(See part 1.)

As long as .pla file is binary, we will view it in hex. Here's a hex dump of a playlist containing first three tracks of Led Zeppelin IV:

$ hd lz4.pla
00000000  00 03 00 01 00 00 00 00  01 40 00 04 00 00 3d 60  |.........@....=`|
00000010  01 40 00 0e 00 00 3d 60  01 40 00 02 00 00 3d 5f  |.@....=`.@....=_|
00000020

This playlist is named `lz4.pla'. We will refer to it below.

Header

I've created several playlists "manually" and noticed that the second byte is always equal to the number of tracks in playlist (`03' in lz4.pla). Bytes with offsets 0 and 2–7 are the same for all playlists I've seen. Thus we can guess the format of .pla file header:

00 <nn> 00 01 00 00 00 00,

where <nn> is number of tracks in playlist.

Entry

Playlist header is followed by entries — 8-byte-long track specifications. There are as many entries as there are tracks in a playlist (lz4.pla file has three: address ranges 0x8–0xf, 0x10–0x17, and 0x18–0x1f).

When we open playlist in Motorola, we see the names of tracks included. But there is no chance for 8 bytes of .pla entry to contain the name of track: the third track is displayed as `03 - The Battle of Evermore' making a string of 27 characters.

Thus, we can assume that .pla entry encodes position of .mp3 file within the underlying filesystem.

Continued...