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"""
Capture bundle reader/validator (SPECIFICATIONS.md Appendix C).

This module provides a single entry point (`CaptureBundle`) that:
- loads a bundle manifest,
- validates referenced files exist,
- offers typed accessors to common assets.
"""

from __future__ import annotations

import json
from dataclasses import dataclass
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple, Union
import numpy as np

from ..models.capture_models import CaptureManifest, DetailedAnnotation
from .dataset_layout import CaptureBundleLayout, validate_paths_exist


class CaptureBundleError(ValueError):
    pass


@dataclass(frozen=True)
class _CalibrationCompat:
    rig_extrinsics_path: Optional[str] = None
    sync_offsets_path: Optional[str] = None


@dataclass(frozen=True)
class _AnnotationsCompat:
    quick_annotation_path: Optional[str] = None
    detailed_annotation_path: Optional[str] = None


@dataclass(frozen=True)
class _DeviceCompat:
    device_id: str
    video_path: Optional[str] = None
    intrinsics_path: Optional[str] = None
    timestamps_path: Optional[str] = None
    arkit_poses_path: Optional[str] = None
    lidar_depth_dir: Optional[str] = None
    # Optional forward-compat passthrough (mirrors pydantic extra)
    model_extra: Dict[str, Any] = None  # type: ignore[assignment]


@dataclass(frozen=True)
class _ManifestCompat:
    schema_version: str
    capture_id: str
    devices: List[_DeviceCompat]
    calibration: Optional[_CalibrationCompat] = None
    annotations: Optional[_AnnotationsCompat] = None
    teacher_outputs: Optional[Any] = None
    metadata: Dict[str, Any] = None  # type: ignore[assignment]


@dataclass(frozen=True)
class CaptureBundle:
    root: Path
    # Backward-compatible view of the manifest. For v1 this is derived from
    # the pydantic model; for v2 this is synthesized from the stream registry.
    manifest: Union[CaptureManifest, _ManifestCompat]
    manifest_obj: Dict[str, Any]
    schema_version: str
    _v2_stream_index: Dict[Tuple[str, str], str]

    @classmethod
    def load(cls, root: Path) -> CaptureBundle:
        root = Path(root)
        layout = CaptureBundleLayout(root=root)
        if not root.exists():
            raise CaptureBundleError(f"Capture bundle root does not exist: {root}")
        if not layout.manifest_path.exists():
            raise CaptureBundleError(f"Missing manifest.json at: {layout.manifest_path}")

        try:
            manifest_obj = json.loads(layout.manifest_path.read_text())
        except Exception as e:
            raise CaptureBundleError(f"Failed to parse manifest.json: {e}") from e

        schema_version = str(manifest_obj.get("schema_version", "1.0") or "1.0")

        # v1: strict pydantic schema
        if schema_version.startswith("1"):
            try:
                manifest = CaptureManifest.model_validate(manifest_obj)
            except Exception as e:
                raise CaptureBundleError(f"Invalid manifest schema: {e}") from e
            bundle = cls(
                root=root,
                manifest=manifest,
                manifest_obj=manifest_obj,
                schema_version=schema_version,
                _v2_stream_index={},
            )
            bundle.validate(repairable_ok=False)
            return bundle

        # v2: stream-centric schema. Synthesize a backward-compatible manifest view.
        if not schema_version.startswith("2"):
            raise CaptureBundleError(f"Unsupported manifest schema_version: {schema_version}")

        devices = manifest_obj.get("devices", []) or []
        if not isinstance(devices, list) or not devices:
            raise CaptureBundleError("v2 manifest has no devices[] pointers")

