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