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photoextractor photoextractor

The photoextractor R package allows you to extract pictograms (frames) from videos while preserving and stamping the original metadata from the video into the extracted images.

Installation

You can install photoextractor from CRAN with:

# install.packages("photoextractor")

You can install the development version of photoextractor from GitHub with:

devtools::install_github("dlizcano/photoextractor")

External Dependencies

This package relies on ExifTool. After installing the package, you must ensure ExifTool is available. The exiftoolr package can download it for you:

exiftoolr::install_exiftool()

Usage

🎬 Single Video Extraction

To extract frames from a single video (avi|mp4|mov|mkv|m4v):

library(photoextractor)

# Create an extractor object
ext <- VideoFrameExtractor(
  video_path       = "path/to/your/video.mp4", 
  output_dir       = "path/to/output/frames", 
  fps              = 1,            # 1 frame per second
  format           = "jpg",        # photo format "jpg" or "png"
  camera_tz_offset = -5            # Timezone offset (e.g., -5 for Colombia)
)

# Run the extraction
ext <- extract(ext, verbose = TRUE)

# Verify that timestamps were stamped correctly
verify_timestamps(ext)

📁 Batch Folder Processing

To process all videos in a folder:

library(photoextractor)

# Create a folder extractor object
folder_ext <- FolderExtractor(
  folder_path      = "path/to/videos",
  output_dir       = "path/to/output",
  fps              = 1,           # 1 frame per second
  format           = "jpg",       # photo format "jpg" or "png"
  camera_tz_offset = -5           # Timezone offset (e.g., -5 for Colombia)
)

# Run batch extraction
folder_ext <- extract(folder_ext, verbose = TRUE)

# Verify that timestamps were stamped correctly
print(folder_ext@results)

Features

  • Metadata Preservation: Automatically reads video start time from EXIF/metadata.
  • Timestamp Stamping: Writes DateTimeOriginal, CreateDate, and filesystem timestamps to extracted frames.
  • Timezone Correction: Handles UTC offsets and camera clock corrections.
  • Organized Output: Automatically renames frames to include the source video name and zero-padded indices.
  • Modern OOP: Built using the new S7 object system for R.