        # Build stream index: (device_id, kind) -> stream.json path
        v2_stream_index: Dict[Tuple[str, str], str] = {}
        for s in manifest_obj.get("streams", []) or []:
            if not isinstance(s, dict):
                continue
            did = s.get("device_id")
            kind = s.get("kind")
            path = s.get("path")
            if (
                isinstance(did, str)
                and isinstance(kind, str)
                and isinstance(path, str)
                and did
                and kind
                and path
            ):
                v2_stream_index[(did, kind)] = path

        def _resolve_stream_data_rel(did: str, kind: str) -> Optional[str]:
            sp = v2_stream_index.get((did, kind))
            if not sp:
                return None
            sj_path = (root / sp).resolve()
            if not sj_path.exists():
                return None
            try:
                sj = json.loads(sj_path.read_text())
            except Exception:
                return None
            data = sj.get("data") if isinstance(sj, dict) else None
            if isinstance(data, dict) and isinstance(data.get("path"), str) and data["path"]:
                # Convert to bundle-root-relative path
                rel = (sj_path.parent / data["path"]).resolve()
                try:
                    return str(rel.relative_to(root))
                except Exception:
                    return str(rel)
            return None

        compat_devices: List[_DeviceCompat] = []
        for dref in devices:
            if not isinstance(dref, dict):
                continue
            did = dref.get("device_id")
            p = dref.get("path")
            if not (isinstance(did, str) and did and isinstance(p, str) and p):
                continue

            # Prefer stream registry for primary assets.
            video_rel = _resolve_stream_data_rel(did, "video.rgb")
            # Intrinsics: v2 prefers per-device calibration/intrinsics.json;
            # fall back to v1 intrinsics.json.
            intr_v2 = root / "devices" / did / "calibration" / "intrinsics.json"
            intr_v1 = root / "devices" / did / "intrinsics.json"
            intr_rel = None
            if intr_v2.exists():
                intr_rel = str(intr_v2.relative_to(root))
            elif intr_v1.exists():
                intr_rel = str(intr_v1.relative_to(root))

            ts_v1 = root / "devices" / did / "timestamps.json"
            ts_rel = str(ts_v1.relative_to(root)) if ts_v1.exists() else None

            poses_v1 = root / "devices" / did / "arkit_poses.json"
            poses_rel = str(poses_v1.relative_to(root)) if poses_v1.exists() else None

            depth_dir_v1 = root / "devices" / did / "depth"
            depth_dir_rel = str(depth_dir_v1.relative_to(root)) if depth_dir_v1.exists() else None

            extra_streams: Dict[str, Any] = {}
            if depth_dir_rel:
                extra_streams["depth"] = {"directory": depth_dir_rel}

            compat_devices.append(
                _DeviceCompat(
                    device_id=did,
                    video_path=video_rel,
                    intrinsics_path=intr_rel,
                    timestamps_path=ts_rel,
                    arkit_poses_path=poses_rel,
                    lidar_depth_dir=None,
                    model_extra={"streams": extra_streams} if extra_streams else {},
                )
            )

        if not compat_devices:
            raise CaptureBundleError("v2 manifest has no usable device entries")

        # Calibration + annotations compat: map well-known files when present.
        calib_files = []
        calib = (
            manifest_obj.get("calibration")
            if isinstance(manifest_obj.get("calibration"), dict)
            else {}
        )
        if isinstance(calib, dict) and isinstance(calib.get("files"), list):
            calib_files = [str(x) for x in calib.get("files") if isinstance(x, str)]
        cal = _CalibrationCompat(
            rig_extrinsics_path=(
                "calibration/rig_extrinsics.json"
                if "calibration/rig_extrinsics.json" in calib_files
                else None
            ),
            sync_offsets_path=(
                "calibration/sync_offsets.json"
                if "calibration/sync_offsets.json" in calib_files
                else None
            ),
        )

        ann_files = []
        anns = (
            manifest_obj.get("annotations")
            if isinstance(manifest_obj.get("annotations"), dict)
            else {}
        )
        if isinstance(anns, dict) and isinstance(anns.get("files"), list):
            ann_files = [str(x) for x in anns.get("files") if isinstance(x, str)]
        ann = _AnnotationsCompat(
            quick_annotation_path=(
                "annotations/quick_annotation.json"
                if "annotations/quick_annotation.json" in ann_files
                else None
            ),
            detailed_annotation_path=(
                "annotations/detailed_annotation.json"
                if "annotations/detailed_annotation.json" in ann_files
                else None
            ),
        )

        compat_manifest = _ManifestCompat(
            schema_version=schema_version,
            capture_id=str(manifest_obj.get("capture_id") or ""),
            devices=compat_devices,
            calibration=cal,
            annotations=ann,
            metadata={},
        )

        bundle = cls(
            root=root,
            manifest=compat_manifest,
            manifest_obj=manifest_obj,
            schema_version=schema_version,
            _v2_stream_index=v2_stream_index,
        )
        bundle.validate(repairable_ok=False)
        return bundle

    @property
    def layout(self) -> CaptureBundleLayout:
        return CaptureBundleLayout(root=self.root)

    def validate(self, repairable_ok: bool = True) -> None:
        """
        Validate that referenced paths exist.

