OpenMG file formats part 2

NOTE*2
54-57 4 bytes
	seems to be the track file size but is often
        wrong (apparently) when compared to the figure
        given in the database, and (my poor 
        calculations) of the data transfered over 
        the usb
	
	for example
	a track of silence (1 second)
	database says 		16,896
	omg file says		16,896	(0x00004200)
	actual omg file size	17,517
	total usb transfer size	16,944 (including 16
          byte header)

	audio track
	database says 		4,885,863
	omg file says		4,880,256   (0x004a7780)
	actual omg file size	3,961,025
	total usb transfer size	approx 4,883,432  
		(including 16 byte header)
	
	could perhaps be number of samples

total header = 98 bytes

Audio
	Audio data actually starts in the omg file at 
	offset 0x5a the four bytes preceeding this are
	the number of bytes in the audio block.
	
	while the audio block starts at offset 0x5a 
	the values up to offset 0x62 seem constant. 
	It appears that this range corresponds to the 
	header for the encrypted audio (the audio data 
	seems to be an independent file included as an entry
	in the .omg file)
	

At the end of the audio a new array is opened that
contains
	23 byte tag OMG:FRINGE:USR:user.xml
	arbitrary length tag contining XML description of 
	the track


---------------------------------
USB LP2 Transfer to net MD device

The data bulk transfered via usb to the NetMD device 
consists of :

0-15 	16 bytes

	** for LP2 encoding
		the first 8 bytes seem always to be
		00 00 00 00 00 00 3f 00
	

		the second 8 bytes vary from track to 
                track but are the same for multiple 
                downloads of the same track. A hash or
                key of some kind perchance?

	** for Stereo encoding

		thefirst 8 bytes appear related to size
                of track the second 8 bytes are always
                 00 unlike for LP2 tracks
	some examples of the first 8 bytes for Stereo 
        transfer
	silence
		00 00 00 00 00 02 c0 00  1 second

	A	
		00 00 00 00 03 0e e0 00  4:50	sec = 290

	bach
		00 00 00 00 03 a3 b0 00  5:46 sec = 346 secs

	vivaldi	
		00 00 00 00 01 54 80 00  2:06 sec = 126 secs

16-end
	the contents of the usb appear identical to the 
	contents of the OMG (LP2) file described above 
	with the first 98 bytes removed. It appears that 
	jukebox reencodes Stereo files on the fly from 
	the LP2 OMG file stored on the hardisk


	All bytes right up to the end of the omg audio 
	data block (to the new array declaration (30 80) 
	starting the omg trailer)are included in the 
	transfer
	Also removed should be the trailing stuff

	including the 
		29 byte tail 
		2  byte xml size
		xml size bytes
		4  byte file end marker 
	


Other files that can be examined 

	Program Files\Common Files\Sony Shared\OpenMG
	\EMDKEY\???\cert.dat
	These files appear to be certificates for a 
	variety of software that uses the OpenMG libs

	on my system these are
	???==001  is OpenMG Jukebox
	???==002  is Windows Media Player
	???==003  is IBM EMMS Player
	???==004  is Liquid Audio Player

	these files all start with
	30 80 30 80  (nested array definition so 
			software works)

	the priv.dat files are very similar

duftam

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