support Wan-FLF2V (#11353)

* update transformer

---------
Co-authored-by: Aryan <aryan@huggingface.co>

docs/source/en/api/pipelines/wan.md

@@ -133,6 +133,60 @@ output = pipe(
 export_to_video(output, "wan-i2v.mp4", fps=16)
 ```
 
+### First and Last Frame Interpolation
+
+```python
+import numpy as np
+import torch
+import torchvision.transforms.functional as TF
+from diffusers import AutoencoderKLWan, WanImageToVideoPipeline
+from diffusers.utils import export_to_video, load_image
+from transformers import CLIPVisionModel
+
+
+model_id = "Wan-AI/Wan2.1-FLF2V-14B-720P-diffusers"
+image_encoder = CLIPVisionModel.from_pretrained(model_id, subfolder="image_encoder", torch_dtype=torch.float32)
+vae = AutoencoderKLWan.from_pretrained(model_id, subfolder="vae", torch_dtype=torch.float32)
+pipe = WanImageToVideoPipeline.from_pretrained(
+    model_id, vae=vae, image_encoder=image_encoder, torch_dtype=torch.bfloat16
+)
+pipe.to("cuda")
+
+first_frame = load_image("https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/flf2v_input_first_frame.png")
+last_frame = load_image("https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/flf2v_input_last_frame.png")
+
+def aspect_ratio_resize(image, pipe, max_area=720 * 1280):
+    aspect_ratio = image.height / image.width
+    mod_value = pipe.vae_scale_factor_spatial * pipe.transformer.config.patch_size[1]
+    height = round(np.sqrt(max_area * aspect_ratio)) // mod_value * mod_value
+    width = round(np.sqrt(max_area / aspect_ratio)) // mod_value * mod_value
+    image = image.resize((width, height))
+    return image, height, width
+
+def center_crop_resize(image, height, width):
+    # Calculate resize ratio to match first frame dimensions
+    resize_ratio = max(width / image.width, height / image.height)
+    
+    # Resize the image
+    width = round(image.width * resize_ratio)
+    height = round(image.height * resize_ratio)
+    size = [width, height]
+    image = TF.center_crop(image, size)
+    
+    return image, height, width
+
+first_frame, height, width = aspect_ratio_resize(first_frame, pipe)
+if last_frame.size != first_frame.size:
+    last_frame, _, _ = center_crop_resize(last_frame, height, width)
+
+prompt = "CG animation style, a small blue bird takes off from the ground, flapping its wings. The bird's feathers are delicate, with a unique pattern on its chest. The background shows a blue sky with white clouds under bright sunshine. The camera follows the bird upward, capturing its flight and the vastness of the sky from a close-up, low-angle perspective."
+
+output = pipe(
+    image=first_frame, last_image=last_frame, prompt=prompt, height=height, width=width, guidance_scale=5.5
+).frames[0]
+export_to_video(output, "output.mp4", fps=16)
+```
+
 ### Video to Video Generation
 
 ```python

scripts/convert_wan_to_diffusers.py

@@ -39,6 +39,24 @@ TRANSFORMER_KEYS_RENAME_DICT = {
     "img_emb.proj.1": "condition_embedder.image_embedder.ff.net.0.proj",
     "img_emb.proj.3": "condition_embedder.image_embedder.ff.net.2",
     "img_emb.proj.4": "condition_embedder.image_embedder.norm2",
+    # for the FLF2V model
+    "img_emb.emb_pos": "condition_embedder.image_embedder.pos_embed",
+    # Add attention component mappings
+    "self_attn.q": "attn1.to_q",
+    "self_attn.k": "attn1.to_k",
+    "self_attn.v": "attn1.to_v",
+    "self_attn.o": "attn1.to_out.0",
+    "self_attn.norm_q": "attn1.norm_q",
+    "self_attn.norm_k": "attn1.norm_k",
+    "cross_attn.q": "attn2.to_q",
+    "cross_attn.k": "attn2.to_k",
+    "cross_attn.v": "attn2.to_v",
+    "cross_attn.o": "attn2.to_out.0",
+    "cross_attn.norm_q": "attn2.norm_q",
+    "cross_attn.norm_k": "attn2.norm_k",
+    "attn2.to_k_img": "attn2.add_k_proj",
+    "attn2.to_v_img": "attn2.add_v_proj",
+    "attn2.norm_k_img": "attn2.norm_added_k",
 }
 
