[Cog] some minor fixes and nits

src/diffusers/pipelines/cogvideo/pipeline_cogvideox_video2video.py

@@ -206,6 +206,11 @@ def __init__(
         self.register_modules(
             tokenizer=tokenizer, text_encoder=text_encoder, vae=vae, transformer=transformer, scheduler=scheduler
         )
+        self.latents_in_channels = (
+            self.transformer.config.in_channels
+            if hasattr(self, "transformer") and self.transformer is not None
+            else 16
+        )
         self.vae_scale_factor_spatial = (
             2 ** (len(self.vae.config.block_out_channels) - 1) if hasattr(self, "vae") and self.vae is not None else 8
         )
@@ -657,14 +662,16 @@ def __call__(
 
         # 1. Check inputs. Raise error if not correct
         self.check_inputs(
-            prompt,
-            height,
-            width,
-            strength,
-            negative_prompt,
-            callback_on_step_end_tensor_inputs,
-            prompt_embeds,
-            negative_prompt_embeds,
+            prompt=prompt,
+            height=height,
+            width=width,
+            strength=strength,
+            negative_prompt=negative_prompt,
+            callback_on_step_end_tensor_inputs=callback_on_step_end_tensor_inputs,
+            video=video,
+            latents=latents,
+            prompt_embeds=prompt_embeds,
+            negative_prompt_embeds=negative_prompt_embeds,
         )
         self._guidance_scale = guidance_scale
         self._interrupt = False
@@ -709,7 +716,7 @@ def __call__(
             video = self.video_processor.preprocess_video(video, height=height, width=width)
             video = video.to(device=device, dtype=prompt_embeds.dtype)
 
-        latent_channels = self.transformer.config.in_channels
+        latent_channels = self.latents_in_channels
         latents = self.prepare_latents(
             video,
             batch_size * num_videos_per_prompt,