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#221079 - 22/02/2002 14:29 Active Playlist file hacking..
brturn
new poster

Registered: 08/02/2000
Posts: 16
Loc: Cary, NC
Looking at the most recent version of Emplode, I noticed a feature to 'insert' and 'add to end' of the active playlist.

How do these features work? What is the file on the empeg/central which contains the active playlist? Can I write to this file dynamically, in order to build a playlist on the fly (akin to WinAmp's playlist window)?

Currently I'm trying to find this information for the empeg, but I assume it will be applicable it to the central as soon as it arrives.

Thanks!
--Bryan
[email protected]

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#221080 - 22/02/2002 14:43 Re: Active Playlist file hacking.. [Re: brturn]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
If the Jupiter's anything like the empeg car player in this respect, then the current song running order is stored on a specially-formatted "scratch" partition, separate from the rest of the software. It's not stored in a file.

The layout of this special partition is not completely known. It's proprietary, and the folks hacking on the empeg car player are only just beginning to figure it out.

The reason it was done this way on the car player was disk/shock/powerloss protection. A failure during this write operation to a regular hard disk partition would cause irritating things to happen, like long disk checks. By keeping their own format and keeping the partition separate, they can protect the data using their own more robust techniques.
_________________________
Tony Fabris

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#221081 - 22/02/2002 15:19 Re: Active Playlist file hacking.. [Re: tfabris]
brturn
new poster

Registered: 08/02/2000
Posts: 16
Loc: Cary, NC
Hmm.. that doesn't sound like an easy thing to play with then. Perhaps emulating the interface of Emplode..?

Are there any hacker docs on the scratch partition, or on the emplode protocol (other than the JEmplode source)? I did some protocol sniffs of the append command, it seems fairly straight forward, but there are a few loose ends (like why it sends 0x00 - 0xFF in a packet.. WTF is that for?).

It was a quick project idea, but it may be above my threshhold for pain on this project. *sigh*

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#221082 - 22/02/2002 15:22 Re: Active Playlist file hacking.. [Re: tfabris]
brturn
new poster

Registered: 08/02/2000
Posts: 16
Loc: Cary, NC
While we're on the topic...

I'm new to *nix OS's. How can I open 'the scratch partition' to take a look at the data therin? Is it a special parameter/filename for an fopen() call, or is there another API?

Does the scratch partition have a filesystem, or is it handled by the app?

Thanks!
--Bryan
[email protected]

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#221083 - 22/02/2002 16:07 Re: Active Playlist file hacking.. [Re: brturn]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Perhaps emulating the interface of Emplode..?

Yes, source code for this is available. The original source code is Emptool over on the empeg web site. Don't remember if Emptool/Jemplode has Play and Insert code yet, though. Guys?
_________________________
Tony Fabris

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