update doc

docs/EN/source/method_tutorials/changing_resolution.md

@@ -47,7 +47,7 @@ You can refer to the scripts [here](https://github.com/ModelTC/LightX2V/blob/mai
 }
 ```
 
-This means a total of 50 steps, with resolution at 0.75x original resolution from step 0 to 25, and original resolution from step 26 to the final step.
+This means a total of 50 steps, with resolution at 0.75x original resolution from step 1 to 25, and original resolution from step 26 to the final step.
 
 ### Example 2:
 ```
@@ -59,4 +59,8 @@ This means a total of 50 steps, with resolution at 0.75x original resolution fro
 }
 ```
 
-This means a total of 50 steps, with original resolution from step 0 to 10, 0.75x original resolution from step 11 to 35, and original resolution from step 36 to the final step.
+This means a total of 50 steps, with original resolution from step 1 to 10, 0.75x original resolution from step 11 to 35, and original resolution from step 36 to the final step.
+
+Generally, if `changing_resolution_steps` is [A, B, C], the denoising starts at step 1, and the total number of steps is X, then the inference process will be divided into four segments.
+
+Specifically, these segments are (0, A], (A, B], (B, C], and (C, X], where each segment is a left-open, right-closed interval.

docs/ZH_CN/source/method_tutorials/changing_resolution.md

@@ -49,7 +49,7 @@
 }
 ```
 
-表示总步数为50，0到25步的分辨率为0.75倍原始分辨率，26到最后一步的分辨率为原始分辨率。
+表示总步数为50，1到25步的分辨率为0.75倍原始分辨率，26到最后一步的分辨率为原始分辨率。
 
 ### 举例2：
 ```
@@ -61,4 +61,8 @@
 }
 ```
 
-表示总步数为50，0到10步的分辨率为原始分辨率，11到35步的分辨率为0.75倍原始分辨率，36到最后一步的分辨率为原始分辨率。
+表示总步数为50，1到10步的分辨率为原始分辨率，11到35步的分辨率为0.75倍原始分辨率，36到最后一步的分辨率为原始分辨率。
+
+通常来说，假设`changing_resolution_steps`为[A, B, C]，去噪的起始步为1，总步数为X，则推理会被分成4个部分。
+
+分别是，(0, A], (A, B]. (B, C], (C, X]，每个部分是左开右闭集合。