add possibility to have audio_output_lengths (#91)

Author: ylacombe

parler_tts/modeling_parler_tts.py

@@ -3511,6 +3511,7 @@ def generate(
                 output_ids,
                 audio_scales=audio_scales,
             ).audio_values.squeeze(1)
+            output_lengths = [audio.shape[0] for audio in output_values]
         else:
             output_values = []
             for sample_id in range(batch_size):
@@ -3522,13 +3523,14 @@ def generate(
                     output_values.append(sample.transpose(0, 2))
                 else:
                     output_values.append(torch.zeros((1, 1, 1)).to(self.device))
-            # TODO: we should keep track of output length as well. Not really straightforward tbh
+            output_lengths = [audio.shape[0] for audio in output_values]
             output_values = (
                 torch.nn.utils.rnn.pad_sequence(output_values, batch_first=True, padding_value=0)
                 .squeeze(-1)
                 .squeeze(-1)
             )
         if generation_config.return_dict_in_generate:
+            outputs["audios_length"] = output_lengths
             outputs.sequences = output_values
             return outputs
         else: