fix: update document

Author: Fiona2016

flashduty/en/2. RUM/5. Session Replay/1. Overview.md

@@ -35,7 +35,7 @@ Flashduty RUM's session replay functionality is divided into two key phases: **B
 
 ### 1. Behavior Recording and Replay
 
-Quickly recording user behavior and generating replays is the first step in analysis. During the replay phase, the recording SDK takes snapshots of the current DOM and CSS styles, and collects corresponding events when user behaviors occur (DOM changes, mouse movements, clicks, form inputs, etc.). Data is reported after serialization, compression, and removal of sensitive information.
+Quickly recording user behavior and generating replays is the first step in analysis. During the recording phase, the recording SDK takes snapshots of the current DOM and CSS styles, and collects corresponding events when user behaviors occur (DOM changes, mouse movements, clicks, form inputs, etc.). Data is reported after serialization, compression, and removal of sensitive information.
 
 ### 2. Problem Analysis and Optimization
 

flashduty/en/2. RUM/5. Session Replay/2. SDK Configuration.md

@@ -27,6 +27,9 @@ window.FC_RUM.init({
 
 ::: tip
 Sampling Method: When the client SDK initializes a session, it generates a random number between 0-1 and compares it with `rate/100`. If it falls within the range, that session will be collected as a sample, and replay data will be collected and reported within the session cycle.
+
+Based on sampled session, the session will be
+Based on the session being sampled, the session replay sampling rate (`sessionReplaySampleRate`) will be applied for a second round of calculation and sampling.
 :::
 
 By default, after configuring the sampling rate, automatic collection will be enabled after `RUM.init()` is executed. If you want to manually control the collection timing (such as collecting data after user login), you can first enable the manual collection switch, then manually call the record method.

flashduty/zh/2. RUM/5.会话重放/1. 概览.md

@@ -35,7 +35,7 @@ Flashduty RUM 的会话重放功能分为两个关键阶段：**行为记录与
 
 ### 1. 行为记录与回放
 
-快速记录用户行为并生成回放是分析的第一步。在回放阶段，录制 SDK 会将当前 dom 和 css 样式打快照，并在用户行为（DOM 变化、鼠标移动、点击、表单输入等）发生时收集对应的事件。通过序列化、压缩、去除敏感信息后进行数据上报。
+快速记录用户行为并生成回放是分析的第一步。在录制阶段，录制 SDK 会将当前 dom 和 css 样式打快照，并在用户行为（DOM 变化、鼠标移动、点击、表单输入等）发生时收集对应的事件。通过序列化、压缩、去除敏感信息后进行数据上报。
 
 ### 2. 问题分析与优化
 

flashduty/zh/2. RUM/5.会话重放/2. SDK 配置.md

@@ -26,7 +26,10 @@ window.FC_RUM.init({
 ```
 
 ::: tip
+
 采样方式：在客户端 sdk 初始化 session 时生成 0-1 之间的随机数，与 `rate/100` 进行大小比较。如落在区间内，则该 session 会作为采集样本，回放数据会在 session 周期内采集与上报。
+
+在 session 被采样的基础上，会话重放的采样率(sessionReplaySampleRate)会被进行二次计算和采样。
 :::
 
 默认配置采样率后，会在`RUM.init()`执行后开启自动采集。若想手动控制采集时机（如用户登录后再进行数据采集），可先开启手动采集开关，再手动调用 record 方法。