Reshape the empty latent image to the right amount of channels if needed.

comfy/latent_formats.py

@@ -2,6 +2,7 @@ import torch
 
 class LatentFormat:
     scale_factor = 1.0
+    latent_channels = 4
     latent_rgb_factors = None
     taesd_decoder_name = None
 
@@ -72,6 +73,7 @@ class SD_X4(LatentFormat):
         ]
 
 class SC_Prior(LatentFormat):
+    latent_channels = 16
     def __init__(self):
         self.scale_factor = 1.0
         self.latent_rgb_factors = [

comfy/sample.py

@@ -24,6 +24,12 @@ def prepare_noise(latent_image, seed, noise_inds=None):
     noises = torch.cat(noises, axis=0)
     return noises
 
+def fix_empty_latent_channels(model, latent_image):
+    latent_channels = model.get_model_object("latent_format").latent_channels #Resize the empty latent image so it has the right number of channels
+    if latent_channels != latent_image.shape[1] and torch.count_nonzero(latent_image) == 0:
+        latent_image = comfy.utils.repeat_to_batch_size(latent_image, latent_channels, dim=1)
+    return latent_image
+
 def prepare_sampling(model, noise_shape, positive, negative, noise_mask):
     logging.warning("Warning: comfy.sample.prepare_sampling isn't used anymore and can be removed")
     return model, positive, negative, noise_mask, []

comfy/utils.py

@@ -249,11 +249,11 @@ def unet_to_diffusers(unet_config):
 
     return diffusers_unet_map
 
-def repeat_to_batch_size(tensor, batch_size):
+def repeat_to_batch_size(tensor, batch_size, dim=0):
-    if tensor.shape[0] > batch_size:
+    if tensor.shape[dim] > batch_size:
-        return tensor[:batch_size]
+        return tensor.narrow(dim, 0, batch_size)
-    elif tensor.shape[0] < batch_size:
+    elif tensor.shape[dim] < batch_size:
-        return tensor.repeat([math.ceil(batch_size / tensor.shape[0])] + [1] * (len(tensor.shape) - 1))[:batch_size]
+        return tensor.repeat(dim * [1] + [math.ceil(batch_size / tensor.shape[dim])] + [1] * (len(tensor.shape) - 1 - dim)).narrow(dim, 0, batch_size)
     return tensor
 
 def resize_to_batch_size(tensor, batch_size):

comfy_extras/nodes_custom_sampler.py

@@ -380,6 +380,7 @@ class SamplerCustom:
     def sample(self, model, add_noise, noise_seed, cfg, positive, negative, sampler, sigmas, latent_image):
         latent = latent_image
         latent_image = latent["samples"]
+        latent_image = comfy.sample.fix_empty_latent_channels(model, latent_image)
         if not add_noise:
             noise = Noise_EmptyNoise().generate_noise(latent)
         else:
@@ -538,6 +539,7 @@ class SamplerCustomAdvanced:
     def sample(self, noise, guider, sampler, sigmas, latent_image):
         latent = latent_image
         latent_image = latent["samples"]
+        latent_image = comfy.sample.fix_empty_latent_channels(guider.model_patcher, latent_image)
 
         noise_mask = None
         if "noise_mask" in latent:

nodes.py

@@ -1299,6 +1299,8 @@ class SetLatentNoiseMask:
 
 def common_ksampler(model, seed, steps, cfg, sampler_name, scheduler, positive, negative, latent, denoise=1.0, disable_noise=False, start_step=None, last_step=None, force_full_denoise=False):
     latent_image = latent["samples"]
+    latent_image = comfy.sample.fix_empty_latent_channels(model, latent_image)
+
     if disable_noise:
         noise = torch.zeros(latent_image.size(), dtype=latent_image.dtype, layout=latent_image.layout, device="cpu")
     else: