diff --git a/apps/worker/video_processing/speed_engine.py b/apps/worker/video_processing/speed_engine.py
index 1ab365b17..cc9798f65 100755
--- a/apps/worker/video_processing/speed_engine.py
+++ b/apps/worker/video_processing/speed_engine.py
@@ -1,4 +1,4 @@
-"""视频调速引擎 — 基于 FFmpeg setpts + atempo 的速度调整能力。
+"""视频调速引擎 — 基于 FFmpeg setpts + atempo 的速度调整能力.
 
 支持：
 - 0.25x ~ 4x 变速范围
@@ -6,147 +6,57 @@
 - 音频调速（atempo，多级串联处理超范围值）
 - 音调修正（pitch_correct，默认开启）
 - 边界自动钳制，不阻断渲染
+
+注：核心领域模型已抽离到 packages/domain/speed_config.py，
+本模块保留薄包装层，确保向后兼容。
 """
 
-from dataclasses import dataclass
+from __future__ import annotations
+
 from typing import Optional
 
-# ─── 常量 ───────────────────────────────────────────────
-MIN_SPEED = 0.25
-MAX_SPEED = 4.0
-DEFAULT_SPEED = 1.0
-
-# atempo 单级有效范围
-_ATEMPO_MIN = 0.5
-_ATEMPO_MAX = 2.0
-
-
-@dataclass
-class SpeedConfig:
-    """调速配置。
-
-    Attributes:
-        speed: 播放速度，0.25~4.0，1.0 为原速
-        pitch_correct: 是否保持音调（默认 True，用 atempo 时间拉伸算法）
-    """
-
-    speed: float = DEFAULT_SPEED
-    pitch_correct: bool = True
-
-    @classmethod
-    def parse(cls, data: Optional[dict]) -> "SpeedConfig":
-        """从 dict 解析配置，无效值回退到默认。"""
-        if not data or not isinstance(data, dict):
-            return cls()
-
-        speed = data.get("speed", DEFAULT_SPEED)
-        if not isinstance(speed, (int, float)):
-            speed = DEFAULT_SPEED
-
-        pitch_correct = data.get("pitch_correct", True)
-        if not isinstance(pitch_correct, bool):
-            pitch_correct = True
-
-        config = cls(speed=float(speed), pitch_correct=pitch_correct)
-        config.clamp()
-        return config
-
-    def clamp(self) -> None:
-        """将速度钳制到合法范围。"""
-        if self.speed <= 0:
-            self.speed = DEFAULT_SPEED
-        elif self.speed < MIN_SPEED:
-            self.speed = MIN_SPEED
-        elif self.speed > MAX_SPEED:
-            self.speed = MAX_SPEED
-
-    @property
-    def is_original(self) -> bool:
-        """是否原速（无需调速）。"""
-        return abs(self.speed - 1.0) < 1e-6
+from packages.domain.speed_config import (  # noqa: F401 — 向后兼容
+    DEFAULT_SPEED,
+    MAX_SPEED,
+    MIN_SPEED,
+    SpeedConfig,
+    _split_atempo_stages,
+    adjust_duration as _adjust_duration_base,
+    build_audio_filter as _build_audio_filter_base,
+    build_video_filter as _build_video_filter_base,
+    resolve_clip_speed as _resolve_clip_speed_base,
+)
 
 
 class SpeedEngine:
-    """调速引擎 — 生成 FFmpeg 调速滤镜链。
+    """调速引擎 — 生成 FFmpeg 调速滤镜链.
 
-    用法：
-        engine = SpeedEngine()
-        video_filter = engine.build_video_filter(config)
-        audio_filter = engine.build_audio_filter(config)
-        new_duration = engine.adjust_duration(duration, config)
+    薄包装层，实际逻辑委托给 packages.domain.speed_config。
     """
 
     def build_video_filter(self, config: SpeedConfig) -> str:
-        """生成视频调速滤镜字符串。
-
-        返回 setpts 滤镜表达式，原速时返回空字符串。
-        """
-        if config.is_original:
-            return ""
-        # setpts=PTS/speed — speed>1 加速，speed<1 减速
-        return f"setpts=PTS/{config.speed:.4f}"
+        """生成视频调速滤镜字符串."""
