Re: [fluid-dev] FluidSynth on embedded platforms, zero boot time?

[Geoff Plitt]

Thanks! Yes I'm getting great results with RPi Zero, using an I2S DAC. I will look into FreeRTOS, ChibiOS, eCos.

On Mon, Dec 31, 2018 at 5:50 AM Carlo Bramini <address@hidden> wrote:

Hello!
yes, I succeded to run FluidSynth on an embedded platform.
I have built a digital piano and I used FluidSynth as a rendering engine.

First of all, I would like to suggest you to read this message:

http://lists.nongnu.org/archive/html/fluid-dev/2018-11/msg00022.html

with some results from my experiments.

I suggest you to abandon the idea to use things like Arduino and similar, they are simply not powerful enough. Technically, something like the Raspberry Pi, even the Zero version, and other single board computers are the best and the cheapest solution for running FluidSynth.
But as you already noticed, their boot time is very slow, if compared to an usual microcontroller which is up and running in few milliseconds. I know that there are some ports of RTOS for the Raspberry Pi, like FreeRTOS, ChibiOS and eCos, but I never tried them.

It depends on what you want to do: in my project, I did a small board with a PIC18F25K50 for scanning the keyboard matrix of the piano and provides an USB port and the legacy MIDI-IN/MIDI-OUT. Then, I could connect to the USB port with several hosts like a PC or a phone.
I also tried to do some all-in-one solutions, with an embedded ARM Cortex M3 or a PDA, but I was not able to get decent results, as you could read in the report that I linked in this email.

So, if the all-in-one is what you want, my suggestion is to try again with a single board computer (Raspberry Pi is good, but you must also remember to add an I2S DAC because PWM audio is bad and slow) and try one of the RTOS solutions currently available. Porting is not difficult, I did some of them (Windows, DJGPP and others) without much problems. However, if you have some doubts, just ask.

Sincerely.


> Il 30 dicembre 2018 alle 20.55 Geoff Plitt <address@hidden> ha scritto:
>
> I'm working on a musical instrument that uses FluidSynth for playing SoundFonts, works great. But I'm using Raspberry Pi (Raspbian) and there's a 30-60 second boot time, so I'm looking at other platforms with sub-5-second boot time. I'm really looking to replicate the experience of hardware synths, where you turn it on and it's ready to make sounds in a few seconds at most.
>
> Has anyone had success building/running FluidSynth on an embedded platform with minimal OS, like Arduino, Teensy, Adafruit Feather, etc? Let's say the system has an SD card and DAC/amp to output audio to little speakers, but not a full POSIX environment.
>
> I found  https://github.com/divideconcept/FluidLite but it doesn't include audio output and doesn't look maintained.
>
> My other approach might be to strip out unnecessary parts of Raspbian to get a fast boot time, but the documentation I've found still indicates it's hard to get under 10 seconds.
>
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