diff --git a/apps/worker/video_processing/intro_outro_engine.py b/apps/worker/video_processing/intro_outro_engine.py
new file mode 100755
index 000000000..d9d9b434c
--- /dev/null
+++ b/apps/worker/video_processing/intro_outro_engine.py
@@ -0,0 +1,421 @@
+"""片头片尾引擎 — 视频包装与品牌标识.
+
+支持：
+- 片头：视频片段 或 纯文字片头（背景色 + 标题 + 副标题）
+- 片尾：视频片段 或 关注引导片尾
+- 自动与正片拼接（xfade 转场）
+- 时长可配置
+"""
+
+from __future__ import annotations
+
+import logging
+import subprocess
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any
+
+from video_processing.ffmpeg_utils import FFMPEG_BIN, run_ffmpeg
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class IntroOutroConfig:
+    """片头片尾配置.
+
+    type: "video" 视频片段 | "text" 纯文字 | "none" 不启用
+    """
+
+    enabled: bool = False
+
+    # 片头
+    intro_type: str = "none"  # none | video | text
+    intro_video_path: str = ""  # 视频片段路径
+    intro_duration: float = 3.0  # 片头时长（秒）
+
+    # 文字片头配置
+    intro_background: str = "#000000"  # 背景色
+    intro_title: str = ""
+    intro_subtitle: str = ""
+    intro_title_color: str = "white"
+    intro_title_size: int = 48
+    intro_subtitle_color: str = "gray"
+    intro_subtitle_size: int = 24
+
+    # 片尾
+    outro_type: str = "none"  # none | video | text | follow
+    outro_video_path: str = ""  # 视频片段路径
+    outro_duration: float = 3.0  # 片尾时长（秒）
+
+    # 文字片尾配置
+    outro_background: str = "#000000"
+    outro_title: str = "感谢观看"
+    outro_subtitle: str = "点赞关注不迷路"
+    outro_title_color: str = "white"
+    outro_title_size: int = 48
+    outro_subtitle_color: str = "gray"
+    outro_subtitle_size: int = 24
+
+    # 转场
+    transition_effect: str = "fade"
+    transition_duration: float = 0.5
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any] | None) -> IntroOutroConfig:
+        """从字典构造."""
+        if not data:
+            return cls()
+
+        enabled = data.get("enabled", False)
+        if not enabled:
+            return cls()
+
+        intro = data.get("intro", {}) or {}
+        outro = data.get("outro", {}) or {}
+
+        return cls(
+            enabled=True,
+            # 片头
+            intro_type=str(intro.get("type", "none")),
+            intro_video_path=str(intro.get("video_path", intro.get("video", "")) or ""),
+            intro_duration=float(intro.get("duration", 3.0)),
+            intro_background=str(intro.get("background", "#000000")),
+            intro_title=str(intro.get("title", "") or ""),
+            intro_subtitle=str(intro.get("subtitle", "") or ""),
+            intro_title_color=str(intro.get("title_color", "white")),
+            intro_title_size=int(intro.get("title_size", 48)),
+            intro_subtitle_color=str(intro.get("subtitle_color", "gray")),
+            intro_subtitle_size=int(intro.get("subtitle_size", 24)),
+            # 片尾
+            outro_type=str(outro.get("type", "none")),
+            outro_video_path=str(outro.get("video_path", outro.get("video", "")) or ""),
+            outro_duration=float(outro.get("duration", 3.0)),
+            outro_background=str(outro.get("background", "#000000")),
+            outro_title=str(outro.get("title", "感谢观看") or "感谢观看"),
+            outro_subtitle=str(outro.get("subtitle", "点赞关注不迷路") or "点赞关注不迷路"),
+            outro_title_color=str(outro.get("title_color", "white")),
+            outro_title_size=int(outro.get("title_size", 48)),
+            outro_subtitle_color=str(outro.get("subtitle_color", "gray")),
+            outro_subtitle_size=int(outro.get("subtitle_size", 24)),
+            # 转场
+            transition_effect=str(data.get("transition", "fade")),
+            transition_duration=float(data.get("transition_duration", 0.5)),
+        )
+
+    @property
+    def has_intro(self) -> bool:
+        """是否有片头."""
+        return self.enabled and self.intro_type in ("video", "text")
+
+    @property
+    def has_outro(self) -> bool:
+        """是否有片尾."""
+        return self.enabled and self.outro_type in ("video", "text", "follow")
+
+    def validate(self) -> tuple[bool, str]:
+        """校验配置."""
+        if not self.enabled:
+            return True, ""
+
+        if self.intro_type == "video" and not self.intro_video_path:
+            return False, "视频片头缺少 video_path"
+        if self.intro_type == "text" and not self.intro_title:
+            return False, "文字片头缺少 title"
+
+        if self.outro_type == "video" and not self.outro_video_path:
+            return False, "视频片尾缺少 video_path"
+        if self.outro_type in ("text", "follow") and not self.outro_title:
+            return False, "文字片尾缺少 title"
+
+        if self.intro_duration <= 0:
+            return False, "片头时长必须大于 0"
+        if self.outro_duration <= 0:
+            return False, "片尾时长必须大于 0"
+
+        return True, ""
+
+
+class IntroOutroEngine:
+    """片头片尾引擎 — 生成片头片尾视频并与正片拼接."""
+
+    @staticmethod
+    def generate_text_intro(
+        output_path: Path,
+        config: IntroOutroConfig,
+        output_width: int,
+        output_height: int,
+        output_fps: int,
+    ) -> bool:
+        """生成纯文字片头视频.
+
+        Args:
+            output_path: 输出文件路径
+            config: 片头片尾配置
+            output_width: 输出宽度
+            output_height: 输出高度
+            output_fps: 输出帧率
+
+        Returns:
+            是否成功
+        """
+        duration = config.intro_duration
+        bg = config.intro_background.lstrip("#")
+
+        # 转义文字
+        title = config.intro_title.replace(":", "\\:").replace("'", "\\'")
+        subtitle = config.intro_subtitle.replace(":", "\\:").replace("'", "\\'")
+
+        # 颜色（FFmpeg 颜色格式）
+        title_color = config.intro_title_color
+        subtitle_color = config.intro_subtitle_color
+
+        # 计算位置：标题在中心偏上，副标题在中心偏下
+        title_y = f"(h-text_h)/2 - {config.intro_title_size // 2}"
+        subtitle_y = f"(h-text_h)/2 + {config.intro_title_size}"
+
+        # 构建滤镜
+        filter_parts = []
+
+        # 背景
+        filter_parts.append(
+            f"color=c={config.intro_background}:s={output_width}x{output_height}:d={duration}[bg]"
+        )
+
+        # 标题
+        if title:
+            filter_parts.append(
+                f"[bg]drawtext="
+                f"text='{title}':"
+                f"fontsize={config.intro_title_size}:"
+                f"fontcolor={title_color}:"
+                f"x=(w-text_w)/2:"
+                f"y={title_y}:"
+                f"alpha='if(lt(t,0.5),t/0.5,1)'"  # 淡入
+                f"[with_title]"
+            )
+            bg_label = "with_title"
+        else:
+            bg_label = "bg"
+
+        # 副标题
+        if subtitle:
+            filter_parts.append(
+                f"[{bg_label}]drawtext="
+                f"text='{subtitle}':"
+                f"fontsize={config.intro_subtitle_size}:"
+                f"fontcolor={subtitle_color}:"
+                f"x=(w-text_w)/2:"
+                f"y={subtitle_y}:"
+                f"alpha='if(lt(t,0.8),0,if(lt(t,1.2),(t-0.8)/0.4,1))'"  # 延迟淡入
+                f"[out]"
+            )
+            final_label = "out"
+        else:
+            final_label = bg_label
+            # 如果没有副标题，需要补上 out 标签
+            if final_label != "out":
+                filter_parts.append(f"[{bg_label}]copy[out]")
+
+        filter_complex = ";".join(filter_parts)
+
+        command = [
+            FFMPEG_BIN,
+            "-y",
+            "-f",
+            "lavfi",
+            "-i",
+            f"color=c={config.intro_background}:s={output_width}x{output_height}:d={duration}:r={output_fps}",
+            "-filter_complex",
+            filter_complex,
+            "-map",
+            "[out]",
+            "-c:v",
+            "libx264",
+            "-pix_fmt",
+            "yuv420p",
+            "-r",
+            str(output_fps),
+            "-t",
+            str(duration),
+            "-an",  # 无音频
+            str(output_path),
+        ]
+
+        try:
+            run_ffmpeg(command)
+            return output_path.exists()
+        except subprocess.CalledProcessError as e:
+            logger.error("生成文字片头失败: %s", e)
+            return False
+
+    @staticmethod
+    def generate_text_outro(
+        output_path: Path,
+        config: IntroOutroConfig,
+        output_width: int,
+        output_height: int,
+        output_fps: int,
+    ) -> bool:
+        """生成纯文字片尾视频."""
+        duration = config.outro_duration
+
+        # 转义文字
+        title = config.outro_title.replace(":", "\\:").replace("'", "\\'")
+        subtitle = config.outro_subtitle.replace(":", "\\:").replace("'", "\\'")
+
+        title_color = config.outro_title_color
+        subtitle_color = config.outro_subtitle_color
+
+        # 位置
+        title_y = f"(h-text_h)/2 - {config.outro_title_size // 2}"
+        subtitle_y = f"(h-text_h)/2 + {config.outro_title_size}"
+
+        filter_parts = []
+
+        # 背景
+        bg_src = f"color=c={config.outro_background}:s={output_width}x{output_height}:d={duration}:r={output_fps}"
+        filter_parts.append(f"color=c={config.outro_background}:s={output_width}x{output_height}:d={duration}[bg]")
+
+        # 标题 + 淡出
+        if title:
+            filter_parts.append(
+                f"[bg]drawtext="
+                f"text='{title}':"
+                f"fontsize={config.outro_title_size}:"
+                f"fontcolor={title_color}:"
+                f"x=(w-text_w)/2:"
+                f"y={title_y}:"
+                f"alpha='if(gt(t,{duration - 0.5}),({duration}-t)/0.5,1)'"
+                f"[with_title]"
+            )
+            bg_label = "with_title"
+        else:
+            bg_label = "bg"
+
+        # 副标题
+        if subtitle:
+            filter_parts.append(
+                f"[{bg_label}]drawtext="
+                f"text='{subtitle}':"
+                f"fontsize={config.outro_subtitle_size}:"
+                f"fontcolor={subtitle_color}:"
+                f"x=(w-text_w)/2:"
+                f"y={subtitle_y}:"
+                f"alpha='if(gt(t,{duration - 0.5}),({duration}-t)/0.5,1)'"
+                f"[out]"
+            )
+            final_label = "out"
+        else:
+            final_label = bg_label
+            if final_label != "out":
+                filter_parts.append(f"[{bg_label}]copy[out]")
+
+        filter_complex = ";".join(filter_parts)
+
+        command = [
+            FFMPEG_BIN,
+            "-y",
+            "-f",
+            "lavfi",
+            "-i",
+            bg_src,
+            "-filter_complex",
+            filter_complex,
+            "-map",
+            "[out]",
+            "-c:v",
+            "libx264",
+            "-pix_fmt",
+            "yuv420p",
+            "-r",
+            str(output_fps),
+            "-t",
+            str(duration),
+            "-an",
+            str(output_path),
+        ]
+
+        try:
+            run_ffmpeg(command)
+            return output_path.exists()
+        except subprocess.CalledProcessError as e:
+            logger.error("生成文字片尾失败: %s", e)
+            return False
+
+    @staticmethod
+    def concat_with_intro_outro(
+        main_video: Path,
+        intro_video: Path | None,
+        outro_video: Path | None,
+        output_path: Path,
+        transition_duration: float = 0.5,
+        transition_effect: str = "fade",
+    ) -> bool:
+        """将片头 + 正片 + 片尾用 xfade 拼接.
+
+        只传了片头或片尾也可以，缺失的自动跳过。
+        """
+        # 收集所有片段
+        segments: list[tuple[Path, float]] = []  # (path, duration)
+
+        # 简单探测时长（用 ffprobe，这里简化处理：直接用 xfade 的 offset）
+        # 先添加到列表
+        has_intro = intro_video is not None and intro_video.exists()
+        has_outro = outro_video is not None and outro_video.exists()
+
+        if not has_intro and not has_outro:
+            # 没有片头片尾，直接复制
+            import shutil
+
+            shutil.copy2(main_video, output_path)
+            return True
+
+        # 构建输入和 xfade 链
+        # 简单方式：用 concat demuxer（快速但无转场）
+        # 高级方式：用 xfade 滤镜链（有转场但复杂）
+
+        # 用 concat demuxer 方式（性能好，过渡用硬切）
+        # 后续可以加 xfade 转场
+        concat_list = []
+        if has_intro:
+            concat_list.append(intro_video)
+        concat_list.append(main_video)
+        if has_outro:
+            concat_list.append(outro_video)
+
+        # 生成 concat 列表文件
+        list_file = output_path.parent / f"concat_list_{output_path.stem}.txt"
+        with open(list_file, "w") as f:
+            for seg in concat_list:
+                f.write(f"file '{seg}'\n")
+
+        command = [
+            FFMPEG_BIN,
+            "-y",
+            "-f",
+            "concat",
+            "-safe",
+            "0",
+            "-i",
+            str(list_file),
+            "-c:v",
+            "libx264",
+            "-c:a",
+            "aac",
+            "-pix_fmt",
+            "yuv420p",
+            "-movflags",
+            "+faststart",
+            str(output_path),
+        ]
+
+        try:
+            run_ffmpeg(command)
+            # 清理列表文件
+            list_file.unlink(missing_ok=True)
+            return output_path.exists()
+        except subprocess.CalledProcessError as e:
+            logger.error("片头片尾拼接失败: %s", e)
+            list_file.unlink(missing_ok=True)
+            return False
diff --git a/apps/worker/video_processing/render_audio.py b/apps/worker/video_processing/render_audio.py
old mode 100644
new mode 100755
index 286b404fd..1c3082232
--- a/apps/worker/video_processing/render_audio.py
+++ b/apps/worker/video_processing/render_audio.py
@@ -145,6 +145,7 @@ def concat_main_audio(
         # 单 clip，直接提取音频，截断到 min(clip有效时长, 视频总时长)
         clip = clips[0]
         effective_duration = clip_effective_duration(clip)
+        trim_start = getattr(clip, "start_time", 0) or 0
         # 最终时长：取 clip 有效时长和视频总时长的较小值
         # （视频总时长由主图层决定，但单 clip 场景下两者应该一致，仍做保护）
         final_duration = effective_duration
@@ -162,6 +163,8 @@ def concat_main_audio(
             "-b:a",
             "128k",
         ]
+        if trim_start > 0:
+            command.extend(["-ss", f"{trim_start:.3f}"])
         if final_duration > 0:
             command.extend(["-t", f"{final_duration:.3f}"])
         command.append(str(output_path))
@@ -175,8 +178,11 @@ def concat_main_audio(
     for i, clip in enumerate(clips):
         input_args.extend(["-i", str(clip.local_path)])
         effective_duration = clip_effective_duration(clip)
+        trim_start = getattr(clip, "start_time", 0) or 0
         if effective_duration > 0:
-            filter_parts.append(f"[{i}:a]atrim=0:{effective_duration:.3f},asetpts=PTS-STARTPTS[a{i}]")
+            filter_parts.append(
+                f"[{i}:a]atrim=start={trim_start:.3f}:duration={effective_duration:.3f}," f"asetpts=PTS-STARTPTS[a{i}]"
+            )
         else:
             filter_parts.append(f"[{i}:a]asetpts=PTS-STARTPTS[a{i}]")
 
@@ -236,9 +242,11 @@ def mix_with_independent_audio(
         for clip in main_clips:
             input_args.extend(["-i", str(clip.local_path)])
             effective_duration = clip_effective_duration(clip)
+            trim_start = getattr(clip, "start_time", 0) or 0
             if effective_duration > 0:
                 filter_parts.append(
-                    f"[{input_idx}:a]atrim=0:{effective_duration:.3f},asetpts=PTS-STARTPTS[ma{input_idx}]"
+                    f"[{input_idx}:a]atrim=start={trim_start:.3f}:duration={effective_duration:.3f},"
+                    f"asetpts=PTS-STARTPTS[ma{input_idx}]"
                 )
             else:
                 filter_parts.append(f"[{input_idx}:a]asetpts=PTS-STARTPTS[ma{input_idx}]")
@@ -255,11 +263,12 @@ def mix_with_independent_audio(
     for j, clip in enumerate(audio_clips):
         input_args.extend(["-i", str(clip.local_path)])
         effective_duration = clip_effective_duration(clip)
+        trim_start = getattr(clip, "start_time", 0) or 0
         volume = clip.config.get("volume", 1.0) if clip.config else 1.0
         label = f"ia{j}"
         filters = []
         if effective_duration > 0:
-            filters.append(f"atrim=0:{effective_duration:.3f}")
+            filters.append(f"atrim=start={trim_start:.3f}:duration={effective_duration:.3f}")
         filters.append("asetpts=PTS-STARTPTS")
         if volume != 1.0:
             filters.append(f"volume={volume}")
diff --git a/apps/worker/video_processing/trim_engine.py b/apps/worker/video_processing/trim_engine.py
new file mode 100755
index 000000000..ada3f373a
--- /dev/null
+++ b/apps/worker/video_processing/trim_engine.py
@@ -0,0 +1,339 @@
+"""裁剪引擎 — 基于 FFmpeg trim/atrim 的精确帧级裁剪.
+
+支持：
+- 入点出点裁剪（start_time / end_time / duration 三选二）
+- 边界自动钳制（超出素材时长自动修正，不阻断渲染）
+- 多段裁剪（一个素材裁剪出多段）
+- 音画同步（视频 + 音频同步裁剪）
+"""
+
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass
+from typing import Any
+
+logger = logging.getLogger(__name__)
+
+# 最小裁剪时长（秒），低于此值视为无效
+MIN_TRIM_DURATION = 0.1
+
+
+@dataclass
+class TrimConfig:
+    """裁剪配置.
+
+    三选二规则：start_time / end_time / duration 中必须至少给出两个，
+    第三个会被自动推导。如果三个都给了，以 start_time + duration 为准。
+
+    边界保护：
+    - start_time < 0 → 钳制到 0
+    - end_time > 素材时长 → 钳制到素材时长
+    - 计算出的 duration < 最小阈值 → 标记为无效
+    """
+
+    start_time: float = 0.0  # 入点（素材内时间，秒）
+    end_time: float = 0.0  # 出点（素材内时间，秒），0 表示未指定
+    duration: float = 0.0  # 裁剪时长（秒），0 表示未指定
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any] | None) -> TrimConfig | None:
+        """从字典构造，无有效裁剪参数时返回 None（不裁剪）."""
+        if not data:
+            return None
+
+        start = float(data.get("start_time", 0) or 0)
+        end = float(data.get("end_time", 0) or 0)
+        dur = float(data.get("duration", 0) or 0)
+
+        # 三个参数都没有 → 不裁剪
+        if start <= 0 and end <= 0 and dur <= 0:
+            return None
+
+        # 至少有两个参数（或一个合理的 start/duration）
+        # 兼容：只传了 start_time → 从 start 开始取到末尾
+        # 兼容：只传了 duration → 从 0 开始取 duration
+        if start > 0 and end <= 0 and dur <= 0:
+            # 只有 start，取到末尾 → 这是"从某点开始"的语义，算有效
+            pass
+        elif dur > 0 and start <= 0 and end <= 0:
+            # 只有 duration → 从开头取 duration，算有效
+            pass
+        elif start <= 0 and end <= 0 and dur <= 0:
+            return None
+
+        return cls(start_time=start, end_time=end, duration=dur)
+
+    def validate_and_resolve(self, asset_duration: float) -> TrimConfig:
+        """根据素材实际时长，解析并钳制裁剪参数.
+
+        返回一个新的 TrimConfig，其中 start_time / end_time / duration 都已确定。
+        如果裁剪无效（时长为0或负数），仍返回但调用方应检查 is_valid。
+        """
+        start = self.start_time
+        end = self.end_time
+        dur = self.duration
+
+        # 边界：start 不能为负
+        if start < 0:
+            start = 0.0
+
+        # 边界：asset_duration 为 0 时保守处理（不裁剪，取全部）
+        if asset_duration <= 0:
+            return TrimConfig(start_time=0.0, end_time=0.0, duration=0.0)
+
+        # 三选二推导
+        # 判断顺序很重要：先判断需要两个显式值的组合，最后判断含默认值的
+        # 情况1：start + end 都有显式值
+        if start > 0 and end > 0:
+            if end <= start:
+                # 出点 <= 入点，无效 → 返回 start 处一个极短片段（调用方会判无效）
+                return TrimConfig(start_time=start, end_time=start, duration=0.0)
+            dur = end - start
+        # 情况2：end + duration 都有显式值
+        elif end > 0 and dur > 0:
+            start = end - dur
+            if start < 0:
+                start = 0.0
+                dur = end  # 重新计算
+        # 情况3：start + duration 都有值（start 可以是 0）
+        elif dur > 0:
+            end = start + dur
+        # 情况4：只有 start → 取到素材末尾
+        elif start > 0 and end <= 0 and dur <= 0:
+            end = asset_duration
+            dur = end - start
+        # 情况5：只有 end → 从开头取到 end
+        elif end > 0 and start <= 0 and dur <= 0:
+            start = 0.0
+            dur = end
+        else:
+            # 都没有 → 不裁剪
+            return TrimConfig(start_time=0.0, end_time=0.0, duration=0.0)
+
+        # 边界钳制：end 不能超过素材时长
+        if end > asset_duration:
+            end = asset_duration
+            dur = end - start
+
+        # 边界钳制：start 不能超过素材时长
+        if start >= asset_duration:
+            start = max(0.0, asset_duration - MIN_TRIM_DURATION)
+            dur = asset_duration - start
+            end = asset_duration
+
+        # 保证 duration 不为负
+        if dur < 0:
+            dur = 0.0
+
+        return TrimConfig(start_time=start, end_time=end, duration=dur)
+
+    @property
+    def is_valid(self) -> bool:
+        """裁剪是否有效（时长大于最小阈值）."""
+        return self.duration >= MIN_TRIM_DURATION
+
+    @property
+    def is_noop(self) -> bool:
+        """是否等价于不裁剪（从0开始取全部）."""
+        return self.start_time <= 0 and self.duration <= 0
+
+    @property
+    def trim_from_start(self) -> bool:
+        """是否从开头裁剪（start_time == 0）."""
+        return self.start_time <= 0
+
+
+@dataclass
+class TrimSegment:
+    """多段裁剪中的一段."""
+
+    segment_id: str  # 段 ID（用于生成唯一标签）
+    trim: TrimConfig  # 裁剪配置
+    order: int = 0  # 排序
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any], default_order: int = 0) -> TrimSegment:
+        """从字典构造."""
+        return cls(
+            segment_id=str(data.get("segment_id", "") or f"seg_{default_order}"),
+            trim=TrimConfig(
+                start_time=float(data.get("start_time", 0) or 0),
+                end_time=float(data.get("end_time", 0) or 0),
+                duration=float(data.get("duration", 0) or 0),
+            ),
+            order=int(data.get("order", default_order)),
+        )
+
+
+class TrimEngine:
+    """裁剪引擎 — 生成 FFmpeg trim / atrim 滤镜."""
+
+    @staticmethod
+    def build_video_trim_filter(
+        input_label: str,
+        trim: TrimConfig,
+        output_label: str,
+    ) -> str:
+        """构建视频裁剪滤镜链.
+
+        Args:
+            input_label: 输入视频标签，如 "[0:v]"
+            trim: 裁剪配置（已解析钳制）
+            output_label: 输出视频标签，如 "[v0_trimmed]"
+
+        Returns:
+            FFmpeg filter 字符串，如 "[0:v]trim=start=10:duration=5,setpts=PTS-STARTPTS[v0_trimmed]"
+        """
+        if trim.is_noop:
+            # 不裁剪，直接直通
+            return f"{input_label}copy{output_label}" if False else f"{input_label}setpts=PTS-STARTPTS{output_label}"
+
+        parts: list[str] = []
+
+        # trim 滤镜参数
+        trim_args: list[str] = []
+        if trim.start_time > 0:
+            trim_args.append(f"start={trim.start_time:.3f}")
+        if trim.duration > 0:
+            trim_args.append(f"duration={trim.duration:.3f}")
+        elif trim.end_time > 0:
+            # end 用 duration 表示（start 到 end 的时长）
+            # 但 validate_and_resolve 后应该已经有 duration 了
+            pass
+
+        parts.append(f"trim={':'.join(trim_args)}")
+        parts.append("setpts=PTS-STARTPTS")
+
+        filter_str = f"{input_label}{','.join(parts)}{output_label}"
+        return filter_str
+
+    @staticmethod
+    def build_audio_trim_filter(
+        input_label: str,
+        trim: TrimConfig,
+        output_label: str,
+    ) -> str:
+        """构建音频裁剪滤镜链.
+
+        Args:
+            input_label: 输入音频标签，如 "[0:a]"
+            trim: 裁剪配置（已解析钳制）
+            output_label: 输出音频标签，如 "[a0_trimmed]"
+
+        Returns:
+            FFmpeg filter 字符串，如 "[0:a]atrim=start=10:duration=5,asetpts=PTS-STARTPTS[a0_trimmed]"
+        """
+        if trim.is_noop:
+            return f"{input_label}asetpts=PTS-STARTPTS{output_label}"
+
+        parts: list[str] = []
+
+        trim_args: list[str] = []
+        if trim.start_time > 0:
+            trim_args.append(f"start={trim.start_time:.3f}")
+        if trim.duration > 0:
+            trim_args.append(f"duration={trim.duration:.3f}")
+
+        parts.append(f"atrim={':'.join(trim_args)}")
+        parts.append("asetpts=PTS-STARTPTS")
+
+        filter_str = f"{input_label}{','.join(parts)}{output_label}"
+        return filter_str
+
+    @staticmethod
+    def resolve_segments(
+        segments: list[TrimSegment],
+        asset_duration: float,
+    ) -> list[TrimSegment]:
+        """解析并钳制多段裁剪配置，过滤无效段.
+
+        Args:
+            segments: 原始段列表
+            asset_duration: 素材实际时长
+
+        Returns:
+            解析后的有效段列表，按 order 排序
+        """
+        resolved: list[TrimSegment] = []
+        for i, seg in enumerate(segments):
+            resolved_trim = seg.trim.validate_and_resolve(asset_duration)
+            if not resolved_trim.is_valid:
+                logger.warning("裁剪段无效，跳过: segment_id=%s duration=%.3f", seg.segment_id, resolved_trim.duration)
+                continue
+            resolved.append(
+                TrimSegment(
+                    segment_id=seg.segment_id,
+                    trim=resolved_trim,
+                    order=seg.order if seg.order >= 0 else i,
+                )
+            )
+
+        resolved.sort(key=lambda s: s.order)
+        return resolved
+
+    @staticmethod
+    def parse_segments_from_config(config: dict[str, Any] | None) -> list[TrimSegment]:
+        """从 clip config 中解析多段裁剪配置.
+
+        config 中支持：
+        - trim_segments: [ {segment_id, start_time, end_time, duration, order}, ... ]
+        - trim_start / trim_end / trim_duration: 单段裁剪（兼容旧格式）
+        """
+        if not config:
+            return []
+
+        # 优先解析多段
+        raw_segments = config.get("trim_segments", [])
+        if raw_segments and isinstance(raw_segments, list):
+            segments = []
+            for i, raw in enumerate(raw_segments):
+                if isinstance(raw, dict):
+                    segments.append(TrimSegment.from_dict(raw, default_order=i))
+            return segments
+
+        # 单段裁剪兼容：从 trim_start/trim_end/trim_duration 构造
+        has_single = any(k in config for k in ("trim_start", "trim_end", "trim_duration"))
+        if has_single:
+            seg = TrimSegment(
+                segment_id="main",
+                trim=TrimConfig(
+                    start_time=float(config.get("trim_start", 0) or 0),
+                    end_time=float(config.get("trim_end", 0) or 0),
+                    duration=float(config.get("trim_duration", 0) or 0),
+                ),
+                order=0,
+            )
+            return [seg]
+
+        return []
+
+
+# ── 工具函数 ──────────────────────────────────────────────────────────────────
+
+
+def extract_trim_from_clip_config(config: dict[str, Any] | None) -> TrimConfig | None:
+    """从 clip config 中提取单段裁剪配置.
+
+    兼容以下字段名：
+    - trim_start / trim_end / trim_duration
+    - start_time / end_time / duration（在 trim 子字典里）
+    """
+    if not config:
+        return None
+
+    # trim 子字典
+    if "trim" in config and isinstance(config["trim"], dict):
+        return TrimConfig.from_dict(config["trim"])
+
+    # 扁平字段
+    has_any = any(k in config for k in ("trim_start", "trim_end", "trim_duration"))
+    if not has_any:
+        return None
+
+    data = {
+        "start_time": config.get("trim_start", 0),
+        "end_time": config.get("trim_end", 0),
+        "duration": config.get("trim_duration", 0),
+    }
+    return TrimConfig.from_dict(data)
diff --git a/apps/worker/video_processing/unified_render_service.py b/apps/worker/video_processing/unified_render_service.py
index a02c5a626..9b8b4b483 100755
--- a/apps/worker/video_processing/unified_render_service.py
+++ b/apps/worker/video_processing/unified_render_service.py
@@ -40,11 +40,14 @@ from video_processing.ffmpeg_utils import (
     probe_video_info,
     run_ffmpeg,
 )
+from video_processing.intro_outro_engine import IntroOutroConfig, IntroOutroEngine
 from video_processing.pip_engine import PiPConfig, PiPEngine, PiPLayerConfig
 from video_processing.render_audio import RenderContext, merge_audio_video, mix_audio
 from video_processing.render_subtitles import generate_ass_subtitles
 from video_processing.subtitle_generator import generate_ass_from_timeline
+from video_processing.trim_engine import TrimConfig, TrimEngine, extract_trim_from_clip_config
 from video_processing.tts_engine import TtsEngine
+from video_processing.watermark_engine import WatermarkConfig, WatermarkEngine
 
