LTX 0.9.5 (#10968)

* update


---------
Co-authored-by: YiYi Xu <yixu310@gmail.com>
Co-authored-by: hlky <hlky@hlky.ac>

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

@@ -196,6 +196,12 @@ export_to_video(video, "ship.mp4", fps=24)
   - all
   - __call__
 
+## LTXConditionPipeline
+
+[[autodoc]] LTXConditionPipeline
+  - all
+  - __call__
+
 ## LTXPipelineOutput
 
 [[autodoc]] pipelines.ltx.pipeline_output.LTXPipelineOutput

scripts/convert_ltx_to_diffusers.py

@@ -74,6 +74,32 @@ VAE_091_RENAME_DICT = {
     "last_scale_shift_table": "scale_shift_table",
 }
 
+VAE_095_RENAME_DICT = {
+    # decoder
+    "up_blocks.0": "mid_block",
+    "up_blocks.1": "up_blocks.0.upsamplers.0",
+    "up_blocks.2": "up_blocks.0",
+    "up_blocks.3": "up_blocks.1.upsamplers.0",
+    "up_blocks.4": "up_blocks.1",
+    "up_blocks.5": "up_blocks.2.upsamplers.0",
+    "up_blocks.6": "up_blocks.2",
+    "up_blocks.7": "up_blocks.3.upsamplers.0",
+    "up_blocks.8": "up_blocks.3",
+    # encoder
+    "down_blocks.0": "down_blocks.0",
+    "down_blocks.1": "down_blocks.0.downsamplers.0",
+    "down_blocks.2": "down_blocks.1",
+    "down_blocks.3": "down_blocks.1.downsamplers.0",
+    "down_blocks.4": "down_blocks.2",
+    "down_blocks.5": "down_blocks.2.downsamplers.0",
+    "down_blocks.6": "down_blocks.3",
+    "down_blocks.7": "down_blocks.3.downsamplers.0",
+    "down_blocks.8": "mid_block",
+    # common
+    "last_time_embedder": "time_embedder",
+    "last_scale_shift_table": "scale_shift_table",
+}
+
 VAE_SPECIAL_KEYS_REMAP = {
     "per_channel_statistics.channel": remove_keys_,
     "per_channel_statistics.mean-of-means": remove_keys_,
@@ -81,10 +107,6 @@ VAE_SPECIAL_KEYS_REMAP = {
     "model.diffusion_model": remove_keys_,
 }
 
-VAE_091_SPECIAL_KEYS_REMAP = {
-    "timestep_scale_multiplier": remove_keys_,
-}
-
 
 def get_state_dict(saved_dict: Dict[str, Any]) -> Dict[str, Any]:
     state_dict = saved_dict
@@ -104,12 +126,16 @@ def update_state_dict_inplace(state_dict: Dict[str, Any], old_key: str, new_key:
 def convert_transformer(
     ckpt_path: str,
     dtype: torch.dtype,
+    version: str = "0.9.0",
 ):
     PREFIX_KEY = "model.diffusion_model."
 
     original_state_dict = get_state_dict(load_file(ckpt_path))
+    config = {}
+    if version == "0.9.5":
+        config["_use_causal_rope_fix"] = True
     with init_empty_weights():
-        transformer = LTXVideoTransformer3DModel()
+        transformer = LTXVideoTransformer3DModel(**config)
 
     for key in list(original_state_dict.keys()):
         new_key = key[:]
@@ -161,12 +187,19 @@ def get_vae_config(version: str) -> Dict[str, Any]:
             "out_channels": 3,
             "latent_channels": 128,
             "block_out_channels": (128, 256, 512, 512),
+            "down_block_types": (
+                "LTXVideoDownBlock3D",
+                "LTXVideoDownBlock3D",
+                "LTXVideoDownBlock3D",
+                "LTXVideoDownBlock3D",
+            ),
             "decoder_block_out_channels": (128, 256, 512, 512),
             "layers_per_block": (4, 3, 3, 3, 4),
             "decoder_layers_per_block": (4, 3, 3, 3, 4),
             "spatio_temporal_scaling": (True, True, True, False),
             "decoder_spatio_temporal_scaling": (True, True, True, False),
             "decoder_inject_noise": (False, False, False, False, False),
+            "downsample_type": ("conv", "conv", "conv", "conv"),
             "upsample_residual": (False, False, False, False),
             "upsample_factor": (1, 1, 1, 1),
             "patch_size": 4,
@@ -183,12 +216,19 @@ def get_vae_config(version: str) -> Dict[str, Any]:
             "out_channels": 3,
             "latent_channels": 128,
             "block_out_channels": (128, 256, 512, 512),
+            "down_block_types": (
+                "LTXVideoDownBlock3D",
+                "LTXVideoDownBlock3D",
+                "LTXVideoDownBlock3D",
+                "LTXVideoDownBlock3D",
+            ),
             "decoder_block_out_channels": (256, 512, 1024),
             "layers_per_block": (4, 3, 3, 3, 4),
             "decoder_layers_per_block": (5, 6, 7, 8),
             "spatio_temporal_scaling": (True, True, True, False),
             "decoder_spatio_temporal_scaling": (True, True, True),
             "decoder_inject_noise": (True, True, True, False),
+            "downsample_type": ("conv", "conv", "conv", "conv"),
             "upsample_residual": (True, True, True),
             "upsample_factor": (2, 2, 2),
             "timestep_conditioning": True,
@@ -200,7 +240,38 @@ def get_vae_config(version: str) -> Dict[str, Any]:
             "decoder_causal": False,
         }
         VAE_KEYS_RENAME_DICT.update(VAE_091_RENAME_DICT)
-        VAE_SPECIAL_KEYS_REMAP.update(VAE_091_SPECIAL_KEYS_REMAP)
+    elif version == "0.9.5":
+        config = {
+            "in_channels": 3,
+            "out_channels": 3,
+            "latent_channels": 128,
+            "block_out_channels": (128, 256, 512, 1024, 2048),
+            "down_block_types": (
+                "LTXVideo095DownBlock3D",
+                "LTXVideo095DownBlock3D",
+                "LTXVideo095DownBlock3D",
+                "LTXVideo095DownBlock3D",
+            ),
+            "decoder_block_out_channels": (256, 512, 1024),
+            "layers_per_block": (4, 6, 6, 2, 2),
+            "decoder_layers_per_block": (5, 5, 5, 5),
+            "spatio_temporal_scaling": (True, True, True, True),
+            "decoder_spatio_temporal_scaling": (True, True, True),
+            "decoder_inject_noise": (False, False, False, False),
+            "downsample_type": ("spatial", "temporal", "spatiotemporal", "spatiotemporal"),
+            "upsample_residual": (True, True, True),
+            "upsample_factor": (2, 2, 2),
+            "timestep_conditioning": True,
+            "patch_size": 4,
+            "patch_size_t": 1,
+            "resnet_norm_eps": 1e-6,
+            "scaling_factor": 1.0,
+            "encoder_causal": True,
+            "decoder_causal": False,
+            "spatial_compression_ratio": 32,
+            "temporal_compression_ratio": 8,
+        }
+        VAE_KEYS_RENAME_DICT.update(VAE_095_RENAME_DICT)
     return config
 
 
@@ -223,7 +294,7 @@ def get_args():
     parser.add_argument("--output_path", type=str, required=True, help="Path where converted model should be saved")
     parser.add_argument("--dtype", default="fp32", help="Torch dtype to save the model in.")
     parser.add_argument(
-        "--version", type=str, default="0.9.0", choices=["0.9.0", "0.9.1"], help="Version of the LTX model"
+        "--version", type=str, default="0.9.0", choices=["0.9.0", "0.9.1", "0.9.5"], help="Version of the LTX model"
     )
     return parser.parse_args()
 
@@ -277,14 +348,17 @@ if __name__ == "__main__":
         for param in text_encoder.parameters():
             param.data = param.data.contiguous()
 
-        scheduler = FlowMatchEulerDiscreteScheduler(
-            use_dynamic_shifting=True,
-            base_shift=0.95,
-            max_shift=2.05,
-            base_image_seq_len=1024,
-            max_image_seq_len=4096,
-            shift_terminal=0.1,
-        )
+        if args.version == "0.9.5":
+            scheduler = FlowMatchEulerDiscreteScheduler(use_dynamic_shifting=False)
+        else:
+            scheduler = FlowMatchEulerDiscreteScheduler(
+                use_dynamic_shifting=True,
+                base_shift=0.95,
+                max_shift=2.05,
+                base_image_seq_len=1024,
+                max_image_seq_len=4096,
+                shift_terminal=0.1,
+            )
 
         pipe = LTXPipeline(
             scheduler=scheduler,

src/diffusers/__init__.py

@@ -402,6 +402,7 @@ else:
             "LDMTextToImagePipeline",
             "LEditsPPPipelineStableDiffusion",
             "LEditsPPPipelineStableDiffusionXL",
+            "LTXConditionPipeline",
             "LTXImageToVideoPipeline",
             "LTXPipeline",
             "Lumina2Pipeline",
@@ -947,6 +948,7 @@ if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
             LDMTextToImagePipeline,
             LEditsPPPipelineStableDiffusion,
             LEditsPPPipelineStableDiffusionXL,
+            LTXConditionPipeline,
             LTXImageToVideoPipeline,
             LTXPipeline,
             Lumina2Pipeline,

src/diffusers/models/autoencoders/autoencoder_kl_ltx.py

@@ -196,6 +196,55 @@ class LTXVideoResnetBlock3d(nn.Module):
         return hidden_states
 
 
+class LTXVideoDownsampler3d(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        stride: Union[int, Tuple[int, int, int]] = 1,
+        is_causal: bool = True,
+        padding_mode: str = "zeros",
+    ) -> None:
+        super().__init__()
+
+        self.stride = stride if isinstance(stride, tuple) else (stride, stride, stride)
+        self.group_size = (in_channels * stride[0] * stride[1] * stride[2]) // out_channels
+
+        out_channels = out_channels // (self.stride[0] * self.stride[1] * self.stride[2])
+
+        self.conv = LTXVideoCausalConv3d(
+            in_channels=in_channels,
+            out_channels=out_channels,
+            kernel_size=3,
+            stride=1,
+            is_causal=is_causal,
+            padding_mode=padding_mode,
+        )
+
+    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
+        hidden_states = torch.cat([hidden_states[:, :, : self.stride[0] - 1], hidden_states], dim=2)
+
+        residual = (
+            hidden_states.unflatten(4, (-1, self.stride[2]))
+            .unflatten(3, (-1, self.stride[1]))
+            .unflatten(2, (-1, self.stride[0]))
+        )
+        residual = residual.permute(0, 1, 3, 5, 7, 2, 4, 6).flatten(1, 4)
+        residual = residual.unflatten(1, (-1, self.group_size))
+        residual = residual.mean(dim=2)
+
+        hidden_states = self.conv(hidden_states)
+        hidden_states = (
+            hidden_states.unflatten(4, (-1, self.stride[2]))
+            .unflatten(3, (-1, self.stride[1]))
+            .unflatten(2, (-1, self.stride[0]))
+        )
+        hidden_states = hidden_states.permute(0, 1, 3, 5, 7, 2, 4, 6).flatten(1, 4)
+        hidden_states = hidden_states + residual
+
+        return hidden_states
+
+
 class LTXVideoUpsampler3d(nn.Module):
     def __init__(
         self,
@@ -204,6 +253,7 @@ class LTXVideoUpsampler3d(nn.Module):
         is_causal: bool = True,
         residual: bool = False,
         upscale_factor: int = 1,
+        padding_mode: str = "zeros",
     ) -> None:
         super().__init__()
 
@@ -219,6 +269,7 @@ class LTXVideoUpsampler3d(nn.Module):
             kernel_size=3,
             stride=1,
             is_causal=is_causal,
+            padding_mode=padding_mode,
         )
 
     def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
@@ -352,6 +403,118 @@ class LTXVideoDownBlock3D(nn.Module):
         return hidden_states
 
