Update app/video_preprocess.py

app/video_preprocess.py

@@ -1,159 +1,142 @@
-from __future__ import annotations
-
-import os
-import shutil
-import subprocess
-from dataclasses import dataclass
-from datetime import datetime
-
-
-@dataclass
-class PreprocessResult:
-    input_path: str
-    output_path: str
-    used_ffmpeg: bool
-    message: str
-    mode: str
-    ffmpeg_cmd: list[str]
-
-
-def check_ffmpeg_available() -> bool:
-    return shutil.which("ffmpeg") is not None
-
-
-def ensure_dir(path: str) -> None:
-    os.makedirs(path, exist_ok=True)
-
-
-def build_preprocessed_video_path(output_dir: str, input_path: str, mode: str) -> str:
-    ensure_dir(output_dir)
-    stem = os.path.splitext(os.path.basename(input_path))[0]
-    ts = datetime.now().strftime("%Y%m%d_%H%M%S")
-    return os.path.join(output_dir, f"{stem}_{mode}_preprocessed_{ts}.mp4")
-
-
-def _build_ffmpeg_cmd(
-    input_path: str,
-    output_path: str,
-    *,
-    mode: str = "analysis",
-    remove_audio: bool = False,
-) -> list[str]:
-    """
-    三种模式：
-    - preview:      调试/预览，体积更小
-    - analysis:     正式分析，推荐，尽量保真
-    - archival:     更高保真，体积更大
-
-    说明：
-    - 音频默认保留
-    - 使用 H.264 + AAC，兼容性最好
-    - 使用 CRF 控质量；CRF 越小越保真
-    """
-    mode = (mode or "analysis").lower().strip()
-    if mode not in {"preview", "analysis", "archival"}:
-        raise ValueError(f"不支持的预处理模式: {mode}")
-
-    if mode == "preview":
-        # 调试演示用，较小
-        width = 640
-        fps = 12
-        crf = 26
-        preset = "veryfast"
-        audio_bitrate = "96k"
-    elif mode == "analysis":
-        # 推荐：正式分析档
-        width = 1280
-        fps = 15
-        crf = 18
-        preset = "slow"
-        audio_bitrate = "128k"
-    else:  # archival
-        # 更高保真
-        width = 1280
-        fps = 20
-        crf = 16
-        preset = "slow"
-        audio_bitrate = "160k"
-
-    # 保持纵横比，高度自动偶数对齐
-    vf = f"scale='min({width},iw)':-2,fps={fps}"
-
-    cmd = [
-        "ffmpeg",
-        "-y",
-        "-i", input_path,
-        "-vf", vf,
-        "-c:v", "libx264",
-        "-preset", preset,
-        "-crf", str(crf),
-        "-movflags", "+faststart",
-        "-pix_fmt", "yuv420p",
-    ]
-
-    if remove_audio:
-        cmd += ["-an"]
-    else:
-        # 明确保留音频
-        cmd += [
-            "-c:a", "aac",
-            "-b:a", audio_bitrate,
-            "-ac", "1",
-            "-ar", "16000",
-        ]
-
-    cmd.append(output_path)
-    return cmd
-
-
-def preprocess_video(
-    input_path: str,
-    output_dir: str,
-    mode: str = "analysis",
-    remove_audio: bool = False,
-) -> PreprocessResult:
-    """
-    使用 ffmpeg 对视频做轻量预处理。
-
-    推荐：
-    - 正式分析：mode="analysis"
-    - 预览调试：mode="preview"
-    - 高保真留档：mode="archival"
-
-    注意：
-    - 这里默认保留音频
-    - 若 remove_audio=True，会显式去掉音频
-    """
-    if not os.path.exists(input_path):
-        raise FileNotFoundError(f"视频文件不存在: {input_path}")
-
-    if not check_ffmpeg_available():
-        raise RuntimeError("未检测到 ffmpeg，请先安装 ffmpeg。")
-
-    output_path = build_preprocessed_video_path(output_dir, input_path, mode)
-    cmd = _build_ffmpeg_cmd(
-        input_path=input_path,
-        output_path=output_path,
-        mode=mode,
-        remove_audio=remove_audio,
-    )
-
-    proc = subprocess.run(
-        cmd,
-        stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE,
-        text=True,
-    )
-
-    if proc.returncode != 0:
-        raise RuntimeError(f"ffmpeg 预处理失败:\n{proc.stderr}")
-
-    return PreprocessResult(
-        input_path=input_path,
