[bugfix]: fix VAE temporal tiling blend corruption in tiled_encode

examples/train/configs/overfit_hunyuan_t2v.yaml

@@ -0,0 +1,78 @@
+# HunyuanVideo T2V overfitting test config.
+#
+# Overfits on 3 short videos (480x832, 77 frames) to verify the
+# training pipeline works end-to-end.
+#
+# Preprocess data first:
+#   CUDA_VISIBLE_DEVICES=0 python scripts/preprocess_hunyuan_overfit.py
+#
+# Run:
+#   bash examples/train/run.sh examples/train/configs/overfit_hunyuan_t2v.yaml
+
+models:
+  student:
+    _target_: fastvideo.train.models.hunyuan.HunyuanModel
+    init_from: hunyuanvideo-community/HunyuanVideo
+    trainable: true
+    enable_gradient_checkpointing_type: full
+
+method:
+  _target_: fastvideo.train.methods.fine_tuning.finetune.FineTuneMethod
+
+training:
+  distributed:
+    num_gpus: 8
+    sp_size: 1
+    tp_size: 1
+    hsdp_replicate_dim: 1
+    hsdp_shard_dim: 8
+
+  data:
+    data_path: data/hunyuan_overfit_preprocessed
+    dataloader_num_workers: 0
+    train_batch_size: 1
+    training_cfg_rate: 0.0
+    seed: 42
+    num_latent_t: 20
+    num_height: 480
+    num_width: 832
+    num_frames: 77
+
+  optimizer:
+    learning_rate: 5.0e-5
+    betas: [0.9, 0.999]
+    weight_decay: 0.0
+    lr_scheduler: constant
+    lr_warmup_steps: 0
+
+  loop:
+    max_train_steps: 300
+    gradient_accumulation_steps: 1
+
+  checkpoint:
+    output_dir: outputs/hunyuan_overfit
+    training_state_checkpointing_steps: 50
+    checkpoints_total_limit: 2
+
+  tracker:
+    project_name: fastvideo_hunyuan
+    run_name: hunyuan_overfit
+
+  model:
+    precondition_outputs: true
+    enable_gradient_checkpointing_type: full
+
+callbacks:
+  grad_clip:
+    _target_: fastvideo.train.callbacks.grad_clip.GradNormClipCallback
+    max_grad_norm: 1.0
+  validation:
+    _target_: fastvideo.train.callbacks.validation.ValidationCallback
+    pipeline_target: fastvideo.pipelines.basic.hunyuan.hunyuan_pipeline.HunyuanVideoPipeline
+    dataset_file: data/hunyuan_overfit_preprocessed/validation_prompts.json
+    every_steps: 50
+    sampling_steps: [50]
+    guidance_scale: 1.0
+
+pipeline:
+  flow_shift: 7

fastvideo/models/vaes/common.py

@@ -364,10 +364,15 @@ def tiled_encode(self, x: torch.Tensor) -> torch.Tensor:
             if i > 0:
                 tile = tile[:, :, 1:, :, :]
             row.append(tile)
+        blend_latent_num_frames = max(
+            1,
+            self.blend_num_frames // self.temporal_compression_ratio,
+        )
         result_row = []
         for i, tile in enumerate(row):
             if i > 0:
-                tile = self.blend_t(row[i - 1], tile, self.blend_num_frames)
+                tile = self.blend_t(row[i - 1], tile,
+                                    blend_latent_num_frames)
                 result_row.append(
                     tile[:, :, :tile_latent_stride_num_frames, :, :])
             else:

