File size: 8,315 Bytes
e8bdafd
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
from typing import Any, Dict, List, Tuple

import torch
from diffusers import (
    AutoencoderKLCogVideoX,
    CogVideoXDPMScheduler,
    CogVideoXPipeline,
    CogVideoXTransformer3DModel,
)
from diffusers.models.embeddings import get_3d_rotary_pos_embed
from PIL import Image
from transformers import AutoTokenizer, T5EncoderModel
from typing_extensions import override

from finetune.schemas import Components
from finetune.trainer import Trainer
from finetune.utils import unwrap_model

from ..utils import register


class CogVideoXT2VLoraTrainer(Trainer):
    UNLOAD_LIST = ["text_encoder", "vae"]

    @override
    def load_components(self) -> Components:
        components = Components()
        model_path = str(self.args.model_path)

        components.pipeline_cls = CogVideoXPipeline

        components.tokenizer = AutoTokenizer.from_pretrained(model_path, subfolder="tokenizer")

        components.text_encoder = T5EncoderModel.from_pretrained(model_path, subfolder="text_encoder")

        components.transformer = CogVideoXTransformer3DModel.from_pretrained(model_path, subfolder="transformer")

        components.vae = AutoencoderKLCogVideoX.from_pretrained(model_path, subfolder="vae")

        components.scheduler = CogVideoXDPMScheduler.from_pretrained(model_path, subfolder="scheduler")

        return components

    @override
    def initialize_pipeline(self) -> CogVideoXPipeline:
        pipe = CogVideoXPipeline(
            tokenizer=self.components.tokenizer,
            text_encoder=self.components.text_encoder,
            vae=self.components.vae,
            transformer=unwrap_model(self.accelerator, self.components.transformer),
            scheduler=self.components.scheduler,
        )
        return pipe

    @override
    def encode_video(self, video: torch.Tensor) -> torch.Tensor:
        # shape of input video: [B, C, F, H, W]
        vae = self.components.vae
        video = video.to(vae.device, dtype=vae.dtype)
        latent_dist = vae.encode(video).latent_dist
        latent = latent_dist.sample() * vae.config.scaling_factor
        return latent

    @override
    def encode_text(self, prompt: str) -> torch.Tensor:
        prompt_token_ids = self.components.tokenizer(
            prompt,
            padding="max_length",
            max_length=self.state.transformer_config.max_text_seq_length,
            truncation=True,
            add_special_tokens=True,
            return_tensors="pt",
        )
        prompt_token_ids = prompt_token_ids.input_ids
        prompt_embedding = self.components.text_encoder(prompt_token_ids.to(self.accelerator.device))[0]
        return prompt_embedding

    @override
    def collate_fn(self, samples: List[Dict[str, Any]]) -> Dict[str, Any]:
        ret = {"encoded_videos": [], "prompt_embedding": []}

        for sample in samples:
            encoded_video = sample["encoded_video"]
            prompt_embedding = sample["prompt_embedding"]

            ret["encoded_videos"].append(encoded_video)
            ret["prompt_embedding"].append(prompt_embedding)

        ret["encoded_videos"] = torch.stack(ret["encoded_videos"])
        ret["prompt_embedding"] = torch.stack(ret["prompt_embedding"])

        return ret

    @override
    def compute_loss(self, batch) -> torch.Tensor:
        prompt_embedding = batch["prompt_embedding"]
        latent = batch["encoded_videos"]

        # Shape of prompt_embedding: [B, seq_len, hidden_size]
        # Shape of latent: [B, C, F, H, W]

        patch_size_t = self.state.transformer_config.patch_size_t
        if patch_size_t is not None and latent.shape[2] % patch_size_t != 0:
            raise ValueError(
                "Number of frames in latent must be divisible by patch size, please check your args for training."
            )

