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ryanontheinside-ComfyUI_Rea…/stream_sampler.py
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2025-02-14 18:43:05 -05:00

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Python

import torch
from .base.control_base import ControlNodeBase
import comfy.model_management
import comfy.samplers
import random
import math
class StreamBatchSampler(ControlNodeBase):
"""Implements batched denoising for faster inference by processing multiple frames in parallel at different denoising steps"""
RETURN_TYPES = ("SAMPLER",)
FUNCTION = "update"
CATEGORY = "real-time/sampling"
@classmethod
def INPUT_TYPES(cls):
inputs = super().INPUT_TYPES()
inputs["required"].update({
"num_steps": ("INT", {
"default": 4,
"min": 1,
"max": 10,
"step": 1,
"tooltip": "Number of denoising steps. Should match the frame buffer size."
}),
"use_cfg": ("BOOLEAN", {
"default": False,
"tooltip": "Whether to use classifier-free guidance optimizations"
}),
"cfg_type": (["none", "full", "self", "initialize"], {
"default": "self",
"tooltip": "Type of CFG to use: none (no guidance), full (standard), self (memory efficient), or initialize (memory efficient with initialization)"
}),
"guidance_scale": ("FLOAT", {
"default": 1.2,
"min": 1.0,
"max": 20.0,
"step": 0.1,
"tooltip": "CFG guidance scale - 1.0 means no guidance"
}),
"delta": ("FLOAT", {
"default": 1.0,
"min": 0.0,
"max": 5.0,
"step": 0.1,
"tooltip": "Delta parameter for self/initialize CFG types"
}),
"use_similarity_filter": ("BOOLEAN", {
"default": False,
"tooltip": "Whether to use similarity filtering to skip similar frames"
}),
"similarity_threshold": ("FLOAT", {
"default": 0.98,
"min": 0.0,
"max": 1.0,
"step": 0.01,
"tooltip": "Threshold for similarity filtering - higher means more frames are skipped"
}),
"max_skip_frames": ("INT", {
"default": 10,
"min": 1,
"max": 100,
"step": 1,
"tooltip": "Maximum number of consecutive frames to skip"
}),
})
inputs["optional"] = {
"prompt": ("STRING", {
"multiline": True,
"default": "",
"tooltip": "Text prompt to use for cross-attention optimization. If provided, enables KV caching."
}),
}
return inputs
def __init__(self):
super().__init__()
self.num_steps = None
self.frame_buffer = []
self.x_t_latent_buffer = None
self.stock_noise = None
# Add CFG state
self.use_cfg = False
self.cfg_type = "self"
self.guidance_scale = 1.2
self.delta = 1.0
# Add cross attention state
self.prompt = ""
self.last_prompt = None
self.kv_cache = None
self.cross_attention_hook = None
self.last_model_hash = None
# Add similarity filter state
self.use_similarity_filter = False
self.similarity_filter = None
def process_with_cfg(self, model, x, sigma_batch, extra_args):
"""Apply classifier-free guidance based on current cfg_type"""
if not self.use_cfg or self.cfg_type == "none" or self.guidance_scale <= 1.0:
# No guidance - process batch normally
return model(x, sigma_batch, **extra_args)
# Apply CFG based on type
if self.cfg_type == "full":
# Double the batch for cond/uncond
x_double = torch.cat([x, x], dim=0)
sigma_double = torch.cat([sigma_batch, sigma_batch], dim=0)
model_output = model(x_double, sigma_double, **extra_args)
noise_pred_uncond, noise_pred_text = model_output.chunk(2)
elif self.cfg_type == "initialize":
# Add single uncond at start
x_plus_uc = torch.cat([x[0:1], x], dim=0)
sigma_plus_uc = torch.cat([sigma_batch[0:1], sigma_batch], dim=0)
model_output = model(x_plus_uc, sigma_plus_uc, **extra_args)
noise_pred_uncond = model_output[0:1]
noise_pred_text = model_output[1:]
# Update stock noise with uncond prediction
self.stock_noise = noise_pred_uncond[0].clone()
else: # self
# Use stock noise for uncond
model_output = model(x, sigma_batch, **extra_args)
noise_pred_text = model_output
noise_pred_uncond = self.stock_noise.unsqueeze(0).expand_as(noise_pred_text) * self.delta
# Combine predictions with guidance
return noise_pred_uncond + self.guidance_scale * (noise_pred_text - noise_pred_uncond)
def setup_cross_attention(self, model, prompt):
"""Set up cross attention optimization for the model"""
if not prompt: # Don't use optimization if no prompt provided
return model