fastvideo/pipelines/preprocess/preprocess_hunyuan_overfit.py

@@ -0,0 +1,206 @@
+# SPDX-License-Identifier: Apache-2.0
+"""Preprocess HunyuanVideo overfit data into parquet format.
+
+Encodes videos with HunyuanVideo VAE and captions with dual text
+encoders (LLaMA + CLIP) into the t2v parquet schema expected by
+the training framework.
+
+Usage:
+    CUDA_VISIBLE_DEVICES=0 python scripts/preprocess_hunyuan_overfit.py
+"""
+
+import glob
+import json
+import os
+
+import cv2
+import numpy as np
+import pyarrow as pa
+import pyarrow.parquet as pq
+import torch
+from safetensors.torch import load_file as safetensors_load_file
+
+from fastvideo.configs.models.vaes import HunyuanVAEConfig
+from fastvideo.configs.pipelines.hunyuan import (
+    clip_preprocess_text,
+    clip_postprocess_text,
+    llama_preprocess_text,
+    llama_postprocess_text,
+)
+from fastvideo.dataset.dataloader.schema import pyarrow_schema_t2v
+from fastvideo.models.vaes.hunyuanvae import AutoencoderKLHunyuanVideo
+from fastvideo.utils import maybe_download_model
+
+# --- Config ---
+NUM_FRAMES = 77  # 4k+1 for temporal compression ratio 4
+MAX_HEIGHT = 480
+MAX_WIDTH = 832
+TRAIN_FPS = 16.0
+
+DATA_DIR = "data/hunyuan_overfit"
+OUTPUT_DIR = "data/hunyuan_overfit_preprocessed"
+
+
+def load_video(path: str, num_frames: int) -> torch.Tensor:
+    """Load video as [1, C, T, H, W] in [-1, 1]."""
+    cap = cv2.VideoCapture(path)
+    frames: list[np.ndarray] = []
+    while len(frames) < num_frames:
+        ret, frame = cap.read()
+        if not ret:
+            break
+        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
+        frames.append(frame)
+    cap.release()
+
+    if len(frames) < num_frames:
+        # Repeat last frame to fill
+        while len(frames) < num_frames:
+            frames.append(frames[-1])
+
+    frames = frames[:num_frames]
+    video = np.stack(frames, axis=0)
+    video = torch.from_numpy(video).float()
+    video = video / 127.5 - 1.0  # [0,255] -> [-1,1]
+    video = video.permute(3, 0, 1, 2).unsqueeze(0)  # [1,C,T,H,W]
+    return video
+
+
+def main() -> None:
+    device = torch.device("cuda:0")
+    model_path = maybe_download_model("hunyuanvideo-community/HunyuanVideo")
+    vae_path = os.path.join(model_path, "vae")
+
+    os.makedirs(OUTPUT_DIR, exist_ok=True)
+
+    # Load captions
+    with open(os.path.join(DATA_DIR, "videos2caption.json")) as f:
+        caption_data = json.load(f)
+
+    # --- Load VAE ---
+    print("Loading HunyuanVideo VAE...")
+    vae_config = HunyuanVAEConfig()
+    vae_config.load_encoder = True
+    vae_config.load_decoder = False
+    vae = AutoencoderKLHunyuanVideo(vae_config)
+    sf_files = glob.glob(os.path.join(vae_path, "*.safetensors"))
+    loaded = {}
+    for sf_file in sf_files:
+        loaded.update(safetensors_load_file(sf_file))
+    vae.load_state_dict(loaded, strict=False)
+    vae = vae.to(device=device, dtype=torch.float16).eval()
+    vae.use_parallel_tiling = False
+    print(f"VAE loaded ({sum(p.numel() for p in vae.parameters())/1e6:.0f}M)")
+
+    # --- Load text encoders ---
+    print("Loading LLaMA text encoder...")
+    from transformers import AutoTokenizer, CLIPTextModel, LlamaModel
+    from fastvideo.configs.pipelines.hunyuan import (LlamaConfig, CLIPTextConfig)
+
+    llama_cfg = LlamaConfig()
+    llama_tok = AutoTokenizer.from_pretrained(os.path.join(model_path, "tokenizer"))
+    llama_enc = LlamaModel.from_pretrained(
+        os.path.join(model_path, "text_encoder"),
+        torch_dtype=torch.float16,
+    ).to(device).eval()
+    llama_tok_kwargs = dict(llama_cfg.tokenizer_kwargs)
+
+    print("Loading CLIP text encoder...")
+    clip_cfg = CLIPTextConfig()
+    clip_tok = AutoTokenizer.from_pretrained(os.path.join(model_path, "tokenizer_2"))
+    clip_enc = CLIPTextModel.from_pretrained(
