Add chunk_size for long video support, fix cache clearing, add README

- chunk_size input splits input into overlapping segments processed
  independently then stitched, bounding memory for 1000+ frame videos
  while producing identical results to processing all at once
- Fix cache clearing logic: use counter instead of modulo so it triggers
  regardless of batch_size value
- Replace inefficient torch.cat gather with direct tensor slicing
- Add README with usage guide, VRAM recommendations, and full
  attribution to BiM-VFI (Seo, Oh, Kim — CVPR 2025, KAIST VIC Lab)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-02-12 19:08:42 +01:00
parent 993a3a72b1
commit 3e8148b7e2
2 changed files with 183 additions and 39 deletions

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README.md Normal file
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@@ -0,0 +1,88 @@
# ComfyUI BIM-VFI
ComfyUI custom nodes for video frame interpolation using [BiM-VFI](https://github.com/KAIST-VICLab/BiM-VFI) (CVPR 2025). Designed for long videos with thousands of frames — processes them without running out of VRAM.
## Nodes
### Load BIM-VFI Model
Loads the BiM-VFI checkpoint. Auto-downloads from Google Drive on first use to `ComfyUI/models/bim-vfi/`.
| Input | Description |
|-------|-------------|
| **model_path** | Checkpoint file from `models/bim-vfi/` |
| **auto_pyr_level** | Auto-select pyramid level by resolution (&lt;540p=3, 540p=5, 1080p=6, 4K=7) |
| **pyr_level** | Manual pyramid level (3-7), only used when auto is off |
### BIM-VFI Interpolate
Interpolates frames from an image batch.
| Input | Description |
|-------|-------------|
| **images** | Input image batch |
| **model** | Model from the loader node |
| **multiplier** | 2x, 4x, or 8x frame rate (recursive 2x passes) |
| **batch_size** | Frame pairs processed simultaneously (higher = faster, more VRAM) |
| **chunk_size** | Process in segments of N input frames (0 = disabled). Bounds memory for very long videos. Result is identical to processing all at once |
| **keep_device** | Keep model on GPU between pairs (faster, ~200MB constant VRAM) |
| **all_on_gpu** | Keep all intermediate frames on GPU (fast, needs large VRAM) |
| **clear_cache_after_n_frames** | Clear CUDA cache every N pairs to prevent VRAM buildup |
**Output frame count:** 2x = 2N-1, 4x = 4N-3, 8x = 8N-7
## Installation
Clone into your ComfyUI `custom_nodes/` directory:
```bash
cd ComfyUI/custom_nodes
git clone https://github.com/your-user/Comfyui-BIM-VFI.git
```
Dependencies (`gdown`, `cupy`) are auto-installed on first load. The correct `cupy` variant is detected from your PyTorch CUDA version.
To install manually:
```bash
cd Comfyui-BIM-VFI
python install.py
```
### Requirements
- PyTorch with CUDA
- `cupy` (matching your CUDA version)
- `gdown` (for model auto-download)
## VRAM Guide
| VRAM | Recommended settings |
|------|---------------------|
| 8 GB | batch_size=1, chunk_size=500 |
| 24 GB | batch_size=2-4, chunk_size=1000 |
| 48 GB+ | batch_size=4-16, all_on_gpu=true |
| 96 GB+ | batch_size=8-16, all_on_gpu=true, chunk_size=0 |
## Acknowledgments
This project wraps the official [BiM-VFI](https://github.com/KAIST-VICLab/BiM-VFI) implementation by the [KAIST VIC Lab](https://github.com/KAIST-VICLab). The model architecture files in `bim_vfi_arch/` are vendored from their repository with minimal modifications (relative imports, inference-only paths).
**Paper:**
> Wonyong Seo, Jihyong Oh, and Munchurl Kim.
> "BiM-VFI: Bidirectional Motion Field-Guided Frame Interpolation for Video with Non-uniform Motions."
> *IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)*, 2025.
> [[arXiv]](https://arxiv.org/abs/2412.11365) [[Project Page]](https://kaist-viclab.github.io/BiM-VFI_site/) [[GitHub]](https://github.com/KAIST-VICLab/BiM-VFI)
```bibtex
@inproceedings{seo2025bimvfi,
title={BiM-VFI: Bidirectional Motion Field-Guided Frame Interpolation for Video with Non-uniform Motions},
author={Seo, Wonyong and Oh, Jihyong and Kim, Munchurl},
booktitle={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)},
year={2025}
}
```
## License
The BiM-VFI model weights and architecture code are provided by KAIST VIC Lab for **research and education purposes only**. Commercial use requires permission from the principal investigator (Prof. Munchurl Kim, mkimee@kaist.ac.kr). See the [original repository](https://github.com/KAIST-VICLab/BiM-VFI) for details.