 TRANSFORMER_SPECIAL_KEYS_REMAP = {}
@@ -135,6 +153,28 @@ def get_transformer_config(model_type: str) -> Dict[str, Any]:
                 "text_dim": 4096,
             },
         }
+    elif model_type == "Wan-FLF2V-14B-720P":
+        config = {
+            "model_id": "ypyp/Wan2.1-FLF2V-14B-720P",  # This is just a placeholder
+            "diffusers_config": {
+                "image_dim": 1280,
+                "added_kv_proj_dim": 5120,
+                "attention_head_dim": 128,
+                "cross_attn_norm": True,
+                "eps": 1e-06,
+                "ffn_dim": 13824,
+                "freq_dim": 256,
+                "in_channels": 36,
+                "num_attention_heads": 40,
+                "num_layers": 40,
+                "out_channels": 16,
+                "patch_size": [1, 2, 2],
+                "qk_norm": "rms_norm_across_heads",
+                "text_dim": 4096,
+                "rope_max_seq_len": 1024,
+                "pos_embed_seq_len": 257 * 2,
+            },
+        }
     return config
 
 
@@ -397,7 +437,7 @@ if __name__ == "__main__":
         prediction_type="flow_prediction", use_flow_sigmas=True, num_train_timesteps=1000, flow_shift=3.0
     )
 
-    if "I2V" in args.model_type:
+    if "I2V" in args.model_type or "FLF2V" in args.model_type:
         image_encoder = CLIPVisionModelWithProjection.from_pretrained(
             "laion/CLIP-ViT-H-14-laion2B-s32B-b79K", torch_dtype=torch.bfloat16
         )

src/diffusers/models/transformers/transformer_wan.py

@@ -49,8 +49,10 @@ class WanAttnProcessor2_0:
     ) -> torch.Tensor:
         encoder_hidden_states_img = None
         if attn.add_k_proj is not None:
-            encoder_hidden_states_img = encoder_hidden_states[:, :257]
-            encoder_hidden_states = encoder_hidden_states[:, 257:]
+            # 512 is the context length of the text encoder, hardcoded for now
+            image_context_length = encoder_hidden_states.shape[1] - 512
+            encoder_hidden_states_img = encoder_hidden_states[:, :image_context_length]
+            encoder_hidden_states = encoder_hidden_states[:, image_context_length:]
         if encoder_hidden_states is None:
             encoder_hidden_states = hidden_states
 
@@ -108,14 +110,23 @@ class WanAttnProcessor2_0:
 
 
 class WanImageEmbedding(torch.nn.Module):
-    def __init__(self, in_features: int, out_features: int):
+    def __init__(self, in_features: int, out_features: int, pos_embed_seq_len=None):
         super().__init__()
 
         self.norm1 = FP32LayerNorm(in_features)
         self.ff = FeedForward(in_features, out_features, mult=1, activation_fn="gelu")
         self.norm2 = FP32LayerNorm(out_features)
+        if pos_embed_seq_len is not None:
+            self.pos_embed = nn.Parameter(torch.zeros(1, pos_embed_seq_len, in_features))
+        else:
+            self.pos_embed = None
 
     def forward(self, encoder_hidden_states_image: torch.Tensor) -> torch.Tensor:
+        if self.pos_embed is not None:
+            batch_size, seq_len, embed_dim = encoder_hidden_states_image.shape
+            encoder_hidden_states_image = encoder_hidden_states_image.view(-1, 2 * seq_len, embed_dim)
+            encoder_hidden_states_image = encoder_hidden_states_image + self.pos_embed
+
         hidden_states = self.norm1(encoder_hidden_states_image)
         hidden_states = self.ff(hidden_states)
         hidden_states = self.norm2(hidden_states)
@@ -130,6 +141,7 @@ class WanTimeTextImageEmbedding(nn.Module):
         time_proj_dim: int,
         text_embed_dim: int,
         image_embed_dim: Optional[int] = None,
+        pos_embed_seq_len: Optional[int] = None,
     ):
         super().__init__()
 
