Enqueue items (like YouTube playlists) with mpv

mpv-enqueue.sh

#!/usr/bin/env bash
#
#  Enqueue the named file(s) / URL(s) mpv's JSON IPC; starts an instance of mpv
#  if one isn't already found in the process list
#
#  Author:   Kevin Ernst (ernstki -at- mail.uc.edu)
#  Date:     03 July 2019; updated 12 November 2021
#  Source:   https://gist.github.com/ernstki/93bc8653556053e51c41cc1ba0c24255
#
#  Requirements:
#    1. mpv: https://mpv.io/
#       - available in MacPorts on macOS; may need to 'pip install youtube-dl'
#    2. jq: https://stedolan.github.io/jq/
#       - available in most package managers under that name
#    3. 'xclip' (if on Linux)
#    4. 'socat'
#       - also available in MacPorts on macOS
#
(( TRACE )) && set -x
set -u

SOCKET=/tmp/mpvsocket
# wait this long after startup before enqueuing any media
STARTUPDELAY=5
MPVOPTS=(
    # (any options unrecognized by this script are also passed through)
    --geometry='+5%-10%'
    --autofit='25%x25%'
    --idle=once
    --input-ipc-server=$SOCKET 
    # 'pip install yt-dlp' and uncomment this if the video stutters a lot
    --script-opts=ytdl_hook-ytdl_path=yt-dlp
    # ref: https://www.reddit.com/r/mpv/comments/q759xc
    # console output from `mpv` usually has useful information when yt-dlp
    # fails, so don't uncomment unless you're *sure* yt-dlp is working
    #--really-quiet
)

if [[ -t 1 ]]; then
    UL=$(tput sgr 0 1)
    BOLD=$(tput bold)
    RED=$(tput setaf 1)
    RESET=$(tput sgr0)
else
    UL=; BOLD=; RED=; RESET=
fi

ME=$(basename ${BASH_SOURCE[0]})
USAGE="
  $ME - enqueue named file(s) or clipboard contents with mpv

  ${UL}usage$RESET
    $ME [-h|--help] [-s|--show[-playlist|-queue]] [MEDIA [MEDIA...]]
    $ME {-c|--command} JSONIPC

  ${UL}where$RESET
    -h, --help            shows this help
    -s, --show-playlist,  shows the current queue/playlist
        --show-queue
    -p, --pop             pop the last entry off the queue
    -c, --command CMD     send arbitrary JSON IPC command (for testing)            
    MEDIA                 URL or filename(s) to enqueue with mpv
                          (default: read from stdin, then clipboard)

  ${UL}default mpv options$RESET
$(echo ${MPVOPTS[*]} | fold -s -w 78 | sed 's/^/    &/')
    (options unrecognized by this script are also passed through)
"  

if [[ $(uname -s) != Darwin ]]; then
    # requires 'xclip' to be installed
    pbpaste() { xclip -o -sel clipboard; }
fi

_ipc() {
    local output quiet= data= args=()
    while (( $# )); do
        case $1 in
            -q|--quiet)  quiet=1;;
             -d|--data)  data=1;;
                     *)  args+=("\"$1\"");;
        esac
        shift
    done

    # echo "{\"command\": [ $(IFS=,; echo "${args[*]}") ]}"
    output=$(
        socat - $SOCKET <<<"{\"command\": [ $(IFS=,; echo "${args[*]}") ]}"
    )
    (( $? )) &&
        bail "Error sending IPC command '${args[0]}'"

    error=$( jq -r .error <<<"$output" )
    [[ $error == success ]] ||
        bail "Error '$error' sending IPC command '${args[0]}'"

    if (( !quiet )); then
        if (( data )); then
            echo "$output" | jq -r .data
        else
            echo "$output"
        fi
    fi
}

show_playlist() {
    echo
    echo "  Contents of playlist"
    echo "  --------------------"
    _ipc --data get_property playlist | jq -r '"    - " + .[].filename'

    echo
    echo "  Now playing"
    echo "  -----------"
    _ipc --data get_property media-title \
      | fold -s -w 78 \
      | sed 's/^/    &/'
    echo
}

send_command() {
    local pid=$(pgrep mpv)
    _ipc --data "$@" ||
        bail "Error sending IPC command '$*' (mpv pid: $pid)"
}

enqueue_item() {
    local pid=$(pgrep mpv)
    local item=$1
    if _ipc -q loadfile "$item" append-play; then
        echo "Enqueued '$item' (mpv pid: $pid)" >&2
    else
        bail "Error enqueueing '$item' (mpv pid: $pid)"
    fi
}

pop_item() {
    local pid=$(pgrep mpv)
    local count=$(_ipc --data get_property playlist-count) 

    if _ipc --quiet playlist-remove $(( count - 1 )); then
        echo "Popped last entry from playlist (mpv pid: $pid)" >&2
    else
        bail "Error popping from playlist (mpv pid: $pid)"
    fi
}

bail() {
    echo >&2
    echo "  $RED${BOLD}OH NOES!${RESET} $*" >&2
    echo >&2
    exit 1
}

queue=()
mpvopts=("${MPVOPTS[@]}")
output=
pid=
ret=
showplaylist=

# parse input arguments
while (( $# )); do
    case $1 in
        -h|--h*)
            echo "$USAGE"
            exit
            ;;
        -s|--show*)
            show_playlist
            exit
            ;;
        -p|--pop)
            pop_item
            exit
            ;;
        -c|--command)
            shift
            send_command "$@"
            exit
            ;;
        -*)
            mpvopts+=("$1")
            ;;
        *)
            queue+=("$1")
    esac
    shift
done

# if no queue arguments given on command line:
#   - if reading from a pipe/redirection, read that in
#   - else try the clipboard
if [[ ${#queue[@]} -eq 0 ]]; then
    if [[ ! -t 0 ]]; then
        echo "Reading from stdin..." >&2
        readarray -t stdin
        queue+=("${stdin[@]}")
    else
        echo "Checking clipboard..." >&2
        readarray -t clipboard < <(pbpaste)
        queue+=("${clipboard[@]}")
    fi
fi

if [[ ${#queue[@]} -eq 0 ]]; then
    echo >&2
    echo "$USAGE" >&2
    bail "Queue cannot be empty; try passing filenames or URLs"
fi

# start mpv with IPC service enabled, if not running
pid=$(pgrep mpv)
ret=$?

if (( $ret != 0 )); then
    nohup mpv "${mpvopts[@]}" 2>&1 &
    pid=$!
    echo "Started mpv (pid: $pid)" >&2
    sleep $STARTUPDELAY
fi

# spool up the rest by sending messages to the socket
for item in "${queue[@]}"; do
    enqueue_item "$item"
done

Needs to check for presence of socat and bail if it's not found.

FIXME

The script-opts=ytdl_hook-ytdl_path=yt-dlp key isn't supported until v0.33.0 (I think), and Ubuntu 20.04 only has 0.32.0. See this Reddit thread and mpv-player/mpv@93f84b5.

With 0.32.0, you just get the error message

[ytdl_hook] script-opts: unknown key ytdl_path, ignoring

which is silent, and so mpv just quits, no indication of what went wrong in nohup.out, I think because of the --no-terminal option (which I might want to reconsider).

Workaround

pipx install yt-dlp
cd ~/.local/bin
ln -s yt-dlp youtube-dl

And then comment out the line in the script that says

--script-opts=ytdl_hook-ytdl_path=yt-dlp

As a general practice, you're always better off installing yt-dlp with pip or pipx. LTS distros' repositories may include a yt-dlp package, but it's almost guaranteed to be too old to actually work with YouTube. It's a constant arms race.