+        return _build_video_filter_base(config)
 
     def build_audio_filter(self, config: SpeedConfig) -> str:
-        """生成音频调速滤镜字符串。
-
-        atempo 单级范围 0.5~2.0，超出范围时自动多级串联：
-        - 0.25x → atempo=0.5,atempo=0.5
-        - 4x → atempo=2.0,atempo=2.0
-        - 0.3x → atempo=0.5,atempo=0.6
-        - 3x → atempo=2.0,atempo=1.5
-
-        原速时返回空字符串。
-        """
-        if config.is_original:
-            return ""
-
-        speed = config.speed
-        stages: list[float] = self._split_atempo_stages(speed)
-        return ",".join(f"atempo={s:.4f}" for s in stages)
+        """生成音频调速滤镜字符串."""
+        return _build_audio_filter_base(config)
 
     @staticmethod
     def _split_atempo_stages(speed: float) -> list[float]:
-        """将速度拆分为多级 atempo 串联，每级都在 [0.5, 2.0] 范围内。"""
-        if _ATEMPO_MIN <= speed <= _ATEMPO_MAX:
-            return [speed]
-
-        stages: list[float] = []
-        remaining = speed
-
-        # 加速场景（speed > 2.0）
-        if speed > _ATEMPO_MAX:
-            while remaining > _ATEMPO_MAX:
-                stages.append(_ATEMPO_MAX)
-                remaining /= _ATEMPO_MAX
-            stages.append(remaining)
-
-        # 减速场景（speed < 0.5）
-        else:
-            while remaining < _ATEMPO_MIN:
-                stages.append(_ATEMPO_MIN)
-                remaining /= _ATEMPO_MIN
-            stages.append(remaining)
-
-        return stages
+        """将速度拆分为多级 atempo 串联（内部方法，向后兼容）."""
+        return _split_atempo_stages(speed)
 
     def adjust_duration(self, original_duration: float, config: SpeedConfig) -> float:
-        """计算调速后的时长。
-
-        加速 → 时长变短；减速 → 时长变长。
-        """
-        if config.is_original or original_duration <= 0:
-            return original_duration
-        return original_duration / config.speed
+        """计算调速后的时长."""
+        return _adjust_duration_base(original_duration, config)
 
     def build_clip_speed_filter(
         self,
         speed: float,
         pitch_correct: bool = True,
     ) -> tuple[str, str, SpeedConfig]:
-        """便捷方法：从单一 speed 值生成视频+音频滤镜。
-
-        返回 (video_filter, audio_filter, config)。
-        """
+        """便捷方法：从单一 speed 值生成视频+音频滤镜."""
         config = SpeedConfig(speed=speed, pitch_correct=pitch_correct)
         config.clamp()
         return (
@@ -160,8 +70,5 @@ class SpeedEngine:
         clip_config: dict,
         global_speed: float = DEFAULT_SPEED,
     ) -> float:
-        """从 clip config 中解析 playback_speed，0 或缺失则使用全局速度。"""
-        speed = clip_config.get("playback_speed", 0) if clip_config else 0
-        if not isinstance(speed, (int, float)) or speed <= 0:
-            return global_speed
-        return float(speed)
+        """从 clip config 中解析 playback_speed，0 或缺失则使用全局速度."""
+        return _resolve_clip_speed_base(clip_config, global_speed)
diff --git a/packages/domain/speed_config.py b/packages/domain/speed_config.py
new file mode 100755
index 000000000..955facc1a
--- /dev/null
+++ b/packages/domain/speed_config.py
@@ -0,0 +1,179 @@
+"""调速配置领域模型 — 纯逻辑，无FFmpeg依赖.
+
+抽离自 speed_engine.py，包含：
+- SpeedConfig 数据类（解析/钳制/原速判断）
+- 视频/音频调速滤镜构建
+- atempo 多级拆分算法
+- 时长计算
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any
+
+# ─── 常量 ───────────────────────────────────────────────
+MIN_SPEED = 0.25
+MAX_SPEED = 4.0
+DEFAULT_SPEED = 1.0
+
+# atempo 单级有效范围
+_ATEMPO_MIN = 0.5
+_ATEMPO_MAX = 2.0
+
+
+@dataclass
+class SpeedConfig:
+    """调速配置.
