Skip to content

Commit

Permalink
Update README.md
Browse files Browse the repository at this point in the history
  • Loading branch information
@Demmenie
Demmenie authored Jul 3, 2024
1 parent 6d67fd9 commit 0da476e
Showing 1 changed file with 6 additions and 6 deletions.
12 changes: 6 additions & 6 deletions README.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@
<a href="https://github.com/demmenie/videohash2/actions?query=workflow%3AWindows"><img alt="Build Status" src="https://github.com/demmenie/videohash2/workflows/Windows/badge.svg"></a>
<a href="https://github.com/demmenie/videohash2/actions?query=workflow%3AmacOS"><img alt="Build Status" src="https://github.com/demmenie/videohash2/workflows/macOS/badge.svg"></a>
<a href="https://pypi.org/project/videohash2/"><img alt="pypi" src="https://img.shields.io/pypi/v/videohash2.svg"></a>
<a href="https://pepy.tech/project/videohash?versions=1*&versions=2*&versions=3*"><img alt="Downloads" src="https://pepy.tech/badge/videohash/"></a>
<a href="https://pepy.tech/project/videohash?versions=1*&versions=2*&versions=3*"><img alt="Downloads" src="https://pepy.tech/badge/videohash"></a>
<a href="https://github.com/demmenie/videohash2/commits/main"><img alt="GitHub lastest commit" src="https://img.shields.io/github/last-commit/demmenie/videohash2?color=blue&style=flat-square"></a>
<a href="#"><img alt="PyPI - Python Version" src="https://img.shields.io/pypi/pyversions/videohash2?style=flat-square"></a>
</p>
Expand All @@ -19,17 +19,17 @@
# <img src="https://github.githubassets.com/images/icons/emoji/unicode/2b50.png" width="30"></img> Introduction

Videohash2 is a [Python package](https://www.udacity.com/blog/2021/01/what-is-a-python-package.html) for **detecting near-duplicate videos (Perceptual Video Hashing)**.
It can take any input video and generate a 64-bit equivalent hash value. Videohash is way more faster than comparing the imagehash values of individual [frames](https://en.wikipedia.org/wiki/Film_frame) of the video and more reliable than hashing [keyframes](https://en.wikipedia.org/wiki/Key_frame).
It can take any input video and generate a 64-bit equivalent hash value. Videohash is way faster than comparing the imagehash values of individual [frames](https://en.wikipedia.org/wiki/Film_frame) of the video and more reliable than hashing [keyframes](https://en.wikipedia.org/wiki/Key_frame).

The video-hash-values for identical or near-duplicate videos are the same or similar, implying that if the video is resized (upscaled/downscaled), [transcoded](https://medium.com/videocoin/what-is-video-transcoding-and-why-do-you-do-it-348a2610cefc), [watermark](https://en.wikipedia.org/wiki/Digital_watermarking) added/removed, [stabilized](https://link.springer.com/referenceworkentry/10.1007%2F978-0-387-78414-4_76), [color changed](https://en.wikipedia.org/wiki/Chrominance), [frame rate](https://www.techsmith.com/blog/frame-rate-beginners-guide/) changed, changed [aspect ratio](https://en.wikipedia.org/wiki/Aspect_ratio_(image)), [cropped](https://www.avs4you.com/blog/trim-cut-crop-avs4you/), [black-bars](https://en.wikipedia.org/wiki/Letterboxing_(filming)) added or removed, the hash-value should remain unchanged or not vary substantially.

### How the hash values are calculated

> - Every one second, a frame from the input video is extracted, the frames are shrunk to a 144x144 pixel square, a collage is constructed that contains all of the resized frames(square-shaped), the collage's [wavelet hash](https://fullstackml.com/wavelet-image-hash-in-python-3504fdd282b5)'s bit-list is the first bit-list that we use. The frames extracted are now stitched horizontally to each other, and finally divided into 64 equal sized images, the domiant color of these 64 images are detected and compared with a pre-defined pattern of dominant colors, if they match the bit is set else unset. So now we have two bitlist, finally we bitwise XOR these two bitlists. The XOR'ed output is used to generate the final 64 bit hash-value for the video. The bits are joined to form the 64 bit hash-value of the input value.
> - Every one second, a frame from the input video is extracted, the frames are shrunk to a 144x144 pixel square, a collage is constructed that contains all of the resized frames(square-shaped), the collage's [wavelet hash](https://fullstackml.com/wavelet-image-hash-in-python-3504fdd282b5)'s bit-list is the first bit-list that we use. The frames extracted are now stitched horizontally to each other, and finally divided into 64 equal sized images, the dominant color of these 64 images are detected and compared with a pre-defined pattern of dominant colours, if they match the bit is set else unset. So now we have two bitlists, finally we bitwise XOR these two bitlists. The XOR'ed output is used to generate the final 64 bit hash-value for the video. The bits are joined to form the 64 bit hash-value of the input value.
### When not to use Videohash

> - Videohash cannot be used to verify whether one video is a part of another (video fingerprinting). If the video is reversed or rotated by a substantial angle (greater than 10 degrees), Videohash will not provide the same or similar hash result, but you can always reverse the video manually and generate the hash value for reversed video.
> - Videohash cannot be used to verify whether one video is part of another (video fingerprinting). If the video is reversed or rotated by a substantial angle (greater than 10 degrees), Videohash will not provide the same or similar hash result, but you can always reverse the video manually and generate the hash value for reversed video.
### How to compare the video hash values stored in a database

Expand All @@ -41,7 +41,7 @@ The video-hash-values for identical or near-duplicate videos are the same or sim

To use this software, you must have [FFmpeg](https://ffmpeg.org/) installed. Please read [how to install FFmpeg](https://github.com/akamhy/videohash/wiki/Install-FFmpeg,-but-how%3F) if you don't already know how.

#### Install videohash
#### Install videohash2

Upgrade pip
```bash
Expand Down Expand Up @@ -150,4 +150,4 @@ Copyright (c) 2021-2022 Akash Mahanty. See
The VideoHash logo was created by [iconolocode](https://github.com/iconolocode). See [license](https://github.com/demmenie/videohash2/blob/main/assets/logo/LICENSE-LOGO) for details.

Videos are from NASA and are in the public domain.
> NASA copyright policy states that "NASA material is not protected by copyright unless noted".
> NASA copyright policy states that "NASA material is not protected by copyright unless noted".

0 comments on commit 0da476e

Please sign in to comment.