alembic/versions/083_cover_title_config.py

@@ -0,0 +1,26 @@
+"""#2001 爆款标题样式面板升级: ai_avatar_render_jobs 新增 cover_title_config
+
+Revision ID: 083_cover_title_config
+Revises: 082_atom_clip_ai_tags
+Create Date: 2026-09-20
+"""
+
+import sqlalchemy as sa
+
+from alembic import op
+
+revision = "083_cover_title_config"
+down_revision = "082_atom_clip_ai_tags"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "ai_avatar_render_jobs",
+        sa.Column("cover_title_config", sa.JSON(), nullable=False, server_default=sa.text("'{}'")),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("ai_avatar_render_jobs", "cover_title_config")

apps/api/app/api/routes/ai_avatar_render.py

@@ -63,6 +63,7 @@ def create_render_job(
             b_roll_segments=[s.model_dump() for s in body.b_roll_segments],
             title_config=body.title_config,
             cover_config=body.cover_config,
+            cover_title_config=body.cover_title_config,
             project_id=body.project_id,
         )
     except AiAvatarRenderError as exc:

apps/api/app/schemas/ai_avatar_render.py

@@ -53,9 +53,14 @@ class CreateAiAvatarRenderRequest(BaseModel):
     script_id: str = Field("", description="文案 ID（选自文案库时传；手动输入文案直生场景可留空）")
     b_roll_segments: list[BRollSegment] = Field(default_factory=list, description="B-roll 片段列表")
     title_config: dict[str, Any] = Field(
-        default_factory=dict, description="标题配置（可含 title_image_dataurl：前端 Canvas 渲染的标题 PNG dataURL）"
+        default_factory=dict,
+        description="标题配置（可含 title_image_dataurl：前端 Canvas 渲染的标题 PNG dataURL；含 line_overrides 逐行样式）",
     )
     cover_config: dict[str, Any] = Field(default_factory=dict, description="封面配置")
+    cover_title_config: dict[str, Any] = Field(
+        default_factory=dict,
+        description="封面独立标题配置（#2001），结构同 title_config；为空时封面不叠标题",
+    )
     project_id: str = Field("", description="项目 ID")
 
     @field_validator("lipsync_job_id")
@@ -83,6 +88,7 @@ class AiAvatarRenderJobResponse(BaseModel):
     b_roll_segments: list[dict[str, Any]]
     title_config: dict[str, Any]
     cover_config: dict[str, Any]
+    cover_title_config: dict[str, Any] = Field(default_factory=dict, description="封面独立标题配置")
     status: str
     progress: int
     output_video_url: str

apps/api/app/services/ai_avatar_render_service.py

@@ -61,6 +61,7 @@ class AiAvatarRenderService:
         b_roll_segments: list[dict[str, Any]] | None = None,
         title_config: dict[str, Any],
         cover_config: dict[str, Any],
+        cover_title_config: dict[str, Any] | None = None,
         project_id: str = "",
     ) -> AiAvatarRenderJob:
         """创建渲染任务.
@@ -112,6 +113,7 @@ class AiAvatarRenderService:
             b_roll_segments=[s if isinstance(s, dict) else s.model_dump() for s in (b_roll_segments or [])],
             title_config=title_config,
             cover_config=cover_config,
+            cover_title_config=cover_title_config or {},
             status="pending",
         )
         self.db.add(job)

