Hacking Mac OSX and HMA files

[funnymachine]

I have just bought an MZ-NH700 having read the marketing and technical specs in the dumb belief that it recorded WAV files to the mini disc and that I would be able to drag drop them into my audio apps.

But I should have known better - after all it's made by Sony!!!

I have tried reverse engineering the HMA files on the disk and they seem to be in some bizarre format, blocks of data in chunks that is neither big endian, little endian, signed or unsigned which is what one would expect from a typical linear PCM file.

Why am I having so much trouble you ask, when there is software available to translate the recording to WAV???

Well the Sony / Mac software won't work with this mini disc - God knows why - well obviously they want people to buy the new model don't they...

So my other solution so far has been to run Sonic Stage 3.2 under Win XP in Virtual PC - which means it takes half a day to transfer anything to the Mac, having to go through the import process under emulation, and a further translation to WAV as for some bizarre reason despite ticking the box, it refuses to do it at the same time.

SOMEBODY HELP!!!

Thanks

T

[Bananatree]

Sadly MD just doesn't work with Mac OSX the way it does in Windows, only the new Mac compatible recorder can upload PCM to a Mac.

[funnymachine]

Sadly MD just doesn't work with Mac OSX the way it does in Windows, only the new Mac compatible recorder can upload PCM to a Mac.

←

Yeh well, thanks for that.. and I got fed up with trying to upload to a Mac so loaded the software onto my girlfriends PC laptop. I can see the minidisc as a drive, but believe it or not I cannot see it at all from within Sonic Stage 3.2

This whole thing sucks...

T

[reefbeef]

even when you click on the transfer menu? Under the pull down, you should see Hi-MD as one of the options. From there you can upload or just hit play and digitally record it with Total Recorder or Audacity (see pinned topics)

[emeb]

I have tried reverse engineering the HMA files on the disk and they seem to be in some bizarre format, blocks of data in chunks that is neither big endian, little endian, signed or unsigned which is what one would expect from a typical linear PCM file.

←

Yeah, a few of us have been hacking on those files too. Here's a link to the info I've compiled so far:

himd_info.tgz

May that will be helpful. Plus, if you find out anything useful, please feed it back to me for inclusion

[marcnet]

Id thought that you might like to add the following information to your info (some of which you already have, but I have repeated to make the rest of this make sense):

First of the initial values/calculations:

Track start pos = [Block List value at offsets 8 & 9] 
Track End pos = [Block List value at offsets 0xa & 0xb] 
End Info value = [Block List value at offsets 0xc & 0xd]
[/code]


NB: Dont multiply the start and end pos values by 0x4000 yet....


Okay, now this part is codec specific. I reference the codecs by the lowest 16 bits (eg: 0x2807 for LPCM). The block waste and factor values are in decimal
[code]
For 0x2030:
   Block Waste = 256
   Factor = 192

For 0x282e:
   Block waste = 216
   Factor = 376

for 0x28b9
    Block waste = 1504
    Factor = 1488

for 0x2822
   Block waste = 144
   Factor = 280

For 0x2026
   BLock waste = 272
   Factor = 304

for 0x2018
   Block waste = 256
   Factor = 192

for 0x2807:
  BLock waste = 64
  Factor = 64

Okay, pick your values from the above and stick them into this. Ive split the calculations up into seperate operations so it looks nicer in your web browser

Length = [Track end pos] - [Track start pos]
Length *= 16384 - [Block waste]
Length += ( 1 + [End info value] ) * [Factor]
[/code]
And thats it. You now have a track length in bytes. At least, I hope you do - this part of my HIMDRenderer program is quite messy and needs tidying up. Ive basically taken my code and (hopefully accuratly) optimized it down to these calculations. 
Oh, and for you non-C programmers:
+=   means take current left hand value and add it to the value at right hand side
*=   means take current left hand value and multiply it to the value at right hand side

[emeb]

Id thought that you might like to add the following information to your info (some of which you already have, but I have repeated to make the rest of this make sense):

<snip>

←

Thanks! I'll update my info.

[funnymachine]

even when you click on the transfer menu?  Under the pull down, you should see Hi-MD as one of the options.  From there you can upload or just hit play and digitally record it with Total Recorder or Audacity (see pinned topics)

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Works on the Mac in Virtual PC - doesn't work on the PC!

Strange

I'll have a look at the format thing later

Thanks

Mark

[darkandspiky]

hi,

can anyone help with this topic:

http://forums.minidisc.org/index.php?showtopic=12333

for example, can you convert the hma files to wavs without the sony software on a mac?

i know they're a pc user, but they could send me the hma files if it's possible to do something with them.

i'm suprised there isn't any unix ports that can deal with these files yet, that i can find anyway.

thanks,

~darkandspiky~

[Breepee2]

i'm suprised there isn't any unix ports that can deal with these files yet, that i can find anyway.

Indeed. DVD, WMAv9, WMAv10, iTunes, iPod, all were hacked within days. Seems MD just isn't interesting enough (or they use an extremely hack-proof encoding system, but I do not think so).

That's why I consider Sony a perfect example of the fact that security through obscurity does work!

[raintheory]

That's why I consider Sony a perfect example of the fact that security through obscurity does work!

[hobgoblin]

That's why I consider Sony a perfect example of the fact that security through obscurity does work!

so, if i want to run a secure webserver it should be some homemade code on top of skyos or something?