 
+class LTXVideo095DownBlock3D(nn.Module):
+    r"""
+    Down block used in the LTXVideo model.
+
+    Args:
+        in_channels (`int`):
+            Number of input channels.
+        out_channels (`int`, *optional*):
+            Number of output channels. If None, defaults to `in_channels`.
+        num_layers (`int`, defaults to `1`):
+            Number of resnet layers.
+        dropout (`float`, defaults to `0.0`):
+            Dropout rate.
+        resnet_eps (`float`, defaults to `1e-6`):
+            Epsilon value for normalization layers.
+        resnet_act_fn (`str`, defaults to `"swish"`):
+            Activation function to use.
+        spatio_temporal_scale (`bool`, defaults to `True`):
+            Whether or not to use a downsampling layer. If not used, output dimension would be same as input dimension.
+            Whether or not to downsample across temporal dimension.
+        is_causal (`bool`, defaults to `True`):
+            Whether this layer behaves causally (future frames depend only on past frames) or not.
+    """
+
+    _supports_gradient_checkpointing = True
+
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: Optional[int] = None,
+        num_layers: int = 1,
+        dropout: float = 0.0,
+        resnet_eps: float = 1e-6,
+        resnet_act_fn: str = "swish",
+        spatio_temporal_scale: bool = True,
+        is_causal: bool = True,
+        downsample_type: str = "conv",
+    ):
+        super().__init__()
+
+        out_channels = out_channels or in_channels
+
+        resnets = []
+        for _ in range(num_layers):
+            resnets.append(
+                LTXVideoResnetBlock3d(
+                    in_channels=in_channels,
+                    out_channels=in_channels,
+                    dropout=dropout,
+                    eps=resnet_eps,
+                    non_linearity=resnet_act_fn,
+                    is_causal=is_causal,
+                )
+            )
+        self.resnets = nn.ModuleList(resnets)
+
+        self.downsamplers = None
+        if spatio_temporal_scale:
+            self.downsamplers = nn.ModuleList()
+
+            if downsample_type == "conv":
+                self.downsamplers.append(
+                    LTXVideoCausalConv3d(
+                        in_channels=in_channels,
+                        out_channels=in_channels,
+                        kernel_size=3,
+                        stride=(2, 2, 2),
+                        is_causal=is_causal,
+                    )
+                )
+            elif downsample_type == "spatial":
+                self.downsamplers.append(
+                    LTXVideoDownsampler3d(
+                        in_channels=in_channels, out_channels=out_channels, stride=(1, 2, 2), is_causal=is_causal
+                    )
+                )
+            elif downsample_type == "temporal":
+                self.downsamplers.append(
+                    LTXVideoDownsampler3d(
+                        in_channels=in_channels, out_channels=out_channels, stride=(2, 1, 1), is_causal=is_causal
+                    )
+                )
+            elif downsample_type == "spatiotemporal":
+                self.downsamplers.append(
+                    LTXVideoDownsampler3d(
+                        in_channels=in_channels, out_channels=out_channels, stride=(2, 2, 2), is_causal=is_causal
+                    )
+                )
+
+        self.gradient_checkpointing = False
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        temb: Optional[torch.Tensor] = None,
+        generator: Optional[torch.Generator] = None,
+    ) -> torch.Tensor:
+        r"""Forward method of the `LTXDownBlock3D` class."""
+
+        for i, resnet in enumerate(self.resnets):
+            if torch.is_grad_enabled() and self.gradient_checkpointing:
+                hidden_states = self._gradient_checkpointing_func(resnet, hidden_states, temb, generator)
+            else:
+                hidden_states = resnet(hidden_states, temb, generator)
+
+        if self.downsamplers is not None:
+            for downsampler in self.downsamplers:
+                hidden_states = downsampler(hidden_states)
+
+        return hidden_states
+
+
 # Adapted from diffusers.models.autoencoders.autoencoder_kl_cogvideox.CogVideoMidBlock3d
 class LTXVideoMidBlock3d(nn.Module):
     r"""
@@ -593,8 +756,15 @@ class LTXVideoEncoder3d(nn.Module):
         in_channels: int = 3,
         out_channels: int = 128,
         block_out_channels: Tuple[int, ...] = (128, 256, 512, 512),
+        down_block_types: Tuple[str, ...] = (
+            "LTXVideoDownBlock3D",
+            "LTXVideoDownBlock3D",
+            "LTXVideoDownBlock3D",
+            "LTXVideoDownBlock3D",
+        ),
         spatio_temporal_scaling: Tuple[bool, ...] = (True, True, True, False),
         layers_per_block: Tuple[int, ...] = (4, 3, 3, 3, 4),
+        downsample_type: Tuple[str, ...] = ("conv", "conv", "conv", "conv"),
         patch_size: int = 4,
         patch_size_t: int = 1,
         resnet_norm_eps: float = 1e-6,
@@ -617,20 +787,37 @@ class LTXVideoEncoder3d(nn.Module):
         )
 
         # down blocks
-        num_block_out_channels = len(block_out_channels)
+        is_ltx_095 = down_block_types[-1] == "LTXVideo095DownBlock3D"
+        num_block_out_channels = len(block_out_channels) - (1 if is_ltx_095 else 0)
         self.down_blocks = nn.ModuleList([])
         for i in range(num_block_out_channels):
             input_channel = output_channel
-            output_channel = block_out_channels[i + 1] if i + 1 < num_block_out_channels else block_out_channels[i]
-
-            down_block = LTXVideoDownBlock3D(
-                in_channels=input_channel,
-                out_channels=output_channel,
-                num_layers=layers_per_block[i],
-                resnet_eps=resnet_norm_eps,
-                spatio_temporal_scale=spatio_temporal_scaling[i],
-                is_causal=is_causal,
-            )
+            if not is_ltx_095:
+                output_channel = block_out_channels[i + 1] if i + 1 < num_block_out_channels else block_out_channels[i]
+            else:
+                output_channel = block_out_channels[i + 1]
+
+            if down_block_types[i] == "LTXVideoDownBlock3D":
+                down_block = LTXVideoDownBlock3D(
+                    in_channels=input_channel,
+                    out_channels=output_channel,
+                    num_layers=layers_per_block[i],
+                    resnet_eps=resnet_norm_eps,
+                    spatio_temporal_scale=spatio_temporal_scaling[i],
+                    is_causal=is_causal,
+                )
+            elif down_block_types[i] == "LTXVideo095DownBlock3D":
+                down_block = LTXVideo095DownBlock3D(
+                    in_channels=input_channel,
+                    out_channels=output_channel,
+                    num_layers=layers_per_block[i],
+                    resnet_eps=resnet_norm_eps,
+                    spatio_temporal_scale=spatio_temporal_scaling[i],
+                    is_causal=is_causal,
+                    downsample_type=downsample_type[i],
+                )
+            else:
+                raise ValueError(f"Unknown down block type: {down_block_types[i]}")
 
             self.down_blocks.append(down_block)
 
@@ -794,7 +981,9 @@ class LTXVideoDecoder3d(nn.Module):
         # timestep embedding
         self.time_embedder = None
         self.scale_shift_table = None
+        self.timestep_scale_multiplier = None
         if timestep_conditioning:
+            self.timestep_scale_multiplier = nn.Parameter(torch.tensor(1000.0, dtype=torch.float32))
             self.time_embedder = PixArtAlphaCombinedTimestepSizeEmbeddings(output_channel * 2, 0)
             self.scale_shift_table = nn.Parameter(torch.randn(2, output_channel) / output_channel**0.5)
 
@@ -803,6 +992,9 @@ class LTXVideoDecoder3d(nn.Module):
     def forward(self, hidden_states: torch.Tensor, temb: Optional[torch.Tensor] = None) -> torch.Tensor:
         hidden_states = self.conv_in(hidden_states)
 
+        if self.timestep_scale_multiplier is not None:
+            temb = temb * self.timestep_scale_multiplier
+
         if torch.is_grad_enabled() and self.gradient_checkpointing:
             hidden_states = self._gradient_checkpointing_func(self.mid_block, hidden_states, temb)
 
@@ -891,12 +1083,19 @@ class AutoencoderKLLTXVideo(ModelMixin, ConfigMixin, FromOriginalModelMixin):
         out_channels: int = 3,
         latent_channels: int = 128,
         block_out_channels: Tuple[int, ...] = (128, 256, 512, 512),
+        down_block_types: Tuple[str, ...] = (
+            "LTXVideoDownBlock3D",
+            "LTXVideoDownBlock3D",
+            "LTXVideoDownBlock3D",
+            "LTXVideoDownBlock3D",
+        ),
         decoder_block_out_channels: Tuple[int, ...] = (128, 256, 512, 512),
         layers_per_block: Tuple[int, ...] = (4, 3, 3, 3, 4),
         decoder_layers_per_block: Tuple[int, ...] = (4, 3, 3, 3, 4),
         spatio_temporal_scaling: Tuple[bool, ...] = (True, True, True, False),
         decoder_spatio_temporal_scaling: Tuple[bool, ...] = (True, True, True, False),
         decoder_inject_noise: Tuple[bool, ...] = (False, False, False, False, False),
+        downsample_type: Tuple[str, ...] = ("conv", "conv", "conv", "conv"),
         upsample_residual: Tuple[bool, ...] = (False, False, False, False),
         upsample_factor: Tuple[int, ...] = (1, 1, 1, 1),
         timestep_conditioning: bool = False,
@@ -906,6 +1105,8 @@ class AutoencoderKLLTXVideo(ModelMixin, ConfigMixin, FromOriginalModelMixin):
         scaling_factor: float = 1.0,
         encoder_causal: bool = True,
         decoder_causal: bool = False,
+        spatial_compression_ratio: int = None,
+        temporal_compression_ratio: int = None,
     ) -> None:
         super().__init__()
 
@@ -913,8 +1114,10 @@ class AutoencoderKLLTXVideo(ModelMixin, ConfigMixin, FromOriginalModelMixin):
             in_channels=in_channels,
             out_channels=latent_channels,
             block_out_channels=block_out_channels,
+            down_block_types=down_block_types,
             spatio_temporal_scaling=spatio_temporal_scaling,
             layers_per_block=layers_per_block,
+            downsample_type=downsample_type,
             patch_size=patch_size,
             patch_size_t=patch_size_t,
             resnet_norm_eps=resnet_norm_eps,
@@ -941,8 +1144,16 @@ class AutoencoderKLLTXVideo(ModelMixin, ConfigMixin, FromOriginalModelMixin):
         self.register_buffer("latents_mean", latents_mean, persistent=True)
         self.register_buffer("latents_std", latents_std, persistent=True)
 
-        self.spatial_compression_ratio = patch_size * 2 ** sum(spatio_temporal_scaling)
-        self.temporal_compression_ratio = patch_size_t * 2 ** sum(spatio_temporal_scaling)
+        self.spatial_compression_ratio = (
+            patch_size * 2 ** sum(spatio_temporal_scaling)
+            if spatial_compression_ratio is None
+            else spatial_compression_ratio
+        )
+        self.temporal_compression_ratio = (
+            patch_size_t * 2 ** sum(spatio_temporal_scaling)
+            if temporal_compression_ratio is None
+            else temporal_compression_ratio
+        )
 
         # When decoding a batch of video latents at a time, one can save memory by slicing across the batch dimension
         # to perform decoding of a single video latent at a time.

src/diffusers/models/transformers/transformer_ltx.py

@@ -14,7 +14,7 @@
 # limitations under the License.
 
 import math
-from typing import Any, Dict, Optional, Tuple
+from typing import Any, Dict, Optional, Tuple, Union
 
 import torch
 import torch.nn as nn
@@ -113,20 +113,19 @@ class LTXVideoRotaryPosEmbed(nn.Module):
         self.patch_size_t = patch_size_t
         self.theta = theta
 