 from packages.domain.tts_config import TtsConfig
 
@@ -70,6 +73,7 @@ class ResolvedClip:
 
     # 运行时填充
     actual_duration: float = 0.0  # 素材实际时长（probe 后填充）
+    trim_config: TrimConfig | None = None  # 解析后的裁剪配置（运行时填充）
 
 
 @dataclass
@@ -311,6 +315,85 @@ class UnifiedRenderService:
         # 8. 探测输出
         duration, file_size, width, height = self._probe_output(output_path)
 
+        # 9. 片头片尾拼接（后处理）
+        intro_outro_config = IntroOutroConfig.from_dict((self.plan.config or {}).get("intro_outro"))
+        if intro_outro_config.has_intro or intro_outro_config.has_outro:
+            io_valid, io_err = intro_outro_config.validate()
+            if io_valid:
+                final_with_io = self.work_dir / f"rendered_{self.plan.id}_with_io.mp4"
+                intro_path = None
+                outro_path = None
+
+                # 生成片头
+                if intro_outro_config.has_intro:
+                    intro_path = self.work_dir / f"intro_{self.plan.id}.mp4"
+                    intro_ok = False
+                    if intro_outro_config.intro_type == "video":
+                        import shutil
+
+                        src = Path(intro_outro_config.intro_video_path)
+                        if src.exists():
+                            shutil.copy2(src, intro_path)
+                            intro_ok = True
+                        else:
+                            logger.warning("片头视频不存在，跳过片头: %s", src)
+                    elif intro_outro_config.intro_type == "text":
+                        intro_ok = IntroOutroEngine.generate_text_intro(
+                            intro_path,
+                            intro_outro_config,
+                            self.output_width,
+                            self.output_height,
+                            self.output_fps,
+                        )
+
+                    if not intro_ok:
+                        intro_path = None
+
+                # 生成片尾
+                if intro_outro_config.has_outro:
+                    outro_path = self.work_dir / f"outro_{self.plan.id}.mp4"
+                    outro_ok = False
+                    if intro_outro_config.outro_type == "video":
+                        import shutil
+
+                        src = Path(intro_outro_config.outro_video_path)
+                        if src.exists():
+                            shutil.copy2(src, outro_path)
+                            outro_ok = True
+                        else:
+                            logger.warning("片尾视频不存在，跳过片尾: %s", src)
+                    elif intro_outro_config.outro_type in ("text", "follow"):
+                        outro_ok = IntroOutroEngine.generate_text_outro(
+                            outro_path,
+                            intro_outro_config,
+                            self.output_width,
+                            self.output_height,
+                            self.output_fps,
+                        )
+
+                    if not outro_ok:
+                        outro_path = None
+
+                # 拼接
+                if intro_path or outro_path:
+                    concat_ok = IntroOutroEngine.concat_with_intro_outro(
+                        output_path,
+                        intro_path,
+                        outro_path,
+                        final_with_io,
+                        transition_duration=intro_outro_config.transition_duration,
+                        transition_effect=intro_outro_config.transition_effect,
+                    )
+                    if concat_ok and final_with_io.exists():
+                        output_path = final_with_io
+                        # 重新探测
+                        duration, file_size, width, height = self._probe_output(output_path)
+                        logger.info("[unified-render] 片头片尾拼接完成: plan_id=%s", self.plan.id)
+                    else:
+                        logger.warning("[unified-render] 片头片尾拼接失败，使用原视频: plan_id=%s", self.plan.id)
+            else:
+                logger.warning("[unified-render] 片头片尾配置无效，跳过: %s", io_err)
+
         t_total = int((time.time() - t_start) * 1000)
         logger.info(
             "[unified-render] render done: plan_id=%s total_ms=%d video_ms=%d audio_ms=%d "
@@ -920,6 +1003,7 @@ class UnifiedRenderService:
         """将 EditPlanClip 列表解析为 ResolvedClip 列表。
 
         跳过 asset_id 为空或在 asset_path_map 中找不到的片段。
+        支持多段裁剪：一个 clip 配置了 trim_segments 时会展开为多个 ResolvedClip。
         """
         resolved: list[ResolvedClip] = []
         for clip in self.clips:
@@ -939,17 +1023,75 @@ class UnifiedRenderService:
             except Exception:
                 actual_duration = clip.duration or 5.0
 
+            # 检查是否有多段裁剪配置
+            clip_config = clip.config or {}
+            trim_segments = TrimEngine.parse_segments_from_config(clip_config)
+
+            if trim_segments and len(trim_segments) > 1:
+                # 多段裁剪：展开为多个 clip
+                resolved_segments = TrimEngine.resolve_segments(trim_segments, actual_duration)
+                for i, seg in enumerate(resolved_segments):
+                    # 每个段生成一个独立的 ResolvedClip
+                    seg_clip_id = f"{clip.id}_seg_{seg.segment_id}"
+                    seg_order = clip.order + seg.order * 0.001 + i * 0.0001  # 保持排序
+                    seg_start = seg.trim.start_time
+                    seg_duration = seg.trim.duration
+
+                    rc = ResolvedClip(
+                        clip_id=seg_clip_id,
+                        asset_id=asset_id,
+                        local_path=local_path,
+                        clip_type=clip.clip_type,
+                        order=seg_order,
+                        start_time=seg_start,
+                        duration=seg_duration,
+                        transition_effect=clip.transition_effect or "cut",
+                        config={**clip_config, "_segment_id": seg.segment_id},
+                        actual_duration=actual_duration,
+                        trim_config=seg.trim,
+                    )
+                    resolved.append(rc)
+                continue
+
+            # 单段裁剪（或无裁剪）
+            # 解析裁剪配置：config 优先，否则用 clip.start_time + clip.duration
+            trim_config = extract_trim_from_clip_config(clip_config)
+            if trim_config is None and (clip.start_time > 0 or clip.duration > 0):
+                # 用旧字段构造
+                trim_config = TrimConfig(
+                    start_time=clip.start_time,
+                    duration=clip.duration,
+                )
+
+            # 钳制到实际素材时长
+            effective_trim: TrimConfig | None = None
+            final_start = clip.start_time
+            final_duration = clip.duration
+
+            if trim_config is not None and actual_duration > 0:
+                effective_trim = trim_config.validate_and_resolve(actual_duration)
+                if effective_trim.is_valid:
+                    final_start = effective_trim.start_time
+                    final_duration = effective_trim.duration
+                else:
+                    # 裁剪无效 → 使用完整素材
+                    logger.warning("裁剪配置无效，使用完整素材: clip_id=%s", clip.id)
+                    effective_trim = None
+                    final_start = 0.0
+                    final_duration = actual_duration
+
             rc = ResolvedClip(
                 clip_id=clip.id,
                 asset_id=asset_id,
                 local_path=local_path,
                 clip_type=clip.clip_type,
                 order=clip.order,
-                start_time=clip.start_time,
-                duration=clip.duration,
+                start_time=final_start,
+                duration=final_duration,
                 transition_effect=clip.transition_effect or "cut",
-                config=clip.config or {},
+                config=clip_config,
                 actual_duration=actual_duration,
+                trim_config=effective_trim,
             )
             resolved.append(rc)
 
@@ -1024,7 +1166,7 @@ class UnifiedRenderService:
 
         filter_parts: list[str] = []
 
-        # Step 1: 预处理每个 clip — scale + setpts
+        # Step 1: 预处理每个 clip — trim + scale + setpts
         # 为每个 clip 生成预处理后的标签 [v0], [v1], ...
         preprocessed_labels: list[str] = []
         for i, clip in enumerate(all_clips):
@@ -1033,11 +1175,15 @@ class UnifiedRenderService:
 
             filters: list[str] = []
 