        If `repairable_ok` is True, missing optional assets do not fail validation.
        """
        rels: List[Optional[str]] = []
        devices = getattr(self.manifest, "devices", []) or []
        for d in devices:
            rels.extend(
                [
                    getattr(d, "video_path", None),
                    getattr(d, "intrinsics_path", None),
                    getattr(d, "timestamps_path", None),
                    getattr(d, "arkit_poses_path", None),
                ]
            )
            rels.append(getattr(d, "lidar_depth_dir", None))
            # WaveformMobile forward-compat: some manifests store depth under
            # device.extra.streams.depth.
            # Prefer lidar_depth_dir, but validate stream directory when present.
            extra = getattr(d, "model_extra", None) or {}
            streams = extra.get("streams") if isinstance(extra, dict) else None
            if isinstance(streams, dict):
                depth = streams.get("depth")
                if isinstance(depth, dict):
                    rel = depth.get("directory")
                    if isinstance(rel, str) and rel:
                        rels.append(rel)

        if getattr(self.manifest, "calibration", None):
            cal = self.manifest.calibration  # type: ignore[union-attr]
            rels.extend(
                [
                    getattr(cal, "rig_extrinsics_path", None),
                    getattr(cal, "sync_offsets_path", None),
                ]
            )
        if getattr(self.manifest, "annotations", None):
            ann = self.manifest.annotations  # type: ignore[union-attr]
            rels.extend(
                [
                    getattr(ann, "quick_annotation_path", None),
                    getattr(ann, "detailed_annotation_path", None),
                ]
            )
        if getattr(self.manifest, "teacher_outputs", None):
            tout = self.manifest.teacher_outputs  # type: ignore[union-attr]
            rels.extend(
                [
                    getattr(tout, "depth_dir", None),
                    getattr(tout, "uncertainty_dir", None),
                    getattr(tout, "reconstruction_path", None),
                ]
            )

        errors = validate_paths_exist(self.root, rels)
        if errors and not repairable_ok:
            raise CaptureBundleError("Capture bundle validation failed:\n- " + "\n- ".join(errors))

    # ---- Convenience accessors -------------------------------------------------

    def list_devices(self) -> List[str]:
        devices = getattr(self.manifest, "devices", []) or []
        return [str(getattr(d, "device_id")) for d in devices]

    def get_device(self, device_id: str):
        devices = getattr(self.manifest, "devices", []) or []
        for d in devices:
            if str(getattr(d, "device_id")) == device_id:
                return d
        raise CaptureBundleError(f"Unknown device_id: {device_id}")

    def device_video_path(self, device_id: str) -> Path:
        d = self.get_device(device_id)
        if not getattr(d, "video_path", None):
            raise CaptureBundleError(
                f"No video_path for device_id={device_id} (schema_version={self.schema_version})"
            )
        return (self.root / str(getattr(d, "video_path"))).resolve()

    def device_intrinsics_path(self, device_id: str) -> Path:
        d = self.get_device(device_id)
        if not getattr(d, "intrinsics_path", None):
            raise CaptureBundleError(
                f"No intrinsics_path for device_id={device_id} "
                f"(schema_version={self.schema_version})"
            )
        return (self.root / str(getattr(d, "intrinsics_path"))).resolve()

    def device_timestamps_path(self, device_id: str) -> Path:
        d = self.get_device(device_id)
        if not getattr(d, "timestamps_path", None):
            raise CaptureBundleError(
                f"No timestamps_path for device_id={device_id} "
                f"(schema_version={self.schema_version}). "
                "Use the timeline.frames stream (v2) instead."
            )
        return (self.root / str(getattr(d, "timestamps_path"))).resolve()