-    def forward(
+    def _prepare_video_coords(
         self,
-        hidden_states: torch.Tensor,
+        batch_size: int,
         num_frames: int,
         height: int,
         width: int,
-        rope_interpolation_scale: Optional[Tuple[torch.Tensor, float, float]] = None,
-    ) -> Tuple[torch.Tensor, torch.Tensor]:
-        batch_size = hidden_states.size(0)
-
+        rope_interpolation_scale: Tuple[torch.Tensor, float, float],
+        device: torch.device,
+    ) -> torch.Tensor:
         # Always compute rope in fp32
-        grid_h = torch.arange(height, dtype=torch.float32, device=hidden_states.device)
-        grid_w = torch.arange(width, dtype=torch.float32, device=hidden_states.device)
-        grid_f = torch.arange(num_frames, dtype=torch.float32, device=hidden_states.device)
+        grid_h = torch.arange(height, dtype=torch.float32, device=device)
+        grid_w = torch.arange(width, dtype=torch.float32, device=device)
+        grid_f = torch.arange(num_frames, dtype=torch.float32, device=device)
         grid = torch.meshgrid(grid_f, grid_h, grid_w, indexing="ij")
         grid = torch.stack(grid, dim=0)
         grid = grid.unsqueeze(0).repeat(batch_size, 1, 1, 1, 1)
@@ -138,6 +137,38 @@ class LTXVideoRotaryPosEmbed(nn.Module):
 
         grid = grid.flatten(2, 4).transpose(1, 2)
 
+        return grid
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        num_frames: Optional[int] = None,
+        height: Optional[int] = None,
+        width: Optional[int] = None,
+        rope_interpolation_scale: Optional[Tuple[torch.Tensor, float, float]] = None,
+        video_coords: Optional[torch.Tensor] = None,
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        batch_size = hidden_states.size(0)
+
+        if video_coords is None:
+            grid = self._prepare_video_coords(
+                batch_size,
+                num_frames,
+                height,
+                width,
+                rope_interpolation_scale=rope_interpolation_scale,
+                device=hidden_states.device,
+            )
+        else:
+            grid = torch.stack(
+                [
+                    video_coords[:, 0] / self.base_num_frames,
+                    video_coords[:, 1] / self.base_height,
+                    video_coords[:, 2] / self.base_width,
+                ],
+                dim=-1,
+            )
+
         start = 1.0
         end = self.theta
         freqs = self.theta ** torch.linspace(
@@ -367,10 +398,11 @@ class LTXVideoTransformer3DModel(ModelMixin, ConfigMixin, FromOriginalModelMixin
         encoder_hidden_states: torch.Tensor,
         timestep: torch.LongTensor,
         encoder_attention_mask: torch.Tensor,
-        num_frames: int,
-        height: int,
-        width: int,
-        rope_interpolation_scale: Optional[Tuple[float, float, float]] = None,
+        num_frames: Optional[int] = None,
+        height: Optional[int] = None,
+        width: Optional[int] = None,
+        rope_interpolation_scale: Optional[Union[Tuple[float, float, float], torch.Tensor]] = None,
+        video_coords: Optional[torch.Tensor] = None,
         attention_kwargs: Optional[Dict[str, Any]] = None,
         return_dict: bool = True,
     ) -> torch.Tensor:
@@ -389,7 +421,7 @@ class LTXVideoTransformer3DModel(ModelMixin, ConfigMixin, FromOriginalModelMixin
                     "Passing `scale` via `attention_kwargs` when not using the PEFT backend is ineffective."
                 )
 
-        image_rotary_emb = self.rope(hidden_states, num_frames, height, width, rope_interpolation_scale)
+        image_rotary_emb = self.rope(hidden_states, num_frames, height, width, rope_interpolation_scale, video_coords)
 
         # convert encoder_attention_mask to a bias the same way we do for attention_mask
         if encoder_attention_mask is not None and encoder_attention_mask.ndim == 2:

src/diffusers/pipelines/__init__.py

@@ -264,7 +264,7 @@ else:
         ]
     )
     _import_structure["latte"] = ["LattePipeline"]
-    _import_structure["ltx"] = ["LTXPipeline", "LTXImageToVideoPipeline"]
+    _import_structure["ltx"] = ["LTXPipeline", "LTXImageToVideoPipeline", "LTXConditionPipeline"]
     _import_structure["lumina"] = ["LuminaPipeline", "LuminaText2ImgPipeline"]
     _import_structure["lumina2"] = ["Lumina2Pipeline", "Lumina2Text2ImgPipeline"]
     _import_structure["marigold"].extend(
@@ -618,7 +618,7 @@ if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
             LEditsPPPipelineStableDiffusion,
             LEditsPPPipelineStableDiffusionXL,
         )
-        from .ltx import LTXImageToVideoPipeline, LTXPipeline
+        from .ltx import LTXConditionPipeline, LTXImageToVideoPipeline, LTXPipeline
         from .lumina import LuminaPipeline, LuminaText2ImgPipeline
         from .lumina2 import Lumina2Pipeline, Lumina2Text2ImgPipeline
         from .marigold import (

src/diffusers/pipelines/ltx/__init__.py

@@ -23,6 +23,7 @@ except OptionalDependencyNotAvailable:
     _dummy_objects.update(get_objects_from_module(dummy_torch_and_transformers_objects))
 else:
     _import_structure["pipeline_ltx"] = ["LTXPipeline"]
+    _import_structure["pipeline_ltx_condition"] = ["LTXConditionPipeline"]
     _import_structure["pipeline_ltx_image2video"] = ["LTXImageToVideoPipeline"]
 
 if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
@@ -34,6 +35,7 @@ if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
         from ...utils.dummy_torch_and_transformers_objects import *
     else:
         from .pipeline_ltx import LTXPipeline
+        from .pipeline_ltx_condition import LTXConditionPipeline
         from .pipeline_ltx_image2video import LTXImageToVideoPipeline
 
 else:

src/diffusers/pipelines/ltx/pipeline_ltx.py

@@ -694,9 +694,8 @@ class LTXPipeline(DiffusionPipeline, FromSingleFileMixin, LTXVideoLoraLoaderMixi
         self._num_timesteps = len(timesteps)
 
         # 6. Prepare micro-conditions
-        latent_frame_rate = frame_rate / self.vae_temporal_compression_ratio
         rope_interpolation_scale = (
-            1 / latent_frame_rate,
+            self.vae_temporal_compression_ratio / frame_rate,
             self.vae_spatial_compression_ratio,
             self.vae_spatial_compression_ratio,
         )

