Maschinist

Here I am attempting to build a system to automatically tag loops and one-shot .wav samples for use in Maschine.

Spelunking

Hex Fiend (or any other good hex editor/viewer) is a great tool for starting to dig into this.

Clue #1: Importing a sample that was pretagged.

I imported a sample that was from Loopmasters and was surprised to see that it came with tags. Also there was a Maschine error message that noted some values were invalid and needed to be converted.

Opening that sample in our fiendly hex editor revealed the following data embedded in the sample.

ID3 ì   ID3     	bGEOB   X     com.native-instruments.soundinfo <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<soundinfo version="400">

  <properties>
	<name>TE_Cymbal_1</name>
  </properties>

  <banks>
	<bank>Loopmasters</bank>
  </banks>

  <attributes>
	<attribute>
	  <value>Percussion</value>
	  <user-set>GB.Type</user-set>
	</attribute>
	<attribute>
	  <value>Pop LM</value>
	  <user-set>GB.Type</user-set>
	</attribute>
  </attributes>

</soundinfo>

After a bit of digging through the ID3 standards it looks like Maschine uses Generic Embedded Objects from the ID3v2 media tagging standard.

Trying to reverse the process

I imported a junk sample into my Maschine library and added the following metadata. Here is the GEOB portion of ID3v2 extracted from a sample that was tagged with test data to try to work out the underlying encoding:

• Content Type: Loop
• Types: Drums, Texture
• Character: Special FX, Stabs & Hits, Surround, Synth, Tambourine, Tempo-synced
• Properties:
  • Vendor: Awesome Vendor
  • Author: Special Author
  • Comment: So many comments... so much to say.. I mean... you gotta go out there and give 110%.... every time.

While I could see the data in the hex editor I wanted to access it programmatically. I tried a few libraries and I can't recall which, but I know that mutagen was the only one that did what I needed:

Python 3.9.9 | packaged by conda-forge | (main, Dec 20 2021, 02:41:06) 
[Clang 11.1.0 ] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import mutagen
>>> mutagen.File("metadata.wav")
{'GEOB:com.native-instruments.nks.soundinfo': GEOB(encoding=<Encoding.LATIN1: 0>, mime='', filename='', desc='com.native-instruments.nks.soundinfo', data=b'\x88\xad__ni_internal\x81\xa6source\xa5other\xa6author\xaaTestAuthor\xa7comment\xabTestComment\xa5modes\x94\xa8Acoustic\xa8Additive\xa4Airy\xa6Analog\xa4name\xa8metadata\xa5tempo\xcb\x00\x00\x00\x00\x00\x00\x00\x00\xa5types\x93\x91\xa8Ambience\x91\xa4Bass\x91\xa5Drums\xa6vendor\xaaTestVendor'), 'GEOB:com.native-instruments.nisound.soundinfo': GEOB(encoding=<Encoding.LATIN1: 0>, mime='', filename='', desc='com.native-instruments.nisound.soundinfo', data=b'\x02\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00m\x00e\x00t\x00a\x00d\x00a\x00t\x00a\x00\n\x00\x00\x00T\x00e\x00s\x00t\x00A\x00u\x00t\x00h\x00o\x00r\x00\n\x00\x00\x00T\x00e\x00s\x00t\x00V\x00e\x00n\x00d\x00o\x00r\x00\x0b\x00\x00\x00T\x00e\x00s\x00t\x00C\x00o\x00m\x00m\x00e\x00n\x00t\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x07\x00\x00\x00\n\x00\x00\x00\\\x00.\x00A\x00c\x00o\x00u\x00s\x00t\x00i\x00c\x00\n\x00\x00\x00\\\x00.\x00A\x00d\x00d\x00i\x00t\x00i\x00v\x00e\x00\x06\x00\x00\x00\\\x00.\x00A\x00i\x00r\x00y\x00\x08\x00\x00\x00\\\x00.\x00A\x00n\x00a\x00l\x00o\x00g\x00\n\x00\x00\x00\\\x00:\x00A\x00m\x00b\x00i\x00e\x00n\x00c\x00e\x00\x06\x00\x00\x00\\\x00:\x00B\x00a\x00s\x00s\x00\x07\x00\x00\x00\\\x00:\x00D\x00r\x00u\x00m\x00s\x00\x00\x00\x00\x00\x07\x00\x00\x00\x07\x00\x00\x00\\\x00@\x00c\x00o\x00l\x00o\x00r\x00\x01\x00\x00\x000\x00\x11\x00\x00\x00\\\x00@\x00d\x00e\x00v\x00i\x00c\x00e\x00t\x00y\x00p\x00e\x00f\x00l\x00a\x00g\x00s\x00\x01\x00\x00\x000\x00\x0b\x00\x00\x00\\\x00@\x00s\x00o\x00u\x00n\x00d\x00t\x00y\x00p\x00e\x00\x01\x00\x00\x000\x00\x07\x00\x00\x00\\\x00@\x00t\x00e\x00m\x00p\x00o\x00\x01\x00\x00\x000\x00\x06\x00\x00\x00\\\x00@\x00v\x00e\x00r\x00l\x00\x06\x00\x00\x001\x00.\x007\x00.\x001\x004\x00\x06\x00\x00\x00\\\x00@\x00v\x00e\x00r\x00m\x00\x06\x00\x00\x001\x00.\x007\x00.\x001\x004\x00\x07\x00\x00\x00\\\x00@\x00v\x00i\x00s\x00i\x00b\x00\x01\x00\x00\x000\x00')}
>>> 