-        output_path=output_path,
-        used_ffmpeg=True,
-        message=f"视频预处理完成（mode={mode}, audio={'removed' if remove_audio else 'kept'}）",
-        mode=mode,
-        ffmpeg_cmd=cmd,
-    )
-
+from __future__ import annotations
+
+import os
+import shutil
+import subprocess
+from dataclasses import dataclass
+from datetime import datetime
+
+
+@dataclass
+class PreprocessResult:
+    input_path: str
+    output_path: str
+    used_ffmpeg: bool
+    message: str
+    mode: str
+    ffmpeg_cmd: list[str]
+
+
+def check_ffmpeg_available() -> bool:
+    return shutil.which("ffmpeg") is not None
+
+
+def ensure_dir(path: str) -> None:
+    os.makedirs(path, exist_ok=True)
+
+
+def build_preprocessed_video_path(output_dir: str, input_path: str, mode: str) -> str:
+    ensure_dir(output_dir)
+    stem = os.path.splitext(os.path.basename(input_path))[0]
+    ts = datetime.now().strftime("%Y%m%d_%H%M%S")
+    return os.path.join(output_dir, f"{stem}_{mode}_preprocessed_{ts}.mp4")
+
+
+def _build_ffmpeg_cmd(
+    input_path: str,
+    output_path: str,
+    *,
+    mode: str = "analysis",
+    remove_audio: bool = False,
+) -> list[str]:
+    """
+    我在这里设置了三种可选择的模式：
+    - preview:      调试/预览，体积更小
+    - analysis:     正式分析，推荐，尽量保真
+    - archival:     更高保真，体积更大
+
+    说明一下：
+    - 音频默认保留
+    - 使用 H.264 + AAC，兼容性最好
+    - 使用 CRF 控质量；CRF 越小越保真
+    """
+    mode = (mode or "analysis").lower().strip()
+    if mode not in {"preview", "analysis", "archival"}:
+        raise ValueError(f"不支持的预处理模式: {mode}")
+
+    if mode == "preview":
+        width = 640
+        fps = 12
+        crf = 26
+        preset = "veryfast"
+        audio_bitrate = "96k"
+    elif mode == "analysis":
+        width = 1280
+        fps = 15
+        crf = 18
+        preset = "slow"
+        audio_bitrate = "128k"
+    else:  # archival
+        width = 1280
+        fps = 20
+        crf = 16
+        preset = "slow"
+        audio_bitrate = "160k"
+
+    vf = f"scale='min({width},iw)':-2,fps={fps}"
+
+    cmd = [
+        "ffmpeg",
+        "-y",
+        "-i", input_path,
+        "-vf", vf,
+        "-c:v", "libx264",
+        "-preset", preset,
+        "-crf", str(crf),
+        "-movflags", "+faststart",
+        "-pix_fmt", "yuv420p",
+    ]
+
+    if remove_audio:
+        cmd += ["-an"]
+    else:
+        cmd += [
+            "-c:a", "aac",
+            "-b:a", audio_bitrate,
+            "-ac", "1",
+            "-ar", "16000",
+        ]
+
+    cmd.append(output_path)
+    return cmd
+
+
+def preprocess_video(
+    input_path: str,
+    output_dir: str,
+    mode: str = "analysis",
+    remove_audio: bool = False,
+) -> PreprocessResult:
+    if not os.path.exists(input_path):
+        raise FileNotFoundError(f"视频文件不存在: {input_path}")
+
+    if not check_ffmpeg_available():
+        raise RuntimeError("未检测到 ffmpeg，请先安装 ffmpeg。")
+
+    output_path = build_preprocessed_video_path(output_dir, input_path, mode)
+    cmd = _build_ffmpeg_cmd(
+        input_path=input_path,
+        output_path=output_path,
+        mode=mode,
+        remove_audio=remove_audio,
+    )
+
+    proc = subprocess.run(
+        cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        text=True,
+    )
+
+    if proc.returncode != 0:
+        raise RuntimeError(f"ffmpeg 预处理失败:\n{proc.stderr}")
+
+    return PreprocessResult(
+        input_path=input_path,
+        output_path=output_path,
+        used_ffmpeg=True,
+        message=f"视频预处理完成（mode={mode}, audio={'removed' if remove_audio else 'kept'}）",
+        mode=mode,
+        ffmpeg_cmd=cmd,
+    )
+