Video editing from Ruby on Rails, without FFmpeg on your machine.

What running FFmpeg from Rails usually costs

• The gems that wrap FFmpeg shell out to a binary your host has to provide, so a managed platform means a custom buildpack or a Docker image you now maintain.
• A render inside a request blocks a worker for as long as the encode takes, which is measured in whole seconds rather than milliseconds.
• Moving it to a background job helps the request and not the box: the encode still competes with the app for the same CPU.

Trim a clip from a background job

require 'net/http'
require 'json'

class KinopipeClient
  BASE = URI('https://kinopipe.com/api/v1')

  def initialize(key = ENV.fetch('KINOPIPE_API_KEY'))
    @headers = { 'Authorization' => "Bearer #{key}", 'Content-Type' => 'application/json' }
  end

  def run(tool, inputs, options = {})
    started = post("/tools/#{tool}", inputs: inputs, options: options)
    loop do
      job = get("/jobs/#{started.fetch('jobId')}")
      return job if %w[succeeded failed].include?(job['status'])
      sleep 2
    end
  end

  private

  def post(path, body)
    request(Net::HTTP::Post.new(URI.join(BASE.to_s + '/', path.delete_prefix('/')), @headers).tap { |r| r.body = body.to_json })
  end

  def get(path)
    request(Net::HTTP::Get.new(URI.join(BASE.to_s + '/', path.delete_prefix('/')), @headers))
  end

  def request(req)
    response = Net::HTTP.start(req.uri.hostname, req.uri.port, use_ssl: true) { |http| http.request(req) }
    JSON.parse(response.body)
  end
end

class TrimClipJob < ApplicationJob
  def perform(source_url)
    job = KinopipeClient.new.run(
      'trim-video',
      [{ id: 'main', url: source_url }],
      { start: 12, end: 48 },
    )
    raise job['errorMessage'] || 'the job did not finish' if job['status'] == 'failed'
    job.dig('result', 'output', 'downloadUrl')
  end
end

• Net::HTTP and JSON are in the standard library, so this adds no gem.
• An Active Storage blob needs a URL the service can fetch. A signed URL works; for a private file, upload it through /api/v1/uploads and use the media URL it returns.
• Send an Idempotency-Key header when you retry, and the retry returns the original job instead of paying for a second render.

FAQ