Need help training Speech2Text from scratch
I am currently trying to train aSpeech2Textmodel from scratch but what I am seeing during training is odd…For some reason the word-error-rate (WER) is already quite good… 50% or less after thefirststep, which simply cannot be right…The WER then increases as the model progressively returns more and more garbage.Clearly, there is something wrong with the way I am training the model.Can somebody help me find out what I’m doing wrong here or point me to an example that explains how to do this right?This is how I am initializing theSeq2SeqTrainerand theSpeech2TextForConditionalGeneration:training_args = Seq2SeqTrainingArguments(
    output_dir=out_dir,
    evaluation_strategy=IntervalStrategy("steps"),
    save_steps=save_and_eval_steps,
    eval_steps=save_and_eval_steps,
    num_train_epochs=3,
    per_device_train_batch_size=16,
    per_device_eval_batch_size=64,
    warmup_steps=500,
    weight_decay=0.01,
    logging_dir=log_dir,
    group_by_length=True,
    load_best_model_at_end=True,
    save_total_limit=2,
)

# Create the model
config = Speech2TextConfig(
    return_dict=True,
    sampling_rate=sampling_rate,
    vocab_size=tokenizer.vocab_size,
    pad_token_id=processor.tokenizer.pad_token_id,
    bos_token_id=processor.tokenizer.bos_token_id,
    eos_token_id=processor.tokenizer.eos_token_id,
    decoder_start_token_id=processor.tokenizer.bos_token_id,
)

model = Speech2TextForConditionalGeneration(config)
model.train()

trainer = Seq2SeqTrainer(
    model=model,
    args=training_args,
    train_dataset=train_dataset,
    eval_dataset=eval_dataset,
    data_collator=Speech2TextCollator(processor=processor),
    compute_metrics=partial(compute_metrics, processor),
    callbacks=[EarlyStoppingCallback(early_stopping_patience=early_stopping_patience)],
)

last_checkpoint = trainer_utils.get_last_checkpoint(out_dir)
trainer.train(resume_from_checkpoint=last_checkpoint)The other important thing is probably what the input to the model is. So, the data collator does the following:@dataclass
class Speech2TextCollator:

    def __init__(self, processor: Speech2TextProcessor):
        self.processor = processor

    def __call__(self, features: List[Dict[str, Union[List[int], torch.Tensor]]]) -> Dict[str, torch.Tensor]:
        inputs = [torch.Tensor(f["inputs"]) for f in features]
        targets = [torch.Tensor(f["targets"]) for f in features]
        # Create batches
        inputs_batch = pad_sequence(inputs, batch_first=True)
        targets_batch = pad_sequence(targets, batch_first=True).long()
        attention_mask = pad_sequence([f["attention_mask"] for f in features], batch_first=True).long()
        return dict(
            input_features=inputs_batch,
            attention_mask=attention_mask,
            labels=targets_batch
        )Less relevant is how I am computing the WER:def compute_metrics(processor: Speech2TextProcessor, pred):
    # pred_logits = pred.predictions
    pred_ids = np.argmax(pred.predictions[0], axis=-1)
    pred_str = processor.batch_decode(pred_ids)

    # we do not want to group tokens when computing the metrics
    label_str = processor.batch_decode(pred.label_ids, group_tokens=False)

    wer = error_rate(targets=label_str, predictions=pred_str, tokens="words")
    cer = error_rate(targets=label_str, predictions=pred_str, tokens="characters")

    return {"wer": wer, "cer": cer}The output during the training looks something like this:{'eval_loss': 6.661579608917236, 'eval_wer': 0.5277777777777778, 'eval_cer': 0.37888198757763975, 'eval_runtime': 0.1115, 'eval_samples_per_second': 26.916, 'eval_steps_per_second': 8.972, 'epoch': 0.11}
                                                                                
{'eval_loss': 6.655572414398193, 'eval_wer': 0.5833333333333334, 'eval_cer': 0.40993788819875776, 'eval_runtime': 0.0951, 'eval_samples_per_second': 31.544, 'eval_steps_per_second': 10.515, 'epoch': 0.11}

{'eval_loss': 6.649582386016846, 'eval_wer': 0.6111111111111112, 'eval_cer': 0.453416149068323, 'eval_runtime': 0.0953, 'eval_samples_per_second': 31.472, 'eval_steps_per_second': 10.491, 'epoch': 0.12}        

{'eval_loss': 6.643609523773193, 'eval_wer': 0.6111111111111112, 'eval_cer': 0.453416149068323, 'eval_runtime': 0.1001, 'eval_samples_per_second': 29.982, 'eval_steps_per_second': 9.994, 'epoch': 0.12}
                                                                              
{'eval_loss': 6.637502193450928, 'eval_wer': 0.6388888888888888, 'eval_cer': 0.4658385093167702, 'eval_runtime': 0.1108, 'eval_samples_per_second': 27.085, 'eval_steps_per_second': 9.028, 'epoch': 0.12}
                                                                             
{'eval_loss': 6.631495952606201, 'eval_wer': 0.6388888888888888, 'eval_cer': 0.4658385093167702, 'eval_runtime': 0.1021, 'eval_samples_per_second': 29.372, 'eval_steps_per_second': 9.791, 'epoch': 0.12}
                                                                             
{'eval_loss': 6.6251702308654785, 'eval_wer': 0.6944444444444444, 'eval_cer': 0.4906832298136646, 'eval_runtime': 0.1079, 'eval_samples_per_second': 27.795, 'eval_steps_per_second': 9.265, 'epoch': 0.12}
                                                                       
{'eval_loss': 6.618703365325928, 'eval_wer': 0.6944444444444444, 'eval_cer': 0.4906832298136646, 'eval_runtime': 0.1041, 'eval_samples_per_second': 28.821, 'eval_steps_per_second': 9.607, 'epoch': 0.12}
                                                                           
{'eval_loss': 6.612504959106445, 'eval_wer': 0.6944444444444444, 'eval_cer': 0.4906832298136646, 'eval_runtime': 0.0946, 'eval_samples_per_second': 31.709, 'eval_steps_per_second': 10.57, 'epoch': 0.13}
                                                                        
{'eval_loss': 6.606250286102295, 'eval_wer': 0.6944444444444444, 'eval_cer': 0.5031055900621118, 'eval_runtime': 0.1131, 'eval_samples_per_second': 26.526, 'eval_steps_per_second': 8.842, 'epoch': 0.13}
                                                                             
{'eval_loss': 6.6001152992248535, 'eval_wer': 0.7222222222222222, 'eval_cer': 0.546583850931677, 'eval_runtime': 0.1143, 'eval_samples_per_second': 26.242, 'eval_steps_per_second': 8.747, 'epoch': 0.13}
                                                                        
{'eval_loss': 6.594000339508057, 'eval_wer': 0.7222222222222222, 'eval_cer': 0.546583850931677, 'eval_runtime': 0.1058, 'eval_samples_per_second': 28.356, 'eval_steps_per_second': 9.452, 'epoch': 0.13}
                                                                        
{'eval_loss': 6.587998867034912, 'eval_wer': 0.7777777777777778, 'eval_cer': 0.6211180124223602, 'eval_runtime': 0.1148, 'eval_samples_per_second': 26.138, 'eval_steps_per_second': 8.713, 'epoch': 0.13}
                                                                        
{'eval_loss': 6.582004070281982, 'eval_wer': 0.8055555555555556, 'eval_cer': 0.6956521739130435, 'eval_runtime': 0.1031, 'eval_samples_per_second': 29.1, 'eval_steps_per_second': 9.7, 'epoch': 0.13}