target, target_length = sess.run(
                        [
                            model.tower_inputs[0][0],
                            model.tower_mel_outputs[0][0],
                            model.tower_alignments[0][0],
                            model.tower_mel_targets[0][0],
                            model.tower_targets_lengths[0][0],
                        ])

                    # save predicted mel spectrogram to disk (debug)
                    mel_filename = "mel-prediction-step-{}.npy".format(step)
                    np.save(os.path.join(mel_dir, mel_filename),
                            mel_prediction.T,
                            allow_pickle=False)

                    # save griffin lim inverted wav for debug (mel -> wav)
                    wav = audio.inv_mel_spectrogram(mel_prediction.T, hparams)
                    audio.save_wav(
                        wav,
                        os.path.join(wav_dir,
                                     "step-{}-wave-from-mel.wav".format(step)),
                        sr=hparams.sample_rate)

                    # save alignment plot to disk (control purposes)
                    plot.plot_alignment(
                        alignment,
                        os.path.join(plot_dir,
                                     "step-{}-align.png".format(step)),
                        title="{}, {}, step={}, loss={:.5f}".format(
                            "Tacotron", time_string(), step, loss),
                        max_len=target_length // hparams.outputs_per_step)
                    # save real and predicted mel-spectrogram plot to disk (control purposes)
                    plot.plot_spectrogram(
                        mel_prediction,
                        os.path.join(
                            plot_dir,
                            "step-{}-mel-spectrogram.png".format(step)),
                        title="{}, {}, step={}, loss={:.5f}".format(
                            "Tacotron", time_string(), step, loss),
                        target_spectrogram=target,
                        max_len=target_length)
                    #log("Input at step {}: {}".format(step, sequence_to_text(input_seq)))

                if step % args.embedding_interval == 0 or step == args.tacotron_train_steps or step == 1:
                    # Get current checkpoint state
                    checkpoint_state = tf.train.get_checkpoint_state(save_dir)

                    # Update Projector
                    #log("\nSaving Model Character Embeddings visualization..")
                    #add_embedding_stats(summary_writer, [model.embedding_table.name],
                    #                    [char_embedding_meta],
                    #                    checkpoint_state.model_checkpoint_path)
                    #log("Tacotron Character embeddings have been updated on tensorboard!")

            log("Tacotron training complete after {} global steps!".format(
                args.tacotron_train_steps),
                slack=True)
            return save_dir

        except Exception as e:
            log("Exiting due to exception: {}".format(e), slack=True)
            traceback.print_exc()
            coord.request_stop(e)
Пример #3
0
    def synthesize(self, texts, basenames, out_dir, log_dir, mel_filenames,
                   embed_filenames):
        hparams = self._hparams
        cleaner_names = [x.strip() for x in hparams.cleaners.split(",")]

        assert 0 == len(texts) % self._hparams.tacotron_num_gpus
        seqs = [
            np.asarray(text_to_sequence(text, cleaner_names)) for text in texts
        ]
        input_lengths = [len(seq) for seq in seqs]

        size_per_device = len(seqs) // self._hparams.tacotron_num_gpus

        #Pad inputs according to each GPU max length
        input_seqs = None
        split_infos = []
        for i in range(self._hparams.tacotron_num_gpus):
            device_input = seqs[size_per_device * i:size_per_device * (i + 1)]
            device_input, max_seq_len = self._prepare_inputs(device_input)
            input_seqs = np.concatenate(
                (input_seqs, device_input),
                axis=1) if input_seqs is not None else device_input
            split_infos.append([max_seq_len, 0, 0, 0])

        feed_dict = {
            self.inputs: input_seqs,
            self.input_lengths: np.asarray(input_lengths, dtype=np.int32),
        }

        if self.gta:
            np_targets = [
                np.load(mel_filename) for mel_filename in mel_filenames
            ]
            target_lengths = [len(np_target) for np_target in np_targets]