src/diffusers/pipelines/ltx/pipeline_ltx_condition.py

+# Copyright 2024 Lightricks and The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import inspect
+from dataclasses import dataclass
+from typing import Any, Callable, Dict, List, Optional, Union
+
+import PIL.Image
+import torch
+from transformers import T5EncoderModel, T5TokenizerFast
+
+from ...callbacks import MultiPipelineCallbacks, PipelineCallback
+from ...image_processor import PipelineImageInput
+from ...loaders import FromSingleFileMixin, LTXVideoLoraLoaderMixin
+from ...models.autoencoders import AutoencoderKLLTXVideo
+from ...models.transformers import LTXVideoTransformer3DModel
+from ...schedulers import FlowMatchEulerDiscreteScheduler
+from ...utils import is_torch_xla_available, logging, replace_example_docstring
+from ...utils.torch_utils import randn_tensor
+from ...video_processor import VideoProcessor
+from ..pipeline_utils import DiffusionPipeline
+from .pipeline_output import LTXPipelineOutput
+
+
+if is_torch_xla_available():
+    import torch_xla.core.xla_model as xm
+
+    XLA_AVAILABLE = True
+else:
+    XLA_AVAILABLE = False
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+EXAMPLE_DOC_STRING = """
+    Examples:
+        ```py
+        >>> import torch
+        >>> from diffusers.pipelines.ltx.pipeline_ltx_condition import LTXConditionPipeline, LTXVideoCondition
+        >>> from diffusers.utils import export_to_video, load_video, load_image
+
+        >>> pipe = LTXConditionPipeline.from_pretrained("Lightricks/LTX-Video-0.9.5", torch_dtype=torch.bfloat16)
+        >>> pipe.to("cuda")
+
+        >>> # Load input image and video
+        >>> video = load_video(
+        ...     "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/cosmos/cosmos-video2world-input-vid.mp4"
+        ... )
+        >>> image = load_image(
+        ...     "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/cosmos/cosmos-video2world-input.jpg"
+        ... )
+
+        >>> # Create conditioning objects
+        >>> condition1 = LTXVideoCondition(
+        ...     image=image,
+        ...     frame_index=0,
+        ... )
+        >>> condition2 = LTXVideoCondition(
+        ...     video=video,
+        ...     frame_index=80,
+        ... )
+
+        >>> prompt = "The video depicts a long, straight highway stretching into the distance, flanked by metal guardrails. The road is divided into multiple lanes, with a few vehicles visible in the far distance. The surrounding landscape features dry, grassy fields on one side and rolling hills on the other. The sky is mostly clear with a few scattered clouds, suggesting a bright, sunny day. And then the camera switch to a winding mountain road covered in snow, with a single vehicle traveling along it. The road is flanked by steep, rocky cliffs and sparse vegetation. The landscape is characterized by rugged terrain and a river visible in the distance. The scene captures the solitude and beauty of a winter drive through a mountainous region."
+        >>> negative_prompt = "worst quality, inconsistent motion, blurry, jittery, distorted"
+
+        >>> # Generate video
+        >>> generator = torch.Generator("cuda").manual_seed(0)
+        >>> video = pipe(
+        ...     conditions=[condition1, condition2],
+        ...     prompt=prompt,
+        ...     negative_prompt=negative_prompt,
+        ...     width=768,
+        ...     height=512,
+        ...     num_frames=161,
+        ...     num_inference_steps=40,
+        ...     generator=generator,
+        ... ).frames[0]
+
+        >>> export_to_video(video, "output.mp4", fps=24)
+        ```
+"""
+
+
+@dataclass
+class LTXVideoCondition:
+    """
+    Defines a single frame-conditioning item for LTX Video - a single frame or a sequence of frames.
+
+    Attributes:
+        image (`PIL.Image.Image`):
+            The image to condition the video on.
+        video (`List[PIL.Image.Image]`):
+            The video to condition the video on.
+        frame_index (`int`):
+            The frame index at which the image or video will conditionally effect the video generation.
+        strength (`float`, defaults to `1.0`):
+            The strength of the conditioning effect. A value of `1.0` means the conditioning effect is fully applied.
+    """
+
+    image: Optional[PIL.Image.Image] = None
+    video: Optional[List[PIL.Image.Image]] = None
+    frame_index: int = 0
+    strength: float = 1.0
+
+
+# from LTX-Video/ltx_video/schedulers/rf.py
+def linear_quadratic_schedule(num_steps, threshold_noise=0.025, linear_steps=None):
+    if linear_steps is None:
+        linear_steps = num_steps // 2
+    if num_steps < 2:
+        return torch.tensor([1.0])
+    linear_sigma_schedule = [i * threshold_noise / linear_steps for i in range(linear_steps)]
+    threshold_noise_step_diff = linear_steps - threshold_noise * num_steps
+    quadratic_steps = num_steps - linear_steps
+    quadratic_coef = threshold_noise_step_diff / (linear_steps * quadratic_steps**2)
+    linear_coef = threshold_noise / linear_steps - 2 * threshold_noise_step_diff / (quadratic_steps**2)
+    const = quadratic_coef * (linear_steps**2)
+    quadratic_sigma_schedule = [
+        quadratic_coef * (i**2) + linear_coef * i + const for i in range(linear_steps, num_steps)
+    ]
+    sigma_schedule = linear_sigma_schedule + quadratic_sigma_schedule + [1.0]
+    sigma_schedule = [1.0 - x for x in sigma_schedule]
+    return torch.tensor(sigma_schedule[:-1])
+
+
+# Copied from diffusers.pipelines.flux.pipeline_flux.calculate_shift
+def calculate_shift(
+    image_seq_len,
+    base_seq_len: int = 256,
+    max_seq_len: int = 4096,
+    base_shift: float = 0.5,
+    max_shift: float = 1.15,
+):
+    m = (max_shift - base_shift) / (max_seq_len - base_seq_len)
+    b = base_shift - m * base_seq_len
+    mu = image_seq_len * m + b
+    return mu
+
+
+# Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.retrieve_timesteps
+def retrieve_timesteps(
+    scheduler,
+    num_inference_steps: Optional[int] = None,
+    device: Optional[Union[str, torch.device]] = None,
+    timesteps: Optional[List[int]] = None,
+    sigmas: Optional[List[float]] = None,
+    **kwargs,
+):
+    r"""
+    Calls the scheduler's `set_timesteps` method and retrieves timesteps from the scheduler after the call. Handles
+    custom timesteps. Any kwargs will be supplied to `scheduler.set_timesteps`.
+
+    Args:
+        scheduler (`SchedulerMixin`):
+            The scheduler to get timesteps from.
+        num_inference_steps (`int`):
+            The number of diffusion steps used when generating samples with a pre-trained model. If used, `timesteps`
+            must be `None`.
+        device (`str` or `torch.device`, *optional*):
+            The device to which the timesteps should be moved to. If `None`, the timesteps are not moved.
+        timesteps (`List[int]`, *optional*):
+            Custom timesteps used to override the timestep spacing strategy of the scheduler. If `timesteps` is passed,
+            `num_inference_steps` and `sigmas` must be `None`.
+        sigmas (`List[float]`, *optional*):
+            Custom sigmas used to override the timestep spacing strategy of the scheduler. If `sigmas` is passed,
+            `num_inference_steps` and `timesteps` must be `None`.
+
+    Returns:
+        `Tuple[torch.Tensor, int]`: A tuple where the first element is the timestep schedule from the scheduler and the
+        second element is the number of inference steps.
+    """
+    if timesteps is not None and sigmas is not None:
+        raise ValueError("Only one of `timesteps` or `sigmas` can be passed. Please choose one to set custom values")
+    if timesteps is not None:
+        accepts_timesteps = "timesteps" in set(inspect.signature(scheduler.set_timesteps).parameters.keys())
+        if not accepts_timesteps:
+            raise ValueError(
+                f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom"
+                f" timestep schedules. Please check whether you are using the correct scheduler."
+            )
+        scheduler.set_timesteps(timesteps=timesteps, device=device, **kwargs)
+        timesteps = scheduler.timesteps
+        num_inference_steps = len(timesteps)
+    elif sigmas is not None:
+        accept_sigmas = "sigmas" in set(inspect.signature(scheduler.set_timesteps).parameters.keys())
+        if not accept_sigmas:
+            raise ValueError(
+                f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom"
+                f" sigmas schedules. Please check whether you are using the correct scheduler."
+            )
+        scheduler.set_timesteps(sigmas=sigmas, device=device, **kwargs)
+        timesteps = scheduler.timesteps
+        num_inference_steps = len(timesteps)
+    else:
+        scheduler.set_timesteps(num_inference_steps, device=device, **kwargs)
+        timesteps = scheduler.timesteps
+    return timesteps, num_inference_steps
+
+
+# Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion_img2img.retrieve_latents
+def retrieve_latents(
+    encoder_output: torch.Tensor, generator: Optional[torch.Generator] = None, sample_mode: str = "sample"
+):
+    if hasattr(encoder_output, "latent_dist") and sample_mode == "sample":
+        return encoder_output.latent_dist.sample(generator)
+    elif hasattr(encoder_output, "latent_dist") and sample_mode == "argmax":
+        return encoder_output.latent_dist.mode()
+    elif hasattr(encoder_output, "latents"):
+        return encoder_output.latents
+    else:
+        raise AttributeError("Could not access latents of provided encoder_output")
+
+
+class LTXConditionPipeline(DiffusionPipeline, FromSingleFileMixin, LTXVideoLoraLoaderMixin):
+    r"""
+    Pipeline for image-to-video generation.
+
+    Reference: https://github.com/Lightricks/LTX-Video
+
+    Args:
+        transformer ([`LTXVideoTransformer3DModel`]):
+            Conditional Transformer architecture to denoise the encoded video latents.
+        scheduler ([`FlowMatchEulerDiscreteScheduler`]):
+            A scheduler to be used in combination with `transformer` to denoise the encoded image latents.
+        vae ([`AutoencoderKLLTXVideo`]):
+            Variational Auto-Encoder (VAE) Model to encode and decode images to and from latent representations.
+        text_encoder ([`T5EncoderModel`]):
+            [T5](https://huggingface.co/docs/transformers/en/model_doc/t5#transformers.T5EncoderModel), specifically
+            the [google/t5-v1_1-xxl](https://huggingface.co/google/t5-v1_1-xxl) variant.
+        tokenizer (`CLIPTokenizer`):
+            Tokenizer of class
+            [CLIPTokenizer](https://huggingface.co/docs/transformers/en/model_doc/clip#transformers.CLIPTokenizer).
+        tokenizer (`T5TokenizerFast`):
+            Second Tokenizer of class
+            [T5TokenizerFast](https://huggingface.co/docs/transformers/en/model_doc/t5#transformers.T5TokenizerFast).
+    """
+
+    model_cpu_offload_seq = "text_encoder->transformer->vae"
+    _optional_components = []
+    _callback_tensor_inputs = ["latents", "prompt_embeds", "negative_prompt_embeds"]
+
+    def __init__(
+        self,
+        scheduler: FlowMatchEulerDiscreteScheduler,
+        vae: AutoencoderKLLTXVideo,
+        text_encoder: T5EncoderModel,
+        tokenizer: T5TokenizerFast,
+        transformer: LTXVideoTransformer3DModel,
+    ):
+        super().__init__()
+
+        self.register_modules(
+            vae=vae,
+            text_encoder=text_encoder,
+            tokenizer=tokenizer,
+            transformer=transformer,
+            scheduler=scheduler,
+        )
+
+        self.vae_spatial_compression_ratio = (
+            self.vae.spatial_compression_ratio if getattr(self, "vae", None) is not None else 32
+        )
+        self.vae_temporal_compression_ratio = (
+            self.vae.temporal_compression_ratio if getattr(self, "vae", None) is not None else 8
+        )
+        self.transformer_spatial_patch_size = (
+            self.transformer.config.patch_size if getattr(self, "transformer", None) is not None else 1
+        )
+        self.transformer_temporal_patch_size = (
+            self.transformer.config.patch_size_t if getattr(self, "transformer") is not None else 1
+        )
+
+        self.video_processor = VideoProcessor(vae_scale_factor=self.vae_spatial_compression_ratio)
+        self.tokenizer_max_length = (
+            self.tokenizer.model_max_length if getattr(self, "tokenizer", None) is not None else 128
+        )
+
+        self.default_height = 512
+        self.default_width = 704
+        self.default_frames = 121
+
+    def _get_t5_prompt_embeds(
+        self,
+        prompt: Union[str, List[str]] = None,
+        num_videos_per_prompt: int = 1,
+        max_sequence_length: int = 256,
+        device: Optional[torch.device] = None,
+        dtype: Optional[torch.dtype] = None,
+    ):
+        device = device or self._execution_device
+        dtype = dtype or self.text_encoder.dtype
+
+        prompt = [prompt] if isinstance(prompt, str) else prompt
+        batch_size = len(prompt)
+
+        text_inputs = self.tokenizer(
+            prompt,
+            padding="max_length",
+            max_length=max_sequence_length,
+            truncation=True,
+            add_special_tokens=True,
+            return_tensors="pt",
+        )
+        text_input_ids = text_inputs.input_ids
+        prompt_attention_mask = text_inputs.attention_mask
+        prompt_attention_mask = prompt_attention_mask.bool().to(device)
+
+        untruncated_ids = self.tokenizer(prompt, padding="longest", return_tensors="pt").input_ids
+
+        if untruncated_ids.shape[-1] >= text_input_ids.shape[-1] and not torch.equal(text_input_ids, untruncated_ids):
+            removed_text = self.tokenizer.batch_decode(untruncated_ids[:, max_sequence_length - 1 : -1])
+            logger.warning(
+                "The following part of your input was truncated because `max_sequence_length` is set to "
+                f" {max_sequence_length} tokens: {removed_text}"
+            )
+
+        prompt_embeds = self.text_encoder(text_input_ids.to(device), attention_mask=prompt_attention_mask)[0]
+        prompt_embeds = prompt_embeds.to(dtype=dtype, device=device)
+
+        # duplicate text embeddings for each generation per prompt, using mps friendly method
+        _, seq_len, _ = prompt_embeds.shape
+        prompt_embeds = prompt_embeds.repeat(1, num_videos_per_prompt, 1)
+        prompt_embeds = prompt_embeds.view(batch_size * num_videos_per_prompt, seq_len, -1)
+
+        prompt_attention_mask = prompt_attention_mask.view(batch_size, -1)
+        prompt_attention_mask = prompt_attention_mask.repeat(num_videos_per_prompt, 1)
+
+        return prompt_embeds, prompt_attention_mask
+
+    # Copied from diffusers.pipelines.mochi.pipeline_mochi.MochiPipeline.encode_prompt
+    def encode_prompt(
+        self,
+        prompt: Union[str, List[str]],
+        negative_prompt: Optional[Union[str, List[str]]] = None,
+        do_classifier_free_guidance: bool = True,
+        num_videos_per_prompt: int = 1,
+        prompt_embeds: Optional[torch.Tensor] = None,
+        negative_prompt_embeds: Optional[torch.Tensor] = None,
+        prompt_attention_mask: Optional[torch.Tensor] = None,
+        negative_prompt_attention_mask: Optional[torch.Tensor] = None,
+        max_sequence_length: int = 256,
+        device: Optional[torch.device] = None,
+        dtype: Optional[torch.dtype] = None,
+    ):
+        r"""
+        Encodes the prompt into text encoder hidden states.
+
+        Args:
+            prompt (`str` or `List[str]`, *optional*):
+                prompt to be encoded
+            negative_prompt (`str` or `List[str]`, *optional*):
+                The prompt or prompts not to guide the image generation. If not defined, one has to pass
+                `negative_prompt_embeds` instead. Ignored when not using guidance (i.e., ignored if `guidance_scale` is
+                less than `1`).
+            do_classifier_free_guidance (`bool`, *optional*, defaults to `True`):
+                Whether to use classifier free guidance or not.
+            num_videos_per_prompt (`int`, *optional*, defaults to 1):
+                Number of videos that should be generated per prompt. torch device to place the resulting embeddings on
+            prompt_embeds (`torch.Tensor`, *optional*):
+                Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not
+                provided, text embeddings will be generated from `prompt` input argument.
+            negative_prompt_embeds (`torch.Tensor`, *optional*):
+                Pre-generated negative text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt
+                weighting. If not provided, negative_prompt_embeds will be generated from `negative_prompt` input
+                argument.
+            device: (`torch.device`, *optional*):
+                torch device
+            dtype: (`torch.dtype`, *optional*):
+                torch dtype
+        """
+        device = device or self._execution_device
+
+        prompt = [prompt] if isinstance(prompt, str) else prompt
+        if prompt is not None:
+            batch_size = len(prompt)
+        else:
+            batch_size = prompt_embeds.shape[0]
+
+        if prompt_embeds is None:
+            prompt_embeds, prompt_attention_mask = self._get_t5_prompt_embeds(
+                prompt=prompt,
+                num_videos_per_prompt=num_videos_per_prompt,
+                max_sequence_length=max_sequence_length,
+                device=device,
+                dtype=dtype,
+            )
+
+        if do_classifier_free_guidance and negative_prompt_embeds is None:
+            negative_prompt = negative_prompt or ""
+            negative_prompt = batch_size * [negative_prompt] if isinstance(negative_prompt, str) else negative_prompt
+
+            if prompt is not None and type(prompt) is not type(negative_prompt):
+                raise TypeError(
+                    f"`negative_prompt` should be the same type to `prompt`, but got {type(negative_prompt)} !="
+                    f" {type(prompt)}."
+                )
+            elif batch_size != len(negative_prompt):
+                raise ValueError(
+                    f"`negative_prompt`: {negative_prompt} has batch size {len(negative_prompt)}, but `prompt`:"
+                    f" {prompt} has batch size {batch_size}. Please make sure that passed `negative_prompt` matches"
+                    " the batch size of `prompt`."
+                )
+
+            negative_prompt_embeds, negative_prompt_attention_mask = self._get_t5_prompt_embeds(
+                prompt=negative_prompt,