print(f"[StreamBatchSampler] Setting up cross attention with prompt: {prompt}")
def optimized_attention_forward(module, x, context=None, mask=None):
"""Optimized cross attention with KV caching"""
batch_size = x.shape[0]
# Generate query from input
q = module.to_q(x)
# Check if we need to recompute KV cache
if self.kv_cache is None or self.last_prompt != prompt:
print("[StreamBatchSampler] Computing new KV cache")
k = module.to_k(context)
v = module.to_v(context)
self.kv_cache = (k, v)
self.last_prompt = prompt
else:
print("[StreamBatchSampler] Using cached KV pairs")
k, v = self.kv_cache
# Handle batch size expansion if needed
if k.shape[0] == 1 and batch_size > 1:
k = k.expand(batch_size, -1, -1)
v = v.expand(batch_size, -1, -1)
# Reshape for attention
head_dim = q.shape[-1] // module.heads
q = q.view(batch_size, -1, module.heads, head_dim).transpose(1, 2)
k = k.view(-1, k.shape[1], module.heads, head_dim).transpose(1, 2)
v = v.view(-1, v.shape[1], module.heads, head_dim).transpose(1, 2)
# Compute attention
scale = 1.0 / math.sqrt(head_dim)
scores = torch.matmul(q, k.transpose(-2, -1)) * scale
if mask is not None:
scores = scores + mask
attn = torch.softmax(scores, dim=-1)
out = torch.matmul(attn, v)
# Reshape output
out = out.transpose(1, 2).reshape(batch_size, -1, module.heads * head_dim)
return module.to_out[0](out)
def create_cross_attn_patch(module, input, output):
"""Hook to replace cross attention modules with optimized version"""
if isinstance(module, torch.nn.Module) and hasattr(module, "to_q"):
if not hasattr(module, "_original_forward"):
module._original_forward = module.forward
module.forward = lambda *args, **kwargs: optimized_attention_forward(module, *args, **kwargs)
return output
# Get the actual model from the sampler
if hasattr(model, "model"):
unet = model.model
else:
print("[StreamBatchSampler] Warning: Could not find UNet model in sampler")
return model
# Only set up hooks if prompt has changed
model_hash = hash(str(unet))
if model_hash != self.last_model_hash or self.last_prompt != prompt:
print("[StreamBatchSampler] Setting up new cross attention hooks")
# Remove old hooks if they exist
if self.cross_attention_hook is not None:
self.cross_attention_hook.remove()
# Register hooks on cross attention blocks
def register_hooks(module):
if isinstance(module, torch.nn.Module) and hasattr(module, "to_q"):
self.cross_attention_hook = module.register_forward_hook(create_cross_attn_patch)
unet.apply(register_hooks)
self.last_model_hash = model_hash
return model
def sample(self, model, noise, sigmas, extra_args=None, callback=None, disable=None):
"""Sample with staggered batch denoising steps"""
extra_args = {} if extra_args is None else extra_args
print(f"[StreamBatchSampler] Starting sampling with {len(sigmas)-1} steps")
# Set up cross attention optimization if prompt provided
if self.prompt:
model = self.setup_cross_attention(model, self.prompt)
print("[StreamBatchSampler] Cross attention optimization enabled")
else:
print("[StreamBatchSampler] Cross attention optimization disabled (no prompt)")
if self.use_cfg:
print(f"[StreamBatchSampler] CFG enabled - type: {self.cfg_type}, scale: {self.guidance_scale}, delta: {self.delta}")
# Get number of frames in batch and available sigmas
batch_size = noise.shape[0]
num_sigmas = len(sigmas) - 1 # Subtract 1 because last sigma is the target (0.0)
print(f"[StreamBatchSampler] Input sigmas: {sigmas}")
print(f"[StreamBatchSampler] Input noise shape: {noise.shape}, min: {noise.min():.3f}, max: {noise.max():.3f}")
# Verify batch size matches number of timesteps
if batch_size != num_sigmas:
raise ValueError(f"Batch size ({batch_size}) must match number of timesteps ({num_sigmas})")
# Pre-compute alpha and beta terms
alpha_prod_t = (sigmas[:-1] / sigmas[0]).view(-1, 1, 1, 1) # [B,1,1,1]
beta_prod_t = (1 - alpha_prod_t)
print(f"[StreamBatchSampler] Alpha values: {alpha_prod_t.view(-1)}")
print(f"[StreamBatchSampler] Beta values: {beta_prod_t.view(-1)}")
# Initialize stock noise if needed
if self.stock_noise is None:
self.stock_noise = torch.randn_like(noise[0]) # Random noise instead of zeros