+
+    Attributes:
+        speed: 播放速度，0.25~4.0，1.0 为原速
+        pitch_correct: 是否保持音调（默认 True，用 atempo 时间拉伸算法）
+    """
+
+    speed: float = DEFAULT_SPEED
+    pitch_correct: bool = True
+
+    @classmethod
+    def parse(cls, data: dict[str, Any] | None) -> SpeedConfig:
+        """从 dict 解析配置，无效值回退到默认."""
+        if not data or not isinstance(data, dict):
+            return cls()
+
+        speed = data.get("speed", DEFAULT_SPEED)
+        if not isinstance(speed, (int, float)):
+            speed = DEFAULT_SPEED
+
+        pitch_correct = data.get("pitch_correct", True)
+        if not isinstance(pitch_correct, bool):
+            pitch_correct = True
+
+        config = cls(speed=float(speed), pitch_correct=pitch_correct)
+        config.clamp()
+        return config
+
+    def clamp(self) -> None:
+        """将速度钳制到合法范围."""
+        if self.speed <= 0:
+            self.speed = DEFAULT_SPEED
+        elif self.speed < MIN_SPEED:
+            self.speed = MIN_SPEED
+        elif self.speed > MAX_SPEED:
+            self.speed = MAX_SPEED
+
+    @property
+    def is_original(self) -> bool:
+        """是否原速（无需调速）."""
+        return abs(self.speed - 1.0) < 1e-6
+
+    @property
+    def is_fast(self) -> bool:
+        """是否加速播放."""
+        return self.speed > 1.0
+
+    @property
+    def is_slow(self) -> bool:
+        """是否减速播放."""
+        return self.speed < 1.0
+
+
+# ── 滤镜构建 ────────────────────────────────────────────────────────────────
+
+
+def build_video_filter(config: SpeedConfig) -> str:
+    """生成视频调速滤镜字符串.
+
+    返回 setpts 滤镜表达式，原速时返回空字符串。
+    """
+    if config.is_original:
+        return ""
+    # setpts=PTS/speed — speed>1 加速，speed<1 减速
+    return f"setpts=PTS/{config.speed:.4f}"
+
+
+def build_audio_filter(config: SpeedConfig) -> str:
+    """生成音频调速滤镜字符串.
+
+    atempo 单级范围 0.5~2.0，超出范围时自动多级串联：
+    - 0.25x → atempo=0.5,atempo=0.5
+    - 4x → atempo=2.0,atempo=2.0
+    - 0.3x → atempo=0.5,atempo=0.6
+    - 3x → atempo=2.0,atempo=1.5
+
+    原速时返回空字符串。
+    """
+    if config.is_original:
+        return ""
+
+    speed = config.speed
+    stages: list[float] = _split_atempo_stages(speed)
+    return ",".join(f"atempo={s:.4f}" for s in stages)
+
+
+def _split_atempo_stages(speed: float) -> list[float]:
+    """将速度拆分为多级 atempo 串联，每级都在 [0.5, 2.0] 范围内."""
+    if _ATEMPO_MIN <= speed <= _ATEMPO_MAX:
+        return [speed]
+
+    stages: list[float] = []
+    remaining = speed
+
+    # 加速场景（speed > 2.0）
+    if speed > _ATEMPO_MAX:
+        while remaining > _ATEMPO_MAX:
+            stages.append(_ATEMPO_MAX)
+            remaining /= _ATEMPO_MAX
+        stages.append(remaining)
+
+    # 减速场景（speed < 0.5）
+    else:
+        while remaining < _ATEMPO_MIN:
+            stages.append(_ATEMPO_MIN)
+            remaining /= _ATEMPO_MIN
+        stages.append(remaining)
+
+    return stages
+
+
+# ── 时长计算 ────────────────────────────────────────────────────────────────
+
+
+def adjust_duration(original_duration: float, config: SpeedConfig) -> float:
+    """计算调速后的时长.
