[transducer] refine forward args to dict (#2245)

wenet/transducer/transducer.py

@@ -92,20 +92,16 @@ def __init__(
 
     def forward(
         self,
-        speech: torch.Tensor,
-        speech_lengths: torch.Tensor,
-        text: torch.Tensor,
-        text_lengths: torch.Tensor,
-        steps: int = 0,
+        batch: dict,
+        device: torch.device,
     ) -> Dict[str, Optional[torch.Tensor]]:
         """Frontend + Encoder + predictor + joint + loss
-
-        Args:
-            speech: (Batch, Length, ...)
-            speech_lengths: (Batch, )
-            text: (Batch, Length)
-            text_lengths: (Batch,)
         """
+        speech = batch['feats'].to(device)
+        speech_lengths = batch['feats_lengths'].to(device)
+        text = batch['target'].to(device)
+        text_lengths = batch['target_lengths'].to(device)
+        steps = batch.get('steps', 0)
         assert text_lengths.dim() == 1, text_lengths.shape
         # Check that batch_size is unified
         assert (speech.shape[0] == speech_lengths.shape[0] == text.shape[0] ==