print(f"[StreamBatchSampler] Initialized random stock noise with shape: {self.stock_noise.shape}")
# Scale noise for each frame based on its sigma
scaled_noise = []
for i in range(batch_size):
frame_noise = noise[i] + self.stock_noise * sigmas[i] # Add scaled noise to input
scaled_noise.append(frame_noise)
x = torch.stack(scaled_noise, dim=0)
print(f"[StreamBatchSampler] Scaled noise shape: {x.shape}, min: {x.min():.3f}, max: {x.max():.3f}")
# Initialize frame buffer if needed
if self.x_t_latent_buffer is None and num_sigmas > 1:
self.x_t_latent_buffer = x[0].clone() # Initialize with noised first frame
print(f"[StreamBatchSampler] Initialized buffer with shape: {self.x_t_latent_buffer.shape}")
# Use buffer for first frame to maintain temporal consistency
if num_sigmas > 1:
x = torch.cat([self.x_t_latent_buffer.unsqueeze(0), x[1:]], dim=0)
print(f"[StreamBatchSampler] Combined with buffer, shape: {x.shape}")
# Run model on entire batch at once
with torch.no_grad():
# Process all frames in parallel
sigma_batch = sigmas[:-1]
print(f"[StreamBatchSampler] Using sigmas for denoising: {sigma_batch}")
# Process with or without CFG
if self.use_cfg:
denoised_batch = self.process_with_cfg(model, x, sigma_batch, extra_args)
else:
denoised_batch = model(x, sigma_batch, **extra_args)
print(f"[StreamBatchSampler] Denoised batch shape: {denoised_batch.shape}")
print(f"[StreamBatchSampler] Denoised stats - min: {denoised_batch.min():.3f}, max: {denoised_batch.max():.3f}")
# Update buffer with intermediate results
if num_sigmas > 1:
# Store result from first frame as buffer for next iteration
self.x_t_latent_buffer = denoised_batch[0].clone()
print(f"[StreamBatchSampler] Updated buffer with shape: {self.x_t_latent_buffer.shape}")
# Return result from last frame
x_0_pred_out = denoised_batch[-1].unsqueeze(0)
else:
x_0_pred_out = denoised_batch
self.x_t_latent_buffer = None
# Apply similarity filter if enabled
if self.use_similarity_filter:
if self.similarity_filter is None:
from .controls.similar_image_filter import SimilarImageFilter
self.similarity_filter = SimilarImageFilter(
threshold=self.similarity_threshold,
max_skip_frame=self.max_skip_frames
)
filtered_out = self.similarity_filter(x_0_pred_out)
if filtered_out is not None:
x_0_pred_out = filtered_out
print("[StreamBatchSampler] Frame passed similarity filter")
else:
print("[StreamBatchSampler] Frame skipped by similarity filter")
# Call callback if provided
if callback is not None:
callback({'x': x_0_pred_out, 'i': 0, 'sigma': sigmas[0], 'sigma_hat': sigmas[0], 'denoised': denoised_batch[-1:]})
return x_0_pred_out
def update(self, num_steps=4, use_cfg=False, cfg_type="self", guidance_scale=1.2, delta=1.0, prompt="",
use_similarity_filter=False, similarity_threshold=0.98, max_skip_frames=10, always_execute=True):
"""Create sampler with specified settings"""
self.num_steps = num_steps
self.use_cfg = use_cfg
self.cfg_type = cfg_type
self.guidance_scale = guidance_scale
self.delta = delta
self.prompt = prompt
# Update similarity filter settings
self.use_similarity_filter = use_similarity_filter
self.similarity_threshold = similarity_threshold
self.max_skip_frames = max_skip_frames
if self.similarity_filter is not None:
self.similarity_filter.set_threshold(similarity_threshold)
self.similarity_filter.set_max_skip_frame(max_skip_frames)
# Create sampler without extra_args - we use self.prompt directly in sample()
sampler = comfy.samplers.KSAMPLER(self.sample)
return (sampler,)
class StreamScheduler(ControlNodeBase):
"""Implements StreamDiffusion's efficient timestep selection"""
RETURN_TYPES = ("SIGMAS",)
FUNCTION = "update"
CATEGORY = "real-time/sampling"
@classmethod
def INPUT_TYPES(cls):
inputs = super().INPUT_TYPES()
inputs["required"].update({
"model": ("MODEL",),
"t_index_list": ("STRING", {
"default": "32,45",
"tooltip": "Comma-separated list of timesteps to actually use for denoising. Examples: '32,45' for img2img or '0,16,32,45' for txt2img"
}),
"num_inference_steps": ("INT", {
"default": 50,
"min": 1,
"max": 1000,
"step": 1,
"tooltip": "Total number of timesteps in schedule. StreamDiffusion uses 50 by default. Only timesteps specified in t_index_list are actually used."