    def device_arkit_poses_path(self, device_id: str) -> Optional[Path]:
        d = self.get_device(device_id)
        if not getattr(d, "arkit_poses_path", None):
            return None
        return (self.root / str(getattr(d, "arkit_poses_path"))).resolve()

    def device_lidar_depth_dir(self, device_id: str) -> Optional[Path]:
        d = self.get_device(device_id)
        if not getattr(d, "lidar_depth_dir", None):
            return None
        return (self.root / str(getattr(d, "lidar_depth_dir"))).resolve()

    def device_depth_dir_best_effort(self, device_id: str) -> Optional[Path]:
        """
        Prefer canonical `lidar_depth_dir`, but fall back to WaveformMobile packed stream directory
        stored under `device.streams.depth.directory` if present.
        """
        d = self.get_device(device_id)
        if getattr(d, "lidar_depth_dir", None):
            p = (self.root / str(getattr(d, "lidar_depth_dir"))).resolve()
            return p
        extra = getattr(d, "model_extra", None) or {}
        if not isinstance(extra, dict):
            return None
        streams = extra.get("streams")
        if not isinstance(streams, dict):
            return None
        depth = streams.get("depth")
        if not isinstance(depth, dict):
            return None
        rel = depth.get("directory")
        if not isinstance(rel, str) or not rel:
            return None
        return (self.root / rel).resolve()

    # ---- v2 stream-centric helpers --------------------------------------------

    def v2_has_streams(self) -> bool:
        return bool(self.schema_version.startswith("2") and self._v2_stream_index)

    def v2_stream_ref(self, *, device_id: str, kind: str) -> Optional[Path]:
        """
        Return the path to `stream.json` for (device_id, kind) when present in v2.
        """
        if not self.schema_version.startswith("2"):
            return None
        rel = self._v2_stream_index.get((device_id, kind))
        return (self.root / rel).resolve() if rel else None

    def v2_stream_json(self, *, device_id: str, kind: str) -> Optional[Dict[str, Any]]:
        p = self.v2_stream_ref(device_id=device_id, kind=kind)
        if not p or not p.exists():
            return None
        try:
            obj = json.loads(p.read_text())
            return obj if isinstance(obj, dict) else None
        except Exception:
            return None

    def v2_stream_data_path(self, *, device_id: str, kind: str) -> Optional[Path]:
        sj = self.v2_stream_json(device_id=device_id, kind=kind)
        if not sj:
            return None
        sp = self.v2_stream_ref(device_id=device_id, kind=kind)
        if not sp:
            return None
        data = sj.get("data") if isinstance(sj.get("data"), dict) else None
        if not isinstance(data, dict):
            return None
        rel = data.get("path")
        if not isinstance(rel, str) or not rel:
            return None
        return (sp.parent / rel).resolve()

    # ---- WaveformMobile optional sensor streams -----------------------------------------

    def _device_streams_extra(self, device_id: str) -> Dict[str, Any]:
        d = self.get_device(device_id)
        extra = getattr(d, "model_extra", None) or {}
        if not isinstance(extra, dict):
            return {}
        streams = extra.get("streams")
        return streams if isinstance(streams, dict) else {}

    def device_imu_paths(
        self, device_id: str
    ) -> tuple[Optional[Path], Optional[Path], Optional[Path]]:
        """
        Return (imu_stream.bin, imu_frames.bin, imu_index.json) paths when present
        in device.streams.imu.
        """
        streams = self._device_streams_extra(device_id)
        imu = streams.get("imu")
        if not isinstance(imu, dict):
            return (None, None, None)
        stream = imu.get("stream")
        frames = imu.get("frames")
        index = imu.get("index")
        sp = (self.root / str(stream)).resolve() if isinstance(stream, str) and stream else None
        fp = (self.root / str(frames)).resolve() if isinstance(frames, str) and frames else None
        ip = (self.root / str(index)).resolve() if isinstance(index, str) and index else None
        return (sp, fp, ip)

