Release v1.0.10: shared media_assets and screencast media_assets_root override

Co-authored-by: Cursor <cursoragent@cursor.com>

src/screencast/composer.py

@@ -1,16 +1,18 @@
 """FFmpeg 合成：帧序列 + SRT 字幕 + 背景音乐 → MP4。"""
 from __future__ import annotations
 
-import random
 import subprocess
 import sys
+from dataclasses import dataclass, field
 from pathlib import Path
 
+from jiangchang_skill_core.media_assets import (
+    background_music_issue,
+    pick_background_music,
+    resolve_ffmpeg,
+)
 
 # 匠厂统一字幕样式 —— 所有 skill 录屏共用，做品牌一致性
-# FontSize 14：1080p 屏幕约占 1.3% 高度，演示视频留足画面呼吸感
-# Outline 2：14 号字配 Outline 3 会显胖，2 已足够在浅色背景上保持可读
-# 修改请评估对所有 skill 录屏的影响。
 _JIANGCHANG_SUBTITLE_STYLE = (
     "FontName=Arial,FontSize=14,"
     "PrimaryColour=&H00FFFFFF,OutlineColour=&H00000000,"
@@ -18,63 +20,155 @@ _JIANGCHANG_SUBTITLE_STYLE = (
 )
 
 
+@dataclass
+class ComposeVideoResult:
+    output_path: str
+    warnings: list[str] = field(default_factory=list)
+
+
+def _escape_srt_path(path: str) -> str:
+    return path.replace("\\", "/").replace(":", "\\:")
+
+
+def _run_ffmpeg(ffmpeg_exe: Path, cmd_tail: list[str]) -> tuple[bool, str]:
+    cmd = [str(ffmpeg_exe), *cmd_tail]
+    try:
+        result = subprocess.run(
+            cmd,
+            capture_output=True,
+            text=True,
+            encoding="utf-8",
+            errors="replace",
+        )
+    except FileNotFoundError:
+        return False, "ffmpeg not found"
+    if result.returncode != 0:
+        err = (result.stderr or result.stdout or "").strip()
+        return False, err[:500] if err else f"exit {result.returncode}"
+    return True, ""
+
+
+def _media_assets_env(
+    media_assets_root: str | Path | None,
+    media_assets_env: dict[str, str] | None,
+) -> dict[str, str] | None:
+    if media_assets_root is None and media_assets_env is None:
+        return None
+    env = dict(media_assets_env or {})
+    if media_assets_root is not None:
+        env["MEDIA_ASSETS_ROOT"] = str(media_assets_root)
+    return env
+
+
 def compose_video(
     frames_dir: str,
     fps: int,
     subtitle_path: str,
-    music_dir: str,
     output_path: str,
+    *,
     music_volume: float = 0.15,
-) -> str:
-    frames_dir = Path(frames_dir)
-    subtitle_path = Path(subtitle_path)
-    output_path = Path(output_path)
-    output_path.parent.mkdir(parents=True, exist_ok=True)
+    allow_no_music: bool = True,
+    media_assets_root: str | Path | None = None,
+    media_assets_env: dict[str, str] | None = None,
+) -> ComposeVideoResult:
+    """合成 MP4；ffmpeg 与背景音乐均走 jiangchang_skill_core.media_assets。"""
+    frames_dir_path = Path(frames_dir)
+    subtitle_path_obj = Path(subtitle_path)
+    output_path_obj = Path(output_path)
+    output_path_obj.parent.mkdir(parents=True, exist_ok=True)
+    warnings: list[str] = []
 
-    # 随机选一首背景音乐
-    music_files = list(Path(music_dir).rglob("*.mp3"))
-    if not music_files:
-        raise FileNotFoundError(f"music_dir 下没有找到 MP3 文件: {music_dir}")
-    music_file = random.choice(music_files)
-    print(f"[screencast] 背景音乐: {music_file.name}")
+    assets_env = _media_assets_env(media_assets_root, media_assets_env)
 
-    # FFmpeg 字幕路径在 Windows 下需要转义冒号（subtitles 滤镜内部语法）
-    srt_path_str = str(subtitle_path).replace("\\", "/").replace(":", "\\:")
+    ffmpeg_exe = resolve_ffmpeg(env=assets_env)
+    if ffmpeg_exe is None or not Path(ffmpeg_exe).is_file():
+        raise RuntimeError("ffmpeg_not_found")
 
