# caption_utils.py

# Copyright (C) 2024-2026 Collabora Ltd.

#

# This library is free software; you can redistribute it and/or

# modify it under the terms of the GNU Library General Public License

# as published by the Free Software Foundation; either version 2

# of the License, or (at your option) any later version.

#

# This library is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

# Library General Public License for more details.

#

# You should have received a copy of the GNU Library General Public

# License along with this library; if not, write to the

# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

# Boston, MA 02110-1301, USA.

import os

import json

def load_captions(caption_path, logger):

"""

Load JSON caption data from a file and return a dictionary indexed by frame index.

Args:

caption_path (str): Path to the JSON caption file.

logger: Logger instance for logging messages.

Returns:

dict: Captions indexed by frame index (e.g., {0: "caption text", 1: "other text"}).

"""

if not caption_path:

logger.error("Caption file path not set.")

return {}

if not os.path.exists(caption_path):

logger.error(f"JSON file not found: {caption_path}")

return {}

try:

with open(caption_path, "r") as f:

all_data = json.load(f)

frame_data = all_data.get("frames", [])

# Store captions indexed by frame_index

captions = {

frame.get("frame_index"): frame.get("caption", "")

for frame in frame_data

}

logger.info(f"Loaded captions for {len(captions)} frames.")

return captions

except json.JSONDecodeError as e:

logger.error(f"Failed to parse JSON file: {e}")

return {}

except Exception as e:

logger.error(f"Unexpected error while loading captions: {e}")

return {}