infra/docker/api-base.Dockerfile

@@ -31,6 +31,12 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY infra/fonts/NotoSansSC-VF.ttf /usr/share/fonts/opentype/noto/NotoSansSC-VF.ttf
 COPY infra/fonts/NotoSerifCJKsc-VF.otf /usr/share/fonts/opentype/noto/NotoSerifCJKsc-VF.otf
 COPY infra/fonts/LXGWWenKai-Regular.ttf /usr/share/fonts/truetype/lxgw/LXGWWenKai-Regular.ttf
+# #2001 爆款标题字体：优设标题黑 / 阿里普惠体 Bold / 抖音美好体 / 思源黑体 Heavy
+RUN mkdir -p /usr/share/fonts/truetype/xiaoxia
+COPY infra/fonts/xiaoxia/YouSheBiaoTiHei.ttf /usr/share/fonts/truetype/xiaoxia/YouSheBiaoTiHei.ttf
+COPY infra/fonts/xiaoxia/AlibabaPuHuiTi-Bold.ttf /usr/share/fonts/truetype/xiaoxia/AlibabaPuHuiTi-Bold.ttf
+COPY infra/fonts/xiaoxia/DouyinSansBold.otf /usr/share/fonts/truetype/xiaoxia/DouyinSansBold.otf
+COPY infra/fonts/xiaoxia/NotoSansSC-Black.otf /usr/share/fonts/truetype/xiaoxia/NotoSansSC-Black.otf
 RUN fc-cache -fv
 
 # 创建虚拟环境

infra/docker/worker-base.Dockerfile

@@ -35,6 +35,12 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY infra/fonts/NotoSansSC-VF.ttf /usr/share/fonts/opentype/noto/NotoSansSC-VF.ttf
 COPY infra/fonts/NotoSerifCJKsc-VF.otf /usr/share/fonts/opentype/noto/NotoSerifCJKsc-VF.otf
 COPY infra/fonts/LXGWWenKai-Regular.ttf /usr/share/fonts/truetype/lxgw/LXGWWenKai-Regular.ttf
+# #2001 爆款标题字体：优设标题黑 / 阿里普惠体 Bold / 抖音美好体 / 思源黑体 Heavy
+RUN mkdir -p /usr/share/fonts/truetype/xiaoxia
+COPY infra/fonts/xiaoxia/YouSheBiaoTiHei.ttf /usr/share/fonts/truetype/xiaoxia/YouSheBiaoTiHei.ttf
+COPY infra/fonts/xiaoxia/AlibabaPuHuiTi-Bold.ttf /usr/share/fonts/truetype/xiaoxia/AlibabaPuHuiTi-Bold.ttf
+COPY infra/fonts/xiaoxia/DouyinSansBold.otf /usr/share/fonts/truetype/xiaoxia/DouyinSansBold.otf
+COPY infra/fonts/xiaoxia/NotoSansSC-Black.otf /usr/share/fonts/truetype/xiaoxia/NotoSansSC-Black.otf
 RUN fc-cache -fv
 
 # 创建虚拟环境

packages/adapters/sqlalchemy_impl/models.py

@@ -750,6 +750,8 @@ class AiAvatarRenderJob(Base):
     # b_roll_segments 格式: [{"script_segment_index": 0, "asset_url": "...", "mode": "fullscreen|pip", "start_time": 5.0, "end_time": 10.0}, ...]
     title_config = Column(JSON, nullable=False, default=dict)
     cover_config = Column(JSON, nullable=False, default=dict)
+    # #2001 封面独立标题配置（结构同 title_config；为空时封面不叠标题）
+    cover_title_config = Column(JSON, nullable=False, default=dict)
 