+                num_videos_per_prompt=num_videos_per_prompt,
+                max_sequence_length=max_sequence_length,
+                device=device,
+                dtype=dtype,
+            )
+
+        return prompt_embeds, prompt_attention_mask, negative_prompt_embeds, negative_prompt_attention_mask
+
+    def check_inputs(
+        self,
+        prompt,
+        conditions,
+        image,
+        video,
+        frame_index,
+        strength,
+        height,
+        width,
+        callback_on_step_end_tensor_inputs=None,
+        prompt_embeds=None,
+        negative_prompt_embeds=None,
+        prompt_attention_mask=None,
+        negative_prompt_attention_mask=None,
+    ):
+        if height % 32 != 0 or width % 32 != 0:
+            raise ValueError(f"`height` and `width` have to be divisible by 32 but are {height} and {width}.")
+
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
+        if prompt is not None and prompt_embeds is not None:
+            raise ValueError(
+                f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"
+                " only forward one of the two."
+            )
+        elif prompt is None and prompt_embeds is None:
+            raise ValueError(
+                "Provide either `prompt` or `prompt_embeds`. Cannot leave both `prompt` and `prompt_embeds` undefined."
+            )
+        elif prompt is not None and (not isinstance(prompt, str) and not isinstance(prompt, list)):
+            raise ValueError(f"`prompt` has to be of type `str` or `list` but is {type(prompt)}")
+
+        if prompt_embeds is not None and prompt_attention_mask is None:
+            raise ValueError("Must provide `prompt_attention_mask` when specifying `prompt_embeds`.")
+
+        if negative_prompt_embeds is not None and negative_prompt_attention_mask is None:
+            raise ValueError("Must provide `negative_prompt_attention_mask` when specifying `negative_prompt_embeds`.")
+
+        if prompt_embeds is not None and negative_prompt_embeds is not None:
+            if prompt_embeds.shape != negative_prompt_embeds.shape:
+                raise ValueError(
+                    "`prompt_embeds` and `negative_prompt_embeds` must have the same shape when passed directly, but"
+                    f" got: `prompt_embeds` {prompt_embeds.shape} != `negative_prompt_embeds`"
+                    f" {negative_prompt_embeds.shape}."
+                )
+            if prompt_attention_mask.shape != negative_prompt_attention_mask.shape:
+                raise ValueError(
+                    "`prompt_attention_mask` and `negative_prompt_attention_mask` must have the same shape when passed directly, but"
+                    f" got: `prompt_attention_mask` {prompt_attention_mask.shape} != `negative_prompt_attention_mask`"
+                    f" {negative_prompt_attention_mask.shape}."
+                )
+
+        if conditions is not None and (image is not None or video is not None):
+            raise ValueError("If `conditions` is provided, `image` and `video` must not be provided.")
+
+        if conditions is None and (image is None and video is None):
+            raise ValueError("If `conditions` is not provided, `image` or `video` must be provided.")
+
+        if conditions is None:
+            if isinstance(image, list) and isinstance(frame_index, list) and len(image) != len(frame_index):
+                raise ValueError(
+                    "If `conditions` is not provided, `image` and `frame_index` must be of the same length."
+                )
+            elif isinstance(image, list) and isinstance(strength, list) and len(image) != len(strength):
+                raise ValueError("If `conditions` is not provided, `image` and `strength` must be of the same length.")
+            elif isinstance(video, list) and isinstance(frame_index, list) and len(video) != len(frame_index):
+                raise ValueError(
+                    "If `conditions` is not provided, `video` and `frame_index` must be of the same length."
+                )
+            elif isinstance(video, list) and isinstance(strength, list) and len(video) != len(strength):
+                raise ValueError("If `conditions` is not provided, `video` and `strength` must be of the same length.")
+
+    @staticmethod
+    def _prepare_video_ids(
+        batch_size: int,
+        num_frames: int,
+        height: int,
+        width: int,
+        patch_size: int = 1,
+        patch_size_t: int = 1,
+        device: torch.device = None,
+    ) -> torch.Tensor:
+        latent_sample_coords = torch.meshgrid(
+            torch.arange(0, num_frames, patch_size_t, device=device),
+            torch.arange(0, height, patch_size, device=device),
+            torch.arange(0, width, patch_size, device=device),
+            indexing="ij",
+        )
+        latent_sample_coords = torch.stack(latent_sample_coords, dim=0)
+        latent_coords = latent_sample_coords.unsqueeze(0).repeat(batch_size, 1, 1, 1, 1)
+        latent_coords = latent_coords.reshape(batch_size, -1, num_frames * height * width)
+
+        return latent_coords
+
+    @staticmethod
+    def _scale_video_ids(
+        video_ids: torch.Tensor,
+        scale_factor: int = 32,
+        scale_factor_t: int = 8,
+        frame_index: int = 0,
+        device: torch.device = None,
+    ) -> torch.Tensor:
+        scaled_latent_coords = (
+            video_ids
+            * torch.tensor([scale_factor_t, scale_factor, scale_factor], device=video_ids.device)[None, :, None]
+        )
+        scaled_latent_coords[:, 0] = (scaled_latent_coords[:, 0] + 1 - scale_factor_t).clamp(min=0)
+        scaled_latent_coords[:, 0] += frame_index
+
+        return scaled_latent_coords
+
+    @staticmethod
+    # Copied from diffusers.pipelines.ltx.pipeline_ltx.LTXPipeline._pack_latents
+    def _pack_latents(latents: torch.Tensor, patch_size: int = 1, patch_size_t: int = 1) -> torch.Tensor:
+        # Unpacked latents of shape are [B, C, F, H, W] are patched into tokens of shape [B, C, F // p_t, p_t, H // p, p, W // p, p].
+        # The patch dimensions are then permuted and collapsed into the channel dimension of shape:
+        # [B, F // p_t * H // p * W // p, C * p_t * p * p] (an ndim=3 tensor).
+        # dim=0 is the batch size, dim=1 is the effective video sequence length, dim=2 is the effective number of input features
+        batch_size, num_channels, num_frames, height, width = latents.shape
+        post_patch_num_frames = num_frames // patch_size_t
+        post_patch_height = height // patch_size
+        post_patch_width = width // patch_size
+        latents = latents.reshape(
+            batch_size,
+            -1,
+            post_patch_num_frames,
+            patch_size_t,
+            post_patch_height,
+            patch_size,
+            post_patch_width,
+            patch_size,
+        )
+        latents = latents.permute(0, 2, 4, 6, 1, 3, 5, 7).flatten(4, 7).flatten(1, 3)
+        return latents
+
+    @staticmethod
+    # Copied from diffusers.pipelines.ltx.pipeline_ltx.LTXPipeline._unpack_latents
+    def _unpack_latents(
+        latents: torch.Tensor, num_frames: int, height: int, width: int, patch_size: int = 1, patch_size_t: int = 1
+    ) -> torch.Tensor:
+        # Packed latents of shape [B, S, D] (S is the effective video sequence length, D is the effective feature dimensions)
+        # are unpacked and reshaped into a video tensor of shape [B, C, F, H, W]. This is the inverse operation of
+        # what happens in the `_pack_latents` method.
+        batch_size = latents.size(0)
+        latents = latents.reshape(batch_size, num_frames, height, width, -1, patch_size_t, patch_size, patch_size)
+        latents = latents.permute(0, 4, 1, 5, 2, 6, 3, 7).flatten(6, 7).flatten(4, 5).flatten(2, 3)
+        return latents
+
+    @staticmethod
+    # Copied from diffusers.pipelines.ltx.pipeline_ltx.LTXPipeline._normalize_latents
+    def _normalize_latents(
+        latents: torch.Tensor, latents_mean: torch.Tensor, latents_std: torch.Tensor, scaling_factor: float = 1.0
+    ) -> torch.Tensor:
+        # Normalize latents across the channel dimension [B, C, F, H, W]
+        latents_mean = latents_mean.view(1, -1, 1, 1, 1).to(latents.device, latents.dtype)
+        latents_std = latents_std.view(1, -1, 1, 1, 1).to(latents.device, latents.dtype)
+        latents = (latents - latents_mean) * scaling_factor / latents_std
+        return latents
+
+    @staticmethod
+    # Copied from diffusers.pipelines.ltx.pipeline_ltx.LTXPipeline._denormalize_latents
+    def _denormalize_latents(
+        latents: torch.Tensor, latents_mean: torch.Tensor, latents_std: torch.Tensor, scaling_factor: float = 1.0
+    ) -> torch.Tensor:
+        # Denormalize latents across the channel dimension [B, C, F, H, W]
+        latents_mean = latents_mean.view(1, -1, 1, 1, 1).to(latents.device, latents.dtype)
+        latents_std = latents_std.view(1, -1, 1, 1, 1).to(latents.device, latents.dtype)
+        latents = latents * latents_std / scaling_factor + latents_mean
+        return latents
+
+    def trim_conditioning_sequence(self, start_frame: int, sequence_num_frames: int, target_num_frames: int):
+        """
+        Trim a conditioning sequence to the allowed number of frames.
+
+        Args:
+            start_frame (int): The target frame number of the first frame in the sequence.
+            sequence_num_frames (int): The number of frames in the sequence.
+            target_num_frames (int): The target number of frames in the generated video.
+        Returns:
+            int: updated sequence length
+        """
+        scale_factor = self.vae_temporal_compression_ratio
+        num_frames = min(sequence_num_frames, target_num_frames - start_frame)
+        # Trim down to a multiple of temporal_scale_factor frames plus 1
+        num_frames = (num_frames - 1) // scale_factor * scale_factor + 1
+        return num_frames
+
+    @staticmethod
+    def add_noise_to_image_conditioning_latents(
+        t: float,
+        init_latents: torch.Tensor,
+        latents: torch.Tensor,
+        noise_scale: float,
+        conditioning_mask: torch.Tensor,
+        generator,
+        eps=1e-6,
+    ):
+        """
+        Add timestep-dependent noise to the hard-conditioning latents. This helps with motion continuity, especially
+        when conditioned on a single frame.
+        """
+        noise = randn_tensor(
+            latents.shape,
+            generator=generator,
+            device=latents.device,
+            dtype=latents.dtype,
+        )
+        # Add noise only to hard-conditioning latents (conditioning_mask = 1.0)
+        need_to_noise = (conditioning_mask > 1.0 - eps).unsqueeze(-1)
+        noised_latents = init_latents + noise_scale * noise * (t**2)
+        latents = torch.where(need_to_noise, noised_latents, latents)
+        return latents
+
+    def prepare_latents(
+        self,
+        conditions: List[torch.Tensor],
+        condition_strength: List[float],
+        condition_frame_index: List[int],
+        batch_size: int = 1,
+        num_channels_latents: int = 128,
+        height: int = 512,
+        width: int = 704,
+        num_frames: int = 161,
+        num_prefix_latent_frames: int = 2,
+        generator: Optional[torch.Generator] = None,
+        device: Optional[torch.device] = None,
+        dtype: Optional[torch.dtype] = None,
+    ) -> None:
+        num_latent_frames = (num_frames - 1) // self.vae_temporal_compression_ratio + 1
+        latent_height = height // self.vae_spatial_compression_ratio
+        latent_width = width // self.vae_spatial_compression_ratio
+
+        shape = (batch_size, num_channels_latents, num_latent_frames, latent_height, latent_width)
+        latents = randn_tensor(shape, generator=generator, device=device, dtype=dtype)
+
+        condition_latent_frames_mask = torch.zeros((batch_size, num_latent_frames), device=device, dtype=torch.float32)
+
+        extra_conditioning_latents = []
+        extra_conditioning_video_ids = []
+        extra_conditioning_mask = []
+        extra_conditioning_num_latents = 0
+        for data, strength, frame_index in zip(conditions, condition_strength, condition_frame_index):
+            condition_latents = retrieve_latents(self.vae.encode(data), generator=generator)
+            condition_latents = self._normalize_latents(
+                condition_latents, self.vae.latents_mean, self.vae.latents_std
+            ).to(device, dtype=dtype)
+
+            num_data_frames = data.size(2)
+            num_cond_frames = condition_latents.size(2)
+
+            if frame_index == 0:
+                latents[:, :, :num_cond_frames] = torch.lerp(
+                    latents[:, :, :num_cond_frames], condition_latents, strength
+                )
+                condition_latent_frames_mask[:, :num_cond_frames] = strength
+
+            else:
+                if num_data_frames > 1:
+                    if num_cond_frames < num_prefix_latent_frames:
+                        raise ValueError(
+                            f"Number of latent frames must be at least {num_prefix_latent_frames} but got {num_data_frames}."
+                        )
+
+                    if num_cond_frames > num_prefix_latent_frames:
+                        start_frame = frame_index // self.vae_temporal_compression_ratio + num_prefix_latent_frames
+                        end_frame = start_frame + num_cond_frames - num_prefix_latent_frames
+                        latents[:, :, start_frame:end_frame] = torch.lerp(
+                            latents[:, :, start_frame:end_frame],
+                            condition_latents[:, :, num_prefix_latent_frames:],
+                            strength,
+                        )
+                        condition_latent_frames_mask[:, start_frame:end_frame] = strength
+                        condition_latents = condition_latents[:, :, :num_prefix_latent_frames]
+
+                noise = randn_tensor(condition_latents.shape, generator=generator, device=device, dtype=dtype)
+                condition_latents = torch.lerp(noise, condition_latents, strength)
+
+                condition_video_ids = self._prepare_video_ids(
+                    batch_size,
+                    condition_latents.size(2),
+                    latent_height,
+                    latent_width,
+                    patch_size=self.transformer_spatial_patch_size,
+                    patch_size_t=self.transformer_temporal_patch_size,
+                    device=device,
+                )
+                condition_video_ids = self._scale_video_ids(
+                    condition_video_ids,
+                    scale_factor=self.vae_spatial_compression_ratio,
+                    scale_factor_t=self.vae_temporal_compression_ratio,
+                    frame_index=frame_index,
+                    device=device,
+                )
+                condition_latents = self._pack_latents(
+                    condition_latents,
+                    self.transformer_spatial_patch_size,
+                    self.transformer_temporal_patch_size,
+                )
+                condition_conditioning_mask = torch.full(
+                    condition_latents.shape[:2], strength, device=device, dtype=dtype
+                )
+
+                extra_conditioning_latents.append(condition_latents)
+                extra_conditioning_video_ids.append(condition_video_ids)
+                extra_conditioning_mask.append(condition_conditioning_mask)
+                extra_conditioning_num_latents += condition_latents.size(1)
+
+        video_ids = self._prepare_video_ids(
+            batch_size,
+            num_latent_frames,
+            latent_height,
+            latent_width,
+            patch_size_t=self.transformer_temporal_patch_size,
+            patch_size=self.transformer_spatial_patch_size,
+            device=device,
+        )
+        conditioning_mask = condition_latent_frames_mask.gather(1, video_ids[:, 0])
+        video_ids = self._scale_video_ids(
+            video_ids,
+            scale_factor=self.vae_spatial_compression_ratio,
+            scale_factor_t=self.vae_temporal_compression_ratio,
+            frame_index=0,
+            device=device,
+        )
+        latents = self._pack_latents(
+            latents, self.transformer_spatial_patch_size, self.transformer_temporal_patch_size
+        )
+
+        if len(extra_conditioning_latents) > 0:
+            latents = torch.cat([*extra_conditioning_latents, latents], dim=1)
+            video_ids = torch.cat([*extra_conditioning_video_ids, video_ids], dim=2)
+            conditioning_mask = torch.cat([*extra_conditioning_mask, conditioning_mask], dim=1)
+
+        return latents, conditioning_mask, video_ids, extra_conditioning_num_latents
+
+    @property
+    def guidance_scale(self):
+        return self._guidance_scale
+
+    @property
+    def do_classifier_free_guidance(self):
+        return self._guidance_scale > 1.0
+
+    @property
+    def num_timesteps(self):
+        return self._num_timesteps
+
+    @property
+    def attention_kwargs(self):
+        return self._attention_kwargs
+
+    @property
+    def interrupt(self):
+        return self._interrupt
+
+    @torch.no_grad()
+    @replace_example_docstring(EXAMPLE_DOC_STRING)
+    def __call__(
+        self,
+        conditions: Union[LTXVideoCondition, List[LTXVideoCondition]] = None,
+        image: Union[PipelineImageInput, List[PipelineImageInput]] = None,
+        video: List[PipelineImageInput] = None,
+        frame_index: Union[int, List[int]] = 0,
+        strength: Union[float, List[float]] = 1.0,
+        prompt: Union[str, List[str]] = None,
+        negative_prompt: Optional[Union[str, List[str]]] = None,
+        height: int = 512,
+        width: int = 704,
+        num_frames: int = 161,
+        frame_rate: int = 25,
+        num_inference_steps: int = 50,
+        timesteps: List[int] = None,
+        guidance_scale: float = 3,
+        image_cond_noise_scale: float = 0.15,
+        num_videos_per_prompt: Optional[int] = 1,
+        generator: Optional[Union[torch.Generator, List[torch.Generator]]] = None,
+        latents: Optional[torch.Tensor] = None,
+        prompt_embeds: Optional[torch.Tensor] = None,
+        prompt_attention_mask: Optional[torch.Tensor] = None,
+        negative_prompt_embeds: Optional[torch.Tensor] = None,
+        negative_prompt_attention_mask: Optional[torch.Tensor] = None,
+        decode_timestep: Union[float, List[float]] = 0.0,
+        decode_noise_scale: Optional[Union[float, List[float]]] = None,
+        output_type: Optional[str] = "pil",
+        return_dict: bool = True,
