feat(pipeline): runner + opt-in integration test on real forest base (content pipeline §3)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tools/pipeline/run.py

@@ -0,0 +1,49 @@
+"""Thin runner: ffprobe the source, then execute the frame -> loop -> transcode
+stages with tools.pipeline.ffmpeg_ops. The pure arg builders are unit-tested;
+this glue is covered by the opt-in integration test."""
+
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+
+from .ffmpeg_ops import crossfade_loop_args, frame_args, transcode_args
+
+MASTER_MAX_W = 3840
+
+
+def probe_duration(src, *, ff: str = "ffprobe") -> float:
+    out = subprocess.run(
+        [ff, "-v", "quiet", "-show_entries", "format=duration",
+         "-of", "csv=p=0", str(src)],
+        capture_output=True, text=True, check=True,
+    ).stdout.strip()
+    return float(out)
+
+
+def _run(args: list[str]) -> None:
+    subprocess.run(args, check=True, capture_output=True)
+
+
+def process_clip(src, out_dir, *, start: float = 0.0, duration: float | None = None,
+                 overlap: float = 1.0, master_w: int = 3840, master_h: int = 2160,
+                 ff: str = "ffmpeg") -> dict:
+    """Run stages 2–4 for one clip; return {'master','proxy','loop','mezzanine'} paths.
+    `duration` defaults to the full source length (minus the trim start)."""
+    src = Path(src)
+    out_dir = Path(out_dir)
+    out_dir.mkdir(parents=True, exist_ok=True)
+    if duration is None:
+        duration = probe_duration(src) - start
+
+    mezz = out_dir / "mezzanine.mp4"
+    loop = out_dir / "loop.mp4"
+    master = out_dir / "master.mp4"
+    proxy = out_dir / "base.mp4"          # the proxy is what the manifest's base_file points at
+
+    _run(frame_args(src, mezz, start=start, duration=duration,
+                    width=master_w, height=master_h, ff=ff))
+    _run(crossfade_loop_args(mezz, loop, duration=duration, overlap=overlap, ff=ff))
+    _run(transcode_args(loop, master, width=master_w, height=master_h, crf=18, ff=ff))
+    _run(transcode_args(loop, proxy, width=1920, height=1080, crf=20, ff=ff))
+    return {"mezzanine": mezz, "loop": loop, "master": master, "proxy": proxy}