CI Bot
276 lines
9.9 KiB
Python
Executable File
276 lines
9.9 KiB
Python
Executable File
"""字幕生成器 — 将字幕时间轴转换为 ASS 字幕文件。
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与 render_subtitles.py 的区别：
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- render_subtitles.py 处理静态整段标题/字幕
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- 本模块处理带时间轴的多段 ASR 字幕
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两者最终都输出 ASS 文件，供 FFmpeg 烧录。
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"""
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from __future__ import annotations
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import logging
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from pathlib import Path
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from typing import Any
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from packages.domain.ass_subtitle_builder import (
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TITLE_MARGIN_SIDE,
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TITLE_MARGIN_TOP,
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_scale_len,
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_wrap_title_text,
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build_ass_style,
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escape_ass_text,
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format_ass_time,
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hex_to_ass_color,
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position_to_ass_alignment,
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)
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from packages.domain.subtitle import SubtitleTimeline
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logger = logging.getLogger(__name__)
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# ── 常量 ──────────────────────────────────────────────────────────────────────
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DEFAULT_MAX_CHARS_PER_LINE = 20 # 每行最多字符数
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DEFAULT_MIN_CHARS_PER_SEGMENT = 8 # 每段最少字符数
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# ── ASS 工具函数 ────────────────────────────────────────────────────────────
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def _hex_to_ass_color(hex_color: str) -> str:
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"""将 HEX 颜色（#RRGGBB）转换为 ASS &HBBGGRR 格式。"""
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hex_color = hex_color.lstrip("#")
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if len(hex_color) != 6:
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return "&H00FFFFFF"
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r, g, b = hex_color[0:2], hex_color[2:4], hex_color[4:6]
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return f"&H{b.upper()}{g.upper()}{r.upper()}"
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def _position_to_ass_alignment(position: str) -> int:
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"""将文字位置映射为 ASS \\an 对齐编号。"""
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mapping = {
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"top": 8,
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"center": 5,
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"bottom": 2,
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}
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return mapping.get(position, 2)
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def _format_ass_time(seconds: float) -> str:
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"""将秒数格式化为 ASS 时间格式 H:MM:SS.cc。"""
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hours = int(seconds // 3600)
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minutes = int((seconds % 3600) // 60)
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secs = seconds % 60
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return f"{hours}:{minutes:02d}:{secs:05.2f}"
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def _escape_ass_text(text: str) -> str:
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"""转义 ASS 文本中的特殊字符。"""
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text = text.replace("\r\n", "\\N").replace("\n", "\\N").replace("\r", "\\N")
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text = text.replace("{", "(").replace("}", ")")
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return text
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def _wrap_text(text: str, max_chars: int) -> list[str]:
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"""将长文本按字数换行。
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优先在标点处换行，没有合适标点时硬切。
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"""
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if len(text) <= max_chars:
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return [text]
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lines: list[str] = []
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remaining = text
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while len(remaining) > max_chars:
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# 在前 max_chars 个字符中找标点断开
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break_point = max_chars
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punctuations = "，。！？、；：,.;:!?"
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for i in range(max_chars, max_chars // 2, -1):
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if i < len(remaining) and remaining[i] in punctuations:
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break_point = i + 1
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break
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lines.append(remaining[:break_point])
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remaining = remaining[break_point:]
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if remaining:
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lines.append(remaining)
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return lines
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# ── 主生成器 ─────────────────────────────────────────────────────────────────
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def generate_ass_from_timeline(
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output_path: Path,
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timeline: SubtitleTimeline,
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*,
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video_width: int,
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video_height: int,
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video_duration: float = 0.0,
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subtitle_config: dict[str, Any] | None = None,
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title_text: str = "",
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title_config: dict[str, Any] | None = None,
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) -> Path:
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"""从字幕时间轴生成 ASS 字幕文件。
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Args:
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output_path: 输出 ASS 文件路径
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timeline: 字幕时间轴
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video_width: 视频宽度
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video_height: 视频高度
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subtitle_config: 字幕样式配置（同 SubtitleConfig dict）
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Returns:
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生成的 ASS 文件路径
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"""
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subtitle_config = subtitle_config or {}
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if not timeline.segments:
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output_path.write_text("", encoding="utf-8")
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return output_path
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# 样式参数（字号/描边/边距按视频宽度缩放，基准 720p，与前端预览一致）
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_sw = video_width
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font_name = subtitle_config.get("font", "思源黑体")
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font_size = _scale_len(int(subtitle_config.get("size", 24)), _sw)
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color = _hex_to_ass_color(subtitle_config.get("color", "#ffffff"))
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position = subtitle_config.get("position", "bottom")
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alignment = _position_to_ass_alignment(position)
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max_chars_per_line = int(subtitle_config.get("max_chars_per_line", DEFAULT_MAX_CHARS_PER_LINE))
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# 描边（默认黑色描边，保证可读性）—— 720p 基准 1.5
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outline_color = "&H00000000"
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outline_width = _scale_len(1.5, _sw)
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# 边距（720p 基准 60/40）
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margin_v = _scale_len(60 if position == "bottom" else 60, _sw)
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margin_l = _scale_len(40, _sw)
