yt

#!/usr/bin/env bash

yt() {
  local usage="NAME
      yt  -  fine-tuning the use of youtube-dl / yt-dlp. Download music or video from e.g.
      YouTube,  Soundcloud,  Instagram,  Facebook.  For a full list of supported sites and
      services, see https://github.com/yt-dlp/yt-dlp/blob/master/supportedsites.md.

SYNOPSIS
      yt [OPTIONS] -- [URL] [URL...]

DESCRIPTION
      yt is a bash function that  optimizes the use of  yt-dlp  for audio and  videophiles
      with comprehensive and customizable presets, empirically tested on multiple streams.
      Maintains a  download archive,  to prevent duplicates when  periodically downloading
      YouTube playlists or Soundcloud sets.  Parses title  (\"%(artist)s - %(title)s\")  and
      retrieves a thumbnail, and injects these into file metadata.  Adds the url id of the
      source to the filename, and attempts to bypass geographical restrictions.

OPTIONS
      -h, --help
            Print this help text and exit.

      -s
            Enable silent mode (send stdout to /dev/null).

      -S
            Enable sequential mode.  Default behaviour: parallel mode.  The MAXPROCS (env)
            var sets parallelism  (default 4).  To download YouTube playlists in parallel,
            use e.g. \"yt -v -- \$(yt-dlp --get-id --flat-playlist <playlist-url>)\".

      -f
            Force download, even when already recorded in --download-archive.

      -v
            Enable video mode. Defaults to audio mode. Only mono and stereo are supported.

      -c
            Fetch space separated  URLs from clipboard,  additional to the manually passed
            URLs. Auto-enables when no URLs are manually passed.

      -D POSIX_PATH
            Set the destination path.  Used for both the (intermediate) output and for the
            download archive. Defaults to  \"~/Music/yt\"  and  \"~/Movies/yt\"  for audio and
            video mode respectively. Override defaults with YT_MUSIC_DIR and YT_VIDEO_DIR.

      -p
            Enable playlist mode. When a video URL contains a reference to a playlist, the
            whole playlist will be  downloaded.  Will only download URLs that have not yet
            been recorded in the download archive.

      -k
            Keep original audio additionally.  In most cases, this will keep e.g. OPUS for
            YouTube, or LAME MP3 / WAV for Soundcloud URLs.  Ignored when -v is specified.

      -a KBITS_PER_SECOND
            Set the output audio bitrate. Defaults to 256kbit/s.

      -r HERTZ
            Set the output audio sampling rate. Defaults to 44100Hz.

      -P PIXELS
            Set the maximum pixels of the video output.  Ignored when -v is not specified.
            Defaults to 1920px. Constraint is dropped when no formats comply. For portrait
            and landscape videos,  this corresponds to the  height and width respectively.

      -F FRAMES
            Set the maximum framerate in frames per second. Defaults to 42. Ignored when
            -v is not specified. Constraint is dropped when no formats comply.

      -m
            Use MP4 when merging audio/video streams, keeping video codecs if possible and
            converting audio to 256kbit/s AAC (resolving full 44.1KHz stream). If no merge
            is needed,  the (single) source file is kept  and no conversion is  performed.
            Default behaviour:  copy downloaded audio/video streams into an MKV container,
            using OPUS audio codec and  VP9 video codec for small filesizes.  Ignored when
            -v is not specified. For YouTube this will yield a maximum resolution of 1080.
            Sometimes,  AV1 streams will only be available up to a certain resolution.  In
            this case, specifying -M might yield higher resolution.

      -M
            Prefer the older AVC codec over AV1. Results in bigger file-sizes, but  better
            playback compatibility. Ignored when -v and -m are not specified.

      -H
            Prefer HDR streams. Tested on YouTube videos. Overrides -m.

      -A
            Embed all available audio streams. Ignored when -v is not specified.

BSD 3-Clause License

Copyright (c) 2019, ddelange
All rights reserved."
  local OPTIND  # https://stackoverflow.com/a/16655341/5511061
  local SILENT=false
  local PARALLEL=true
  local PARALLELISM=${MAXPROCS:=4}
  local VIDEO_MODE=false
  local CLIPBOARD=false
  local CUSTOM_DESTINATION=
  local PLAYLIST=false
  local KEEP_AUDIO=false
  local AUDIO_MULTISTREAMS=false
  local FORCE=false
  local CUSTOM_AUDIO_BITRATE=false
  local AUDIO_BITRATE=256
  local AUDIO_SAMPLING_RATE=44100
  local MAX_PIXELS=1280  # Youtube Shorts are 720x1280 (portrait)
  local MAX_FPS=42
  local MP4=false
  local AVC=false
  local HDR=false
  local URLS=()
  local CODECS=$(ffmpeg -codecs -hide_banner)
  if echo ${CODECS} | grep -q 'aac_at'; then
    local ENCODER='aac_at'
  elif echo ${CODECS} | grep -q 'libfdk_aac'; then
    local ENCODER='libfdk_aac'
  else
    local ENCODER='aac'
  fi

