Download from youtubeDl with my custom video quality preference and downnload subtitles and convert vtt to srt with ffmpeg. Written in scala ammonite, so needs Ammonite to run it.

downloadWith-YoutubeDl.sc

import ammonite.ops._
import ujson.Js.Value
import upickle.default.{macroRW, ReadWriter => RW}
//import scala.math.Ordering.Implicits._

//https://transform.now.sh/json-to-scala-case-class
case class SubLanguage(ext: String, url: String)

object SubLanguage { // uPickle 0.7.1 needs these to parse the objects. Really ugly, maybe gson is better?
    implicit val rw: RW[SubLanguage] = macroRW
}

case class Formats(
//                      format: String,
                      format_id: String,
                      height: Int,
//                      width: Int,
//                      preference: String,
//                      manifest_url: String,
//                      url: String,
//                      protocol: String,
//                      http_headers: HttpHeaders,
                      ext: String,
//                      vcodec: String,
                      tbr: Int, // total bitrate
                      //                      acodec: String,
//                      fps: String
                  )  extends Ordered[Formats]
{
    def compareValueFormatId = {
        val pattern = """.*-(\d+)""".r
        format_id match {
            case pattern(number) => -number.toInt
            case  _ => 0
        }
    }
    def compare(that: Formats): Int = {
        val aTuple: (Int, Int, Int, Int) = (this.height, this.tbr, formatPreference(this.ext), this.compareValueFormatId)
        val bTuple: (Int, Int, Int, Int) = (that.height, that.tbr, formatPreference(that.ext), that.compareValueFormatId)
        implicitly[Ordering[Tuple4[Int, Int, Int, Int]]].compare(aTuple, bTuple)
    }
}

object Formats {
    implicit val rw: RW[Formats] = macroRW
}

// Upickle fails with AbortException if items are missing
case class Subtitles(da: Seq[SubLanguage]/*, en: Seq[SubLanguage]*/)

object Subtitles {
    implicit val rw: RW[Subtitles] = macroRW
}

case class Thumbnails(id: String, url: String)

object Thumbnails {
    implicit val rw: RW[Thumbnails] = macroRW
}


//case class HttpHeaders(
//"Accept-Encoding": String,
//"User-Agent": String,
//"Accept-Charset": String,
//"Accept-Language": String,
//Accept: String,
//Cookie: String
//)

case class YoutubeDl
(
    height: Int,
//    playlist: String,
    title: String,
    formats: Seq[Formats],
//    description: String,
//    url: String,
//    thumbnails: Seq[Thumbnails],
//    http_headers: HttpHeaders,
    fps: String,
    display_id: String,
    format_id: String,
//    extractor: String,
//    duration: Double,
//    preference: String,
//    manifest_url: String,
//    acodec: String,
//    protocol: String,
//    id: String,
//    vcodec: String,
//    requested_subtitles: String,
//    ext: String,
//    subtitles: Subtitles,
//    webpage_url_basename: String,
//    playlist_index: String,
//    upload_date: String,
//    format: String,
//    webpage_url: String,
//    width: Int,
//    timestamp: Int,
//    thumbnail: String,
//    extractor_key: String,
    tbr: Int
)
object YoutubeDl{
    implicit val rw: RW[YoutubeDl] = macroRW
}


// Also in AlexFunctions, todo import it instead
def basename(d: Path) = {
    // OR d.name.split("\\.(?=[^\\.]+$)")(0)
    val n = d.name
    val extSize = d.ext.size
    val extSizeWithPeriod = if (extSize > 0) extSize + 1 else 0
    d.name.substring(0, d.name.size - extSizeWithPeriod)
}

def convertSubtitlesAllVttToSrt(path: Path): Unit = {
    ls(path) |? {
        _.ext == "vtt"
    } | { f =>
        val srtName = basename(f) + ".srt"
        if (!exists(path / srtName)) {
            %("ffmpeg.exe", "-i", f.name, basename(f) + ".srt")(path)
        }
        rm(f)
    }
}

// Unused
def getBestFormatIdWithuJsonExample(jsonString: String): String = {
    val tbr="tbr"
    val ext="ext"

    val json: Value = ujson.read(jsonString)
    val formats: ujson.Js.Arr = json("formats").arr
    var best : Option[ujson.Js] = None
    for (current <- formats.value) {
        if (best.isEmpty) {
            best = Some(current)
        } else {
            val theBest=best.get
            if (current(tbr).num > theBest(tbr).num ||
                (current(tbr).num == theBest(tbr).num &&
                    current(ext).str == "mp4" && theBest(ext).str != "mp4") ) {
                best = Some(current)
            }
        }

    }
    best.get("format_id").str
}

def formatPreference(ext: String): Int = {
    // 3gp, aac, flv, m4a, mp3, mp4, ogg, wav, webm
    ext match {
        // video containers
        case "mkv" => 10 // not possible in youtube-dl
        case "mp4" => 9
        case "webm" => 8
        case "flv" => 7
        case "3gp" => 6
        // audio only
        case "m4a" => 5
        case "aac" => 4
        case "ogg" => 3
        case "mp3" => 2
        case "wav" => 1
        case _ => 0
    }
}
def selectBestFormat(a: Formats, b: Formats) = {
    if (a.compare(b) >= 0) a else b
}
def getBestFormatId(path: Path, videoUrl: String): String = {
    val jsonString = %%("youtube-dl", "-J", videoUrl)(path).out.lines(0)
    val json = upickle.default.read[YoutubeDl](jsonString) // upickle variant
    val formats: Seq[Formats] = json.formats
    if (formats.isEmpty) ""
    else formats.foldLeft(formats.head)(selectBestFormat).format_id
}

def downloadVideo(path: Path, videoUrl: String): Unit = {
    //    --download-archive : I think it zips and keeps all intermediaries. Might be needed if ffmpeg corrupts stream
    val formatId = getBestFormatId(path, videoUrl)
    val p = %%(s"youtube-dl --all-subs --fixup warn -f $formatId $videoUrl".split(" ").toVector)(path)
    //    rm(path/"*temp.mp4") // HowTo, maybe: ls(path) |? {_.name.endsWith("temp.mp4"} | rm
    println(p.out.lines.mkString("\n"))
    if (p.exitCode == 0) {
        println("Success")
        convertSubtitlesAllVttToSrt(path)
    } else {
        println("Failed: " + p.err.lines.mkString("\n"))
    }
}

val filmPath = Path("""m:\Film""")
val serierJul = filmPath / "Serier Jul"

downloadVideo(serierJul / "MoviePath", "https://www.youtube.com/watch?v=_JUwcv7dUQI")