            #pad targets according to each GPU max length
            target_seqs = None
            for i in range(self._hparams.tacotron_num_gpus):
                device_target = np_targets[size_per_device *
                                           i:size_per_device * (i + 1)]
                device_target, max_target_len = self._prepare_targets(
                    device_target, self._hparams.outputs_per_step)
                target_seqs = np.concatenate(
                    (target_seqs, device_target),
                    axis=1) if target_seqs is not None else device_target
                split_infos[i][
                    1] = max_target_len  #Not really used but setting it in case for future development maybe?

            feed_dict[self.targets] = target_seqs
            assert len(np_targets) == len(texts)

        feed_dict[self.split_infos] = np.asarray(split_infos, dtype=np.int32)
        feed_dict[self.speaker_embeddings] = [
            np.load(f) for f in embed_filenames
        ]

        if self.gta or not hparams.predict_linear:
            mels, alignments, stop_tokens = self.session.run(
                [
                    self.mel_outputs, self.alignments,
                    self.stop_token_prediction
                ],
                feed_dict=feed_dict)
            #Linearize outputs (1D arrays)
            mels = [mel for gpu_mels in mels for mel in gpu_mels]
            alignments = [
                align for gpu_aligns in alignments for align in gpu_aligns
            ]
            stop_tokens = [
                token for gpu_token in stop_tokens for token in gpu_token
            ]

            if not self.gta:
                #Natural batch synthesis
                #Get Mel lengths for the entire batch from stop_tokens predictions
                target_lengths = self._get_output_lengths(stop_tokens)

            #Take off the batch wise padding
            mels = [
                mel[:target_length, :]
                for mel, target_length in zip(mels, target_lengths)
            ]
            assert len(mels) == len(texts)

        else:
            linears, mels, alignments, stop_tokens = self.session.run(
                [
                    self.linear_outputs, self.mel_outputs, self.alignments,
                    self.stop_token_prediction
                ],
                feed_dict=feed_dict)
            #Linearize outputs (1D arrays)
            linears = [
                linear for gpu_linear in linears for linear in gpu_linear
            ]
            mels = [mel for gpu_mels in mels for mel in gpu_mels]
            alignments = [
                align for gpu_aligns in alignments for align in gpu_aligns
            ]
            stop_tokens = [
                token for gpu_token in stop_tokens for token in gpu_token
            ]

            #Natural batch synthesis
            #Get Mel/Linear lengths for the entire batch from stop_tokens predictions
            # target_lengths = self._get_output_lengths(stop_tokens)
            target_lengths = [9999]

            #Take off the batch wise padding
            mels = [
                mel[:target_length, :]
                for mel, target_length in zip(mels, target_lengths)
            ]
            linears = [
                linear[:target_length, :]
                for linear, target_length in zip(linears, target_lengths)
            ]
            assert len(mels) == len(linears) == len(texts)

        if basenames is None:
            raise NotImplemented()

        saved_mels_paths = []
        for i, mel in enumerate(mels):
            # Write the spectrogram to disk
            # Note: outputs mel-spectrogram files and target ones have same names, just different folders
            mel_filename = os.path.join(out_dir,
                                        "mel-{}.npy".format(basenames[i]))
            np.save(mel_filename, mel, allow_pickle=False)
            saved_mels_paths.append(mel_filename)

            if log_dir is not None:
                #save wav (mel -> wav)
                wav = audio.inv_mel_spectrogram(mel.T, hparams)
                audio.save_wav(wav,
                               os.path.join(
                                   log_dir,
                                   "wavs/wav-{}-mel.wav".format(basenames[i])),
                               sr=hparams.sample_rate)

                #save alignments
                plot.plot_alignment(alignments[i],
                                    os.path.join(
                                        log_dir,
                                        "plots/alignment-{}.png".format(
                                            basenames[i])),
                                    title="{}".format(texts[i]),
                                    split_title=True,
                                    max_len=target_lengths[i])

