exifmwg 0.4.0

A Python interface to read and write Metadata Working Group fields using exiftool

EXIF Metadata Working Group Tool

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Table of Contents

• What
• Features
• Requirements
• Installation
• Usage
  • Quick Start
  • Reading and Modifying Image Regions
  • Working with Keyword Hierarchies
• Documentation
• License

What

This library is a wrapper around Exiv2 to simplify the reading and writing of image metadata fields as defined by the Metadata Working Group. The specification Guidelines for Handling Image Metadata (PDF) defines a structured way to resolve certain common fields across the various versions and standards for image metadata.

Features

• Simplified Metadata Management: Directly links to Exiv2 to read or set the common MWG fields
• Strongly Typed Interface: All functions, properties and returns are typed
• Key Metadata Fields:
  • XMP-mwg-kw:KeywordInfo
    • Read & write hierarchical keyword/tag trees. Reading syncs from the MWG structures, but also other fields like Xmp.digiKam.TagsList. When writing, these fields are also set. This allows for maximum compatibility
  • XMP-mwg-rs:RegionInfo - Manage region annotations for images (face tagging, object recognition boxes)
  • MWG:Description - Access standardized image descriptions across metadata formats
  • Title - Manage image titles consistently. Though not defined by MWG, it is often displayed by image programs
  • Location - Define the image location, using the Country, State, City and Sub-Location
• Extensive testing: Tested via both Python and C++ unit tests, with code coverage, including branch coverage information

Requirements

• Python 3.9 or higher

Installation

pip install exifmwg

Usage

Quick Start

from pathlib import Path
from exifmwg import ImageMetadata

# Read metadata from an image
metadata = ImageMetadata(Path("sample.jpg"))
# Print the image title
print(f"Image title: {metadata.Title}")

# Set a new title and description
metadata.Title = "Sunset at the Beach"
metadata.Description = "Beautiful sunset captured at Malibu Beach"

# Save the updates to the original file
metadata.to_file()

# Save the updates to a new file
metadata.to_file(Path("updated_sample.jpg"))

Reading and Modifying Image Regions

from pathlib import Path
from exifmwg import ImageMetadata

test_file = Path("sample.jpeg")

# Read metadata from image
metadata = ImageMetadata(test_file)

# Print the defined regions and their type for an image
for region in metadata.RegionInfo.RegionList:
    print(f"Name: {region.Name}, Type: {region.Type}, Description: {region.Description or '(None)'}")

# Change the person's name in the first region
metadata.RegionInfo.RegionList[0].Name = "Billy Bob"
# Save the updates to the original file
metadata.to_file()

Example output:

Name: John Smith, Type: Face, Description: Family member
Name: Rover, Type: Pet, Description: Family dog

Working with Keyword Hierarchies

from pathlib import Path
from exifmwg import ImageMetadata
from exifmwg import Keyword
from exifmwg import KeywordInfo

test_file = Path("sample.jpeg")

metadata = ImageMetadata(test_file)

# Create a new keyword hierarchy
new_keyword_tree = Keyword(
    Keyword="Vacation",
    Children=[
        models.Keyword(Keyword="Beach"),
        models.Keyword(Keyword="Mountain")
    ]
)

# Overwrite any existing keywords
metadata.keyword_info = KeywordInfo(hierarchy=[new_keyword_tree])

# Save the updates to the original file
metadata.to_file()

Documentation

For more detailed information about using this library, refer to:

• API Documentation (This is still a TODO item)
• ExifTool MWG Tags

License

exifmwg is distributed under the terms of the Mozilla Public License 2.0 license.