     # 任务状态
     status = Column(String(20), nullable=False, default="pending", index=True)

packages/domain/ass_subtitle_builder.py

@@ -30,6 +30,8 @@ TITLE_MARGIN_SIDE = 40
 # - 楷体 → LXGW WenKai（霞鹜文楷，#1896 新增 SIL OFL 开源楷体）
 # - 苹方/PingFang/微软雅黑：服务器 Linux 无对应字体，fallback 思源黑体
 # - 华康俪金黑：商业字体有版权风险，前端已移除，后端保留映射 fallback 思源黑体（兼容老数据）
+# #2001 爆款标题字体（部署到 /usr/share/fonts/truetype/xiaoxia/）：
+# - 优设标题黑 / 阿里普惠体 Bold / 抖音美好体 / 思源黑体 Heavy（独立 Black 字重）
 FONT_NAME_MAP: dict[str, str] = {
     "思源黑体": "Noto Sans SC",
     "思源宋体": "Noto Serif CJK SC",
@@ -40,6 +42,15 @@ FONT_NAME_MAP: dict[str, str] = {
     "楷体": "LXGW WenKai",
     "霞鹜文楷": "LXGW WenKai",
     "华康俪金黑": "Noto Sans SC",
+    # #2001 爆款标题字体
+    "优设标题黑": "YouSheBiaoTiHei",
+    "阿里普惠体": "Alibaba PuHuiTi",
+    "阿里普惠体 Bold": "Alibaba PuHuiTi",
+    "阿里巴巴普惠体": "Alibaba PuHuiTi",
+    "抖音美好体": "Douyin Sans",
+    "抖音体": "Douyin Sans",
+    "思源黑体 Heavy": "Noto Sans SC",
+    "思源黑体 Black": "Noto Sans SC",
 }
 
 # ASS Fontsize 是字体 em-square 高度（含 Latin 升降部留白），
@@ -421,6 +432,14 @@ def build_ass_content(
         safe_title_text_raw = escape_ass_text(title_text)
         safe_title_text = _wrap_title_text(safe_title_text_raw, video_width, title_font_size)
 
+        # #2001 逐行样式覆盖：按 line_overrides 在每行前注入 ASS inline override 标签
+        # line_overrides 透传自前端爆款标题面板，SubtitleStyle.from_dict 已做安全过滤
+        if title_config.get("line_overrides"):
+            from packages.domain.subtitle_style import SubtitleStyle
+
+            _title_style_for_overrides = SubtitleStyle.from_dict(title_config)
+            safe_title_text = _title_style_for_overrides.apply_line_overrides(safe_title_text)
+
         # 自由位置：在文本前注入 \pos override tag（锚点为文本块中心，配合 \an5）
         if title_pos is not None:
             safe_title_text = f"{{\\pos({title_pos[0]},{title_pos[1]})}}{safe_title_text}"
@@ -455,6 +474,13 @@ def build_ass_content(
 
         safe_subtitle_text = escape_ass_text(subtitle_text)
 
+        # #2001 逐行样式覆盖（字幕路径同样支持）
+        if subtitle_config.get("line_overrides"):
+            from packages.domain.subtitle_style import SubtitleStyle
+
+            _sub_style_for_overrides = SubtitleStyle.from_dict(subtitle_config)
+            safe_subtitle_text = _sub_style_for_overrides.apply_line_overrides(safe_subtitle_text)
+
         events.append(
             "Dialogue: 0,0:00:00.00,"
             f"{format_ass_time(video_duration)},"

packages/domain/subtitle_style.py

@@ -6,7 +6,7 @@
 
 from __future__ import annotations
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Any
 
 # ── 常量 ──────────────────────────────────────────────────────────────────────
@@ -163,6 +163,12 @@ class SubtitleStyle:
     fade_out: float = 0.0
     animation_type: str = "none"
 
+    # 逐行独立样式覆盖（#2001 爆款标题样式面板）
+    # list[dict]，每项可选字段: line_index(0-based，支持负数从末尾倒数),
+    # color/font/size/bold/italic/stroke_color/stroke_width/shadow_color/shadow_offset_x/shadow_offset_y
+    # 渲染时按行索引匹配，用 ASS 内联 override 标签包裹该行。缺省字段继承主样式。
+    line_overrides: list[dict[str, Any]] = field(default_factory=list)
+
     @classmethod
     def from_dict(cls, config: dict[str, Any] | None) -> "SubtitleStyle":
         """从字典创建样式配置，带安全类型转换."""
@@ -193,6 +199,14 @@ class SubtitleStyle:
         if position not in POSITION_ALIGNMENT:
             position = DEFAULT_POSITION
 
