diff --git a/handlers/render_video.py b/handlers/render_video.py
index 2369522..638b932 100644
--- a/handlers/render_video.py
+++ b/handlers/render_video.py
@@ -275,12 +275,24 @@ class RenderSegmentVideoHandler(BaseHandler):
 
         cmd.extend(['-vf', ','.join(filters)])
 
+        # 计算总帧数，动态调整 GOP
+        total_frames = int(actual_duration_sec * fps)
+        if total_frames <= 1:
+            gop_size = 1
+        elif total_frames < fps:
+            gop_size = total_frames
+        else:
+            gop_size = fps * 2  # 正常情况，2 秒一个关键帧
+
         # 编码参数
         cmd.extend([
             '-c:v', 'libx264',
             '-preset', 'fast',
             '-crf', '18',
             '-r', str(fps),
+            '-g', str(gop_size),
+            '-keyint_min', str(min(gop_size, fps // 2 or 1)),
+            '-force_key_frames', 'expr:eq(n,0)',
             '-an',  # 无音频
             output_file
         ])
@@ -357,16 +369,28 @@ class RenderSegmentVideoHandler(BaseHandler):
         fps = output_spec.fps
         cmd.extend(['-r', str(fps)])
 
-        # GOP 大小（关键帧间隔）
-        gop_size = fps * 2  # 2秒一个关键帧
-        cmd.extend(['-g', str(gop_size)])
-        cmd.extend(['-keyint_min', str(gop_size)])
-
         # 时长（包含 overlap 区域）
         total_duration_ms = duration_ms + overlap_head_ms + overlap_tail_ms
         duration_sec = total_duration_ms / 1000.0
         cmd.extend(['-t', str(duration_sec)])
 
+        # 动态调整 GOP 大小：对于短视频，GOP 不能大于总帧数
+        total_frames = int(duration_sec * fps)
+        if total_frames <= 1:
+            gop_size = 1
+        elif total_frames < fps:
+            # 短于 1 秒的视频，使用全部帧数作为 GOP（整个视频只有开头一个关键帧）
+            gop_size = total_frames
+        else:
+            # 正常情况，2 秒一个关键帧
+            gop_size = fps * 2
+
+        cmd.extend(['-g', str(gop_size)])
+        cmd.extend(['-keyint_min', str(min(gop_size, fps // 2 or 1))])
+
+        # 强制第一帧为关键帧
+        cmd.extend(['-force_key_frames', 'expr:eq(n,0)'])
+
         # 无音频（视频片段不包含音频）
         cmd.append('-an')