+        attention_kwargs: Optional[Dict[str, Any]] = None,
+        callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
+        callback_on_step_end_tensor_inputs: List[str] = ["latents"],
+        max_sequence_length: int = 256,
+    ):
+        r"""
+        Function invoked when calling the pipeline for generation.
+
+        Args:
+            conditions (`List[LTXVideoCondition], *optional*`):
+                The list of frame-conditioning items for the video generation.If not provided, conditions will be
+                created using `image`, `video`, `frame_index` and `strength`.
+            image (`PipelineImageInput` or `List[PipelineImageInput]`, *optional*):
+                The image or images to condition the video generation. If not provided, one has to pass `video` or
+                `conditions`.
+            video (`List[PipelineImageInput]`, *optional*):
+                The video to condition the video generation. If not provided, one has to pass `image` or `conditions`.
+            frame_index (`int` or `List[int]`, *optional*):
+                The frame index or frame indices at which the image or video will conditionally effect the video
+                generation. If not provided, one has to pass `conditions`.
+            strength (`float` or `List[float]`, *optional*):
+                The strength or strengths of the conditioning effect. If not provided, one has to pass `conditions`.
+            prompt (`str` or `List[str]`, *optional*):
+                The prompt or prompts to guide the image generation. If not defined, one has to pass `prompt_embeds`.
+                instead.
+            height (`int`, defaults to `512`):
+                The height in pixels of the generated image. This is set to 480 by default for the best results.
+            width (`int`, defaults to `704`):
+                The width in pixels of the generated image. This is set to 848 by default for the best results.
+            num_frames (`int`, defaults to `161`):
+                The number of video frames to generate
+            num_inference_steps (`int`, *optional*, defaults to 50):
+                The number of denoising steps. More denoising steps usually lead to a higher quality image at the
+                expense of slower inference.
+            timesteps (`List[int]`, *optional*):
+                Custom timesteps to use for the denoising process with schedulers which support a `timesteps` argument
+                in their `set_timesteps` method. If not defined, the default behavior when `num_inference_steps` is
+                passed will be used. Must be in descending order.
+            guidance_scale (`float`, defaults to `3 `):
+                Guidance scale as defined in [Classifier-Free Diffusion Guidance](https://arxiv.org/abs/2207.12598).
+                `guidance_scale` is defined as `w` of equation 2. of [Imagen
+                Paper](https://arxiv.org/pdf/2205.11487.pdf). Guidance scale is enabled by setting `guidance_scale >
+                1`. Higher guidance scale encourages to generate images that are closely linked to the text `prompt`,
+                usually at the expense of lower image quality.
+            num_videos_per_prompt (`int`, *optional*, defaults to 1):
+                The number of videos to generate per prompt.
+            generator (`torch.Generator` or `List[torch.Generator]`, *optional*):
+                One or a list of [torch generator(s)](https://pytorch.org/docs/stable/generated/torch.Generator.html)
+                to make generation deterministic.
+            latents (`torch.Tensor`, *optional*):
+                Pre-generated noisy latents, sampled from a Gaussian distribution, to be used as inputs for image
+                generation. Can be used to tweak the same generation with different prompts. If not provided, a latents
+                tensor will ge generated by sampling using the supplied random `generator`.
+            prompt_embeds (`torch.Tensor`, *optional*):
+                Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not
+                provided, text embeddings will be generated from `prompt` input argument.
+            prompt_attention_mask (`torch.Tensor`, *optional*):
+                Pre-generated attention mask for text embeddings.
+            negative_prompt_embeds (`torch.FloatTensor`, *optional*):
+                Pre-generated negative text embeddings. For PixArt-Sigma this negative prompt should be "". If not
+                provided, negative_prompt_embeds will be generated from `negative_prompt` input argument.
+            negative_prompt_attention_mask (`torch.FloatTensor`, *optional*):
+                Pre-generated attention mask for negative text embeddings.
+            decode_timestep (`float`, defaults to `0.0`):
+                The timestep at which generated video is decoded.
+            decode_noise_scale (`float`, defaults to `None`):
+                The interpolation factor between random noise and denoised latents at the decode timestep.
+            output_type (`str`, *optional*, defaults to `"pil"`):
+                The output format of the generate image. Choose between
+                [PIL](https://pillow.readthedocs.io/en/stable/): `PIL.Image.Image` or `np.array`.
+            return_dict (`bool`, *optional*, defaults to `True`):
+                Whether or not to return a [`~pipelines.ltx.LTXPipelineOutput`] instead of a plain tuple.
+            attention_kwargs (`dict`, *optional*):
+                A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under
+                `self.processor` in
+                [diffusers.models.attention_processor](https://github.com/huggingface/diffusers/blob/main/src/diffusers/models/attention_processor.py).
+            callback_on_step_end (`Callable`, *optional*):
+                A function that calls at the end of each denoising steps during the inference. The function is called
+                with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int,
+                callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by
+                `callback_on_step_end_tensor_inputs`.
+            callback_on_step_end_tensor_inputs (`List`, *optional*):
+                The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list
+                will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the
+                `._callback_tensor_inputs` attribute of your pipeline class.
+            max_sequence_length (`int` defaults to `128 `):
+                Maximum sequence length to use with the `prompt`.
+
+        Examples:
+
+        Returns:
+            [`~pipelines.ltx.LTXPipelineOutput`] or `tuple`:
+                If `return_dict` is `True`, [`~pipelines.ltx.LTXPipelineOutput`] is returned, otherwise a `tuple` is
+                returned where the first element is a list with the generated images.
+        """
+
+        if isinstance(callback_on_step_end, (PipelineCallback, MultiPipelineCallbacks)):
+            callback_on_step_end_tensor_inputs = callback_on_step_end.tensor_inputs
+        if latents is not None:
+            raise ValueError("Passing latents is not yet supported.")
+
+        # 1. Check inputs. Raise error if not correct
+        self.check_inputs(
+            prompt=prompt,
+            conditions=conditions,
+            image=image,
+            video=video,
+            frame_index=frame_index,
+            strength=strength,
+            height=height,
+            width=width,
+            callback_on_step_end_tensor_inputs=callback_on_step_end_tensor_inputs,
+            prompt_embeds=prompt_embeds,
+            negative_prompt_embeds=negative_prompt_embeds,
+            prompt_attention_mask=prompt_attention_mask,
+            negative_prompt_attention_mask=negative_prompt_attention_mask,
+        )
+
+        self._guidance_scale = guidance_scale
+        self._attention_kwargs = attention_kwargs
+        self._interrupt = False
+
+        # 2. Define call parameters
+        if prompt is not None and isinstance(prompt, str):
+            batch_size = 1
+        elif prompt is not None and isinstance(prompt, list):
+            batch_size = len(prompt)
+        else:
+            batch_size = prompt_embeds.shape[0]
+
+        if conditions is not None:
+            if not isinstance(conditions, list):
+                conditions = [conditions]
+
+            strength = [condition.strength for condition in conditions]
+            frame_index = [condition.frame_index for condition in conditions]
+            image = [condition.image for condition in conditions]
+            video = [condition.video for condition in conditions]
+        else:
+            if not isinstance(image, list):
+                image = [image]
+                num_conditions = 1
+            elif isinstance(image, list):
+                num_conditions = len(image)
+            if not isinstance(video, list):
+                video = [video]
+                num_conditions = 1
+            elif isinstance(video, list):
+                num_conditions = len(video)
+
+            if not isinstance(frame_index, list):
+                frame_index = [frame_index] * num_conditions
+            if not isinstance(strength, list):
+                strength = [strength] * num_conditions
+
+        device = self._execution_device
+
+        # 3. Prepare text embeddings
+        (
+            prompt_embeds,
+            prompt_attention_mask,
+            negative_prompt_embeds,
+            negative_prompt_attention_mask,
+        ) = self.encode_prompt(
+            prompt=prompt,
+            negative_prompt=negative_prompt,
+            do_classifier_free_guidance=self.do_classifier_free_guidance,
+            num_videos_per_prompt=num_videos_per_prompt,
+            prompt_embeds=prompt_embeds,
+            negative_prompt_embeds=negative_prompt_embeds,
+            prompt_attention_mask=prompt_attention_mask,
+            negative_prompt_attention_mask=negative_prompt_attention_mask,
+            max_sequence_length=max_sequence_length,
+            device=device,
+        )
+        if self.do_classifier_free_guidance:
+            prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds], dim=0)
+            prompt_attention_mask = torch.cat([negative_prompt_attention_mask, prompt_attention_mask], dim=0)
+
+        vae_dtype = self.vae.dtype
+
+        conditioning_tensors = []
+        for condition_image, condition_video, condition_frame_index, condition_strength in zip(
+            image, video, frame_index, strength
+        ):
+            if condition_image is not None:
+                condition_tensor = (
+                    self.video_processor.preprocess(condition_image, height, width)
+                    .unsqueeze(2)
+                    .to(device, dtype=vae_dtype)
+                )
+            elif condition_video is not None:
+                condition_tensor = self.video_processor.preprocess_video(condition_video, height, width)
+                num_frames_input = condition_tensor.size(2)
+                num_frames_output = self.trim_conditioning_sequence(
+                    condition_frame_index, num_frames_input, num_frames
+                )
+                condition_tensor = condition_tensor[:, :, :num_frames_output]
+                condition_tensor = condition_tensor.to(device, dtype=vae_dtype)
+            else:
+                raise ValueError("Either `image` or `video` must be provided in the `LTXVideoCondition`.")
+
+            if condition_tensor.size(2) % self.vae_temporal_compression_ratio != 1:
+                raise ValueError(
+                    f"Number of frames in the video must be of the form (k * {self.vae_temporal_compression_ratio} + 1) "
+                    f"but got {condition_tensor.size(2)} frames."
+                )
+            conditioning_tensors.append(condition_tensor)
+
+        # 4. Prepare latent variables
+        num_channels_latents = self.transformer.config.in_channels
+        latents, conditioning_mask, video_coords, extra_conditioning_num_latents = self.prepare_latents(
+            conditioning_tensors,
+            strength,
+            frame_index,
+            batch_size=batch_size * num_videos_per_prompt,
+            num_channels_latents=num_channels_latents,
+            height=height,
+            width=width,
+            num_frames=num_frames,
+            generator=generator,
+            device=device,
+            dtype=torch.float32,
+        )
+
+        video_coords = video_coords.float()
+        video_coords[:, 0] = video_coords[:, 0] * (1.0 / frame_rate)
+
+        init_latents = latents.clone()
+
+        if self.do_classifier_free_guidance:
+            video_coords = torch.cat([video_coords, video_coords], dim=0)
+
+        # 5. Prepare timesteps
+        latent_num_frames = (num_frames - 1) // self.vae_temporal_compression_ratio + 1
+        latent_height = height // self.vae_spatial_compression_ratio
+        latent_width = width // self.vae_spatial_compression_ratio
+        sigmas = linear_quadratic_schedule(num_inference_steps)
+        timesteps = sigmas * 1000
+        timesteps, num_inference_steps = retrieve_timesteps(
+            self.scheduler,
+            num_inference_steps,
+            device,
+            timesteps=timesteps,
+        )
+        num_warmup_steps = max(len(timesteps) - num_inference_steps * self.scheduler.order, 0)
+        self._num_timesteps = len(timesteps)
+
+        # 7. Denoising loop
+        with self.progress_bar(total=num_inference_steps) as progress_bar:
+            for i, t in enumerate(timesteps):
+                if self.interrupt:
+                    continue
+
+                if image_cond_noise_scale > 0:
+                    # Add timestep-dependent noise to the hard-conditioning latents
+                    # This helps with motion continuity, especially when conditioned on a single frame
+                    latents = self.add_noise_to_image_conditioning_latents(
+                        t / 1000.0,
+                        init_latents,
+                        latents,
+                        image_cond_noise_scale,
+                        conditioning_mask,
+                        generator,
+                    )
+
+                latent_model_input = torch.cat([latents] * 2) if self.do_classifier_free_guidance else latents
+                conditioning_mask_model_input = (
+                    torch.cat([conditioning_mask, conditioning_mask])
+                    if self.do_classifier_free_guidance
+                    else conditioning_mask
+                )
+                latent_model_input = latent_model_input.to(prompt_embeds.dtype)
+
+                # broadcast to batch dimension in a way that's compatible with ONNX/Core ML
+                timestep = t.expand(latent_model_input.shape[0]).unsqueeze(-1).float()
+                timestep = torch.min(timestep, (1 - conditioning_mask_model_input) * 1000.0)
+
+                noise_pred = self.transformer(
+                    hidden_states=latent_model_input,
+                    encoder_hidden_states=prompt_embeds,
+                    timestep=timestep,
+                    encoder_attention_mask=prompt_attention_mask,
+                    video_coords=video_coords,
+                    attention_kwargs=attention_kwargs,
+                    return_dict=False,
+                )[0]
+
+                if self.do_classifier_free_guidance:
+                    noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
+                    noise_pred = noise_pred_uncond + self.guidance_scale * (noise_pred_text - noise_pred_uncond)
+                    timestep, _ = timestep.chunk(2)
+
+                denoised_latents = self.scheduler.step(
+                    -noise_pred, t, latents, per_token_timesteps=timestep, return_dict=False
+                )[0]
+                tokens_to_denoise_mask = (t / 1000 - 1e-6 < (1.0 - conditioning_mask)).unsqueeze(-1)
+                latents = torch.where(tokens_to_denoise_mask, denoised_latents, latents)
+
+                if callback_on_step_end is not None:
+                    callback_kwargs = {}
+                    for k in callback_on_step_end_tensor_inputs:
+                        callback_kwargs[k] = locals()[k]
+                    callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
+
+                    latents = callback_outputs.pop("latents", latents)
+                    prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
+
+                # call the callback, if provided
+                if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0):
+                    progress_bar.update()
+
+                if XLA_AVAILABLE:
+                    xm.mark_step()
+
+        latents = latents[:, extra_conditioning_num_latents:]
+        latents = self._unpack_latents(
+            latents,
+            latent_num_frames,
+            latent_height,
+            latent_width,
+            self.transformer_spatial_patch_size,
+            self.transformer_temporal_patch_size,
+        )
+
+        if output_type == "latent":
+            video = latents
+        else:
+            latents = self._denormalize_latents(
+                latents, self.vae.latents_mean, self.vae.latents_std, self.vae.config.scaling_factor
+            )
+            latents = latents.to(prompt_embeds.dtype)
+
+            if not self.vae.config.timestep_conditioning:
+                timestep = None
+            else:
+                noise = torch.randn(latents.shape, generator=generator, device=device, dtype=latents.dtype)
+                if not isinstance(decode_timestep, list):
+                    decode_timestep = [decode_timestep] * batch_size
+                if decode_noise_scale is None:
+                    decode_noise_scale = decode_timestep
+                elif not isinstance(decode_noise_scale, list):
+                    decode_noise_scale = [decode_noise_scale] * batch_size
+
+                timestep = torch.tensor(decode_timestep, device=device, dtype=latents.dtype)
+                decode_noise_scale = torch.tensor(decode_noise_scale, device=device, dtype=latents.dtype)[
+                    :, None, None, None, None
+                ]
+                latents = (1 - decode_noise_scale) * latents + decode_noise_scale * noise
+
+            video = self.vae.decode(latents, timestep, return_dict=False)[0]
+            video = self.video_processor.postprocess_video(video, output_type=output_type)
+
+        # Offload all models
+        self.maybe_free_model_hooks()
+
+        if not return_dict:
+            return (video,)
+
+        return LTXPipelineOutput(frames=video)