    def device_barometer_paths(self, device_id: str) -> tuple[Optional[Path], Optional[Path]]:
        """
        Return (barometer_stream.bin, barometer/index.json) paths when present in
        device.streams.barometer.
        """
        streams = self._device_streams_extra(device_id)
        bar = streams.get("barometer")
        if not isinstance(bar, dict):
            return (None, None)
        stream = bar.get("stream")
        index = bar.get("index")
        sp = (self.root / str(stream)).resolve() if isinstance(stream, str) and stream else None
        ip = (self.root / str(index)).resolve() if isinstance(index, str) and index else None
        return (sp, ip)

    def load_detailed_annotation(self) -> Optional[DetailedAnnotation]:
        if not self.manifest.annotations or not self.manifest.annotations.detailed_annotation_path:
            return None
        p = (self.root / self.manifest.annotations.detailed_annotation_path).resolve()
        if not p.exists():
            return None
        try:
            obj = json.loads(p.read_text())
            return DetailedAnnotation.model_validate(obj)
        except Exception as e:
            raise CaptureBundleError(f"Failed to parse detailed annotation: {p}: {e}") from e

    def load_intrinsics_matrix(self, device_id: str) -> np.ndarray:
        """
        Load intrinsics from JSON as a (3, 3) float32 matrix.

        The exact intrinsics JSON schema is intentionally flexible; we accept:
        - {"K": [[...],[...],[...]]} or
        - {"intrinsics": [[...],[...],[...]]} or
        - {"fx":..., "fy":..., "cx":..., "cy":...}
        """
        p = self.device_intrinsics_path(device_id)
        obj = json.loads(p.read_text())
        if "K" in obj:
            K = np.asarray(obj["K"], dtype=np.float32)
        elif "intrinsics" in obj:
            K = np.asarray(obj["intrinsics"], dtype=np.float32)
        elif all(k in obj for k in ("fx", "fy", "cx", "cy")):
            fx, fy, cx, cy = float(obj["fx"]), float(obj["fy"]), float(obj["cx"]), float(obj["cy"])
            K = np.array([[fx, 0.0, cx], [0.0, fy, cy], [0.0, 0.0, 1.0]], dtype=np.float32)
        else:
            raise CaptureBundleError(f"Unsupported intrinsics JSON schema: {p}")
        if K.shape != (3, 3):
            raise CaptureBundleError(f"Intrinsics must be 3x3, got {K.shape} in {p}")
        return K

    def load_intrinsics_and_distortion(
        self, device_id: str
    ) -> tuple[np.ndarray, Optional[np.ndarray]]:
        """
        Load intrinsics matrix K and (optional) distortion coefficients.

        Distortion support is best-effort and forward-compatible. Accepted keys:
        - {"distortion": [...]} (OpenCV-style coeffs)
        - {"dist": [...]} or {"dist_coeffs": [...]}
        - {"k": [...]} (legacy)
        """
        p = self.device_intrinsics_path(device_id)
        obj = json.loads(p.read_text())
        K = self.load_intrinsics_matrix(device_id)
        dist = None
        for key in ("distortion", "dist", "dist_coeffs", "k"):
            if key in obj and isinstance(obj[key], list):
                try:
                    dist = np.asarray(obj[key], dtype=np.float64).reshape(-1)
                except Exception:
                    dist = None
                break
        return K.astype(np.float32, copy=False), dist

    def load_sync_offsets(self) -> Optional[Dict[str, float]]:
        """
        Load per-device sync offsets (seconds) if available.
        """
        if not self.manifest.calibration or not self.manifest.calibration.sync_offsets_path:
            return None
        p = (self.root / self.manifest.calibration.sync_offsets_path).resolve()
        if not p.exists():
            return None
        obj = json.loads(p.read_text())
        # Expected {device_id: offset_seconds}
        return {str(k): float(v) for k, v in obj.items()}

    def load_rig_extrinsics(self) -> Optional[Dict[str, Any]]:
        """
        Load rig extrinsics if available.

        The exact schema is not locked yet; we return raw JSON for now.
        """
        if not self.manifest.calibration or not self.manifest.calibration.rig_extrinsics_path:
            return None
        p = (self.root / self.manifest.calibration.rig_extrinsics_path).resolve()
        if not p.exists():
            return None
        return json.loads(p.read_text())