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ISCC-UNIT Content-Code Video

IEP: 0006
Title: ISCC-UNIT Condent-Code Video
Author: Titusz Pan tp@iscc.foundation
Comments: #11
Status: DRAFT
Type: Core
License: CC-BY-4.0
Created: {{ git_creation_date_localized }}
Updated: {{ git_revision_date_localized }}

!!! note

This document is a **DRAFT** contributed as input to 
[ISO TC 46/SC 9/WG 18](https://www.iso.org/committee/48836.html). The final version is 
developed at the International Organization for Standardization as
[ISO/DIS 24138](https://www.iso.org/standard/77899.html)

General

  1. The Content-Code Subtype Video (Video-Code) shall be a similarity hash of the input video.
  2. The Video-Code shall be robust against format conversions, scaling, compression, changes of framerate and minor edits.

Format

The Video-Code shall have the data format illustrated in Figure 8.

![Figure 8 - Data format of the Video-Code](images/iscc-iep-0006-f08-video-code.png) Figure 8 - Data format of the Video-Code

!!! example "EXAMPLE 1: 64-bit Video-Code in its canonical form:"

ISCC:EMA7KERCWROEVL6F

!!! example "EXAMPLE 2: 256-bit Video-Code in its canonical form:"

ISCC:EMD7KERCWROEVL6FU3SISZAZPJCBAZKXEZLZTSRQPGASTENCMSYFOAY

Inputs

The input for calculation of the Video-Code shall be the MPEG-7 video frame signatures, as specified in ISO/IEC 15938, from the original video data.

Outputs

Video-Code processing shall generate the following ISCC metadata output elements:

  1. iscc: the Video-Code in its canonical form (required);
  2. width: width of the original input video in number of pixels (optional);
  3. height: height of the original input video in number of pixels (optional);
  4. duration: duration of video in seconds (optional);
  5. fps: frames per second of the original video (optional);
  6. thumbnail: a thumbnail from the original video encoded as Data-URL (optional);
  7. Additional metadata extracted from the video (optional).

Processing

An ISCC processor shall pre-process the video file input as follows:

  1. Generate the MPEG-7 video signature at 5 frames per second.

An ISCC processor shall calculate the Video-Code as follows:

  1. For each of the 380 integer values of the MPEG-7 frame signature calculate its sum over all frames.
  2. Apply WTA hash to the resulting array of 380 integer values to calculate the ISCC-BODY of the Video-Code at the desired bit-length.

The normative behaviour of an ISCC processor in generating a Video–Code is specified only for the MPEG 7 video frame signature input. An implementation of the Video-Code algorithm shall be regarded as conforming to the standard if it creates the same Video-Code as the reference implementation for the same MPEG 7 video frame signature input.

!!! note "NOTE"

For further technical details see source-code in modules 
[code_content_video.py](https://github.com/iscc/iscc-core/blob/main/iscc_core/code_content_video.py)
and [wtahash.py](https://github.com/iscc/iscc-core/blob/main/iscc_core/wtahash.py) of the 
[reference implementation](https://github.com/iscc/iscc-core).