diff --git a/src/record_manager.cpp b/src/record_manager.cpp
index 00cf990..8ae8eda 100644
--- a/src/record_manager.cpp
+++ b/src/record_manager.cpp
@@ -322,20 +322,63 @@ std::vector<RecordSegment> RecordManager::querySegments(const std::string& strea
 //
 RecordSegment RecordManager::getSegment(const std::string& segmentId)
 {
-    auto pos1 = segmentId.find('_');
-    auto pos2 = segmentId.find('_', pos1 + 1);
-    if (pos1 == std::string::npos || pos2 == std::string::npos) return {};
+    // 1) 找最后一个 "_"
+    size_t pos_last = segmentId.rfind('_');
+    if (pos_last == std::string::npos) return {};
 
-    std::string stream = segmentId.substr(0, pos1);
-    int64_t start_ms = std::stoll(segmentId.substr(pos1 + 1, pos2 - pos1 - 1));
-    int64_t end_ms = std::stoll(segmentId.substr(pos2 + 1));
+    // 2) 再往前找一个 "_"
+    size_t pos_mid = segmentId.rfind('_', pos_last - 1);
+    if (pos_mid == std::string::npos) return {};
 
-    auto segs = querySegments(stream, start_ms, end_ms);
-    for (auto& s : segs)
+    // 3) 三段拆分
+    std::string stream = segmentId.substr(0, pos_mid);
+    std::string startStr = segmentId.substr(pos_mid + 1, pos_last - pos_mid - 1);
+    std::string endStr = segmentId.substr(pos_last + 1);
+
+    int64_t start_ms = 0;
+    int64_t end_ms = 0;
+
+    try
     {
-        if (s.start_ms == start_ms && s.end_ms == end_ms) return s;
+        start_ms = std::stoll(startStr);
+        end_ms = std::stoll(endStr);
     }
-    return {};
+    catch (...)
+    {
+        LOG_ERROR("[RecordManager] segmentId parse failed: " + segmentId);
+        return {};
+    }
+
+    // 确认 stream 在 index_ 里
+    if (!index_.count(stream))
+    {
+        LOG_WARN("[RecordManager] stream not exist in index: " + stream);
+        return {};
+    }
+
+    // 4) 根据时间区间收集属于该 segment 的所有文件
+    const auto& files = index_[stream];
+
+    RecordSegment seg;
+    seg.segment_id = segmentId;
+    seg.index = 1;
+    seg.start_ms = start_ms;
+    seg.end_ms = end_ms;
+
+    for (const auto& f : files)
+    {
+        // 与 segment 时间区间有重叠的文件都属于这个 segment
+        bool overlap = !(f.end_ms <= start_ms || f.start_ms >= end_ms);
+        if (overlap) seg.files.push_back(f);
+    }
+
+    if (seg.files.empty())
+    {
+        LOG_WARN("[RecordManager] No files found for segmentId: " + segmentId);
+        return {};
+    }
+
+    return seg;
 }
 
 int64_t RecordManager::toMsTimestamp(const std::string& s)