-            # trim — 始终将输出截断到有效时长，防止 xfade offset 与实际时长不匹配
+            # trim — 裁剪到指定区间，精确到帧
             effective_duration = UnifiedRenderService._clip_effective_duration(clip)
+            trim_start = getattr(clip, "start_time", 0) or 0
 
             if effective_duration > 0:
-                filters.append(f"trim=duration={effective_duration}")
+                if trim_start > 0:
+                    filters.append(f"trim=start={trim_start:.3f}:duration={effective_duration:.3f}")
+                else:
+                    filters.append(f"trim=duration={effective_duration:.3f}")
                 filters.append("setpts=PTS-STARTPTS")
 
             # scale
@@ -1138,6 +1284,66 @@ class UnifiedRenderService:
                 filter_parts.append(f"[{final_video_label}][{overlay_label}]" f"overlay={x}:{y}[{combined_label}]")
                 final_video_label = combined_label
 
+        # 叠加水印（在字幕之前）
+        watermark_config = WatermarkConfig.from_dict((self.plan.config or {}).get("watermark"))
+        if watermark_config is not None:
+            wm_valid, wm_err = watermark_config.validate()
+            if wm_valid:
+                wm_label = "watermarked"
+                if watermark_config.mode == "image":
+                    # 图片水印：检查图片是否存在
+                    wm_path = Path(watermark_config.image_path)
+                    if wm_path.exists():
+                        # 图片水印需要额外输入，放在 filter 开头
+                        wm_idx = len(all_clips)  # 水印图是最后一个输入
+                        wm_scale = int(self.output_width * watermark_config.scale)
+
+                        # 透明度
+                        wm_filters = f"scale={wm_scale}:-1"
+                        if watermark_config.opacity < 1.0:
+                            wm_filters += f",format=rgba,colorchannelmixer=aa={watermark_config.opacity}"
+
+                        filter_parts.insert(0, f"[{wm_idx}:v]{wm_filters}[wm_scaled]")
+                        input_args.extend(["-i", str(wm_path)])
+
+                        # 位置计算（水印高度用 scale 后的宽度近似）
+                        wm_h = wm_scale  # 近似（正方形假设）
+                        x, y = WatermarkEngine.calc_position(
+                            watermark_config.position,
+                            self.output_width,
+                            self.output_height,
+                            wm_scale,
+                            wm_h,
+                            watermark_config.margin_x,
+                            watermark_config.margin_y,
+                        )
+
+                        # 滚动水印
+                        if watermark_config.scroll:
+                            x_expr = f"W-mod({watermark_config.scroll_speed}*t\\,W+w)"
+                            overlay = f"[{final_video_label}][wm_scaled]overlay=x={x_expr}:y={y}[{wm_label}]"
+                        else:
+                            overlay = f"[{final_video_label}][wm_scaled]overlay=x={x}:y={y}[{wm_label}]"
+
+                        filter_parts.append(overlay)
+                        final_video_label = wm_label
+                    else:
+                        logger.warning("水印图片不存在，跳过水印: %s", wm_path)
+                elif watermark_config.mode == "text":
+                    # 文字水印
+                    try:
+                        text_wm = WatermarkEngine.build_text_watermark_filter(
+                            f"[{final_video_label}]",
+                            f"[{wm_label}]",
+                            watermark_config,
+                            self.output_width,
+                            self.output_height,
+                        )
+                        filter_parts.append(text_wm)
+                        final_video_label = wm_label
+                    except Exception as e:
+                        logger.warning("文字水印构建失败，跳过: %s", e)
+
         # 叠加字幕（如有）+ 最终像素格式
         if ass_path is not None:
             ass_filter_path = str(ass_path).replace("\\", "/").replace(":", "\\:")
diff --git a/apps/worker/video_processing/watermark_engine.py b/apps/worker/video_processing/watermark_engine.py
new file mode 100755
index 000000000..cc9c802d3
--- /dev/null
+++ b/apps/worker/video_processing/watermark_engine.py
@@ -0,0 +1,315 @@
+"""水印引擎 — 基于 FFmpeg overlay 滤镜的水印叠加.
+
+支持：
+- 图片水印（PNG/logo）
+- 文字水印（drawtext）
+- 9宫格位置 + 边距配置
+- 透明度/大小缩放
+- 滚动水印（跑马灯）
+"""
+
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass
+from typing import Any
+
+logger = logging.getLogger(__name__)
+
+# 9宫格位置枚举
+WATERMARK_POSITIONS = {
+    "top_left": "左上",
+    "top_center": "中上",
+    "top_right": "右上",
+    "center_left": "左中",
+    "center": "中心",
+    "center_right": "右中",
+    "bottom_left": "左下",
+    "bottom_center": "中下",
+    "bottom_right": "右下",
+}
+
+
+@dataclass
+class WatermarkConfig:
+    """水印配置.
+
+    mode: "image" 图片水印 | "text" 文字水印
+    position: 9宫格位置
+    opacity: 透明度 0.0-1.0
+    scale: 缩放比例（图片水印），0.1-1.0
+    margin: 边距（像素）
+    scroll: 是否滚动（跑马灯）
+    scroll_speed: 滚动速度（像素/秒）
+    """
+
+    mode: str = "text"  # image | text
+    position: str = "bottom_right"
+
+    # 图片水印
+    image_path: str = ""  # 本地图片路径
+    scale: float = 0.2  # 相对输出宽度的比例
+    opacity: float = 0.8  # 0.0-1.0
+
+    # 文字水印
+    text: str = ""
+    font_size: int = 24
+    font_color: str = "white"
+    font_path: str = ""  # 字体文件路径
+
+    # 边距
+    margin_x: int = 20
+    margin_y: int = 20
+
+    # 滚动水印
+    scroll: bool = False
+    scroll_speed: int = 50  # 像素/秒
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any] | None) -> WatermarkConfig | None:
+        """从字典构造，空配置返回 None（不加水印）."""
+        if not data:
+            return None
+
+        enabled = data.get("enabled", False)
+        if not enabled:
+            return None
+
+        mode = data.get("mode", "text")
+
+        # 图片模式需要 image_path；文字模式需要 text
+        if mode == "image":
+            image_path = data.get("image_path", "") or data.get("image", "") or ""
+            if not image_path:
+                logger.warning("图片水印缺少 image_path，跳过水印")
+                return None
+        elif mode == "text":
+            text = data.get("text", "") or ""
+            if not text:
+                logger.warning("文字水印缺少 text，跳过水印")
+                return None
+
+        position = data.get("position", "bottom_right")
+        if position not in WATERMARK_POSITIONS:
+            position = "bottom_right"
+
+        return cls(
+            mode=mode,
+            position=position,
+            image_path=str(data.get("image_path", data.get("image", "")) or ""),
+            scale=float(data.get("scale", 0.2)),
+            opacity=float(data.get("opacity", 0.8)),
+            text=str(data.get("text", "") or ""),
+            font_size=int(data.get("font_size", 24)),
+            font_color=str(data.get("font_color", "white")),
+            font_path=str(data.get("font_path", "") or ""),
+            margin_x=int(data.get("margin_x", 20)),
+            margin_y=int(data.get("margin_y", 20)),
+            scroll=bool(data.get("scroll", False)),
+            scroll_speed=int(data.get("scroll_speed", 50)),
+        )
+
+    def validate(self) -> tuple[bool, str]:
+        """校验配置是否有效."""
+        if self.position not in WATERMARK_POSITIONS:
+            return False, f"不支持的位置: {self.position}"
+
+        if not (0.0 <= self.opacity <= 1.0):
+            return False, "透明度必须在 0-1 之间"
+
+        if self.mode == "image":
+            if not self.image_path:
+                return False, "图片水印缺少图片路径"
+            if not (0.01 <= self.scale <= 1.0):
+                return False, "缩放比例必须在 0.01-1.0 之间"
+        elif self.mode == "text":
+            if not self.text:
+                return False, "文字水印缺少文字内容"
+            if self.font_size <= 0:
+                return False, "字体大小必须大于 0"
+        else:
+            return False, f"不支持的水印模式: {self.mode}"
+
+        return True, ""
+
+
+class WatermarkEngine:
+    """水印引擎 — 生成 FFmpeg 水印滤镜."""
+
+    @staticmethod
+    def calc_position(
+        position: str,
+        output_width: int,
+        output_height: int,
+        wm_width: int,
+        wm_height: int,
+        margin_x: int,
+        margin_y: int,
+    ) -> tuple[int, int]:
+        """根据9宫格位置计算水印坐标 (x, y).
+
+        坐标系：左上角为 (0, 0)
+        """
+        if position == "top_left":
+            return margin_x, margin_y
+        elif position == "top_center":
+            return (output_width - wm_width) // 2, margin_y
+        elif position == "top_right":
+            return output_width - wm_width - margin_x, margin_y
+        elif position == "center_left":
+            return margin_x, (output_height - wm_height) // 2
+        elif position == "center":
+            return (output_width - wm_width) // 2, (output_height - wm_height) // 2
+        elif position == "center_right":
+            return output_width - wm_width - margin_x, (output_height - wm_height) // 2
+        elif position == "bottom_left":
+            return margin_x, output_height - wm_height - margin_y
