Capture

Capturing TotalMix FX traffic

This proceduce requires a Linux system with a UDC, such as Raspberry Pi 4, 5, or Zero, as well as normal host USB ports.

Run the following to create a MIDI gadget that mirrors a UCX II.

UDC=fe980000.usb                          # raspberry pi 4 udc (see /sys/class/udc)

modprobe usb_f_midi                       # load midi gadget
cd /sys/kernel/config/usb_gadget
mkdir g1                                  # create gadget
cd g1

mkdir strings/0x409 functions/midi.usb0   # instantiate english strings and midi function

# UCX II
echo 0x2a39 > idVendor
echo 0x3fd9 > idProduct
echo 'Fireface UCX II (XXXXXXXX)' > strings/0x409/product
echo 2 > functions/midi.usb0/in_ports     # 2 input ports
echo 2 > functions/midi.usb0/out_ports    # 2 output ports

# UFX II
#echo 0x2a39 > idVendor
#echo 0x3fd1 > idProduct
#echo 'Fireface UFX II (23932050)' > strings/0x409/product
#echo 3 > functions/midi.usb0/in_ports     # 3 input ports
#echo 3 > functions/midi.usb0/out_ports    # 3 output ports

# 802
#echo 0x0424 > idVendor
#echo 0x3fdd > idProduct
#echo 'Fireface 802 (XXXXXXXX)' > strings/0x409/product
#echo 2 > functions/midi.usb0/in_ports     # 2 input ports
#echo 2 > functions/midi.usb0/out_ports    # 2 output ports

mkdir configs/c.1                         # add config
ln -s functions/midi.usb0 configs/c.1/    # attach midi function to config

echo "$UDC" > UDC                         # bind gadget to udc

The MIDI ports for this gadget will appear as f_midi:0 and f_midi:1. MIDI messages from TotalMix FX come through f_midi:1. You can dump them with aseqdump -p f_midi:1.

Determine the client and port for your real device by finding it in the output of aconnect -l. Again, we are interested in port 1. On my system, it appeared as 32:1. You can dump the traffic from the device with aseqdump -p 32:1.

To connect the USB gadget with the real device, create connections between these two ports (one in each direction):

aconnect f_midi:1 32:1
aconnect 32:1 f_midi:1

To remove the gadget, you can run the following:

echo '' > UDC                             # unbind from udc
rm configs/c.1/midi.usb0                  # detach midi function from config
rmdir strings/0x409 configs/c.1 functions/midi.usb0 # remove strings, config, and midi function
cd ..
rmdir g1                                  # remove gadget