+
+    加速 → 时长变短；减速 → 时长变长。
+    """
+    if config.is_original or original_duration <= 0:
+        return original_duration
+    return original_duration / config.speed
+
+
+# ── 便捷方法 ────────────────────────────────────────────────────────────────
+
+
+def build_clip_speed_filter(
+    speed: float,
+    pitch_correct: bool = True,
+) -> tuple[str, str, SpeedConfig]:
+    """便捷方法：从单一 speed 值生成视频+音频滤镜.
+
+    返回 (video_filter, audio_filter, config)。
+    """
+    config = SpeedConfig(speed=speed, pitch_correct=pitch_correct)
+    config.clamp()
+    return (
+        build_video_filter(config),
+        build_audio_filter(config),
+        config,
+    )
+
+
+def resolve_clip_speed(
+    clip_config: dict[str, Any] | None,
+    global_speed: float = DEFAULT_SPEED,
+) -> float:
+    """从 clip config 中解析 playback_speed，0 或缺失则使用全局速度."""
+    speed = clip_config.get("playback_speed", 0) if clip_config else 0
+    if not isinstance(speed, (int, float)) or speed <= 0:
+        return global_speed
+    return float(speed)
diff --git a/tests/unit/test_speed_config.py b/tests/unit/test_speed_config.py
new file mode 100755
index 000000000..a5480a621
--- /dev/null
+++ b/tests/unit/test_speed_config.py
@@ -0,0 +1,313 @@
+"""speed_config 领域模型单测."""
+
+from __future__ import annotations
+
+import pytest
+
+from packages.domain.speed_config import (
+    DEFAULT_SPEED,
+    MAX_SPEED,
+    MIN_SPEED,
+    SpeedConfig,
+    adjust_duration,
+    build_audio_filter,
+    build_video_filter,
+    build_clip_speed_filter,
+    resolve_clip_speed,
+)
+
+# ── 常量测试 ────────────────────────────────────────────────────────────────
+
+
+class TestConstants:
+    def test_min_speed(self):
+        assert MIN_SPEED == 0.25
+
+    def test_max_speed(self):
+        assert MAX_SPEED == 4.0
+
+    def test_default_speed(self):
+        assert DEFAULT_SPEED == 1.0
+
+
+# ── SpeedConfig.parse 测试 ────────────────────────────────────────────────
+
+
+class TestSpeedConfigParse:
+    def test_none_returns_default(self):
+        cfg = SpeedConfig.parse(None)
+        assert cfg.speed == DEFAULT_SPEED
+        assert cfg.pitch_correct is True
+
+    def test_empty_dict_returns_default(self):
+        cfg = SpeedConfig.parse({})
+        assert cfg.speed == DEFAULT_SPEED
+
+    def test_invalid_type_returns_default(self):
+        cfg = SpeedConfig.parse("not_a_dict")
+        assert cfg.speed == DEFAULT_SPEED
+
+    def test_valid_speed(self):
+        cfg = SpeedConfig.parse({"speed": 2.0})
+        assert cfg.speed == 2.0
+
+    def test_speed_clamped_low(self):
+        cfg = SpeedConfig.parse({"speed": 0.1})
+        assert cfg.speed == MIN_SPEED
+
+    def test_speed_clamped_high(self):
+        cfg = SpeedConfig.parse({"speed": 5.0})
+        assert cfg.speed == MAX_SPEED
+
+    def test_zero_speed_returns_default(self):
+        cfg = SpeedConfig.parse({"speed": 0})
+        assert cfg.speed == DEFAULT_SPEED
+
+    def test_negative_speed_returns_default(self):
+        cfg = SpeedConfig.parse({"speed": -1.0})
+        assert cfg.speed == DEFAULT_SPEED
+
+    def test_pitch_correct_false(self):
+        cfg = SpeedConfig.parse({"pitch_correct": False})
+        assert cfg.pitch_correct is False
+
+    def test_pitch_correct_invalid_type_defaults_true(self):
+        cfg = SpeedConfig.parse({"pitch_correct": "yes"})
+        assert cfg.pitch_correct is True
+
+    def test_string_speed_invalid_uses_default(self):
+        cfg = SpeedConfig.parse({"speed": "fast"})
+        assert cfg.speed == DEFAULT_SPEED
+
+