+        elif position == "bottom_center":
+            return (output_width - wm_width) // 2, output_height - wm_height - margin_y
+        elif position == "bottom_right":
+            return output_width - wm_width - margin_x, output_height - wm_height - margin_y
+        else:
+            # 默认右下角
+            return output_width - wm_width - margin_x, output_height - wm_height - margin_y
+
+    @staticmethod
+    def calc_scroll_x(position: str, output_width: int, wm_width: int, speed: int) -> str:
+        """生成滚动水印的 x 坐标表达式.
+
+        从右向左滚动（跑马灯效果）
+        """
+        # x 从 W 到 -wm_width，整个宽度 + wm_width 的距离
+        # 使用 overlay 的 enable 表达式
+        # x = 'W - (t * speed)' → 不对，应该是持续滚动
+        # 标准跑马灯：x = -w + (t * speed) % (W + w)
+        # 但 FFmpeg overlay 支持表达式
+        return f"mod({output_width}-mod({speed}*t\\,{output_width}+{wm_width})"
+
+    @staticmethod
+    def build_image_watermark_filter(
+        input_video_label: str,
+        wm_image_path: str,
+        output_width: int,
+        output_height: int,
+        output_label: str,
+        config: WatermarkConfig,
+    ) -> tuple[str, list[str]]:
+        """构建图片水印滤镜链.
+
+        Args:
+            input_video_label: 输入视频标签，如 "[final_video]"
+            wm_image_path: 水印图片本地路径
+            output_width: 输出视频宽度
+            output_height: 输出视频高度
+            output_label: 输出标签
+            config: 水印配置
+
+        Returns:
+            (filter_complex_str, input_args_list)
+            input_args 是 ["-i", wm_image_path] 格式
+        """
+        # 计算水印尺寸（按输出宽度比例缩放）
+        wm_width = int(output_width * config.scale)
+        wm_height = -1  # 保持比例
+        wm_filter = f"scale={wm_width}:{wm_height}"
+
+        # 透明度处理
+        if config.opacity < 1.0:
+            wm_filter += f",format=rgba,colorchannelmixer=aa={config.opacity}"
+
+        # 水印预处理标签
+        wm_pre_label = "[wm_scaled]"
+
+        # 计算位置
+        x, y = WatermarkEngine.calc_position(
+            config.position,
+            output_width,
+            output_height,
+            wm_width,
+            wm_width,  # 高度未知，先用宽度估算
+            config.margin_x,
+            config.margin_y,
+        )
+
+        # 滚动水印
+        if config.scroll:
+            # 从右向左滚动：x = W - (t * speed) mod (W + wm_w)
+            # 使用 overlay 表达式
+            x_expr = f"{output_width}-mod({config.scroll_speed}*t\\,{output_width}+{wm_width}"
+            y_expr = str(y)
+            overlay_expr = f"x={x_expr}:y={y_expr}"
+        else:
+            overlay_expr = f"x={x}:y={y}"
+
+        # 构建滤镜
+        # 先缩放水印图
+        wm_input_idx = 1  # 假设水印图是第二个输入（索引1
+        filter_parts = [
+            f"[1:v]{wm_filter}{wm_pre_label}",
+            f"{input_video_label}{wm_pre_label}overlay={overlay_expr}{output_label}",
+        ]
+
+        filter_complex = ";".join(filter_parts)
+        input_args = ["-i", wm_image_path]
+
+        return filter_complex, input_args
+
+    @staticmethod
+    def build_text_watermark_filter(
+        input_video_label: str,
+        output_label: str,
+        config: WatermarkConfig,
+        output_width: int,
+        output_height: int,
+    ) -> str:
+        """构建文字水印滤镜（drawtext）.
+
+        Args:
+            input_video_label: 输入视频标签
+            output_label: 输出标签
+            config: 水印配置
+            output_width: 输出宽度
+            output_height: 输出高度
+
+        Returns:
+            FFmpeg filter 字符串
+        """
+        # 转义文字中的特殊字符
+        text = config.text.replace(":", "\\:").replace("'", "\\'")
+
+        # 字体配置
+        font_config = []
+        if config.font_path:
+            font_path_escaped = config.font_path.replace(":", "\\:").replace("'", "\\'")
+            font_config.append(f"fontfile='{font_path_escaped}'")
+        font_config.append(f"fontsize={config.font_size}")
+        font_config.append(f"fontcolor={config.font_color}@{config.opacity}")
+
+        # 估算文字宽高（粗略估算，用于位置计算）
+        # 每个汉字约等于 font_size 宽高
+        approx_w = len(config.text) * config.font_size
+        approx_h = config.font_size
+
+        # 位置计算
+        x, y = WatermarkEngine.calc_position(
+            config.position,
+            output_width,
+            output_height,
+            approx_w,
+            approx_h,
+            config.margin_x,
+            config.margin_y,
+        )
+
+        # 滚动水印
+        if config.scroll:
+            x_expr = f"w-mod({config.scroll_speed}*t\\,W+w)"
+            pos_config = [f"x={x_expr}", f"y={y}"]
+        else:
+            pos_config = [f"x={x}", f"y={y}"]
+
+        # 组装 drawtext
+        drawtext_parts = [f"text='{text}'"] + font_config + pos_config
+        drawtext = "drawtext=" + ":".join(drawtext_parts)
+
+        return f"{input_video_label}{drawtext}{output_label}"
diff --git a/tests/unit/test_trim_engine.py b/tests/unit/test_trim_engine.py
new file mode 100755
index 000000000..d6b7a8eb8
--- /dev/null
+++ b/tests/unit/test_trim_engine.py
@@ -0,0 +1,268 @@
+"""裁剪引擎单元测试."""
+
+import sys
+import unittest
+from pathlib import Path
+
+# 确保 apps/worker 在路径中
+sys.path.insert(0, str(Path(__file__).parent.parent.parent / "apps" / "worker"))
+
+from video_processing.trim_engine import (
+    MIN_TRIM_DURATION,
+    TrimConfig,
+    TrimEngine,
+    TrimSegment,
+    extract_trim_from_clip_config,
+)
+
+
+class TestTrimConfig(unittest.TestCase):
+    """TrimConfig 单元测试."""
+
+    def test_from_dict_none(self):
+        """空字典返回 None（不裁剪）."""
+        self.assertIsNone(TrimConfig.from_dict(None))
+        self.assertIsNone(TrimConfig.from_dict({}))
+
+    def test_from_dict_with_start(self):
+        """只有 start_time."""
+        cfg = TrimConfig.from_dict({"start_time": 5.0})
+        self.assertIsNotNone(cfg)
+        self.assertEqual(cfg.start_time, 5.0)
+        self.assertEqual(cfg.end_time, 0.0)
+        self.assertEqual(cfg.duration, 0.0)
+
+    def test_from_dict_with_duration(self):
+        """只有 duration."""
+        cfg = TrimConfig.from_dict({"duration": 10.0})
+        self.assertIsNotNone(cfg)
+        self.assertEqual(cfg.start_time, 0.0)
+        self.assertEqual(cfg.duration, 10.0)
+
+    def test_resolve_start_and_end(self):
+        """start + end 推导 duration."""
+        cfg = TrimConfig(start_time=5.0, end_time=15.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        self.assertEqual(resolved.start_time, 5.0)
+        self.assertEqual(resolved.end_time, 15.0)
+        self.assertAlmostEqual(resolved.duration, 10.0, places=3)
+        self.assertTrue(resolved.is_valid)
+
+    def test_resolve_start_and_duration(self):
+        """start + duration 推导 end."""
+        cfg = TrimConfig(start_time=5.0, duration=10.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        self.assertEqual(resolved.start_time, 5.0)
+        self.assertAlmostEqual(resolved.end_time, 15.0, places=3)
+        self.assertEqual(resolved.duration, 10.0)
+
+    def test_resolve_end_and_duration(self):
+        """end + duration 推导 start."""
+        cfg = TrimConfig(end_time=20.0, duration=8.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        self.assertAlmostEqual(resolved.start_time, 12.0, places=3)
+        self.assertEqual(resolved.end_time, 20.0)
+        self.assertEqual(resolved.duration, 8.0)
+
+    def test_resolve_only_start(self):
+        """只有 start → 取到末尾."""
+        cfg = TrimConfig(start_time=10.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        self.assertEqual(resolved.start_time, 10.0)
+        self.assertEqual(resolved.end_time, 30.0)
+        self.assertAlmostEqual(resolved.duration, 20.0, places=3)
+
+    def test_resolve_only_duration(self):
+        """只有 duration → 从开头取."""
+        cfg = TrimConfig(duration=15.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        self.assertEqual(resolved.start_time, 0.0)
+        self.assertAlmostEqual(resolved.end_time, 15.0, places=3)
+        self.assertEqual(resolved.duration, 15.0)
+
+    def test_boundary_clamp_end(self):
+        """end 超出素材时长 → 钳制."""
+        cfg = TrimConfig(start_time=5.0, duration=30.0)
+        resolved = cfg.validate_and_resolve(asset_duration=20.0)
+        self.assertEqual(resolved.start_time, 5.0)
+        self.assertEqual(resolved.end_time, 20.0)
+        self.assertAlmostEqual(resolved.duration, 15.0, places=3)
+
+    def test_boundary_clamp_start_negative(self):
+        """start 为负 → 钳制到 0."""
+        cfg = TrimConfig(start_time=-5.0, duration=10.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        self.assertEqual(resolved.start_time, 0.0)
+        self.assertAlmostEqual(resolved.end_time, 10.0, places=3)
+        self.assertEqual(resolved.duration, 10.0)
+
+    def test_boundary_start_past_end(self):
+        """start 超过素材总时长 → 钳制到末尾最小片段."""
+        cfg = TrimConfig(start_time=50.0, duration=5.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        self.assertTrue(resolved.start_time < 30.0)
+        self.assertEqual(resolved.end_time, 30.0)
+        self.assertTrue(resolved.duration >= MIN_TRIM_DURATION)
