shared.md

Shared API

ComplexFilter

import {ComplexFilter} from 'video-renderer/browser';
// or
import {ComplexFilter} from 'video-renderer/node';

An object, representing a filter that can be applied to one or more inputs. For example, the extract alpha filter looks like:

const filter: ComplexFilter[] = [
  // ensure video is even number of pixels heigh/wide
  // because mp4 requires this
  {
    inputs: ['0'],
    name: 'scale',
    args: {
      w: 'trunc(iw/2)*2',
      h: 'trunc(ih/2)*2',
    },
    outputs: ['extract_alpha_scaled'],
  },
  // create 2 copies of video
  {
    inputs: ['extract_alpha_scaled'],
    name: 'split',
    args: {},
    outputs: ['extract_alpha_scaled_1', 'extract_alpha_scaled_2'],
  },
  // [mask] set format to rgba
  {
    inputs: ['extract_alpha_scaled_2'],
    name: 'format',
    args: {
      pix_fmts: 'rgba',
    },
    outputs: ['extract_alpha_rgba'],
  },
  // [mask] generate alpha mask
  {
    inputs: ['extract_alpha_rgba'],
    name: 'alphaextract',
    args: {},
    outputs: ['extract_alpha_extracted'],
  },
  // [original] pad to allow space at the bottom for the alpha mask
  {
    inputs: ['extract_alpha_scaled_1'],
    name: 'pad',
    args: {h: 'ih*2'},
    outputs: ['extract_alpha_padded'],
  },
  // overlay the alpha mask on the space created at the bottom of the original video
  {
    inputs: ['extract_alpha_padded', 'extract_alpha_extracted'],
    name: 'overlay',
    args: {x: '0', y: 'overlay_h'},
  },
];