[DC-AE] support tiling for DC-AE (#10510)

* autoencoder_dc tiling

* add tiling and slicing support in SANA pipelines

* create variables for padding length because the line becomes too long

* add tiling and slicing support in pag SANA pipelines

* revert changes to tile size

* make style

* add vae tiling test

---------

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

src/diffusers/models/autoencoders/autoencoder_dc.py

@@ -486,6 +486,9 @@ class AutoencoderDC(ModelMixin, ConfigMixin, FromOriginalModelMixin):
         self.tile_sample_stride_height = 448
         self.tile_sample_stride_width = 448
 
+        self.tile_latent_min_height = self.tile_sample_min_height // self.spatial_compression_ratio
+        self.tile_latent_min_width = self.tile_sample_min_width // self.spatial_compression_ratio
+
     def enable_tiling(
         self,
         tile_sample_min_height: Optional[int] = None,
@@ -515,6 +518,8 @@ class AutoencoderDC(ModelMixin, ConfigMixin, FromOriginalModelMixin):
         self.tile_sample_min_width = tile_sample_min_width or self.tile_sample_min_width
         self.tile_sample_stride_height = tile_sample_stride_height or self.tile_sample_stride_height
         self.tile_sample_stride_width = tile_sample_stride_width or self.tile_sample_stride_width
+        self.tile_latent_min_height = self.tile_sample_min_height // self.spatial_compression_ratio
+        self.tile_latent_min_width = self.tile_sample_min_width // self.spatial_compression_ratio
 
     def disable_tiling(self) -> None:
         r"""
@@ -606,11 +611,106 @@ class AutoencoderDC(ModelMixin, ConfigMixin, FromOriginalModelMixin):
             return (decoded,)
         return DecoderOutput(sample=decoded)
 
+    def blend_v(self, a: torch.Tensor, b: torch.Tensor, blend_extent: int) -> torch.Tensor:
+        blend_extent = min(a.shape[2], b.shape[2], blend_extent)
+        for y in range(blend_extent):
+            b[:, :, y, :] = a[:, :, -blend_extent + y, :] * (1 - y / blend_extent) + b[:, :, y, :] * (y / blend_extent)
+        return b
+
+    def blend_h(self, a: torch.Tensor, b: torch.Tensor, blend_extent: int) -> torch.Tensor:
+        blend_extent = min(a.shape[3], b.shape[3], blend_extent)
+        for x in range(blend_extent):
+            b[:, :, :, x] = a[:, :, :, -blend_extent + x] * (1 - x / blend_extent) + b[:, :, :, x] * (x / blend_extent)
+        return b
+
     def tiled_encode(self, x: torch.Tensor, return_dict: bool = True) -> torch.Tensor:
-        raise NotImplementedError("`tiled_encode` has not been implemented for AutoencoderDC.")
+        batch_size, num_channels, height, width = x.shape
+        latent_height = height // self.spatial_compression_ratio
+        latent_width = width // self.spatial_compression_ratio
+
+        tile_latent_min_height = self.tile_sample_min_height // self.spatial_compression_ratio
+        tile_latent_min_width = self.tile_sample_min_width // self.spatial_compression_ratio
+        tile_latent_stride_height = self.tile_sample_stride_height // self.spatial_compression_ratio
+        tile_latent_stride_width = self.tile_sample_stride_width // self.spatial_compression_ratio
+        blend_height = tile_latent_min_height - tile_latent_stride_height
+        blend_width = tile_latent_min_width - tile_latent_stride_width
+
+        # Split x into overlapping tiles and encode them separately.
+        # The tiles have an overlap to avoid seams between tiles.
+        rows = []
+        for i in range(0, x.shape[2], self.tile_sample_stride_height):
+            row = []
+            for j in range(0, x.shape[3], self.tile_sample_stride_width):
+                tile = x[:, :, i : i + self.tile_sample_min_height, j : j + self.tile_sample_min_width]
+                if (
+                    tile.shape[2] % self.spatial_compression_ratio != 0
+                    or tile.shape[3] % self.spatial_compression_ratio != 0
+                ):
+                    pad_h = (self.spatial_compression_ratio - tile.shape[2]) % self.spatial_compression_ratio
+                    pad_w = (self.spatial_compression_ratio - tile.shape[3]) % self.spatial_compression_ratio
+                    tile = F.pad(tile, (0, pad_w, 0, pad_h))
+                tile = self.encoder(tile)
+                row.append(tile)
+            rows.append(row)
+        result_rows = []
+        for i, row in enumerate(rows):
+            result_row = []
+            for j, tile in enumerate(row):
+                # blend the above tile and the left tile
+                # to the current tile and add the current tile to the result row
+                if i > 0:
+                    tile = self.blend_v(rows[i - 1][j], tile, blend_height)
+                if j > 0:
+                    tile = self.blend_h(row[j - 1], tile, blend_width)
+                result_row.append(tile[:, :, :tile_latent_stride_height, :tile_latent_stride_width])
+            result_rows.append(torch.cat(result_row, dim=3))
+
+        encoded = torch.cat(result_rows, dim=2)[:, :, :latent_height, :latent_width]
+
+        if not return_dict:
+            return (encoded,)
+        return EncoderOutput(latent=encoded)
 
