teidesu-scripts/scripts/media/ffmpeg-clipper.ts

import { rm } from 'node:fs/promises'

import { $, question } from 'zx'

import { fileExists } from '../../utils/fs.ts'

let filename = await question('filename >')!
const startTs = await question('start timestamp >')
const endTs = await question('end timestamp >')
const outputFilename = await question('output filename [output.mp4] >') || 'assets/output.mp4'

if (filename[0] === '\'' && filename[filename.length - 1] === '\'') {
  filename = filename.slice(1, -1)
}

const ffprobe = await $`ffprobe -v error -show_entries stream=codec_type,codec_name,index:stream_tags=title,language -of json ${filename}`.json()

async function chooseStream(type: string, options: any[], allowNone = false) {
  console.log(`Found ${type} streams:`)
  for (let i = 0; i < options.length; i++) {
    const stream = options[i]
    console.log(`[${i + 1}] (${stream.codec_name}, ${stream.tags.language}) ${stream.tags.title}`)
  }

  if (allowNone) {
    console.log(`[0] No ${type}`)
  }

  const res = await question(`select ${type} >`) || '0'
  if (res === '0' && allowNone) {
    return null
  }

  const streamIndex = Number.parseInt(res)
  if (Number.isNaN(streamIndex) || streamIndex < 1 || streamIndex > options.length) {
    console.error('Invalid input')
    process.exit(1)
  }

  return streamIndex - 1
}

const allVideos = ffprobe.streams.filter(stream => stream.codec_type === 'video')
const allAudios = ffprobe.streams.filter(stream => stream.codec_type === 'audio')
const allSubtitles = ffprobe.streams.filter(stream => stream.codec_type === 'subtitle')

let videoStream: number | null = null
let audioStream: number | null = null
let subtitleStream: number | null = null

if (allVideos.length > 1) {
  videoStream = await chooseStream('video', allVideos)
} else if (allVideos.length > 0) {
  videoStream = 0
} else {
  console.error('No video streams found')
  process.exit(1)
}

if (allAudios.length > 1) {
  audioStream = await chooseStream('audio', allAudios)
} else if (allAudios.length > 0) {
  audioStream = 0
} else {
  console.warn('No audio streams found, proceeding without audio')
}

if (allSubtitles.length > 0) {
  subtitleStream = await chooseStream('subtitle', allSubtitles, true)
}

const args: string[] = [
  '-i',
  filename,
  '-c:v',
  'libx264',
  '-map',
  `0:v:${videoStream}`,
  '-c:v',
  'libx264',
]

if (audioStream !== null) {
  args.push('-map', `0:a:${audioStream}`)
}

if (subtitleStream !== null) {
  const filenameEscaped = filename.replace(/'/g, "'\\\\\\''")
  args.push('-vf', `format=yuv420p,subtitles='${filenameEscaped}':si=${subtitleStream}`)
} else {
  args.push('-vf', 'format=yuv420p')
}

if (audioStream !== null) {
  args.push('-c:a', 'libopus')

  if (allAudios[audioStream].codec_name === 'flac') {
    args.push('-b:a', '320k')
  }
}

args.push(
  '-ss',
  startTs!,
  '-to',
  endTs!,
  outputFilename,
)

if (await fileExists(outputFilename)) {
  const overwrite = await question('Output file already exists, overwrite? [y/N] >')
  if (overwrite?.toLowerCase() !== 'y') {
    process.exit(0)
  }

  await rm(outputFilename)
}

try {
  $.env.AV_LOG_FORCE_COLOR = 'true'
  await $`ffmpeg ${args}`
} catch (e) {
  process.exit(1)
}

const openDir = await question('open output directory? [Y/n] >')
if (!openDir || openDir?.toLowerCase() === 'y') {
  await $`open -R ${outputFilename}`
}