youtube_chapter.sh

#!/bin/sh
set -x

#Download media + metadata
youtube-dl --write-info-json -x --audio-format mp3 -o "tmp_out.%(ext)s" $1

# Maybe a way to get the file name from previous function
INFO="tmp_out.info.json"
AUDIO="tmp_out.mp3"
echo :: $INFO $AUDIO ::
# Fetch the title
TITLE=$(cat "$INFO" | jq -r .title | sed -e 's/[^A-Za-z0-9._-]/_/g' )
                                                #  ^--- Remove all weird character as we want to use it as filename
# We will put all chapter into a directory
mkdir "$TITLE"

# Chapterization
cat "$INFO" |\
jq -r '.chapters[] | .start_time,.end_time-.start_time,.title ' |\
sed -e 's/[^A-Za-z0-9._-]/_/g' |\
xargs -n3 -t -d'\n' sh -c "ffmpeg -y -ss \$0 -i \"$AUDIO\" -to \$1 -codec:a copy  -f mp3  \"$TITLE/\$2.mp3\""

#Remove tmp file
rm tmp_out*

Hello @totetmatt ,
I want to use your script to download audio from a youtube video and splitting with the chapters set on the video.
But, there is an error with xargs on macOS Big Sur :

./youtube_chapter.sh https://www.youtube.com/watch\?v\=IF_0W1cYPYo
+ youtube-dl --write-info-json -x --audio-format mp3 --audio-quality 0 -o 'tmp_out.%(ext)s' 'https://www.youtube.com/watch?v=IF_0W1cYPYo'
[youtube] IF_0W1cYPYo: Downloading webpage
[info] Writing video description metadata as JSON to: tmp_out.info.json
[download] Destination: tmp_out.webm
[download] 100% of 66.84MiB in 00:02
[ffmpeg] Destination: tmp_out.mp3
Deleting original file tmp_out.webm (pass -k to keep)
+ INFO=tmp_out.info.json
+ AUDIO=tmp_out.mp3
+ echo :: tmp_out.info.json tmp_out.mp3 ::
:: tmp_out.info.json tmp_out.mp3 ::
++ cat tmp_out.info.json
++ jq -r .title
++ sed -e 's/[^A-Za-z0-9._-]/_/g'
+ TITLE=Dune_-_Spice_Opera
+ mkdir Dune_-_Spice_Opera
mkdir: Dune_-_Spice_Opera: File exists
+ cat tmp_out.info.json
+ sed -e 's/[^A-Za-z0-9._-]/_/g'
+ jq -r '.chapters[] | .start_time,.end_time-.start_time,.title '
+ xargs -n3 -t '-d\n' sh -c 'ffmpeg -y -ss $0 -i "tmp_out.mp3" -to $1 -codec:a copy  -f mp3  "Dune_-_Spice_Opera/$2.mp3"'
xargs: illegal option -- d
usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]
             [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]
             [-s size] [utility [argument ...]]
+ rm tmp_out.info.json tmp_out.mp3

Is there a workaround to use it on macOS ?

Thanks.

Thank you for this script @totetmatt!

@MilesTEG1, on macOS, you can get GNU xargs by installing:

brew install findutils

Then in the script, use gxargs instead of xargs.
It should work.