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margin_r = _scale_len(40, _sw)
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# 生成样式行
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style_line = (
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f"Style: Default,{font_name},{font_size},{color},"
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f"&H000000FF,{outline_color},&H00000000,"
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f"-1,0,0,0,100,100,0,0,"
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f"1,{outline_width},0,{alignment},"
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f"{margin_l},{margin_r},{margin_v},1"
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)
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# 生成事件行
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events: list[str] = []
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for seg in timeline.segments:
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start_time = _format_ass_time(seg.start)
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end_time = _format_ass_time(seg.end)
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# 自动换行
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lines = _wrap_text(seg.text, max_chars_per_line)
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display_text = "\\N".join(lines)
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safe_text = _escape_ass_text(display_text)
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events.append(f"Dialogue: 0,{start_time},{end_time},Default,,0,0,0,,{safe_text}")
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# ── 标题样式与事件（叠加在 ASR 字幕之上）───────────────────────────
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title_cfg = title_config or {}
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if not isinstance(title_cfg, dict):
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title_cfg = {}
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title_enabled = title_cfg.get("enabled", True) and bool(title_text.strip())
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title_style_line = ""
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title_event_line = ""
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if title_enabled:
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# 兼容 boolean stroke/shadow → dict
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_stroke_val = title_cfg.get("stroke")
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if isinstance(_stroke_val, bool):
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title_cfg["stroke"] = (
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{"enabled": _stroke_val, "color": "#000000", "width": 2} if _stroke_val else {"enabled": False}
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)
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_shadow_val = title_cfg.get("shadow")
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if isinstance(_shadow_val, bool):
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title_cfg["shadow"] = (
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{"enabled": _shadow_val, "color": "#000000", "blur": 4, "offset_x": 2, "offset_y": 2}
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if _shadow_val
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else {"enabled": False}
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)
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# 字段名归一化: font_size→size, font_color→color
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if "font_size" in title_cfg and "size" not in title_cfg:
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title_cfg["size"] = title_cfg["font_size"]
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if "font_color" in title_cfg and "color" not in title_cfg:
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title_cfg["color"] = title_cfg["font_color"]
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_tsw = video_width
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t_color = hex_to_ass_color(title_cfg.get("color", "#ffffff"))
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t_stroke = title_cfg.get("stroke", {}) or {}
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t_shadow = title_cfg.get("shadow", {}) or {}
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s_color = hex_to_ass_color(t_stroke.get("color", "#000000"))
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s_width = _scale_len(float(t_stroke.get("width", 2)) if t_stroke.get("enabled", False) else 0.0, _tsw)
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sh_blur = _scale_len(float(t_shadow.get("blur", 4)) if t_shadow.get("enabled", False) else 0.0, _tsw)
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sh_offset = (
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_scale_len(t_shadow.get("offset_x", 2) if t_shadow.get("enabled", False) else 0, _tsw),
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_scale_len(t_shadow.get("offset_y", 2) if t_shadow.get("enabled", False) else 0, _tsw),
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)
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t_alignment = position_to_ass_alignment(title_cfg.get("position", "bottom"))
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# 标题字号/边距按视频宽度缩放（基准 720p），移除旧的 min(...,36) 上限避免 1080p 被钳位过小
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_base_title_size = int(title_cfg.get("size", 36))
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t_font_size = _scale_len(_base_title_size, _tsw)
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_t_margin_top = _scale_len(TITLE_MARGIN_TOP, _tsw)
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_t_margin_side = _scale_len(TITLE_MARGIN_SIDE, _tsw)
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title_style_line = build_ass_style(
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"TitleStyle",
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font_name=title_cfg.get("font", "思源黑体"),
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font_size=t_font_size,
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primary_color=t_color,
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outline_color=s_color,
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outline_width=s_width,
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shadow_blur=sh_blur,
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shadow_offset=sh_offset,
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bold=bool(title_cfg.get("bold", True)),
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italic=bool(title_cfg.get("italic", False)),
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alignment=t_alignment,
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margin_v=_t_margin_top,
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margin_l=_t_margin_side,
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margin_r=_t_margin_side,
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)
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safe_raw = escape_ass_text(title_text.strip())
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safe_wrapped = _wrap_title_text(
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safe_raw, video_width, t_font_size, margin_l=_t_margin_side, margin_r=_t_margin_side
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)
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if video_duration > 0:
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t_end_time = format_ass_time(video_duration)
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else:
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t_end_time = format_ass_time((timeline.segments[-1].end + 5.0) if timeline.segments else 60.0)
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title_event_line = f"Dialogue: 0,0:00:00.00,{t_end_time},TitleStyle,,0,0,0,,{safe_wrapped}"
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# 组装 ASS 文件
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ass_content = f"""[Script Info]
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ScriptType: v4.00+
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PlayResX: {video_width}
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PlayResY: {video_height}
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ScaledBorderAndShadow: yes
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WrapStyle: 2
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Encoding: UTF-8
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[V4+ Styles]
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Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding # noqa: E501
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{chr(10).join(filter(None, [title_style_line, style_line]))}
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[Events]
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Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
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{chr(10).join(filter(None, [title_event_line] + events))}
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"""
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output_path.parent.mkdir(parents=True, exist_ok=True)
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output_path.write_text(ass_content, encoding="utf-8")
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return output_path
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