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A DVD player has the suitable hardware for more use than just DVD's.
Would it be possible to actually code the menu systems in a way to make an operating system?

I guess that depends on what's inside. Most consumer electronics devices contain some kind of CPU / application processor and some piece of software. If that software is stored in a re-writable memory, there is at least a small chance that it can be replaced with custom software. However, it is usually very hard to actually write such software, and even harder to place it on the device. The main problem is that there is only little or no documentation about the hardware internals.

If you are very lucky, someone has already disassembled your DVD player model and figured out which chips are in there, maybe there are even datasheets available for those chips.

Just out of curiosity: Which DVD player model do you have? Have you ever disassembled it and figured out what's inside?

VCR os.. Storing homework on a VHS tape

I was more thinking along the lines of how the menus on DVD's work. You could set it up to use the up/down/left/right arrows to move a cursor instead of selecting menu items. If you wrote it into the DVD disc then it could run on any DVD player.

Maybe this could help you:

http://dvdauthor.sourceforge.net/doc/r1741.html

The syntax for the menu and title selection is indeed a very simple "programming language", so at least you can create some rather arbitrary (although still very limited) menu structure. But I wouldn't call at an OS.

Most DVD players have a SoC that can handle the DVD menu instruction bytecode, a general purpose core that runs the firmware with the GUI and handles user input.. audio/video decoding probably takes place on a hardware accelerator.

Some players do support firmware updates.. so assuming you can figure out the firmware update format and the GP core architecture, then sure, maybe.

You'll need to reverse engineer just about everything, no documentation is likely to exist.

GhostXoPCorp wrote:VCR os.. Storing homework on a VHS tape

That's actually somewhat practicle Of course, assuming that they're not entirely hardware controlled... Be cool to turn one into a terminal and save data to tape though...

You could rewire the RCA in/out ports on the VCR to a serial or parallel cable and then use it to read/write raw data to VCR tapes.

I don't know about DVD players but in setup top boxes and satellite tuners, for paid TV for example MIPS processors have been often chosen. They are often programmed in some high level language like Java and sometimes it is very noticeable as some of the products have very sluggish menus. However, Java done right with the correct CPU is usually fine.

On the OS side some Java OSes have been used, and I'm sure Linux is used as well. I think there is a large variety of OSes running on DVD players so I think it can be difficult to know them all. Does anybody have a real world example?

Blu-ray disks can have Java programs with quite a lot more capability than DVD menus. Blu-ray players are probably also thus more susceptible to firmware update hacking. Both of those might be interesting.

OSwhatever wrote:I don't know about DVD players but in setup top boxes and satellite tuners, for paid TV for example MIPS processors have been often chosen. They are often programmed in some high level language like Java and sometimes it is very noticeable as some of the products have very sluggish menus. However, Java done right with the correct CPU is usually fine.

I have a satellite receiver with a BCM7405 MIPS CPU running Linux. On top of that there is a software named Enigma2 which is written mostly in Python with a bit C++ and which generates most of the menus. One can easily add plugins written in Python and there are lots of them on the web. It's really fun to play with this box

Does anyone know what language DVD menus are written in? My guess is XML or the like.

Found it!
IS VM DVD command set.
Learning....