auto-commit for 14921357-f5e2-4aba-b4c1-a07a52c800cc

backend/transcode.py

@@ -0,0 +1,74 @@
+"""HLS transcoding via ffmpeg. Background-runs and updates DB."""
+import asyncio
+import logging
+import shutil
+from pathlib import Path
+from typing import Optional
+
+logger = logging.getLogger("kino.transcode")
+
+
+async def transcode_to_hls(
+    source: Path,
+    out_dir: Path,
+    on_status,
+):
+    """
+    Run ffmpeg to produce HLS playlist + segments.
+    `on_status(status, error=None)` is awaited at start/end with status one of
+    'running'|'done'|'failed'.
+    Uses stream-copy where possible (fast, no re-encode).
+    """
+    if not source.is_file():
+        await on_status("failed", error=f"Source missing: {source}")
+        return
+    out_dir.mkdir(parents=True, exist_ok=True)
+    playlist = out_dir / "playlist.m3u8"
+
+    cmd = [
+        "ffmpeg", "-y",
+        "-i", str(source),
+        "-c:v", "copy",
+        "-c:a", "copy",
+        "-bsf:v", "h264_mp4toannexb",
+        "-f", "hls",
+        "-hls_time", "6",
+        "-hls_list_size", "0",
+        "-hls_playlist_type", "vod",
+        "-hls_segment_filename", str(out_dir / "seg_%04d.ts"),
+        str(playlist),
+    ]
+
+    await on_status("running")
+    try:
+        proc = await asyncio.create_subprocess_exec(
+            *cmd, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE,
+        )
+        _stdout, stderr = await proc.communicate()
+        if proc.returncode != 0:
+            err = stderr.decode("utf-8", errors="ignore")[-500:]
+            logger.error(f"ffmpeg failed: {err}")
+            await on_status("failed", error=err[:200])
+            # cleanup partial files
+            shutil.rmtree(out_dir, ignore_errors=True)
+            return
+        await on_status("done")
+    except FileNotFoundError:
+        await on_status("failed", error="ffmpeg not installed")
+    except Exception as e:
+        logger.exception("transcode crashed")
+        await on_status("failed", error=str(e))
+        shutil.rmtree(out_dir, ignore_errors=True)
+
+
+def srt_to_vtt(srt_text: str) -> str:
+    """Convert SRT subtitles to WebVTT format (simple, no styling)."""
+    lines = srt_text.replace("\r\n", "\n").split("\n")
+    out = ["WEBVTT", ""]
+    for line in lines:
+        # Replace SRT timestamp commas with VTT dots
+        if "-->" in line:
+            out.append(line.replace(",", "."))
+        else:
+            out.append(line)
+    return "\n".join(out)