Saturday, 25 August 2012

W*H*O*O H*O*O !!!!!!!

Time to fess up. It was all me. Stupid, stupid me. Classic, removed 2 lines of code whose function I didn't understand as they sort of seemed to not do much. Idiot.

Anyway, now I've slapped myself about the head with a large plank, let me point out that the latency problem has now gone. Absolutely, utterly, totally gone. There is to a first approximation NO LATENCY*. None. You can throw fingers all over the keyboard and sounds just come out. At the same time as you press the key. Wicked. Crisp and immediate and fantastic.

This thing is a beast. Video to follow, but most likely not til Tuesday folks, I think I need to take the Bank Holiday weekend off.

*Yes, proper signal processing folks and physicists can shoot me for that, but you all know what I mean.


  1. You tease...

    Are you planning on releasing this? Commercial or FOSS?

    Also, this seems like a (relatively) cheap way to output from something other than your TV:

  2. Absolutely not FOSS, it will become at least one iOS app and it will form the underpinnings of commercial releases on non-Raspberry Pi hardware. The biggest block to getting it into other peoples hands right now is that it needs a custom MIDI interface of which only 3 exist (of which 2 are known to work), all in my house and all hand-lashed and hacky. It's pretty trivial, it's just a PIC taking in 31250 over the optocoupled interface and spitting out 38400 at 3v3 RS232 into the Pi, but it's not something you can go out and buy today.

    So if my USB MIDI problems shake out maybe it will make sense as a software-only thing for the Pi. But it won't be free, I need to eat.

    Thanks for the link to that breakout box by the way, that could come in useful.

  3. I'm using a normal USB-Class compliant MIDI setup with my Raspberry Pi, no custom hardware required .. USB-MIDI just plain works, anyway.

    1. Wish I could say the same - I'm still flummoxed by USB audio. I have a piece of code that works fine on a Linux desktop machine, works fine on two different Tegra-based platforms (TrimSlice and Toradex Colibri), but whenever I try it on the Pi my playback sample rate drops from 44k to about 3k samples/sec. Need to dig in further, but very frustrated by this.