chore: sync code and project files

modules/preview_proxy.py

@@ -0,0 +1,102 @@
+"""
+Generate and cache low-bitrate preview proxies for browser playback.
+
+Goal:
+- Improve Remotion Player preview smoothness by serving smaller/faster-to-decode videos.
+- Keep original `source_path` for accurate export; only swap `source_url` for preview.
+
+Design:
+- Deterministic cache key based on (path, mtime, size).
+- Proxy lives under config.TEMP_DIR / "proxy".
+- Generated with ffmpeg: scale/pad + fps downsample + faststart + no audio.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import os
+from pathlib import Path
+from typing import Optional, Tuple
+
+import config
+from modules import ffmpeg_utils
+
+
+def _key_for_file(path: str) -> str:
+    st = os.stat(path)
+    raw = f"{path}|{st.st_mtime_ns}|{st.st_size}".encode("utf-8")
+    return hashlib.sha1(raw).hexdigest()  # short, deterministic
+
+
+def ensure_video_proxy(
+    source_path: str,
+    *,
+    target_w: int = 540,
+    target_h: int = 960,
+    target_fps: int = 24,
+    crf: int = 28,
+    preset: str = "veryfast",
+) -> Tuple[Optional[str], Optional[str]]:
+    """
+    Ensure a preview proxy exists for source_path.
+
+    Returns: (proxy_path, proxy_url) or (None, None) if source_path invalid.
+    """
+    if not source_path or not os.path.exists(source_path):
+        return None, None
+
+    proxy_dir = Path(config.TEMP_DIR) / "proxy"
+    proxy_dir.mkdir(parents=True, exist_ok=True)
+
+    key = _key_for_file(source_path)
+    out_name = f"proxy_{key}.mp4"
+    out_path = proxy_dir / out_name
+
+    if out_path.exists() and out_path.stat().st_size > 1024:
+        return str(out_path), f"/static/temp/proxy/{out_name}"
+
+    vf = (
+        f"scale={target_w}:{target_h}:force_original_aspect_ratio=decrease,"
+        f"pad={target_w}:{target_h}:(ow-iw)/2:(oh-ih)/2:black,"
+        f"fps={target_fps}"
+    )
+
+    cmd = [
+        ffmpeg_utils.FFMPEG_PATH,
+        "-y",
+        "-i",
+        source_path,
+        "-an",  # preview 不要音轨，减少解码负担（旁白/BGM 走单独轨道）
+        "-vf",
+        vf,
+        "-c:v",
+        "libx264",
+        "-preset",
+        preset,
+        "-crf",
+        str(crf),
+        "-tune",
+        "fastdecode",
+        "-pix_fmt",
+        "yuv420p",
+        "-movflags",
+        "+faststart",
+        str(out_path),
+    ]
+
+    ffmpeg_utils._run_ffmpeg(cmd)
+    if out_path.exists() and out_path.stat().st_size > 1024:
+        return str(out_path), f"/static/temp/proxy/{out_name}"
+    return None, None
+
+
+
+
+
+
+
+
+
+
+
+