     def tiled_decode(self, z: torch.Tensor, return_dict: bool = True) -> Union[DecoderOutput, torch.Tensor]:
-        raise NotImplementedError("`tiled_decode` has not been implemented for AutoencoderDC.")
+        batch_size, num_channels, height, width = z.shape
+
+        tile_latent_min_height = self.tile_sample_min_height // self.spatial_compression_ratio
+        tile_latent_min_width = self.tile_sample_min_width // self.spatial_compression_ratio
+        tile_latent_stride_height = self.tile_sample_stride_height // self.spatial_compression_ratio
+        tile_latent_stride_width = self.tile_sample_stride_width // self.spatial_compression_ratio
+
+        blend_height = self.tile_sample_min_height - self.tile_sample_stride_height
+        blend_width = self.tile_sample_min_width - self.tile_sample_stride_width
+
+        # Split z into overlapping tiles and decode them separately.
+        # The tiles have an overlap to avoid seams between tiles.
+        rows = []
+        for i in range(0, height, tile_latent_stride_height):
+            row = []
+            for j in range(0, width, tile_latent_stride_width):
+                tile = z[:, :, i : i + tile_latent_min_height, j : j + tile_latent_min_width]
+                decoded = self.decoder(tile)
+                row.append(decoded)
+            rows.append(row)
+
+        result_rows = []
+        for i, row in enumerate(rows):
+            result_row = []
+            for j, tile in enumerate(row):
+                # blend the above tile and the left tile
+                # to the current tile and add the current tile to the result row
+                if i > 0:
+                    tile = self.blend_v(rows[i - 1][j], tile, blend_height)
+                if j > 0:
+                    tile = self.blend_h(row[j - 1], tile, blend_width)
+                result_row.append(tile[:, :, : self.tile_sample_stride_height, : self.tile_sample_stride_width])
+            result_rows.append(torch.cat(result_row, dim=3))
+
+        decoded = torch.cat(result_rows, dim=2)
+
+        if not return_dict:
+            return (decoded,)
+        return DecoderOutput(sample=decoded)
 
     def forward(self, sample: torch.Tensor, return_dict: bool = True) -> torch.Tensor:
         encoded = self.encode(sample, return_dict=False)[0]

src/diffusers/pipelines/pag/pipeline_pag_sana.py

@@ -183,6 +183,35 @@ class SanaPAGPipeline(DiffusionPipeline, PAGMixin):
             pag_attn_processors=(PAGCFGSanaLinearAttnProcessor2_0(), PAGIdentitySanaLinearAttnProcessor2_0()),
         )
 
