converts currently playing audio track + picture from clipboard to webm video

musicwebm.zsh

#!/usr/bin/env zsh
# exit on errors
set -e
tempdir="/tmp"

if [[ -n $1 ]]
then
    audio_file=$1
    track_length="$(ffprobe $1 2>&1|sed -n 's/.*Duration: \([^,]\+\),.*/\1/p')"
elif pgrep mocp > /dev/null
then
    audio_file="$(mocp -i | sed -n 's/^File: //p')"
    output_name="$(mocp -i | sed -n 's/^Title: //p')"
    track_length="$(mocp -i | sed -n 's/^TotalTime: //p')"
elif pgrep deadbeef > /dev/null
then
    audio_file="$(deadbeef --nowplaying %F)"
    output_name="$(deadbeef --nowplaying %t)"
    track_length="$(deadbeef --nowplaying %l)"
else
    echo "nothing to do"
    exit 1
fi
if [[ -n $2 ]]; then
    # picture got as second argument
    picture_file=$2
elif [[ "$(xclip -t TARGETS -o)" =~ image ]]; then
    # clipboard has a picture!
    xclip -t image/png -o $tempdir/p.png
    picture_file=$tempdir/p.png
else
    # get picture path from clipboard
    picture_file="$(xclip -o)"
    # workaround for geeqie (it copies file path with single quotes)
    [[ picture_file =~ ^'.+'$ ]] && picture_file="$(echo $picture_file | sed "s/^'//; s/'$//; s/'\\\\'//;")"
fi
[[ -z $output_name ]] && output_name=${audio_file:t:r}
# replace slashes with backslashes
[[ $output_name =~ '/' ]] && output_name=${output_name:gs/\//\\}
aopts=(-q:a 5)
#aopts=(-c:a libopus -application audio -vbr on -b:a 95k -strict -2)
aopts=(-c:a copy)

[[ -f $output_name.webm ]] && echo "$f exists" && false
ffmpeg -hide_banner -i $audio_file -vn -sn $aoptsi -map_metadata 0 -y $tempdir/a.webm
for pass in 1 2
    ffmpeg -hide_banner -loop 1 -r 1 -i $picture_file \
        -t $track_length -pass $pass  -auto-alt-ref 1 -lag-in-frames 16 -y $tempdir/v.webm
        #-vf 'setpts=10*PTS' \
mkvmerge /tmp/v.webm /tmp/a.webm -o $output_name.webm