split-video-on-silences.js

// Author: Taylor Bell
// Name: Split video on silences
// Description: detects video silences over a threshold length and deletes the silences

// note: run `brew install ffmpeg` and `brew link ffmpeg` then in ScriptKit run "sync path from terminal to Kit.app"

import "@johnlindquist/kit"
const replaceAll = await npm('just-replace-all')    
const numbers = await npm('numbers-in-string')
const seconds = await npm('seconds-to-timestamp')
const chunk = await npm('chunk')
const leadingzero = await npm('leadingzero')
const escape = await npm('escape-path-with-spaces')

const MINUTES_OF_SILENCE = 3
const silenceInSeconds = MINUTES_OF_SILENCE * 60

/*
*  Highlight the long video we are taking clips out of in Finder
*/
let longVideoFile = await getSelectedFile()

cd(path.dirname(longVideoFile))

let filename = longVideoFile.split(path.dirname(longVideoFile)+'/')

/*
* Detect silences in long video file and parse timestamps
*/
await(hide)

let { stdout, stderr } =
  await $`ffmpeg -i ${longVideoFile} -af silencedetect=noise=-40dB:d=${silenceInSeconds} -f null -`

let termOutput = stderr.split(/\r\n|\n\r|\n|\r/)

let detectedSilenceLines = termOutput.filter(x => x.includes('[silencedetect'))


let timestamps = chunk([0, ...detectedSilenceLines.map(x => x.split(': ')[1].split(' ')[0]).map(x => numbers(x)).flat()])

let cutsToMake = timestamps.map((time, index) => {
    if (time[1] === undefined) {
        return {
            from: seconds(time[0]),
            desc: `part${leadingzero(index+1, 2)}`
        }
    }

    return {
        from: seconds(time[0]),
        to: seconds(time[1]),
        desc: `part${leadingzero(index+1, 2)}`
    }
}).filter(x => !(x.from === x.to))

let silentCutsToMake = cutsToMake.map((time, index) => {
    if (index+1 == cutsToMake.length) {
        return {}
    }
    
    return {
        from: time['to'],
        to: cutsToMake[index+1]['from'],
        desc: `silent_part${leadingzero(index+1, 2)}`
    } 
}).slice(0,-1).filter(x => !(x.from === x.to))


/*
 * Split video clips, cutting out silences 
 */

for (let cut of cutsToMake) {
  let clipFileName = `${replaceAll(cut.desc, ' ', '_')}.mp4`

  await exec(`ffmpeg -i "${longVideoFile}" -c copy -ss ${cut.from} ${cut.to ? `-to ${cut.to}`: ''} ${clipFileName}`)
}

/**
 * Create silent videos just in case stuff happens
 */

 for (let cut of silentCutsToMake) {
    let clipFileName = `${replaceAll(cut.desc, ' ', '_')}.mp4`
  
    await exec(`ffmpeg -i "${longVideoFile}" -c copy -ss ${cut.from} ${cut.to ? `-to ${cut.to}`: ''} ${clipFileName}`)
  }