And the objects formatted:

{
	'GEOB:com.native-instruments.nks.soundinfo': 
		GEOB( encoding=<Encoding.LATIN1: 0>, 
			  mime='', 
			  filename='', 
			  desc='com.native-instruments.nks.soundinfo', 
			  data=b'\x89\xad__ni_internal\x81\xa6source\xa5other\xa6author\xaeSpecial Author\xa7comment\xd9dSo many comments... so much to say.. I mean... you gotta go out there and give 110%....  every time.\xaadeviceType\xa4LOOP\xa5modes\x96\xaaSpecial FX\xacStabs & Hits\xa8Surround\xa5Synth\xaaTambourine\xacTempo-synced\xa4name\xa8metadata\xa5tempo\xcb\x00\x00\x00\x00\x00\x00\x00\x00\xa5types\x92\x91\xa5Drums\x91\xa7Texture\xa6vendor\xaeAwesome Vendor'
		), 
	'GEOB:com.native-instruments.nisound.soundinfo': 
		GEOB(encoding=<Encoding.LATIN1: 0>, 
			 mime='', 
			 filename='', 
			 desc='com.native-instruments.nisound.soundinfo', 
			 data=b'\x02\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00m\x00e\x00t\x00a\x00d\x00a\x00t\x00a\x00\x0e\x00\x00\x00S\x00p\x00e\x00c\x00i\x00a\x00l\x00 \x00A\x00u\x00t\x00h\x00o\x00r\x00\x0e\x00\x00\x00A\x00w\x00e\x00s\x00o\x00m\x00e\x00 \x00V\x00e\x00n\x00d\x00o\x00r\x00d\x00\x00\x00S\x00o\x00 \x00m\x00a\x00n\x00y\x00 \x00c\x00o\x00m\x00m\x00e\x00n\x00t\x00s\x00.\x00.\x00.\x00 \x00s\x00o\x00 \x00m\x00u\x00c\x00h\x00 \x00t\x00o\x00 \x00s\x00a\x00y\x00.\x00.\x00 \x00I\x00 \x00m\x00e\x00a\x00n\x00.\x00.\x00.\x00 \x00y\x00o\x00u\x00 \x00g\x00o\x00t\x00t\x00a\x00 \x00g\x00o\x00 \x00o\x00u\x00t\x00 \x00t\x00h\x00e\x00r\x00e\x00 \x00a\x00n\x00d\x00 \x00g\x00i\x00v\x00e\x00 \x001\x001\x000\x00%\x00.\x00.\x00.\x00.\x00 \x00 \x00e\x00v\x00e\x00r\x00y\x00 \x00t\x00i\x00m\x00e\x00.\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x0c\x00\x00\x00\\\x00.\x00S\x00p\x00e\x00c\x00i\x00a\x00l\x00 \x00F\x00X\x00\x0e\x00\x00\x00\\\x00.\x00S\x00t\x00a\x00b\x00s\x00 \x00&\x00 \x00H\x00i\x00t\x00s\x00\n\x00\x00\x00\\\x00.\x00S\x00u\x00r\x00r\x00o\x00u\x00n\x00d\x00\x07\x00\x00\x00\\\x00.\x00S\x00y\x00n\x00t\x00h\x00\x0c\x00\x00\x00\\\x00.\x00T\x00a\x00m\x00b\x00o\x00u\x00r\x00i\x00n\x00e\x00\x0e\x00\x00\x00\\\x00.\x00T\x00e\x00m\x00p\x00o\x00-\x00s\x00y\x00n\x00c\x00e\x00d\x00\x07\x00\x00\x00\\\x00:\x00D\x00r\x00u\x00m\x00s\x00\t\x00\x00\x00\\\x00:\x00T\x00e\x00x\x00t\x00u\x00r\x00e\x00\x00\x00\x00\x00\x07\x00\x00\x00\x07\x00\x00\x00\\\x00@\x00c\x00o\x00l\x00o\x00r\x00\x01\x00\x00\x000\x00\x11\x00\x00\x00\\\x00@\x00d\x00e\x00v\x00i\x00c\x00e\x00t\x00y\x00p\x00e\x00f\x00l\x00a\x00g\x00s\x00\x01\x00\x00\x008\x00\x0b\x00\x00\x00\\\x00@\x00s\x00o\x00u\x00n\x00d\x00t\x00y\x00p\x00e\x00\x01\x00\x00\x000\x00\x07\x00\x00\x00\\\x00@\x00t\x00e\x00m\x00p\x00o\x00\x01\x00\x00\x000\x00\x06\x00\x00\x00\\\x00@\x00v\x00e\x00r\x00l\x00\x06\x00\x00\x001\x00.\x007\x00.\x001\x004\x00\x06\x00\x00\x00\\\x00@\x00v\x00e\x00r\x00m\x00\x06\x00\x00\x001\x00.\x007\x00.\x001\x004\x00\x07\x00\x00\x00\\\x00@\x00v\x00i\x00s\x00i\x00b\x00\x01\x00\x00\x000\x00'
		)
}

