Fix bug that prevented training wan 2.2 with batch size greater than 1

extensions_built_in/diffusion_models/wan22/wan22_model.py

@@ -1,3 +1,4 @@
+from functools import partial
 import torch
 from toolkit.prompt_utils import PromptEmbeds
 from PIL import Image
@@ -55,6 +56,29 @@ scheduler_config = {
     "use_dynamic_shifting": False,
 }
 
+# TODO: this is a temporary monkeypatch to fix the time text embedding to allow for batch sizes greater than 1. Remove this when the diffusers library is fixed.
+def time_text_monkeypatch(
+    self,
+    timestep: torch.Tensor,
+    encoder_hidden_states,
+    encoder_hidden_states_image = None,
+    timestep_seq_len = None,
+):
+    timestep = self.timesteps_proj(timestep)
+    if timestep_seq_len is not None:
+        timestep = timestep.unflatten(0, (encoder_hidden_states.shape[0], timestep_seq_len))
+
+    time_embedder_dtype = next(iter(self.time_embedder.parameters())).dtype
+    if timestep.dtype != time_embedder_dtype and time_embedder_dtype != torch.int8:
+        timestep = timestep.to(time_embedder_dtype)
+    temb = self.time_embedder(timestep).type_as(encoder_hidden_states)
+    timestep_proj = self.time_proj(self.act_fn(temb))
+
+    encoder_hidden_states = self.text_embedder(encoder_hidden_states)
+    if encoder_hidden_states_image is not None:
+        encoder_hidden_states_image = self.image_embedder(encoder_hidden_states_image)
+
+    return temb, timestep_proj, encoder_hidden_states, encoder_hidden_states_image
 
 class Wan22Model(Wan21):
     arch = "wan22_5b"
@@ -81,6 +105,12 @@ class Wan22Model(Wan21):
 
         self._wan_cache = None
     
+    def load_model(self):
+        super().load_model()
+        
+        # patch the condition embedder
+        self.model.condition_embedder.forward = partial(time_text_monkeypatch, self.model.condition_embedder)
+
     def get_bucket_divisibility(self):
         # 16x compression  and 2x2 patch size
         return 32