Safer video loading from SLP

sleap_io/io/main.py

@@ -7,16 +7,19 @@
 from pathlib import Path
 
 
-def load_slp(filename: str) -> Labels:
+def load_slp(filename: str, open_videos: bool = True) -> Labels:
  """Load a SLEAP dataset.
 
  Args:
  filename: Path to a SLEAP labels file (`.slp`).
+ open_videos: If `True` (the default), attempt to open the video backend for
+ I/O. If `False`, the backend will not be opened (useful for reading metadata
+ when the video files are not available).
 
  Returns:
  The dataset as a `Labels` object.
  """
- return slp.read_labels(filename)
+ return slp.read_labels(filename, open_videos=open_videos)
 
 
 def save_slp(

sleap_io/io/slp.py

@@ -44,7 +44,10 @@ class InstanceType(IntEnum):
 
 
 def make_video(
- labels_path: str, video_json: dict, video_ind: int | None = None
+ labels_path: str,
+ video_json: dict,
+ video_ind: int | None = None,
+ open_backend: bool = True,
 ) -> Video:
  """Create a `Video` object from a JSON dictionary.
 
@@ -53,6 +56,9 @@ def make_video(
  video_json: A dictionary containing the video metadata.
  video_ind: The index of the video in the labels file. This is used to try to
  recover the source video for embedded videos. This is skipped if `None`.
+ open_backend: If `True` (the default), attempt to open the video backend for
+ I/O. If `False`, the backend will not be opened (useful for reading metadata
+ when the video files are not available).
  """
  backend_metadata = video_json["backend"]
  video_path = backend_metadata["filename"]
@@ -67,22 +73,6 @@ def make_video(
  # Basic path resolution.
  video_path = Path(Path(video_path).as_posix().replace("\\", "/"))
 
- try:
- if not video_path.exists():
- # Check for the same filename in the same directory as the labels file.
- video_path_ = Path(labels_path).parent / video_path.name
- if video_path_.exists():
- video_path = video_path_
- else:
- # TODO (TP): Expand capabilities of path resolution to support more
- # complex path finding strategies.
- pass
- except OSError:
- pass
-
- # Convert video path to string.
- video_path = video_path.as_posix()
-
  if is_embedded:
  # Try to recover the source video.
  with h5py.File(labels_path, "r") as f:
@@ -91,23 +81,44 @@ def make_video(
  f[f"video{video_ind}/source_video"].attrs["json"]
  )
  source_video = make_video(
- labels_path, source_video_json, video_ind=None
+ labels_path,
+ source_video_json,
+ video_ind=None,
+ open_backend=open_backend,
  )
 
- if "filenames" in backend_metadata:
- # This is an ImageVideo.
- # TODO: Path resolution.
- video_path = backend_metadata["filenames"]
-
- try:
- backend = VideoBackend.from_filename(
- video_path,
- dataset=backend_metadata.get("dataset", None),
- grayscale=backend_metadata.get("grayscale", None),
- input_format=backend_metadata.get("input_format", None),
- )
- except ValueError:
- backend = None
+ backend = None
+ if open_backend:
+ try:
+ if not video_path.exists():
+ # Check for the same filename in the same directory as the labels file.
+ video_path_ = Path(labels_path).parent / video_path.name
+ if video_path_.exists() and video_path.stat():
+ video_path = video_path_
+ else:
+ # TODO (TP): Expand capabilities of path resolution to support more
+ # complex path finding strategies.
+ pass
+ except (OSError, PermissionError, FileNotFoundError):
+ pass
+
+ # Convert video path to string.
+ video_path = video_path.as_posix()
+
+ if "filenames" in backend_metadata:
+ # This is an ImageVideo.
+ # TODO: Path resolution.
+ video_path = backend_metadata["filenames"]
+
+ try:
+ backend = VideoBackend.from_filename(
+ video_path,
+ dataset=backend_metadata.get("dataset", None),
+ grayscale=backend_metadata.get("grayscale", None),
+ input_format=backend_metadata.get("input_format", None),
+ )
+ except:
+ backend = None
 
  return Video(
  filename=video_path,
@@ -117,11 +128,14 @@ def make_video(
  )
 
 
-def read_videos(labels_path: str) -> list[Video]:
+def read_videos(labels_path: str, open_backend: bool = False) -> list[Video]:
  """Read `Video` dataset in a SLEAP labels file.
 
  Args:
  labels_path: A string path to the SLEAP labels file.
+ open_backend: If `True` (the default), attempt to open the video backend for
+ I/O. If `False`, the backend will not be opened (useful for reading metadata
+ when the video files are not available).
 
  Returns:
  A list of `Video` objects.
@@ -131,7 +145,9 @@ def read_videos(labels_path: str) -> list[Video]:
  read_hdf5_dataset(labels_path, "videos_json")
  ):
  video_json = json.loads(video_data)
- video = make_video(labels_path, video_json, video_ind=video_ind)
+ video = make_video(
+ labels_path, video_json, video_ind=video_ind, open_backend=open_backend
+ )
  videos.append(video)
  return videos
 
@@ -1003,17 +1019,20 @@ def write_lfs(labels_path: str, labels: Labels):
  )
 
 
-def read_labels(labels_path: str) -> Labels:
+def read_labels(labels_path: str, open_videos: bool = True) -> Labels:
  """Read a SLEAP labels file.
 
  Args:
  labels_path: A string path to the SLEAP labels file.
+ open_videos: If `True` (the default), attempt to open the video backend for
+ I/O. If `False`, the backend will not be opened (useful for reading metadata
+ when the video files are not available).
 
  Returns:
  The processed `Labels` object.
  """
  tracks = read_tracks(labels_path)
- videos = read_videos(labels_path)
+ videos = read_videos(labels_path, open_backend=open_videos)
  skeletons = read_skeletons(labels_path)
  points = read_points(labels_path)
  pred_points = read_pred_points(labels_path)