Preserve phase timings across resume runs

tests/test_cli.py

@@ -377,6 +377,22 @@ class CliTests(unittest.TestCase):
                 json.dumps(existing_record, sort_keys=True) + "\n",
                 encoding="utf-8",
             )
+            (output_dir / "phase_timings.json").write_text(
+                json.dumps(
+                    {
+                        "schema_version": "phase-timings-v1",
+                        "started_at": "2026-06-17T00:00:00+00:00",
+                        "updated_at": "2026-06-17T00:00:00+00:00",
+                        "phases": {
+                            "source_acquisition_seconds": 7.0,
+                            "inference_seconds": 11.0,
+                        },
+                    },
+                    sort_keys=True,
+                )
+                + "\n",
+                encoding="utf-8",
+            )
             config_path = root / "local_batch.yaml"
             config_path.write_text(
                 "\n".join(
@@ -405,6 +421,14 @@ class CliTests(unittest.TestCase):
                 for line in manifest_path.read_text(encoding="utf-8").splitlines()
             ]
             self.assertEqual(records, [existing_record])
+            phase_timings = json.loads(
+                (output_dir / "phase_timings.json").read_text(encoding="utf-8")
+            )
+            self.assertGreaterEqual(
+                phase_timings["phases"]["source_acquisition_seconds"],
+                7.0,
+            )
+            self.assertEqual(phase_timings["phases"]["inference_seconds"], 11.0)
 
     def test_until_clips_writes_video_frame_and_clip_manifests_without_vlm(self):
         with tempfile.TemporaryDirectory() as tmp:

video_ai_analysis_poc/cli.py

@@ -33,6 +33,22 @@ def _new_phase_timings() -> dict[str, object]:
     }
 
 
+def _load_phase_timings(path: Path, *, resume: bool) -> dict[str, object]:
+    if not resume or not path.exists():
+        return _new_phase_timings()
+    try:
+        phase_timings = json.loads(path.read_text(encoding="utf-8"))
+    except (OSError, json.JSONDecodeError):
+        return _new_phase_timings()
+    if not isinstance(phase_timings, dict):
+        return _new_phase_timings()
+    if phase_timings.get("schema_version") != "phase-timings-v1":
+        return _new_phase_timings()
+    if not isinstance(phase_timings.get("phases"), dict):
+        phase_timings["phases"] = {}
+    return phase_timings
+
+
 def _write_phase_timings(
     output_dir: Path,
     phase_timings: dict[str, object],
@@ -104,10 +120,13 @@ def main(argv: Sequence[str] | None = None) -> int:
 
     output_dir = Path(config["output"]["dir"])
     output_dir.mkdir(parents=True, exist_ok=True)
-    phase_timings = _new_phase_timings()
 
     video_manifest_path = output_dir / "video_manifest.jsonl"
     resume_enabled = bool(config.get("output", {}).get("resume", False))
+    phase_timings = _load_phase_timings(
+        output_dir / "phase_timings.json",
+        resume=resume_enabled,
+    )
     records = _load_resume_records(
         video_manifest_path,
         resume=resume_enabled,