Hi,
Today I released hinawa-rs[1], Rust bindings to libhinawa v2.0[2].
Aug 2018 I sent a message[3] about new releases of libhinawa/hinawa-utils. In the releases, I used Python 3 to write tools for audio and music units on IEEE 1394 bus, supported by ALSA firewire stack. The attempt is successful to make my understandings further about vendor-dependent protocols.
Earlier the message, Nov 2016 I had a presentation about ALSA device control service in user space[4]. The idea requires server program to perform some tasks below in user space:
* register control element set into ALSA control core for existent card instance * dispatch control event from ALSA control applications * communicate with device to operate its functions such as volume control * dispatch any event from the device.
The registered control element set can be handled transparently by ALSA control applications such as amixer. When the application operates the added control element, events are delivered to the server program. Then the server program communicates with the device for the operation.
Now instead of Python 3, I select Rust language to write the server programs for audio and music units on IEEE 1394 bus. The hinawa-rs helps the third and fourth of the above tasks.
For the first and second task, I wrote some libraries in alsa-gobject project[5]. The demonstration by Python 3 is public[6]. I already write alsa-gobject-rs which includes Rust bindings for the libraries. It's not public yet since I make no official releases of alsa-gobject itself.
At the same time, I already write the prototype of server programs itself and it works well in my local. The code base already reaches 28,000 lines even if it supports the limited number of devices. I realized again that it was a better decision not to implement them in kernel land.
As IEEE 1394 bus becomes legacy, the audio and music units is outdated. One of my motivation to continue the development is the idea of control service in use space itself since the idea is also available for USB Audio as well.
When developers work for devices with vendor-dependent protocol, the idea helps the developer because user space applications can communicate with the device via USB character device. For example, I recently saw an attempt by Guy Sherman for US-4x4 Utils[7]. As a quick glance to his repository[8], vendor-dependent command is used to operate the device. For this kind of work, the idea is available as well to produce transparent control element set.
Anyway I'm going to make official release of alsa-gobject as a next step toward the idea.
[1] https://github.com/takaswie/hinawa-rs [2] https://github.com/takaswie/libhinawa [3] https://www.alsa-project.org/pipermail/alsa-devel/2018-August/139448.html [4] https://github.com/takaswie/presentations/blob/master/20161101/content.md [5] https://github.com/alsa-project/alsa-gobject [6] 'self.open(card_id)' should be 'self.open(card_id, 0)' now https://mailman.alsa-project.org/pipermail/alsa-devel/2019-December/159339.h... [7] https://lists.linuxaudio.org/archives/linux-audio-dev/2020-May/037774.html [8] https://github.com/guysherman/tascam-util
Regards
Takashi Sakamoto