+    ffmpeg_path = Path(ffmpeg_exe)
+    music_file = pick_background_music(env=assets_env)
+    if music_file is None:
+        issue = background_music_issue(env=assets_env)
+        if issue:
+            warnings.append(issue)
+        else:
+            warnings.append("background_music_missing")
+        if not allow_no_music:
+            raise FileNotFoundError(warnings[-1])
+
+    srt_esc = _escape_srt_path(str(subtitle_path_obj.resolve()))
     subtitle_filter = (
-        f"subtitles='{srt_path_str}'"
+        f"subtitles='{srt_esc}'"
         f":force_style='{_JIANGCHANG_SUBTITLE_STYLE}'"
     )
 
-    # 视频和音频都放进 filter_complex，避免 -vf 与 -filter_complex 混用报错
-    filter_complex = (
-        f"[0:v]{subtitle_filter}[vout];"
-        f"[1:a]volume={music_volume},apad[aout]"
-    )
+    if music_file and music_file.is_file():
+        filter_complex = (
+            f"[0:v]{subtitle_filter}[vout];"
+            f"[1:a]volume={music_volume},apad[aout]"
+        )
+        cmd_tail = [
+            "-y",
+            "-framerate",
+            str(fps),
+            "-i",
+            str(frames_dir_path / "frame_%06d.png"),
+            "-i",
+            str(music_file),
+            "-filter_complex",
+            filter_complex,
+            "-map",
+            "[vout]",
+            "-map",
+            "[aout]",
+            "-c:v",
+            "libx264",
+            "-preset",
+            "fast",
+            "-crf",
+            "23",
+            "-c:a",
+            "aac",
+            "-b:a",
+            "128k",
+            "-shortest",
+            "-pix_fmt",
+            "yuv420p",
+            str(output_path_obj),
+        ]
+        ok, err = _run_ffmpeg(ffmpeg_path, cmd_tail)
+        if not ok:
+            warnings.append(f"ffmpeg_with_music_failed: {err}")
+            if not allow_no_music:
+                raise RuntimeError(f"ffmpeg_compose_failed: {err}")
+            music_file = None
+        else:
+            print(f"[screencast] 背景音乐: {music_file.name}")
+            print(f"[screencast] 输出: {output_path_obj}")
+            return ComposeVideoResult(str(output_path_obj.resolve()), warnings)
 
-    cmd = [
-        "ffmpeg", "-y",
-        "-framerate", str(fps),
-        "-i", str(frames_dir / "frame_%06d.png"),
-        "-i", str(music_file),
-        "-filter_complex", filter_complex,
-        "-map", "[vout]",
-        "-map", "[aout]",
-        "-c:v", "libx264",
-        "-preset", "fast",
-        "-crf", "23",
-        "-c:a", "aac",
-        "-b:a", "128k",
-        "-shortest",
-        "-pix_fmt", "yuv420p",
-        str(output_path),
+    cmd_tail = [
+        "-y",
+        "-framerate",
+        str(fps),
+        "-i",
+        str(frames_dir_path / "frame_%06d.png"),
+        "-vf",
+        subtitle_filter,
+        "-c:v",
+        "libx264",
+        "-preset",
+        "fast",
+        "-crf",
+        "23",
+        "-pix_fmt",
+        "yuv420p",
+        str(output_path_obj),
     ]
+    print("[screencast] 运行 FFmpeg 合成（无背景音乐）...")
+    ok, err = _run_ffmpeg(ffmpeg_path, cmd_tail)
+    if not ok:
+        print(err, file=sys.stderr)
+        raise RuntimeError(f"ffmpeg_compose_failed: {err}")
 
-    print(f"[screencast] 运行 FFmpeg 合成...")
-    result = subprocess.run(cmd, capture_output=True, text=True, encoding="utf-8", errors="replace")
-    if result.returncode != 0:
-        print(result.stderr, file=sys.stderr)
-        raise RuntimeError(f"FFmpeg 合成失败，退出码 {result.returncode}")
-
-    print(f"[screencast] 输出: {output_path}")
-    return str(output_path)
+    print(f"[screencast] 输出: {output_path_obj}")
+    return ComposeVideoResult(str(output_path_obj.resolve()), warnings)