[Connected Car] donaldta:
I installed strace to get a handle on how it works. After a bit of testing, it appears that your first hunch was correct. The ck5050 process seems to be loading the mp3's in to the Parrot module. Below, I start tracing the process as I fast forwarded through the different songs.

# [COLOR="RoyalBlue"][B]ps ck5050[/B][/COLOR]
USER PID PPID VSIZE RSS WCHAN PC NAME
parrot [COLOR="Red"]1291[/COLOR] 1 76752 16848 ffffffff afd0c5cc S /system/xbin/ck5050
# [COLOR="RoyalBlue"][B]strace -fp [COLOR="Red"]1291[/COLOR] -o /mnt/sdcard/strace-ck5050.txt[/B][/COLOR]
# [B][COLOR="RoyalBlue"]awk '/mp3/&&/open/ {print $2}' /mnt/sdcard/strace-ck5050.txt | sort | uniq[/COLOR][/B]
open("/mnt/sdcard/amazonmp3/Harry_Connick,_Jr_/Blue_Light_Red_Light/B00136JU4M_(disc_0)_07_-_If_I_Could_Give_You_More.mp3",
open("/mnt/sdcard/amazonmp3/Harry_Connick,_Jr_/Blue_Light_Red_Light/B00136JU7E_(disc_0)_05_-_He_Is,_They_Are.mp3",
open("/mnt/sdcard/amazonmp3/Harry_Connick,_Jr_/Blue_Light_Red_Light/B00136LZ36_(disc_0)_04_-_Jill.mp3",
open("/mnt/sdcard/amazonmp3/Harry_Connick,_Jr_/Blue_Light_Red_Light/B00136LZ90_(disc_0)_08_-_The_Last_Payday.mp3",
open("/mnt/sdcard/amazonmp3/Harry_Connick,_Jr_/Blue_Light_Red_Light/B00136Q752_(disc_0)_10_-_She_Belongs_To_Me.mp3",
open("/mnt/sdcard/amazonmp3/Harry_Connick,_Jr_/Blue_Light_Red_Light/B00136S0KC_(disc_0)_06_-_With_Imagination_(I'll_Get_There).mp3",
open("/mnt/sdcard/amazonmp3/Harry_Connick,_Jr_/Blue_Light_Red_Light/B00136S0KM_(disc_0)_02_-_A_Blessing_And_A_Curse.mp3",
open("/mnt/sdcard/amazonmp3/Harry_Connick,_Jr_/Blue_Light_Red_Light/B00136S0LQ_(disc_0)_12_-_Just_Kiss_Me.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B000UBDLGO_(disc_0)_10_-_My_Funny_Valentine.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B000W0F6GG_(disc_0)_08_-_Sent_for_You_Yesterday_and_Here_You.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B000W0TGN0_(disc_0)_12_-_Moanin'.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B000XA203W_(disc_0)_14_-_Mary_Don't_You_Weep.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B0011Z325S_(disc_0)_15_-_Respect.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B001386MAA_(disc_0)_05_-_How_High_the_Moon_(Live).mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B0013AMS3S_(disc_0)_02_-_Solitude.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B0013ATIGS_(disc_0)_01_-_Boo_Woo.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B001CQMDIS_(disc_0)_16_-_Always_on_My_Mind.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B004M499IY_(disc_0)_06_-_Driftin'_Blues.mp3",
open("/mnt/sdcard/amazonmp3/Various_artists/Ray_Charles_-_Music_that_Matters_to_Him/B00607RLX6_(disc_0)_09_-_We're_All_Together.mp3",
#

I included the output of the file to this post and from it, I learned for the Parrot Media Player that...

The artwork for the current song is written as a JPEG to "/tmp/img/PlayerArtwork" file.

The current song information is written to "/tmp/concertos/Concertos.ini.tmp" in the "0=" line under the [SrcStack] section.

creating a blank file called "/tmp/UniversalLogger" will allow the CK5050 process to log its debugging information into it.

Incidently, PowerAMP and Neutron players do not seem to use the system codecs at all. PowerAmp uses FFMPEG (libffmpeg.so) library which is contained in "/data/data/com.maxmpz.audioplayer/files" directory. Whereas the Neuron player is using both MPG123 (libiauxmpeg.so) and FFMPEG (libiauxcodec.so) in the "/data/data/com.neutroncode.mp/lib" directory. Also, MX Player will use the Texas Instrument MP3 decoder if you enable it to be used as an audio player.