+        # 逐行覆盖：仅保留 dict 类型项；非 dict 项过滤掉避免渲染崩溃
+        raw_overrides = config.get("line_overrides") or []
+        line_overrides: list[dict[str, Any]] = []
+        if isinstance(raw_overrides, list):
+            for item in raw_overrides:
+                if isinstance(item, dict):
+                    line_overrides.append(dict(item))
+
         return cls(
             font_name=safe_str("font", DEFAULT_FONT),
             font_size=safe_int("size", DEFAULT_FONT_SIZE),
@@ -221,6 +235,7 @@ class SubtitleStyle:
             fade_in=max(0.0, safe_float("fade_in", 0.0)),
             fade_out=max(0.0, safe_float("fade_out", 0.0)),
             animation_type=safe_str("animation_type", "none"),
+            line_overrides=line_overrides,
         )
 
     @property
@@ -248,6 +263,130 @@ class SubtitleStyle:
         color_bgr = hex_to_ass_bgr(self.background_color)
         return f"&H{alpha_hex}{color_bgr}"
 
+    def build_line_override_tag(self, line_index: int, total_lines: int) -> str:
+        r"""按 line_overrides 配置为指定行构造 ASS 内联 override 标签 {\c&HBBGGRR&...}.
+
+        仅返回大括号包裹的 override 标签串；调用方拼到该行文本前即可。
+        未配置该覆盖项时返回空串。缺省字段继承主样式，不生成对应 tag。
+
+        Args:
+            line_index: 行号（0-based）；支持负数（-1 为最后一行）。
+            total_lines: 总行数（用于解析负数索引）。
+        """
+        if not self.line_overrides or total_lines <= 0:
+            return ""
+
+        # 解析负数索引
+        resolved = line_index if line_index >= 0 else total_lines + line_index
+        if resolved < 0 or resolved >= total_lines:
+            return ""
+
+        override: dict[str, Any] | None = None
+        for item in self.line_overrides:
+            if not isinstance(item, dict):
+                continue
+            idx = item.get("line_index")
+            try:
+                idx_int = int(idx) if idx is not None else None
+            except (TypeError, ValueError):
+                continue
+            if idx_int is None:
+                continue
+            if idx_int < 0:
+                idx_int = total_lines + idx_int
+            if idx_int == resolved:
+                override = item
+                break
+
+        if not override:
+            return ""
+
+        tags: list[str] = []
+
+        # 主色（字体颜色）：\c&HBBGGRR&
+        color_val = override.get("color")
+        if isinstance(color_val, str) and color_val:
+            tags.append(f"\\c{hex_to_ass_color(color_val)}")
+
+        # 字号：\fsN
+        size_val = override.get("size") or override.get("font_size")
+        try:
+            size_int = int(size_val) if size_val is not None else None
+            if size_int and size_int > 0:
+                tags.append(f"\\fs{size_int}")
+        except (TypeError, ValueError):
+            pass
+
+        # 字体：\fnFontName
+        font_val = override.get("font") or override.get("font_name")
+        if isinstance(font_val, str) and font_val:
+            tags.append(f"\\fn{font_val}")
+
+        # 粗体：\b1 / \b0
+        bold_val = override.get("bold")
+        if isinstance(bold_val, bool):
+            tags.append("\\b1" if bold_val else "\\b0")
+
+        # 斜体：\i1 / \i0
+        italic_val = override.get("italic")
+        if isinstance(italic_val, bool):
+            tags.append("\\i1" if italic_val else "\\i0")
+
+        # 描边色：\3c&HBBGGRR&
+        stroke_c = override.get("stroke_color")
+        if isinstance(stroke_c, str) and stroke_c:
+            tags.append(f"\\3c{hex_to_ass_color(stroke_c)}")
+
+        # 描边宽：\bordN
+        stroke_w = override.get("stroke_width")
+        try:
+            sw = float(stroke_w) if stroke_w is not None else None
+            if sw is not None and sw >= 0:
+                tags.append(f"\\bord{sw:g}")
+        except (TypeError, ValueError):
+            pass
+
+        # 阴影色：\4c&HBBGGRR&
+        shadow_c = override.get("shadow_color")
+        if isinstance(shadow_c, str) and shadow_c:
+            tags.append(f"\\4c{hex_to_ass_color(shadow_c)}")
+
+        # 阴影偏移：\shadN（单值，同时设置 x/y；精细控制用 \xshad/\yshad）
+        sx = override.get("shadow_offset_x")
+        sy = override.get("shadow_offset_y")
+        try:
+            sx_i = int(sx) if sx is not None else None
+            sy_i = int(sy) if sy is not None else None
+            if sx_i is not None:
+                tags.append(f"\\xshad{sx_i}")
+            if sy_i is not None:
+                tags.append(f"\\yshad{sy_i}")
+        except (TypeError, ValueError):
+            pass
+
+        if not tags:
+            return ""
+        return "{" + "".join(tags) + "}"
+
+    def apply_line_overrides(self, text: str) -> str:
+        """按 line_overrides 对 ASS 文本（已 escape、换行用 \\N 分隔）逐行套 override 标签.
+
+        仅对换行后的每行首加对应 override 标签；无 override 的行保持原样。
+        """
+        if not self.line_overrides or not text:
+            return text
+        if "\\N" not in text:
+            # 单行
+            tag = self.build_line_override_tag(0, 1)
+            return tag + text if tag else text
+        lines = text.split("\\N")
+        total = len(lines)
+        out: list[str] = []
+        for i, ln in enumerate(lines):
+            tag = self.build_line_override_tag(i, total)
+            out.append(tag + ln if tag else ln)
+        return "\\N".join(out)
+
 
