General information on how DVD players and their firmware (or software)

[Samazama]

I just flashed my LG stand-alone regular-old-DVD-player, and it made me curious. The first thing I noticed was that the files I used on the CD I burned were "recycled" from another brand/model of player. Also, rather than being a series of commands put through the remote, I had to use a disc. Do all DVD players essentially use the same code? So, where would I find more information on what makes a DVD player tick inside? The files on the CD were not text-based, so I couldn't look at them. Can I access the code on the DVD player somehow?

Thank you

[KCinLA]

This DVD FAQ has been extremely useful for me, http://dvddemystified.com/dvdfaq.html

[tomlee59]

There are relatively few OEM drives, which are then packaged up and rebranded by many others. "Under the hood" (or bonnet) of many different brands will live a common mechanism.

Of course you shouldn't expect a human-readable file on a firmware disc, as it contains binary code written for the drive's microcontroller, not you. One who is schooled in the art of programming embedded processors could, in principle, understand the code (once the family of microntrollers has been identified). But without documentation, you aren't going to get far. So if you had dreams of hacking on your own, understand that this is a nontrivial task.

[Samazama]

How would you copy, de-compile and edit the code? What language is it in? Are any of the values stored in text? Are most of these hack discs based on a technician's disc?

Thank you,
Sama

[tomlee59]

I'm sorry to say, but the fact that you are asking these questions strongly suggests that you aren't going to get too far. Since you didn't quite understand what I've already written, here is more detail on what you would have to do:

1) Find out, for your particular model, what family of controller core is being used. This is not generally advertised -- you will have to do your own sleuthing to find out. Open up your player, look at the chips. Correlate the markings with manufacturers. Do research to find out what family of microcontroller is typically favored by that manufacturer. Hope that it's one of the common ones (e.g., ARM, Renesas, Freescale, etc.)

2) Learn how to program those microcontrollers.

3) Reverse-engineer the meaning of key variables (whatever variables you want to change).

4) The disc is unlikely to contain much in the way of human-readable strings. As I've already said, firmware is for computers, not humans. You are looking at object code, not source code. It's already been compiled for that microcontroller.

5) Give up this fantasy. It's beyond you (no insult intended, it's just a fact).