Katna documentation

Katna automates the boring, error prone task of videos key/best frames extraction and manual time consuming task of image cropping.

Katna is divided into two modules namely video and image.

Video Module:

This module handles the task(s) for key frame(s) extraction.

Key-frames are defined as the representative frames of a video stream, the frames that provide the most accurate and compact summary of the video content.

Frame extraction and selection criteria

  1. Frame that are sufficiently different from previous ones using absolute differences in LUV colorspace
  2. Brightness score filtering of extracted frames
  3. Entropy/contrast score filtering of extracted frames
  4. K-Means Clustering of frames using image histogram
  5. Selection of best frame from clusters based on and variance of laplacian (image blur detection)

Image Module:

This module handles the task(s) for smart cropping.

The Smart crop feature tries to automatically identify important image areas where the user will focus more and tries to retain it while cropping. For a given input cropping dimension/final output image size, following selection and filtering criteria are used.

Crop selection and filtering criteria

  1. Edge, saliency and Face features.
  2. Distance of crop from Image edge, Rule of third
  3. Crop filters. At the moment only text filter is supported. Text filter ensures that cropped rectangle contains text, also it ensures that texts present is not abruptly cropped.

Supported Video and image file formats

All the major video formats like .mp4,.mov,.avi etc and image formats like .jpg, .png, .jpeg etc are supported.

Additional selection features and retention filters are in development pipeline.

Indices and tables