                #save mel spectrogram plot
                plot.plot_spectrogram(
                    mel,
                    os.path.join(log_dir,
                                 "plots/mel-{}.png".format(basenames[i])),
                    title="{}".format(texts[i]),
                    split_title=True)

                if hparams.predict_linear:
                    #save wav (linear -> wav)
                    wav = audio.inv_linear_spectrogram(linears[i].T, hparams)
                    audio.save_wav(wav,
                                   os.path.join(
                                       log_dir,
                                       "wavs/wav-{}-linear.wav".format(
                                           basenames[i])),
                                   sr=hparams.sample_rate)

                    #save linear spectrogram plot
                    plot.plot_spectrogram(linears[i],
                                          os.path.join(
                                              log_dir,
                                              "plots/linear-{}.png".format(
                                                  basenames[i])),
                                          title="{}".format(texts[i]),
                                          split_title=True,
                                          auto_aspect=True)

        return saved_mels_paths
Пример #4
0
def train(log_dir, args, hparams):
    save_dir = os.path.join(log_dir, "taco_pretrained")
    plot_dir = os.path.join(log_dir, "plots")
    wav_dir = os.path.join(log_dir, "wavs")
    mel_dir = os.path.join(log_dir, "mel-spectrograms")
    eval_dir = os.path.join(log_dir, "eval-dir")
    eval_plot_dir = os.path.join(eval_dir, "plots")
    eval_wav_dir = os.path.join(eval_dir, "wavs")
    tensorboard_dir = os.path.join(log_dir, "tacotron_events")
    os.makedirs(save_dir, exist_ok=True)
    os.makedirs(plot_dir, exist_ok=True)
    os.makedirs(wav_dir, exist_ok=True)
    os.makedirs(mel_dir, exist_ok=True)
    os.makedirs(eval_dir, exist_ok=True)
    os.makedirs(eval_plot_dir, exist_ok=True)
    os.makedirs(eval_wav_dir, exist_ok=True)
    os.makedirs(tensorboard_dir, exist_ok=True)

    checkpoint_fpath = os.path.join(save_dir, "tacotron_model.ckpt")

    log("Checkpoint path: {}".format(checkpoint_fpath))
    log("Using model: Tacotron")
    log(hparams_debug_string())

    # Start by setting a seed for repeatability
    tf.set_random_seed(hparams.tacotron_random_seed)

    # Set up data feeder
    coord = tf.train.Coordinator()
    with tf.variable_scope("datafeeder") as scope:
        feeder = Feeder(coord, hparams)

    # Set up model:
    global_step = tf.Variable(0, name="global_step", trainable=False)
    model, stats = model_train_mode(args, feeder, hparams, global_step)
    #eval_model = model_test_mode(args, feeder, hparams, global_step)

    # Book keeping
    step = 0
    time_window = ValueWindow(100)
    loss_window = ValueWindow(100)
    saver = tf.train.Saver(max_to_keep=2)

    log("Tacotron training set to a maximum of {} steps".format(
        args.tacotron_train_steps))

    # Memory allocation on the GPU as needed
    config = tf.ConfigProto()
    config.gpu_options.allow_growth = True
    config.allow_soft_placement = True

    # Train
    with tf.Session(config=config) as sess:
        try:
            summary_writer = tf.summary.FileWriter(tensorboard_dir, sess.graph)

            sess.run(tf.global_variables_initializer())

            # saved model restoring
            if args.restore:
                # Restore saved model if the user requested it, default = True
                try:
                    checkpoint_state = tf.train.get_checkpoint_state(save_dir)

                    if checkpoint_state and checkpoint_state.model_checkpoint_path:
                        log("Loading checkpoint {}".format(
                            checkpoint_state.model_checkpoint_path),
                            slack=True)
                        saver.restore(sess,
                                      checkpoint_state.model_checkpoint_path)

                    else:
                        log("No model to load at {}".format(save_dir),
                            slack=True)
                        saver.save(sess,
                                   checkpoint_fpath,
                                   global_step=global_step)

                except tf.errors.OutOfRangeError as e:
                    log("Cannot restore checkpoint: {}".format(e), slack=True)
            else:
                log("Starting new training!", slack=True)
                saver.save(sess, checkpoint_fpath, global_step=global_step)

            # initializing feeder
            feeder.start_threads(sess)
            print("Feeder is intialized and model is ready to train.......")