  # TODO
  # ~$ sudo yt -U
  # sudo: yt: command not found

  # TODO
  # Support playlists in parallel https://github.com/ytdl-org/youtube-dl/issues/3746#issuecomment-446694257

  if [ "$1" == "--help" ] || [ "$1" == "-h" ]; then
    set -- "-h"
  fi
  while getopts ":hUsSfvcD:pka:r:P:mMAH" opt; do
    case $opt in
      h)
        echo "$usage"
        return;;
      s)
        SILENT=true
        ;;
      S)
        PARALLEL=false
        ;;
      f)
        FORCE=true
        ;;
      v)
        VIDEO_MODE=true
        ;;
      c)
        CLIPBOARD=true
        ;;
      D)
        CUSTOM_DESTINATION="$OPTARG"
        ;;
      p)
        PLAYLIST=true
        ;;
      k)
        KEEP_AUDIO=true
        ;;
      a)
        case $OPTARG in
          ''|*[!0-9]*)
            echo "-a: specify bitrate as integer. Type \"yt -h\" for more info."
            return
            ;;
          *)
            if [ $OPTARG -gt 1411 ]; then
              echo "-a: bitrate should not be greater than 1411kbit/s."
              return
            fi
            CUSTOM_AUDIO_BITRATE=true
            AUDIO_BITRATE=$OPTARG
            ;;
        esac
        ;;
      r)
        case $OPTARG in
          ''|*[!0-9]*)
            echo "-r: specify sampling rate as integer. Type \"yt -h\" for more info."
            return
            ;;
          *)
            if [ $OPTARG -gt 48000 ]; then
              echo "-r: sampling rate should not be greater than 48000Hz."
              return
            fi
            AUDIO_SAMPLING_RATE=$OPTARG
            ;;
        esac
        ;;
      P)
        case $OPTARG in
          ''|*[!0-9]*)
            echo "-P: specify pixels as integer. Type \"yt -h\" for more info."
            return
            ;;
          *)
            if [ $OPTARG -lt 144 ]; then
              echo "-P: pixels should not be less than 144px."
              return
            fi
            MAX_PIXELS=$OPTARG
            ;;
        esac
        ;;
      F)
        case $OPTARG in
          ''|*[!0-9]*)
            echo "-F: specify fps as integer. Type \"yt -h\" for more info."
            return
            ;;
          *)
            if [ $OPTARG -lt 20 ]; then
              echo "-F: fps should not be less than 20."
              return
            fi
            MAX_FPS=$OPTARG
            ;;
        esac
        ;;
      m)
        MP4=true
        ;;
      M)
        AVC=true
        ;;
      H)
        HDR=true
        ;;
      A)
        AUDIO_MULTISTREAMS=true
        ;;
      \?)
        echo "Invalid option: -$OPTARG"
        return;;
      :)
        echo "Option -$OPTARG requires an argument. Type \"yt -h\" for more info."
        return;;
    esac
  done
  shift "$((OPTIND - 1))"
  # get remaining arguments, treated as urls
  while test $# -gt 0; do
    URLS+=("$1")
    shift
  done

  if $CLIPBOARD || [ ${#URLS[@]} -eq 0 ]; then
    URLS+=($(pbpaste))
  fi
  if ! $SILENT; then
    echo "${URLS[@]}"
  fi

  # set paths
  if [[ $CUSTOM_DESTINATION ]]; then
    local destination="$CUSTOM_DESTINATION"
  else
    if $VIDEO_MODE; then
      local destination="${YT_VIDEO_DIR:-~/Movies/yt}"
    else
      local destination="${YT_MUSIC_DIR:-~/Music/yt}"
    fi
  fi
  # ensure trailing slash on $destination
  local len=$((${#destination}-1))
  if [ "${destination:len}" != "/" ]; then
    destination="${destination}/"
  fi

  # BASE_OPTIONS
  local BASE_OPTIONS=(--geo-bypass --ignore-config -i -F --no-simulate)
  local output_filename="${destination}%(title).200s %(id)s.%(ext)s"
  local download_archive="${destination}downloaded.txt"
  BASE_OPTIONS+=(-o "$output_filename")
  if ! $FORCE; then
    BASE_OPTIONS+=(--download-archive "$download_archive")
  else
    BASE_OPTIONS+=(--force-overwrites)
  fi
  BASE_OPTIONS+=(--add-metadata --metadata-from-title "%(artist)s - %(title)s")
  if $PLAYLIST; then
    BASE_OPTIONS+=(--yes-playlist)
  else
    BASE_OPTIONS+=(--no-playlist)
  fi