+# ── SpeedConfig.clamp 测试 ────────────────────────────────────────────────
+
+
+class TestClamp:
+    def test_already_valid_unchanged(self):
+        cfg = SpeedConfig(speed=1.5)
+        cfg.clamp()
+        assert cfg.speed == 1.5
+
+    def test_below_min_clamped(self):
+        cfg = SpeedConfig(speed=0.1)
+        cfg.clamp()
+        assert cfg.speed == MIN_SPEED
+
+    def test_above_max_clamped(self):
+        cfg = SpeedConfig(speed=10.0)
+        cfg.clamp()
+        assert cfg.speed == MAX_SPEED
+
+    def test_zero_defaults(self):
+        cfg = SpeedConfig(speed=0.0)
+        cfg.clamp()
+        assert cfg.speed == DEFAULT_SPEED
+
+    def test_negative_defaults(self):
+        cfg = SpeedConfig(speed=-2.0)
+        cfg.clamp()
+        assert cfg.speed == DEFAULT_SPEED
+
+    def test_exact_min_stays(self):
+        cfg = SpeedConfig(speed=MIN_SPEED)
+        cfg.clamp()
+        assert cfg.speed == MIN_SPEED
+
+    def test_exact_max_stays(self):
+        cfg = SpeedConfig(speed=MAX_SPEED)
+        cfg.clamp()
+        assert cfg.speed == MAX_SPEED
+
+
+# ── is_original / is_fast / is_slow 测试 ─────────────────────────────────
+
+
+class TestSpeedProperties:
+    def test_is_original_true(self):
+        cfg = SpeedConfig(speed=1.0)
+        assert cfg.is_original is True
+
+    def test_is_original_false_fast(self):
+        cfg = SpeedConfig(speed=2.0)
+        assert cfg.is_original is False
+
+    def test_is_original_false_slow(self):
+        cfg = SpeedConfig(speed=0.5)
+        assert cfg.is_original is False
+
+    def test_is_original_near_one(self):
+        cfg = SpeedConfig(speed=1.0000001)
+        assert cfg.is_original is True
+
+    def test_is_fast_true(self):
+        cfg = SpeedConfig(speed=2.0)
+        assert cfg.is_fast is True
+
+    def test_is_fast_false(self):
+        cfg = SpeedConfig(speed=0.5)
+        assert cfg.is_fast is False
+
+    def test_is_false_for_original(self):
+        cfg = SpeedConfig(speed=1.0)
+        assert cfg.is_fast is False
+        assert cfg.is_slow is False
+
+    def test_is_slow_true(self):
+        cfg = SpeedConfig(speed=0.5)
+        assert cfg.is_slow is True
+
+    def test_is_slow_false(self):
+        cfg = SpeedConfig(speed=2.0)
+        assert cfg.is_slow is False
+
+
+# ── build_video_filter 测试 ───────────────────────────────────────────────
+
+
+class TestBuildVideoFilter:
+    def test_original_speed_empty(self):
+        cfg = SpeedConfig(speed=1.0)
+        assert build_video_filter(cfg) == ""
+
+    def test_fast_speed_setpts(self):
+        cfg = SpeedConfig(speed=2.0)
+        result = build_video_filter(cfg)
+        assert "setpts=PTS/2.0000" in result
+
+    def test_slow_speed_setpts(self):
+        cfg = SpeedConfig(speed=0.5)
+        result = build_video_filter(cfg)
+        assert "setpts=PTS/0.5000" in result
+
+    def test_format_four_decimals(self):
+        cfg = SpeedConfig(speed=1.5)
+        result = build_video_filter(cfg)
+        assert "1.5000" in result
+
+
+# ── build_audio_filter 测试 ───────────────────────────────────────────────
+
+
+class TestBuildAudioFilter:
+    def test_original_speed_empty(self):
+        cfg = SpeedConfig(speed=1.0)
+        assert build_audio_filter(cfg) == ""
+
+    def test_single_stage_within_range(self):
+        cfg = SpeedConfig(speed=1.5)
+        result = build_audio_filter(cfg)
+        assert result == "atempo=1.5000"
+        assert result.count("atempo") == 1
+
+    def test_fast_two_stages(self):
+        cfg = SpeedConfig(speed=3.0)
+        result = build_audio_filter(cfg)