@@ -141,7 +153,7 @@ class WanTimeTextImageEmbedding(nn.Module):
 
         self.image_embedder = None
         if image_embed_dim is not None:
-            self.image_embedder = WanImageEmbedding(image_embed_dim, dim)
+            self.image_embedder = WanImageEmbedding(image_embed_dim, dim, pos_embed_seq_len=pos_embed_seq_len)
 
     def forward(
         self,
@@ -350,6 +362,7 @@ class WanTransformer3DModel(ModelMixin, ConfigMixin, PeftAdapterMixin, FromOrigi
         image_dim: Optional[int] = None,
         added_kv_proj_dim: Optional[int] = None,
         rope_max_seq_len: int = 1024,
+        pos_embed_seq_len: Optional[int] = None,
     ) -> None:
         super().__init__()
 
@@ -368,6 +381,7 @@ class WanTransformer3DModel(ModelMixin, ConfigMixin, PeftAdapterMixin, FromOrigi
             time_proj_dim=inner_dim * 6,
             text_embed_dim=text_dim,
             image_embed_dim=image_dim,
+            pos_embed_seq_len=pos_embed_seq_len,
         )
 
         # 3. Transformer blocks

src/diffusers/pipelines/wan/pipeline_wan_i2v.py

@@ -380,6 +380,7 @@ class WanImageToVideoPipeline(DiffusionPipeline, WanLoraLoaderMixin):
         device: Optional[torch.device] = None,
         generator: Optional[Union[torch.Generator, List[torch.Generator]]] = None,
         latents: Optional[torch.Tensor] = None,
+        last_image: Optional[torch.Tensor] = None,
     ) -> Tuple[torch.Tensor, torch.Tensor]:
         num_latent_frames = (num_frames - 1) // self.vae_scale_factor_temporal + 1
         latent_height = height // self.vae_scale_factor_spatial
@@ -398,9 +399,16 @@ class WanImageToVideoPipeline(DiffusionPipeline, WanLoraLoaderMixin):
             latents = latents.to(device=device, dtype=dtype)
 
         image = image.unsqueeze(2)
+        if last_image is None:
             video_condition = torch.cat(
                 [image, image.new_zeros(image.shape[0], image.shape[1], num_frames - 1, height, width)], dim=2
             )
+        else:
+            last_image = last_image.unsqueeze(2)
+            video_condition = torch.cat(
+                [image, image.new_zeros(image.shape[0], image.shape[1], num_frames - 2, height, width), last_image],
+                dim=2,
+            )
         video_condition = video_condition.to(device=device, dtype=dtype)
 
         latents_mean = (
@@ -424,7 +432,11 @@ class WanImageToVideoPipeline(DiffusionPipeline, WanLoraLoaderMixin):
         latent_condition = (latent_condition - latents_mean) * latents_std
 
         mask_lat_size = torch.ones(batch_size, 1, num_frames, latent_height, latent_width)
+
+        if last_image is None:
             mask_lat_size[:, :, list(range(1, num_frames))] = 0
+        else:
+            mask_lat_size[:, :, list(range(1, num_frames - 1))] = 0
         first_frame_mask = mask_lat_size[:, :, 0:1]
         first_frame_mask = torch.repeat_interleave(first_frame_mask, dim=2, repeats=self.vae_scale_factor_temporal)
         mask_lat_size = torch.concat([first_frame_mask, mask_lat_size[:, :, 1:, :]], dim=2)
@@ -476,6 +488,7 @@ class WanImageToVideoPipeline(DiffusionPipeline, WanLoraLoaderMixin):
         prompt_embeds: Optional[torch.Tensor] = None,
         negative_prompt_embeds: Optional[torch.Tensor] = None,
         image_embeds: Optional[torch.Tensor] = None,
+        last_image: Optional[torch.Tensor] = None,
         output_type: Optional[str] = "np",
         return_dict: bool = True,
         attention_kwargs: Optional[Dict[str, Any]] = None,
@@ -620,7 +633,10 @@ class WanImageToVideoPipeline(DiffusionPipeline, WanLoraLoaderMixin):
             negative_prompt_embeds = negative_prompt_embeds.to(transformer_dtype)
 
         if image_embeds is None:
+            if last_image is None:
                 image_embeds = self.encode_image(image, device)
+            else:
+                image_embeds = self.encode_image([image, last_image], device)
         image_embeds = image_embeds.repeat(batch_size, 1, 1)
         image_embeds = image_embeds.to(transformer_dtype)
 