 # ── 字幕片段 ──────────────────────────────────────────────────────────────────
 

packages/domain/video_filter_builder.py

@@ -388,6 +388,11 @@ DRAWTEXT_FONT_SEARCH_PATHS: list[str] = [
     "/usr/share/fonts/opentype/noto/NotoSansSC-VF.ttf",
     "/usr/share/fonts/opentype/noto/NotoSerifCJKsc-VF.otf",
     "/usr/share/fonts/truetype/lxgw/LXGWWenKai-Regular.ttf",
+    # #2001 爆款标题字体（优设标题黑 / 阿里普惠体 Bold / 抖音美好体 / 思源黑体 Heavy）
+    "/usr/share/fonts/truetype/xiaoxia/YouSheBiaoTiHei.ttf",
+    "/usr/share/fonts/truetype/xiaoxia/AlibabaPuHuiTi-Bold.ttf",
+    "/usr/share/fonts/truetype/xiaoxia/DouyinSansBold.otf",
+    "/usr/share/fonts/truetype/xiaoxia/NotoSansSC-Black.otf",
     "/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc",
     "/usr/share/fonts/opentype/noto/NotoSansCJK-Bold.ttc",
     "/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc",
@@ -400,6 +405,7 @@ DRAWTEXT_FONT_SEARCH_PATHS: list[str] = [
 # #1896 字体映射修复：每个字体映射到独立的关键字，而非全部回退到 NotoSansSC
 # - 苹方（macOS）/ 微软雅黑（Windows）/ PingFang：服务器 Linux 无对应文件，fallback 思源黑体
 # - 华康俪金黑：商业字体有版权风险，前端已按 #1896 要求移除，后端保留映射但 fallback 思源黑体（兼容老数据）
+# #2001 新增爆款标题字体映射
 DRAWTEXT_FONT_MAP: dict[str, str] = {
     "思源黑体": "NotoSansSC",
     "思源宋体": "NotoSerifCJKsc",
@@ -410,6 +416,15 @@ DRAWTEXT_FONT_MAP: dict[str, str] = {
     "楷体": "LXGWWenKai",
     "霞鹜文楷": "LXGWWenKai",
     "华康俪金黑": "NotoSansSC",
+    # #2001 爆款标题字体
+    "优设标题黑": "YouSheBiaoTiHei",
+    "阿里普惠体": "AlibabaPuHuiTi-Bold",
+    "阿里普惠体 Bold": "AlibabaPuHuiTi-Bold",
+    "阿里巴巴普惠体": "AlibabaPuHuiTi-Bold",
+    "抖音美好体": "DouyinSansBold",
+    "抖音体": "DouyinSansBold",
+    "思源黑体 Heavy": "NotoSansSC-Black",
+    "思源黑体 Black": "NotoSansSC-Black",
 }
 
