Fix long sequence NaN issue

Author: flyingblackshark

src/maxdiffusion/pipelines/ltx2/ltx2_pipeline.py

@@ -1347,7 +1347,7 @@ def __call__(
     video_sequence_length *= (height // self.vae_spatial_compression_ratio) * (width // self.vae_spatial_compression_ratio)
 
     mu = calculate_shift(
-        video_sequence_length,
+        4096,
         self.scheduler.config.get("base_image_seq_len", 1024),
         self.scheduler.config.get("max_image_seq_len", 4096),
         self.scheduler.config.get("base_shift", 0.95),