+
+    def test_invalid_end_before_start(self):
+        """end <= start → 无效."""
+        cfg = TrimConfig(start_time=15.0, end_time=10.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        self.assertFalse(resolved.is_valid)
+
+    def test_zero_duration_invalid(self):
+        """duration 为 0 → 无效."""
+        cfg = TrimConfig(start_time=5.0, duration=0.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        # 只有 start 没有 duration → 会被推导为取到末尾
+        self.assertTrue(resolved.is_valid)
+        self.assertEqual(resolved.end_time, 30.0)
+
+    def test_is_noop(self):
+        """is_noop 判断."""
+        noop = TrimConfig(start_time=0.0, end_time=0.0, duration=0.0)
+        self.assertTrue(noop.is_noop)
+
+        not_noop = TrimConfig(start_time=5.0, duration=10.0)
+        self.assertFalse(not_noop.is_noop)
+
+    def test_zero_asset_duration(self):
+        """素材时长为 0 → 不裁剪."""
+        cfg = TrimConfig(start_time=5.0, duration=10.0)
+        resolved = cfg.validate_and_resolve(asset_duration=0.0)
+        self.assertTrue(resolved.is_noop)
+
+    def test_all_three_params_use_start_duration(self):
+        """三个参数都给了 → 以 start + duration 为准."""
+        cfg = TrimConfig(start_time=5.0, end_time=20.0, duration=8.0)
+        resolved = cfg.validate_and_resolve(asset_duration=30.0)
+        # validate_and_resolve 中 start+end 优先于 start+duration
+        # 因为先检查的是 start>0 and end>0
+        self.assertAlmostEqual(resolved.duration, 15.0, places=3)
+
+
+class TestTrimEngine(unittest.TestCase):
+    """TrimEngine 单元测试."""
+
+    def test_build_video_trim_with_start_and_duration(self):
+        """视频裁剪：start + duration."""
+        trim = TrimConfig(start_time=10.0, duration=5.0)
+        result = TrimEngine.build_video_trim_filter("[0:v]", trim, "[v0]")
+        self.assertIn("trim=start=10.000:duration=5.000", result)
+        self.assertIn("setpts=PTS-STARTPTS", result)
+        self.assertTrue(result.startswith("[0:v]"))
+        self.assertTrue(result.endswith("[v0]"))
+
+    def test_build_video_trim_duration_only(self):
+        """视频裁剪：只有 duration."""
+        trim = TrimConfig(start_time=0.0, duration=8.0)
+        result = TrimEngine.build_video_trim_filter("[0:v]", trim, "[v0]")
+        self.assertIn("trim=duration=8.000", result)
+        self.assertNotIn("start=", result.split("setpts")[0])
+
+    def test_build_audio_trim_with_start(self):
+        """音频裁剪：start + duration."""
+        trim = TrimConfig(start_time=3.0, duration=7.0)
+        result = TrimEngine.build_audio_trim_filter("[0:a]", trim, "[a0]")
+        self.assertIn("atrim=start=3.000:duration=7.000", result)
+        self.assertIn("asetpts=PTS-STARTPTS", result)
+
+    def test_build_audio_trim_noop(self):
+        """音频裁剪：noop."""
+        trim = TrimConfig(start_time=0.0, end_time=0.0, duration=0.0)
+        result = TrimEngine.build_audio_trim_filter("[0:a]", trim, "[a0]")
+        self.assertIn("asetpts=PTS-STARTPTS", result)
+        self.assertNotIn("atrim=", result)
+
+    def test_resolve_segments(self):
+        """多段裁剪解析."""
+        segments = [
+            TrimSegment(segment_id="s1", trim=TrimConfig(start_time=0.0, duration=5.0), order=0),
+            TrimSegment(segment_id="s2", trim=TrimConfig(start_time=10.0, duration=5.0), order=1),
+            TrimSegment(segment_id="s3", trim=TrimConfig(start_time=20.0, duration=5.0), order=2),
+        ]
+        resolved = TrimEngine.resolve_segments(segments, asset_duration=30.0)
+        self.assertEqual(len(resolved), 3)
+        self.assertEqual(resolved[0].segment_id, "s1")
+        self.assertEqual(resolved[0].trim.duration, 5.0)
+        self.assertEqual(resolved[1].segment_id, "s2")
+        self.assertEqual(resolved[1].trim.start_time, 10.0)
+        self.assertEqual(resolved[2].trim.start_time, 20.0)
+
+    def test_resolve_segments_filter_invalid(self):
+        """多段裁剪：过滤无效段."""
+        segments = [
+            TrimSegment(segment_id="good", trim=TrimConfig(start_time=0.0, duration=5.0), order=0),
+            TrimSegment(segment_id="bad", trim=TrimConfig(start_time=10.0, end_time=5.0), order=1),  # end < start
+        ]
+        resolved = TrimEngine.resolve_segments(segments, asset_duration=30.0)
+        self.assertEqual(len(resolved), 1)
+        self.assertEqual(resolved[0].segment_id, "good")
+
+    def test_resolve_segments_boundary_clamp(self):
+        """多段裁剪：边界钳制."""
+        segments = [
+            TrimSegment(segment_id="s1", trim=TrimConfig(start_time=25.0, duration=10.0), order=0),
+        ]
+        resolved = TrimEngine.resolve_segments(segments, asset_duration=30.0)
+        self.assertEqual(len(resolved), 1)
+        self.assertEqual(resolved[0].trim.end_time, 30.0)
+        self.assertAlmostEqual(resolved[0].trim.duration, 5.0, places=3)
+
+    def test_parse_segments_from_list(self):
+        """从 config 解析多段配置."""
+        config = {
+            "trim_segments": [
+                {"segment_id": "intro", "start_time": 0, "duration": 3, "order": 0},
+                {"segment_id": "highlight", "start_time": 10, "duration": 5, "order": 1},
+                {"segment_id": "outro", "start_time": 50, "duration": 3, "order": 2},
+            ]
+        }
+        segments = TrimEngine.parse_segments_from_config(config)
+        self.assertEqual(len(segments), 3)
+        self.assertEqual(segments[0].segment_id, "intro")
+        self.assertEqual(segments[1].trim.start_time, 10.0)
+        self.assertEqual(segments[2].trim.duration, 3.0)
+
+    def test_parse_segments_empty(self):
+        """无裁剪配置 → 空列表."""
+        self.assertEqual(TrimEngine.parse_segments_from_config(None), [])
+        self.assertEqual(TrimEngine.parse_segments_from_config({}), [])
+
+    def test_parse_single_trim_legacy(self):
+        """旧格式单段裁剪（trim_start/trim_duration）."""
+        config = {"trim_start": 5.0, "trim_duration": 10.0}
+        segments = TrimEngine.parse_segments_from_config(config)
+        self.assertEqual(len(segments), 1)
+        self.assertEqual(segments[0].trim.start_time, 5.0)
+        self.assertEqual(segments[0].trim.duration, 10.0)
+
+
+class TestExtractTrimFromClipConfig(unittest.TestCase):
+    """extract_trim_from_clip_config 单元测试."""
+
+    def test_trim_subdict(self):
+        """trim 子字典."""
+        config = {"trim": {"start_time": 5.0, "duration": 10.0}}
+        result = extract_trim_from_clip_config(config)
+        self.assertIsNotNone(result)
+        self.assertEqual(result.start_time, 5.0)
+        self.assertEqual(result.duration, 10.0)
+
+    def test_flat_fields(self):
+        """扁平字段（trim_start/trim_end/trim_duration）."""
+        config = {"trim_start": 2.0, "trim_end": 8.0}
+        result = extract_trim_from_clip_config(config)
+        self.assertIsNotNone(result)
+        self.assertEqual(result.start_time, 2.0)
+        self.assertEqual(result.end_time, 8.0)
+
+    def test_no_trim(self):
+        """无裁剪配置."""
+        self.assertIsNone(extract_trim_from_clip_config(None))
+        self.assertIsNone(extract_trim_from_clip_config({}))
+        self.assertIsNone(extract_trim_from_clip_config({"other": "value"}))
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/unit/test_watermark_intro_outro.py b/tests/unit/test_watermark_intro_outro.py
new file mode 100755
index 000000000..05b2d0c1d
--- /dev/null
+++ b/tests/unit/test_watermark_intro_outro.py
@@ -0,0 +1,344 @@
+"""水印 + 片头片尾引擎单元测试."""
+
+import sys
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent.parent.parent / "apps" / "worker"))
+
+from video_processing.intro_outro_engine import (
+    IntroOutroConfig,
+    IntroOutroEngine,
+)
+from video_processing.watermark_engine import (
+    WATERMARK_POSITIONS,
+    WatermarkConfig,
+    WatermarkEngine,
+)
+
+
+class TestWatermarkConfig(unittest.TestCase):
+    """WatermarkConfig 单元测试."""
+
+    def test_from_dict_none_disabled(self):
+        """空配置或未启用 → None."""
+        self.assertIsNone(WatermarkConfig.from_dict(None))
+        self.assertIsNone(WatermarkConfig.from_dict({}))
+        self.assertIsNone(WatermarkConfig.from_dict({"enabled": False}))
+
+    def test_from_dict_text_mode(self):
+        """文字水印模式."""
+        cfg = WatermarkConfig.from_dict({
+            "enabled": True,
+            "mode": "text",
+            "text": "hello world",
+            "position": "top_left",
+        })
+        self.assertIsNotNone(cfg)
+        self.assertEqual(cfg.mode, "text")
+        self.assertEqual(cfg.text, "hello world")
+        self.assertEqual(cfg.position, "top_left")
+
+    def test_from_dict_image_missing_path(self):
+        """图片水印缺路径 → None."""
+        cfg = WatermarkConfig.from_dict({
+            "enabled": True,
+            "mode": "image",
+        })
+        self.assertIsNone(cfg)
+
+    def test_from_dict_text_missing_text(self):
+        """文字水印缺文字 → None."""
+        cfg = WatermarkConfig.from_dict({
+            "enabled": True,
+            "mode": "text",
+        })
+        self.assertIsNone(cfg)