src/diffusers/pipelines/ltx/pipeline_ltx_image2video.py

@@ -764,9 +764,8 @@ class LTXImageToVideoPipeline(DiffusionPipeline, FromSingleFileMixin, LTXVideoLo
         self._num_timesteps = len(timesteps)
 
         # 6. Prepare micro-conditions
-        latent_frame_rate = frame_rate / self.vae_temporal_compression_ratio
         rope_interpolation_scale = (
-            1 / latent_frame_rate,
+            self.vae_temporal_compression_ratio / frame_rate,
             self.vae_spatial_compression_ratio,
             self.vae_spatial_compression_ratio,
         )

src/diffusers/schedulers/scheduling_flow_match_euler_discrete.py

@@ -377,6 +377,7 @@ class FlowMatchEulerDiscreteScheduler(SchedulerMixin, ConfigMixin):
         s_tmax: float = float("inf"),
         s_noise: float = 1.0,
         generator: Optional[torch.Generator] = None,
+        per_token_timesteps: Optional[torch.Tensor] = None,
         return_dict: bool = True,
     ) -> Union[FlowMatchEulerDiscreteSchedulerOutput, Tuple]:
         """
@@ -397,6 +398,8 @@ class FlowMatchEulerDiscreteScheduler(SchedulerMixin, ConfigMixin):
                 Scaling factor for noise added to the sample.
             generator (`torch.Generator`, *optional*):
                 A random number generator.
+            per_token_timesteps (`torch.Tensor`, *optional*):
+                The timesteps for each token in the sample.
             return_dict (`bool`):
                 Whether or not to return a
                 [`~schedulers.scheduling_flow_match_euler_discrete.FlowMatchEulerDiscreteSchedulerOutput`] or tuple.
@@ -427,16 +430,26 @@ class FlowMatchEulerDiscreteScheduler(SchedulerMixin, ConfigMixin):
         # Upcast to avoid precision issues when computing prev_sample
         sample = sample.to(torch.float32)
 
