Rohring-video-generator NPM

Rohring Video Generator

Rohring Video Generator is a React-based package that converts uploaded images into an MP4 video using FFmpeg. The processed video can be downloaded as an MP4 file.

Features

Upload multiple images to generate a slideshow video.
Automatic resizing of images to fit within a 1920x1080 resolution.
Adds custom text descriptions to each image.
Uses FFmpeg for video processing in the browser.
Generates a downloadable MP4 video.

Getting Started

Prerequisites

Ensure you have Node.js installed on your system. The following dependencies are required:

@ffmpeg/ffmpeg for handling video generation.
file-saver for downloading the generated video.
framer-motion for animations (if used in the UI).

Installation

Clone the repository and install dependencies:

git clone https://github.com/webteamrohring/rohr-video-generator
cd rohr-video-generator
npm install

Usage

Download and Use the Package in Any Application

To install the package, run:

npm install rohring-video-generator

Available Scripts

`npm start`

Runs the package in development mode.

`npm test`

Launches the test runner.

`npm run build`

Builds the package for production.

How It Works

The user uploads images along with optional text descriptions.
Images are resized to a maximum resolution of 1920x1080.
Each image is placed on a black background with the text description below.
Images are processed using FFmpeg and stored in its virtual filesystem.
FFmpeg executes commands to generate a video slideshow.
The generated video is available for download as an MP4 file.

Video Generation Process

Load FFmpeg and initialize the virtual filesystem.
Resize images while maintaining their aspect ratio.
Overlay text descriptions at the bottom of each image.
Store images as PNG files in FFmpeg's memory.
Generate a video using the following FFmpeg command:

ffmpeg -framerate 0.5 -start_number 0 -i img%d.png -vf "scale='min(1080,iw)':'min(1024,ih)',pad=1080:1024:(1080-iw)/2:(1024-ih)/2:black" -c:v libx264 -pix_fmt yuv420p -r 30 output.mp4

Read and download the generated MP4 file.

Example Code

import { FFmpeg } from "@ffmpeg/ffmpeg";
import { saveAs } from "file-saver";

export async function generateVideoFromImages(images, descriptions, setLoading) {
  if (images.length === 0) {
    alert("Please upload images first.");
    return;
  }

  setLoading(true);
  const ffmpeg = new FFmpeg();
  await ffmpeg.load();

  for (let i = 0; i < images.length; i++) {
    const img = await createImageBitmap(images[i]);
    const canvas = document.createElement("canvas");
    const ctx = canvas.getContext("2d");

    const maxWidth = 1920;
    const maxHeight = 1080;
    const textHeight = 200;
    let width = img.width;
    let height = img.height;

    if (width > maxWidth || height > maxHeight) {
      const scaleFactor = Math.min(maxWidth / width, maxHeight / height);
      width = Math.floor(width * scaleFactor);
      height = Math.floor(height * scaleFactor);
    }

    canvas.width = width;
    canvas.height = height + textHeight;

    ctx.fillStyle = "black";
    ctx.fillRect(0, 0, canvas.width, canvas.height);

    ctx.drawImage(img, 0, 0, width, height);

    ctx.font = "30px Arial";
    ctx.fillStyle = "white";
    ctx.textAlign = "center";
    
    const textWidth = Math.min(800, canvas.width - 40);
    const words = (descriptions[i] || "").split(" ");
    let line = "";
    const lines = [];
    const lineHeight = 24;

    for (let word of words) {
      let testLine = line + word + " ";
      let metrics = ctx.measureText(testLine);
      if (metrics.width > textWidth) {
        lines.push(line);
        line = word + " ";
      } else {
        line = testLine;
      }
    }
    lines.push(line);
    
    const textYStart = height + (textHeight - lines.length * lineHeight) / 2;
    
    lines.forEach((line, index) => {
      ctx.fillText(line, canvas.width / 2, textYStart + index * lineHeight);
    });

    const resizedBlob = await new Promise((resolve) =>
      canvas.toBlob(resolve, "image/png")
    );

    const fileData = await resizedBlob.arrayBuffer();
    ffmpeg.writeFile(`img${i}.png`, new Uint8Array(fileData));
  }

  await ffmpeg.exec([
    "-framerate", "0.5",
    "-start_number", "0",
    "-i", "img%d.png",
    "-vf", "scale='min(1080,iw)':'min(1024,ih)',pad=1080:1024:(1080-iw)/2:(1024-ih)/2:black",
    "-c:v", "libx264",
    "-pix_fmt", "yuv420p",
    "-r", "30",
    "output.mp4",
  ]);

  const data = await ffmpeg.readFile("output.mp4");
  const fileName = new Date().toISOString().replace(/[:.]/g, "-") + ".mp4";

  const videoBlob = new Blob([data.buffer], { type: "video/mp4" });
  saveAs(videoBlob, fileName);

  setLoading(false);
}