BASH script to conform MP3 artwork to make the Kenwood Excelon series head units happy

kenwood.sh

#!/bin/bash

# This script will iterate through a folder and conform the artwork for any MP3s to a standard that is pleasing 
# to the Kenwood Excelon series of car audio head units. It assumes all files in the folder are from the same album.
# (Note that this has been tested on a Kenwood Excelon DMX809S, but I assume this will work for all Excelon products.)
#
# This script will look for cover art contained in the folder first. If none is found, it will attempt to extract embedded
# artwork from the alphabetically first MP3.
#
# As far as I can tell, these are the criteria for the Kenwood Excelon to display album artwork:
#   1. Must be embedded in the MP3 -- images in folders are not read.
#   2. Must be perfectly square.
#   3. Must be less than 500KB. (This is the ONLY criterion mentioned in the manual, btw.)
#   4. I don't know what the upper size limit is, but 500x500px seems to be safe.
#   5. Color space must be sRGB.
#
# Note that there are additional criteria, but the above are the criteria that relate to the actual image. Additional criteria
# (and more BASH scripts) are outlined here:
# https://jmatthewturner.wordpress.com/2025/05/29/usb-mp3-functionality-on-kenwood-excelon-head-units/
#
# This was written by Claude.ai, with prompts from jmatthewturner. I have refined it a bit, but it's 95% AI generated. 
#
# https://gist.github.com/jmatthewturner/41c210d3ec3dedd70e4cc8efa00e95e7

#############
# VARIABLES #
#############
first_mp3=0 #   the first mp3 encountered by the for loop
cover_img=0 #   the cover art, if available

#################
# MAIN FUNCTION #
#################

echo "Starting Kenwood.sh..."

# Look for cover art already saved in the folder under common file names
if [ -f "Cover.jpg" ]; then
    echo "Found Cover.jpg."
    cover_img="Cover.jpg"
elif [ -f "Cover.png" ]; then
    echo "Found Cover.png."
    cover_img="Cover.png"
elif [ -f "cover.jpg" ]; then
    echo "Found cover.jpg."
    cover_img="cover.jpg"
elif [ -f "cover.png" ]; then
    echo "Found cover.png."
    cover_img="cover.png"
elif [ -f "folder.jpg" ]; then
    echo "Found folder.jpg."
    cover_img="folder.jpg"
elif [ -f "folder.png" ]; then
    echo "Found folder.png."
    cover_img="folder.png"
elif [ -f "cover.webp" ]; then
    echo "Found cover.webp."
    cover_img="cover.webp"
else    
    # If no artwork is found in the folder, attempt to extract artwork embedded with the tag "FRONT_COVER Image"
    # from the first MP3 file. If the cover art is embedded, this will create FRONT_COVER.jpg/png.

    first_mp3=$(ls *.mp3 | head -n 1)
    echo "No artwork found in folder. Attempting to extract from $first_mp3..."
    echo
    eyeD3 --write-images=. "$first_mp3"

    # Check to see if cover art was extracted. If so, set cover_img to the extracted artwork.
    if [ -f "FRONT_COVER.jpg" ]; then
        echo "FRONT_COVER.jpg successfully extracted from $first_mp3."
        cover_img="FRONT_COVER.jpg"
    elif [ -f "FRONT_COVER.png" ]; then
        echo "FRONT_COVER.png successfully extracted from $first_mp3."
        cover_img="FRONT_COVER.png"
            else 
                # At this point, all attempts to locate artwork have failed.
                echo "No cover image found!"
                exit 1
    fi
fi

# Conform the image with ImageMagick
convert "$cover_img" -strip -resize 500x500\! -colorspace sRGB cover_conformed.jpg
echo "Conformed $cover_img to cover_conformed.jpg."

# Embed the conformed image into all MP3s in the folder
echo "Embedding cover_conformed.jpg into all MP3s..."
echo
for f in *.mp3; do
    eyeD3 -Q --remove-all-images "$f"
    eyeD3 -Q --add-image "cover_conformed.jpg:FRONT_COVER" "$f"
done

# Clean up temporary images
#rm "$cover_img" cover_conformed.jpg
echo
echo "Skipping temp file removal."

# Report success
echo "Done processing album art for all MP3s in this folder."
if [ "$first_mp3" == "0" ]; then
    echo "Found $cover_img in folder, successfully conformed to cover_conformed.jpg and embedded in all files."
else echo "Successfully extracted artwork from $first_mp3, conformed to cover_conformed and embedded in all files."
fi

echo

# Exit successfully
exit 0