            # Training loop
            while not coord.should_stop() and step < args.tacotron_train_steps:
                start_time = time.time()
                step, loss, opt = sess.run(
                    [global_step, model.loss, model.optimize])
                time_window.append(time.time() - start_time)
                loss_window.append(loss)
                message = "Step {:7d} [{:.3f} sec/step, loss={:.5f}, avg_loss={:.5f}]".format(
                    step, time_window.average, loss, loss_window.average)
                log(message,
                    end="\r",
                    slack=(step % args.checkpoint_interval == 0))
                print(message)

                if loss > 100 or np.isnan(loss):
                    log("Loss exploded to {:.5f} at step {}".format(
                        loss, step))
                    raise Exception("Loss exploded")

                if step % args.summary_interval == 0:
                    log("\nWriting summary at step {}".format(step))
                    summary_writer.add_summary(sess.run(stats), step)

                if step % args.eval_interval == 0:
                    pass


                if step % args.checkpoint_interval == 0 or step == args.tacotron_train_steps or \
                        step == 300:
                    # Save model and current global step
                    saver.save(sess, checkpoint_fpath, global_step=global_step)

                    log("\nSaving alignment, Mel-Spectrograms and griffin-lim inverted waveform.."
                        )
                    input_seq, mel_prediction, alignment, target, target_length = sess.run(
                        [
                            model.tower_inputs[0][0],
                            model.tower_mel_outputs[0][0],
                            model.tower_alignments[0][0],
                            model.tower_mel_targets[0][0],
                            model.tower_targets_lengths[0][0],
                        ])

                    # save predicted mel spectrogram to disk (debug)
                    mel_filename = "mel-prediction-step-{}.npy".format(step)
                    np.save(os.path.join(mel_dir, mel_filename),
                            mel_prediction.T,
                            allow_pickle=False)

                    # save griffin lim inverted wav for debug (mel -> wav)
                    wav = audio.inv_mel_spectrogram(mel_prediction.T, hparams)
                    audio.save_wav(
                        wav,
                        os.path.join(wav_dir,
                                     "step-{}-wave-from-mel.wav".format(step)),
                        sr=hparams.sample_rate)

                    # save alignment plot to disk (control purposes)
                    plot.plot_alignment(
                        alignment,
                        os.path.join(plot_dir,
                                     "step-{}-align.png".format(step)),
                        title="{}, {}, step={}, loss={:.5f}".format(
                            "Tacotron", time_string(), step, loss),
                        max_len=target_length // hparams.outputs_per_step)
                    # save real and predicted mel-spectrogram plot to disk (control purposes)
                    plot.plot_spectrogram(
                        mel_prediction,
                        os.path.join(
                            plot_dir,
                            "step-{}-mel-spectrogram.png".format(step)),
                        title="{}, {}, step={}, loss={:.5f}".format(
                            "Tacotron", time_string(), step, loss),
                        target_spectrogram=target,
                        max_len=target_length)

                if step % args.embedding_interval == 0 or step == args.tacotron_train_steps or step == 1:
                    # Get current checkpoint state
                    checkpoint_state = tf.train.get_checkpoint_state(save_dir)

            log("Tacotron training complete after {} global steps!".format(
                args.tacotron_train_steps),
                slack=True)
            return save_dir

        except Exception as e:
            log("Exiting due to exception: {}".format(e), slack=True)
            traceback.print_exc()
            coord.request_stop(e)