+        os.path.join(model_path, "text_encoder_2"),
+        torch_dtype=torch.float16,
+    ).to(device).eval()
+    clip_tok_kwargs = dict(clip_cfg.tokenizer_kwargs)
+
+    # --- Process each video ---
+    records = []
+    for item in caption_data:
+        video_name = item["path"]
+        caption = item["cap"][0]
+        video_path = os.path.join(DATA_DIR, "videos", video_name)
+
+        print(f"\nProcessing: {video_name}")
+        print(f"  Caption: {caption[:80]}...")
+
+        # Encode video
+        video = load_video(video_path, NUM_FRAMES).to(device=device, dtype=torch.float16)
+        print(f"  Video shape: {video.shape}")
+
+        with torch.no_grad():
+            latent_dist = vae.encode(video)
+            # Cast to fp32 — dataloader hardcodes np.float32
+            latent = latent_dist.mean.squeeze(0).float().cpu()
+        print(f"  Latent shape: {latent.shape}")
+
+        # Encode text with LLaMA
+        llama_text = llama_preprocess_text(caption)
+        with torch.no_grad():
+            llama_inputs = llama_tok(llama_text, **llama_tok_kwargs).to(device)
+            llama_out = llama_enc(**llama_inputs, output_hidden_states=True)
+            llama_embeds = llama_postprocess_text(llama_out).squeeze(0)  # [seq, dim]
+
+        # Encode text with CLIP
+        clip_text = clip_preprocess_text(caption)
+        with torch.no_grad():
+            clip_inputs = clip_tok(clip_text, **clip_tok_kwargs).to(device)
+            clip_out = clip_enc(**clip_inputs)
+            clip_pooled = clip_postprocess_text(clip_out).squeeze(0)  # [dim]
+
+        # Combine: [pooled_clip_row, llama_embeds]
+        llama_dim = llama_embeds.shape[-1]
+        pooled_row = torch.zeros(llama_dim, device=device, dtype=torch.float16)
+        pooled_row[:clip_pooled.shape[-1]] = clip_pooled
+        text_embedding = torch.cat(
+            [pooled_row.unsqueeze(0), llama_embeds],
+            dim=0,
+        ).float().cpu()  # [seq+1, dim]
+        print(f"  Text embedding shape: {text_embedding.shape}")
+
+        record = {
+            "id": video_name,
+            "vae_latent_bytes": latent.numpy().tobytes(),
+            "vae_latent_shape": list(latent.shape),
+            "vae_latent_dtype": str(latent.dtype).replace("torch.", ""),
+            "text_embedding_bytes": text_embedding.numpy().tobytes(),
+            "text_embedding_shape": list(text_embedding.shape),
+            "text_embedding_dtype": str(text_embedding.dtype).replace("torch.", ""),
+            "file_name": video_name,
+            "caption": caption,
+            "media_type": "video",
+            "width": MAX_WIDTH,
+            "height": MAX_HEIGHT,
+            "num_frames": NUM_FRAMES,
+            "duration_sec": NUM_FRAMES / TRAIN_FPS,
+            "fps": TRAIN_FPS,
+        }
+        records.append(record)
+
+    # Clean up encoders
+    del llama_enc, llama_tok, clip_enc, clip_tok, vae
+
+    # Write parquet
+    table = pa.table(
+        {k: [r[k] for r in records]
+         for k in records[0]},
+        schema=pyarrow_schema_t2v,
+    )
+    output_path = os.path.join(OUTPUT_DIR, "data_00000.parquet")
+    pq.write_table(table, output_path)
+    print(f"\nWrote {len(records)} records to {output_path}")
+
+    # Write validation prompts for callback
+    # Wrap in "data" key — ValidationDataset expects field="data"
+    # Use "caption" field — ValidationDataset aliases it to "prompt"
+    val_prompts = {"data": [{"caption": item["cap"][0]} for item in caption_data]}
+    val_path = os.path.join(OUTPUT_DIR, "validation_prompts.json")
+    with open(val_path, "w") as f:
+        json.dump(val_prompts, f, indent=2)
+    print(f"Wrote validation prompts to {val_path}")
+
+    print("\nDone! Use data_path: " + OUTPUT_DIR + " in training config.")
+
+
+if __name__ == "__main__":
+    main()