Want to Build an audio playback OS from scratch. Need guidance.

[manueljenkin]

Hi Everyone, hope you're doing good.

 

I wish to build an audio playback OS from scratch either in Linux or in BSD. I would want to do it as an exercise to get to know the deeper implementations.

 

I would like to build something similar to Wtfplay. Most services except usb, hard drive support and usb dac support, and a very basic I/o (yet to decide the mode) to be not included, so as to keep the OS minimal. The hardware support shall also be specific to the image.

 

I would like to know where I can find the ALSA code which specifically implements USB audio class 2 (Asynchronous) protocol. Can anyone guide me on that? I did see a basic alsa playback code - https://gist.github.com/ghedo/963382/815c98d1ba0eda1b486eb9d80d9a91a81d995283 , but I wish to see what is inside the ALSA code. I wish to build an entire audio kernel/mixer from the ground up, albeit a simple one without many features, but supporting usb audio class 2 Asynchronous mode.

 

I would also love guidance for building linux from scratch to support just raspberry Pi 3.

 

Thanks and Regards,
Manuel Jenkin.
 

[Miska]

IIRC, wtfplay uses normal Linux.

 

But why would you want to do audio kernel / mixer at all in first place?

 

If you want to take a look at good one on top of ALSA, take a look at JACK. I worked on Jack1 long time ago.

 

[Miska]

17 hours ago, manueljenkin said:

I would like to know where I can find the ALSA code which specifically implements USB audio class 2 (Asynchronous) protocol. Can anyone guide me on that?

 

In Linux kernel sources, under sound/usb directory.

 

[manueljenkin]

Thank you @Miska .I'm working on something a little different and I need a fair amount of control over the entire code sequence. I am only using alsa as a reference.

[Richard Dale]

22 hours ago, manueljenkin said:

Hi Everyone, hope you're doing good.

 

I wish to build an audio playback OS from scratch either in Linux or in BSD. I would want to do it as an exercise to get to know the deeper implementations.

 

I would like to build something similar to Wtfplay. Most services except usb, hard drive support and usb dac support, and a very basic I/o (yet to decide the mode) to be not included, so as to keep the OS minimal. The hardware support shall also be specific to the image.

 

I would like to know where I can find the ALSA code which specifically implements USB audio class 2 (Asynchronous) protocol. Can anyone guide me on that? I did see a basic alsa playback code - https://gist.github.com/ghedo/963382/815c98d1ba0eda1b486eb9d80d9a91a81d995283 , but I wish to see what is inside the ALSA code. I wish to build an entire audio kernel/mixer from the ground up, albeit a simple one without many features, but supporting usb audio class 2 Asynchronous mode.

 

I would also love guidance for building linux from scratch to support just raspberry Pi 3.

 

Thanks and Regards,
Manuel Jenkin.
 

If you want to build Linux from scratch, there is a project to document how to do that:

 

http://www.linuxfromscratch.org/

 

 

[seeteeyou]

22 hours ago, manueljenkin said:

I would like to build something similar to Wtfplay.

 

https://www.nexthardware.com/forum/pc-top-software/88276-wtfplay-misurazioni-e-confronti-con-players-14.html#post960061

Quote

Please find below the list of package that have been used to build the distribution and and the corresponding licences.

 

All packages listed below have been build via portage (https://wiki.gentoo.org/wiki/Portage). The source code is in official Gentoo repositories.

 

[manueljenkin]

Thank you @seeteeyou and @Richard Dale . I'm looking into those resources.