}),
})
return inputs
def update(self, model, t_index_list="32,45", num_inference_steps=50, always_execute=True):
# Get model's sampling parameters
model_sampling = model.get_model_object("model_sampling")
# Parse timestep list
try:
t_index_list = [int(t.strip()) for t in t_index_list.split(",")]
except ValueError as e:
print(f"Error parsing timesteps: {e}. Using default [32,45]")
t_index_list = [32, 45]
# Create full schedule using normal scheduler
full_sigmas = comfy.samplers.normal_scheduler(model_sampling, num_inference_steps)
# Select only the sigmas at our desired indices, but in reverse order
# This ensures we go from high noise to low noise
selected_sigmas = []
for t in sorted(t_index_list, reverse=True): # Sort in reverse to go from high noise to low
if t < 0 or t >= num_inference_steps:
print(f"Warning: timestep {t} out of range [0,{num_inference_steps}), skipping")
continue
selected_sigmas.append(float(full_sigmas[t]))
# Add final sigma
selected_sigmas.append(0.0)
# Convert to tensor and move to appropriate device
selected_sigmas = torch.FloatTensor(selected_sigmas).to(comfy.model_management.get_torch_device())
return (selected_sigmas,)
class StreamFrameBuffer(ControlNodeBase):
"""Accumulates frames to enable staggered batch denoising like StreamDiffusion"""
RETURN_TYPES = ("LATENT",)
FUNCTION = "update"
CATEGORY = "real-time/sampling"
@classmethod
def INPUT_TYPES(cls):
inputs = super().INPUT_TYPES()
inputs["required"].update({
"latent": ("LATENT",),
"buffer_size": ("INT", {
"default": 4,
"min": 1,
"max": 10,
"step": 1,
"tooltip": "Number of frames to buffer before starting batch processing. Should match number of denoising steps."
}),
})
return inputs
def __init__(self):
super().__init__()
self.frame_buffer = [] # List to store incoming frames
self.buffer_size = None
def update(self, latent, buffer_size=4, always_execute=True):
"""Add new frame to buffer and return batch when ready"""
self.buffer_size = buffer_size
# Extract latent tensor from input and remove batch dimension if present
x = latent["samples"]
if x.dim() == 4: # [B,C,H,W]
x = x.squeeze(0) # Remove batch dimension -> [C,H,W]
# Add new frame to buffer
if len(self.frame_buffer) == 0:
# First frame - initialize buffer with copies
self.frame_buffer = [x.clone() for _ in range(self.buffer_size)]
print(f"[StreamFrameBuffer] Initialized buffer with {self.buffer_size} copies of first frame")
else:
# Shift frames forward and add new frame
self.frame_buffer.pop(0) # Remove oldest frame
self.frame_buffer.append(x.clone()) # Add new frame
print(f"[StreamFrameBuffer] Added new frame to buffer")
# Stack frames into batch
batch = torch.stack(self.frame_buffer, dim=0) # [B,C,H,W]
print(f"[StreamFrameBuffer] Created batch with shape: {batch.shape}")
# Return as latent dict
return ({"samples": batch},)