diff --git a/README.md b/README.md
index fdad65d..571ac58 100644
--- a/README.md
+++ b/README.md
@@ -96,6 +96,7 @@ python auto_remove_redlight.py 01.MOV 03.MOV 05.MOV
 | `transition` | `true` | 剪接點是否加轉場（淡出淡入 + 恆定功率交叉淡化）。**開啟會強制重新編碼**，有 NVIDIA 顯卡時自動用 NVENC 加速 |
 | `transition_duration` | `0.5` | 轉場長度（秒），畫面與聲音共用以維持同步 |
 | `video_transition` | `fadeblack` | 畫面轉場類型：`fadeblack`=淡出到黑再淡入；`fade`=交叉溶接；其餘見 FFmpeg `xfade` 文件 |
+| `video_quality` | `30` | 重新編碼畫質（NVENC `-rc vbr -cq`／x264 `-crf`）。數字越大檔案越小、畫質越低。參考（4K 來源約 54Mbps）：`28`≈高畫質（檔大）／`30`≈接近原檔／`33`≈省空間／`36`≈更小 |
 | `volume_boost` | `true` | **音量增益**（Adobe PR「增益／音量」）：是否放大音量 |
 | `volume_boost_percent` | `30` | 音量增加幅度（%），`30` = 放大成 130%（×1.3 ≈ +2.3dB） |
 | `hard_limiter` | `true` | **強制壓限**（Adobe PR「強制壓限／Hard Limiter」）：拉大音量後把峰值壓在 0dB 以下，避免破音 |
diff --git a/auto_remove_redlight.py b/auto_remove_redlight.py
index 1a44e31..4378a6f 100644
--- a/auto_remove_redlight.py
+++ b/auto_remove_redlight.py
@@ -117,6 +117,10 @@ USE_GPU         = True              # EasyOCR 是否用 GPU。需 CUDA + GPU 版
                                     #   設 True 時若沒有 CUDA,EasyOCR 會自動退回 CPU(不會壞)
 REENCODE        = False             # False = 無損 -c copy(切點對齊關鍵幀,可能 ±1~2 秒)
                                     # True  = 重新編碼(切點精準到幀,但較慢、非無損)
+VIDEO_QUALITY   = 30                # 重新編碼(轉場/REENCODE)畫質。NVENC 用 -rc vbr -cq,
+                                    #   數字越大檔案越小、畫質越低。參考(4K 來源約 54Mbps):
+                                    #   28≈高畫質(~69Mbps,檔大) / 30≈接近原檔 / 33≈省空間(~37Mbps)
+                                    #   / 36≈更小。同一數字也用作 x264 -crf(CPU 退回時)。
 PROGRESS_EVERY  = 60                # 進度回報: 每處理幾秒影片印一行目前時速 (秒)。
                                     #   純顯示用,改小只是印多幾行,不影響速度與偵測精度
 
@@ -463,7 +467,7 @@ def ffmpeg_cut_concat(input_path: str, keeps: List[Tuple[float, float]],
                     "ffmpeg", "-y",
                     "-ss", f"{start:.3f}", "-i", input_path,
                     "-t", f"{dur:.3f}",
-                    "-c:v", "libx264", "-preset", "medium", "-crf", "18",
+                    "-c:v", "libx264", "-preset", "medium", "-crf", str(VIDEO_QUALITY),
                     "-c:a", "aac", "-b:a", "192k",
                     "-avoid_negative_ts", "make_zero",
                     seg,
@@ -619,11 +623,13 @@ def ffmpeg_cut_concat_xfade(input_path: str, keeps: List[Tuple[float, float]],
 
     filtergraph = ";".join(parts)
 
-    # --- 編碼器: 有 GPU 用 NVENC,否則 libx264 ---
+    # --- 編碼器: 有 GPU 用 NVENC,否則 libx264;畫質由 VIDEO_QUALITY 控制 ---
+    # NVENC 必須搭配 -rc vbr,-cq 才會真正控制位元率/檔案大小(否則位元率會爆高)
     if use_gpu:
-        venc = ["-c:v", "h264_nvenc", "-preset", "p5", "-cq", "19"]
+        venc = ["-c:v", "h264_nvenc", "-preset", "p5",
+                "-rc", "vbr", "-cq", str(VIDEO_QUALITY)]
     else:
-        venc = ["-c:v", "libx264", "-preset", "medium", "-crf", "18"]
+        venc = ["-c:v", "libx264", "-preset", "medium", "-crf", str(VIDEO_QUALITY)]
 
     cmd += ["-filter_complex", filtergraph, "-map", f"[{vlabel}]"]
     if audio:
@@ -974,6 +980,7 @@ _CONFIG_KEYS = {
     "transition":         "TRANSITION",
     "transition_duration": "TRANSITION_DURATION",
     "video_transition":   "VIDEO_TRANSITION",
+    "video_quality":      "VIDEO_QUALITY",
     "volume_boost":          "VOLUME_BOOST",
     "volume_boost_percent":  "VOLUME_BOOST_PERCENT",
     "hard_limiter":          "HARD_LIMITER",
diff --git a/config.json b/config.json
index 0e67464..9dff581 100644
--- a/config.json
+++ b/config.json
@@ -20,6 +20,7 @@
   "transition": true,
   "transition_duration": 0.5,
   "video_transition": "fadeblack",
+  "video_quality": 30,
   "volume_boost": true,
   "volume_boost_percent": 30,
   "hard_limiter": true,