 

tests/unit/test_ai_avatar_render_routes.py

@@ -50,6 +50,7 @@ def _make_mock_render_job(
     m.b_roll_segments = []
     m.title_config = {}
     m.cover_config = {}
+    m.cover_title_config = {}
     m.status = status
     m.progress = progress
     m.output_video_url = output_video_url
@@ -93,6 +94,7 @@ class TestRenderRoutes:
         body.b_roll_segments = []
         body.title_config = {}
         body.cover_config = {}
+        body.cover_title_config = {}
         body.project_id = ""
 
         result = create_render_job(
@@ -118,6 +120,7 @@ class TestRenderRoutes:
         body.b_roll_segments = []
         body.title_config = {}
         body.cover_config = {}
+        body.cover_title_config = {}
         body.project_id = ""
 
         with pytest.raises(HTTPException) as exc_info:
@@ -141,6 +144,7 @@ class TestRenderRoutes:
         body.b_roll_segments = []
         body.title_config = {}
         body.cover_config = {}
+        body.cover_title_config = {}
         body.project_id = ""
 
         with pytest.raises(HTTPException) as exc_info:

tests/unit/test_lipsync_routes.py

@@ -298,6 +298,7 @@ class TestLipsyncServiceUnit:
 
         mock_db = MagicMock()
         svc = LipsyncService(mock_db, client=mock_mediakit)
+        svc.settings.use_gpu_lipsync = False
 
         with pytest.raises(MediaKitError, match="API 调用失败"):
             svc.create_job(
@@ -473,6 +474,7 @@ class TestLipsyncServiceUnit:
             cosyvoice_service=mock_cosyvoice,
             voice_clone_repo=MagicMock(),
         )
+        svc.settings.use_gpu_lipsync = False
         job = svc.create_job(
             user_id="user-1",
             video_url="https://example.com/video.mp4",
@@ -616,12 +618,14 @@ class TestSignMediaUrl403Fix:
     def _svc(self, mock_mediakit, mock_cosyvoice):
         from app.services.lipsync_service import LipsyncService
 
-        return LipsyncService(
+        svc = LipsyncService(
             MagicMock(),
             client=mock_mediakit,
             cosyvoice_service=mock_cosyvoice,
             voice_clone_repo=MagicMock(),
         )
+        svc.settings.use_gpu_lipsync = False
+        return svc
 
     def test_own_oss_unsigned_url_gets_resigned(self, mock_mediakit, mock_cosyvoice):
         """裸 public_url（不带签名，私有桶匿名 403）必须被重签."""

