QU-16 Editor?

[daubi]

attached some files with extra bytes after the CRC. I guess this happens when you overwrite a sceen. Had to rename it to txt as the forum software does not like .DAT

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[daubi]

@Rayn meanwhile I’m back with the idea of CRC.
The tricky part is: how do they calculate it?
I have constructed 2 scenes with the same settings, same Name, but different scene numbers , ending up in different .DAT file names. starting with A1 00 FE 06 and the other A1 00 FE 07. They end up with the same CRC. So I guess the first 4 bytes are not within the CRC calculation.
Might be the same for the A5 makers, as there a easily to check, whether they are correct or not.

And for the math: changing scene name from Scene 1 to Scene 2, changes 2 bits, ending up in different CRC. 11 4C 68 A7 and EA B8 BE 74

By the way tricky part was to put all faders to max low, as there could be some “noise” in the position data otherwise.

Next task will be to make a CRC tool.

[Ryan]

@daubi I’d need to check the specific way they combine the current crc with the next byte (starting a few bytes after the file start, up until 4 bytes before the file end), but it is roughly the equivalent of crc = lut[byte^(crc&0xFF)] because of their implementation flaw. There might’ve also been a shift in the value used as an index to the lut.

[daubi]

@Rayn I missed your reply.
what makes me wonder: the CRC is 4 bytes long. your propose is byte oriented. And if they use lut (look up table) how to find that one?

I made some test with a python script
https://github.com/antonmeyer/AH_DAT_Files/blob/master/tools/calcCRC.py

no success so far.
to be fair, I even have no glue how the binascii.crc32 really works.

[Ryan]

@daubi It isn’t a proper CRC, since the CRC calculated in previous steps isn’t mixed with the CRC for the new byte — the CRC at each step is taken from the lut (256 entries) based on the value looked up for the previous byte (with an xor thrown in for the new byte).

[daubi]

but how you can find the values in the lut? and how to get a 4 byte “CRC” from a byte function?
and which range in the file is included in this calculation?

[garyh]

Couldn’t an offline editor basically be something similar to the QU-Pad app that just stores all the settings to a file as midi commands, then when connected to the board, you just dump the file to the board? The board doesn’t care how the commands are received, whether live from an app or sequentially from a file.

[daubi]

that could be an option, but
you loose a portion of the haptic of the user interface.
I could accept it, if this software would run on a small
computer and you can transfer the scene setup via an extra
robust button (bluetooth, WLAN)

[Ryan]

Couldn’t an offline editor basically be something similar to the QU-Pad app that just stores all the settings to a file as midi commands, then when connected to the board, you just dump the file to the board? The board doesn’t care how the commands are received, whether live from an app or sequentially from a file.

There are limitations to what settings can be changed with midi. The Qu-Pad app uses a custom protocol to transfer settings/control the mixer.

[garyh]

I thought qu-pad uses midi over ip. Even with limitations, couldn’t you use it to create different mixes when you don’t have access to the board and then during the gig, dump the settings between songs, bands, etc?

The Android app Mix Station is pretty complete. Make something similar that can save all its settings then can dump the settings to the board.

What would really be great is if you could play qu recorded multitracks through the app while you’re creating presets so you could get approximate levels.

[Anonymous]

You’ll never get multitracks over wifi. But the QuPad protocol could be used to dump complete state to the mixer…

Would be a really nice option to have…

[grantr22]

[garyh]

Since you would be using the app offline, the multitrack files would be stored locally on your device and playing while setting up the presets. No WiFi involved until you go online.

[Anonymous]

Yeah, but the iPad would then have to emulate all the processing power of the Qu?

[Ryan]

The hard part might be getting the multitrack recording to the device — iOS users would need camera connection kit (I don’t know anyone who owns this…) and there might be adapter hoops Android users must hop through in order to connect the USB drive with the recordings on it to their device, if the tablets even support external USB devices.

For a desktop editor, that would be much easier.

Just playing back the audio files without effects/processing at relative volume levels would probably be manageable, if you want accurate EQ, gating, and so on… things become more difficult (to implement) and increase processing power required.

[Author]

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