+        assert result.count("atempo") == 2
+        # 2.0 * 1.5 = 3.0
+        assert "atempo=2.0000" in result
+        assert "atempo=1.5000" in result
+
+    def test_max_speed_two_stages(self):
+        cfg = SpeedConfig(speed=4.0)
+        result = build_audio_filter(cfg)
+        assert result.count("atempo") == 2
+        # 2.0 * 2.0 = 4.0
+        assert result == "atempo=2.0000,atempo=2.0000"
+
+    def test_slow_two_stages(self):
+        cfg = SpeedConfig(speed=0.25)
+        result = build_audio_filter(cfg)
+        assert result.count("atempo") == 2
+        # 0.5 * 0.5 = 0.25
+        assert result == "atempo=0.5000,atempo=0.5000"
+
+    def test_slow_single_stage(self):
+        cfg = SpeedConfig(speed=0.8)
+        result = build_audio_filter(cfg)
+        assert result == "atempo=0.8000"
+        assert result.count("atempo") == 1
+
+    def test_exactly_two_point_zero_single(self):
+        cfg = SpeedConfig(speed=2.0)
+        result = build_audio_filter(cfg)
+        assert result.count("atempo") == 1
+        assert "atempo=2.0000" in result
+
+    def test_exactly_half_single(self):
+        cfg = SpeedConfig(speed=0.5)
+        result = build_audio_filter(cfg)
+        assert result.count("atempo") == 1
+        assert "atempo=0.5000" in result
+
+
+# ── adjust_duration 测试 ──────────────────────────────────────────────────
+
+
+class TestAdjustDuration:
+    def test_original_speed_unchanged(self):
+        cfg = SpeedConfig(speed=1.0)
+        assert adjust_duration(10.0, cfg) == 10.0
+
+    def test_double_speed_halved(self):
+        cfg = SpeedConfig(speed=2.0)
+        assert adjust_duration(10.0, cfg) == 5.0
+
+    def test_half_speed_doubled(self):
+        cfg = SpeedConfig(speed=0.5)
+        assert adjust_duration(10.0, cfg) == 20.0
+
+    def test_zero_duration_unchanged(self):
+        cfg = SpeedConfig(speed=2.0)
+        assert adjust_duration(0.0, cfg) == 0.0
+
+    def test_negative_duration_unchanged(self):
+        cfg = SpeedConfig(speed=2.0)
+        assert adjust_duration(-5.0, cfg) == -5.0
+
+
+# ── build_clip_speed_filter 测试 ─────────────────────────────────────────
+
+
+class TestBuildClipSpeedFilter:
+    def test_normal_speed(self):
+        vf, af, cfg = build_clip_speed_filter(2.0)
+        assert vf == "setpts=PTS/2.0000"
+        assert "atempo=2.0000" in af
+        assert cfg.speed == 2.0
+
+    def test_clamped_speed(self):
+        vf, af, cfg = build_clip_speed_filter(10.0)
+        assert cfg.speed == MAX_SPEED
+
+    def test_pitch_correct_param(self):
+        vf, af, cfg = build_clip_speed_filter(1.5, pitch_correct=False)
+        assert cfg.pitch_correct is False
+
+    def test_original_speed_empty_filters(self):
+        vf, af, cfg = build_clip_speed_filter(1.0)
+        assert vf == ""
+        assert af == ""
+
+
+# ── resolve_clip_speed 测试 ──────────────────────────────────────────────
+
+
+class TestResolveClipSpeed:
+    def test_none_config_uses_global(self):
+        assert resolve_clip_speed(None, 1.5) == 1.5
+
+    def test_no_playback_speed_uses_global(self):
+        assert resolve_clip_speed({}, 1.5) == 1.5
+
+    def test_zero_speed_uses_global(self):
+        assert resolve_clip_speed({"playback_speed": 0}, 1.5) == 1.5
+
+    def test_valid_speed_returns_speed(self):
+        assert resolve_clip_speed({"playback_speed": 2.0}, 1.0) == 2.0
+
+    def test_invalid_type_uses_global(self):
+        assert resolve_clip_speed({"playback_speed": "fast"}, 1.0) == 1.0
+
+    def test_default_global_speed(self):
+        assert resolve_clip_speed({}) == DEFAULT_SPEED