See Folders? My Car player does.
It's how I got it to play albums in chronological order rather than alphabetical order, you number the albums (actually you number
& name the folders) then it will play the folders in numerical order
after playing all the tracks in each folder in numerical order.
It is why I developed my music library organization system
So for example an individual track on my HDD becomes
Music\mp3(320k)\Rush\14 Hold Your Fire\002 Time Stand Still.mp3
In practice on a CD-R it gets abbreviated to:
Rush\14 Hold Your Fire\002 Time Stand Still.mp3
Most car players will choke if the first file they encounter
(in the first folder) is anything other than an "acceptable" AUDIO file type, so if you want to "hide" other data on the disc you must put those files in a directory/folder that comes AFTER the audio files alphanumerically.
My car player will play whatever type of audio file (WAV or MP3 only)
it encounters first and IGNORE all other file types, including other audio files, so I cannot "mix" wav and mp3 on a single disc.
Yes, it will play CD-R's loaded with WAV data files IOW a
non-finalized, non-compliant disc.
Many units however are not so tolerant.
If you want to "hide" .pdf .jpg or gif files on a disc put them in a folder named
"ZZ" these will generally get written to the disc LAST
and thus the player (if a "tolerant one" will either ignore them or never see them.
As the saying goes "Your Mileage May Vary".
You will need to expirement do so with RW discs
If your player will play them, it'll save you from opening
a coaster factory.