Transflow

Set of tools for transferring optical flow from one media to another.

This tool extracts optical flow as a dense velocity field from a video input (file or stream) and applies it to an image, a video file or stream, for creative purposes. Multiple techniques can be used, various parameters can be tuned to precisely craft visual effects directly from raw raster data. Here is how it looks (click to view in full resolution):

Flow Source	Pixmap Source	Result

Getting Started

Prerequisites

You'll need a working installation of Python 3. You'll also need FFmpeg binaries, available in PATH, the ffmpeg -version command should work.

Basic Installation

The process should be straightforward.

1. Download the latest release
2. Install it with pip:

   pip install ~/Downloads/transflow-1.11.0.tar.gz

Alternative Installation

If you want to access the code.

1. Clone or download this repository:

   git clone https://github.com/ychalier/transflow.git
   cd transflow

2. Install requirements:

   pip install -r requirements.txt

Usage

The alias transflow represents either python -m transflow or python transflow.py, depending on the chosen installation method. The simplest process consists in taking the motion from a video file and applying it to an image:

transflow flow.mp4 -p image.jpg -o output.mp4

If your are not too familiar with the command line, you can use the graphical user interface (GUI) to set parameters interactively. You can run the GUI with:

transflow gui

For more details, see USAGE.md.

Examples

Basic Transfer

transflow assets/River.mp4 -p assets/Deer.jpg -Oo out/ExampleBasic.mp4

Random Reset

transflow assets/River.mp4 -d forward -p assets/Frame.png -r random 0.5 -m assets/Mask.png -Oo out/ExampleResetRandom.mp4

Progressive Introduction

transflow assets/Train.mp4 -p assets/Train.mp4 -i border-right:1 -l 0 introduction --background black -Oo out/ExampleIntroduction.mp4"

Sticky Texture

transflow assets/Train.mp4 -p assets/Train.mp4 -p assets/Frame.png 1 -l 0 static -l1 -e -Oo out/ExampleStickyTexture.mp4

Additional Resources

This repository also contains two other versions of this program:

• in the extra/cpp folder, a C++ version using OpenCV to transfer the flow from one webcam to another,
• in the extra/www folder, a WebGL version that emulates the effect in a web browser; a version is hosted on chalier.fr/transflow.

There are also other modules (in the extra folder):

• viewflow, for visualizing and inspecting optical flow in a video player setting,
• control, for generating alteration images (see Pixmap Alteration).

Contributing

Contributions are welcomed. Do not hesitate to submit a pull request with your changes! Submit bug reports and feature suggestions in the issue tracker.

License

This project is licensed under the GPL-3.0 license.