vsjs

VapourSynth for JavaScript.

Documentation

Vapoursynth Object

Constructor

This module allows you to create Vapoursynth objects with the following syntax:

let clip = vsjs.Vapoursynth(scriptContents, [scriptFilename]);

scriptContents is the actual contents of the script (as a buffer) which should be evaluated.

scriptFilename is the path of the script being evaluated. This is optional. See the vapoursynth C documentation for more information on vapoursynth's behavior if no filename is specified.

getInfo()

clip.getInfo();

Which returns some useful information about the clip:

{
  "height": 480,
  "width": 640,
  "numFrames": 1000,
  "fps": {
    "numerator": 24000,
    "denominator": 1001
  },
  "frameSize": 460800
}

frameSize indicates how large the buffer must be to fetch frames from this clip.

getFrame()

clip.getFrame(frameNumber, frameBuffer, callback);

frameNumber is the desired frame.

frameBuffer is the destination buffer. If no error occurs it will be populated with the frame data.

callback will be called when the frame data has been fetched with the following arguments:

callback(error, frameNumber, frameBuffer);

error is any exception encountered while getting the frame. If no exception was encountered it will be null.

frameNumber is the number of the fetched frame.

frameBuffer is the same buffer which was originally provided, but now with populated with frame data.

Example

const fs = require('fs');
const vsjs = require('vsjs');

const pathToScript = 'C:\\VapourSynth\\example.vpy';
const clip = vsjs.Vapoursynth(fs.readFileSync(pathToScript), pathToScript);

console.log(clip.getInfo());

clip.getFrame(0, Buffer.alloc(clip.getInfo().frameSize), (err, frameNumber, buffer) => {
    if (err) {
        console.log(err);
    } else {
        console.log(`buffer now contains frame ${frameNumber}`);
    }
});

Build

Install our dependencies:

> npm install

Then we go through the normal node-gyp process:

> node-gyp configure [--VS_SDK="C:/Vapoursynth/Install/sdk"]
> node-gyp build

To be honest I'm not sure if I've followed all the best practices for gyp builds or if the build will work on non-windows systems. If you have trouble building please try editing the binding.gyp or open an issue.

TODO

The vapoursynth dlls are no longer installed system-wide. This presents a challenge as they must be copied to wherever vsjs will be used...