[AudioI] Elk Audio OS

Mon Apr 5 06:43:58 UTC 2021

I’ve been able to run the stereo injector with 32 samples buffer on Raspbian with the RT patched kernel, with JACK. Albeit with quite some overhead, just piping input to output took ~20% CPU (one core) on a RPi3B+. This I think is where Elk OS excels.

From: People <people-bounces at lists.audioinjector.net> On Behalf Of Matt via People
Sent: Monday, 5 April 2021 02:19
To: Christopher D'Costa <dcostac86 at gmail.com>
Cc: people at lists.audioinjector.net
Subject: Re: [AudioI] Elk Audio OS

I'm interested to know how close a regular linux OS distro, such as buildroot or Raspbian can get to Elk's 1ms latency ? For the apps you want to run, if their scheduling priorities are set to a maximum, how close do you think it can get ?

Here is an example in code of what I mean by scheduling priority change : https://github.com/flatmax/gtkiostream/blob/master/include/ALSA/ALSA.H#L58<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fflatmax%2Fgtkiostream%2Fblob%2Fmaster%2Finclude%2FALSA%2FALSA.H%23L58&data=04%7C01%7Crobert.bielik%40dirac.com%7C64abaf8488d94396684408d8f7c874bd%7C266f25c575d44d978f448d816a1f6a35%7C1%7C0%7C637531787621844553%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=KgjRKEphMiHA6qfbiSe2ZwV7Ry%2BthYg5A2HQ%2BNq%2BvII%3D&reserved=0>

Matt
On 5/4/21 10:15 am, Christopher D'Costa wrote:
Dang indeed. Was hoping for an Aussie bit of kit that I could try with Elk given how long it takes for anything to ship.

Cheers Matt! Thanks for looking into this.

On Mon, 5 Apr 2021, 7:53 am Matt, <matt at audioinjector.net<mailto:matt at audioinjector.net>> wrote:

Ouch ! Elk OS is all custom register writing !

Check here for example :

https://github.com/elk-audio/rpi-rtdm-audio-driver/blob/master/pcm5122-elk.c#L58-L70<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Felk-audio%2Frpi-rtdm-audio-driver%2Fblob%2Fmaster%2Fpcm5122-elk.c%23L58-L70&data=04%7C01%7Crobert.bielik%40dirac.com%7C64abaf8488d94396684408d8f7c874bd%7C266f25c575d44d978f448d816a1f6a35%7C1%7C0%7C637531787621844553%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=YCt9pH%2BYGn2S9p%2BKdvJgBPM7SNPTmlPxRzOuzp%2FiLOg%3D&reserved=0>

This will have to be a community support thing.

Matt
On 5/4/21 9:25 am, Christopher D'Costa wrote:
This looks like the most detail I can find. The guys at Elk say it's possible, as long as the audio driver exists.

https://github.com/elk-audio/rpi-rtdm-audio-driver<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Felk-audio%2Frpi-rtdm-audio-driver&data=04%7C01%7Crobert.bielik%40dirac.com%7C64abaf8488d94396684408d8f7c874bd%7C266f25c575d44d978f448d816a1f6a35%7C1%7C0%7C637531787621854546%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ezO7DWVBhcJgfHTP3zhg2zqfoXrAkqy6hFbGC8i9oEw%3D&reserved=0>

https://source.denx.de/Xenomai/xenomai<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsource.denx.de%2FXenomai%2Fxenomai&data=04%7C01%7Crobert.bielik%40dirac.com%7C64abaf8488d94396684408d8f7c874bd%7C266f25c575d44d978f448d816a1f6a35%7C1%7C0%7C637531787621864543%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Gkc6gX6CklVOuJu2jpqhCPoa6aFdNkzBji%2BTRQVgv9M%3D&reserved=0>

The OS itself being for musicians seems better suited to the Audio Injector stuff than it is to the HiFiBerry.

On Mon, 5 Apr 2021, 5:55 am Matt, <matt at audioinjector.net<mailto:matt at audioinjector.net>> wrote:

Any information anywhere on the Elk Audio OS - what hardware, kernel, etc etc ?
On 4/4/21 11:36 am, Christopher D'Costa via People wrote:
It's the same ADC and DAC chip as the HiFiBerry from what I can tell. So should be pretty straight forward right?

They use different audio codecs. It will take some work.

On Sun, 4 Apr 2021, 8:06 am Randy Reichenbach, <randaji at gmail.com<mailto:randaji at gmail.com>> wrote:
I'm sure hoping that someone responds with a "yes", but I have a feeling it's currently, "not yet".

Here's a thread from a little over a year ago:
https://forum.elk.audio/t/is-the-elk-pi-hat-essential-for-running-the-elk-audio-os/128/4<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fforum.elk.audio%2Ft%2Fis-the-elk-pi-hat-essential-for-running-the-elk-audio-os%2F128%2F4&data=04%7C01%7Crobert.bielik%40dirac.com%7C64abaf8488d94396684408d8f7c874bd%7C266f25c575d44d978f448d816a1f6a35%7C1%7C0%7C637531787621864543%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=wysKbNMlpkhYXRZQ32Rnfs5jzHeuExIg76bA9geI5eo%3D&reserved=0>

The existing ALSA based AudioInjector driver won't work with Elk.  Someone would have to explicitly create a real-time audio driver (again I'm hoping, but not finding).

The ray of sunshine might be that ELK did it for HifiBerry:
https://elk.audio/elk-audio-os-%e2%99%a5-hifiberry/<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Felk.audio%2Felk-audio-os-%25E2%2599%25A5-hifiberry%2F&data=04%7C01%7Crobert.bielik%40dirac.com%7C64abaf8488d94396684408d8f7c874bd%7C266f25c575d44d978f448d816a1f6a35%7C1%7C0%7C637531787621874538%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=9V8l5OAamVcppCaf9FJmplj8o%2FQRaN3PxTYIcXc2B14%3D&reserved=0>

AudioInjector could probably help their sales if they created an ELK driver for us.  Hint, hint.

On Sat, Apr 3, 2021 at 3:10 PM Christopher D'Costa via People <people at lists.audioinjector.net<mailto:people at lists.audioinjector.net>> wrote:
Hey Michael,

Do you know if Elk Audio OS will be compatible with any of your ADC ADC products?

Cheers,
Chris

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