Hi-md Full Functionality

[b_k_d]

------------------------------

The State of the Hi-MD Hack

------------------------------

The following is a wildly apocryphal, and highly speculative attempt at unifying the

information available on the state of hacking the current line if Hi-MD player/recorders

to function as nature intended.

Feel free to make suggestions and/or corrections if you dare.

---------------

The Elephant

---------------

The makers of these devices have seen fit to force their owners to make all music PC to Device transfers

through what they occasionally refer to as a 'magic gate'. The idea is that you own the device, you may even

own the media, but we will not trust you with the bits. And every transfer of 'sound' bits from the device

to another device shall be mediated by a piece of software which imposes some arbitrary set of restrictions

on what can, and when it can be transferred and in which direction. This is akin to GM installing a Chocolate

Chip cookie monitor in every vehicle, to prohibit the rampant spread of interstate cookie piracy and distribution.

There are numerous undeniably legal uses that would benefit from getting around this scheme, and many other

most-probably legal uses that would benefit as well.

Specifics:

1. We can only transfer files recorded via MIC or LINE-IN from MD to PC.

2. We can only transfer said file 1 time from MD to PC.

3. Optically recorded files are not transferable from MD to PC.

4. SoundStage is the the only way to access the music portion of the MD data.

5. Mac folks have no hope (that said Virtual PC should work).

--------------

What we know

--------------

1. Light-side vs Dark-Side [ -samplehunter ]

- When mounted as a USB drive, the HI-MD device shows a directory of files of the form

-HI-MD.IND

+HMDHIFI

|

|- 00010012.HMA

|- ATDATA04.HMA

|- MCLIST03.HMA

|- MCLIST04.HMA

|- TEXT_G01.HMA

+- TRKIDX04.HMA

This is the 'light-side' data, that is data we can touch and see.

It is presumed (not proven just yet) that there is a portion of the disc that the player reads and writes to

and is not exposed via usb - This is aptly called the 'Dark-Side'.

Why do we care:

1. Research that points to this dark-side data being used as a part of the encryption of the data

2. A bit for bit copy of a MD would be nice for backup purposes.

Examples: Folks have attempted to copy light-side data from one disk to another, or even old light-side data

on top of new light side data. It works functionally, but the player will not play the data.

--------------------

Technical Hurdles:

--------------------

1. Getting to the data - the meta-data (or most of it) is available through the HMDHIFI directory structure

the question is how can we that into a list of music files?

2. Using the data - the data stored on the disk is encrypted and/or obfuscated - such that once we access the

music files how will we get them in a form we can play or edit on the pc?

3. Modifying/Adding music data - the 'encryption'/verification scheme seems to depend on more data than the

FAT data visible via a usb connection

-------------------

Breakthroughs !

-------------------

** Reading Tracknames

- There are 2 programs that can extract track names an put them in human readable form

1. himd-idx - (alexoft)

2. himdlister - (marcnet)

The both work by analyzing the file: TRKIDXNN.HMA and pulling the track names from it

** Reading Data

1. himd_xtract - (fishstyc) - will extract OMG files from a mounted Hi-MD player.

2. himd_renderer - (marknet) - will convert an OMG file to .wav, .mp3, or .ogg

Hi-md renderer uses the SoundStage libraries to convert the files.

Sony has also released a OMG to wav converter.

-----------------

Ultimate Goals

-----------------

1. Tops in the unfeasible, but most helpful - would be to find a way to modify the device to record the OMG,

PCM files in the clear FAT part of the disk, and to play OMG, PCM or MP3 files placed on the light-side

of the disk.

2. Secondary but much more feasible would be to have an installable filesystem driver, that would mount the

Hi-MD files as the device sees them, allowing drag-and-drop to and from the disk.

examples:

gmailfs : http://richard.jones.name/google-hacks/gma...filesystem.html

gmail drive shell exension: http://www.viksoe.dk/code/gmail.htm

Both cases extend google mail's storage system to make it appear as a regular

drive to the client system (os-x does this with ftp, and .mac also)

FUSE - seems a likely candidate for doing the same with the data exposed

via usb connection on a Hi-MD device.

-----------------

Misc.

-----------------

Where's the work being done: Some amazing folks at the forums.minidisc.org

Who wrote this: Some software geek who just got a Hi-MD recorder and suddenly has a

an unusually keen interest in the details of Hi-MD.

Edited May 16, 2005 by b_k_d

[toxigenicpoem]

Interesting, so when can we expect to see some functioning work on software being made in this direction?

[poorlyconditioned]

So, where is this program "himd_xtract"? I looked on this board and couldn't find it.

Is it able to transfer OMA files from the Minidisc to the computer *without* sonicstage?

If so, that would mean we could transfer *saftely*, without risk of losing our files.

Thanks,

Richard

[bug80]

Good work. I think this should be in "Technical Topics", by the way.

It would be really interesting to see if we can touch the "Dark side" in one way or another (nice name for this area by the way ). It seems that this is the part of Hi-MD that differs the most from the Sony HDD players, where the database with file information is accessible in conventional ways.

If I ever buy a 2nd gen Hi-MD unit (likely for the moment, only the possibility that the hardware MP3 decoder is screwed may change my mind), I will start playing with the file system immediately (it's in my nature, can't help it).

[JFK]

Infact there is another reference to himd_xtract on the board, see here.

And you will be able to donwload it here, with reference to this post for its usage.

Edited May 16, 2005 by Ishiyoshi