Audio to MIDI convertion

strato0100 · October 10, 2021, 2:36am

Hello, I’m new in Pisound world, I found it an amazing thing.

I’m using MODEP with my guitar and I was wondering if is there a way to convert the audio signal to MIDI so it can be used to sinth another instrument like a violin or a saxophone, etc…

Does anybody knows something about it! I’ll appreciate any direction.

datashaman · October 11, 2021, 3:07am

Hi,

Disclaimer: I have not used these products. These two seem to be market leaders:

https://migic.com/
https://www.jamorigin.com/

I can’t find any open source projects worth mentioning on github. There are traces of attempts to do it, but no one appears to have got live guitar working, and all attempts stopped years ago.

strato0100 · October 11, 2021, 8:02pm

Hi, thank you, those seem to be amazing software but unfortunately doesn’t run on Linux.
In my research I found Rakarrack, and open source software that has a tool to convert audio signal into MIDI signal but it only works for single notes since it uses a monophonic conversor.

Now I’m searching the way to convert audio signal to polyphonic MIDI.

datashaman · October 12, 2021, 5:59am

One of the founders of Migic published this a while back. It supposedly includes a form of the same engine used by Migic. And it runs on RPi.

The only problem is it’s vaporware - there’s nothing that is usable unless you are him. But it could mean that something will be released by Migic themselves at some point. Perhaps a less powerful version of the software that runs their current products.

Giedrius · October 12, 2021, 7:17am

Looks like all the magic is hidden in this call to their proprietary library

github.com

ripxorip/pico_guitar_to_midi/blob/master/src/main.c#L180

    
      
                  {
                      /* Convert the data to Q16 */
                      buffer[i] = ((int32_t)(dma_buffer[i])-(2048-60)) << 5; // 60 for resistor variance..
          
          
#ifndef NDEBUG
                      write_logger[log_index+i] = buffer[i];
          #endif
                  }
          #ifdef NDEBUG
                  /* Call libmigic withe the processing buffer */
                  libmigic_track(buffer, CAPTURE_DEPTH, &midiMsgs[0], midiBufferSize, &numberOfMessages, F16(0.1), F16(0.11), false, false, false);
                  for (size_t i = 0; i < numberOfMessages; i++)
                  {
                      tudi_midi_write24(0, midiMsgs[i].bytes[0], midiMsgs[i].bytes[1], midiMsgs[i].bytes[2]);
                      if (midiMsgs[i].bytes[0] == 0x90)
                      {
                          gpio_put(LED_PIN, 1);
                          gpio_put(BENCHMARK_PIN, 1);
                      }
                      else if (midiMsgs[i].bytes[0] == 0x80)
                      {

strato0100 · October 12, 2021, 8:40pm

Looks like we got stuck again ultil could find a way to convert the audio signal to polyphonic MIDI.

I found this amazing project https://github.com/jaym910/polyphonic_track but it doen’t run on Raspberry since it uses then python library scikit-learn and it seems to use some Intel processor functions.