  # DOWNLOAD_OPTIONS
  local audio_selector='bestaudio[acodec=opus]/bestaudio[container*=dash]/bestaudio'
  local px_spec="[height<=${MAX_PIXELS}][fps<=${MAX_FPS}]"
  local hdr_selector="bestvideo[vcodec~='(vp09|vp9)']${px_spec}/bestvideo${px_spec}/bestvideo"
  local avc_selector="bestvideo[vcodec^=avc]${px_spec}/bestvideo"'[vcodec!^=vp]'"${px_spec}/bestvideo[ext=mp4]"
  local av1_selector="bestvideo[vcodec^=av01]${px_spec}/bestvideo[vcodec^=av]${px_spec}/bestvideo"'[vcodec!^=vp]'"${px_spec}/bestvideo[ext=mp4]"
  local default_video_selector="bestvideo[vcodec~='(vp09.00|vp9)']${px_spec}/bestvideo[vcodec!=vp09.02]${px_spec}/bestvideo${px_spec}/bestvideo"
  local fallback_video_selector="best${px_spec}/best"
  if $VIDEO_MODE; then
    if $AUDIO_MULTISTREAMS; then
      audio_selector='mergeall[vcodec=none]'
    fi
    if $HDR; then
      local DOWNLOAD_OPTIONS=(--merge-output-format mkv -f "(${hdr_selector})+(${audio_selector})/${fallback_video_selector}")
    elif $MP4; then
      local DOWNLOAD_OPTIONS=(--merge-output-format mp4 --postprocessor-args "Merger:-threads 0 -vcodec copy -b:a ${AUDIO_BITRATE}k -ar ${AUDIO_SAMPLING_RATE} -acodec ${ENCODER} -cutoff 20000")
      if [ $MAX_PIXELS -gt 1920 ] && ! $SILENT; then
        echo "Maximum resolution is set to ${MAX_PIXELS}, and -m is present. Downloads will be limited to max 1080p on sites that don't provide higher resolution video streams in MP4 container (e.g. YouTube)."
      fi
      if $AVC; then
        DOWNLOAD_OPTIONS+=(-f "(${avc_selector})+(${audio_selector})/${fallback_video_selector}")
      else
        DOWNLOAD_OPTIONS+=(-f "(${av1_selector})+(${audio_selector})/${fallback_video_selector}")
      fi
    else
      local DOWNLOAD_OPTIONS=(--merge-output-format mkv -f "(${default_video_selector})+(${audio_selector})/${fallback_video_selector}")
    fi
    if $AUDIO_MULTISTREAMS; then
      DOWNLOAD_OPTIONS+=(--audio-multistreams)
    fi
    DOWNLOAD_OPTIONS+=(--embed-subs --sub-langs all,-live_chat --sub-format "srt/best")
  else
    local DOWNLOAD_OPTIONS=(--embed-thumbnail --audio-format m4a --audio-quality ${AUDIO_BITRATE}k --postprocessor-args "ExtractAudio:-ar ${AUDIO_SAMPLING_RATE} -acodec ${ENCODER} -cutoff 20000" -x -f "${audio_selector}/best")
    if $KEEP_AUDIO; then
      DOWNLOAD_OPTIONS+=(-k)
    fi
  fi

  # debug the command (non-parallel)
  # a=(yt-dlp "${BASE_OPTIONS[@]}" "${DOWNLOAD_OPTIONS[@]}" "${URLS[@]}")
  # echo ${a[@]}

  if $PARALLEL; then
    if $SILENT; then
      printf "\"%s\"\n" "${URLS[@]}" | xargs -n 1 -P ${PARALLELISM} -I{} yt-dlp "${BASE_OPTIONS[@]}" "${DOWNLOAD_OPTIONS[@]}" -- "{}" > /dev/null
    else
      printf "\"%s\"\n" "${URLS[@]}" | xargs -n 1 -P ${PARALLELISM} -I{} yt-dlp "${BASE_OPTIONS[@]}" "${DOWNLOAD_OPTIONS[@]}" -- "{}"
    fi
  else
    if $SILENT; then
      yt-dlp "${BASE_OPTIONS[@]}" "${DOWNLOAD_OPTIONS[@]}" -- "${URLS[@]}" > /dev/null
    else
      yt-dlp "${BASE_OPTIONS[@]}" "${DOWNLOAD_OPTIONS[@]}" -- "${URLS[@]}"
    fi
  fi
}

# yt -P 1440 -v -H ESxIaJWUtAs # will download 1440p mkv
# yt -P 1440 -v -m ESxIaJWUtAs # will download 1080p mp4
# yt -P 1440 -v -m 75fEhQlc9h4 # will download 480p mp4 av01
# yt -P 1440 -v -m -M 75fEhQlc9h4 # will download 1080p mp4 avc
# yt -ka 215 ESxIaJWUtAs 75fEhQlc9h4 # two audio files simultaneously at 215kbit/s + original audio files
yt "$@"