        # Add 2 random noise frames at the beginning of frame dimension
        noise_frames = torch.randn(
            latent.shape[0],
            latent.shape[1],
            2,
            latent.shape[3],
            latent.shape[4],
            device=latent.device,
            dtype=latent.dtype,
        )
        latent = torch.cat([noise_frames, latent], dim=2)

        batch_size, num_channels, num_frames, height, width = latent.shape

        # Get prompt embeddings
        _, seq_len, _ = prompt_embedding.shape
        prompt_embedding = prompt_embedding.view(batch_size, seq_len, -1)

        # Sample a random timestep for each sample
        timesteps = torch.randint(
            0, self.components.scheduler.config.num_train_timesteps, (batch_size,), device=self.accelerator.device
        )
        timesteps = timesteps.long()

        # Add noise to latent
        latent = latent.permute(0, 2, 1, 3, 4)  # from [B, C, F, H, W] to [B, F, C, H, W]
        noise = torch.randn_like(latent)
        latent_added_noise = self.components.scheduler.add_noise(latent, noise, timesteps)

        # Prepare rotary embeds
        vae_scale_factor_spatial = 2 ** (len(self.components.vae.config.block_out_channels) - 1)
        transformer_config = self.state.transformer_config
        rotary_emb = (
            self.prepare_rotary_positional_embeddings(
                height=height * vae_scale_factor_spatial,
                width=width * vae_scale_factor_spatial,
                num_frames=num_frames,
                transformer_config=transformer_config,
                vae_scale_factor_spatial=vae_scale_factor_spatial,
                device=self.accelerator.device,
            )
            if transformer_config.use_rotary_positional_embeddings
            else None
        )

        # Predict noise
        predicted_noise = self.components.transformer(
            hidden_states=latent_added_noise,
            encoder_hidden_states=prompt_embedding,
            timestep=timesteps,
            image_rotary_emb=rotary_emb,
            return_dict=False,
        )[0]

        # Denoise
        latent_pred = self.components.scheduler.get_velocity(predicted_noise, latent_added_noise, timesteps)

        alphas_cumprod = self.components.scheduler.alphas_cumprod[timesteps]
        weights = 1 / (1 - alphas_cumprod)
        while len(weights.shape) < len(latent_pred.shape):
            weights = weights.unsqueeze(-1)

        loss = torch.mean((weights * (latent_pred - latent) ** 2).reshape(batch_size, -1), dim=1)
        loss = loss.mean()

        return loss

    @override
    def validation_step(
        self, eval_data: Dict[str, Any], pipe: CogVideoXPipeline
    ) -> List[Tuple[str, Image.Image | List[Image.Image]]]:
        """
        Return the data that needs to be saved. For videos, the data format is List[PIL],
        and for images, the data format is PIL
        """
        prompt, image, video = eval_data["prompt"], eval_data["image"], eval_data["video"]

        video_generate = pipe(
            num_frames=self.state.train_frames,  # since we pad 2 frames in latent, we still use train_frames
            height=self.state.train_height,
            width=self.state.train_width,
            prompt=prompt,
            generator=self.state.generator,
        ).frames[0]
        return [("video", video_generate)]

    def prepare_rotary_positional_embeddings(
        self,
        height: int,
        width: int,
        num_frames: int,
        transformer_config: Dict,
        vae_scale_factor_spatial: int,
        device: torch.device,
    ) -> Tuple[torch.Tensor, torch.Tensor]:
        grid_height = height // (vae_scale_factor_spatial * transformer_config.patch_size)
        grid_width = width // (vae_scale_factor_spatial * transformer_config.patch_size)

        if transformer_config.patch_size_t is None:
            base_num_frames = num_frames
        else:
            base_num_frames = (num_frames + transformer_config.patch_size_t - 1) // transformer_config.patch_size_t

        freqs_cos, freqs_sin = get_3d_rotary_pos_embed(
            embed_dim=transformer_config.attention_head_dim,
            crops_coords=None,
            grid_size=(grid_height, grid_width),
            temporal_size=base_num_frames,
            grid_type="slice",
            max_size=(grid_height, grid_width),
            device=device,
        )

        return freqs_cos, freqs_sin


register("cogvideox-t2v", "lora", CogVideoXT2VLoraTrainer)