feat(pipeline): master/proxy transcode arg builder (content pipeline §3.4/§6)

2026-06-24 07:54:36 -07:00
parent 7217daeb44
commit 4b5fd20374
2 changed files with 32 additions and 1 deletions
@@ -51,3 +51,21 @@ def crossfade_loop_args(src, dst, *, duration: float, overlap: float,
        "-c:v", "libx264", "-preset", "medium", "-crf", "16",
        "-pix_fmt", "yuv420p", "-movflags", "+faststart", str(dst),
    ]
+
+
+def transcode_args(src, dst, *, width: int, height: int, crf: int,
+                   fps: int = 30, ff: str = "ffmpeg") -> list[str]:
+    """Stage 4 — encode a final deliverable (master or proxy). Master: source res
+    capped ~3840 wide, crf 18. Proxy: 1920×1080, crf 20. Both H.264 High, yuv420p,
+    even dims, +faststart, video-only (spec §6)."""
+    vf = (
+        f"scale={width}:{height}:force_original_aspect_ratio=decrease,"
+        f"pad={width}:{height}:(ow-iw)/2:(oh-ih)/2,"
+        f"setsar=1,fps={fps},format=yuv420p"
+    )
+    return [
+        ff, "-y", "-i", str(src), "-vf", vf, "-an",
+        "-c:v", "libx264", "-profile:v", "high", "-preset", "slow",
+        "-crf", str(crf), "-pix_fmt", "yuv420p",
+        "-movflags", "+faststart", str(dst),
+    ]