yaffu - Yet Another FFmpeg Util

Programmatically combine videos into a merged output with a dynamic layout.

Dependencies

• FFmpeg
• Node 20

Install

npm install yaffu@latest

Example

Run the example/grid.js script which demos genericCombine (mixes all audio and stacks all video on a centered grid):

git clone https://github.com/erwinv/yaffu
cd yaffu

corepack enable
corepack install

# build modules
pnpm install
pnpm build

# run examples
cd example
pnpm install
node grid.js

Output (1080p)

grid_layout.mp4

Using genericCombine is as simple as:

import { ffmux, genericCombine } from 'yaffu'

const inputPaths = [
  //...
]
await ffmux(genericCombine(inputPaths, 'combined.mp4'))

Timeline Example

Suppose audio/video inputs are given with the following timeline:

        0    5    10   15   20   25   30   35   40   45   50   55   60   65   70   75   80
--------|----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|--
alice        [===========]                 [=======================================]
bob             [===========]                   [========================]
charlie            [===========]                     [==============]
david                 [===========]                       [====]
screen                                [=======================================]

See example/timeline.js to see how to encode the above timeline using the API.

Output (720p)

timeline.mp4

API

High-level API

• mixAudio downmixes and mixes all input audio to stereo
• compositeGrid stacks all video input on a grid layout (max 16 or 4x4 grid)
• compositePresentation main tile (presentation) on the left, vertically stacked tiles on the right (max 4)
• genericCombine is a convenient wrapper that does both mixAudio and compositeGrid

Low-level API

• FilterGraph filter graph builder class
• ffmux executes the filter graph and muxes to the defined output
• ffconcatDemux concatenates all input files using FFmpeg's concat demuxer
• ffprobe probe media file's metadata

import { FilterGraph, ffmux } from 'yaffu'

const inputPaths = [
  //...
]

const graph = new FilterGraph(inputPaths)

// build filter graph by piping streams through filters to output streams
graph
  .pipe(['0:a', '1:a'], ['aout']) // input stream ids, output stream ids
  .filter('amix', [], { normalize: 0 }) // filter name, direct options, key-value options
  .filter('dynaudnorm') // filter with no opts (use default opts)

// map stream/s to output file
graph.map(['aout'], 'output.aac')

// run the muxer
await ffmux(graph)