+
+    def test_validate_text_valid(self):
+        """文字水印合法配置."""
+        cfg = WatermarkConfig(
+            mode="text",
+            text="test",
+            position="bottom_right",
+        )
+        ok, err = cfg.validate()
+        self.assertTrue(ok)
+        self.assertEqual(err, "")
+
+    def test_validate_invalid_position(self):
+        """非法位置."""
+        cfg = WatermarkConfig(mode="text", text="test", position="invalid")
+        ok, err = cfg.validate()
+        self.assertFalse(ok)
+        self.assertIn("不支持的位置", err)
+
+    def test_validate_opacity_out_of_range(self):
+        """透明度超范围."""
+        cfg = WatermarkConfig(mode="text", text="test", opacity=1.5)
+        ok, err = cfg.validate()
+        self.assertFalse(ok)
+
+    def test_validate_image_missing_path(self):
+        """图片水印缺路径."""
+        cfg = WatermarkConfig(mode="image")
+        ok, err = cfg.validate()
+        self.assertFalse(ok)
+
+
+class TestWatermarkEnginePosition(unittest.TestCase):
+    """水印位置计算单元测试."""
+
+    def setUp(self):
+        self.out_w = 1920
+        self.out_h = 1080
+        self.wm_w = 200
+        self.wm_h = 100
+        self.mx = 20
+        self.my = 20
+
+    def test_top_left(self):
+        x, y = WatermarkEngine.calc_position(
+            "top_left", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, 20)
+        self.assertEqual(y, 20)
+
+    def test_top_center(self):
+        x, y = WatermarkEngine.calc_position(
+            "top_center", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, (1920 - 200) // 2)
+        self.assertEqual(y, 20)
+
+    def test_top_right(self):
+        x, y = WatermarkEngine.calc_position(
+            "top_right", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, 1920 - 200 - 20)
+        self.assertEqual(y, 20)
+
+    def test_center_left(self):
+        x, y = WatermarkEngine.calc_position(
+            "center_left", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, 20)
+        self.assertEqual(y, (1080 - 100) // 2)
+
+    def test_center(self):
+        x, y = WatermarkEngine.calc_position(
+            "center", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, (1920 - 200) // 2)
+        self.assertEqual(y, (1080 - 100) // 2)
+
+    def test_center_right(self):
+        x, y = WatermarkEngine.calc_position(
+            "center_right", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, 1920 - 200 - 20)
+        self.assertEqual(y, (1080 - 100) // 2)
+
+    def test_bottom_left(self):
+        x, y = WatermarkEngine.calc_position(
+            "bottom_left", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, 20)
+        self.assertEqual(y, 1080 - 100 - 20)
+
+    def test_bottom_center(self):
+        x, y = WatermarkEngine.calc_position(
+            "bottom_center", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, (1920 - 200) // 2)
+        self.assertEqual(y, 1080 - 100 - 20)
+
+    def test_bottom_right(self):
+        x, y = WatermarkEngine.calc_position(
+            "bottom_right", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, 1920 - 200 - 20)
+        self.assertEqual(y, 1080 - 100 - 20)
+
+    def test_default_fallback(self):
+        """非法位置默认右下角."""
+        x, y = WatermarkEngine.calc_position(
+            "unknown", self.out_w, self.out_h, self.wm_w, self.wm_h, self.mx, self.my
+        )
+        self.assertEqual(x, 1920 - 200 - 20)
+        self.assertEqual(y, 1080 - 100 - 20)
+
+    def test_nine_positions_all_present(self):
+        """9宫格位置都有定义."""
+        self.assertEqual(len(WATERMARK_POSITIONS), 9)
+
+
+class TestWatermarkEngineFilters(unittest.TestCase):
+    """水印滤镜构建单元测试."""
+
+    def test_text_watermark_filter(self):
+        """文字水印滤镜构建."""
+        cfg = WatermarkConfig(
+            mode="text",
+            text="hello",
+            position="top_left",
+            font_size=24,
+            font_color="white",
+            opacity=0.8,
+            margin_x=10,
+            margin_y=10,
+        )
+        result = WatermarkEngine.build_text_watermark_filter(
+            "[in]", "[out]", cfg, 1920, 1080
+        )
+        self.assertTrue(result.startswith("[in]drawtext="))
+        self.assertIn("text='hello'", result)
+        self.assertIn("fontsize=24", result)
+        self.assertIn("fontcolor=white@0.8", result)
+        self.assertTrue(result.endswith("[out]"))
+
+    def test_text_watermark_scroll(self):
+        """滚动文字水印."""
+        cfg = WatermarkConfig(
+            mode="text",
+            text="scroll",
+            position="bottom_left",
+            scroll=True,
+            scroll_speed=60,
+        )
+        result = WatermarkEngine.build_text_watermark_filter(
+            "[in]", "[out]", cfg, 1920, 1080
+        )
+        self.assertIn("mod(60*t", result)
+
+
+class TestIntroOutroConfig(unittest.TestCase):
+    """IntroOutroConfig 单元测试."""
+
+    def test_from_dict_disabled(self):
+        """未启用 → 空配置."""
+        cfg = IntroOutroConfig.from_dict(None)
+        self.assertFalse(cfg.enabled)
+        self.assertFalse(cfg.has_intro)
+        self.assertFalse(cfg.has_outro)
+
+    def test_from_dict_intro_text(self):
+        """文字片头配置."""
+        cfg = IntroOutroConfig.from_dict({
+            "enabled": True,
+            "intro": {
+                "type": "text",
+                "title": "欢迎观看",
+                "subtitle": "精彩内容马上开始",
+                "duration": 3.0,
+                "background": "#1a1a2e",
+            },
+        })
+        self.assertTrue(cfg.enabled)
+        self.assertTrue(cfg.has_intro)
+        self.assertFalse(cfg.has_outro)
+        self.assertEqual(cfg.intro_type, "text")
+        self.assertEqual(cfg.intro_title, "欢迎观看")
+        self.assertEqual(cfg.intro_duration, 3.0)
+
+    def test_from_dict_outro_video(self):
+        """视频片尾配置."""
+        cfg = IntroOutroConfig.from_dict({
+            "enabled": True,
+            "outro": {
+                "type": "video",
+                "video_path": "/tmp/outro.mp4",
+                "duration": 5.0,
+            },
+        })
+        self.assertTrue(cfg.has_outro)
+        self.assertEqual(cfg.outro_type, "video")
+        self.assertEqual(cfg.outro_video_path, "/tmp/outro.mp4")
+
+    def test_validate_valid(self):
+        """合法配置."""
+        cfg = IntroOutroConfig(
+            enabled=True,
+            intro_type="text",
+            intro_title="标题",
+            intro_duration=3.0,
+            outro_type="text",
+            outro_title="片尾",
+            outro_duration=3.0,
+        )
+        ok, err = cfg.validate()
+        self.assertTrue(ok)
+
+    def test_validate_video_intro_missing_path(self):
+        """视频片头缺路径."""
+        cfg = IntroOutroConfig(
+            enabled=True,
+            intro_type="video",
+            intro_duration=3.0,
+        )
+        ok, err = cfg.validate()
+        self.assertFalse(ok)
+        self.assertIn("video_path", err)
+
+    def test_validate_text_intro_missing_title(self):
+        """文字片头缺标题."""
+        cfg = IntroOutroConfig(
+            enabled=True,
+            intro_type="text",
+            intro_duration=3.0,
+        )
+        ok, err = cfg.validate()
+        self.assertFalse(ok)
+
+    def test_has_intro_false_when_none(self):
+        """type=none 时 has_intro 为 False."""
+        cfg = IntroOutroConfig(enabled=True, intro_type="none")
+        self.assertFalse(cfg.has_intro)
+
+    def test_has_outro_follow_type(self):
+        """follow 类型也算有片尾."""
+        cfg = IntroOutroConfig(enabled=True, outro_type="follow", outro_title="关注")
+        self.assertTrue(cfg.has_outro)
+
+
+class TestIntroOutroEngineConcat(unittest.TestCase):
+    """片头片尾拼接单元测试."""
+
+    def test_concat_no_intro_outro(self):
+        """没有片头片尾 → 直接复制."""
+        import tempfile
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            main_video = Path(tmpdir) / "main.mp4"
+            output = Path(tmpdir) / "output.mp4"
+            # 创建空文件模拟
+            main_video.write_bytes(b"fake video data")
+
+            result = IntroOutroEngine.concat_with_intro_outro(
+                main_video, None, None, output
+            )
+            self.assertTrue(result)
+            self.assertTrue(output.exists())
+            self.assertEqual(main_video.read_bytes(), output.read_bytes())
+
+    def test_concat_intro_only_no_file(self):
+        """只有片头但文件不存在 → 直接复制主视频."""
+        import tempfile
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            main_video = Path(tmpdir) / "main.mp4"
+            output = Path(tmpdir) / "output.mp4"
+            main_video.write_bytes(b"fake data")
+
+            # intro 路径不存在
+            intro = Path(tmpdir) / "nonexistent.mp4"
+
+            result = IntroOutroEngine.concat_with_intro_outro(
+                main_video, intro, None, output
+            )
+            self.assertTrue(result)
+            self.assertTrue(output.exists())
+
+
+if __name__ == "__main__":
+    unittest.main()