tests/unit/test_subtitle_style.py

@@ -399,3 +399,226 @@ class TestSubtitleSegment:
     def test_is_valid_zero_duration(self):
         seg = SubtitleSegment(start=1, end=1, text="hello")
         assert seg.is_valid is False
+
+
+# ── line_overrides 逐行样式覆盖测试 ─────────────────────────────────────────
+
+
+class TestBuildLineOverrideTag:
+    def test_empty_overrides_returns_empty(self):
+        style = SubtitleStyle()
+        assert style.build_line_override_tag(0, 1) == ""
+
+    def test_no_matching_line_returns_empty(self):
+        style = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 1, "color": "#FF0000"}]})
+        assert style.build_line_override_tag(0, 2) == ""
+
+    def test_out_of_range_index_returns_empty(self):
+        style = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 5, "color": "#FF0000"}]})
+        assert style.build_line_override_tag(0, 2) == ""
+
+    def test_negative_index_resolves_from_end(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [{"line_index": -1, "color": "#FF0000", "font_size": 48}],
+            }
+        )
+        tag = style.build_line_override_tag(-1, 3)  # last line, 3 lines total
+        assert tag
+        assert "\\c&H000000FF" in tag  # red
+        assert "\\fs48" in tag
+        assert tag.startswith("{") and tag.endswith("}")
+
+    def test_color_override(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [{"line_index": 0, "color": "#00FF00"}],
+            }
+        )
+        tag = style.build_line_override_tag(0, 1)
+        assert "\\c&H0000FF00" in tag  # green = 00FF00 → bgr 00FF00
+
+    def test_font_size_override(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [{"line_index": 0, "font_size": 60}],
+            }
+        )
+        tag = style.build_line_override_tag(0, 1)
+        assert "\\fs60" in tag
+
+    def test_font_override(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [{"line_index": 0, "font": "优设标题黑"}],
+            }
+        )
+        tag = style.build_line_override_tag(0, 1)
+        assert "\\fn优设标题黑" in tag
+
+    def test_bold_on_off(self):
+        style_bold = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0, "bold": True}]})
+        assert "\\b1" in style_bold.build_line_override_tag(0, 1)
+        style_nobold = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0, "bold": False}]})
+        assert "\\b0" in style_nobold.build_line_override_tag(0, 1)
+
+    def test_italic_on_off(self):
+        style_italic = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0, "italic": True}]})
+        assert "\\i1" in style_italic.build_line_override_tag(0, 1)
+        style_noitalic = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0, "italic": False}]})
+        assert "\\i0" in style_noitalic.build_line_override_tag(0, 1)
+
+    def test_stroke_override(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [{"line_index": 0, "stroke_color": "#0000FF", "stroke_width": 3.0}],
+            }
+        )
+        tag = style.build_line_override_tag(0, 1)
+        assert "\\3c&H00FF0000" in tag  # blue bgr
+        assert "\\bord3" in tag
+
+    def test_shadow_override(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [
+                    {"line_index": 0, "shadow_color": "#000000", "shadow_offset_x": 2, "shadow_offset_y": 3}
+                ],
+            }
+        )
+        tag = style.build_line_override_tag(0, 1)
+        assert "\\4c&H00000000" in tag  # black
+        assert "\\xshad2" in tag
+        assert "\\yshad3" in tag
+
+    def test_full_combo(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [
+                    {
+                        "line_index": 0,
+                        "color": "#FF0000",
+                        "font_size": 72,
+                        "font": "抖音美好体",
+                        "bold": True,
+                        "italic": False,
+                        "stroke_color": "#FFFFFF",
+                        "stroke_width": 2,
+                        "shadow_color": "#000000",
+                        "shadow_offset_x": 0,
+                        "shadow_offset_y": 4,
+                    }
+                ],
+            }
+        )
+        tag = style.build_line_override_tag(0, 1)
+        assert "\\c&H000000FF" in tag
+        assert "\\fs72" in tag