+    def enable_vae_slicing(self):
+        r"""
+        Enable sliced VAE decoding. When this option is enabled, the VAE will split the input tensor in slices to
+        compute decoding in several steps. This is useful to save some memory and allow larger batch sizes.
+        """
+        self.vae.enable_slicing()
+
+    def disable_vae_slicing(self):
+        r"""
+        Disable sliced VAE decoding. If `enable_vae_slicing` was previously enabled, this method will go back to
+        computing decoding in one step.
+        """
+        self.vae.disable_slicing()
+
+    def enable_vae_tiling(self):
+        r"""
+        Enable tiled VAE decoding. When this option is enabled, the VAE will split the input tensor into tiles to
+        compute decoding and encoding in several steps. This is useful for saving a large amount of memory and to allow
+        processing larger images.
+        """
+        self.vae.enable_tiling()
+
+    def disable_vae_tiling(self):
+        r"""
+        Disable tiled VAE decoding. If `enable_vae_tiling` was previously enabled, this method will go back to
+        computing decoding in one step.
+        """
+        self.vae.disable_tiling()
+
     def encode_prompt(
         self,
         prompt: Union[str, List[str]],

src/diffusers/pipelines/sana/pipeline_sana.py

@@ -218,6 +218,35 @@ class SanaPipeline(DiffusionPipeline, SanaLoraLoaderMixin):
         )
         self.image_processor = PixArtImageProcessor(vae_scale_factor=self.vae_scale_factor)
 
+    def enable_vae_slicing(self):
+        r"""
+        Enable sliced VAE decoding. When this option is enabled, the VAE will split the input tensor in slices to
+        compute decoding in several steps. This is useful to save some memory and allow larger batch sizes.
+        """
+        self.vae.enable_slicing()
+
+    def disable_vae_slicing(self):
+        r"""
+        Disable sliced VAE decoding. If `enable_vae_slicing` was previously enabled, this method will go back to
+        computing decoding in one step.
+        """
+        self.vae.disable_slicing()
+
+    def enable_vae_tiling(self):
+        r"""
+        Enable tiled VAE decoding. When this option is enabled, the VAE will split the input tensor into tiles to
+        compute decoding and encoding in several steps. This is useful for saving a large amount of memory and to allow
+        processing larger images.
+        """
+        self.vae.enable_tiling()
+
+    def disable_vae_tiling(self):
+        r"""
+        Disable tiled VAE decoding. If `enable_vae_tiling` was previously enabled, this method will go back to
+        computing decoding in one step.
+        """
+        self.vae.disable_tiling()
+
     def encode_prompt(
         self,
         prompt: Union[str, List[str]],

tests/pipelines/sana/test_sana.py

@@ -254,6 +254,36 @@ class SanaPipelineFastTests(PipelineTesterMixin, unittest.TestCase):
                 "Attention slicing should not affect the inference results",
             )
 
+    def test_vae_tiling(self, expected_diff_max: float = 0.2):
+        generator_device = "cpu"
+        components = self.get_dummy_components()
+
+        pipe = self.pipeline_class(**components)
+        pipe.to("cpu")
+        pipe.set_progress_bar_config(disable=None)
+
+        # Without tiling
+        inputs = self.get_dummy_inputs(generator_device)
+        inputs["height"] = inputs["width"] = 128
+        output_without_tiling = pipe(**inputs)[0]
+
+        # With tiling
+        pipe.vae.enable_tiling(
+            tile_sample_min_height=96,
+            tile_sample_min_width=96,
+            tile_sample_stride_height=64,
+            tile_sample_stride_width=64,
+        )
+        inputs = self.get_dummy_inputs(generator_device)
+        inputs["height"] = inputs["width"] = 128
+        output_with_tiling = pipe(**inputs)[0]
+
+        self.assertLess(
+            (to_np(output_without_tiling) - to_np(output_with_tiling)).max(),
+            expected_diff_max,
+            "VAE tiling should not affect the inference results",
+        )
+
     # TODO(aryan): Create a dummy gemma model with smol vocab size
     @unittest.skip(
         "A very small vocab size is used for fast tests. So, any kind of prompt other than the empty default used in other tests will lead to a embedding lookup error. This test uses a long prompt that causes the error."