Sadly no easily readable XML, but a somewhat decipherable binary encoding. Perhaps the XML was an older standard used by Native Instruments?

Breaking Down the first GEOB

\x89\xad__ni_internal\x81\xa6source\xa5other\xa6author\xaeSpecial Author\xa7comment\xd9dSo many comments... so much to say.. I mean... you gotta go out there and give 110%....  every time.\xaadeviceType\xa4LOOP\xa5modes\x96\xaaSpecial FX\xacStabs & Hits\xa8Surround\xa5Synth\xaaTambourine\xacTempo-synced\xa4name\xa8metadata\xa5tempo\xcb\x00\x00\x00\x00\x00\x00\x00\x00\xa5types\x92\x91\xa5Drums\x91\xa7Texture\xa6vendor\xaeAwesome Vendor

One common pattern seems to be that textual sections are preceded by a single byte where the first four bits are constant 0x1010 (10) and the next four bits represent the length of the value.

For example:

\xad__ni_internal

0xAD = 0b10101101 which yields 0b1010 and 0b1101 (10 and 13). 10 appears to be a constant of some sort and 13 is the length of __ni_internal

We see this many times in this sample:

• \xa6source 0xA6 -> 0b1010 and 0b0110 (10 and 6)
• \xa5other 0xA5 -> 0b1010 and 0b0101 (10 and 5)
• \xa6author 0xA6 -> 0b1010 and 0b0110 (10 and 6)
• \xaeSpecial Author 0xAE -> 0b1010 and 0b1110 (10 and 14)
• \xa7comment 0xA7 -> 0b1010 and 0b0111 (10 and 7)

One interesting this is the actual comment which is much longer than the 16 characters that can be accounted for in 4 bits. The comment is preceded by two bytes:

\xd9dSo many comments... so much to say.. I mean... you gotta go out there and give 110%.... every time.

• 0xD9 -> 0b11011001
• d or 0x64 -> 0b01100100 or 100, which is the length of the comment text.

For contrast in a previous test I used 'TestComment' as the comment text and the tag included:

\xabTestComment

0xAB -> 0b1010 and 0b1011 (10 and 11)

So it seems like there is some special case where strings longer than 16 characters have an additional marker.

Possible off the shelf/default encoders?

At this point I have a partial understanding of the encoding, so let's see if we can find a serialization scheme that fits.