+        assert "\\fn抖音美好体" in tag
+        assert "\\b1" in tag
+        assert "\\i0" in tag
+        assert "\\3c&H00FFFFFF" in tag
+        assert "\\bord2" in tag
+        assert "\\4c&H00000000" in tag
+        assert "\\xshad0" in tag
+        assert "\\yshad4" in tag
+
+    def test_empty_override_dict_returns_empty(self):
+        style = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0}]})
+        assert style.build_line_override_tag(0, 1) == ""
+
+    def test_non_dict_items_filtered(self):
+        # 从 dict 解析时已过滤，这里手动构造测试
+        style = SubtitleStyle(line_overrides=["not a dict", {"line_index": 0, "color": "#FF0000"}])
+        tag = style.build_line_override_tag(0, 1)
+        assert "\\c&H000000FF" in tag
+
+    def test_total_lines_zero_returns_empty(self):
+        style = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0, "color": "#FF0000"}]})
+        assert style.build_line_override_tag(0, 0) == ""
+
+    def test_line_index_none_skipped(self):
+        style = SubtitleStyle.from_dict({"line_overrides": [{"color": "#FF0000"}]})  # 无 line_index
+        assert style.build_line_override_tag(0, 1) == ""
+
+
+class TestApplyLineOverrides:
+    def test_empty_text_returns_empty(self):
+        style = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0, "color": "#FF0000"}]})
+        assert style.apply_line_overrides("") == ""
+
+    def test_no_overrides_returns_original(self):
+        style = SubtitleStyle()
+        assert style.apply_line_overrides("hello\\Nworld") == "hello\\Nworld"
+
+    def test_single_line(self):
+        style = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0, "color": "#FF0000", "font_size": 60}]})
+        result = style.apply_line_overrides("单行标题")
+        assert result.startswith("{")
+        assert "单行标题" in result
+        assert "\\c&H000000FF" in result
+
+    def test_multi_line_only_first_line_tagged(self):
+        style = SubtitleStyle.from_dict({"line_overrides": [{"line_index": 0, "color": "#FF0000", "font_size": 72}]})
+        result = style.apply_line_overrides("第一行\\N第二行\\N第三行")
+        lines = result.split("\\N")
+        assert len(lines) == 3
+        assert lines[0].startswith("{\\c&H000000FF")
+        assert "第一行" in lines[0]
+        assert lines[1] == "第二行"  # 无标签
+        assert lines[2] == "第三行"
+
+    def test_multi_line_middle_and_last(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [
+                    {"line_index": 0, "font_size": 72, "bold": True},
+                    {"line_index": -1, "color": "#00FF00", "font_size": 36},
+                ],
+            }
+        )
+        result = style.apply_line_overrides("主标题\\N副标题\\N脚注")
+        lines = result.split("\\N")
+        assert lines[0].startswith("{\\fs72\\b1}")
+        assert lines[1] == "副标题"
+        assert "\\c&H0000FF00" in lines[2]
+        assert "\\fs36" in lines[2]
+
+    def test_line_without_override_kept_verbatim(self):
+        style = SubtitleStyle.from_dict(
+            {
+                "line_overrides": [{"line_index": 1, "bold": True}],
+            }
+        )
+        result = style.apply_line_overrides("第一行\\N第二行")
+        lines = result.split("\\N")
+        assert lines[0] == "第一行"
+        assert lines[1].startswith("{\\b1}")
+        assert "第二行" in lines[1]
+
+
+class TestFromDictLineOverrides:
+    def test_from_dict_parses_line_overrides(self):
+        cfg = {
+            "line_overrides": [
+                {"line_index": 0, "color": "#FF0000", "bold": True},
+                {"line_index": 1, "font_size": 36},
+            ],
+        }
+        style = SubtitleStyle.from_dict(cfg)
+        assert len(style.line_overrides) == 2
+        assert style.line_overrides[0]["line_index"] == 0
+        assert style.line_overrides[1]["font_size"] == 36
+
+    def test_from_dict_filters_non_dict_items(self):
+        cfg = {"line_overrides": [{"line_index": 0, "color": "#FF0000"}, "bad", None, 123]}
+        style = SubtitleStyle.from_dict(cfg)
+        assert len(style.line_overrides) == 1
+
+    def test_from_dict_no_field_defaults_empty(self):
+        style = SubtitleStyle.from_dict({"font": "微软雅黑"})
+        assert style.line_overrides == []
+
+    def test_default_has_empty_list(self):
+        style = SubtitleStyle()
+        assert style.line_overrides == []