improve dev color and quality

mlx_video/generate.py

@@ -545,6 +545,7 @@ def denoise_dev(
     transformer: LTXModel,
     sigmas: mx.array,
     cfg_scale: float = 4.0,
+    cfg_rescale: float = 0.0,
     verbose: bool = True,
     state: Optional[LatentState] = None,
     use_apg: bool = False,
@@ -554,6 +555,9 @@ def denoise_dev(
     """Run denoising loop for dev pipeline with CFG or APG guidance.
 
     Args:
+        cfg_rescale: Rescale factor for CFG (0.0-1.0). Normalizes guided prediction
+                     variance relative to conditional prediction to reduce over-saturation.
+                     PyTorch default is 0.7. Set to 0.0 to disable.
         use_apg: Use Adaptive Projected Guidance instead of standard CFG.
                  APG decomposes guidance into parallel/orthogonal components
                  for more stable I2V generation.
@@ -667,6 +671,14 @@ def denoise_dev(
                 else:
                     # Standard CFG
                     x0_guided_f32 = x0_pos_f32 + (cfg_scale - 1.0) * (x0_pos_f32 - x0_neg_f32)
+
+                # Apply CFG rescale if enabled (std-ratio rescaling to reduce over-saturation)
+                # factor = rescale * (cond_std / pred_std) + (1 - rescale)
+                # pred = pred * factor
+                if cfg_rescale > 0.0:
+                    v_factor = x0_pos_f32.std() / (x0_guided_f32.std() + 1e-8)
+                    v_factor = cfg_rescale * v_factor + (1.0 - cfg_rescale)
+                    x0_guided_f32 = x0_guided_f32 * v_factor
             else:
                 x0_guided_f32 = x0_pos_f32
 
@@ -1381,6 +1393,7 @@ def generate_video(
                 latents, video_positions,
                 video_embeddings_pos, video_embeddings_neg,
                 transformer, sigmas, cfg_scale=cfg_scale,
+                cfg_rescale=cfg_rescale,
                 verbose=verbose, state=video_state,
                 use_apg=use_apg, apg_eta=apg_eta, apg_norm_threshold=apg_norm_threshold
             )
@@ -1477,6 +1490,7 @@ def generate_video(
                 latents, positions,
                 video_embeddings_pos, video_embeddings_neg,
                 transformer, sigmas, cfg_scale=cfg_scale,
+                cfg_rescale=cfg_rescale,
                 verbose=verbose, state=state1,
                 use_apg=use_apg, apg_eta=apg_eta, apg_norm_threshold=apg_norm_threshold
             )