• Binn: format kinda fits, but some parts just don't seem to work and I couldn't decode the binary data with a Binn deserializer... so likely nope.
• BSON: This one's easy... the document size prefix is missing.. Nope.
• Smile The magic byte sequence for Smile isn't present here... Nope.
• MessagePack Very promising, looks like a good match.

Let's try to work with it:

>>> import msgpack
>>> packed = b'\x89\xad__ni_internal\x81\xa6source\xa5other\xa6author\xaeSpecial Author\xa7comment\xd9dSo many comments... so much to say.. I mean... you gotta go out there and give 110%....  every time.\xaadeviceType\xa4LOOP\xa5modes\x96\xaaSpecial FX\xacStabs & Hits\xa8Surround\xa5Synth\xaaTambourine\xacTempo-synced\xa4name\xa8metadata\xa5tempo\xcb\x00\x00\x00\x00\x00\x00\x00\x00\xa5types\x92\x91\xa5Drums\x91\xa7Texture\xa6vendor\xaeAwesome Vendor'
>>> unpacked = msgpack.unpackb(packed)
>>> unpacked
{b'__ni_internal': {b'source': b'other'}, b'author': b'Special Author', b'comment': b'So many comments... so much to say.. I mean... you gotta go out there and give 110%....  every time.', b'deviceType': b'LOOP', b'modes': [b'Special FX', b'Stabs & Hits', b'Surround', b'Synth', b'Tambourine', b'Tempo-synced'], b'name': b'metadata', b'tempo': 0.0, b'types': [[b'Drums'], [b'Texture']], b'vendor': b'Awesome Vendor'}
>>> packed2 = msgpack.packb(unpacked)
>>> packed == packed2
False
>>> packed
b'\x89\xad__ni_internal\x81\xa6source\xa5other\xa6author\xaeSpecial Author\xa7comment\xd9dSo many comments... so much to say.. I mean... you gotta go out there and give 110%....  every time.\xaadeviceType\xa4LOOP\xa5modes\x96\xaaSpecial FX\xacStabs & Hits\xa8Surround\xa5Synth\xaaTambourine\xacTempo-synced\xa4name\xa8metadata\xa5tempo\xcb\x00\x00\x00\x00\x00\x00\x00\x00\xa5types\x92\x91\xa5Drums\x91\xa7Texture\xa6vendor\xaeAwesome Vendor'
>>> packed2
b'\x89\xad__ni_internal\x81\xa6source\xa5other\xa6author\xaeSpecial Author\xa7comment\xda\x00dSo many comments... so much to say.. I mean... you gotta go out there and give 110%....  every time.\xaadeviceType\xa4LOOP\xa5modes\x96\xaaSpecial FX\xacStabs & Hits\xa8Surround\xa5Synth\xaaTambourine\xacTempo-synced\xa4name\xa8metadata\xa5tempo\xcb\x00\x00\x00\x00\x00\x00\x00\x00\xa5types\x92\x91\xa5Drums\x91\xa7Texture\xa6vendor\xaeAwesome Vendor'

Not perfect... but very close.

The only difference is The encoding of the comment. The original was \xd9dSo many comments... and the reencoded version is \xda\x00dSo many comments... . Looking at the msgpack spec the only difference is that the re-encoded version used two bytes to represent the string length instead of one.

As per the msgpack spec on strings:

str 8 stores a byte array whose length is upto (2^8)-1 bytes:
+--------+--------+========+
|  0xd9  |YYYYYYYY|  data  |
+--------+--------+========+

str 16 stores a byte array whose length is upto (2^16)-1 bytes:
+--------+--------+--------+========+
|  0xda  |ZZZZZZZZ|ZZZZZZZZ|  data  |
+--------+--------+--------+========+

I think we have a winner.

{
	b'__ni_internal': {
			b'source': b'other'
	}, 
	b'author': b'Special Author', 
	b'comment': b'So many comments... so much to say.. I mean... you gotta go out there and give 110%....  every time.', 
	b'deviceType': b'LOOP', 
	b'modes': [b'Special FX', b'Stabs & Hits', b'Surround', b'Synth', b'Tambourine', b'Tempo-synced'], 
	b'name': b'metadata', 
	b'tempo': 0.0, 
	b'types': [
		[b'Drums'], [b'Texture']
	], 
	b'vendor': b'Awesome Vendor'
}