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@@ -123,6 +123,10 @@ class BIMVFIInterpolate:
"default": 1, "min": 1, "max": 64, "step": 1,
"tooltip": "Number of frame pairs to process simultaneously. Higher = faster but uses more VRAM. Start with 1, increase until VRAM is full. Recommended: 1 for 8GB, 2-4 for 24GB, 4-16 for 48GB+.",
}),
"chunk_size": ("INT", {
"default": 0, "min": 0, "max": 10000, "step": 1,
"tooltip": "Process input frames in chunks of this size (0=disabled). Each chunk runs all interpolation passes independently then results are stitched seamlessly. Use for very long videos (1000+ frames) to bound memory. Result is identical to processing all at once.",
}),
}
}
@@ -131,47 +135,28 @@ class BIMVFIInterpolate:
FUNCTION = "interpolate"
CATEGORY = "video/BIM-VFI"
def interpolate(self, images, model, multiplier, clear_cache_after_n_frames, keep_device, all_on_gpu, batch_size):
if images.shape[0] < 2:
return (images,)
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
num_passes = {2: 1, 4: 2, 8: 3}[multiplier]
# all_on_gpu implies keep_device
if all_on_gpu:
keep_device = True
# Where to store intermediate frames
storage_device = device if all_on_gpu else torch.device("cpu")
# Convert from ComfyUI [B, H, W, C] to model [B, C, H, W]
frames = images.permute(0, 3, 1, 2).to(storage_device)
# After each 2x pass, frame count = 2*N - 1, so compute total pairs across passes
n = frames.shape[0]
total_steps = 0
for _ in range(num_passes):
total_steps += n - 1
n = 2 * n - 1
pbar = ProgressBar(total_steps)
step = 0
if keep_device:
model.to(device)
def _interpolate_frames(self, frames, model, num_passes, batch_size,
device, storage_device, keep_device, all_on_gpu,
clear_cache_after_n_frames, pbar, step_ref):
"""Run all interpolation passes on a chunk of frames.
Args:
frames: [N, C, H, W] tensor on storage_device
step_ref: list with single int, mutable counter for progress bar
Returns:
Interpolated frames as [M, C, H, W] tensor on storage_device
"""
for pass_idx in range(num_passes):
new_frames = []
num_pairs = frames.shape[0] - 1
pairs_since_clear = 0
for i in range(0, num_pairs, batch_size):
batch_end = min(i + batch_size, num_pairs)
actual_batch = batch_end - i
# Gather batch of pairs
frames0 = torch.cat([frames[j:j+1] for j in range(i, batch_end)], dim=0)
frames1 = torch.cat([frames[j+1:j+2] for j in range(i, batch_end)], dim=0)
frames0 = frames[i:batch_end]
frames1 = frames[i + 1:batch_end + 1]
if not keep_device:
model.to(device)
@@ -182,19 +167,19 @@ class BIMVFIInterpolate:
if not keep_device:
model.to("cpu")
# Interleave: original frame, then interpolated frame
for j in range(actual_batch):
new_frames.append(frames[i + j:i + j + 1])
new_frames.append(mids[j:j+1])
step += actual_batch
pbar.update_absolute(step, total_steps)
step_ref[0] += actual_batch
pbar.update_absolute(step_ref[0])
if not all_on_gpu and (batch_end) % clear_cache_after_n_frames == 0 and torch.cuda.is_available():
pairs_since_clear += actual_batch
if not all_on_gpu and pairs_since_clear >= clear_cache_after_n_frames and torch.cuda.is_available():
clear_backwarp_cache()
torch.cuda.empty_cache()
pairs_since_clear = 0
# Append last frame
new_frames.append(frames[-1:])
frames = torch.cat(new_frames, dim=0)
@@ -202,6 +187,77 @@ class BIMVFIInterpolate:
clear_backwarp_cache()
torch.cuda.empty_cache()
# Convert back to ComfyUI [B, H, W, C], on CPU for ComfyUI
result = frames.cpu().permute(0, 2, 3, 1)
return frames
@staticmethod
def _count_steps(num_frames, num_passes):
"""Count total interpolation steps for a given input frame count."""
n = num_frames
total = 0
for _ in range(num_passes):
total += n - 1
n = 2 * n - 1
return total
def interpolate(self, images, model, multiplier, clear_cache_after_n_frames,
keep_device, all_on_gpu, batch_size, chunk_size):
if images.shape[0] < 2:
return (images,)
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
num_passes = {2: 1, 4: 2, 8: 3}[multiplier]
if all_on_gpu:
keep_device = True
storage_device = device if all_on_gpu else torch.device("cpu")
# Convert from ComfyUI [B, H, W, C] to model [B, C, H, W]
all_frames = images.permute(0, 3, 1, 2).to(storage_device)
total_input = all_frames.shape[0]
# Build chunk boundaries (1-frame overlap between consecutive chunks)
if chunk_size < 2 or chunk_size >= total_input:
chunks = [(0, total_input)]
else:
chunks = []
start = 0
while start < total_input - 1:
end = min(start + chunk_size, total_input)
chunks.append((start, end))
start = end - 1 # overlap by 1 frame
if end == total_input:
break
# Calculate total progress steps across all chunks
total_steps = sum(self._count_steps(ce - cs, num_passes) for cs, ce in chunks)
pbar = ProgressBar(total_steps)
step_ref = [0]
if keep_device:
model.to(device)
result_chunks = []
for chunk_idx, (chunk_start, chunk_end) in enumerate(chunks):
chunk_frames = all_frames[chunk_start:chunk_end].clone()
chunk_result = self._interpolate_frames(
chunk_frames, model, num_passes, batch_size,
device, storage_device, keep_device, all_on_gpu,
clear_cache_after_n_frames, pbar, step_ref,
)
# Skip first frame of subsequent chunks (duplicate of previous chunk's last frame)
if chunk_idx > 0:
chunk_result = chunk_result[1:]
# Move completed chunk to CPU to bound memory when chunking
if len(chunks) > 1:
chunk_result = chunk_result.cpu()
result_chunks.append(chunk_result)
result = torch.cat(result_chunks, dim=0)
# Convert back to ComfyUI [B, H, W, C], on CPU
result = result.cpu().permute(0, 2, 3, 1)
return (result,)