-        sigma = self.sigmas[self.step_index]
-        sigma_next = self.sigmas[self.step_index + 1]
+        if per_token_timesteps is not None:
+            per_token_sigmas = per_token_timesteps / self.config.num_train_timesteps
 
-        prev_sample = sample + (sigma_next - sigma) * model_output
+            sigmas = self.sigmas[:, None, None]
+            lower_mask = sigmas < per_token_sigmas[None] - 1e-6
+            lower_sigmas = lower_mask * sigmas
+            lower_sigmas, _ = lower_sigmas.max(dim=0)
+            dt = (per_token_sigmas - lower_sigmas)[..., None]
+        else:
+            sigma = self.sigmas[self.step_index]
+            sigma_next = self.sigmas[self.step_index + 1]
+            dt = sigma_next - sigma
 
-        # Cast sample back to model compatible dtype
-        prev_sample = prev_sample.to(model_output.dtype)
+        prev_sample = sample + dt * model_output
 
         # upon completion increase step index by one
         self._step_index += 1
+        if per_token_timesteps is None:
+            # Cast sample back to model compatible dtype
+            prev_sample = prev_sample.to(model_output.dtype)
 
         if not return_dict:
             return (prev_sample,)

src/diffusers/utils/dummy_torch_and_transformers_objects.py

@@ -1217,6 +1217,21 @@ class LEditsPPPipelineStableDiffusionXL(metaclass=DummyObject):
         requires_backends(cls, ["torch", "transformers"])
 
 
+class LTXConditionPipeline(metaclass=DummyObject):
+    _backends = ["torch", "transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch", "transformers"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+
 class LTXImageToVideoPipeline(metaclass=DummyObject):
     _backends = ["torch", "transformers"]
 

tests/pipelines/ltx/test_ltx_condition.py

+# Copyright 2024 The HuggingFace Team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import inspect
+import unittest
+
+import numpy as np
+import torch
+from transformers import AutoTokenizer, T5EncoderModel
+
+from diffusers import (
+    AutoencoderKLLTXVideo,
+    FlowMatchEulerDiscreteScheduler,
+    LTXConditionPipeline,
+    LTXVideoTransformer3DModel,
+)
+from diffusers.pipelines.ltx.pipeline_ltx_condition import LTXVideoCondition
+from diffusers.utils.testing_utils import enable_full_determinism, torch_device
+
+from ..pipeline_params import TEXT_TO_IMAGE_BATCH_PARAMS, TEXT_TO_IMAGE_IMAGE_PARAMS, TEXT_TO_IMAGE_PARAMS
+from ..test_pipelines_common import PipelineTesterMixin, to_np
+
+
+enable_full_determinism()
+
+
+class LTXConditionPipelineFastTests(PipelineTesterMixin, unittest.TestCase):
+    pipeline_class = LTXConditionPipeline
+    params = TEXT_TO_IMAGE_PARAMS - {"cross_attention_kwargs"}
+    batch_params = TEXT_TO_IMAGE_BATCH_PARAMS.union({"image"})
+    image_params = TEXT_TO_IMAGE_IMAGE_PARAMS
+    image_latents_params = TEXT_TO_IMAGE_IMAGE_PARAMS
+    required_optional_params = frozenset(
+        [
+            "num_inference_steps",
+            "generator",
+            "latents",
+            "return_dict",
+            "callback_on_step_end",
+            "callback_on_step_end_tensor_inputs",
+        ]
+    )
+    test_xformers_attention = False
+
+    def get_dummy_components(self):
+        torch.manual_seed(0)
+        transformer = LTXVideoTransformer3DModel(
+            in_channels=8,
+            out_channels=8,
+            patch_size=1,
+            patch_size_t=1,
+            num_attention_heads=4,
+            attention_head_dim=8,
+            cross_attention_dim=32,
+            num_layers=1,
+            caption_channels=32,
+        )
+
+        torch.manual_seed(0)
+        vae = AutoencoderKLLTXVideo(
+            in_channels=3,
+            out_channels=3,
+            latent_channels=8,
+            block_out_channels=(8, 8, 8, 8),
+            decoder_block_out_channels=(8, 8, 8, 8),
+            layers_per_block=(1, 1, 1, 1, 1),
+            decoder_layers_per_block=(1, 1, 1, 1, 1),
+            spatio_temporal_scaling=(True, True, False, False),
+            decoder_spatio_temporal_scaling=(True, True, False, False),
+            decoder_inject_noise=(False, False, False, False, False),
+            upsample_residual=(False, False, False, False),
+            upsample_factor=(1, 1, 1, 1),
+            timestep_conditioning=False,
+            patch_size=1,
+            patch_size_t=1,
+            encoder_causal=True,
+            decoder_causal=False,
+        )
+        vae.use_framewise_encoding = False
+        vae.use_framewise_decoding = False
+
+        torch.manual_seed(0)
+        scheduler = FlowMatchEulerDiscreteScheduler()
+        text_encoder = T5EncoderModel.from_pretrained("hf-internal-testing/tiny-random-t5")
+        tokenizer = AutoTokenizer.from_pretrained("hf-internal-testing/tiny-random-t5")
+
+        components = {
+            "transformer": transformer,
+            "vae": vae,
+            "scheduler": scheduler,
+            "text_encoder": text_encoder,
+            "tokenizer": tokenizer,
+        }
+        return components
+
+    def get_dummy_inputs(self, device, seed=0, use_conditions=False):
+        if str(device).startswith("mps"):
+            generator = torch.manual_seed(seed)
+        else:
+            generator = torch.Generator(device=device).manual_seed(seed)
+
+        image = torch.randn((1, 3, 32, 32), generator=generator, device=device)
+        if use_conditions:
+            conditions = LTXVideoCondition(
+                image=image,
+            )
+        else:
+            conditions = None
+
+        inputs = {
+            "conditions": conditions,
+            "image": None if use_conditions else image,
+            "prompt": "dance monkey",
+            "negative_prompt": "",
+            "generator": generator,
+            "num_inference_steps": 2,
+            "guidance_scale": 3.0,
+            "height": 32,
+            "width": 32,
+            # 8 * k + 1 is the recommendation
+            "num_frames": 9,
+            "max_sequence_length": 16,
+            "output_type": "pt",
+        }
+
+        return inputs
+
+    def test_inference(self):
+        device = "cpu"
+
+        components = self.get_dummy_components()
+        pipe = self.pipeline_class(**components)
+        pipe.to(device)
+        pipe.set_progress_bar_config(disable=None)
+
+        inputs = self.get_dummy_inputs(device)
+        inputs2 = self.get_dummy_inputs(device, use_conditions=True)
+        video = pipe(**inputs).frames
+        generated_video = video[0]
+        video2 = pipe(**inputs2).frames
+        generated_video2 = video2[0]
+
+        self.assertEqual(generated_video.shape, (9, 3, 32, 32))
+
+        max_diff = np.abs(generated_video - generated_video2).max()
+        self.assertLessEqual(max_diff, 1e-3)
+
+    def test_callback_inputs(self):
+        sig = inspect.signature(self.pipeline_class.__call__)
+        has_callback_tensor_inputs = "callback_on_step_end_tensor_inputs" in sig.parameters
+        has_callback_step_end = "callback_on_step_end" in sig.parameters
+
+        if not (has_callback_tensor_inputs and has_callback_step_end):
+            return
+
+        components = self.get_dummy_components()
+        pipe = self.pipeline_class(**components)
+        pipe = pipe.to(torch_device)
+        pipe.set_progress_bar_config(disable=None)
+        self.assertTrue(
+            hasattr(pipe, "_callback_tensor_inputs"),
+            f" {self.pipeline_class} should have `_callback_tensor_inputs` that defines a list of tensor variables its callback function can use as inputs",
+        )
+
+        def callback_inputs_subset(pipe, i, t, callback_kwargs):
+            # iterate over callback args
+            for tensor_name, tensor_value in callback_kwargs.items():
+                # check that we're only passing in allowed tensor inputs
+                assert tensor_name in pipe._callback_tensor_inputs
+
+            return callback_kwargs
+
+        def callback_inputs_all(pipe, i, t, callback_kwargs):
+            for tensor_name in pipe._callback_tensor_inputs:
+                assert tensor_name in callback_kwargs
+
+            # iterate over callback args
+            for tensor_name, tensor_value in callback_kwargs.items():
+                # check that we're only passing in allowed tensor inputs
+                assert tensor_name in pipe._callback_tensor_inputs
+
+            return callback_kwargs
+
+        inputs = self.get_dummy_inputs(torch_device)
+
+        # Test passing in a subset
+        inputs["callback_on_step_end"] = callback_inputs_subset
+        inputs["callback_on_step_end_tensor_inputs"] = ["latents"]
+        output = pipe(**inputs)[0]
+
+        # Test passing in a everything
+        inputs["callback_on_step_end"] = callback_inputs_all
+        inputs["callback_on_step_end_tensor_inputs"] = pipe._callback_tensor_inputs
+        output = pipe(**inputs)[0]
+
+        def callback_inputs_change_tensor(pipe, i, t, callback_kwargs):
+            is_last = i == (pipe.num_timesteps - 1)
+            if is_last:
+                callback_kwargs["latents"] = torch.zeros_like(callback_kwargs["latents"])
+            return callback_kwargs
+
+        inputs["callback_on_step_end"] = callback_inputs_change_tensor
+        inputs["callback_on_step_end_tensor_inputs"] = pipe._callback_tensor_inputs
+        output = pipe(**inputs)[0]
+        assert output.abs().sum() < 1e10
+
+    def test_inference_batch_single_identical(self):
+        self._test_inference_batch_single_identical(batch_size=3, expected_max_diff=1e-3)
+
+    def test_attention_slicing_forward_pass(
+        self, test_max_difference=True, test_mean_pixel_difference=True, expected_max_diff=1e-3
+    ):
+        if not self.test_attention_slicing:
+            return
+
+        components = self.get_dummy_components()
+        pipe = self.pipeline_class(**components)
+        for component in pipe.components.values():
+            if hasattr(component, "set_default_attn_processor"):
+                component.set_default_attn_processor()
+        pipe.to(torch_device)
+        pipe.set_progress_bar_config(disable=None)
+
+        generator_device = "cpu"
+        inputs = self.get_dummy_inputs(generator_device)
+        output_without_slicing = pipe(**inputs)[0]
+
+        pipe.enable_attention_slicing(slice_size=1)
+        inputs = self.get_dummy_inputs(generator_device)
+        output_with_slicing1 = pipe(**inputs)[0]
+
+        pipe.enable_attention_slicing(slice_size=2)
+        inputs = self.get_dummy_inputs(generator_device)
+        output_with_slicing2 = pipe(**inputs)[0]
+
+        if test_max_difference:
+            max_diff1 = np.abs(to_np(output_with_slicing1) - to_np(output_without_slicing)).max()
+            max_diff2 = np.abs(to_np(output_with_slicing2) - to_np(output_without_slicing)).max()
+            self.assertLess(
+                max(max_diff1, max_diff2),
+                expected_max_diff,
+                "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",
+        )