@@ -631,6 +647,10 @@ class WanImageToVideoPipeline(DiffusionPipeline, WanLoraLoaderMixin):
         # 5. Prepare latent variables
         num_channels_latents = self.vae.config.z_dim
         image = self.video_processor.preprocess(image, height=height, width=width).to(device, dtype=torch.float32)
+        if last_image is not None:
+            last_image = self.video_processor.preprocess(last_image, height=height, width=width).to(
+                device, dtype=torch.float32
+            )
         latents, condition = self.prepare_latents(
             image,
             batch_size * num_videos_per_prompt,
@@ -642,6 +662,7 @@ class WanImageToVideoPipeline(DiffusionPipeline, WanLoraLoaderMixin):
             device,
             generator,
             latents,
+            last_image,
         )
 
         # 6. Denoising loop

tests/pipelines/wan/test_wan_image_to_video.py

@@ -160,3 +160,90 @@ class WanImageToVideoPipelineFastTests(PipelineTesterMixin, unittest.TestCase):
     @unittest.skip("TODO: revisit failing as it requires a very high threshold to pass")
     def test_inference_batch_single_identical(self):
         pass
+
+
+class WanFLFToVideoPipelineFastTests(WanImageToVideoPipelineFastTests):
+    def get_dummy_components(self):
+        torch.manual_seed(0)
+        vae = AutoencoderKLWan(
+            base_dim=3,
+            z_dim=16,
+            dim_mult=[1, 1, 1, 1],
+            num_res_blocks=1,
+            temperal_downsample=[False, True, True],
+        )
+
+        torch.manual_seed(0)
+        # TODO: impl FlowDPMSolverMultistepScheduler
+        scheduler = FlowMatchEulerDiscreteScheduler(shift=7.0)
+        text_encoder = T5EncoderModel.from_pretrained("hf-internal-testing/tiny-random-t5")
+        tokenizer = AutoTokenizer.from_pretrained("hf-internal-testing/tiny-random-t5")
+
+        torch.manual_seed(0)
+        transformer = WanTransformer3DModel(
+            patch_size=(1, 2, 2),
+            num_attention_heads=2,
+            attention_head_dim=12,
+            in_channels=36,
+            out_channels=16,
+            text_dim=32,
+            freq_dim=256,
+            ffn_dim=32,
+            num_layers=2,
+            cross_attn_norm=True,
+            qk_norm="rms_norm_across_heads",
+            rope_max_seq_len=32,
+            image_dim=4,
+            pos_embed_seq_len=2 * (4 * 4 + 1),
+        )
+
+        torch.manual_seed(0)
+        image_encoder_config = CLIPVisionConfig(
+            hidden_size=4,
+            projection_dim=4,
+            num_hidden_layers=2,
+            num_attention_heads=2,
+            image_size=4,
+            intermediate_size=16,
+            patch_size=1,
+        )
+        image_encoder = CLIPVisionModelWithProjection(image_encoder_config)
+
+        torch.manual_seed(0)
+        image_processor = CLIPImageProcessor(crop_size=4, size=4)
+
+        components = {
+            "transformer": transformer,
+            "vae": vae,
+            "scheduler": scheduler,
+            "text_encoder": text_encoder,
+            "tokenizer": tokenizer,
+            "image_encoder": image_encoder,
+            "image_processor": image_processor,
+        }
+        return components
+
+    def get_dummy_inputs(self, device, seed=0):
+        if str(device).startswith("mps"):
+            generator = torch.manual_seed(seed)
+        else:
+            generator = torch.Generator(device=device).manual_seed(seed)
+        image_height = 16
+        image_width = 16
+        image = Image.new("RGB", (image_width, image_height))
+        last_image = Image.new("RGB", (image_width, image_height))
+        inputs = {
+            "image": image,
+            "last_image": last_image,
+            "prompt": "dance monkey",
+            "negative_prompt": "negative",
+            "height": image_height,
+            "width": image_width,
+            "generator": generator,
+            "num_inference_steps": 2,
+            "guidance_scale": 6.0,
+            "num_frames": 9,
+            "max_sequence_length": 16,
+            "output_type": "pt",
+        }
+        return inputs